Influence of methods of joint inspection during tibial plateau leveling osteotomy on the radiographic appearance of the patellar tendon

OBJECTIVE: To determine the influence of methods of joint inspection during tibial plateau leveling osteotomy (TPLO) on radiographic appearance of the patellar tendon. STUDY DESIGN: Retrospective study. ANIMALS: Client-owned dogs (191) treated with TPLO (199). METHODS: Data collected from medical records included signalment, weight, duration of anesthesia and surgery, preoperative and postoperative tibial plateau angle (TPA), cranial cruciate ligament status, meniscal status, and meniscal treatment. Method of joint inspection was recorded as (1) arthroscopy (AR), (2) craniomedial parapatellar arthrotomy (CrMA), or (3) caudomedial arthrotomy (CdMA). The radiographic thickness of the patellar tendon (PTT) was measured preoperatively and at 8-12 weeks postoperatively. Radiographic signs of patellar tendonitis were graded as 0-2 on the basis of the severity of changes. RESULTS: Thirty-nine dogs (41 stifles) underwent AR, 86 dogs (87 stifles) underwent CrMA, and 70 dogs (71 stifles) underwent CdMA. Durations of surgery (P < .001) and anesthesia (P < .001) were longer when joints were inspected by AR than by arthrotomies. PTT was greater after AR than after CrMA (P = .004) and CdMA (P < .001). The proportion of dogs with grade 1 or grade 2 PTT was greater after AR (78.04%) than after CrMA (52.87%, P = .0065) and CdMA (28.17%, P < .001). CONCLUSION: The PTT was thicker 8-12 weeks after TPLO when stifles were inspected arthroscopically rather than via arthrotomies. CLINICAL SIGNIFICANCE: The method of stifle exploration during TPLO influences the postoperative radiographic appearance of the patellar tendon and may contribute to patellar tendinopathy.