New tool and surgery for mild knee cap slipping in dogs

Abstract

OBJECTIVE: To describe a novel tool and stabilization technique for tibial tuberosity transposition (TTT) in dogs with medial patella luxation (MPL) and to report short-term results. METHODS: This retrospective case series included client-owned dogs diagnosed with grade I or II MPL treated at a private orthopedic practice between January 2015 and June 2020 using a novel tibial tuberosity transposition tool and technique (TTTT). The TTTT involves a frontal plane incomplete osteotomy of the tibial crest, tool fixation, and controlled crest bending. Following TTT, the tibial tuberosity is stabilized with a spacer pin between the transposed tuberosity and the inner surface of the medial tibial cortex. Dogs were excluded if femoral deformities were present or if bone reconstruction procedures other than TTTT, trochleoplasty, or patellar groove replacement were performed. Clinical outcomes were assessed at a 2-month follow-up. RESULTS: 29 dogs (42 stifles) underwent unilateral, staged bilateral, or single-session bilateral TTTT procedures. Dogs were of various breeds, aged 2.7 years and weighing 7.7 kg. In 3 tibias, adjunctive fixation was used due to concerns for distal crest integrity, while 39 tibias were stabilized with 1 spacer pin. All osteotomies reached union without complications and 41 of 42 (98%) stifles showed good to excellent outcomes at 2 months. One dog experienced MPL recurrence, successfully treated with a trochleoplasty. CONCLUSIONS: The TTTT is appropriate for TTT in the management of dogs with grade I and II MPL. CLINICAL RELEVANCE: This study highlights the potential effectiveness of the TTTT as an appropriate surgical management approach for dogs with grade I and II MPL.