ORIGINAL ARTICLE JK PRACTITIONER LONG TERM RESULTS OF SURGICAL TREATMENT

ORIGINAL ARTICLE JK-PRACTITIONER LONG TERM RESULTS OF SURGICAL TREATMENT FOR PESCAVUS M A Mansoor FRCS Ed, FRCS Glasg, MSc Orth ___________________________________________________________ ( Abstract: Pes cavus is a complex foot deformity of diverse etiologies. Its treatment continues to challenge the orthopaedic surgeons due to multiple combinations of clinical deformities and the varying patterns of muscle imbalance. An assortment of surgical procedures are used to relieve symptoms, correct the deformity and prevent recurrence. The results of surgery were assessed in 33 patients with a mean follow up of 65 months. Excellent to good results were shown by 90% of patients who had soft tissue surgery only, 65% with metatarsal osteotomy, 57% with Cole's dorsal nndtarsal wedge arthrodesis and 40% with Jahss s tarsometatrsal truncated wedge arthrodesis. It is concluded that soft tissue procedures are most useful for correction of flexible deformity especially in younger patients. Bony procedures should be performed for rigid deformity in skeletaly mature patients. Proximal metatarsal osteotomy give better outcome as compared to other midfoot osteotomies/arthrodeses. ' " ■ ■ ■ ■ ■ J " " ^ Key words: Pes cavus, osteotomy, arthrodesis JK-Practitioner 2001; 8 (4): 215-218 INTRODUCTION Pes cavus is defined as an increase in longitudinal arch height due to a dropping of the anterior arch with plantar flexion of the forepart of the foot, with a variable amount of claw-toes. Steindler (1921)1. The pathomechanics and natural history of pes cavus deformity vary with aetiology. It is now generally recognised that the deformity is multifactorial and there is no single procedure which would be universally applicable to correct it. Results of surgical procedures for Pescavus are difficult to evaluate and compare because of variety and combinations for procedures as well as lack of uniformity in outcome criteria This study assessed the results of commonly used surgical procedures for correction of the cavus component, according to the modified American Orthopaedic Foot Society Clinical Rating system for midfoot. (AOFAS) Material and Methods This retrospective study looked at 41 patients who were identified to have had corrective surgery for cavus component of PES CAVUS deformity at the Royal National Orthopaedic Hospital, Stanmore, UK between 1990 and 1998 33 patients were not available for the study. The patients were sent a questionaire and were later examined in the review clinic. A modification of AOFAS rating system was devised for better representation of Pescavus deformity. The total score was 90. The scores were grouped as Excellent (73-90), Good (59-72), Fair (46-58) and Poor (0-45). A successful treatment of pescavus was defined as relief of pain, correction of deformity and restoration of function by achieving and maintaining a balance foot. The patients were From the Department of Orthopaedics And Trauma Surgery Prince Charles Hospital Merthyr Tydfil. Uk (Mansoor) Received June 2001 Accepted September 2001 Correspondence: Mr M A Mansoor. Trust Specialist, Trauma And Orthopaedics, Prince Charles Hospital, Merthyr Tydfil CF47 9DT. Uk asked to rate the results of surgery on a scale of 0-10 where 0 was marked as poor and 10 as excellent. Where the result was rated less than 5, a further explanation was sought from the patient about the basis for lower rating. These results were grouped as excellent, good, fair and poor, (table 2). Table 1. Modified American Orthopaedic Ankle & Foot Society Midfoot Scoring System (Total 90) Vol. 8 No. 4, October - December 2001 215 JK-PRA CTITIONER (1-18 years). 6 patients scored excellent, 5 achieved good, 4 gave fair result and 5 patients had poor result on the scoring system, (table 2). Dorsal midtarsal wedge was performed in 5 patients (7 feet). The average age at operation was 18 years (8-23) and follow up period was 13 years (4-19). 4 patients had good results and 2 had fair result. One patient scored poor because of severe pain limiting his walking distance which was made worse because of poor result of metatarsal osteotomy in his other foot. Four patients (5 feet) had Jahss tarsometatarsal truncated wedge arthrodesis. 