[Long-term results of the treatment of medial femoro-tibial gonarthrosis by tibial valgisation osteotomy. Outcome of 93 osteotomies after more than 10 years].

Amongst the 250 tibial valgisation osteotomies performed for medial femoro-tibial osteoarthrosis of the knee between 1970 and 1973, only 93 in 66 patients could be followed up for 10 years or more (10-13 years). The long term outcome of the operation is dominated by frontal angular correction. The radiological and clinical result was regularly satisfactory after ten years only when the valgus was between 3 and 6 degrees. With more than 6 degrees valgus, there was deterioration of the lateral femoro-tibial compartment in all cases. Clinical and radiological results were variable with more than 3 degrees varus and were all the worse when there was considerable persistent varus. However functional impairment of those knees in which correction was inadequate occurred only after a mean latent period of 7 years. It remained slow and moderate, offering the possibility of a new osteotomy in case of failure. This would confirm that tibial osteotomy has at least two actions: a trophic action which disappears at about 7 years and a mechanical action, the importance of which appears in the long term. It is therefore felt that tibial valgisation osteotomy is a sufficiently reliable operation to be proposed in all cases of symptomatic and progressive osteoarthrosis with genu varum. Correction and results are all the more satisfactory when the operation is carried out before flexion deformity or laxity interfere with the accuracy of the correction. A preference for the insertion of a prosthesis may be preferred only in the elderly (the authors preferring the medial unicompartmental type), the principal advantage being to decrease the relatively long period of postoperative immobilisation following osteotomy.