Fifteen-year to twenty-year results of cementless Harris-Galante porous femoral and Harris-Galante porous I and II acetabular components

Minimal Influence on Muscle Strength and Patient Reported Outcome Measures by Conjoined Tendon Detachment in Anterolateral Muscle-Sparing Total Hip Arthroplasty

Purpose

The conjoined external rotator tendon (CERT), composed of the tendons of the gemellus superior, obturator internus (OI), and gemellus inferior muscles, stabilizes the hip joint. The study investigates the clinical and radiological effects of the CERT release during anterolateral-supine approach (ALSA) total hip arthroplasty (THA).

Methods

A cohort of 60 patients who underwent ALSA THA was examined. Pre- and post-operative muscle width, muscle strength, and radiological data were compared between the CERT-detached and preserved groups. In addition, Clinical assessments were performed using the Japanese Orthopaedic Association Hip-Disease Evaluation Questionnaire and the short-form 36 questionnaires.

Results

58.3% had CERT detached, resulting in radiological atrophy of the OI muscle. Despite this, hip flexion, extension, and abduction muscle strength significantly improved at 6 months post-surgery. The detached CERT did not substantially affect patient-reported outcome measures, including pain and daily activities, within the 6-month follow-up.

Discussion

The study suggests that while CERT detachment can lead to muscle atrophy, it has a limited impact on muscle strength and patient-reported outcome measures, indicating the muscle's potential redundancy. Preserving the CERT might enhance stability and prevent atrophy but could increase the risk of complications. CERT release is recommended when femur exposure is inadequate.

The intraoperative hip range of motion in total hip arthroplasty predicts postoperative patient's satisfaction for cutting toenails and putting on sock

BACKGROUND

Restricted hip range of motion (ROM) has been proposed as a useful diagnostic tool for osteoarthritis. The relations between the intraoperative hip ROM under anesthesia in total hip arthroplasty (THA) and recovery of clinical mobility outcomes were unclear. This study evaluated the association between the intraoperative hip ROM under anesthesia in THA and the postoperative recovery of clinical mobility, including cutting toenails and putting on socks after THA.

METHODS

The study was performed as a prospective cohort study and included 93 hips in 85 patients who underwent primary anterior-based muscle-sparing THA in the supine position. The hip ROM was evaluated under anesthesia before skin incision and intraoperative stability test. The Japanese Orthopaedic Association Hip-Disease Evaluation Questionnaire (JHEQ) was evaluated. A questionnaire on whether and how patients could cut toenails and putting on socks was assessed. The relationship between hip ROM at intraoperative stability tests and JHEQ moving score, cutting toenails, and putting on socks scores were evaluated statistically.

RESULTS

We observed a week positive correlation between intraoperative hip ROM and the total of JHEQ mobility score. A moderate positive correlation was observed between external rotation angle with flexion 90°and cutting toenails and putting on socks score oh JHEQ. 94.6% and 96.8% of the patients could cut their toenails and putting on socks by themselves after surgery. The optimum cutoff range for high patient satisfaction for putting on socks and cutting toenails was 110° for flexion and 35°-40° for the external rotation angle in the intraoperative stability test.

CONCLUSION

Hip ROM during intraoperative stability testing, especially the external rotation angle can predict postoperative outcomes and patient satisfaction for cutting toenails and putting on socks. We suggested that the capsule or capsular ligament release around the hip was increased to provide sufficient ROM without compromising stability.

Association between Hip Center Position and Isokinetic Hip Muscle Performance after Anterolateral Muscle-Sparing Total Hip Arthroplasty

