Component selection in revision total hip arthroplasty

Standardized 3D-printed trabecular titanium augment and cup for acetabular bone defects in revision hip arthroplasty: a mid-term follow-up study

BACKGROUND

The aim of this study was to assess the feasibility and outcomes of standardized three-dimensional (3D)-printed trabecular titanium (TT) cups and augments to reconstruct most acetabular defects.

METHODS

We included 58 patients with Paprosky type II and III acetabular bone defects who underwent revision hip arthroplasty between 2015 and 2018. Patients who were revised without 3D-printed augments, and cases who were lost to follow-up and died during follow-up were excluded. Radiographic and clinical outcomes were evaluated. A Kaplan-Meier survivorship curve was generated. The mean follow-up was 64.5 (range 49-84) months.

RESULTS

In total, 48 (82.8%) acetabular revisions were performed using standardized 3D-printed TT cups and augments, and a retrospective review was conducted on 43 revisions. The average position of the vertical center of rotation and leg length discrepancy were significantly decreased from 42.4 ± 9.1 mm and 38.4 ± 10.7 mm to 22.8 ± 3.4 mm and 4.1 ± 3.0 mm, respectively. Non-progressive radiolucent lines were observed in 3 (7.5%) acetabular components with no indications for revision. The mean Harris hip score, Oxford hip score and EuroQol five-dimensional questionnaire score increased from 33.0 ± 10.7, 11.4 ± 3.4 and 0.29 ± 0.09 to 80.3 ± 8.8, 35.8 ± 2.4 and 0.71 ± 0.10, respectively. The revision-free survival rate of the acetabular component was 93.0% (40/43), with a rate of revision for aseptic loosening of 2.3% (1/43).

CONCLUSION

Standardized 3D‑printed TT augments and cups could be used to reconstruct the majority of Paprosky type II and III acetabular defects in revision hip arthroplasty and demonstrated encouraging results at mid-term follow-up.

Revision total hip arthroplasty using a fluted, tapered, modular stem follow-up method for a mean of three years: A preliminary study

Objective: This study aimed to evaluate the results and complications related to revision total hip arthroplasty within a short-to-medium follow up period. Methods: From January 2016 to January 2020, we reviewed 31 prosthetic hip arthroplasty stem revisions using a fluted, tapered modular stem with distal fixation. The median age of the patients was 74.55-79 years. The survival rate was 100%, and there were no re-revisions. The Harris hip score improved from an average of 36.5 ± 7.8 before surgery to 81.8 ± 6.2 at the final follow-up. Results: The average final follow-up was 36 (24-60) months. During this time, there was no periprosthetic infection, no prosthesis loosening or breakage, and no sciatic nerve injury. Complications included four (12.9%) intraoperative fractures and eight (25.8%) dislocations that had no stem fractures. The postoperative limb was lengthened by 17.8 ± 9.8 mm. In most cases, bone regeneration was an early and important finding. Three cases underwent extended trochanteric osteotomy, and bone healing was achieved by the final follow-up. Conclusion: The modular tapered stem reviewed in this study was very versatile, could be used in most femoral revision cases, and allowed for rapid bone reconstruction. However, a long-term follow-up study is needed to confirm these results.

Case report: Three-dimensionally printed patient-specific acetabular cage for revision surgery of aseptic loosening in a dog with micro total hip replacement

A 2-year-old castrated male Pomeranian dog was presented for regular follow-up after micro total hip replacement (mTHR) 16 months prior to presentation. Clinically, the dog did not show any noticeable lameness of the left hindlimb, except for external rotation during walking. However, radiographic findings, namely rotation and medialization of the acetabular cup with a periprosthetic lucent line and bone formation medial to the acetabulum, were interpreted as aseptic loosening of the acetabular component. Because the dog was incompatible with the conventional THR revision method owing to severe bone defects in the acetabulum, a patient-specific titanium acetabular cage prosthesis with biflanges and four cranial and one caudal screw hole was designed for revision surgery. A custom-made acetabular cage was prepared, and it had a 12-mm polyethylene cup fixed with polymethylmethacrylate bone cement and positioned in the acetabulum. After the custom-made acetabular cage was anchored to the pelvic bone with the five cortical screws, reduction of the prostheses was achieved smoothly. The dog showed almost normal limb function without external rotation of the left hindlimb 2 weeks postoperatively. Bone remodeling and stable implant position were noted on radiographic images 3 years after revision surgery, with no evidence of loosening. Based on the clinical outcomes, the use of a custom-made acetabular prosthesis can be an effective treatment option for revision arthroplasty in acetabula with severe bone loss and structural changes in small-breed dogs.

