gms | German Medical Science

Objectives: Total knee arthroplasty (TKA) or Hemiarthroplasty (HA) is mainly used for moderate or severe medial knee osteoarthritis, and High tibial osteotomy (HTO) is used only for mild cases. Because HTO, which is an extra-articular osteotomy, cannot improve the congruency of knee joints. Tibial Condylar Valgus Osteotomy (TCVO), which is an intra-articular osteotomy, was developed to treat moderate or severe medial osteoarthritis of knee joints without any prosthesis.

Materials: One hundred and four knees in 101 patients (12 male and 89 female) with moderate or severe medial osteoarthritis of knee joints were treated with TCVO. Age of them were ranging from 44 to 83 (58.1 years old in average). The follow-up period was 8.5 years in average (ranging from 2 to 18 years).

Methods: In case of TCVO, the osteotomy line starts at an inter-condylar eminence and ends at the medial cortex approximately 4cm distal from the knee joint. The distal end of the osteotomy site was spread until lateral instability of the knee joint disappeared. The osteotomized bone fragments were fixed with Ilizarov External Fixator or a plate, and the spread space was filled with Iliac bone graft. The clinical outcome of TCVO were evaluated by Japanese Orthopaedic Association score (JOA score) and percent mechanical axis (%MA).

Results: JOA score improved from 45.3 ± 7.5 (ranging from 25 to 55) to 81.1 ± 8.2 (ranging from 70 to 100 ), and %MA was 6.8 ± 18.1% in average (ranging from -99.1% to 35.0%) before surgery and 59.2 ± 10.3%. in average (ranging from 19.8% - 80.1%) after surgery.

Discussions: In case of severe medial osteoarthritis, only medial condyles of the femur and the tibia are in contact, which causes lateral instability and diminishes the contact area. We believe that instability and increase of contact pressure causes knee pain and knee malfanction. After TCVO both medial and lateral condyles are in contact, and the knee joint becomes stable and the contact area of the knee joint becomes larger and the contact pressure of the knee joint decreases. The alignment of the lower extremity was improved after TCVO because the lower extremity became valgus after correction.

Conclusions: Intra-articular deformity of medial osteoarthritis of knee joint was well corrected by TCVO, and followings were all achieved by TCVO. 1) Total contact of the knee joint, 2) Improvement of the stability of the knee joint, 3) Correction of the alignment of lower extremity.