Modular reconstruction systems based on porous tantalum (PT) prosthetic components have been increasingly used for the treatment of complex acetabular bone defects in revision total hip arthroplasty. We report a novel technique that applies a revision cup as a "super-augment" to form a "double-cup" construct for Paprosky type III defects.

A retrospective review was conducted on revision total hip arthroplasty cases, comparing those treated with double-cup constructs (DC group, n = 48) to those treated with PT shells and augments (PT group, n = 48). All procedures were performed at the same institute between 2017 and 2022. Clinical outcome evaluation utilized the Harris Hip Score, Oxford Hip Score, and the 36-Item Short Form Survey. Preoperative and postoperative radiographic assessments measured hip center of rotation (COR) position and leg length discrepancy. Additionally, postoperative complications and implant survivorship were monitored during the follow-up period.

The clinical outcomes improved substantially in both groups, which showed no significant difference in the Harris Hip Score (P = .786), the Oxford Hip Score (P = .570), and the 36-Item Short Form Survey (P = .691). Compared to the PT group, the reconstruction COR was significantly closer to the anatomic COR (vertical distance: 2.630 versus 7.355 mm, P = .0034; horizontal distance: 1.881 versus -6.413 mm, P < .0001) in Paprosky 3B type defects. Additionally, postoperative leg length discrepancy was less in the DC group (-8.252 versus -1.821 mm, P = .0008). Dislocation was the main complication in the DC group, and only 1 patient received re-revision due to repeated dislocation. The cumulative survival rate of the DC group (100%; 95% confidence interval 100) was better than the PT group (83.4%; 95% confidence interval 70.5 to 98.6) when re-revisions for aseptic loosening were the endpoint (P = .046).

The DC is a reliable revision technique for the reconstruction of Paprosky type III bone defects. Although dislocation remains challenging, the biomechanically superior restoration achieved by this technique lowers the risk of aseptic loosening.

Total hip arthroplasty is a common surgical treatment for elderly patients with osteoporosis, particularly in postmenopausal women. In such cases, highly porous acetabular components are a favorable option in achieving osseointegration. However, further discussion is needed if use of such acetabular components is justified under the condition of normal bone mass.

To determine the features of osseointegration of two different types of titanium implants [3-dimensional (3D)-printed and plasma-coated titanium implants] in bone tissue of a distal metaphysis in a rat femur model.

This study was performed on 20 white male laboratory rats weighing 300-350 g aged 6 mo. Rats were divided into two groups of 10 animals, which had two different types of implants were inserted into a hole defect (2 × 3 mm) in the distal metaphysis of the femur: Group I: 3D-printed titanium implant (highly porous); Group II: Plasma-coated titanium implant. After 45 and 90 d following surgery, the rats were sacrificed, and their implanted femurs were extracted for histological examination. The relative perimeter (%) of bone trabeculae [bone-implant contact (BIC%)] and bone marrow surrounding the titanium implants was measured.

Trabecular bone tissue was formed on the 45th day after implantation around the implants regardless of their type. 45 d after surgery, group I (3D-printed titanium implant) and group II (plasma-coated titanium implant) did not differ in BIC% (83.51 ± 8.5 vs 84.12 ± 1 .73; P = 0.838). After 90 d, the BIC% was higher in group I (87.04 ± 6.99 vs 81.24 ± 7.62; P = 0.049), compared to group II. The relative perimeter of the bone marrow after 45 d did not differ between groups and was 16.49% ± 8.58% for group I, and 15.88% ± 1.73% for group II. Futhermore, after 90 d, in group I the relative perimeter of bone marrow was 1.4 times smaller (12.96 ± 6.99 vs 18.76 ± 7.62; P = 0.049) compared to the relative perimeter of bone marrow in group II.

The use of a highly porous titanium implant, manufactured with 3D printing, for acetabular components provides increased osseointegration compared to a plasma-coated titanium implant.

Revision surgery for complex acetabular defects is still technically challenging. In this study, we discussed and compared the clinical and radiological outcomes of revision surgery between two methods using double-trabecular metal (TM) cups alone or combined with impacting bone grafting (IBG).

