A prospective series comprising 52 knees in 48 patients suffering from medial or lateral unicompartmental gonarthrosis and treated by means of high tibial osteotomy shows, by comparing mechanical axis (MA) O ยฐcorrected knees, how important is the overcorrection of the MA into valgus in medial osteoarthritis The clinical results were significantly correlated to overcorrection, the results 2 years postoperatively being better than those obtained at a follow-up 1 year after the operation Of the results, 82 % were good within a limit of ยฑ 3 ยฐafter 2 years, while only 77 % were correspondingly good 1 year postoperatively In lateral gonarthrosis overcorrection was not as good, but there was a mean overcorrection of + 2 ยฐ, and with respect to this overcorrection, the results were quite acceptable The results were directly correlated to the opening up of the joint space affected ( 80 %) and diminution or disappearance of subluxation, 1/3 being O ยฐpreoperatively, /2 postoperatively in medial gonarthrosis In lateral gonarthrosis, subluxation was increased, with 2/3 being O ยฐpreoperatively, 1/3 being O ยฐpostoperatively. The extension deficit in varus knees significantly diminished after valgus osteotomy; the change in valgus knees was also evident but not significant The mean value of extension deficit was below 5 in all cases at the 2 years' follow-up examination However, 95 % of all patients showed good or fair results after a follow-up period of 2 years.
A typical sign of hemiarthrosis of the knee is progressive destruction of the articular cartilage, leading to