Highly accurate acoustical prediction using support vector machine algorithm for post-operative subsidence after cementless total hip arthroplasty

Evaluation of bone integrity around the acetabular cup using noninvasive laser resonance frequency analysis

Resonance frequency analysis (RFA) is valuable for assessing implant status. In a previous investigation, acetabular cup fixation was assessed using laser RFA and the pull-down force was predicted in an in vitro setting. While the pull-down force alone is sufficient for initial fixation evaluation, it is desirable to evaluate the bone strength of the foundation for subsequent fixation. Diminished bone quality causes micromotion, migration, and protracted osseointegration, consequently elevating susceptibility to periprosthetic fractures and failure of ingrained trabecular bone. Limited research exists on the evaluation of bone mineral density (BMD) around the cup using RFA. For in vivo application of laser RFA, we implemented the sweep pulse excitation method and engineered an innovative laser RFA device having low laser energy and small dimensions. We focused on a specific frequency range (2500-4500 Hz), where the peak frequency was presumed to be influenced by foundational density. Quantitative computed tomography with a phantom was employed to assess periprosthetic BMD. Correlation between the resonance frequency within the designated range and the density around the cup was evaluated both in the laboratory and in vivo using the novel laser RFA device. The Kruskal-Wallis test showed robust correlations in both experiments (laboratory study: R = 0.728, p < 0.001; in vivo study: R = 0.619, p < 0.001). Our laser RFA system can assess the quality of bone surrounding the cup. Laser RFA holds promise in predicting the risk of loosening and might aid in the decision-making process for additional fixation through screw insertion.

Over ten-year follow-up results of a prospective and consecutive series of primary total hip arthroplasty with an original cementless total hip prosthesis

PURPOSE

High survival rates up to ten  years have been reported for non-cemented hip replacements. Publications beyond ten years have more diverse conclusions. To study the long-term survival of uncemented total hip replacement (THR), we examined a series of 125 THR, all with a minimum follow-up of ten  years.

METHODS

This is a prospective study of 203 patients operated for coxarthrosis between 2007 and 2011, by six senior surgeons. The original ellipsoidal stem and the impacted acetabulum were systematically cementless; the acetabulum had either a fixed ceramic or polyethylene insert, or a dual-mobility insert. At the date of the follow-up check, 44 patients were deceased and 34 patients were lost to follow-up. This left 125 complete files for our study.

RESULTS

They were a revision of the cup in four cases and a revision of the femoral stem in three cases (3.4%). The Kaplan-Meier cumulative survival rate of the THR, by considering revision for any reason as endpoint, at ten  years (120 months) is estimated at 96.6% (CI 92.7-98.7). Radiologically, on 86 analyses (68.8%) at ten  years and more reported, no significant evolution of the appearance of the cancellous bone around the acetabular cup was noted, nor any ossification. Some periprosthetic osteogenesis reactions were noted around the 1/3 distal but no periprosthetic edging.

CONCLUSION

In this minimum ten-year follow-up study, a cementless THR with a straight ellipsoidal cementless stem and a press-fit cup provides excellent implant survival and high patient satisfaction. (Clinically felt minimal difference.).