Correction of congenital deformity of hind limbs of cat by femoro

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					Case Report                                                       Veterinarni Medicina, 53, 2008 (8): 452–455

Correction of congenital deformity of hind limbs of cat
by femoro-tarsal arthrodesis: a case report
J. Park1, K.R. Cho1, B.C. Sutradhar¹, D. Chang2, S.H. Choi1, G. Kim1
    Laboratory of Veterinary Surgery, 2 Laboratory of Veterinary Radiology, College of Veterinary
    Medicine, Chungbuk National University, South Korea

ABSTRACT: Congenitally deformed tibia-fibulas of both hind limbs were diagnosed in a four-month-old, female,
domestic shorthair cat that was unable to bear weight and whose movement was painful on both stifle and hock
joints. Bleeding was observed repeatedly from the wound made by deformed tibias at the cranial sides of hock
joints where the bones were exposed. Radiography and computed tomography revealed a corn-shaped tibia and
bow shaped fibula which extended cranio-distally without formation of the hock joints. Femoro-tarsal arthrodesis
was successfully executed on both hind legs after exclusion of the deformed and pliable tibia-fibulas. Follow-up
radiography showed that bone fusions had gradually improved and were without complications. Postoperatively,
the cat was capable of walking on the corrected hind legs and running on the movement of hip joints. To the
authors’ knowledge, this is the 1st reported case of femoro-tarsal arthrodesis in a cat. In this case, femoro-tarsal
arthrodesis resulted in a satisfactory outcome for congenitally deformed tibia-fibulas in cat.

Keywords: femoro-tarsal arthrodesis; lame; shorthair cat

  Arthrodesis (fusion) of a joint is an orthopedic         femoral and tarsal arthrodesis separately in cats;
salvage procedure most often performed in the              however, no instances of femoro-tarsal arthrodesis
carpus and tarsus (Denny and Butterworth, 2000).           have been reported. In this case, there was no treat-
The common reasons for arthrodesis in veterinary           ment option other than arthrodesis and the authors
surgery are hyperextension injuries, luxation, de-         chose this femoro-tarsal arthrodesis technique for
generative conditions of the palmar or carpal liga-        the correction of the deformity after excluding the
ments, immune-mediated arthritis, non-repairable           pliable, congenitally deformed tibia-fibulas from
communicated intra-articular fractures, severe             the affected limbs. This case report should prove
degenerative joint disease, severe soft tissue or          instructive for the future treatment of feline pa-
bone trauma, refractory infection, radial paralysis        tients with this condition.
and ischiatic nerve injury (Trostel and Radasch,
1998; Harasen, 2002; Kirsch et al., 2005). Plate
stabilization of any arthrodesis provides the most         Case history
substantial and reliable fixation (Harasen, 2002).
Different sizes of bone plates are used for arthro-          A four-month-old female domestic short-hair cat
desis in different positions, although the dorsal          was referred to the veterinary medical center with
bone approach is the most commonly used tech-              congenitally deformed tibia-fibula of both hind
nique in small animals (Guerrero and Montavon,             limbs. Its prior history was unknown as it was an
2005). Cats and dogs are able to walk and engage           orphan but the deformity of both hind legs was
in non-athletic activity with the loss of tarsal or        observed. The cat exhibited non-weight bearing
stifle motion. In the literature, many surgical tech-      lameness in both hind limbs and was in severe pain
niques have been described for surgery to achieve          during palpation of the stifle and hock joints for

Veterinarni Medicina, 53, 2008 (8): 452–455                                                      Case Report

                                                                      Figure 1. The deformed tibia-fibulas
                                                                      are exposed cranio-distally through the
                                                                      slitting of skin (A); bleeding is not
                                                                      observed postoperatively (B)

physical examination. Its movement was greatly         Daewon®, Daewon Pharmacy, Korea), 3 mg/kg tra-
restricted at hock joints where the deformed tibia-    madol hydrochloride, i.v. (Tamadol®, Dongkwang
fibulas were exposed cranio-distally through the       Pharmacy, Korea) and 50 mg/kg ampicillin/sul-
slitting of skin (Figure 1A). The deformed legs were   bactam, i.v. (Ubacillin®, Whanin Pharmacy, Korea).
always kept straight and the movement of joints was    General anesthesia was induced with 5 mg/kg pro-
difficult. Preoperatively, a standard ventro-dorsal    pofol, i.v. (Pofol®, Jeil Pharmacy, Korea), followed
radiograph (Figure 2A) and computed tomography         by 2–2.5% isoflurane (Aerane®, Ilsung Pharmacy,
(Figure 3) were generated in order to locate the       Korea) in oxygen administered through an endotra-
instability and evaluate any other abnormalities in    cheal tube.
the joints. Both images confirmed the deformity          Two separate surgeries were performed on this
of both the tibia and fibula on the hind legs. The     cat. In the first the left hind limb was corrected;
true joints were absent in the deformed stifle and     in the second four months later, the right was cor-
tarsal joints.                                         rected. The skin was incised over the craniolateral
  The results of laboratory tests were noteworthy      aspect of the stifle, extending from the mid-diaph-
only for the high creatine phosphokinase level ob-     ysis of the femur to the middle of the metatarsal
served (878 IU/l; reference range, 56 to 529 IU/l).    bone. The cranial tibial muscle was elevated to
The cat was premedicated with 0.05 mg/kg acepro-       expose the proximal tibia. Then the cranial tibial
mazine, s.c. (Sedaject®, Samwoo Pharmacy, Korea),      and long digital extensor tendons were retracted
0.05 mg/kg atropine sulfate, s.c. (Atropine Sulfate    and elevated to expose the distal tibia, although

