Long-term results of the uncemented acetabular component in a primary total hip arthroplasty performed for protrusio acetabuli: a fifteen year median follow-up

Long-Term Outcomes of Primary Cemented Total Hip Arthroplasty with Acetabular Bone Graft for Protrusio Acetabuli: Minimum 10-Year Follow-Up

Background: This study reports the long-term survivorship of primary total hip arthroplasty (THA) for protrusio acetabuli. Methods: Patients undergoing THA utilising cement and bone graft acetabular reconstruction for protrusio acetabuli in a university teaching hospital during the period 2003 to 2014 were included. Kaplan-Meier survival estimates were calculated with 95% confidence intervals (CI) up to 15 years following surgery. PROMs were collected pre- and post-operatively for hip-specific function (Oxford Hip Score [OHS]) and health-related quality of life (HRQoL) using the EQ-5D-3L. Results: 129 consecutive THAs (96 patients) performed for protrusio acetabuli were identified (median age 69, IQR 61-75; female 115 [89.1%]; 38 [29.5%] inflammatory arthritis) with a mean follow-up of 15.7 years (range: 10.1-20.1 years). At the final follow-up, fifty-six (43.4%) patients had died and there were eleven (8.5%) reoperations, of which eight (6.2%) involved the revision of the acetabular component. The fifteen-year Kaplan-Meier any-reoperation survival estimate was 91.3% (95% CI 85.9-97.0). When considering all-cause acetabular revision only, the 15-year survival estimate was 93.1% (95% CI 88.2-98.3). The median pre-operative OHS improved significantly from baseline to 1 year post-THA, beyond the minimal important change (mean difference 28, 95% CI 25-30, p < 0.001). Similarly, there were clinically relevant improvements in HRQoL at 1 year post surgery (mean difference 0.10, 95% CI 0.06-0.15, p < 0.001). Conclusions: This study demonstrates that primary cemented THA utilising acetabular bone graft for reconstruction in patients with protrusio acetabuli was associated with 15-year survival rates of 93.1% and clinically relevant improvements in hip-specific function and HRQoL.

Functional Outcome after Direct Anterior Approach Total Hip Arthroplasty (DAA-THA) for Coxa Profunda and Protrusio Acetabuli-A Retrospective Study

Objective: The direct anterior approach (DAA) is a recognized technique for total hip arthroplasty (THA) that spares soft tissue. Functional and clinical outcomes following THA via the DAA in patients with complex acetabular deformities, specifically coxa profunda (CP) and protrusio acetabuli (PA), have yet to be determined. Methods: A retrospective analysis was conducted on 188 primary THA cases, including 100 CP hips and 88 PA hips, performed via the DAA. Functional and clinical outcomes were evaluated by means of the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and Harris Hip Score (HHS) preoperatively and at a mean follow-up of 46 ± 14 months. Furthermore, potential complications were assessed. Results: From the preoperative to the latest postoperative visit, a significant improvement in the WOMAC total score was observed (CP: -34.89 ± 20.66; PA: -40.38 ± 21.11). The length of stay (LOS) was the only parameter predictive of the postoperative WOMAC total score, with each day of LOS increasing the postoperative WOMAC by a mean of 1.77 points (p < 0.01). The HHS improved by 38.37 ± 14.23 (PA-group) and 32.79 ± 14.89 points (CP-group). No significant difference in the patient-reported outcome measures (PROMs) between the CP- and PA-group was found. The survival rate for any revision was 97.70% (PA-group) and 92.80% (CP-group). Conclusion: The results of this study indicate that the minimally invasive DAA was not predictive of the functional and clinical outcome following DAA-THA in patients with CP and PA. Improvements in the mean WOMAC and HHS scores were above or within the reported MCID. Additionally, revision rates were well below those reported in the literature for short and intermediate follow-up periods.