Background and objectives: The superior placement of the acetabular cup induced the delayed recovery of abductor muscle moment after total hip arthroplasty (THA) with a conventional posterior approach. The anterior-based muscle-sparing (ABMS) THA effectively reduces soft tissue damage, including muscles. The influence of hip center position on anterior-based muscle-sparing (ABMS) total hip arthroplasty (THA) for post-operative hip muscle strength was unclear. We evaluate whether the hip center position affects the recovery of hip muscle strength after ABMS THA. Materials and Methods: The study was performed as a retrospective cohort study, and included 38 hips in 38 patients that underwent primary ABMS THA. Muscle strength was measured using isokinetic dynamometry before the operation, and at 6 and 12 months after surgery. The horizontal and vertical centers of rotation (H-COR and V-COR), vertical shift (V-shift), leg length, and global femoral offset were determined radiographically in reference to a previous report. Results: A weak negative correlation was observed between abduction muscle strength at 6 months and V-shift; a V-shift more than 15 mm demonstrated significantly decreased abductor muscle strength at 6 months. Conclusions: The superior placement of the hip center caused delayed recovery of abductor muscle strength in hips with anterolateral minimally invasive THA. There seems to exist no biomechanical reason why the same should not also be the case for the muscle-sparing approach.

Average 22-Year Results of Total Hip Arthroplasty Using Harris-Galante Prosthesis in Patients under 50 Years

Background

The Harris-Galante (HG) prosthesis is a first-generation, cementless total hip arthroplasty (THA) prosthesis. Considering the recent increase in the demand for THA in young patients and their life expectancy, a study with a follow-up duration of longer than 20 years in a young population is needed. Therefore, we evaluated the long-term clinical and radiographic results after cementless THA using the HG prosthesis in patients younger than 50 years.

Methods

A total of 61 THAs performed using the HG with a minimum follow-up of 10 years were included. There were 38 men and 11 women with an average age of 46 years and the mean follow-up duration was 22 years. Clinical evaluation included modified Harris Hip Score (HHS) and radiographic analysis consisted of cup inclination, anteversion angle, component stability, osteolysis, liner wear rate, wear-through, liner dissociation, and heterotopic ossification. Complications included recurrent dislocation, periprosthetic femoral fracture, and periprosthetic joint infection. Survivorship analysis included cup and stem revision for aseptic loosening, as well as any revision.

Results

The HHS improved from 46.5 preoperatively to 81.8 postoperatively (p < 0.001). The average linear wear rate was 0.36 mm/yr. A total of 34 hips (56%) were revised: stem revision in 10 (16.4%), cup revision in 9 (14.8%), exchange limited to bearing surface in 8 (13.1%), and revision of all components in 7 (11.5%). Estimated survivorship at 34 years postoperatively was 90.9% for cup revision for aseptic loosening, 80.5% for stem revision for aseptic loosening, and 22.1% for any revision.

Conclusions

THA using the HG prosthesis showed satisfactory estimated survivorship of the acetabular and femoral components at 34 years postoperatively with good clinical outcomes. Bearing-related problems, such as osteolysis and liner dissociation, accounted for 56% of revision operations and were concerns in patients younger than 50 years.

Limited effects on patient outcomes of conjoint tendon release in anterolateral muscle-sparing total hip arthroplasty

Background

The anterolateral muscle-sparing total hip arthroplasty (THA) in the supine position is advantageous owing to the very low-dislocation rate and excellent leg length discrepancy control. However, femur exposure is challenging. Although the conjoined external rotators tendon (CERT) release is effective in improving femoral access, the effects on clinical outcomes remain unclear. The purpose of this study was to evaluate the clinical and radiographic results of CERT release in the anterolateral muscle-sparing THA approach.

Methods

The study was performed as a retrospective cohort study and included 85 hips in 85 patients who underwent primary anterolateral THA. Clinical and radiographic outcomes were investigated 6 months and 1 year after THA (CERT-preserved and non-released patients). The Japanese Orthopaedic Association (JOA) hip score, JOA Hip-disease Evaluation Questionnaire (JHEQ), forgotten joint score (FJS), and the 36 short-form questionnaires (SF-36 mental and physical) were evaluated. The leg length discrepancy, cup inclination and stem orientation were evaluated with radiographs.

Results

Among all the included hips, 37 patients (43.5%) retained the CERT, and 48 patients (56.5%) included the released CERT. There were no significant differences in the JOA hip scores, JHEQ, FJF-12 and SF-36 between the released and non-released groups. There were significant differences in sagittal stem alignments between groups.

Conclusion

The CERT release in anterolateral muscle-sparing THA has a limited effect on post-operative clinical outcomes. The CERT release improved the femur exposure and is more invasive than the preserved CERT. We infer that the CERT should be maintained in patients with a wide range of motions, and release the CERT in inadequate femur canal preparation cases.

