Patellar ligament rupture in the dog: repair methods and patient outcomes in 43 cases

Abstract

The medical records of dogs receiving surgery for unilateral patellar ligament rupture between 1999 and 2012 at 12 multidisciplinary referral centres were reviewed. Forty-three cases were identified; 26 were traumatic in origin; almost one-third were iatrogenic, of which over three-quarters occurred as a complication following surgical stabilisation of patellar luxation. Treatment involved primary reapposition of the ligament (36 cases). The repair was protected by circumpatellar and/or transpatellar loop(s) of orthopaedic wire, nylon, polypropylene or polydioxanone suture (34 cases). Wire loops were more likely to require surgical removal compared with loops of other materials (P=0.0014). The stifle joint was immobilised postoperatively by the applications of a transarticular external skeletal fixator (taESF) in 17 cases and by external coaptation (EC) in 8 cases; in 18 cases, no postoperative joint immobilisation was provided. Complications specific to the method of immobilisation occurred in seven of the cases with taESF and six of the cases with EC. Revision surgery to address failure of repair was required in five cases. Outcome was classified as acceptable or good in over three-quarters of the cases (31/40) and poor in less than a quarter (9/40). These data highlight patellar ligament rupture as a complication of surgical stabilisation of patellar luxation.

Surgical repair of a proximal patellar tendon avulsion in a dog utilizing triple patellar bone tunnels and modified tendon repair technique

“…Patellar tendon rupture is an uncommon injury in dogs (Shipov et al, 2008;Das et al, 2014). The patellar tendon is the terminal insertion of the quadriceps mechanism and contributes to stifle extension (Hermanson, 2012).…”

Treating canine patellar ligament rupture

“…The study by Das and others (2014) reveals a relatively high rate of second surgeries following RPL repair. Failure of repair, necessitating revision, occurred in five cases, failed wires were removed in five cases and femoral fracture occurred in a single case as a complication of TA-ESF.…”

“…Surprisingly, a number of cases (seven of 43) assessed by Das and others (2014) were managed with no tenorrhaphy and only one of these had a poor outcome. Suturing tendons may cause adhesions, resulting in increased friction and reduced function; however, this concern was reported with intrasynovial tendons in the human hand (Amadio 2005) and there is no evidence that adhesions result in poor function in the canine patellar ligament.…”

“…However, this was performed in 13 of the 43 repairs reported by Das and others (2014). Two repairs involving FLA failed.…”

“…Similarly, perhaps stifle immobilisation does little to protect an RPL repair from tensile strain. Nonetheless, the study by Das and others (2014) suggested that stifle immobilisation reduced the failure rate. Predictably, TA-ESF and external coaptation resulted in complications of their own, including femoral fracture in one case.…”