Total Hip Arthroplasty in Protrusio Acetabuli: A Systematic Review

Protrusio acetabuli, or abnormal protrusion of the femoral head into the acetabulum, requires performance of a total hip arthroplasty (THA) for which various reconstruction techniques and outcomes have been described. The aim of this systematic review is to provide a comprehensive analysis of the current evidence, evaluate treatment efficacy, compare surgical techniques, and identify topics for future research along with improving evidence-based decision-making, improving patient outcomes in the management of this condition. A thorough systematic review of the PubMed, Embase, Cochrane Library databases, and Scopus library was conducted, and articles describing techniques of THA for treatment of protrusion acetabuli were extracted. The initial search generated 751 results. After exclusion, 18 articles were included. Of these, eight were prospective studies and 10 were retrospective. Surgery was performed on 783 hips with a mean age of 60 years; 80% of females who mostly had inflammatory arthritis were followed up for 8.86 years (range, 2-15.4 years). Good outcomes have been achieved with THA using uncemented cups with bone graft; however, no conclusion could be drawn with regard to the femoral side. It can be concluded that the concept of restoration of the anatomical hip center of rotation is paramount for good outcome and better survival of the implant is important when using uncemented cups with a bone graft. In addition, screw augmentation for fixation is not recommended unless absolutely necessary. The most common complications were aseptic loosening and heterotopic ossification. While the former required revision, conservative management was administered for the latter.

Is Restoration of Hip Center Mandatory for Total Hip Arthroplasty of Protrusio Acetabuli?

Purpose

While initial fixation using a press-fit of the acetabular cup is critical for the durability of the component, restoration of the hip center is regarded as an attributable factor for implant survival and successful outcome. In protrusio acetabuli (PA), obtaining both restoration of the hip center and the press-fit of the acetabular cup simultaneously might be difficult during total hip arthroplasty (THA). We tested the hypothesis that use of a medialized cup, if press-fitted, will not result in compromise of the implant stability and outcome after cementless THA of PA.

Materials and Methods

A total of 26 cementless THAs of 22 patients with PA were reviewed. During THA, press-fit of the cup was prioritized rather than hip center restoration. A press-fit was obtained in 24 hips. A press-fit could not be obtained in the two remaining hips; therefore, reinforcement acetabular components were used. Restoration of the hip center was achieved in 17 cups; 15 primary cups and two reinforcement components; it was medialized in nine cups. Implant stability and modified Harris hip score (mHHS) between the two groups were compared at a mean follow-up of 5.1 years (range, 2-16 years).

Results

Twenty-six cups; 17 restored cups and nine medialized press-fitted cups, remained stable at the latest follow-up. A similar final mHHS was observed between the restored group and the medialized group (83.6±12.1 vs 83.8±10.4, P=0.786).

Conclusion

Implant stability and favorable results were obtained by press-fitted cups, irrespective of hip center restoration. THA in PA patients showed promising clinical and radiological results.

Partial resection of the posterior wall for hip dislocation in severe acetabular protrusio: a useful surgical option

Aims

In elderly patients with osteoarthritis and protrusio who require arthroplasty, dislocation of the hip is difficult due to migration of the femoral head. Traditionally, neck osteotomy is performed in situ, so this is not always achieved. Therefore, the purpose of this study is to describe a partial resection of the posterior wall in severe protrusio.

Methods

This is a descriptive observational study, which describes the surgical technique of the partial resection of the posterior wall during hip arthroplasty in patients with severe acetabular protrusio operated on between January 2007 and February 2017.

Results

In all, 49 hip arthroplasties were performed. The average age of patients was 60 years, and idiopathic was the most frequent aetiology of protrusio. All patients were treated with femoral head autograft and no intra- or postoperative complications were reported. No patients required revision surgery.

Conclusion

Partial resection of the posterior wall demonstrated to be a safe surgical technique with 100% survival in a follow-up to ten years in total hip arthroplasty due to severe acetabular protrusio.

Cite this article: Bone Joint Open 2020;1-7:431–437.

Arthrokatadysis from post-injection gluteal muscular fibrosis case report

Background

Gluteal muscle contracture (GMC) is a clinical syndrome characterized by the contracture of gluteal muscles, iliotibial band (ITB), and related fascia. GMC is much more prevalent in China, which has been proven to be associated with repeated intramuscular injections into the buttocks and the subsequent fibrosis and contracture.Generally, GMC is manifested mild. Here, we reported a severe case with arthrokatadysis.