The records of 18 patients (18 hips) who underwent revision surgery using double-trabecular metal (double-TM) cups between 2008 and 2016 were retrospectively reviewed. All the patients were diagnosed with Paprosky III acetabular defects. The acetabular defects were reconstructed by double-TM cups alone or in combination with IBG. We used the modified Harris Hip Score (mHHS), University of California, Los Angeles (UCLA), and Short Form 36 (SF-36) to evaluate the clinical outcomes. Pelvis plain X-ray was used to assess hip center of rotation (COR), abduction angle and anteversion angle of acetabular cup, and incorporation of the bone graft to host bone.

The median follow-up time was 61.0 (IQR 56.0 to 65.8) months. No patients underwent re-revision for loosening or any other reasons. Complications included 3 patients (16.7%) with early dislocation and 3 patients (16.7%) with delayed wound healing. The average mHHS and UCLA preoperatively were 44.1 ± 4.0 (range 35 to 50) and 2.6 ± 0.7 (range 2 to 4), respectively and at the last follow-up were 73.7 ± 4.2 (range 68 to 85) and 7.3 ± 0.5 (range 7 to 8), respectively. The mean SF-36 scores at the last follow-up were improved significantly than preoperative scores, especially in bodily pain category (P < 0.05). The average limb-length discrepancy (LLD) decreased significantly from 24.2 ± 2.6 (range 20 to 32) mm preoperatively to 5.8 ± 1.8 (range 3 to 9) mm at the last follow-up, respectively. However, there was no significant difference between two methods at the last follow-up in terms of mHHS, UCLA, SF-36, LLD, and hip COR (P > 0.05). Radiographic evaluation demonstrated bone graft incorporation in all hips in the follow-up.

Defect reconstruction using double-TM cups alone or combined with IBG are practical and reliable treatment options for Paprosky III acetabular defects without pelvic discontinuity. Nevertheless, high postoperative complication rate, especially in terms of dislocation, remains a challenge.

During the last decade, total hip arthroplasty has become a common procedure performed in young patients, as well as elderly ones. This has led to an increase in total hip arthroplasty revisions. Loosening of primary components with associated bone loss represents the major cause of total hip arthroplasty revision. This study evaluates the safety and performance of an enzyme-deantigenic equine-derived bone graft material in acetabular defect reconstruction.

Records of 55 patients who were treated for Paprosky type II or III acetabular bone defects with arthroplasty revisions using equine-derived bone and followed for an average of 34 months (range from 24 to 48 months) were analyzed.

Of the 55 revisions, 49 (89%) were regarded as successful, showing good osteointegration without signs of mobilization. Failures included six cases (11%) of mobilization: five cases of aseptic mobilization (9.1% of revisions, 83% of failures) and one case of septic mobilization (1.9% of revisions, 17% of failures). These results are consistent with those of studies having a similar follow-up period for allografts used in combination with trabecular metal components.

Results of the present study suggest that enzyme-treated equine-derived bone grafts may be a valid alternative to autogenous and homologous bone grafts in total hip arthroplasty revision.

To investigate the clinical, radiological and functional outcomes of acetabular revisions with acetabular reinforcement rings and cages.

A comprehensive literature study of international databases was performed. Inclusion criteria were cementless revisions, use of reinforcement rings, radiological and clinical follow-up, availability of full text in English, publication between January 1990 and July 2018. In a second further analysis, we selected only studies describing patients with more severe acetabular defects (AAOS 3, AAOS 4, Paprosky III). Data extracted included mean follow-up period, radiographic follow-up, functional scores, implant failures and survival rate.

We included in our review 1327 acetabular revisions described in 28 articles. The most commonly used reinforcement rings were Burch-Schneider ring, the Muller ring and the Ganz ring. Mean follow-up for all patients together was 8.8 years. Clinical or radiological signs of loosening were reported in 191 patients, 83 patients needed further acetabular revision for aseptic loosening and 41 patients received additional surgeries for septic loosening. The mean value of the Harris Hip Score reported at the last follow-up was 76.3. Nineteen articles fulfilled the criteria for further analysis about high-grade acetabular bone defects. We analyzed 649 revisions with mean follow-up period of 8.2 years. Clinical or radiological loosening was reported in 90 patients, additional acetabular revision was performed in 39 patients and 25 patients needed further surgeries for deep infection.

Acetabular revisions with cages are characterized by good survival rates and functional scores with a mean follow-up period of 8 years.