American Orthopaedic Society for Sports Medicine Annual Meeting 2008 Poster Abstracts Activity Level and Graft Type as Risk Factors for ACL Graft Failure: A Case-Control Study of the MOON Cohort Authors: James R. Borchers MD, Angela Pedroza BS, Christopher C. Kaeding MD (Columbus, OH) Objective: ACL graft failure is a rare event following ACL reconstruction. This study aims to evaluate the risk of graft failure associated with index graft type and subject's activity level at the time of graft failure. Methods: This study is a matched (1:2) case-control design. Cases were identified using the MOON database with indicated ACL graft failure at 2 year follow-up. Cases (N=21) and controls (N=42) were selected from a single surgeon cohort and matched on age and gender. Demographic data was identified from MOON database including time of index surgery, graft type, age and gender. A telephone interview was performed for all subjects. Cases were asked for time of ACL graft failure and Marx activity level for the month prior to graft failure. Controls were asked for Marx activity level at median time of graft failure for cases. Data analysis included summary statistics and logistic regression for evaluation of Marx activity level and graft type as risk factors for graft failure. Results: Median time for graft failure among cases was 11.6 months. Median Marx activity level for cases at time of graft failure was 16 and 12 for controls at median time for graft failure. The odds of graft failure for subjects with Marx activity level > 13 is 4.33 times the odds of graft failure for subjects with Marx activity level < 13 (95% CI 0.89,21.16; p=0.070)controlling for graft type and matched variables. The odds of graft failure in a subject with an allograft is 4.93 times the odds of graft failure for a subject with an autograft (95% CI 1.33,18.19; p=0.017) controlling for activity level and matched variables. Logistic regression failed to identify an interaction between Marx activity level and graft type. Stratum specific odds ratios suggest a relationship between Marx activty level and graft type (Figure 1).
(cont.) Activity Level and Graft Type as Risk Factors for ACL Graft Failure: A Case-Control Study of the MOON Cohort
Figure 1 Stratum Specific Odds Ratios for Marx Activity Level and Graft Type
Conclusions: Subjects with a high activity level in the first year following ACL reconstruction have an increased odds of graft failure compared to subjects with lower activity levels. Subjects with an allograft have an increased odds of graft failure compared to subjects with an autograft in the first year following ACL reconstruction. There appears to be a significant increase in risk for graft failure in subjects with an allograft participating at a high activity level in the first year following ACL reconstruction. Acknowledgements: Multicenter Orthopaedic Outcomes Network (MOON)
The Effect of Tunnel Placement on Bone-Tendon Healing in Anterior Cruciate Ligament Reconstruction in a Goat Model Authors: Max Ekdahl MD, Masahiro Nozaki MD, Andrew Tsai MS, Patrick Smolinski PhD, Freddie H. Fu MD (Pittsburgh, PA) Objective: Tunnel placement is one of the key issues to the success of anterior cruciate ligament (ACL) reconstruction. Some cadaveric studies have shown that different tunnel placements can affect the biomechanical properties of the reconstructed knee.1 Tunnel misplacement has been considered one of the main causes of graft failure after ACL reconstruction. The aim of this study was to evaluate the effect of tunnel placement on bone-tendon healing in ACL reconstruction by analyzing the biomechanical properties and biological healing. Methods: ACL reconstruction was performed on three different groups of goats (one anatomical tunnel placement group and two different non-anatomical tunnel placements groups with 10 goats in each group). In the anatomical tunnel placement group, the ACL reconstruction was performed by placing the graft from the anteromedial bundle (AM) tibial insertion site to the AM bundle femoral insertion site (AM-AM group: Fig 1A). In one of the non-anatomical tunnel placement groups, the graft was placed from the tibial posterolateral bundle (PL) insertion site to the femoral AM insertion site (PL-AM group: Fig 1B). In the second non-anatomical group, the graft was placed from the PL insertion site of the tibia to a high position in the femoral notch (PL-H AM group (H AM = high anteromedial bundle femoral insertion site): Fig 1C). For each group of ten knees, three knees were used for histological evaluation (bone tunnel enlargement, number of osteoclasts at the bone-tendon interface, and revascularization of the graft) and seven knees were used for biomechanical testing (anterior tibial translation and in situ force at three angels of flexion, cross section area, and ultimate failure load). Animals were sacrificed at 12 weeks post surgery. Results: The anatomical tunnel placement group showed less tunnel enlargement on the tibial side (Fig 2A), fewer osteoclasts on both the tibial and femoral sides (Fig 2B), and more vascularity in the femoral side (Fig 2C) when compared with both non-anatomical reconstruction groups. Biomechanically, the anatomical tunnel placement group demonstrated less anterior tibial translation (Fig 3A) and greater in situ force (Fig 3B) than both non-anatomical tunnel placement groups.
(cont.) The Effect of Tunnel Placement on Bone-Tendon Healing in Anterior Cruciate Ligament Reconstruction in a Goat Model
Conclusions: Anatomical tunnel placement leads to superior biological healing and biomechanical properties at 12 weeks after ACL reconstruction in a goat model. References: 1. Musahl V, Plakseychuk A, Fu FH. Varying femoral tunnels between the anatomical footprint and isometric positions. Am J Sports Med. May 2005;33(5):712-718.
Acknowledgements: The authors thank Mario Ferretti, Sheila Ingham, Wei Shen, Mario Ronga, Goro Tajima, Tomoyuki Matsumoto, Kenji Uehara, Takanori Iriuchijima, Andy Holmes, Helga Georgescu, and Gulshan Sharma for their technical assistance. This work was supported by the grants of the Albert B. Ferguson, Jr. MD Orthopaedic Fund of The Pittsburgh Foundation.
The Effect of Relaxin on ACL Integrity Authors: Jason L. Dragoo MD, Kevin Padrez BS, Rosemary Workman BS, Derek Lindsey PhD (Palo Alto, CA) Objective: The hormone relaxin, found in pregnant and non-pregnant females, has been shown to have a collagenolytic effect on ligamentous tissue. Relaxin receptors have recently been identified on human female anterior cruciate ligaments (ACL)1. This study evaluated whether the administration of recombinant relaxin and estrogen or relaxin alone will lead to a significant increase in ACL laxity in the guinea pig model. Methods: Guinea pigs were administered 20 ug/hr of recombinant relaxin ±5 ug/hr of estradiol using separately implanted osmotic pumps. ACL laxity was tested by implanting radio-opaque markers in the femur and tibia of each leg. After applying a standard force (22N) anteriorly translating the tibia, the distance between markers was measured radiographically at day 0 and day 21 compared to controls. The animals were then sacrificed and the ACL’s were analyzed for load-to-failure using a material testing machine. Results: Animals treated with relaxin and estrogen (n=4) showed a significant (p=0.02) increase in ACL laxity under an applied force compared to controls (n=4). Animals only treated with relaxin (n=4) also showed a significant (p=0.04) increase in ACL laxity under an applied force compared to controls (n=4). Load-to-failure testing showed hormone treated ACL’s (Relaxin + Estrogen µ=32.7 N) (Relaxin only µ= 40.4 N) were significantly weaker than controls (µ=64.1 N) (p=0.000).