Influence of dual-mobility acetabular implants on revision and survivorship of cup and Kerboull-type reinforcement ring constructs in aseptic acetabular loosening

INTRODUCTION

Dual-mobility (DM) acetabular implants have been used in revision total hip arthroplasty (THA) to prevent postoperative instability, with excellent mid-term survivorship. However, few comparative studies assessed the long-term outcomes of DM implants used in Kerboull-type reinforcement ring constructs for acetabular revision. The present study aimed to compare long-term survivorship, dislocation rates and clinical outcome between DM acetabular implants and conventional single-bearing (SB) implants when cemented in a reinforcement ring.

HYPOTHESIS

Dual-mobility implants are associated with equivalent survivorship and lower dislocation rates than SB implants.

MATERIAL AND METHODS

A retrospective study included 60 revision THAs for aseptic loosening using a Kerboull-type reinforcement ring, and finally included 2 groups of 23 patients with either DM or SB cemented acetabular implants after matching for age, gender, BMI and preoperative Harris hip score. Mean follow-up was 10 years (range, 6-14 years). Acetabular implant survivorship, dislocation rate and radiographic failure incidence (>5mm migration, progressive radiolucency, graft non-integration, reinforcement ring breakage) were compared between the two groups. Clinical outcomes used the Harris hip score, the Postel-Merle d'Aubigné score and the Parker score.

RESULTS

Survivorship free of aseptic acetabular re-revision was 89% at 10 years, with no significant difference between DM and SB (91% and 86%, respectively; p=0.54). Single-bearing implants showed a hazard ratio for dislocation of 6.7 (95% CI, 1.5-29.6; p=0.01) compared to DM implants. There were no significant differences in radiologic failure (10-year survivorship 72% and 64%, respectively; p=0.88) or functional scores.

DISCUSSION

The present study confirmed the impact of dual-mobility implants in reducing long-term dislocation risk when used in Kerboull-type reinforcement ring constructs for acetabular aseptic revision, with no increased risk of re-revision compared to conventional single-bearing implants.

LEVEL OF EVIDENCE

III, comparative retrospective study.

A novel revision system for complex pelvic defects utilizing 3D-printed custom prosthesis

Background

Thus far, the hip revision surgery has been widely used and promoted, and the technology has been constantly innovated, such as tissue engineering, 3D printing prosthesis, etc. However, traditional standardized prosthesis, allograft, autograft, bone cement and reinforcing ring are still the main treatment methods in the mainstream pelvic defects classification systems for hip revision. In addition, the mainstream classification systems are still mainly focus on the peri-acetabulum, but less on the large-scale complex pelvic defects that widely affecting the regions far away from the acetabulum, which also have a significant impact on the holistic biomechanical properties of pelvis.

Methods

After integrating the design experience of custom prostheses and the understanding of biomechanical properties of pelvis, an innovative pelvic defects classification for custom revision was preliminarily proposed, and was practiced in surgeries. Some typical cases were chosen for elucidation in this study, and two observers each evaluated their CT data independently twice. Intraobserver and interobserver agreement were calculated using the kappa statistic to evaluate the reliability. The pelvis defects were classified into five types and two subtypes. The corresponding reconstruction principles, as the main basis to support the classification, were also described in detail. Prosthesis position examination and Harris hip score were utilized to evaluate the clinical outcome.

Results

The installed prostheses resulted in high concordance with preoperative position planning, significantly improved Harris score, low postoperative complication rate and no re-revision case. In addition, The interobserver and intraobserver agreement were both excellent.

Conclusion

The presenting revision system for complex pelvic defects utilizing 3D-printed custom prosthesis and corresponding classification of pelvic defects can preliminarily guide patients’ grouping and prosthesis design, and may potentially provide an innovative, feasible, and efficient basis for complex total hip arthroplasty (THA) revision.

Translational potential statement

This study provides a novel method for prosthetic revision of peri-acetabular pelvic defects, and is expected to systematically improve the efficiency of prosthesis design and surgery in clinical practice.

Modular or Monolithic Tapered Fluted Prostheses for Periprosthetic Fractures: Which One Could Work for You?

Periprosthetic fracture around a femoral component is a potentially devastating complication after total hip arthroplasty. Surgical treatment is often technically demanding and requires a thorough understanding of fracture care and revision joint reconstruction. Advancements in femoral component designs for revision total hip arthroplasty have improved management of this challenging complication. It is important for surgeons to understand which femoral component design might best suit their needs. We present an overview of revision total hip arthroplasty in the setting of periprosthetic fracture, focusing on comparing the 2 most popular femoral component revision models, the modular and monolithic tapered fluted conical prostheses.

