[Value of alignment osteotomy of the proximal tibia in the endoprosthesis period]

To evaluate the value of high tibial osteotomy in times of growing numbers of endoprostheses we compared our personal with other results of this method as well as of the unilateral sledge prosthesis.

Between 1972 and 1993 the high tibial osteotomy as described by Coventry was performed in 105 patients. 98 patients could be examined clinically-radiologically and evaluated with a questionnaire. The indication for surgery was given in patients with unilateral arthrosis without affection of the retropatellar joint and without significant ligamentous instability. The varus deviation was in no case more than 10 degrees. The average follow-up for the clinical-radiologic examination was 9.4 years.

77 patients (78.6%) were satisfied with the outcome of the surgery. Here it was seen that neither age nor pain or instability had an influence on this judgement. The walking distance on the other hand had a significant influence. Stair climbing and range of motion were significantly important as well. 23 patients gave the judgement "excellent", 31 "good", 36 "satisfactory" and 8 patients were "not satisfied". A significant influence of patient age on the judgement could not be proven. The division in the Japanese Score showed "good" results in 14%, "moderate" in 81% and "poor" in 5%. 13 knee joints (13.3%) were absolutely pain-free and in 67 cases (68.4%) there were a definite pain reduction. A significant correlation between the preoperative axis deviation and pain could not be found. An average flexion of 97.5 degree and an extension deficit of 3.3 degree on average was seen. A significant difference of range of motion dependent on age groups could not be found. In 42 knees (42.9%) the lateral ligaments were clinically stable, in 35 cases (35.7%) there was a first degree lateral stress gap and in 21 cases (21.4%) there was a second degree lateral instability. A significant correlation between the instability and age or pain could not be proven. 13 revision surgeries including 9 endoprosthesis implantations were performed.

The study showed a high level of satisfaction with an exact surgical indication. When seeing the growing number of implanted uni- or tricompartmental endoprostheses the procedure of tibial osteotomy can be suggested for patients with unilateral arthrosis without retropatellar arthrosis, with an axis deviation less than 15 degrees, with unaffected cartilage of the contralateral compartment and without ligamentous insufficiency independent of patient age.