Case presentations

A 25-year old man received multiple intramuscular injections of penicillin in the buttock when he was diagnosed with acute tonsillitis at 6 years old. Since then, he was injected penicillin regularly in local hospital because of the repeated acute tonsillitis until he was in high school. When the patient was found by the physical education teacher to be running in a state of external rotation of both feet, he was suggested to go to the hospital for treatment and was initially diagnosed to have GMC. He complained of occasional pain and limited range of motion in the hip joints. X-ray showed a typical arthrokatadysis. After arthroscopic release of GMC, the patient recovered well.

Conclusions

This is possibly the first reported case of arthrokatadysis that was caused by GMC after repeated intramuscular injections into the buttocks. Although the patient recovered well by arthroscopic surgical release of bilateral gluteus maximus contractures, GMC should be paid more attention and treated as early as possible.

Outcomes of Total Hip Arthroplasty in Patients With Acetabular Protrusio

Background:

Acetabular protrusio (AP) is associated with distorted anatomic landmarks and insufficient bone stock that increases complexity of total hip arthroplasty (THA). This study used a large national database to compare outcomes after THA in patients with and without AP.

Methods:

The Nationwide Readmissions Database was used to identify patients with and without AP who underwent THA from 2010 to 2014. Primary outcomes analyzed included complications during index hospitalization and within 90 days of THA.

Results:

Propensity score matching generated 4,395 patients without AP and 4,603 patients with AP. Patients with AP were older (68.1 versus 65.2 years, P < 0.0001), more predominantly women (82.1% versus 55.9%), and had more medical comorbidities as measured by the Elixhauser Comorbidity Index (2.29 versus 1.89, P < 0.0001). Patients with AP had an increased risk of requiring bone graft (odds ratio [OR] = 47.97, 95% confidence interval [CI]: 14.27 to 161.22), receiving a blood transfusion (OR = 1.90, 95% CI: 1.57 to 2.29), and suffering a periprosthetic fracture (OR = 2.56, 95% CI: 1.10 to 5.97) within 90 days of THA. Length and cost of index hospitalization were greater for patients with AP (5.0 versus 4.3 days, P = 0.002; $19,211.88 versus $27,736.30, P < 0.0001).

Conclusion:

Given the current emphasis on hospital cost optimization, it is important to ensure that patients with AP are managed appropriately. Attention should be placed on comprehensive preoperative planning and postoperative monitoring in this population.

Biological and osseointegration capabilities of hierarchically (meso-/micro-/nano-scale) roughened zirconia

PURPOSE

Zirconia is a potential alternative to titanium for dental and orthopedic implants. Here we report the biological and bone integration capabilities of a new zirconia surface with distinct morphology at the meso-, micro-, and nano-scales.

METHODS

Machine-smooth and roughened zirconia disks were prepared from yttria-stabilized tetragonal zirconia polycrystal (Y-TZP), with rough zirconia created by solid-state laser sculpting. Morphology of the surfaces was analyzed by three-dimensional imaging and profiling. Rat femur-derived bone marrow cells were cultured on zirconia disks. Zirconia implants were placed in rat femurs and the strength of osseointegration was evaluated by biomechanical push-in test.

RESULTS

The rough zirconia surface was characterized by meso-scale (50 µm wide, 6-8 µm deep) grooves, micro-scale (1-10 µm wide, 0.1-3 µm deep) valleys, and nano-scale (10-400 nm wide, 10-300 nm high) nodules, whereas the machined surface was flat and uniform. The average roughness (Ra) of rough zirconia was five times greater than that of machined zirconia. The expression of bone-related genes such as collagen I, osteopontin, osteocalcin, and BMP-2 was 7-25 times upregulated in osteoblasts on rough zirconia at the early stage of culture. The number of attached cells and rate of proliferation were similar between machined and rough zirconia. The strength of osseointegration for rough zirconia was twice that of machined zirconia at weeks two and four of healing, with evidence of mineralized tissue persisting around rough zirconia implants as visualized by electron microscopy and elemental analysis.

