Introduction: The anatomic abnormalities associated with the dysplastic hip increase the complexity of hip arthroplasty, in addition previous femural osteotomy can deformate proximal femur.

Despite the fact that uncemented cup and stems are specifically designed for dysplasia to recover the true acetabular region in Crowe IV and sometimes Crowe III additional surgical procedure are required.

Purpose of the study is to analize surgical procedure and then reconstruction options on severe hip dysplasia.

Materials and methods: From 1984 till today 2308 cases of arthroplasty were performed in dysplastic hip, 565 cases have a previous femoral osteotomy; out of these 2308 cases 128 cases need treatment for corrections of femural side deformity.

64 cases were subjected to a greater trochanteric osteotomy. In 12 cases proximal femural shortening was associated. In 9 cases rotational abnormality and shortening were controlled with a distal femur osteotomy.

55 cases were treated by a shortening subtrochanteric osteotomy that allows corrections of any deformity. Only uncemented stems were used and in the majority of cases a specific device for displastic hip (Wagner Conus produced by Zimmer).

Discussion: Long-term results in these patients are steadily inferior to that in the general population (70% survival at 15 yrs). On femural side early failures are the reflection of learning curve and are due to insufficient fixation of the osteotomy.

Despite this, the more promising outcomes are concerning shortening subtrochanteric osteotomy with uncemented stem but only early and mid-term data are available.

Unstable knee caused by an axial deformity mainly occurs in serious valgus cases, which is the result of a femoral external hypoplastic condylus defect and often seen in association with marked debris of the tibial plate and bone –loss. Tibial rotation related to the deficit causes lateral patellar subluxation, and soft tissue retraction fixes the deformity while the preconditions for an anteromedial ligamentous laxity are being created. On replacement the deformities develop because of bone-stock defects as well as ligamentous defects, which are often secondary to debris and/or to primary component misrotations.

In primary surgery the approach is medial for varus and lateral for valgus, in order to help the release. We use the GAP technique to implant semibonded prostheses. In revisions the previous approach is always followed. From 2000 to 2003 52 LCCK Zimmer were implanted. Tuberosity detachment was required in 20 cases.

The increase in TKS was significant.: from 40 to 180. The radiographic alignment supported by taproots centrage is excellent, and there are no signs of radiographical mobilisation in any of the cases.

There were two cases of intolerance, with decubitus of a screw utilised for the tibial tuberosity synthesis. A flexion-extension defect had to be repaired afterwards by surgery and two cases of endostal reaction to the tibial taproot were observed.

Despite the difficulty of treated cases, results appear promising; the combination between prosthesis type and GAP technique confers high stability to the system.