Clinical results, radiological findings and survival of a proximally hydroxyapatite-coated hip ABG II stem at a minimum of ten years' follow-up: results of a consecutive multicentre study of 1148 hips in 1053 patients

A high risk of postoperative periprosthetic femoral fracture in Dorr type C femurs: a retrospective cohort study with 10-year follow-up data and a preliminary monochromatic image analysis

BACKGROUND

The authors applied Anatomique Benoist Girard II (ABG II) stems for total hip arthroplasty in some Dorr type C femurs as early attempts. Here, the authors compared the long-term follow-up results between ABG II stems and the 'well-performing' Corail stems and their monochromatic images.

METHODS

Among 3214 primary total hip arthroplasty records, 43 short ABG II stems and 67 standard-length Corail stems implanted in Dorr type C femurs were eligible and enrolled in this retrospective cohort study, with a mean follow-up of 10.3 years. Revision rates, Harris hip scores, and radiologic signs were compared. Spectral CT scans from a representative sample were obtained, and monochromatic images were reconstructed. A quantitative method was developed to measure the volume of the gap around stems. Patient-specific finite element analysis was conducted to investigate the strains.

RESULTS

The revision rate of ABG II stems was significantly higher than that of Corail stems (21 vs. 3%, P <0.05). In the monochromatic images, fewer spot-weld signs (2.2 vs. 3.4, P <0.05) and wider gaps around stems (1.64 cm 3 vs. 0.13 cm 3 , P <0.05) were observed on average in the ABG II group. The mean maximum principal strains of the proximal femurs in the ABG II group were close to the yield strains and significantly larger than those in the Corail group (0.0052 vs. 0.0011, P <0.05).

CONCLUSIONS

There was a high risk of postoperative periprosthetic femoral fracture for ABG II stems in Dorr type C femurs. Monochromatic images provided some insight into the failure mechanism.

LEVEL OF EVIDENCE

III.

Varus stem positioning does not affect long-term functional outcome in cementless anatomical total hip arthroplasty

INTRODUCTION

Varus positioning is the most common femoral malposition in total hip arthroplasty (THA). We compared the long-term outcomes of an anatomical cementless femoral stem positioned in varus versus neutral alignment.

MATERIALS AND METHODS

Data were retrospectively reviewed for all patients receiving a cementless anatomical femoral stem in THA for osteoarthritis between 1998 and 2008. Exclusion criteria were complex cases, incomplete data or follow-up < 1 year. Primary outcome was survival rate with complications and secondary outcomes were clinical scores, thigh pain, radiological score, cortical hypertrophy and filling rate.

RESULTS

Of the 283 included patients, 127 stems were classified as varus and 156 neutral. Mean follow-up was 10 years. Femoral stem size was smaller in the varus group (4.1 vs. 4.4, p = 0.047). A stem-filling rate < 80% was more frequent in the varus group (p < 0.001). The long-term survival rate without any revision procedure was 94.8% ± 2.3% (95%CI 88.4-98.7) in the varus group and 94.1% ± 2.0% (95%CI 91.3-99.1) in the neutral group (p = 0.55). There was no difference in clinical scores, thigh pain or complication occurrence between groups. The Engh-Massin score was lower in the varus group (p < 0.01) and cortical hypertrophy was higher (p < 0.001).

CONCLUSIONS

A varus alignment of a cementless anatomic femoral stem does not affect survivorship, clinical outcomes or complication rate on an average follow-up of 10 years, despite increasing stress-shielding rates.

Higher femoral anteversion restoration accuracy after total hip arthroplasty with a proximally fixed anatomic stem than with a generic straight double-tapered stem

BACKGROUND

Femoral antetorsion in uncemented hip replacement hardly can be modified and the restoration of the anatomic anteversion might be difficult with standard stems. We compared femoral anteversion restoration of a generic straight stem with a proximally fixed anatomic stem that included a dual sagittal curvature and a proximal torsion. It was hypothesised that the restoration of the anteversion was more accurate with the anatomic stem.

PATIENTS AND METHODS

In this comparative study data were collected prospectively of 80 consecutive patients with total hip arthroplasty for primary osteoarthritis. In the first 40 patients (Group I) a cementless proximally fixed anatomic stem with 15° antetorsion of the shaft and a dual sagittal curvature was used. Its design was based on a database of 3D CT images of 600 hips. For comparison a cementless generic straight double-tapered stem was implanted in the next 40 patients (Group II). All operations were performed by one experienced surgeon. All patients had a preoperative 3D planning. A low-dose CT scan was performed at 3 months postoperatively to determine the postoperative stem anteversion.

