Use of Wallace Distractor in Canine Stifle Arthroscopy

Objectives: To assess the value of the intra-articular Wallace distractor in stifle arthroscopy in the dog. Methods-Ex-vivo study: ten cadaver limbs of dogs were used to explore the stifle joints by arthroscopy each once without and once with the aid of a Wallace distractor. Radiographs and observational data were used to assess the degree of joint distraction and to evaluate any collateral intra-articular damages. In vivo study: distractor-assisted arthroscopy was thereafter performed in 12 consecutive clinical cases of dogs with cranial cruciate ligament rupture. The use of the Wallace distractor, clinical setting, time to complete joint evaluation were recorded. Results: In the cadaver study, radiographic findings showed a significant increase of the joint space after the insertion of the distractor. Visual range during arthroscopy employing the Wallace distractor increased substantially and facilitated the assessment of all visible intra-articular structures. Mean time to evaluate the femoropatellar space was 4,1 minutes, to observe cruciate ligaments 6,5 minutes and to complete joint inspection 10,1 minutes. In the clinical study, the use of Wallace distractor allowed improved arthroscopic observation of all relevant structures, without sub-patellar fat pad removal. Mean time to complete joint inspection was 28,5 minutes. Clinical significance: The use of the Wallace joint distractor may be helpful in the arthroscopic assessment of the canine stifle. It is easy to insert, it allows a considerable distraction of the joint making it easier visibility and reducing the possible need to remove the sub patellar fat pad. With its blunt pins Wallace joint distractor limits the risk of iatrogenic damage and can be easy to use even for surgeons who do not have much experience in knee arthroscopy.