Case summary A 2-year-old female spayed domestic shorthair cat presented with acute left pelvic limb lameness after suspected trauma. Orthopaedic and radiographic findings were consistent with rupture of the medial collateral and caudal cruciate ligaments. Surgical exploration identified complete rupture of the caudal cruciate and medial collateral ligaments, as well as a crushed medial meniscus, necessitating partial medial meniscectomy. Primary repair of the medial collateral ligament was performed and a Mini TightRope (Arthrex) prosthesis was positioned to concurrently aid stifle stability following the rupture of the two ligaments. At 8 weeks postoperatively, the cat demonstrated normal gait and pain-free stifle manipulation, with radiographs confirming implant stability and no complications. No lameness was reported by the owner 2 years postoperatively.
Relevance and novel information This is the first case report of the use of bone tunnels and a Mini TightRope implant to address complete medial collateral and caudal cruciate ligament rupture and stabilise the stifle in a cat. This novel technique allowed for stabilisation without the need for external coaptation, enabling an early return to function.
Keywords: Caudal cruciate ligament; Mini TightRope; extracapsular suture; medial collateral ligament; stifle ligament.
Plain language summary
Repairing two torn knee ligaments in a cat with a single implant A 2-year-old cat suddenly became lame on one back leg after an injury. Examination and radiographs showed that two important knee (stifle) ligaments – the medial collateral ligament and the caudal cruciate ligament – were torn. During surgery, both ligaments were confirmed to be completely ruptured, and part of the medial meniscus (a cushioning cartilage) was also found to be damaged and was removed. The torn medial collateral ligament was repaired, and the knee was stabilised using a Mini TightRope (Arthrex) implant placed through small bone tunnels. This single implant provided support for both injured ligaments. The cat walked normally and was pain free 8 weeks after surgery. Radiographs showed the implant was stable and there were no complications. Two years later, the cat remained sound with no lameness. This is the first reported case of using a Mini TightRope in a cat to stabilise both of these ligaments at once. The technique provided strong internal stabilisation, avoided the need for an external brace or cast and allowed the cat to regain normal function quickly.
