Mid- to long-term outcomes after centre of rotation of angulation-based levelling osteotomy in dogs with cranial cruciate ligament rupture

Objectives
Centre of rotation and angulation-based levelling osteotomy (CBLO) is a treatment option for dogs with cranial cruciate ligament rupture, but only limited outcome data are available for this procedure. This retrospective case-series presents mid- and long-term outcomes after CBLO.

Material
Medical records for CBLO-operated dogs over 15 kg were screened for surgery date, meniscal pathology, pre- and post-surgical tibial plateau angles (TPA) and post-surgical complications. Patients were invited for follow-up examinations, and owner satisfaction was assessed using a questionnaire. Lameness was evaluated subjectively using the Liverpool Osteoarthritis in Dogs (LOAD) questionnaire and using a pressure sensitive walkway system. Radiographs were graded for osteoarthritis.

Results
Ten dogs (12 joints) were included. Five joints were treated for meniscal injuries. Surgery reduced the mean [range] TPA from 30° [22-34] to 9° [4-11].
Major complications were observed in 4/11 dogs (fibula fracture (4/4), implant failure (2/4) and/or surgical site infection (2/4)). Follow-up was performed 134-669 (mean 474) days after surgery. Long-term owner satisfaction was high with LOAD scores 7-18 indicating mild (5/11) to moderate (6/11) articular disorders. No clinical lameness was detected in 7/10 dogs. Peak vertical force and vertical impulse in operated (mean 35.8/9.9, range 27.8-49.4/5.7-13.3) and contralateral pelvic limbs (mean 34.1/9.5, range 31.6-34.2/6.2-11.5) were not statistically different (P>0.05). Osteoarthritis progression was observed in 7/12 joints.

Impact/ Clinical significance
CBLO in dogs offers good mid- to long-term outcomes regardless of post-surgical complications and osteoarthritis. The study may help small animal practicing veterinarians counseling clients regarding treatment options and outcome after cruciate rupture.