Clinical and radiographic assessment of cementless acetabular revision with morsellised allografts

Is Retention of the Acetabular Component at Revision Surgery a Long-Term Solution?

Background

Acetabular retention in revision total hip arthroplasty (THA) may be advantageous, yet long-term survival data is limited. Thus, we investigated long-term survivorship of retained acetabular components in revision THA with analysis of rerevision rate, instability risk, and clinical outcomes.

Methods

We reviewed 98 hips with polyethylene wear and/or osteolysis that were revised with retained acetabular components. Acetabular inclination and anteversion were measured from prerevision radiographs. A retrospective chart review was performed, collecting outcomes of interest including Harris hip score, instability events, and rerevision surgery. Kaplan-Meier analysis was used to calculate the risk of revision over time. Predictors of survival including acetabular component position were analyzed by multiple logistic regression.

Results

Average follow-up was 13 years (range, 5-24). Survivorship rates at 5, 10, 15, and 20 years were 89.7%, 81.6%, 70.8%, and 63.8%, respectively. There was improvement in average Harris hip score (61 to 76, P < .0001). There was a 9% rate of dislocation, and 6 hips (6%) were rerevised for recurrent instability. Overall, there were 23 (23%) rerevisions at an average of 6.1 years with the most common reasons being instability (6%) and aseptic loosening (6%). Use of conventional polyethylene was the only identified independent predictor of rerevision (P = .025).

Conclusions

Retention of a well-fixed acetabular component in revision THA provides acceptable long-term outcomes with a 15-year survivorship of 71%. Instability and aseptic loosening were the most common reasons for rerevision. Surgeons may consider retaining the acetabular component at revision surgery if the implant is well-fixed and well-positioned.

Biphasic bone graft substitute in revision total hip arthroplasty with significant acetabular bone defects : a retrospective analysis

AIMS

Large acetabular bone defects encountered in revision total hip arthroplasty (THA) are challenging to restore. Metal constructs for structural support are combined with bone graft materials for restoration. Autograft is restricted due to limited volume, and allogenic grafts have downsides including cost, availability, and operative processing. Bone graft substitutes (BGS) are an attractive alternative if they can demonstrate positive remodelling. One potential product is a biphasic injectable mixture (Cerament) that combines a fast-resorbing material (calcium sulphate) with the highly osteoconductive material hydroxyapatite. This study reviews the application of this biomaterial in large acetabular defects.

METHODS

We performed a retrospective review at a single institution of patients undergoing revision THA by a single surgeon. We identified 49 consecutive patients with large acetabular defects where the biphasic BGS was applied, with no other products added to the BGS. After placement of metallic acetabular implants, the BGS was injected into the remaining bone defects surrounding the new implants. Patients were followed and monitored for functional outcome scores, implant fixation, radiological graft site remodelling, and revision failures.

RESULTS

Mean follow-up was 39.5 months (36 to 71), with a significant improvement in post-revision function compared to preoperative function. Graft site remodelling was rated radiologically as moderate in 31 hips (63%) and strong in 12 hips (24%). There were no cases of complete graft site dissolution. No acetabular loosening was identified. None of the patients developed clinically significant heterotopic ossification. There were twelve reoperations: six patients developed post-revision infections, three experienced dislocations, two sustained periprosthetic femur fractures, and one subject had femoral component aseptic loosening.

CONCLUSION

Our series reports bone defect restoration with the sole use of a biphasic injectable BGS in the periacetabular region. We did not observe significant graft dissolution. We emphasize that successful graft site remodelling requires meticulous recipient site preparation.Cite this article: Bone Jt Open 2022;3(12):991-997.

Survival Analysis of Allografting and Antiprotrusio Cage in Treating Massive Acetabular Bone Defects

BACKGROUND

Massive acetabular bone defects reconstructed with allografting and antiprotrusio cage in revision hip arthroplasty is less reported in the literature. We here report a series of 84 antiprotrusio cages and analyze the risk factors associated with failure.

METHODS

All instances of use of an antiprotrusio cage for massive acetabular defect (Paprosky type IIc, III, and pelvic discontinuity) between 2002 and 2017 in the authors' institute were reviewed after institutional review board's approval. Survival analyses based on clinical data, bone defect (Paprosky system), type of allograft, size of cage, fixation quality, and position of cage were performed. Failure was defined as cage loosening or breakage, poor hip function, or cage revision for any reason.

RESULTS

A total of 84 cages in 77 patients (mean age, 62.9 years), with a mean follow-up period of 6.2 years, had a survival rate of 82.1%. Failure was noted in 15 hips, including mechanical failure in 8 hips, recurrent dislocation in 1 hip, poor hip function in 1 hip, and periprosthetic joint infection in 5 hips. Pelvic discontinuity, reconstruction with morselized allograft alone, and fewer than 4 fixation points to the host bone were associated with higher failure rates (hazard ratios, 4.02, 3.42, and 9.9, respectively).

CONCLUSION

We found that an antiprotrusio cage combined with strut allografts, fixed securely to the host bone (>4 fixation points), are beneficial for the management of massive acetabular bone defects. However, pelvic discontinuity remains a challenge that warrants the further study of technical or prosthetic innovations, such as triflange implants, cup cage, and 3D-printed implants.