RESULTS

The demographics were similar in both groups. In group I the mean postoperative femoral anteversion was similar to the preoperative one (22.1° ± 10.2° vs. 20.4° ± 9°; p = 0.2). In Group II, the mean postoperative femoral anteversion was lower (12.9° ± 10.8°, vs. 18.3° ± 12°; p = 0.02).

CONCLUSIONS

Uncemented standard femoral stems tend to reduce femoral anteversion. The used anatomic stem restored femoral anteversion better. The clinical impact of this finding has to be proven.

Periprosthetic fracture as a late mode of failure of the Anatomique Benoist Girard II femoral prosthesis

Aim

The Anatomique Benoist Girard (ABG) II femoral implant was a commonly used stem for primary total hip replacement (THR) at our institution (Launceston, Tasmania Australia). We identified peri‐prosthetic fracture as the main cause of late failure.

Methods

The late periprosthetic fracture rate for ABG II implants was reviewed with national statistics, using Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) data. National revision rates for periprosthetic fracture were used to compare ABG II with all other cementless femoral stems.

Result

ABG II stems accounted for 1% (2719 implants) of all femoral stem implants in Australia during the 12‐year review period, compared to 23% (587 implants) in Launceston Hospitals. Although the Launceston cumulative percent revision rate for the ABG II stem was lower than the National rate at all time points, the reasons for revision were similar. The most common reason for revision of ABG II was fracture (56.8%), followed by loosening (15.3%). This differs from the reasons for revision in other cementless prostheses (loosening 23.9%, fracture 20.8%, dislocation 18.7%). Cumulative percent revision rates from late periprosthetic fracture, were higher for the ABG II stem than other cementless femoral prostheses.

Conclusion

This review of the AOANJRR has confirmed a local and national higher revision rate of the ABG II stem due to late periprosthetic fracture compared with other cementless stems. Stem design must be considered to reduce the risk of late periprosthetic fracture.

Ten-year outcomes of cementless anatomical femoral implants after 3D computed tomography planning. Follow-up note

BACKGROUND

Pre-operative 3D planning based on computed tomography (CT) imaging is used to optimise the restitution of normal hip anatomy during primary total hip arthroplasty (THA). Although CT planning has been proven effective and reproducible, its influence on long-term THA outcomes is unknown. In this 10-year follow-up study of patients managed with the same technique of CT-planned primary anatomical THA, the objectives were to assess femoral implant survival, long-term functional outcomes, 10-year outcomes of titanium modular femoral necks, and associations with the dislocation rate. Hypothesis Pre-operative CT planning of primary THA ensures achievement of the NICE criterion of a lower than 5% femoral revision rate within 10 years.

MATERIAL AND METHODS

The study included 61 patients (61 hips) managed between 2004 and 2007 by CT-planned primary THA via the posterior approach, with an uncemented anatomical femoral component (SPS^®, Symbios); when deemed necessary by the surgeon to restore normal anatomy, a titanium modular femoral neck was used (35/61 patients). After 10 years, 17 patients had died and 3 were lost to follow-up, leaving 41 patients with a mean age of 76 years (range, 60-91 years) for re-evaluation. Clinical outcomes were assessed by determining the Harris Hip Score (HHS) and the Postel-Merle d'Aubigné (PMA) score, which were compared to baseline values. Radiographs were evaluated using the AGORA Roentgenographic Assessment system (ARA).

RESULTS

The 10-year femoral component survival rate was 96% (95%CI, 88;99%). Revision was required in 4 patients, to treat delayed peri-prosthetic fractures (n=2) or to correct initial cup malposition (n=2). No changes occurred from 2010 to last follow-up in the mean HHS (90 [95%CI, 84;95] and 91 [95%CI, 77;96], respectively) or mean PMA score (16 [95%CI, 14;17] and 15.5 [95%CI, 14;16.5], respectively). The mean ARA score was 5.2 (range, 3-6) at last follow-up. No complications related to the use of modular femoral necks were recorded. Dislocation occurred in 2 patients, but in neither was the pre-operative plan followed during surgery.

DISCUSSION

The SPS^® stem produced good 10-year clinical and radiographic outcomes. No patients experienced complications related to use of a titanium modular femoral neck. The restoration of anatomical hip geometry made possible by pre-operative CT planning provided sustained clinical improvements with a low complication rate.

LEVEL OF EVIDENCE

IV, retrospective observational cohort study.

