Introduction: ‘Fit and fill’ of the femoral component was originally thought essential for stability of cement-less stems. However, the Zweymuller stem was designed for ‘fit without fill’,(particularly flat tapered stem) and remains highly successful since its inception in 1979. We have performed primary cementless THA with the Profemur Z system (Wright Medical Technology, Inc.) mainly for dysplastic hip. The concept of Profemur Z stem with a modular neck system is the same as the Zweymuller grit-blasted titanium femoral stem. Traditional templating for dysplastic hips often led to errors in sizing, cup positioning and femoral stem direction. A CT-based surgical planning system called Hip-Op is a three dimensional planning software program that uses DICOM images to represent the relevant anatomical objects by means of multiple views. The purpose of this study was to evaluate the utility of the Hip-Op system to accurately predict implant size, insertion angle and the fixation manner of the femoral stem.

Materials and methods: One hundred and three non-selected, consecutive THA in 96 patients were performed as primary cementless THA with the Profemur Z system by the same surgeon. There were 81 women and 15 men in this group, with a mean age at surgery of 63 years (range 35 to 87 years). Postoperatively, the predicted implant sizes planned with Hip-Op system and with standard X-ray templates were compared to the actual components selected at the time of surgery. Clinical evaluation was done by using Harris Hip Score (HHS). The femoral stem was evaluated in both the anterior posterior and lateral projections of the radiographs. Insertion angle and the fixation manner of the femoral stem were also examined postoperatively using X-ray and CT.

Results: 3D templating with Hip-Op system accurately predicted the exact size of the femoral component 65% of the time, was within 1 size 96% of the time and within 2 sizes 100% of the time. Acetabuli were correctly predicted 80% of the time, within 1 size 98% and within 2 sizes 100% of the time. Conventional templating predicted the exact size 48% of the time in femoral components, and 66% in acetabuli, within 1 size 76% and 82%, within 2 sizes 89% and 92%, respectively. The average preoperative HHS was 46.3 points and the latest HHS was 83.2 points on average. Three patients required slow physiotherapy due to greater trochanteric fractures. Two patients were suffering from anterior dislocation. There was no femoral component subsidence. The insertion angle from neutral position of the stem was 0.4 degree in A-P view, and 1.6 degree in profile view. The fixation manner of the Zweymuller stem in the canal was obtained by contact with the four corners of the stem in 6.7%, three corners in 16.7%, two corners in 70%, respectively.

Discussion: The Zweymuller stem design provides primary axial stability through its dual longitudinal taper and primary rotational stability through contact with the corners of the stem to cortical bone in the canal. This study clearly shows the advantages of CT-based 3D templating over conventional X-ray templates. The surgical planning performed with Hip-Op system is accurate and useful, especially for dysplastic hip.

The application of arthroscopic procedure for osteoarthritic knee is limited to rather initial stages of the disease. Here we report the results of new arthroscopic procedure, which was named arthroscopic posteromedial release, applied to relatively severe cases of medial type osteoarthrits (OA)

Forty-eight knees of 46 patients of OA knees with flexion contracture were treated with arthroscopic posteromedial release. Thirty-two were female and 14 were male. All the patients had been treated conservatively beforehand. The mean age of the patients was 71.6 (range, 47 to 84 years), the average range of motion was 13 to 129 degrees. Only one case was classified stage II in Kellgren Lowrence x-ray classification, 13 and 34 cases were stage III and IV respectively. The average femoro-tibial angle was 183.4+-4.4 degrees.

In surgery, we release the joint capsule along with the medial tibial condyle, arthroscopic debridement including medial meniscentomy was performed at the same time. If some cases, medial collateral ligament was cut transversely to obtain enough joint space. We use hyaluronan intra-articularly once a week for 5 weeks postoperatively. Patients were examined at 3,6,12,18 and 24 months after surgery and evaluated subjectively and objectively with the rating system of Japanese Orthopaedic Association knee score (JOA score). Clinical results were also classified excelletn, good, fair and poor by our criteria.

Eighty-three per cent (40 knees) of patients were satisfied at their last follow up. Sixty-seven percent (32 knees) of the patients were excellent or good. Six knees were converted to TKA because of their persistent knee pain. Twenty-eight knees complained of night pain pre-operatively, but only four of them complained of it postoperatively

Considering that most of the patients in this series were grade IV in x-rays and their joint surface of medial compartment showed large eburnation both femur and tibia, TKA is most preferable treatment conventionally. But our results showed this arthroscopic technique was one of the applicable choices for severe OA knees.