(cont.) The Effect of Relaxin on ACL Integrity
Figure 1
Load to Failure testing Conclusions: This data suggests that relaxin and estrogen significantly alter the mechanical properties of the ACL in an animal model. The effects of relaxin may contribute to the etiology of female noncontact ACL injuries. References: Dragoo JL, Lee RS, Benhaim P, Finerman GA, Hame SL. “Relaxin receptors in the human female anterior cruciate ligament”. Am J Sports Med, Jul-Aug; 31(4):577-84.
Does ORIF of an OCD Loose Body Lead to Healing and Maintenance of Long Term Knee Function? Authors: Robert A. Magnussen MD, James L. Carey MD, Kurt P. Spindler MD (Nashville, TN) Objective: Osteochondritis dissecans (OCD) can progress to loose body formation resulting in a Grade IV defect. The decision to fix versus excise the loose body is controversial. Published operative fixation outcomes are small case series (10 or fewer patients) with short (less than 5 year) follow-up. We hypothesize that operative fixation (ORIF) of the loose body into the grade IV defect will heal and approximate “normal” knee function at long-term follow-up. Methods: Sixteen patients were identified who underwent ORIF of a knee OCD loose body into the Grade IV osteochondral defects ranging in size from 1.5 to 8.0 cm2 (mean 3.2 cm2). ORIF was performed through a mini-arthrotomy with compression screws and all patients were nonweightbearing for 12 weeks postoperatively. After 12 weeks, arthroscopy was performed for screw removal and the stability of the repaired OCD evaluated by probing. The fifteen patients who were at least 2 years post-surgery were asked if any repeat surgery was performed and to complete the validated Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaire. Results: Second look arthroscopy revealed stable healing by probing in 94% (15/16) of patients. One patient had partial healing of 75% of the defect. After repeat ORIF, the remaining defect was healed 12 weeks later. No patients required subsequent surgery for a loose body. At an average of 8.4 years follow-up (range 3.8-15.8 years) 87% (13/15) completed the KOOS. KOOS subscale scores for pain (mean 88, range 67-100), and function in activities of daily living (mean 92, range 72-100) were not clinically different from published age matched normal patients.(1) However the KOOS subscale for sports and recreation function (mean 71, range 45-100), and knee related quality of life (mean 62, range 31-81) were significantly different {sports and recreation (p < 0.05) and knee related quality of life (p < 0.001)}.(1) Conclusions: Operative fixation of Grade IV OCD loose bodies results in stable fixation. At an average 8 years after surgery, patients did not have symptoms of osteoarthritis pain and had normal function in activities of daily life. However, patients reported significantly lower knee related quality of life and sport and recreation function. Only prospective comparative studies can determine the relative advantages of the available treatment choices for these lesions. References: 1. Paradowski PT, et al. Knee complaints vary...adult population. Population-based ref data for the...KOOS. BMC Musculoskelet Disord. 2006;7(38).
Clinical Outcomes Following the Microfracture Procedure for Chondral Defects of the Knee: A Longitudinal Data Analysis Authors: Bruce S. Miller MD, J. Richard Steadman MD, Karen K. Briggs MPH, MBA, Brian Downie PA (Ann Arbor, Livonia, MI; Vail, CO) Objective: The purpose of this study was to evaluate the outcome of the microfracture procedure in the knee in a large patient sample using a random-effects model for longitudinal data analysis. Methods: 350 patients(avg. age=47.6 year (range, 12 to 76), 65% male;55% female) who underwent the microfracture procedure by a single surgeon for isolated full-thickness chondral defects of the knee were identified for analysis. Data were analyzed with a random-effects model for longitudinal analysis. Outcome variables included Lysholm Score(LYS) and Tegner Activity Scale(TAS). Independent variables included gender, age, degenerative versus traumatic lesion, and number of years since surgery(YSS). Results: Of the chondral lesions treated, 53% were traumatic and 47% were degenerative. Average follow-up was 4.3 yrs(range 1 to 12). Although there was a trend favoring the outcome of men over women after 1 year, there was no significant difference in the trajectory of the plots over time. [LYS-squared=4954+435(YSS)–45(yrs-squared)+408(gender)–10.6(yrs*gender)+1.3(yrssquared*gender);p=0.88] [TAS=3.73–0.001(YSS)-0.002(yrssquared)+0.7(gender)+0.035(yrs*gender)+0.0006(yrs-squared*gender)p=0.99]. Although there was a trend favoring the outcome of traumatic over degenerative lesions between years 1 and 7, there was no significant difference in the trajectory of the plots. [LYS-squared=5539 -3.4 (age) + 456 (YSS) – 47 (yrs-squared) – 333 (djd) -85.6 (years*djd) + 8.8 (yrs-squared*djd) p=0.328] [TAS =6.0 – 0.03 (age) - 0.04 (YSS) + 0.002 (yrs-squared) – 0.539(djd) + 0.123(years*djd) – 0.011 (yrs-squared*djd) p=0.272]. Subjects were divided into two age groups, <= 45 years and >45 years. When subjects with degenerative lesions and subjects with traumatic lesions were analyzed together, there was no significant difference in the trajectory of either the LYS or Tegner scores over time by age group. However, traumatic lesions demonstrated a significant difference in the trajectory of LYS scores over time by age group. [LYS_squared = 5194 + 607 (YSS) - 58.2 (YSS squared) + 598 (age) – 336 (YSS* age) + 24.5 (YSS*age) p=0.0375].
(Cont.) Clinical Outcomes Following the Microfracture Procedure for Chondral Defects of the Knee: A Longitudinal Data Analysis
Profiles Plot of Lysholm Scores over Time by Gender Conclusions: We found no significant differences in the trajectory of outcome over time between genders, or between degenerative and traumatic chondral lesions. In addition, we have identified agedependent differences in the surgical outcome over time. Subjects with traumatic lesions demonstrated a significant difference in the trajectory of Lysholm scores over time by age group.
Cartilage Deformation in the ACL - Reconstructed Knee Authors: Samuel K. Van de Velde MD, Jeffrey T. Bingham MS, Thomas J. Gill IV MD, Louis E. DeFrate ScD, Guoan Li PhD (Boston, MA) Objective: It is poorly understood why patients after anterior cruciate ligament (ACL) reconstruction develop osteoarthritis, even though the anteroposterior (AP) stability is successfully restored. In this study, we hypothesize that ACL deficiency causes an increased structural deformation of the tibiofemoral cartilage. More importantly, we hypothesize that ACL reconstruction with a BPTB autograft does not restore the normal cartilage deformation. Methods: Eight patients (6 male and 2 female; 19-38 years old) with an acute ACL injury in one knee and the contralateral side intact participated in the study. Both knees were imaged using a specific MR sequence to create 3-D knee models. These models were digitally manipulated until their projections matched the outlines of two orthogonally placed fluoroscopic images [1], as the patient performed a single-leg lunge. Data was collected pre-operatively, and at 6 months following ACL reconstruction. The anterior laxity of the reconstructed knee as measured with the KT-1000 arthrometer was similar to that of the intact contralateral knee. Cartilage deformation was defined as the amount of penetration divided by the sum of the tibial and femoral cartilage thicknesses. A repeated measures ANOVA was used to compare the magnitude of cartilage deformation of the intact, ACL-deficient, and ACL-reconstructed knees. Significance was set at p<0.05. Figure 1
Color map of deformation for the intact and ACL-reconstructed tibia at 15° of flexion.
