High correction accuracy and low complication rate of double-level knee varization osteotomy using the free-hand technique: A single-centre retrospective analysis of 26 cases.

BACKGROUND

Valgus knee malalignment with isolated lateral compartment osteoarthritis (OA) represents a challenging condition to the orthopaedic surgeon. In the young active patient, realignment osteotomy represents an appealing solution to manage the presented problem and lay a more neutral alignment for future conversion arthroplasty. Nevertheless, in substantial or bifocal (femur and tibia) deformities, double-level knee osteotomy should be considered to maintain joint line obliquity and avoid introducing secondary joint deformities.

METHODS

A retrospective review of a prospectively maintained single-centre database of 1170 knee osteotomies was undertaken. Twenty-six patients with bifocal (femur and tibia) valgus malalignment and isolated lateral compartment osteoarthritis who had double-level osteotomy corrections (high tibial osteotomy (HTO) and distal femoral osteotomy (DFO)) were included. Multiple PROMs were recorded preoperatively and serially postoperatively. This included the Knee Injury and Osteoarthritis Outcome index scores, the Oxford knee score, Oxford Knee Score - Activity and Participation Questionnaire, the Western Ontario and McMaster University Scores, the Visual Analogue Scale for health and pain, and the EQ5D. EQ-5D stands for EuroQol 5-Dimension; it is a standardized instrument for measuring health-related quality of life (HRQoL). All lower limb alignment indices were recorded pre-and postoperatively. The rates of osteotomy revision, conversion to arthroplasty, complications, and 10-year survivorship were recorded.

RESULTS

A total of 26 varization double-level osteotomy cases were followed up to a mean of 10.7 ± 3.5 years. This comprised 42.3 % males and 57.7 % females, with a mean age of 45.5 ± 10.9 years and a mean BMI of 30.9 ± 5.7 kg/m. The mean planned correction angles for HTO and DFO were 7.4 ± 2.7° and 7.3 ± 1.9°, respectively. Postoperatively, the mean mechanical tibiofemoral angle improved from 12.5 ± 4.4° valgus to - 1.5 ± 2.6° varus, the mean MPTA improved from preoperative 93.8 ± 3.6° to postoperative 87.3 ± 2.6°, and the mean Mikulicz point improved from 105.7 ± 20.6 % to 39.9 ± 15.5 % (all P-values < 0.001). A high correction accuracy was reported for the mTFA, mLDFA and MPTA of 1.1 ± 1.3°, 1 ± 2.7°, and 0.7 ± 2.8°, respectively. The correction accuracy for the Mikulicz was 5 ± 15.6 %. All PROMs significantly improved at all time points with the most significant improvement noted at 24 months follow up (all P-values < 0.001). The rate of osteotomy revision was 3.8 %. The overall rate of total knee arthroplasty conversion was 15.4 % at an average of 4.9 ± 2.3 years postoperatively. The complication rate was 7.6 %. The 10-year survivorship was 86.5 %.

CONCLUSION

Varization double-level knee osteotomies for valgus knees, with severe malalignment with bifocal femoral and tibial deformities, improves clinical outcomes and radiological alignment parameters. Free-hand varization DLO demonstrated high correction accuracy with a low complication rate of 7.6 % and survivorship of 86.5 % at 10 years.