Good stability of a cementless, anatomically designed femoral stem in aging women: a 9-year RSA study of 32 patients

Background and purpose - We previously reported a transient, bone mineral density (BMD)-dependent early migration of anatomically designed hydroxyapatite-coated femoral stems with ceramic-ceramic bearing surfaces (ABG-II) in aging osteoarthritic women undergoing cementless total hip arthroplasty. To evaluate the clinical significance of the finding, we performed a follow-up study for repeated radiostereometric analysis (RSA) 9 years after surgery. Patients and methods - Of the 53 female patients examined at 2 years post-surgery in the original study, 32 were able to undergo repeated RSA of femoral stem migration at a median of 9 years (7.8-9.3) after surgery. Standard hip radiographs were obtained, and the subjects completed the Harris Hip Score and Western Ontario and McMaster Universities Osteoarthritis Index outcome questionnaires. Results - Paired comparisons revealed no statistically significant migration of the femoral stems between 2 and 9 years post-surgery. 1 patient exhibited minor but progressive RSA stem migration. All radiographs exhibited uniform stem osseointegration. No stem was revised for mechanical loosening. The clinical outcome scores were similar between 2 and 9 years post-surgery. Interpretation - Despite the BMD-related early migration observed during the first 3 postoperative months, the anatomically designed femoral stems in aging women are osseointegrated, as evaluated by RSA and radiographs, and exhibit good clinical function at 9 years.

Comparison of an Uncemented Tapered Stem Design in Cobalt-Chrome vs Titanium at 15-Year Follow-Up

BACKGROUND

Cobalt-chromium (Co-Cr) and titanium (Ti) have been the most popular materials employed for cementless implants. The purpose of this study was to compare clinical and radiological results of a single stem design with both alloys at long-term follow-up.

METHODS

Two hundred consecutive uncemented stems implanted in 171 patients (100 Co-Cr and 100 Ti implants) between 1999 and 2002 were studied. Mean age of the patients was 60.9 years (range, 20-84). Clinical results were evaluated using the Harris hip score. The presence of thigh pain was also analyzed. Stem fixation was graded according to Engh criteria. Radiolucent lines, osteolysis, and stem subsidence were also analyzed.

RESULTS

At 15-year follow-up, no stems had been revised. Both groups showed similar clinical results with mean Harris hip score of 93.4 (Co-Cr) vs 93.9 (Ti). There was no difference in the rate of thigh pain (11 vs 8.3, respectively, P = .507). Radiolucent lines were more frequent in the Co-Cr group (63.6% vs 35.6%, P < .001).

CONCLUSION

Ti stems showed better osteointegration than Co-Cr stems, with a significantly lower incidence of radiolucent lines. However, this did not affect the clinical results or the appearance of thigh pain.

Effects of Nano-Hydroxyapatite/Polyetheretherketone-Coated, Sandblasted, Large-Grit, and Acid-Etched Implants on Inflammatory Cytokines and Osseointegration in a Peri-Implantitis Model in Beagle Dogs

Background

This study explored the effects of nano-hydroxyapatite/polyetheretherketone (n-HA/PEEK)-coated sandblasted, large-grit, and acid-etched (SLA) implants on inflammatory cytokines and osseointegration in peri-implantitis model beagle dogs.

Material/Methods

Peri-implantitis models were established. Eight beagle dogs were randomly and evenly assigned into SLA tied, SLA + n-HA/PEEK tied, SLA untied, or SLA + n-HA/PEEK untied groups. A special periodontal probe was used to detect the plaque index (PLI), probing depth (PD), and modified Sulcus Bleeding Index (mSBI). Gingival crevicular fluid was collected and an ELISA kit was utilized to detect IL-1, IL-6, and IL-17 levels. The colony-forming units were counted and the maximum shear strength of implants was tested using the axial pullout test. HE staining was used to detect the inflammation of peri-implant bone tissues. Osseointegration was observed through toluidine blue staining. Bone-to-implant contact (BIC) was obtained through histological observation and the mineral apposition rate (MAR) was calculated after immune fluorescent double staining.

Results

The SLA tied group demonstrated higher levels of PLI, PD, mSBI, IL-1, IL-6, and IL-17 and a higher degree of inflammation than the SLA + n-HA/PEEK tied group. The tied groups also displayed similar results over the untied groups at the same time point. The maximum shear strength, BIC, and MAR in the SLA tied group were significantly lower than in the SLA + n-HA/PEEK tied group.

Conclusions

Our findings demonstrate that SLA + n-HA/PEEK implants can promote osseointegration and relieve the inflammation response of peri-implantitis in beagle dogs.

Radiographic evaluation of early periprosthetic acetabular bone contrast and prosthetic head acetabular coverage after uncemented and cemented total hip prosthesis in dogs

BACKGROUND

Coxofemoral osteoarthritis is a chronic, disabling condition affecting people and dogs, with THA providing an excellent return to function in severely affected joints. The principal role of THA is to restore an adequate range of motion to the hip joint while transferring load from the acetabulum in order to improve the survival of the implant and enhance the limb function in the short and long terms. The objectives of the study reported here were, therefore, to radiographically evaluate periprosthetic acetabular bone GV and to assess prosthetic head acetabular coverage after 4 months of uncemented and cemented THA in dogs. Means periprosthetic acetabular GV for each and combined 3 regions of interest (zones 1, 2 and 3) were calculated immediately and 4 months after THA. Prosthetic head Norberg (PHN) angle was also measured to assess the degree of prosthetic head acetabular coverage after 4 months of surgery.

