Medial open wedge (MOW) and lateral closed wedge (LCW) osteotomies are established methods to treat medial gonarthritis. Advantages and differences in the outcome of the two techniques have been discussed controversially and there is still no precise recommendation for either technique. We now aimed to assess the effect of each technique on tibial slope (TS), patella height (PH) and leg length discrepancy.
In a study of 50 consecutive cases of MOW and 50 of LCW osteotomies were registered. The decision for either technique was made pre-operatively according to an algorithm. Demographic data, operation procedures (time of operation, correction angle, torsional correction) and measurement of patellar height, tibial slope, leg length discrepancy, clinical outcome after one year and bone and wound healing were obtained. Pre- and post-operative values were compared between the two groups.
In absence of randomization demographic data demonstrate comparability of the two groups. No difference in bone and wound healing, time of operation and clinical outcome was seen. In the MOW group PH decreased significantly, no relevant alteration of PH was detected in the LCW group. In the latter group a statistically significant decrease of TS compared to a slightly decrease in the MOW group was recorded post-operatively. A significant leg lengthening with the MOW and shortening of the leg with the LCW method can be achieved.
With respect to similar results in operating procedures, bone and wound healing and clinical outcome decision making factors for either technique should be leg length discrepancy and torsional deformities. Changes of PH and TS have to be known and may influence the technique of osteotomy in cases of patella infera / alta or borderline PH.
An algorithm for valgus high tibial osteotomies based on TS, PH and leg length discrepancy may be proposed.