(cont.) Cartilage Deformation in the ACL-Reconstructed Knee
Results: ACL deficiency significantly increased the deformation of cartilage from 0° to 60° of flexion in the medial compartment, and from 0° to 30° in the lateral compartment. The maximum increase in cartilage deformation after ACL rupture occurred at 0° of flexion (18 ± 6% intact knee, 30 ± 8% ACL-deficient knee) in the medial compartment. ACL reconstruction improved the cartilage deformation throughout the range of motion. However, at 0° - 15° of flexion, a significant increase in cartilage deformation persisted in both compartments following reconstruction. The maximum increase in cartilage deformation after ACL reconstruction occurred at 0° of flexion in the lateral compartment (36 ± 5%). Conclusions: The articular cartilage of ACL-deficient knees undergoes an increased cartilage deformation. Even though ACL reconstruction improved the cartilage deformation, a persistent significant increase in cartilage deformation was observed at 0° and 15° of flexion. These findings emphasize the importance of restoring normal kinematics of the knee joint under physiological loading to prevent the development of osteoarthritis. References: Li G et al. J Bone Joint Surg Am. 2006, 88(8):1826-34.
Chondrocyte Death and Matrix Degradation Following Osteochondral Autologous Transplantation Surgery (OATS) in a Rabbit Model Authors: Lawrence V. Gulotta MD, Jonas R. Rudzki Jr MD, David Kovacevic BS, C.T. Christopher Chen PhD, Riley J. Williams III MD (New York, NY; Washington, DC) Objective: Osteochondral autologous transplantation surgery (OATS) is commonly used to treat isolated cartilage defects in the knee. Studies suggest that an impact force, similar to that used in OATS, can cause chondrocyte death and matrix degradation. The objective of this project is to determine the degree and type (necrosis and apoptosis) of chondrocyte death, and the extent of matrix degradation following OATS in a rabbit model. Methods: Twenty New Zealand White rabbits underwent unilateral OATS procedures and 10 underwent bilateral shams. OATS procedures were performed by harvesting a 2.7mm diameter, 4.0mm deep osteochondral plug from the right medial femoral condyle which was then impacted into a defect created in the left medial femoral condyle. Fifteen animals were sacrificed immediately (10 OATS0/10 Sham0 limbs), 15 sacrificed at 4 days (10 OATS4/10 Sham4 limbs). Chondrocyte viability/necrosis was determined using cell-vital staining, chondrocyte apoptosis was determined by TUNEL, Bcl-2 and M30 immunofluorescence. Cartilage degradation was determined by modified Mankin Scores based on H&E and Safranin-O staining, immunohistochemistry with Col2-3/4Cshort, and articular surface collagen birefringence under polarized light microscopy. Statistical analyses were performed using two-way ANOVA with post-hoc analysis with a significance level of p=0.05. Results: Cell vital staining showed the OATS4 group had less viable chondrocytes (51.6±11.6%) compared to the Sham4 group (74.2±5.1%,p=<0.001). A similar decrease in cell viability was found in OATS0 (63.3±7.2%) compared to Sham0 (81.0±5.0%,p=<0.001). There was a significant increase of TUNEL positive cells in OATS4 group (27.8±9.6%) compared to OATS0 and both Sham controls (all p<0.001). Bcl-2 and M30 were negative in all groups for apoptotic cells. There were higher modified Mankin Scores in the OATS groups compared to the Sham groups at both 4 days and at time zero (p=0.003 and p=0.002, respectively). The OATS4 group had positive staining for Col2-3/4Cshort with a loss of collagen birefringence at the superficial zone, indicating a disruption of collagen network due to OATS.
(Cont.) Chondrocyte Death and Matrix Degradation Following Osteochondral Autologous Transplantation Surgery (OATS) in a Rabbit Model
Figure 1
Summary of results Conclusions: Our data suggest that OATS procedures result in chondrocyte death and matrix degradation. Chondrocyte apoptosis was not seen in this model at the timepoints examined. Our findings suggest that matrix degradation is closely related to focal cell death. This suggest against indiscriminate impaction of osteochondral grafts during OATS.
Effects of Medial Meniscus Posterior Horn Avulsion and Repair on Medial Compartment Tibiofemoral Contact Area and Peak Contact Pressure Authors: Jennifer Gurske de Perio MD, MS, PT, CWS, John M. Marzo MD (Williamsville, Buffalo, NY) Objective: Avulsion of the posterior horn attachment of the medial meniscus can produce meniscus extrusion and tibiofemoral joint space narrowing, articular cartilage damage, and osteoarthritis. This study compares the tibiofemoral contact area and peak contact pressures of the native knee to knees with posterior horn meniscus avulsion and to knees in which the avulsion is repaired by sutures through a transosseous tunnel. It is hypothesized that avulsion of the posterior horn of the medial meniscus will increase peak contact pressure and decrease contact area in the medial compartment of the knee, and posterior horn repair will restore contact area and peak contact pressures to values of native knee. Methods: Eight fresh frozen human cadaveric knees had medial compartment tibiofemoral contact area and peak contact pressures measured. The posterior horn of the medial meniscus was avulsed from its insertion and knees were re-tested. The meniscal avulsion was repaired by suture through a transosseous tunnel and the knees were tested again. Results: Avulsion of the posterior horn attachment of the medial meniscus resulted in a significant increase in medial joint peak contact pressure (p=0.006), and a significant decrease in contact area (p=0.005). Repair of the avulsion resulted in restoration of the loading profiles to values equal to the native knee. Native Meniscus Avulsed Meniscus Repaired Meniscus
Lateral
Medial Lateral Medial Lateral Medial Tekscan Contact Area and Pressure Sensor Specimen Sample
Conclusions: Posterior horn medial meniscal root avulsion leads to deleterious alteration of the loading profiles of the medial joint compartment. This study stands in support of the theory that this condition puts the knee at risk to medial degenerative changes, and efforts should be made to surgically correct the pathology to restore more normal biomechanics to the knee. The repair technique described restores the ability of the medial meniscus to absorb hoop stress and eliminate joint space narrowing, possibly decreasing the risk of degenerative disease.
(cont.) Effects of Medial Meniscus Posterior Horn Avulsion and Repair on Medial Compartment Tibiofemoral Contact Area and Peak Contact Pressure
References: 1. Lee, SJ et al. AJSM 2006. Marzo, JM et al. AJSM 2007 (Accepted for publication). Pagnani, MJ et al. Arthroscopy 1991. Paletta, GA et al. AJSM 1997. Richmond, JC et al. Arthroscopy 1988.