2 patients (3feet) gave good result and two patients achieved poor score. Two patients who had triple arthrodesis had multiple corrective surgeries prior to this salvage procedure. One patient achieved, excellent score and other reported poor result. RESULTS Surgical procedures were divided into 5 types according to the main procedure done for cavus correction; Soft tissue procedures, Metatarsal osteotomy, Dorsal midtarsal wedge osteotomy, Jahs's truncated wedge osteotomy and triple arthrodesis. (table 2). It was difficult to categorise patients into a single operative group as many patients had more than one operation for the recurrent deformity over the period of time. In cases, where more than one procedure was done , the last major operation was accounted. Patients who had only soft tissue procedures were considered in the soft tissue group. Where bony procedure was done in addition to the soft tissue, the bony procedure was accounted. The soft tissue procedures were plantar fascia release, Steindler's release, soft tissue release and elongation of Tendo-Achilles. Soft tissue correction of deformities were performed on 10 feet in 8 patients, 4 male and 4 female. The mean age at surgery was 20 years, range 12 to 33. The follow-up period ranged from 2 - 6 years, mean 4.5 years. 6 patients achieved excellent, 3 patients gave good result and 1 patient had poor result, (table 2) Dorsal metatarsal osteotomy was performed on 14 patients (20 feet) There were 7 males and 7 female patients. First metatarsal was always operated upon and the lateral metatarsals were included depending upon the severity of the deformity. A plantar fascia release or Steindler's release was always done prior to closing the wedge osteotomy. This was to allow the metatarsals to straighten up after closing t the wedge osteotomy. The average age of patients was 22 years (12- 54) and average follow-up period was 7 years DISCUSSION Pes cavus is a foot with a high arch that fails to flatten with weight bearing. It consists of equinus deformity of forefoot in relation to hindfoot and is often accompanied by clawing of toes. While a pure cavus deformity does occur, more often than not it is associated with forefoot and/or heel varus deformity. This complex foot deformity presents in varying degrees of severity. A knowledge of etiology of pes cavus is essential for successful treatment of the deformity. The pathomechanism that produce a cavus foot vary with the disease process. There is little doubt that in majority of cases the condition is caused by a muscle imbalance, however, which muscles are producing the imbalance is still controversial. The successful treatment of pes cavus has been a challenge, a concern and a problem for orthopaedic surgeons since surgery was accepted as a method of treatment. The goal of surgical treatment is to produce a plantigrade, stable foot. A review of literature on the development of treatment for this condition reveals that a large number of surgical procedures and their modification have been described for the treatment of pes cavus. There is no single surgical procedure, that could be universally applicable to the pes cavus deformity. The severity of deformity in pes cavus may vary greatly and routine use of the same procedure for all such deformities does not seem appropriate. In fact unless the surgery is tailored precisely to address the underlying Vol. 8 No. 4, October - December 2001 216 JK-PRACTITIONER pathology, it will invariably fail. The surgical procedures are generally divided into soft tissue and bony procedures. A variety of soft tissue surgical procedures, alone or in combination with bony surgery have been described. The keystone procedure is a plantar fascia release. This at times, can be extended to Steindler's release, which involve in addition, subperiosteal stripping of short muscles attached to calcaneus. Tendon transfers and or lengthening are used to correct the dynamic components of pes cavus deformity depending upon the severity and location of deforming component. Paulos et al a) in 1980 demonstrated that foot deformity in some older children could be successfully treated with soft tissue procedures alone. Roper and Tibrewal in 1989(3), reported that the deformities in pes cavus in Charcot Marie Tooth disease could be treated by soft tissue surgery alone, which could certainly postpone the necessity for triple arthrodesis and, in many cases, might obviate its need altogether. They suggested that surgery should be performed early in life and before deformity became severe, although in older patients with severe deformity, reasonably satisfactory results could be obtained. In this study, 90% of these patients