The roof step cut: A novel technique for bony reconstruction of acetabular roof deficiency during total hip replacement.

OBJECTIVES: This study aims to present a new technique, the roof step cut (RSC), for acetabular augmentation of hip dysplasia. PATIENTS AND METHODS: Between December 2008 and March 2020, we applied the RSC technique in a total of 48 hips of 41 patients (2 males, 39 females; mean age: 50.1±9.5 years; range, 30 to 75 years) with Hartofilakidis type A, B, C hip dysplasia. The RSC technique uses a L-shaped graft cut from the femoral head. The graft is partially inside the acetabulum and partially on the lateral aspect of the ilium. It is fixed with two screws at a 45° angle allowing simultaneous distalization and lateral covering of the cementless cup. Follow-up was done at six weeks, three months, and annually thereafter using standard pelvis anteroposterior X-ray and function scores. The 99mTc bone scintigraphy examination was also performed at around two weeks, six months, and 12 months postoperatively to evaluate the healing process of the graft. RESULTS: The mean follow-up time was 59.6±25.6 (range, 12 to 109) months. No significant center-edge angle changes and no contiguous radiolucent zones at the bone prosthesis interface were observed at the final follow-up. The single-photon emission tomography (SPECT) showed the activity of the bone graft gradually increased after surgery and became almost the same as the reference area after 12 months. Functional evaluation showed a significant improvement after the operation. No complication directly related to the technique was observed. CONCLUSION: In the short-term follow-up, the RSC technique is a reliable procedure for acetabular augmentation of hip dysplasia, providing enough coverage for the cementless cup and assuring proper stability.

The biological and biomechanical comparison of two bulk bone graft techniques used in case of dysplastic acetabulum.

BACKGROUND: The incorporation of bulk bone grafts in the replacement of dysplastic acetabulum is determined by the biological environment of the recipient site, the size of the contact surface, and the stability of the osteosynthesis used. Based on these, the present study compares the Harris acetabular plasty used routinely by us with the Radojevic L-shaped graft technique. METHODS: For our measurements, we used 20 hemi-pelvises removed from 10 cadavers. In 10 cases, acetabular plasty according to Harris, in 10 cases Radojevic L-plasty, was performed. The biological environment was analyzed; with geometric calculations, the contact surface was determined, and with a material testing apparatus, the primary stability of the osetosynthesis was measured. For the measurements, a new method was developed. RESULTS: The Radojevic technique provides a better biological environment for graft ingrowth. The contact surface is nearly twice as much as in Harris plasty. No significant difference was found in the primary stability of the osteosynthesis used. The deviation on the value of the stability measurements is explained by the differences in the bone quality of the cadavers used. CONCLUSIONS: Based on the 3 aspects examined, the Radojevic L-shaped graft technique has similar stability when compared to the Harris acetabular plasty, but provides better biological circumstances and larger graft host bone contact. Based on this, we started using the L-shaped technique in our department.