gms | German Medical Science

Objectives: Conventional cementless stems have demonstrated excellent clinical and radiographic results in the long term. However, they could cause significant reduction of the trochanteric bone stock, long stem in the femoral shaft with thigh pain and proximal stress shielding. GTS is a new short stem aiming to spare the trochanteric region and limit the invasion of the femoral shaft in primary total hip replacement (THA). In this single-center case series, the clinical and radiographic results of GTS stem at minimum 6 years of follow-up were evaluated.

Methods: From January to December 2010, 414 patients (439 hips) who underwent primary THA with a mean age of 58 years (range 20-80) were prospectively enrolled. Because of 51 patients (53 hips) were lost to follow-up, 363 patients (M:F=204:159) (386 hips) were available for clinical and radiographic assessment. Preoperative diagnosis was primary osteoarthritis (73%), osteoarthritis secondary to hip dysplasia (16%), post-traumatic arthritis (5%), avascular necrosis of the femoral head (4%) and other (2%). The mean follow-up was 74.8 months (range 72-80). The Harris Hip Score (HHS), heterotopic ossification, osteolysis, radiolucencies, and stress shielding were assessed. Survivorship analysis was performed with revision for any reason and stem aseptic loosening as the endpoint.

Results and Conclusion: The Harris Hip Score increased from 39.4±5.4 preoperatively to 97.3±8.2 postoperatively (p<0.0001). No patient reported thigh pain or clicking/squeaking sounds coming from the prosthesis. Clinical picture after surgery was rated as very satisfactory and satisfactory by 73% and 18% of patients, respectively. At radiographic follow-up, no hips showed stress shielding. Cortical hypertrophy in the femoral shaft was detected in 9 (2.3%) hips. Heterotopic ossification was found in 49 (12.7%) hips, but none required surgical removal. Varus positioning (3°-5°) of the stem was reported in 48 (12.4%) hips. Intra-operative peri-prosthetic fractures were reported in 6 (1.5%) hips. With an average follow-up of 74.8 months, 8 (2%) out of 386 hips underwent further surgery, but only 2 (0.5%) out of 386 hips underwent revision of the stem because of aseptic loosening. The survival rates at 6 years with revision for any reason and for stem aseptic loosening were 98% and 99.5%, respectively.

In conclusion, GTS stem provides excellent clinical and radiological findings in patients undergoing primary THA at minimum 6 years of follow-up.