Accuracy and safety of stifle arthrocentesis and injection based on two established and two new landmarks: Ex vivo study in dogs

Objective To determine the accuracy and safety of two established landmark‐based techniques and two novel techniques for stifle arthrocentesis in dogs. Study design Ex vivo prospective study. Animals A total of 32 paired canine cadaver pelvic limbs. Methods An electronic survey assessed technique prevalence among surgeons. Pelvic limbs ( n = 32) were randomized to one of four techniques; lateral intercondylar notch (LINC), infrapatellar (INFRA), suprapatellar (SUPRA), or proximal lateral parapatellar pouch (POUCH) technique, with n = 8 per group. Repositions, attempts, and synovial fluid presence were recorded. Stifle arthrography assessed accuracy. India ink assay assessed iatrogenic articular cartilage injury (IACI). Omnibus tests were used ( p < .05), with post hoc Bonferroni‐correction ( p < .0083). Results A total of 40 surgeons responded, with LINC most commonly used (35/40, 87.5%). All tested techniques were accurate (8/8, 100%, p > .9). INFRA and SUPRA required more needle repositions (median 3 and 2, respectively) than LINC and POUCH (median 1 for both), ( p = .001). LINC and SUPRA produced no IACI, INFRA (6/8, 75%) and POUCH (3/8, 37.5%) ( p = .007). Over half of IACI produced with INFRA exceeded 10 mm 2 in area, all on weightbearing cartilage ( p = .041). POUCH injuries occurred exclusively on non‐weightbearing cartilage ( p = .041). Conclusion LINC and INFRA are currently used clinically and were accurate; however, INFRA required increased repositions and had high IACI rates on weightbearing cartilage. Two novel techniques were feasible and accurate; SUPRA was safe with no IACI, while POUCH had high IACI risk on non‐weightbearing cartilage. Clinical significance SUPRA may be a safer alternative than current established techniques and warrants further clinical investigation. INFRA carries high IACI rates.