                                                                      Figure 2. Ventro-dorsal views of radio-
                                                                      graphs; before (A) and one year after
                                                                      surgery of right hind limb (B). Con-
                                                                      genitally deformed bones are excluded
                                                                      and corrected by femoro-tarsal arthro-
                                                                      desis. Left hind limb was corrected first
                                                                      and then right hind limb four months

Case Report                                                     Veterinarni Medicina, 53, 2008 (8): 452–455

                                                                         Figure 3. Cranial view (A) and caudal
                                                                         view (B) of 3-dimensional computed
                                                                         tomographies of left hind leg in cat.
                                                                         Notice congenitally deformed stifle and
                                                                         tarsal joints where the true joints are

all muscles were short and atrophied in this area.        after surgery (Figure 1B and 2B) indicated that there
Finally both the tibia and fibula were separated          was no unexpected change in the cat’s condition.
from their joints and excluded from the leg. The
articular surfaces of the distal end of femur, and
talocrural, intertarsal and tarsometatarsal joint car-    DISCUSSION
tilages were removed, using a high-speed burr fol-
lowing the contours of the bone ends to expose the          Congenital defects in cat are less common than
underlying cancellous bone. The surface was rasped        in other domestic animals and may be heritable or
and contoured until secure apportion was achieved         follow an inheritance pattern, although no indi-
at an angle of approximately 140°. Subsequently,          vidual breed of cat is significantly predisposed to
the bone plate was placed on the cranial surface of       congenital diseases (Hoskins, 1995). A congenital
the femur and talus. The wound was lavaged with           defect of the tibia-fibula is an unusual condition
warm saline solution and cancellous bone which            in a cat, although fracture of the tibia has some-
had been obtained from the tibia, was placed at           times been reported (Ozsoy, 2004). Occasionally,
the margin of the arthrodesis site. Closure of the        cat lameness includes fracture and luxation and
subcutaneous tissue and skin were carried out in          in some cases is a result of congenital knee cap
routine manner. A bivalve plastic cast was fitted         luxation (Loughin et al., 2006). Congenital and de-
for eight weeks until early radiographic evidence         velopmental problems of bones are the important
of bone bridging was observed. After the operation        causes of osteoarthritis in cat which is character-
was completed, the cat was administred 50 mg/kg           ized by degeneration of the articular cartilage, hy-
ampicillin/sulbactam, i.v. and 3 mg/kg tramadol           pertrophy of the bone at the articular margin and
hydrochloride, i.v. for seven days postoperatively.       changes in the synovial membranes (Sarah, 2007).
Radiographs were then repeated on a monthly ba-           This cat had the same degenerative changes in the
sis until good radiographic arthrodesis had been          articular margins of both stifle and hock joints. The
achieved. At four months after surgery, the result        tibial bones were deformed and fragile similarly to
of the operation was deemed to be satisfactory and        cartilage. Normally in a simple bone fracture, it is
the implants were removed. The other deformed             easy to correct the deformity by using different sur-
hind leg was then corrected using the same ap-            gical techniques because of the normal size, shape
proach. The cat had begun to use the affected limbs       of bone and joints. But in this case the stifle joints
approximately three to four weeks after the first         were partially defected and the hock joints were not
surgery, the owner noticing a consistent gradual          formed congenitally. Therefore, it was impossible
improvement. Radiography performed four and six           to correct this deformity in its normal position and
months after both surgeries revealed a complete           shape. For this reason the authors chose arthrodesis
union of the arthrodesis site.                            of the femur and tarsal bones with elimination of
   The cat walked and ran with slight lameness due to     the deformed tibia and fibula. The lengths of the
the absence of stifle joints but bleeding and pain were   tibia fibula were very short and the muscles were
not observed. The owner was completely satisfied          also abnormal in length and position. The location
with this clinical result. The evaluation at 12 months    of the patella was above the normal position of the