Trabecular Metal Augments for Severe Acetabular Defects in Revision Hip Arthroplasty: A Long-Term Follow-Up

BACKGROUND

Paprosky type IIIa and IIIb acetabular defects remain technically challenging during revision hip arthroplasty. Numerous surgical options exist to counter extensive acetabular bone loss with high postoperative complication and revision rates reported. Our aim was to report comprehensive long-term outcomes of our experience with Trabecular Metal (TM) augments for these difficult cases.

METHODS

38 patients underwent revision total hip arthroplasty at our institution from 2009 to 2014 where a TM augment was used for acetabular deficiency. Prospective radiographic and Patient-Reported Outcome Measures were recorded and analyzed to a mean of 7.3 years (range: 5.4 to 10.8).

RESULTS

No patient was excluded or lost to follow-up. Complications included 3 intraoperative fractures, 1 early infection requiring washout with implant retention, 1 early revision due to allograft resorption, and 6 patients who required late repeat revision surgery: 3 for late infection, 2 for aseptic loosening with augment fracture or dislocation, and 1 for recurrent dislocation. The estimated mean implant survivorship was 8.99 years. 93.5% of augments remaining were well osseointegrated while 97% of the acetabular shells were osseointegrated. Hip center of rotation was restored by a mean of 14 mm inferiorly without significant medialization. Short Form-12 (SF-12) and Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores were significantly reduced postoperatively to a level comparable to the average individual.

CONCLUSION

This long-term study details our experience of TM augments for the most severe acetabular defects. For such cases, no excellent surgical solution exists; in comparison to alternative methods, we advocate that this technique is reasonably safe and effective.

Salvage of Failed Femoral Neck Fracture Fixation with Conversion Total Hip Arthroplasty Using the Direct Anterior Approach

Purpose

Failed femoral neck fracture (FNF) fixation with in situ pinning presents a surgical challenge. Osteoporotic bone, retained hardware, and a typically elderly population magnify the risks of surgery. Here, outcomes of conversion total hip arthroplasty (THA) using two separate incisions in these high-risk patients were examined.

Materials and Methods

Medical records for 42 patients with a prior history of FNF fixation who underwent conversion THA with hardware removal between 2009 and 2019 were retrospectively reviewed. Surgery was performed by a single surgeon at a single institution. All patients underwent hardware removal followed by direct anterior approach (DAA) THA using two separate incisions. Clinical outcomes, radiographic findings, and perioperative morbidity and mortality are reported.

Results

Clinically, there were no postoperative dislocations, periprosthetic fractures, or infections at follow-up. After a mean follow-up of 4 years, the mean hip disability and osteoarthritis outcome score, junior (HOOS, Jr) was 91. Radiographically, the mean postoperative cup abduction was 44 degrees and the mean cup anteversion was 21 degrees with an improvement in preoperative leg length discrepancy. Perioperative complications included one case of immediate foot drop and two readmissions for medical issues. One patient died one month after conversion THA.

Conclusion

Salvage of failed FNF treatment may be managed with conversion THA and DAA with a separate incision for hardware removal. Preservation of posterior soft tissues using a DAA and intraoperative fluoroscopy may mitigate well-known complications related to fracture and dislocation. While favorable clinical outcomes are possible, salvage surgery is still not without substantial surgical and medical risks.

Custom acetabular prosthesis for total hip replacement: A case report in a dog with acetabular bone loss after femoral head and neck ostectomy

OBJECTIVE

To describe the application of a custom acetabular prosthesis (CAP) for total hip replacement (THR) in a dog 20 months after femoral head and neck ostectomy (FHNO).

STUDY DESIGN

Case report.

ANIMAL

A 10-year-old, male, castrated, Labrador retriever with progressive lameness and pain after FHNO.

METHODS

Acetabular bone stock was assessed as insufficient for conventional THR, so a biflanged CAP was designed and three-dimensionally printed in titanium to bridge the bone defect. The CAP had a porous surface for long-term biologic fixation on the backside and was anchored to the ilium and ischium with screws. A polyethylene cup was cemented into the CAP, and a bolted cementless femoral stem was inserted.

RESULTS

The loss of the conventional anatomic landmarks complicated intraoperative orientation and led to eccentric reaming and 5-mm malalignment of the CAP. Reduction of the prosthetic joint was difficult because of periarticular fibrosis, loss of functional muscle length, and thickness of the CAP, and intraoperative shortening of the stem neck was required. Postoperative complications included sciatic neurapraxia, which resolved with time and conservative management. Absence of pain and improvement of range of motion were observed at clinical examination 12 months after surgery; however, moderate hind limb lameness persisted due to muscle tension. No evidence of implant loosening was noted on radiographs acquired 24 months after surgery.