achieved excellent to good result at a mean follow up period of 4.5 years. This suggests that soft tissue procedures are most useful for correction of flexible deformity especially in younger patients. There have been a variety of osseous procedures described in the treatment of pes cavus. These procedures are usually most useful for significant fixed deformity or in the case of supple deformity with unattainable muscle balance. Metatarsal osteotomy for correction of forefoot deformity in pes cavus was described by Swanson et al in 1956(4>. They presented good results in four patients where in dorsal closing wedge osteotomy was performed at proximal parts of the metatarsals using green stick technique. Fixed plantar flexed first metatarsal can be addressed with a dorsal closing wedge osteotomy of the first metatarsal. Alexander, I.J. and Johnson, K.A., 1989 <». Later in 1990 Watanabe <6) showed 84% excellent or good results in 50 operations performed on 39 patients. He described it as a technically easier and safer procedure because the osteotomy is performed in an arch area where the neurovascular bundle is protected by the intrinsic muscle mass. In this study none of the patients had osteotomy of all five metatarsals as described in the original technique. A selective approach had been adopted depending upon the involvement of individual metatarsals in the formation of cavus deformity. Since the first metatarsal is almost always involved in the forefoot plantaris deformity, all patients had at least first metatarsal osteotomy, followed if necessary the second, third or fourth metatarsals. This study shows 65% excellent to good results, 20% achieved fair result and poor result was shown by 15 % of patients. These results were far less than 84% success rate described by Watanabe." A variety of midfoot osteotomies/arthrodeses have been utilised for correction of rigid pes cavus deformity. Saunders J T (1935y described an anterior tarsal wedge resection for correction of severe rigid pes cavus deformity. He reported excellent results in 59 out of 102 patients. In half of the cases the anterior tarsal wedge resection was combined with additional soft tissue procedures. Cole WH in 1940' described a dorsal wedge osteotomy involving the midtarsal bones. The size of the wedge depend upon the amount of cavus component. He suggested this procedure only after soft tissue surgery had failed. In this study 4 feet (57%) gave good result, 2 feet (29%) achieved fair and one foot (14%) got poor result. Jahss M H in 1980,'described a new technique of midfoot arthrodesis for correction of pes cavus deformity but, expressed the need of a normal muscle balance as a prerequisite.. A dorsal truncated wedge was removed at the tarsometatarsal joints. He claimed that a truncated wedge did not shorten the overall length of the foot, but only lower the height of foot, making wearing of shoes comfortable. He reported excellent results in regard to relief of metatarsal pain, calluses and deformity in patients with mild to moderate deformity and satisfactory results in more severe cases. In this study good results were shown in 2 feet (40%), fair in one foot (20%) and poor in 2 feet (40%). It is difficult to comment on the success of this procedure because of small number of patients in this study as well as short follow up period (2-3 years). The poor results shown in this study were mainly because of failure to relieve pain and ankle instability. Most authors who have discussed operative management of pes cavus deformity include triple arthrodesis as a consideration. Triple arthrodesis and appropriate soft tissue procedures should be most useful for the treatment of severe cavovarus deformity with markedly limited subtalar motion in a skeletally mature foot. Triple arthrodesis removes the shock absorber function of the middle and hind parts of the foot. The ankle is subjected to increased stress. This is a major problem for patients who have peripheral neuropathy. The recurrence of deformity and high incidence of residual deformity along with loss of proprioception and balance makes the ankle joint vulnerable to instability and eventual osteoarthritic changes. Wetmore and Drennan10 Reported 47% long term poor results in Charcot-Marie-Tooth disease patients who had triple arthordesis. Wukich et al" demonstrated radiographic evidence of degenerative joint disease in 62% feet and 24% ankles which had triple arthrodesis for pes cavus in Charcot Marie Tooth