Veterinarni Medicina, 53, 2008 (8): 452–455                                                            Case Report

stifle joint and the hock joint was not formed. The      Dorea Neto F.A., Padilha Filho J.G., Santos L.A., Oria
positions of tibias were just beneath the skin where       A.P., Canola J.C., Stefanes S.A., Regonato E. (2007):
it pushed cranially and was finally exposed cranio-        The use of hydroxyapatite for arthrodesis in dogs and
distally without formation of hock joints.                 cats: a clinical study. Arquivo Brasileiro de Medicina
   Arthrodesis has been well documented as a treat-        Veterinaria e Zootecnia, 59, 932–938.
ment option for fractures, irreparable injuries to       Guerrero T.G., Montavon P.M. (2005): Medial plating
the articular ligaments, chronic pain and for se-          for carpal panarthrodesis. Veterinary Surgery, 34,
vere degenerative joint diseases (Moak et al., 2000;       153–158.
Dorea Neto et al., 2007). Instability induces pain       Harasen G. (2002): Arthrodesis – Part I: The carpus.
due to abnormal movement and the tension placed            The Canadian Veterinary Journal, 43, 641–643.
on the soft tissues and nerves of the joint. Thus,       Hoskins J. (1995): Congenital defects of cats. Compen-
arthrodesis relieves pain by providing a rigid sup-        dium on Continuing Education for the Practicing Vet-
port (Lesser, 2003).                                       erinarian, 17, 385–405.
   In this case, the authors chose arthrodesis to cor-   Kirsch J.A., Dejardin L.M., DeCamp C.E., Meyer E.G.,
rect this congenital defect by using bone plates for       Haut R.C. (2005): In vitro mechanical evaluation on
stabilization, which are the most substantial and          the use of an intramedullary pin-plate combination
reliable in fixation. Arthrodesis of the stifle is not     for pantarsal arthrodesis in dogs. American Journal
commonly performed except at the end stage of              of Veterinary Research, 66, 125–131.
joint disease or instability. Tarsal arthrodesis is      Lesser A.S. (2003): Arthrodesis. In: Slatter D. (ed.): Text-
suitable for the treatment of severe degenerative          book of Small Animal Surgery. 3 rd ed. WB Saunders
joint disease and is a retrieval procedure intended        Co., Philadelphia. 2170–2180.
to eliminate pain and preserve some degree of limb       Loughin C.A., Kerwin S.C., Hosgood G., Ringwood P.B.,
usage (Marie-Claude and Noel, 2007). However,              Williams J., Stefanacci J.D., McCathy R.J. (2006): Clin-
reports of femoro-tarsal arthrodesis for cats as well      ical signs and results of treatment in cats with patellar
as for other animals are rare in the literature. The       luxation: 42 cases (1992–2002). Journal of the American
arthrodesis was evaluated by radiographs imme-             Veterinary Medical Association, 228, 1370–1375.
diately after surgery and on a monthly basis. Bone       Marie-Claude T., Noel M.M.M. (2007): The use of vet-
fusion was observed after one month in this case           erinary cuttable plates for carpal and tarsal arthrod-
since the animal was of young age.                         esis in small dogs and cats. The Canadian Veterinary
   Our study is limited by the fact that this was an       Journal, 48, 165–168.
exceptional case for a cat and therefore there was       Moak P.C., Lewis D.D., Roe S.C. (2000): Arthrodesis
no scope to compare with others. The results of this      of the elbow in three cats. Veterinary and Compara-
study suggest that arthrodesis of the femoro-tarsal        tive Orthopedics and Traumatology, 13, 149–153.
joints may be a suitable and satisfactory procedure      Ozsoy S. (2004): Fixation of femur, humerus and tibia
for the congenitally deformed tibia-fibula in a cat,       fractures in cats using intramedullary threaded stein-
although more cases are needed to further define           mann pins. Veterinary Record, 155, 152–155.
complications, more suitable angles, and long term       Sarah C. (2007): Feline arthrodesis. Veterinary Focus, 3,
results.                                                   11–12.
                                                         Trostel C.T., Radasch R.M. (1998): Tarsocrural arthro-
                                                           desis: A clinical report using a circular external fixator.
REFERENCES                                                 Veterinary and Comparative Orthopaedics and Trau-
                                                           matology, 11, 193–196.
Denny E.R., Butterworth S.J. (2000): A Guide to Canine
 and Feline Orthopedic Surgery. 4th ed. Blackwell Sci-                                       Received: 2008–07–21
 ence, London. 415–419.                                                     Accepted after corrections: 2008–08–12

Corresponding Author:
Gonhyung Kim, DVM, PhD, Chungbuk National University, South Korea, College of Veterinary Medicine, Laboratory
of Veterinary Surgery, 12 Gaeshin-dong, Heungduk-gu, Cheongju 361-763, South Korea
Tel. +82 43 261 3171, fax: +82 43 261 3224, e-mail:


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