CONCLUSION

Femoral head and neck ostectomy with poor functional outcome was ameliorated by using a CAP in this dog.

CLINICAL SIGNIFICANCE

Use of a CAP can be considered to treat acetabular defects in dogs.

The biological acetabular reconstruction with bone allografts in hip revision arthroplasty

BACKGROUND

Reconstructions in case of acetabular bone loss in hip revision arthroplasty are challenging. A few techniques have been proposed, with inconstant outcomes. Biological reconstructions using bone allografts may address the acetabular bone loss and restore the hip anatomy. Aim of this work was the description of the surgical technique and the evaluation of the outcomes using a regional arthroplasty register.

MATERIALS AND METHODS

Minor or massive bone allografting was performed in hip revision arthroplasties in a tertiary center. Bulk allografts were used in severe acetabular bone losses. Fresh-frozen femoral heads were impacted in the bone cavity and porous cups were implanted; multihole sockets were used when necessary. In DeLee A zone, no grafts were used in order to reduce overstress graft resorption. The results were evaluated using a regional arthroplasty register, and a comparison with revisions without bone grafts was performed investigating re-revision rates and reasons for further revisions.

RESULTS

At 10 years, acetabular revisions with bone allografts achieved a similar survival rate than revisions without bone grafts. The re-revisions occurred more frequently in revisions without bone allografts (10.8 vs. 9.7%). In the allograft cohort, septic loosening was lower (0.3 vs. 2.6%), whereas a higher rate of aseptic cup loosening was experienced (2.7 vs. 1.4%).

CONCLUSIONS

Bone allografts may provide a good restoration of the acetabular bone stock and the hip biomechanics. Septic loosening does not seems a major concern, whereas a higher rate of aseptic cup loosening should be expected when bone grafts are used.

Acetabular Revision Using Trabecular Metal Augments for Paprosky Type 3 Defects

BACKGROUND

Trabecular Metal (TM) augments are one option when reconstructing bone loss during acetabular side revision surgery.

METHODS

We studied 38 consecutive patients with Paprosky type 3 defects that were revised using a TM shell and one or more augments over a 6-year period. There were 29 Paprosky type 3A defects and 9 Paprosky type 3B defects. The mean age of the patients at the time of surgery was 68.2 years (range 48-84). The mean length of follow-up was 36 months (range 18-74).

RESULTS

The mean preoperative short form 12 health survey improved from 27.7 before operation to 30.1 at the time of final follow-up (P = .001). The mean Western Ontario and McMaster Universities Osteoarthritis Index score improved from 53 preoperatively to a mean of 78.8 at final follow-up (P < .0001). There was evidence of radiographic loosening in 7 of the cup-augment constructs. One patient developed a deep infection requiring re-revision. Two patients required revision for aseptic loosening.

CONCLUSION

The use of TM in complex acetabular reconstruction is associated with good outcome in the short to medium term.

The use of customized cages in revision total hip arthroplasty for Paprosky type III acetabular bone defects

PURPOSE

Revision total hip arthroplasty (THA) is challenging if severe periacetabular bone loss is present. Here we describe a method that uses a customised cage to reconstruct an acetabulum with a massive bone defect.

METHODS

Designed with the aid of the rapid prototyping technique, a customised cage with a hook, crest and flange or braids was made, and then utilized to reconstruct severe compromised acetabulum in revision THA since 2001. Twenty-two patients (23 hips) were included in this study. The mean patient age at the time of surgery was 60.9 years (range, 38-80 years). Three hips had massive acetabular bone defects of Paprosky type IIIA and 20 of type IIIB. The Harris hip score was used to evaluate hip function. Radiographs were taken to evaluate loosening of the cage and resorption of allograft bone.

RESULTS

The average follow up was 81.6 ± 24.9 months. The mean Harris hip score improved from 39.6 pre-operatively to 80.9 at the final follow-up. There were no instances of deep infection, severe venous thrombosis, and nerve palsy. One patient who had an intra-operative rupture of the superior acetabular artery was successfully treated using the haemostatic suturing technique. Two patients experienced dislocation at post-operative days four and six, respectively, and both were treated with closed reduction and skin traction for three weeks.

CONCLUSIONS

The present study demonstrates that a customised cage may be a promising option for THA revision of severely compromised acetabula. Extended follow-up is necessary to evaluate the long-term performance of this approach.