CARPAL VARUS IN EIGHT WORKING SHEEPDOGS
W McCartney MVB, CertSAO, Dipl ECVS, PhD, MRCVS and D Callanan MVB, MRCVS
Marie Louise Veterinary Hospital , 38 Warrenhouse road, Baldoyle, Dublin 13, Ireland
Objective: Describe the results of a new surgical technique
Tine scale and Design: A retrospective anaylsis of cases over a 14 year period
Relevance: The condition and surgery are unreported up to now
Previous experience or theory: None
Change to existing practice or theory: New technique and condition so no change just
additional information
Authors impact claim: 2
ABSTRACT
Eight Border Collies working in steep hilly sheep farms were treated over a fourteen year period.
All the cases presented with marked carpal varus deformity which in three cases occurred after a
stumble whilst running downhill. Plain and dynamic radiographs revealed a ruptured short ulnar
collateral ligament. The first four cases were treated with figure of eight prosthetic ligament
replacment using wire in the first two cases and nylon in the next two. Three of these four cases
had to be re-operated on again as the repair failed or did not provide sufficient support when the
dog returned to work, and one was lost to follow up. The fifth case had both nylon and wire but
as with the first four cases did not succeed in returning the dog back to work. All these cases had
significant decrease range of motion and two had to have pancarpal arthrodesis afterwards. The
last three cases were managed by harvesting the portion of the lateral digital extensor going to
fifth phalanx. The remaining portion of the lateral digital extensor to the fifth phalanx was
sutured to the portion of the lateral digital extensor going to the fourth phalanx were possible.
The harvested portion of lateral digital extensor was threaded through holes drilled in the distal
ulna and ulnar carpal bone and sutured back onto itself to form a loop of tendinous tissue. A
figure of eight prolene suture was also passed through the holes to provide extra support.All of
the three cases treated by lateral digital extensor tendon harvesting returned to work
satisfactorily, but at a reduced level than before the injury and with a degree of reduced range of
motion. None of the five cases treated by wire / nylon or pancarpal arthrodesis returned to
work.Traditional methods of repair using nylon or wire did not work, and this would be a
reflection of the extra strain on the lateral carpus. Using a part of the tendon of the lateral digital
extensor providing autologous tissue with good strength and size for the intended use was
successful. Also the harvesting procedure used for this tendon did not cause a problem.
Although this small case series represents an unusual group of patients the technique may be
better than the traditional methods even for companion animals that spend most of their time on
flat ground.
KEYWORDS: Carpus, Varus, Sheepdogs, ligaments
INTRODUCTION
Carpal ligament injuries are not uncommon and are reported in literature mainly
involving the medial aspect of the carpal joint affecting the short radial ligament (Vaughan 1985;
Early and Dee 1980; Early 1978). Treatment of carpal luxation or subluxation also involves the
medial aspect (Early 1990; Whitelock 2001). Working dogs have been associated with a high
incidence of carpal ligament problems and this would in particular refer to racing greyhounds (
Guilliard 1998;Guilliard 1997).
METHODS
Eight Border Collies working in steep hilly sheep farms were treated over a fourteen year
period. All the cases presented with marked carpal varus deformity which in three cases occurred
after a stumble whilst running downhill. Plain and dynamic radiographs (Fig 1) revealed a
ruptured short ulnar collateral ligament. Following a standard approach to the lateral carpus the
remnants of the short ulnar carpal ligament were searched for but it was not always possible to
accurately locate the remaining portions of the short ulnar collateral ligament during surgery as
the ligament is so short. The first four cases were treated with figure of eight prosthetic ligament
replacment using wire in two cases and nylon in the remaining two, passed through holes drilled
in the distal ulna and ulnar carpal bone. Drilling a hole in the ulnar carpal bone was diffficult, as
the hole had to angled to avoid the articular surface. Three of these first four cases had to be reoperated on again as the repair failed or did not provide sufficient support when the dog returned
to work, and one was lost to follow up( second nylon case). The fifth case had both nylon and
wire but as with the first four cases did not succeed in returning the dog back to work. All these
cases had significant decrease range of motion following first surgery and two had to have
pancarpal arthrodesis using a carpal arthrodesis plate ( Veterinary Instrumentation, Sheffield) to
enable them to return to some degree of activity. The last three cases were managed by
harvesting the portion of the lateral digital extensor going to fifth phalanx. The remaining portion
of the lateral digital extensor to the fifth phalanx was sutured to the portion of the lateral digital
extensor going to the fourth phalanx were possible. The harvested portion of lateral digital
extensor was threaded through holes drilled in the distal ulna and ulnar carpal bone and sutured
back onto itself to form a loop of tendinous tissue. A figure of eight prolene(Ethicon, Johnson &
Johnson)suture was also passed through the holes to provide extra support (Fig 2).
RESULTS
The eight dogs were all Border Collies working in hilly conditions with 6 of the dogs
being females. The average age of the dogs was 4 years and none of the dogs were
neutered.Those cases that had just the prosthetic repair ( wire or nylon) had a temporary relief of
their symptoms but eventually their symptoms recurred.The cases of the pancarpal arthrodesis
did return to work but only at asignificantly reduced level.
All of the three cases treated by lateral digital extensor tendon harvesting returned to work
satisfactorily, but at a reduced level than before the injury and with a degree of reduced range of
motion. None of the five cases treated by wire / nylon or pancarpal arthrodesis returned to work
at an acceptable level.
preop
Fig 1. Preoperative dynamic radiograph
12wks
Fig 2. Twelve weeks post operative dynamic radiograph
DISCUSSION
Rupture of the short ulnar collateral ligament is rare as the dog stands with a natural
valgus stance, and hence the medial collateral is the usual ligament to be ruptured. Autologous
tissue such as the tendon of the abductor pllicus longus or flexor carpi radialis can be used to
replace / repair rupture of the medial lateral collateral ligament (1). The working dogs in this
report must have had extra strain on their lateral carpus due to the hilly conditions, in particular
the action of going downhill. Traditional methods of repair using nylon or wire did not work, and
this would be a reflection of the extra strain on the lateral carpus in hilly conditions and their
innate tendency to fail eventually under cyclic loading. Using a part of the tendon of the lateral
digital extensor provides autologous tissue with good strength and size for the intended use.
Also the harvesting procedure used for this tendon did not cause a problem in itself. There is no
reliance on inorganic material to maintain joint stability
CONCLUSIONS
Use of autologous tissue from the lateral digital extensor to repair a ruptured short ulnar
ligament can successfully enable working sheepdog to return to work.
REFERENCES
Early, T.D. (1978) Canine Carpal Ligament Injuries. Veterinary Clinics of North America 8:183
Early, T.D. and Dee, J.F. (1980) Trauma to the Carpus, Tarsus and Phalanges of the Dog and
Cat. Veterinary Clinics of North America 10: 771
Early, T.D.(1990) Carpal and tarsal injuries. In Current techniques in small animal surgery.
Editor M.J. Bojrab. Lea & Febiger. Page 871
Guilliard, M.J.(1997) Dorsal radiocarpal ligament sprain causing intermittent carpal lameness in
high activity dogs. Journal of Small Animal Practice 38:10, 463-465
Guilliard, M.J. (1998) Enthesiopathy of the short radial collateral ligaments in racing
greyhounds. Journal of Small Animal Practice 39:5,227-230
Vaughan, L.C. (1985) Disorders of the carpus in the dog. British veterinary journal 141, 435-44
Whitelock, R. (2001) Conditions of the carpus in the dog. In Practice 23; 1, 12-13