Primary total hip arthroplasty using custom-made acetabular implants in patients with high hip dislocation : surgical technique and results.

Aims: Despite good results of using uncemented press-fit cups in patients with high hip dislocations (type C as per the Hartofilakidis classification), there are reports of loosening of these components. To improve the results on the acetabular side in patients with high hip dislocations, we used custom-made acetabular implants (CMAIs). The aim of this study was to evaluate the outcomes after total hip arthroplasty (THA) using CMAIs in patients with high hip dislocation. Methods: We retrospectively analyzed the results of primary THA using the CMAIs in 58 hips (52 patients) from November 2017 to December 2019. All surgeries were performed using the femoral shortening osteotomy technique described by Paavilainen. Type C1 and C2 dislocations were observed in nine and 49 hips, respectively. The presence of various complications, functional results using the Oxford Hip Score (OHS), patient satisfaction, radiological parameters, and positioning of CMAIs were assessed. Results: The mean follow-up period, including radiological follow-up for all 58 hips, was 5.2 years (4.2 to 6.3; SD 0.71). Patients demonstrated statistically significant improved functional outcomes according to the OHS (preoperatively 16.9 and postoperatively 38.5; p < 0.001). Four hips were revised: two hips due to dislocations, the cause of which was impingement of the greater trochanter due to malposition of the distally advanced greater trochanter after osteotomy. One hip was due to nonunion of the distally advanced greater trochanter after osteotomy, and one hip due to pain resulting from iliopsoas impingement caused by contact of the CMAI flange with the iliopsoas muscle. There were no radiological signs of loosening of the CMAIs. Any deviation of the CMAIs from the planned position was noted. Conclusion: This preliminary study demonstrated that CMAIs may offer good bone fixation in patients with high hip dislocation; however, further biomechanical studies are needed to evaluate the use of CMAIs in terms of osseointegration, additional screw fixation, and to determine the effect of deviation of CMAIs from the planned position on clinically relevant complications.