Acknowledgements: Thanks to Craig Howard, BS and Cathy Buyea, MS.
The Relationship Between Medial Meniscus Tear Morphology and Chondral Changes Within Medial and Lateral Compartments of the Knee Authors: Sarah Henry BSc, Randy Mascarenhas MD, Brian Forsythe MD, James J. Irrgang PhD, PT, ATC, Christopher D. Harner MD (Pittsburgh, PA) Objective: The purpose of this prospective cohort study was to define the relationship between medial meniscus tear morphology and articular cartilage lesions of the knee. We hypothesized that meniscus tears that disrupt the hoop stresses will increase cartilage wear in the medial and lateral compartments of the knee. Methods: The medial meniscus tear pattern along with modified Outerbridge and Noyes scores for the medial and lateral compartments of the knee were prospectively recorded in patients undergoing arthroscopic knee surgery for a medial meniscus tear. Patients with an ipsilateral ligament injury, lateral meniscus tear, previous knee surgery or Fairbanks changes greater than grade 3 were excluded. The senior author performed all surgeries and graded all pathology reported. Results: 103 patients were included in the study (26 female, 77 male). The mean age was 47 years (range 14-72). Six medial meniscus tear patterns were observed including: 25 horizontal, 26 degenerative, 11 vertical or bucket-handle, 30 radial, 21 root, and 11 flap tears. Patients with radial (p<0.05) or root (p<0.001) tears had more severe cartilage lesions on the medial femoral condyle compared to vertical and bucket-handle tears. Root tears also had more severe cartilage lesions on the medial tibial plateau when compared to vertical and bucket-handle tears (p<0.01). More specifically, root tears were noted to have greater wear on the nonmeniscal weight bearing zone (p<0.001) and the tibial spine (p<0.01) region of the medial tibial plateau when compared to vertical and bucket-handle tears. Radial tears had more severe cartilage lesions in the lateral compartment when compared to horizontal and degenerative tears (p<.05) and vertical and bucket-handle tears (p<0.01). Vertical tears had little or no wear in all compartments with horizontal, complex, flap, radial, and root tears having progressively more severe cartilage lesions on the medial femoral condyle and medial tibial plateau compared to vertical tears (p<0.05). Conclusions: The role of meniscal injury in the pathogenesis of articular cartilage degeneration is poorly understood. This study demonstrates a significant relationship between medial meniscus tear morphology and the location and severity of cartilage lesions within medial and lateral compartments of the knee. Further analysis of the relationship between meniscus tear morphology and cartilage wear may optimize surgical decision making with respect to repair versus meniscectomy. Research support for this project provided by Biomet
The Non-Operative Treatment of Degenerative Meniscal Tears Authors: Michael Maloney MD, Kenneth Morse MD, Omar Darr MD, Kevin Tu MD, Kenneth E. DeHaven MD (Rochester, NY; Mequon, WI; Chicago, IL) Objective: The treatment of degenerative meniscal tears continues to be a topic of debate among orthopaedic surgeons. While historical studies of total meniscectomy have reported generally poor outcomes, more recent studies of partial meniscectomy have had mixed results. There is, however, a paucity of literature on the non-operative treatment of these lesions. The objective of this study was to evaluate the effectiveness of a physical therapy protocol on the treatment of degenerative meniscal tears. Methods: Patients with minimal osteoarthritis and without mechanical symptoms were eligible for the study. Twenty-eight patients with presentation, examination, and radiographic findings consistent with a degenerative meniscal tear were enrolled in a six-week course of physical therapy. After six weeks, all patients were offered surgical intervention. Those who elected surgical intervention underwent arthroscopy at an average of 1.7 months after completion of physical therapy. Upon initial presentation, and at the six-week and two-year follow-up, all patients were provided an International Knee Documentation Committee (IKDC) scoring questionnaire. Results: At six weeks, 16 patients (57.1%) elected to continue non-operative treatment while the remaining 12 patients underwent arthroscopy and partial meniscectomy. The IKDC scores after six weeks of physical therapy were significantly higher for the patients who declined surgery than for those who elected to have surgery. There was no significant difference between the two groups regarding anatomic alignment, location of tears, or strength testing at presentation and six weeks. At a mean follow-up of 31.7 months, IKDC scores were available for 22 patients (78.6%). This included 11 patients treated conservatively and 11 arthroscopy patients. There was no significant difference in IKDC scores between the two groups at 31.7 months. Conclusions: This study provides support for the initiation of non-operative treatment for select patients with degenerative meniscal tears. Over half of patients in this study were able to avoid surgery with only six weeks of therapy. Moreover, the majority of these patients remained improved over the 31 month follow-up time period.
Meniscal Allograft Size: Can it Be Predicted by Height and Weight? Authors: Geoff Van Thiel MD, Nikhil N. Verma MD, Allison G. McNickle BA, Adam B. Yanke BS, Jack Farr II MD, Brian J. Cole MD, MBA (Chicago, IL; Indianapolis, IN) Objective: Accurate allograft sizing is required for successful results following meniscal transplantation. The purpose of the current study is to determine if height, weight and gender can be accurately used to predict proper meniscal allograft size. Methods: Data was obtained from Allosource (Centennial, CO) regarding meniscal size and patient factors from meniscal donors. Donor height, weight, sex, age, and anatomic meniscal dimensions were recorded for 930 donor menisci in 664 patients. Multivariate regressions were completed using gender, height and weight as independent variables and lateral meniscus length, lateral meniscus width, medial meniscus length and medial meniscus width as dependent variables. The regression formulas were then reapplied to the data in order to produce estimated meniscus dimensions based on donor height, weight and gender. Predicted meniscal size was then compared to actual meniscal size and the accuracy of results compared to current measurement techniques. Results: Regression forumulas demonstrated the ability to predict meniscal size based on gender, height and weight with standard deviations equal to or less than current radiographic techniques (6.40 – 8.26 % S.D.). Average differences between predicted size and actual size ranged between 5.21-6.32% for length and 5.13-5.65% for width. Patient height was found to be a much more powerful predictor of meniscal size than patient weight. In order to eliminate the confounding variable of bilateral correlations all analyses were repeated using only one menisci compartment per donor and no significant change in results was noted. Conclusions: Meniscal allograft size can be predicted using gender, height and weight with a level of accuracy similar to current radiographic techniques.