CONCLUSION

This unique meso-/micro-/nano-scale rough zirconia showed a remarkable increase in osseointegration compared to machine-smooth zirconia associated with accelerated differentiation of osteoblasts. Cell attachment and proliferation were not compromised on rough zirconia unlike on rough titanium. This is the first report introducing a rough zirconia surface with distinct hierarchical morphology and providing an effective strategy to improve and develop zirconia implants.

Finite element model of the impaction of a press-fitted acetabular cup

Press-fit surgical procedures aim at providing primary stability to acetabular cup (AC) implants. Impact analysis constitutes a powerful approach to retrieve the AC implant insertion properties. The aim of this numerical study was to investigate the dynamic interaction occurring between the hammer, the ancillary and bone tissue during the impact and to assess the potential of impact analysis to retrieve AC implant insertion conditions. A dynamic two-dimensional axisymmetric model was developed to simulate the impaction of the AC implant into bone tissue assuming friction at the bone-implant interface and large deformations. Different values of interference fit (from 0.5 to 2 mm) and impact velocities (from 1 to 2 m.s^-1) were considered. For each configuration, the variation of the force applied between the hammer and the ancillary was analyzed and an indicator I was determined based on the impact momentum of the signal. The simulated results are compared to the experiments. The value of the polar gap decreases with the impact velocity and increases with the interference fit. The bone-implant contact area was significantly correlated with the resonance frequency (R ² = 0.94) and the indicator (R ² = 0.95). The results show the potential of impact analyses to retrieve the bone-implant contact properties.

Loss to follow-up in orthopaedic clinical trials: a systematic review

PURPOSE

The rate of patients lost to follow-up may contribute to bias in randomized controlled trials (RCTs).

METHODS

We systematically reviewed orthopaedic RCTs from 2008 to 2011, including 559 RCTs with 131,836 enrolled subjects. The loss to follow-up rates and minimum follow-up times were recorded for each trial. Orthopaedic subspecialty, country of origin, number of enrolled patients, patient age, follow-up strategy, and funding type were also recorded.

RESULTS

Loss to follow-up was not reported in 111 of these studies (20 %). Mean loss to follow-up was 10.4 %. No orthopaedic subspecialty demonstrated significantly different follow-up rates. Remote follow-up strategies did not reduce the loss to follow-up rate. Studies with a minimum follow-up length of three years showed significantly higher loss to follow-up rates compared with studies with shorter minimum follow-up time (14.8 % versus 9.8 %, p = 0.01). Studies performed in the United States had a significantly higher rate of loss to follow-up compared with non-United States studies (13.8 % versus 9.4 %; p = 0.01).

CONCLUSIONS

Loss to follow-up rates in published orthopaedic randomized controlled trials is overall relatively low. A substantial portion of publications does not adequately report follow-up data. Studies performed in the United States and studies with longer follow-up periods seem to be at higher risk for loss to follow-up.

Acetabuloplasty with bone grafting in uncemented hip replacement for protrusion

PURPOSE

This retrospective study investigated midterm outcomes of uncemented total hip replacement with acetabuloplasty using impacted bone grafts in acetabular protrusion or primary hip arthritis with an inadequate thickness of the medial acetabular wall.

METHODS

The medial acetabular wall was augmented by impaction bone grafting, and an uncemented cup was implanted in all cases. Hip centre of rotation, medial acetabular wall thickness and cup positioning were evaluated radiologically, with the Harris Hip Score determined at each follow-up.

RESULTS

A total of 32 patients (39 hips) were followed for a mean of 4.5 years, with significant improvement of the Harris Hip Score at the last follow-up. Hip centre of rotation was restored close to the optimal position. Medial acetabular wall thickness and cup position obtained immediately postoperatively were maintained up to the last follow-up, without statistically significant differences. Bone graft integration was observed in all cases by one or two years postoperatively, with no signs of loosening or cup migration at the last follow-up. Heterotopic ossification was identified in 15.4% of cases, without clinical evidence of hip mobility impairment or pain.

CONCLUSIONS

Impaction bone grafting for acetabuloplasty, associated with the implantation of an uncemented cup, yields good midterm results in patients with acetabular protrusion and with primary hip arthrosis with a thinned medial acetabular wall. The restored bone stock and medial acetabular wall thickness enable the placement of the hip centre of rotation close to the optimal location, which could offer further long-term benefits.