Abstract
An extra articular correction may be necessary in osteoarthritis with an important post traumatic or congenital deformity. In the last 5 years we performed 11 TKR associated with a tibial (9 cases) or a femoral Osteotomy (2 cases), in one time surgery. The average intra osseous deformity was 14°. The technical problems are different in varus and valgus knees.
1- Which type of osteotomy ? In varus knees with a tibial deformity (6 cases) we use a hight tibial valgus osteotomy with opening wedge. Pre operative planning with long standing X rays allows precise determination of the amount of correction needed. A rigide wire, driven up to the fibular head, is placed. A provisional wedge of the desired size (degree of correction) is maintened temporarily by a staple, which will be removed later. Once the correction has been performed and maintened, the standard instrumentation to implant the prosthesis is used. In valgus knees with a tibial deformity (2 cases) a hight tibial closing wedge osteotomy, and in valgus knees with a femoral deformity (2 cases), a low femoral closing wedge osteotomy, are used. In all cases a medial approach without any release and without fibular osteotomy is performed.
2- Which kind of prosthesis?
Two degrees of constraint are possible in fonction of particular needs.
Most of the time, a non-constrained PS articular implants will be used and when more constraint will be needed (in lateral instability), CCK-type articular surfaces will be choised.
In all cases, a stem will have to be, associated with the osteotomy (tibial or femoral). Different diameters will allow a good press-fit and if necessary, an offset stem will be used.
3- Associated osteosynthesis or not? Stability provided by the press-fit stem may allow not to use an osteosynthesis in most than 50% of cases. If a doubt remains about stability, a small plate can bee added on the medial tibial side of the tibia.
4- Which immediate post-op follow-up?
Full weight bearing will be immediate. A splint will be used only for walking during six weeks. A standard rehabilitation protocole will be followed. In our 11 patients with a short follow up (1 to 5 years) complications consisted in one hematom and one phlebitis. Post-operative alpha angle was 96° and beta angle 91°. TKR with an associated osteotomy seems to be a possible alternative when osteoarthritis is associated with an important extra articular deformity.
The abstracts were prepared by Nico Verdonschot. Correspondence should be addressed to him at Orthopaedic Research Laboratory, University Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