Patellar Height after High Tibial Open Wedge Osteotomy Authors: Robert F. LaPrade MD, PhD, Fernando Barrera Oro MD, Connor G. Ziegler BS, Onur Hapa MD, Coen A. Wijdicks MSc (Minneapolis, MN) Objective: The controversy surrounding alteration in patellar height represents the primary issue with respect to surgical difficulties and outcomes following failed HTO. While a decrease in patellar height has been substantiated with regards to closing wedge proximal tibial osteotomies, it has not been widely verified among opening wedge osteotomy procedures. Methods: Patients who underwent an opening wedge proximal tibial osteotomy were prospectively followed. All patients were clinically and radiographically evaluated preoperatively and postoperatively in order to assess simultaneous pathology. Patellar height was substantiated using lateral radiographs via a digital radiograph image viewer. Preoperative, immediate postoperative, three month and six month lateral knee AP radiographs were measured for patellar height for each patient. The Insall-Salvati Index, the Blackburne-Peel Index and the Caton-Deschamps Index. In addition, a method described by Miura and Kawamura was utilized. The technique for drawing the line perpendicular to the axis of the tibia was modified in our study from the original Miura and Kawamura method. Results: 84 patients, 67 males and 17 females (85 knees) underwent a proximal tibial opening wedge osteotomy. The mean age was 35 years at the time of surgery. Change in patellar height was significant from preoperative to immediate postoperative assessment and from preoperative assessment to both 3 months and 6 months of follow-up utilizing all four methods (Figure).
Ratios of the four measurements
(cont.) Patellar Height after High Tibial Open Wedge Osteotomy
Conclusions: Patellar descent has been theorized to result from shortening of the patellar tendon. There have been no recent studies incorporating four different measuring techniques including a method using a femoral reference point. Accordingly, we sought to substantiate the patellar height after opening wedge osteotomy by utilizing different published methods to measure each patient’s preoperative and postoperative radiographs. Unlike prior studies, we also observed the changes produced after three and six months of follow up. Proximal tibial opening wedge osteotomies do decrease patellar height and this effect happens within the first three postoperative months. The shortening of the patellar tendon may affect future surgeries and needs to be evaluated as part of the preoperative assessment in these patients.
Quantification of Posterolateral Knee Radiographic Landmarks Authors: Coen A. Wijdicks MSc, Sean D. Pietrini BS, Bryan M. Armitage MSc (Minneapolis, MN) Objective: During intra-operative procedures, it can be difficult to locate the attachment sites of the fibular collateral ligament (FCL), popliteus tendon (PLT), and popliteofibular ligament (PFL) in the absence of specific radiographic guidelines. Our purpose was to establish radiographic landmarks for the femoral and fibular attachment sites of the FCL, PLT, PFL, and lateral gastrocnemius tendon (LGT). Methods: 11 nonpaired specimens were dissected. 2mm metal spheres were imbedded within the centers of the bony attachments. Radiographic measurements were made in a picture archiving and communication system program (Figure). Perpendicular distances to a line intersecting the most proximal aspects of the tibial plateaus were measured for the tibial and fibular based structures. A reference line was drawn along the posterior femoral cortex, and perpendicular distances between this reference line and the marked attachment sites were quantified. A second reference line was drawn perpendicular to the posterior cortex and intersecting the posterior point of Blumensaat’s line. To examine interobserver reliability, three examiners were assigned to independently measure blinded radiographs. Single-measure intraclass correlation coefficients (ICCs) were used to determine variability.
(cont.) Quantification of Posterolateral Knee Radiographic Landmarks
Figure. Illustration (A) and lateral knee radiograph (B) demonstrating the placement of the femoral reference lines. Illustration (C) and lateral knee radiograph (D) demonstrating the technique to identify the center of the tibial diaphysis. Results: The ICC was 0.972, indicating a high level of reliability among the three examiners. The average FCL attachment on the femur was 4.3 mm from the lateral epicondyle in the anteroproximal direction, 14 mm from the PLT attachment, and 9.6 mm from the LGT attachment. The average distance from the origin of the PLT to the lateral epicondyle was 12.1 mm. The average PLT origin site was 0.9 mm posterior to the posterior cortex extension and 25.8 mm distal to the line drawn through Blumensaat’s point. The distal FCL attached 13.9 mm distal to the PFL attachment. The average FCL attachment was 5.7 mm posterior to the fibular diaphyseal axis and 6.0 mm distal to the line intersecting the most anterior point of the fibular head, compared to 9.5 mm posterior and 6.6 mm proximal for the location of the PFL attachment.
(cont.) Quantification of Posterolateral Knee Radiographic Landmarks
Conclusions: This study provides a reliable and transferable protocol for identifying posterolateral attachment sites on radiographic images. We believe that the integration of these two approaches will allow not only for a higher degree of precision in quantifying the attachment sites radiographically but also for more consistent intraoperative and post-operative assessments of anatomical reconstructions. References: LaPrade RF, et al., Am J Sports Med. 31:854-860, 2003.
The Effect of Passive Knee Flexion on Tension in the Medial Patellofemoral Ligament Authors: Scott M Levin MD, Stephen J. Nicholas MD, Aruna M. Seneviratne MD, Ian J Kremenic ME, Karl F Orishimo MS, Malachy P. McHugh PhD, Timothy F. Tyler MS, PT, ATC, PRO Mehul Shah MD (Kisco, New York, Scarsdale, NY) Objective: The treatment for patellar instability includes nonoperative management, as well as medial patellofemoral ligament (MPFL) repair or reconstruction. The goal of this study was to determine the effect of passive motion and change in knee flexion angle on the tension exerted on the MPFL. This information could help guide rehabilitation after MPFL repair, reconstruction, or nonoperative treatment of patellar dislocation Methods: A load cell was fixed in series with the MPFL to measure the tension on the MPFL during passive motion in six fresh-frozen cadaver knees. A 2 kg weight was applied to the quadriceps tendon with the knee in extension and then the quadriceps tendon was clamped to allow passive force to increase with knee flexion (simulating the tension due to normal quadriceps stretch). The direction of pull of the quadriceps tendon relative to the patellar tendon was set at 17 degrees for each specimen to simulate a normal female Q angle. A suture was placed through the MPFL of each specimen and tied to a force transducer. A pretension of approximately 2 N was placed on the ligament with the knee set at 45 degrees. Tension in the MPFL and knee flexion angle were recorded continuously as the knee was extended from 45 degrees and then fully flexed from the same point. The Friedman test with post hoc Wilcoxon signed-rank tests were used to test whether knee flexion affected tension in the MPFL. The threshold for statistical significance was set at P < 0.05.
(cont.) The Effect of Passive Knee Flexion on Tension in the Medial Patellofemoral Ligament Figure 1
Suture through MPFL attached to load cell Results: All MPFL's experienced increased tension moving from 45 degrees to full extension; Force increased from an initial tension of 1.9 +/- 0.7 N at 45 degrees to 3.8 +/- 1.0 N at 28 degrees (P<0.05). Minimal tension was measured in all MPFL's when the knee was flexed from 45 degrees to 100 degrees. MPFL tension increased markedly in three specimens as the knee was flexed beyond 100 degrees (11.1 N at 124 degrees, 8.9 N at 121 degrees, 6.7 N at 133 degrees). Conclusions: There was minimal tension in the MPFL as the knee was extended from a starting point of 45 degrees and flexed to 100 degrees. Based on this data and previous biomechanical studies, MPFL repair and reconstruction may withstand the small forces as a result of passive motion in the immediate postoperative period. Future studies involving cyclical loading are warranted to confirm this conclusion.
