New research led by RCVS Specialist in Small Animal Orthopaedics, Steve Butterworth at Weighbridge Referral Centre, Swansea has found that tibial tuberosity advancement (TTA)-Rapid 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) affects 3% to 5% of dogs1.

Past research has demonstrated satisfactory short (6-12 weeks)2 and medium (mean 16 months)3 term outcomes for lame dogs treated with TTA.

However, Steve says there is limited research on longer (>16 months) follow-up periods.

It has also been speculated that dogs with tibial plateau angles (TPA) of greater than 30⁰ are not well suited for a TTA4. 

For the study5, the researchers reviewed patient records for a total of 149 TTA-Rapid procedures carried out in 120 dogs over an 80 month period. 

They also reviewed owner questionnaires that evaluated the outcome of 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%), with a median follow-up time of 37.5 months.

This cohort included a wide range of breeds, aged between 2&12 years and with bodyweights 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 of the dogs (40.6%) had a TTA performed with a TPA less than 30◦ and 38 (59.4%) with a TPA of 30◦ or more. 

Of the 79 procedures, meniscal injury was noted in 27 (34.2%), surgery to stabilise the patella was required in 11 (13.9%), there was one surgical site infection (treated successfully with a short course of antibiotics), one dog sustained a fracture of the tibial seven days after surgery, and one sustained a late meniscal tear 12 months after initial surgery (treated successfully by partial meniscectomy).

The outcome was judged to be satisfactory, based on frequency of lameness, in 63 (98.4%), while satisfactory outcomes were achieved in 61 (95.3%) based on severity of lameness and in 50 (78.1%) based on mobility score.

Statistical analysis showed that age, bodyweight, tibial plateau angle (TPA), meniscal injury, and concurrent patellar surgery did not influence the outcome, but 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.

The study also revealed no evidence to support the suggestion that dogs with TPAs of greater than 30◦ may be inappropriate candidates for TTA - after testing several parameters to judge outcome including frequency of lameness, severity of lameness, distance walked daily and mobility score.

Steve said: “This research is important in trying to ensure that decisions on whether to use 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.”

References 

  1. Hynes J, Manfredi JM, Shull SA. Cranial cruciate ligament disease is perceived to be prevalent and is misunderstood in field trial sport. J Am Vet Med Assoc. 2023 Jul 14:1-6. doi: 10.2460/javma.23.01.0004. Epub ahead of print. PMID: 37451677.
  2. Samoy Y, Verhoeven G, Bosmans T, Van der Vekens E, de Bakker E, Verleyen P, et al. TTA Rapid: description of the technique and short term clinical trial results of the first 50 cases. Vet Surg. 2015;44:474–84.
    Butterworth SJ, Kydd DM. TTA-Rapid in the treatment of the canine cruciate deficient stifle: short- and medium-term outcome. J Small Anim Pract. 2017;58:35–41.
    Dyall B, Schmökel H. Tibial tuberosity advancement in smallbreed dogs using TTA-Rapid implants: complications and outcome. J Small Anim Pract. 2017;58:314–22.
  3. Boudrieau RJ. Tibial plateau leveling osteotomy or tibial tuberosity advancement? Vet Surg. 2009;38:1–22.
  4. Boudrieau RJ. 2007 ACVS Veterinary Symposium - the surgical summit: pre-symposium laboratories: TTA Lab. October 18–21 Chicago, Ilinois. Published ACVS Germantown, MD, 2007.
    Williams N. Cranial cruciate ligament rupture and tibial tuberosity advancement. Veterinary Times. September 14, 2009. https://www.vettimes.co.uk/app/uploads/wp-post-topdf-enhanced-cache/1/cranial-cruciate-ligament-ruptureand-tibial-tuberosity-advancement.pdf.
  5. Butterworth SJ, Schofield I. TTA-Rapid for treating the canine cruciate deficient stifle: Medium to long-term outcome and analysis of risk factors. Vet Rec. 2024;e3795. https://doi.org/10.1002/vetr.3795 

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