Ex vivo evaluation of the effect of various surgical procedures on blood delivery to the patellar tendon of dogs

Radiographic evaluation of patellar tendon length following corrective surgical procedures for medial patellar luxation in dogs

Objective

To quantify changes in the patellar tendon length following surgical correction of medial patellar luxation in dogs and evaluate potential risk factors associated with patellar tendon elongation.

Study design

Retrospective case series (n = 50).

Methods

Dogs that underwent surgery for medial patellar luxation correction and had 2–3 months follow up were included. Digital radiographs were utilized to quantify the patellar tendon length to patellar length ratio at various follow-up points. Odds ratio comparisons between potential risk factors associated with changes in patellar tendon length were performed.

Results

Post-operative patellar tendon lengthening of ≥ 5% was observed in 20% of stifles and post-operative patellar tendon shortening of ≥ 5% was observed in 22% of stifles at the 2–3 month follow up period. The risk factors including age, body weight, trochleoplasty and grade of medial patellar luxation were not significantly associated with risk of patellar tendon elongation. Patellar tendon lengthening was not associated with recurrence of luxation.

Conclusion

Patellar tendon lengthening and shortening can be observed in dogs following common medial patellar luxation corrective procedures in the short term follow up period. Patellar tendon lengthening does not appear to be associated with age, weight, trochleoplasty, grade of luxation, or risk of luxation recurrence.

Patella tendinopathy Zoobiquity - What can we learn from dogs?

BACKGROUND

Patella tendinopathy is an overuse condition. Pathogenesis and identification of intrinsic risk factors have largely eluded the orthopaedic world. The cranial cruciate ligament (CrCL) in dogs is the equivalent to the human anterior cruciate ligament (ACL). We report the effect of two canine proximal tibial osteotomy procedures in the veterinary literature on patella tendon moment arm and describe the biomechanical rationale for a tibial tubercle osteotomy for treatment of patella tendinopathy in the human.

METHODS

A literature review of studies reporting clinical complications of TTA and TPLO to form an observational animal cohort study in dogs.

RESULTS

The veterinary literature reports an overall clinical complication rate of up to 61% for TTA and up to 50% for TPLO respectively. Complications associated with the extensor mechanism of the knee are <1% for TTA compared to 1.9-19% for TPLO. Radiographic thickening of the patella tendon and tendinopathy is seen in one to 80% of TPLO cases. The TPLO decreases the moment arm of the extensor mechanism meaning increased force is required in the patella tendon to achieve the same torque when compared to the TTA which increases the efficiency of the extensor mechanism. This difference may account, in part, for the post-operative complications reported to the patella and patella tendon following TPLO.

CONCLUSION

This observational animal cohort study demonstrates a biomechanical rationale for investigating diagnostic and potential treatment options, including a tibial tubercle osteotomy, for patella tendinopathy in humans based on this principle.

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.