The reconstruction techniques and mid-term clinical outcomes of hip revision for acetabular bone defect after total hip arthroplasty

Abstract

Objective: To analyze three reconstruction techniques and mid-term clinical outcomes of hip revision for acetabular bone defect after total hip arthroplasty (THA). Methods: This is a retrospective case series study. Included in the study were 109 patients (109 hips) with acetabular bone defect after THA reconstructions in hip revisions from January 2015 to December 2021 in the Senior Department, Forth Medical Center of Chinese People's Liberation Army General Hospital and the Department of Orthopaedics, First Medical Center of Chinese People's Liberation Army General Hospital. According to the preoperative simulated surgeries and different bone defect reconstruction techniques, all patients were divided into a normal cup group, an augment group or a triflange group,respectively. There were 54 patients (54 hips) in the normal cup group, reconstructed with the uncemented porous metal cup (including Jumbo cup), with 23 males and 31 females, aged (59.6±9.9) years (range:32 to 76 years); 44 patients (44 hips) in the augment group, reconstructed with the individualized three-dimensional (3D) printed porous metal augment and uncemented porous metal cup, with 18 males and 26 females, aged (52.8±13.6) years(range:17 to 76 years); 11 patients (11 hips) in the triflange group, reconstructed by the individualized 3D printed porous metal triflange cup, with 5 males and 6 females, aged (59.4±11.2)years (range: 43 to 78 years). Radiographic results, including rotation center height, rotation center offset, and leg length discrepancy (LLD) and clinical results, including Harris hip score (HHS) and visual analogue scale(VAS) were evaluated outpatient at 3, 6, 12 months after the operation and annually thereafter. The last follow-up was completed in March 2024, and all parameters at the last follow-up and before the operation were compared. Paired t test and repeated measurement ANOVA were used for the radiographic and clinical parameters before and after the operation. Results: All hip revisions for patients with acetabular bone defect after THA were completed and followed for more than two years. The follow-up time of the normal cup group was (6.5±1.7) years (range: 2.8 to 9.3 years), and that of the augment group was (6.0±1.3) years (range: 3.5 to 9.0 years). The follow-up time of the triflange group was (2.8±0.6) years (range: 2.0 to 3.8 years). At the last follow-up, the rotation center height, rotation center offset and LLD of 54 hips in the normal cup group were (24.2±5.6)mm, (29.1±5.5) mm and (4.6±3.3)mm, respectively, and the rotation center height and LLD were significantly lower than those of the preoperative hips (t=9.671, P<0.01; t=6.073, P<0.01). In the augment group, the rotational center height, the rotation center offset and the LLD of 44 hips were (22.4±9.0) mm, (25.4±5.5) mm and (6.0±4.0) mm, respectively, which were significantly lower than those of the preoperative hips (t=9.071, P<0.01; t=11.345, P<0.01; t=4.927, P<0.01). In the triflange group, the rotational center height, the rotation center offset and LLD of 11 hips were (22.7±6.0) mm,(30.9±8.0) mm and (5.3±2.2) mm, respectively, and the rotation center height and LLD were significantly lower than those of the preoperative hips (t=2.716, P=0.022; t=6.226, P<0.01). At the last follow-up, fractures occurred in 3 patients and dislocation occurred in 1 patient in the normal cup group, and fracture reduction and closed reduction were administered under anesthesia, respectively. In the augment group, dislocation occurred in 1 patient and open reduction under anesthesia was performed. The HHS and VAS of the three groups improved significantly after surgery and the differences were statistically significant(all P<0.01). There was no complication in the triflange group. The X-ray at the last follow-up showed that all prostheses and augments were in stable positions and no loosening or migration was observed. Conclusions: For patients with acetabular bone defect after THA undergoing hip revisions, preoperative surgical simulation and rehearsal could help surgeons choose convenient and efficient reconstruction techniques. The targeted selection of Jumbo Cup, individualized 3D printed metal augment, and customized triflange cup could achieve satisfactory clinical outcomes.