Purpose: Medial Opening Wedge High Tibial Osteotomy (MOWHTO) is a joint preserving procedure of the knee. Currently we understand the anatomical changes occurring in the varus/valgus plane, but our understanding of other anatomical changes are limited. The objective of this study is to determine immediate anatomical changes occurring about the knee following MOWHTO. Our hypothesis is that anatomical changes occur in all planes of motion. More specifically, we hypothesize that posterior tibial slope is increased and patellar height is decreased immediately following the osteotomy.

Methods: This study was prospective in design. Patients with knee OA were evaluated according to strict inclusion and exclusion criteria. Pre-operative clinical assessment, radiographic evaluation, and patient assessment scores were performed. Intraoperatively, patients had radiostereometric analysis (RSA) beads placed in a predetermined pattern. Intraoperative radiographs were taken. The MOWHTO was then performed. A second radiograph was then taken following the osteotomy. The radiographs were analysed using dedicated RSA computer software to determine anatomical changes.

Results: Eleven patients were included in this study. Average age was 50 years. Mean error and condition number were 0.70 and 74 respectively, indicating highly accurate and reliable results. Analysis of the proximal tibia showed an average valgus correction angle of 8.69 degrees. The average osteotomy size was 12.5mm (9–17.5). Posterior tibial slope increased on average by 2.07 degrees (+5.91–−1.56). Analysis of the patella revealed anatomical changes occurred in all planes. However, the only consistent alteration was a decrease in patellar height by an average of 8.16mm (1.79–13.17). Additionally, there was a consistent increase in patellar tendon length by 5.30mm (2.38–7.34).

Conclusions: Using RSA in MOWHTO for the first time, we were able to demonstrate a useful and accurate measurement tool for this procedure. We found there were many immediate anatomical changes following MOWHTO that are inconsistent and not well understood. There were, however, several anatomical changes that remained consistent among all subjects. Patellar height decreased, patellar tendon length increased, and posterior tibial slope demonstrated an average increase.

Purpose: To clinically and radiologically evaluate medium term outcome of a patient cohort age 55 years or older at the time of medial opening wedge high tibial osteotomy (MOWHTO).

Methods: Between January 1997 and January 2003, 60 patients (52 males) underwent 66 MOWHTOs. Following a systematic chart review 56 returned for follow up. Outcomes measures were KOOS, LEFS, SF-12, Cincinnati, Tegner scores, a new activity score and physical examination. Routine knee and long leg standing radiographs were compared to pre and early postoperative radiographs.

Results: Thirteen patients were not assessed further, 6 (7 MOWHTOs) had undergone total knee arthroplasty (TKA), 3 had passed away and 4 were lost to follow up. Thus the probability of survival (not converting MOWHTO to TKA) was 0.966 at 3 years, 0.927 at 4 years and 0.878 at 5 years. Quality of life, functional status and general health of the remaining 47 patients (52 HTOs) with a mean age of 62 years (55–75) at the time of surgery were assessed. At a mean follow up of 62 months (26–98), on the author’s activity score, 83% performed at least one high impact activity at moderate to high intensity an average of 4–7 times weekly and 6% did not participate in any sport. Average participation in activities/sports was 3 per person at a participation level of 4.6 (Tegner). The mean Cincinnati score was 75% (SD=23, 14–95%). Mean scores for the KOOS and LEFS were 66% (SD=22,7–99%) and 49 (SD=18, 5–80) respectively. The mean physical component score of the SF-12 was 42 (SD=11, 21.7–60.4) and the mean mental component score, 54 (SD=11, 26–68). Seventy–two percent were fully weight bearing by 3 months. There were 6 revisions performed for a combination of delayed and non-unions.

Conclusions: MOWHTO remains a viable alternative for patients over the age of 55 with knee osteoarthritis and varus malalignment who would otherwise be candidates for arthroplasty and particularly for those wishing to maintain or regain a high level of activity.

Thirty-six patients with anterior cruciate ligament (ACL) insufficiency and varus malalignment were treated with combined ACL reconstruction and medial opening wedge high tibial osteotomy (HTO). Average follow-up was twenty-five months. All patients had improved ligamentous stability and twenty-five patients returned to full activities. Osteotomy union rate was 100%, mechanical axis angle was corrected from six degrees varus to neutral and the mechanical axis deviation was corrected from 2cm medial to 1cm lateral. We experienced four complications, including one deep infection. Combining ACL reconstruction and HTO simultaneously accomplishes a ligamentously stable knee with corrected alignment, allowing patients to return to activity.

To determine clinical outcome after combined ACL reconstruction and medial opening wedge high tibial osteotomy (HTO).

ACL reconstruction with medial opening HTO can be a beneficial procedure in properly selected patients presenting with complaints of both pain and instability. Correction of varus mal-alignment may provide protection for articular cartilage and improve joint stability.

Concomitant medial opening HTO performed at time of ACL reconstruction allows patients to return to activities after one procedure with a ligamentously stable knee, corrected alignment, and potential protection of articular cartilage.

Thirty-six patients who underwent ACL reconstruction along with medial opening HTO were retrospectively evaluated postoperatively at an average of twenty-five months.

Average age was thirty-seven years at time of surgery. All patients were recreationally active. Pre-operatively all patients had knee pain and instability, varus angulation, and twenty-two patients had previous knee surgery. Semitendinosus/gracilis grafts were used in all patients, and osteotomies were fixed with Puddu plates. Postoperatively patients had improved ligmentous stability with radiographic and clinical evidence of osteotomy healing, and all but nine patients have returned to full activities. We experienced four complications: one ACL failure, one case of anterior laxity with tibial tunnel widening, and two infections. On average, MAD was corrected from 22mm medial to 10mm lateral; mechanical axis angle was corrected from 6.4 degrees of varus to 0.2 degrees of valgus; tibial slope was increased from 9.1 degrees to 10.3 degrees, and patellar height ratio was decreased from 0.9 to 0.8.