Lateral parapatellar approach with tibial tubercle osteotomy for the treatment of non-correctable valgus knee osteoarthritis: a retrospective clinical study.

Background: The aim of this retrospective study was to evaluate the efficacy of a lateral parapatellar approach combined with a tibial tubercle osteotomy (TTO) in patients undergoing total knee arthroplasty (TKA) with non-correctable valgus knee osteoarthritis.

Methods: We studied 53 consecutive patients (57 knees) who had a primary TKA via lateral parapatellar approach with a global step-cut "coffin" type TTO over a 10-year period. All patients had non-correctable grade II valgus deformity according to the Ranawat classification. The average age of patients was 71 years (45 to 77) and the mean follow-up was 39 months (20 to 98).

Results: Post-surgery, there was a significant improvement in knee extension (p=0.002), flexion (p=0.006), Knee Society Pain and Function Scores (p<0.001) and WOMAC Osteoarthritis Index (p<0.001). The tibiofemoral angle changed from a preoperative median value of 11 deg (10 to 17) to a postoperative value of 3.75 deg (0 to 9). Congruent patellar tracking was observed in all cases. All but one osteotomy united in a median period of 16.7 weeks (9 to 28) and no hardware removal was required. One knee developed infection treated with two-stage reconstruction. A proximal tibial stress fracture also occurred in a patient on long-term bisphosphonate therapy.

Conclusion: Lateral parapatellar approach along with TTO is an effective technique for addressing non-correctable valgus knee deformity during TKA.