The natural history of canine occult Grade II medial patellar luxation: an observational study

Abstract

Objectives To determine the risk of lameness and the rate of subsequent medial patellar luxation surgery in dogs that present with occult Grade II medial patellar luxation. Materials and methods Retrospective owner survey and review of clinical records of adult dogs diagnosed with Grade II medial patellar luxation that were initially asymptomatic and managed non‐surgically that had a minimum of 4‐year follow‐up. Clinical notes and owner questionnaires identified dogs that subsequently developed lameness and required surgery on the previously asymptomatic stifle. Results Thirty‐eight dogs were included with an average follow‐up of 51 months. Seventeen dogs re‐presented for unscheduled contralateral medial patellar luxation surgery at an average of 15 months after initial presentation. A further two dogs had chronic contralateral limb lameness after an average of 33 months after initial surgery and may have been potential surgical candidates. Clinical Significance Fifty percent of adult dogs presenting with occult Grade II medial patellar luxation subsequently developed chronic lameness or required surgery.

Outcomes and complications of a modified tibial tuberosity transposition technique in the treatment of medial patellar luxation in dogs

“…Three hundred and seventeen records were reviewed. Eighty two records were excluded due to concurrent CCL tear (42), no m-TTT performed (17), lack of follow up or incomplete records (9), angular limb deformities requiring distal femoral ostectomy (4), or wrong species (10) Body weight ranged from 1.3 kg to 72.3 kg, with a mean of 14.3 kg. Weight categories 4 included 116 small, 52 medium, 56 large, and 11 giant breeds.…”

“…Stabilizing the patella reduces pain and lameness, thereby minimizing the worsening of skeletal deformities and osteoarthritis (OA). 2,6,[8][9][10][11] Surgical treatment may require an appropriate combination of techniques to realign the extensor mechanism. 2,10,11 These techniques may include parapatellar soft tissue desmotomy or imbrication, sulcoplasty, antirotational suture, tibial tuberosity transposition (TTT), and femoral corrective ostectomy.…”

“…Surgery is indicated for grade 3 and 4 luxations, and for lower grade luxations only when it is confirmed to cause frequent or persistent lameness and pain. Stabilizing the patella reduces pain and lameness, thereby minimizing the worsening of skeletal deformities and osteoarthritis (OA) 2,6,8–11 . Surgical treatment may require an appropriate combination of techniques to realign the extensor mechanism 2,10,11 .…”

Canine medial patellar luxation

“…A recent study evaluating canine occult grade II MPL showed that the number needed to treat was two (Hamilton et al . 2020). This means that, after a minimum of 4‐year follow‐up, if surgery had been performed in all cases with occult MPL, for every dog in which surgery would have prevented an adverse outcome, another dog would have received an unnecessary surgical procedure.…”

Preoperative and postoperative stance analysis in dogs with patellar luxation confirms lameness improvement after surgery

“…It has been reported that for every occult grade 2 medially luxating patella that was presented to a clinic and surgically corrected, 1 dog would have had an unnecessary surgery to prevent lameness within 4 years. 6 Reported postoperative complication rates vary between 13% and 48%. 7 A common complication is reluxation, which has been reported in 8% and 48% of operated dogs and is more likely to occur in large breed dogs.…”