Accuracy of templating the acetabular cup size in Total Hip Replacement using conventional acetate templates on digital radiographs.

OBJECTIVE: Templating of the acetabular cup size in Total Hip Replacement (THR) is normally done using conventional radiographs. As these are being replaced by digital radiographs, it has become essential to create a technique of templating using digital films. We describe a technique that involves templating the digital films using the universally available acetate templates for THR without the use of special software. MATERIALS AND METHODS: Preoperative digital radiographs of the pelvis were taken with a 30 mm diameter spherical metal ball strapped over the greater trochanter. Using standard acetate templates provided by the implant company on magnified digital radiographs, the size of the metal ball (X mm) and acetabular cup (Y mm) were determined. The size of the acetabular cup to be implanted was estimated using the formula 30*Y/X. The estimated size was compared with the actual size of the cup used at surgery. RESULTS: Using this technique, it was possible to accurately predict the acetabular cup size in 28/40 (70%) of the hips. When the accuracy to within one size was considered, templating was correct in 90% (36/40). When assessed by two independent observers, there was good intra-observer and inter-observer reliability with intra-class correlation coefficient values greater than 0.8. CONCLUSION: It was possible to accurately and reliably predict the size of the acetabular cup, using acetate templates on digital films, without any digital templates.

Tibiocalcaneal arthrodesis using a simple external fixator.

Tibiocalcaneal arthrodesis has been a salvage option for conditions with extensive loss of the talar body. In conditions that preclude the use of internal fixation, external compression arthrodesis has been the preferred technique to achieve fusion about the hindfoot. Since Sir John Charnley elucidated the technique of compression arthrodesis using compression clamps, various modifications and techniques of external compression arthrodesis have been described. Various clinical and biomechanical studies have established the superiority of triangular transfixation in external compression arthrodesis. We have described a simple technique of compression arthrodesis after the principle of triangular transfixation using easily available hardware from Ilizarov instrumentation. This technique is relatively inexpensive in terms of the cost of the materials, uses a modular construct, and allows multiplanar correction of the hindfoot. It can be used intraoperatively to distract the hindfoot joints, especially in the presence of fibrosis and poor skin conditions. We believe this device can be a reasonable alternative to the conventional external fixation techniques for tibiocalcaneal arthrodesis.

Managing skin necrosis and prosthesis subluxation after total knee arthroplasty.

Skin necrosis and prosthetic subluxation are dreaded complications after total knee arthroplasty. It can result in deep infection with subsequent failure of prosthesis. The incidence of infection in patients with rheumatoid arthritis who undergo knee arthroplasty is high when compared to patients with primary osteoarthritis. The gastrocnemius muscle flap has been described for cover of proximal tibia and tendon loss because of malignancy and has been used as a bridge graft in trauma patients with patellar tendon loss. We describe a patient with total knee arthroplasty with anterior knee skin necrosis and prosthesis subluxation because of attenuation and loss of continuity of patellar tendon. This was managed by using gastrocnemius bridge grafting. Here, the gastrocnemius bridge graft was used as a soft tissue cover as well as a dynamic anterior stabilizer for the prosthesis.