disease. Mann and Hsu12 believe that triple arthrodesis provides a stable plantigrade foot in the face of a progressive disorder. They suggest triple arthrodesis as an index or primary bony procedure, requires few subsequent procedures to treat recurrent or residual deformity. They reported satisfactory Vol. 8 No. 4, October - December 2001 217 JK-PRACTITIONER result in 5 out of 12 patients with Charcot Marie Tooth disease whojiad triple arthrodesis for pes cavus deformity. Only two patients in this study underwent triple arthrodesis. Both had multiple surgeries prior to triple arthrodesis which was used as a salvage procedure. One showed excellent result and other gave poor outcome. Results of the surgical procedures for pes cavus deformity are difficult to evaluate and compare because of variety and combination of procedures. Lack of uniform preoperative data made it impossible to construct a retrospective picture of the preoperative condition. Moreover many patients had multiple surgeries for the correction the progressive deformity. Therefore interpretation of the results of an isolated procedure in such cases would be difficult. Soft tissue surgery had generally given better results. In most of the cases, surgery was done on a virgin foot and the deformity was flexible as well. Among the midfoot procedures metatarsal osteotomy showed better overall results. Majority of these cases had first ray predominance in cavus formation, where this procedure was best indicated for correction of the deformity. The dorsal midtarsal wedge arthrodesis and Jahss tarsometatarsal truncated wedge arthrodesis gave comparable results. These were done on rigid feet with moderate to severe deformities which in many cases was progressive. Surgical treatment of pes cavus requires meticulous planning. In early cases when the deformity is mild and foot is supple, soft tissue procedures will correct the deformity and may halt or delay the need for extensive bony surgery. Appropriate tendon transfers may be required to achieve a balanced foot. There is little doubt that with a plantar flexed first metatarsal, in some cases second or third as well, a closing wedge dorsiflexion osteotomy at the base of first metatarsal is the treatment of choice. In cases of global anterior cavus, where all the tarsometatarsal joints are hyper plantar flexed, various midfoot procedures exist, but each has inherent pitfalls. Correction can be achieved through multiple metatarsal osteotomies, Jahss tarsometatarsal truncated wedge arthrodesis or Cole's dorsal midtarsal closing wedge arthrodesis/osteotomy. Occasionally triple arthrodesis, as a salvage procedure is required. The need for hindfoot correction can be determined by Coleman's lateral block test. In patients with fixed hindfoot varus, a calcaneal osteotomy is required. References: 1. Steindler A, The treatment of pes cavus (hollow claw foot). Archives of Surgery. 1921; 2:325-337. 2. Paulos L, Coleman S S and Samuelson K M. Pes cavovarus. J Bone Joint Surg 1979; 62A(56): 942-953. 3. Roper B A, Tibrewal S B. Soft tissue surgery in Charcot-MarieTooth disease. British Medical Journal 1989; 71-B: 17-20 4. Swanson A B, Browne: H S and Coleman J D. The cavus footconcepts of production and treatment by metatarsal osteotomy. J Bone Joint Surg 1966; 48A.1019 5. Alexander I J and Johnson K A. Assessment and management of pes cavus in Charcot-Marie-Tooth disease. C lineal orthop and related research. I989;246:273-281. 6. Watanabe R S. Metatarsal osteotomy for the cavus foot Clinical Orthopaedic and related research. 1990;252:217-230. 7. Saunders J T. Aetiology and treatment of clawfoot. Report of the results in one hundred and two feet treated by anterior tarsal resection. Archives of Surgery. 1935; 30(2): 179-198. 8. Cole W H. The treatment of claw foot. J Bone Joint Surg 1940; 22: 895-908. 9. Jahss M H, Tarsometatarsal truncated-wedge arthrodesis for pes cavus and equinovarus deformity of the fore part of the foot. J Bone Joint Surg 1980; 62A:713-722 10. Wetmore R S et al. Long term results of triple arthrodesis in Charcot-Marie-Tooth disease.JBJS1989;71-A:417-422. 11. Wukich et al. Long term study of triple arthrodesis for correction of pes cavovarus in Charcot-Marie-Tooth disease. J Paediatr Orthop. 1989;9:433-437. 12. Mann D C and Hsu J D. Triple arthrodesis in the treatment of fixed cavovarus deformity in adolescent patients with CharcotMarie-Tooth disease. Foot and Ankle. 1992,13:1-6 Vol. S No. 4, October - December 2001 218