Blocking Myostatin with Suramin Improves Skeletal Muscle Healing Authors: Masahiro Nozaki MD, Yong Li MD, PhD, Jinhong Zhu MD, Fabrisia Ambrosio PhD, Kenji Uehara MD, PhD, Freddie H. Fu MD, Johnny Huard PhD (Pittsburgh, PA) Objective: Muscle injuries are very common musculoskeletal problems in sports medicine. Although current therapies such as RICE (rest, ice, compression, and elevation) are the norm for treatment, complete functional recovery is hindered by the development of scar tissue formation. Myostatin, a negative regulator of muscle growth, has been shown to stimulate fibrosis in skeletal muscle.1 Thus, we have focused the current study on the prevention of scar tissue through the down-regulation of myostatin by suramin, an anti-fibrotic agent which is already approved by Food and Drug Administration (FDA). Using an animal (murine) model of muscle contusion, we examined, 1) whether suramin can block the effect of myostatin and promote myogenic differentiation of myoblast cells in vitro and 2) whether suramin treatment enhances muscle regeneration and reduce fibrosis by down-regulating myostatin expression in vivo. Methods: In vitro: Myoblast cells were cultured with low-serum medium containing different concentrations of myostatin (0 and 1 μg/ml) and suramin (0, 1, and 25 μg/ml) to induce myogenic differentiation. In vivo: The muscle contusion was made on the tibialis anterior (TA) muscle of each mouse. Two weeks after injury, different concentrations of suramin (0 and 2.5 mg) were injected intramuscularly (n=20 mice/ group). At different time points (0.5, 1, 2, 10, and 14 days after injection), mice were sacrificed and cryosections of TA muscle were analyzed histologically. Results: In vitro: Myostatin treatment significantly inhibited the myogenic differentiation of myoblasts. However, suramin treatment significantly blocked myostatin’s effects and moreover suramin treatment stimulated the fusion of myoblasts in a dose-dependent manner in the presence of myostatin (Fig. 1). In vivo: Suramin (2.5 mg) injection demonstrated a significant increase in the number of regenerating myofibers (Fig.2) and reduction of fibrotic area (Fig.3) when compared with the control group (0 mg). Furthermore, suramin injection effectively inhibited the expression of myostatin in the injured muscle (Fig. 4).
(cont.) Blocking Myostatin with Suramin Improves Skeletal Muscle Healing
(cont.) Blocking Myostatin with Suramin Improves Skeletal Muscle Healing
Conclusions: Suramin improved skeletal muscle healing by enhancing regeneration and reducing fibrosis after contusion injury. Furthermore, a decrease the expression of myostatin in injured muscle treated with suramin may reveal a possible mechanism by which suramin improves skeletal muscle healing after injury. Our findings may contribute to the development of progressive therapies for muscle injury. References: Zhu J, Li Y, Huard J. Relationships between transforming growth factor-beta1, myostatin, and decorin: implications for skeletal muscle fibrosis. J Biol Chem. Aug 31 2007;282(35):2585225863. Acknowledgements: The authors are grateful for technical assistance from Maria Branca, Jessica Tebbets, Aiping Lu. Funding support was provided by Department of Defense (W81XWH-06-1-0406 awarded to Dr. Johnny Huard, Ph.D.), the William F. and Jean W. Donaldson Chair at the Children’s Hospital of Pittsburgh, and the Henry J. Mankin Endowed Chair in Orthopaedic Surgery at the University of Pittsburgh.
The Classification and Mechanism of Olecranon Stress Fractures in Baseball Throwers Authors: Kozo Furushima MD, Yoshiyasu Itoh MD, Akihito Tsujino MD (Tatebayashi Gumma, Japan) Objective: Stress fracture of the olecranon caused by repetitive throwing had infrequently been reported. It has been believed that triceps overload might have caused the stress fracture of the olecranon. And another report shows that it occurs because of valgus extension overloads in the acceleration phase, not because of extensor overloads. It fs still unknown whether this injury is due to the pull from the triceps insertion or to the valgus-extension stress . We tried to classify the direction of the fracture line and examined the mechanism from analysis of olecranon stress fracture. We describe the classification and the mechanism of injury of olecranon stress fracture in baseball throwers. Methods: We examined the olecranon stress fracture of 126 baseball players treated in our hospital from 1987 to 2007. Fifty five elbow of adolescent type (mean age, 14 years) were diagnosed as olecranon epiphyseal stress fracture, and 71 elbow of adults type (mean age, 19 years) were diagnosed as olecranon stress fracture. We classified a feature of run of the fracture line by X-plain, CT, MRI of all examples, and guessed a mechanism injury of olecranon stress fracture. Results: We classified 5 types by the direction of the fracture line. (Figure 1) a. Physeal type (40.2%): Epiphyseal fracture of the olecranon. b. Classical type (34.5%): Oblique fracture in AP view of the olecranon, the fracture line run from articular surface to proximal-dorsal of ulna in lateral view. c. Transitional type (13.8%): Transverse fracture of the olecranon in AP view of the olecranon, the fracture line run from articular surface to proximal-dorsal of ulna in lateral view. d. Sclerotic type (9.2%): X-plain findings demonstrated no evidence, MRI demonstrating sclerotic at the fracture site. e. Distal type (2.3%): The fracture site appear distal part of trochlear notch About 80% of this series had medial elbow instability.
(cont.) The Classification and Mechanism of Olecranon Stress Fractures in Baseball Throwers (cont.) The Classification and Mechanism of Olecranon Stress Fractures in Baseball Throwers
Figure 1 Conclusions: Triceps tendon inserts posterior dorsal surface of the olecranon, not tip and medial surface of olecranon. In every types, the fracture line starts from ulnar side and runs to distal radial direction in AP view, and from articular surface to proximal-dorsal of ulna in lateral view. In our opinions, valgus and extension overloads of the elbow during throwing can ensue chronic medial instability followed by extension type of the olecranon fracture. We suggest that this injury should be considered to occur by valgus-extension overloads in the acceleration and follow through phase.
