New research by orthopaedic specialist Steve Butterworth at CVS’ Weighbridge Referral Centre has found that tibial tuberosity advancement (TTA)-Rapid, a popular technique to treat cruciate ligament rupture in dogs, offers a good medium to long-term treatment outcome for canine cranial cruciate ligament failure – even in patients with tibial plateau angles of greater than 30⁰.
Cranial cruciate ligament insufficiency (CCLI) is one of the most prevalent orthopaedic problems in canines, affecting 3 to 5 percent of dogs (Hynes et al., 2023). It is a degenerative condition that is a common cause of pelvic limb lameness, resulting in stifle instability, mobility dysfunction and pain.
TTA is a popular surgical procedure to treat dogs showing lameness associated with CCLI. Though past research has highlighted satisfactory short (6-12 weeks) (Samoy et al., 2015) and medium (mean 16 months) (Boudrieau et al., 2009) term outcomes, there is limited research on longer (>16 months) follow-up periods. It has also been speculated that dogs with tibial plateau angles (TPA) greater than 30⁰ are unsuitable for a TTA (Boudrieau et al., 2007).
The researchers reviewed patient records for 149 TTA-Rapid procedures in 120 dogs over an 80-month period. They also reviewed owner questionnaires that evaluated the outcome at least six months after surgery, using a validated clinical metrology instrument, Liverpool Osteoarthritis in Dogs (LOAD). Follow-up questionnaires were received from owners of 64 of the 120 dogs (53.3 percent), with a median follow-up time of 37.5 months. This cohort included a wide range of breeds, aged between 2 and 12 years and with body weights ranging from 6.3 to 41.8kg. The dogs included 37 females and 27 males, and of the 79 limbs treated in these dogs, 41 were left, and 38 were right. The researchers found 26 dogs (40.6 percent) had a TTA performed with a TPA less than 30◦ and 38 (59.4 percent) with a TPA of 30◦ or more. Of the 79 procedures, meniscal injury was noted in 27 (34.2 percent), and surgery to stabilise the patella was required in 11 (13.9 percent). In addition, there were surgical site infection (treated successfully with a short course of antibiotics) in one dog, a fracture of the tibial seven days after surgery in one dog and a late meniscal tear 12 months after initial surgery (treated successfully by partial meniscectomy) in one dog.
The outcome was judged to be satisfactory in 63 (98.4 percent) based on the frequency of lameness, while satisfactory outcomes were achieved in 61 (95.3 percent) based on the severity of lameness and in 50 (78.1 percent) based on mobility score. Statistical analysis showed that age, body weight, TPA, meniscal injury and concurrent patellar surgery did not influence the outcome, but the time to follow-up positively correlated with mobility score, suggesting mobility declined with time from surgery.
The researchers concluded that the long-term (median of 37.5 months) outcome for dogs undergoing TTA-Rapid for cranial cruciate ligament disease is satisfactory, with no risk factors associated with poorer outcomes identified. Their study also revealed no evidence to support the suggestion that dogs with TPA greater than 30◦ may be inappropriate candidates for TTA – after testing several parameters to judge outcome, including the frequency of lameness, severity of lameness, distance walked daily and mobility score.
Butterworth said: “This research is important in ensuring that decisions on using this treatment modality are based on sound clinical evidence. The only factor identified that influenced the outcome measure was that of time since surgery. All other factors, including TPA, had no effect on the outcome.”
The TTA-Rapid for treating the canine cruciate deficient stifle: Medium to long-term outcome and analysis of risk factors paper has been now published in Vet Record.