RESULTS

Zones 2 and 3 showed a significant increase in the mean bone GV after 4 months of uncemented THA. No differences in zones 1-3 after 4 months of cemented THA. Combined zones showed a significant increase in overall mean bone GV 4 months after uncemented THA; whereas, no changes were identified after 4 months of cemented THA. The PHN angles did not change after 4 months of uncemented and cemented THA and did not differ significantly between the 2 designs of hip arthroplasty.

CONCLUSIONS

Regional periprosthetic acetabular bone GV varies with the design of THA. None of the designs showed periprosthetic acetabular bone lucency. No differences identified in the degree of prosthetic head acetabular coverage in both designs, indicating proper implant stability after 4 months of surgery. Further longer-term investigation on larger population is however still warranted.

How to Approach a Recalled Dual Modular Hip Implant: An Update

BACKGROUND

The aim of this study was to provide an update on the "Modular taper junction corrosion and failure: how to approach a recalled total hip arthroplasty implant" (Pivec et al JOA 2014) publication.

METHODS

We performed a comprehensive review of the literature in English, with search terms referencing to the diagnosis, management, and outcomes of patients who underwent total hip arthroplasty with a recalled dual modular hip implant.

RESULTS

Based on this review and the new guidelines by the American Academy of Orthopedic Surgeons and the Hip Society, we propose an updated algorithm for the diagnosis and management of patients with these recalled implants.

CONCLUSION

When encountering patients with these prostheses, it is imperative to take a step-by-step approach to evaluate whether patients are having potential complications. We hope that this has further clarified the appropriate steps that need to be carried out when confronted with these recalled devices.

Changes in Femoral Version During Implantation of Anatomic Stems: Implications on Stem Design

BACKGROUND

Component positioning in total hip arthroplasty (THA) is among the primary indicators for longevity and success. Acetabular component positioning has been discussed in literature at length; however, femoral component positioning is also important as it contributes to combined anteversion.

METHODS

In this study, we examined the changes in femoral anteversion after the implantation of anatomic stem ABG II. A cadaveric study, a computed tomography-based computer modeling study, and a clinical study using a navigation system were conducted to document these changes.

RESULTS

These studies demonstrated that the anatomic stem ABG II increased the postimplantation femoral version by approximately 7°. The postimplantation versions followed a bimodal distribution. The computed tomography and navigation data also highlighted that the patient population may roughly be divided into 2 groups: the first group that needs anteverted stem and the second group that needs little or no anteversion in the stem to recreate the desired version and offset.

CONCLUSION

Based upon our data, we propose a new anatomic stem design that is offered in 2 version angles of 0° and 7° to help create the desired version and offset.

Results of Cemented Anatomically Adapted Total Hip Arthroplasty: A Follow-Up Longer Than 10 years

This retrospective single-center study evaluated the >10-year follow-up (FU) and survival of 2 anatomically adapted cemented total hip arthroplasties (THAs) in a series of 308 patients (323 THAs) with a mean age of 76.2 years at operation. At a mean of 11 years of FU, patient-reported outcome measures, clinical examination, and plain radiography were analyzed. In 6 THAs, the femoral and/or acetabular component was revised. Reasons for revision were aseptic loosening and infection. At >10 years of FU, there was an overall survival for both THAs of 98.1%. Radiographic radiolucent lines were seen in 15 THAs affecting Gruen zone 4 and Delee and Charnley zone II. We conclude that both anatomically adapted cemented THAs have an excellent survival at 11 years of FU.

Cementless hydroxyapatite coated hip prostheses

More than twenty years ago, hydroxyapatite (HA), calcium phosphate ceramics, was introduced as a coating for cementless hip prostheses. The choice of this ceramic is due to its composition being similar to organic apatite bone crystals. This ceramic is biocompatible, bioactive, and osteoconductive. These qualities facilitate the primary stability and osseointegration of implants. Our surgical experience includes the implantation of more than 4,000 cementless hydroxyapatite coated hip prostheses since 1990. The models implanted are coated with HA in the acetabulum and in the metaphyseal area of the stem. The results corresponding to survival and stability of implants were very satisfactory in the long-term. From our experience, HA-coated hip implants are a reliable alternative which can achieve long term survival, provided that certain requirements are met: good design selection, sound choice of bearing surfaces based on patient life expectancy, meticulous surgical technique, and indications based on adequate bone quality.