Growth Factors Release After Arthroscopic Acromioplasty Authors: Pietro Randelli MD, Giada Dogliotti BS, Fabrizio Margheritini MD, Paolo Cabitza MD, PhD, Massimiliano M. Corsi MD, Matteo Denti MD (Milan, Rome, Italy) Objective: Acromioplasty represents one of the most popular procedure in shoulder surgery. It can be performed in association with rotator cuff repair, in order to protect the sutures and to avoid a cuff re-rupture for recurrence of the impingement syndrome. Recently it has been postulated that after acromioplasty a variety of Growth Factors (GF) can be released from the acromial cancellous bone over the cuff repair. GF are proteins that serve as signalling agents for cells, and can support tissue healing. The aim of this study is to demonstrate the presence of GF in the subacromial space after arthroscopic acromioplasty. Methods: In our series 23 patients were submitted to shoulder arthroscopy for sub-acromial patologies. After acromioplasty a vaacum drain was placed in the subacromial space, under the acromion. The portals were sutured. 15 minutes after the end of the procedure a sample of at least 3 ml of fluid from the shoulder was obtained. At the same time another sample of 3 ml of the patients venous blood was obtained as control. Assays: concentrations of GF in fluids collected were determined using enzyme-linked immunosorbent assay (ELISA). Each of our fluids was evaluated for platelet-derived growth factor-AB (PDGF-AB), fibroblast growth factor basic (FGF-b) and transforming growth factor beta 1 (TGF-β1). A monoclonal antibody specific for interesting molecules has been pre-coated onto a microplate and between immune-reaction the substrate develops color in proportion to the amount of growth factors bonds in the initial step. The color develop is stopped and the intensity of the color is measured. The measurement sensitivity of TGF-β1 up to 1.7, about PDGF-AB up to 0.9 pg/mL and FGF-basic sensitivity is typically less than 3 pg/mL. Results: Our data show that TGF-β1 was higher in subacromial space than in blood: 14798 (+ 4448.8) pg/ml vs. 8685.7 (+ 4556.1) pg/ml [p=0.0001]. As well PDGF-AB was higher in subacromial space than in blood: 147.08 (+ 80.8) pg/ml vs 96.3 (+ 40.3 )pg/ml [p=0.02]. Also FGF-basic was higher in subacromial space than in blood: 488.55 (+ 221.73) pg/ml vs 10.29 (+ 11.14) pg/ml ƒËp< 0.0001ƒÍ. Conclusions: A high level of expression of Growth Factors is present in the subacromial space after acromioplasty. Further studies are required to fully understand their potential in tissue healing. The results of the present study point out the need for further investigation of the up-regulation of such molecules in patients after shoulder surgery.
An RCT Comparing the Effectiveness of Rotator Cuff Repair with or without RESTORE for Patients with Moderate to Large Rotator Cuff Tears Authors: Dianne Bryant PhD, Robert B. Litchfield MD, FRSC, Darren Drosdowech MD, FRCSC, Richard Holtby MD, FRCSC, Kevin Willits MD, FRCSC, Jaydeep K. Moro MD, FRCSC, Scott Mandel DM, FRCSC, Gord Guyatt MD (London, Toronto, Hamilton, Canada) Objective: To compare failure rates, quality of life, function, strength, ROM and general health for patients with rotator cuff repair with or without Restore. Methods: This was a multi-center randomized parallel groups pilot study. Randomization took place in the OR by central call-in after the surgeon repaired the tear. Patients and data assessors were blind to group allocation. Clinical outcomes included Western Ontario Rotator Cuff Index (WORC), ASES, Constant, SF-36, range of motion, and strength. Patients were assessed at 6 weeks, 3, 6, 12, 18 and 24 months post-operative. Primary endpoint was 1 year post-surgery. Results: Ninety-six consented to participate; 62 patients were eligible and randomized (34 Restore, 28 control). Demographic characteristics were similar between groups. All patients had a full thickness tear of the supraspinatus; 6 Restore and 8 control patients had concomitant tears of the infraspinatus tendon. Tear size was similar between groups. A positive tangent sign (muscle atrophy) was evident in 9 Restore patients and 8 control patients. The highest grade of fatty infiltration was Grade II (fat present; more muscle than fat) found in 13 Restore and 14 control patients. No patient had a tear of the subscapularis or teres minor and biceps pathology was balanced between groups. Following surgical repair, 19 Restore and 17 control patients had a complete repair; six in each group had a remaining defect between 5 and 10mm; no patient had a remaining defect greater than 10mm. At 1 year post-operative, 16 Restore patients and 16 control patients had a full-thickness defect of the supraspinatus (RR=0.80 95%CI 0.52 to 1.24, p=0.32); 5 of these tears extended into the infraspinatus (3 Restore, 2 control). There was no statistically significant difference between the Restore and control group in WORC score (77.7 (SE=3.2), 83.1 (SE=3.5), diff = -3.7 (95%CI -13.1 to 5.8), p=0.44), forward elevation (147.7 deg (SE=4.6), 150.8 deg (SE=5.0), diff = -3.1 deg (95%CI -17.1 to 10.8), p=0.65), external rotation (48.8 deg (SE=3.0), 56.3 deg (SE=3.2), diff = -7.5 deg (95%CI -16.3 to 1.4), p=0.10) or strength (13.8 lbs (SE=1.3), 13.4(SE=1.5), diff = -0.38 lbs (95%CI -3.7 to 4.5), p=0.85). Conclusions: Short-term clinical outcomes appear similar between groups but do not exclude the possibility that important differences between groups exist. A larger study is required to definitively determine the effectiveness of Restore to improve patient-important outcomes following rotator cuff surgery.
Research support provided by CIHR/DePuy PAT – CHECK WITH AUTHOR RE: REseach Support Clarify co. names ???
Arthroscopic Repair of Irreparable Rotator Cuff Tears Using Graft Jacket® Allograft: A 2 Year Follow-up Authors: Joseph P. Burns MD, Jason Higgins MD, James L. Bond MD, Steven J. Snyder MD (Van Nuys, CA; Thibodaux, LA; Norman, OK) Objective: Although current techniques in rotator cuff repair offer successful results in the majority of cases, there are still many instances where tendon repair is not possible. There are few surgical alternative treatments for such cases. Traditionally surgical management has included debridement only, muscle transfers, various allo- and autografts, and shoulder replacement. These techniques have been largely unsuccessful and can be associated with significant morbidity. The objective of this study was to evaluate the 2year results of patients with irreparable rotator cuff tears which were treated with arthroscopic placement of GraftJacket® allograft acellular dermal matrix. Methods: Between March 2003 and March 2004, thirteen patients with a previously documented massive, contracted, immobile rotator cuff tears were treated with arthroscopic placement of a GraftJacket® allograft by a single surgeon (SJS), bridging the rotator cuff defect with circumferential suturing. Thirteen patients were followed for greater than 2 years, noting range of motion, strength and activity improvement. Additionally, all patients were evaluated by the modified University of California Los Angeles (UCLA) scoring system, the Constant scoring system, and Simple Shoulder Test. Results: At mean follow-up time of 32.6months (range, 27-45 months), 12 of 13 patients were satisfied with the procedure. The mean modified UCLA score increased from 18.4 preoperatively to 29.8 postoperatively (P-value = 0.0001). The Constant score increased from 53.8 preoperatively to 87.3 postoperatively (P = 0.0001). Statistically significant improvements were also seen in pain, forward flexion, and external rotation strength. Twelve of thirteen displayed full incorporation of the graft into the native tissue as documented by postoperative MRI scans at one year. All but one patient’s preoperative pain improved. Shoulder motion and function also improved significantly. Only one of the thirteen patients failed between the first and second year. There were no other significant complications with this procedure. Conclusions: Our study supports the hypothesis that GraftJacket® allograft is a viable solution for surgical salvage in select cases of massive, irreparable rotator cuff pathology. Using minimally-invasive technique, this treatment option may provide patients with decreased pain and increased function despite a previously irreparable rotator cuff tear. Research support provided by Wright Medical Technology.