Acetabular Cup Revision Arthroplasty Using Morselized Impaction Allograft

The rate of acetabular cup revision arthroplasty is gradually rising along with an increased risk of osteolysis and prosthesis loosening over time and an increase in life expectancy. The goals of revision total hip arthroplasty are: i) implant stability through reconstruction of large bone defects, ii) restoration of range of motion and biomechanics of the hip joint, and iii) normalization of uneven limb lengths. In acetabular cup revision arthroplasty, stable fixation of acetabular components is difficult in the presence of severe bone loss (e.g., evidence suggests that it is challenging to achieve satisfactory results in cases of Paprosky type 3 or higher bone defects using conventional techniques). The author of this study performed acetabular revision to manage patients with large areas of defective bones by filling in with morselized impaction allografts. These allografts were irradiated frozen-stored femoral heads acquired from a tissue bank, and were applied to areas of an acetabular bone defect followed by insertion of a cementless cup. When this procedure was insufficient to obtain primary fixation, a tri-cortical or structural allograft using a femoral head was carried out. Structural stability and bone incorporation were confirmed via long-term follow-up. This study aims to review conventional surgical techniques and verify the utility of surgical procedures by analyzing the author's surgical methods and discussing case reports.

The use of morselized allografts without impaction and cemented cage support in acetabular revision surgery: a 4- to 9-year follow-up

Background

Acetabular revision arthroplasty with major bone loss is one of the most difficult operations in orthopedic surgery. The goal of the study was to evaluate midterm clinical results of the use of morselized allografts with cemented cage support in revision total hip replacement.

Methods

We identified 28 patients (29 hips) at an average follow-up of 73 months. Harris Hip Scores (HHS) were assessed before and after surgery. Pre- and postoperative radiographs were evaluated for restoration of the center of rotation, component migration, and graft incorporation.

Results and discussion

At follow-up, the mean HHS improved from 34 (range, 20–45) to 80 (range, 71–98) points. None of the components had been re-revised. On average, the revised hip center of rotation was improved significantly. Incorporation of the graft was complete in 23 hips. The midterm result of cage reconstruction with morselized bone allograft is relatively better than other studies using a similar cage construction. We believe we have three special modifications of this reconstruction technique that are beneficial for bone incorporation.

Conclusions

These data confirm that acetabular reconstruction using morselized allografts and cemented acetabular cages is effective in the midterm as a treatment for acetabular loosening with massive bone deficiency.

Revision Total Hip Arthroplasty with Retained Acetabular Component

BACKGROUND

Aseptic loosening and osteolysis commonly limit the survivorship of total hip prostheses. Retention of a well-fixed acetabular component, rather than full acetabular revision, has multiple advantages, but questions have lingered regarding the clinical success and prosthetic survivorship following this procedure. We examined the impact of acetabular component position, polyethylene type, liner insertion technique, femoral head size, and simultaneous revision of the entire femoral component (as opposed to head and liner exchange) or bone-grafting on mid-term to long-term prosthetic survival following such limited revisions.

METHODS

One hundred hips in 100 patients with osteolysis, polyethylene wear, or femoral component loosening underwent revision total hip arthroplasty with retention of the acetabular component. Acetabular component inclination and anteversion were measured on prerevision radiographs and were categorized according to predetermined positional safe zones (inclination of 35° to 55° and anteversion of 5° to 25°). Operative reports were reviewed for femoral head size, polyethylene liner type (conventional or highly cross-linked), liner insertion technique (use of the existing locking mechanism or cementation), whether the patient had revision of the entire femoral component, and use of bone graft. Outcomes of interest included the Harris hip score, University of California at Los Angeles (UCLA) activity score, episodes of instability, and need for repeat revision.

RESULTS

At an average of 6.6 years (range, two to fourteen years) postoperatively, the Harris hip and UCLA activity scores were both significantly improved compared with the preoperative scores (p < 0.0001 and p < 0.01, respectively). Overall, the failure rate was 13%. In addition, 6% of the patients had postoperative instability. Hips in which the acetabular component was outside of the safe zone for inclination had a higher rate of failure (p = 0.048). Use of conventional, rather than highly cross-linked, polyethylene at the time of revision was also associated with an increased rate of repeat revision (p = 0.025).

CONCLUSIONS

Revision total hip arthroplasty with retention of the acetabular component is associated with good outcomes in hips with an appropriately positioned, well-fixed acetabular component. Acetabular components outside the safe zone for inclination were at a higher risk for failure, as was use of conventional polyethylene.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The use of fibre-based demineralised bone matrix in major acetabular reconstruction: surgical technique and preliminary results

Acetabular osteolysis associated with socket loosening is one of the main long-term complications of total hip arthroplasty. In case of major bone loss, where <50% host bone coverage can be obtained with a porous-coated cementless cup, it is generally agreed that a metal ring or cage in association with a cemented component and allograft bone should be used. In order to promote allograft bone consolidation and incorporation, we have associated demineralised bone matrix (DBM, Grafton® A Flex) to the construct ion. Here we describe the technical details of major acetabular reconstruction using the Kerboull acetabular reinforcement device with allograft bone and DBM. This device has a hook that must be placed under the teardrop of the acetabulum and a plate for iliac fixation. The main advantages of this device are help in restoring the normal centre of hip rotation, guiding the reconstruction and partially unloading the graft. The Kerboull acetabular reinforcement device has provided a 92% survival rate free of loosening at 13-year follow-up in a consecutive series of 60 type III and IV deficiencies. Our preliminary results using DBM indicate faster allograft consolidation and remodelling.