Summary

The paper discusses DJD varus, Ahlback IV cases, advanced intra-articular deformity with flexion contracture and evaluate the correlations between the amount of medial resection - reduction tibial osteotomy and the clinical - functional results.

Abstract

The paper discusses DJD varus, Ahlback IV cases, advanced intra-articular deformity with flexion contracture and evaluates the correlations between the amount of medial resection - reduction tibial osteotomy and the clinical - functional results.

Method

Clinical data for 118 patients operated between December 2016 - December 2017 (same senior surgeon, subvastus approach) was preospectively gathered; 53 cases needed reduction osteotomy (44.9%). Reduction osteotomy was applied as a step in the gap balancing technique of varus knees after removal of obvious osteophytes and release of superficial MCL It was a pre-planned mandatory surgical step.

Results:The study group had a female to male ratio of 6:1, with an average age of 66 years (range, 56-75 years). The degenerative disease evolution ranged from 3 to 10 years (mean, 5.5 years). The BMI was 31.5 ± 5.40 (range 23.8 to 47). The preoperative Knee Society Score (KSS) was poor - median 47 (range 32 to 59) for clinical score and 35 (20 to 40) for the functional score. The range of motion (ROM) of the knee was from 80 to 100. The median HKA angle was 15.5° of varus deformity; 52% had moderate - advanced 10 to 20 degrees of varus, 13.04 % had severe to massive varus (more than 20 deg.)

The operative tourniquet time was 60 to 90 minutes. Postero-stabilized implants were used; preoperative planning went for downsizing the implants, with 7 deg. of valgus distal femoral resection (as suggested by Neyret et al.) and 3 to 5 deg. external rotation. Follow-up visits are programmed at 2, 6 weeks, 3, 6, 12 months and yearly after.

The follow-up duration ranged from 8 to 16 months. The tibio-femoral angle was corrected to 90 ± 4 deg. at 6 weeks after operation (early long leg standing x-rays and clinical follow-up to assess also the status of the medial tibial bone). The lower limb alignment recovered to normal. The X-ray films showed no evidence of evolutive radiolucent line, osteolysis or subsidence. Pearson statistical test was used for analyzing eventual correlations: the amount of osteotomy was related to the BMI (p=0.004) and the preoperative femuro-tibial angle (p=0.001).
The results of KSS were significantly improved to 85 to 90 for clinical score and 80 to 90 for functional score; ROM of the knee was significantly increased to (110 ± 5) deg. at last follow-up. No patients required constrained implants. No additional release of superficial medial collateral or semi membranous was needed. The patients are monitored on a prospective manner and no medial bone resorption was noted.

Conclusions

Reduction osteotomy is an effective procedure for varus knee deformity during total knee arthroplasty. Proper alignment, ROM, and function of knee can be accomplished without extensive medial release in these cases. The magnitude of reduction may be preoperatively assessed on long leg standing digital X-rays. In high BMI cases one may expect larger sized osteotomies.