Outcome of Workers’ Compensation Patients Following Arthroscopic FullThickness Rotator Cuff Repair Authors: Dana P. Piasecki MD, Brian J. Cole MD, MBA, Nikhil N. Verma MD, Gregory P. Nicholson MD, Sanjeev Bhatia BS, Nicole Boniquit BS, Anthony A. Romeo MD (Chicago, IL) Objective: Outcomes following rotator cuff repair in workers compensation patients are generally reported to be inferior to the general population. The purpose of this study is to evaluate the outcome of arthroscopic rotator cuff repair in workers compensation patients and to identify prognostic factors which may help predict the ability to return to pre-injury level of work. Methods: A retrospective cohort of 78 consecutive adult patients (mean age 54.9 +/- 8.2 years) were evaluated at a minimum 1 year follow-up following arthroscopic repair of fullthickness rotator cuff tears. Exclusion criteria included patients presenting with partialthickness or irreparable tears, subscapularis involvement and/or revision surgery. Follow-up evaluation was performed by a single examiner and included range of motion (ROM), outcome scores (American Shoulder and Elbow Surgeons Score, ConstantMurley, Visual Analog Score, and Simple Shoulder Test), and dynamometer strength testing. Multiple variables including preoperative work level, gender, medical comorbidities, alcohol or tobacco use, and tear size were recorded. Contingency table analysis was used to identify significant associations between these variables and return to work at preoperative levels, time to maximum medical improvement (MMI) and failure of repair requiring revision. Results: Patients were evaluated at an average follow-up of 2.5yrs (range 1.0-6.4, sd 1.1). 89.7% of patients returned to their preoperative level of work, at an average time to MMI of 7.6 +/- 2.6 months. 5.1% of patients had failure of their repairs requiring revision. Preoperative work level, smoking status, gender and tear size did not influence return to work status, MMI or failure rate in this population. A history of preoperative alcohol use (>6 beers/wk) was significantly associated with not returning to preoperative work levels following surgery (p=0.011). Nondiabetics and patients who did not drink alcohol (<6 beers/wk) were significantly less likely to have repair failure requiring revision (p=0.012 and 0.009, respectively). Conclusions: Compensable patients undergoing arthroscopic full-thickness rotator cuff repair return to preoperative levels of work in the majority of cases, regardless of preoperative work level, smoking status, gender or tear size. Diabetes and reported alcohol use may predict a less likely return to work and a higher failure rate in these patients.
The Relationship of Traction Force, Traction Time and Nerve Conduction Abnormalities During Hip Arthroscopy Authors: Scott D.M. Wotherspoon MD, Kevin Willits MD, FRCSC, Timothy J. Doherty MD, FRCPC (London, Canada) Objective: The purpose of this study is to investigate the relationships of traction force, traction time, and hip distraction to the development of nerve conduction abnormalities during hip arthroscopy. Methods: Thirteen patients underwent hip arthroscopy in the supine position. Traction forces were measured using a load-cell force transducer. Distraction of the hip joint was assessed using fluoroscopy. Nerve conduction studies of the tibial nerve were performed using a stimulator and surface electrodes measuring the latency of the Hoffmann reflex (Hlat reflex). Measurements of the traction force, distraction of the hip, and nerve conduction studies were performed and documented at baseline, at the time of traction application, and every fifteen minutes following. Upon completion of the procedure, traction was released and nerve conduction studies were immediately performed and repeated in the recovery room one hour post-traction. Results: Nerve conduction abnormalities were obtained in all thirteen patients upon application of traction. Six patients lost the Hlat reflex during the procedure, and the remaining seven patients all had delayed conduction of the Hlat reflex over time. At one-hour post-traction, the Hlat reflex was documented in all thirteen patients (mean 32+/-3 ms) and approached that of the baseline, although remained significantly different (p<0.01). Clinically, one patient in the lost Hlat reflex group had a neurapraxia post-operatively. The mean initial traction force at time of application for all patients was 97+/-28 lbs. The mean initial traction force of the lost Hlat reflex group and retained Hlat reflex group was 104+/-32.6 lbs and 91+/-24.1 lbs, respectively (p=0.44). The mean initial hip distraction at time of application of traction for all patients was 8.8+/2 mm. The mean initial distraction of the lost Hlat reflex group and retained Hlat reflex group was 9.6+/-1.4 mm and 8+/-2.2 mm, respectively (p=0.15). Conclusions: Traction during hip arthroscopy is associated with significant nerve conduction abnormalities in the immediate post-operative period. Six of thirteen patients had complete loss of the Hlat reflex during the procedure, one of these patients exhibiting clinical neurapraxia post-operatively. Although no significant differences were found in the small sample sizes comparing those patients with lost and retained Hlat reflexes, those with lost Hlat reflexes had greater distraction of the hip during the procedure.
Surgical Anatomy and Classification of Proximal Hamstring Avulsions and Its Correlation to a Surgical Algorithm Authors: James P. Bradley MD, Mathew Pombo MD, Steven B. Cohen MD (Pittsburgh, Philadelphia, PA) Objective: Proximal hamstring avulsions from the ischium are becoming more frequently recognized secondary to their disability when treated nonoperatively. The acute repair of these injuries is becoming more prevalent. The purpose of this study is to describe the first classification system of proximal hamstring avulsion injuries and how it can be applied to a standard surgical algorithm. Methods: Thirty proximal hamstring repairs from 2005 until present were enrolled in this study. Standard surgical dissection and repair was performed as described previously. Anatomical evaluation of cases was performed and correlated to preoperative MRI. A surgical algorithm was developed and correlated with anatomic findings to identify and classify proximal hamstring avulsions. Results: A new classification system was developed and groups proximal hamstring avulsions into one of five types. Type I injuries involved one tendon. A subset of these are A and B, with IA retracted less than 2cm and IB retracted greater than 2cm. Type II injuries involve two of the three proximal hamstring tendon insertions. The subsets of Type II injuries are IIA and IIB and are based on tendon retraction of less than 2cm or greater than 2cm, respectively. A unique and rare type II injury is the IIC injury. It is a two tendon injury described as an inverted cone variant. Type III avulsions are apophyseal avulsions and included a type IIIA and type IIIB based on retraction less than or greater than 2cm, respectively. Type IV injuries are three tendon avulsions and include a type IVA and type IVB subset based on retraction of less than or more than 2cm, respectively. Type V is an acute on chronic injury of any of the above patterns. Preoperative MRI findings when correlated to surgical findings revealed that in every one or two tendon injury with greater than 2cm of retraction on MRI there was one more tendon involved at surgery than initially predicted. From our experience as injuries increase from type I-V, and from subsets A to C in each type, they become more technically demanding to surgically repair.
(cont.) Surgical Anatomy and Classification of Proximal Hamstring Avulsions and Its Correlation to a Surgical Algorithm
Classification of proximal hamstring avulsions Conclusions: This is the first classification system that has been described for proximal hamstring avulsions in the literature. It is an anatomic classification designed from the correlation of surgical findings to those on pre-operative MRI and can be effectively used to assess injury severity, predict surgical intervention, and predict surgical complexity in the setting of repair.