Long-Term Outcomes for Cementless Anatomic Femoral Components, Compared by Area of Porous Coating, in Patients Younger Than 50 Years Treated for Hip Dysplasia

BACKGROUND

We investigated whether the proximal circumferential porous coating of cementless stems would make implant survival of >20 years possible in young patients.

METHODS

Data for patients younger than 50 years with hip dysplasia who had an anatomic stem implanted with a proximal porous coating with hydroxyapatite/tricalcium phosphate were reviewed. Noncircumferential porous (non-C-type) stems were used in 17 hips (13 cases), and circumferential porous (C-type) stems were used in 87 hips (68 cases). Acetabular components with conventional polyethylene were used for all hips. The mean ages at surgery for patients with non-C-type stems and those with C-type stems were 43.3 and 44.7 years, respectively. Stems that had not loosened were retained at the time of acetabular revision. The average duration of follow-up for patients with non-C-type stems was 26.9 years and was 22.3 years for those with C-type stems.

RESULTS

Mean survival rates as determined by the Kaplan-Meier method were 74.9% at 20 years and 59.9% at 25 years for non-C-type stems and were 100% at 20 years and 94.0% at 25 years for C-type stems. The survivorship for C-type stems was significantly higher than that for non-C-type stems (P < .01). Focal osteolysis in the shoulder of 37 hips with C-type stems suppressed the spread of osteolysis to the distal femur.

CONCLUSION

Anatomic femoral stems with a circumferential porous coating provide excellent durability in patients with hip dysplasia who are 50 years of age or younger.

LEVEL OF EVIDENCE

Therapeutic Level IV.

Mid-term result of acetabular reconstruction using a Kerboull-type acetabular reinforcement device with hydroxyapatite impaction

The aim of this study is to investigate the mid-term results of 29 hips in 26 patients who underwent acetabular reconstruction using a Kerboull-type acetabular reinforcement device and impaction with hydroxyapatite (HA) granules. The acetabular bone defects were AAOS type II for six hips and type III for 23 hips. The mean Merle d’Aubigné clinical scores were significantly improved after operation. Six hips developed implant migration and breakage, and five of six hips were revised after an average of 5.5 (range 2.0–8.8) years. All hips with thickness of the grafted HA less than 10 mm were stable. As the HA became thicker, the failure rate were significantly increased. The Kaplan–Meier survival rates at 10 years were 73.2%, with 100% and 67.0% for AAOS type II and III defect respectively as the end point was failure condition. Reconstruction using a Kerboull-type acetabular reinforcement device and impaction with HA granules was an alternative method in the absence of adequate allografts.

Osteoconductivity of bioactive Ti-6Al-4V implants with lattice-shaped interconnected large pores fabricated by electron beam melting

Additive manufacturing has facilitated the fabrication of orthopedic metal implants with interconnected pores. Recent reports have indicated that a pore size of 600 μm is beneficial for material-induced osteogenesis. However, the complete removal of the metal powder from such small pores of implants is extremely difficult especially in electron beam melting (EBM). We therefore developed a new type of Ti-6Al-4V implant with lattice-shaped interconnected pores measuring 880-1400 μm, which allowed for the easy removal of metal powder. This implant was fabricated by EBM and treated with NaOH, CaCl₂, heat, and water (ACaHW treatment) to render the metal surface bioactivity. In the present study, the mechanical and chemical property of the implants and the biocompatibility were evaluated. The SEM and micro-CT images demonstrated the 3D interconnectivity of the porous structures. The average porosity of the porous titanium implant was 57.5%. The implant showed maximum compressive load of 78.9 MPa and Young's modulus of 3.57 GPa which matches that of human cortical bone. ACaHW treatment of the porous Ti-6Al-4V implants induced apatite formation in simulated body fluid in vitro. The ACaHW-treated porous implants harvested from rabbit femoral bone showed direct bonding of bone to the metal surface without interposition of fibrous tissue. The porous ACaHW-treated implant had a higher affinity to the bone than the untreated one. The mechanical strength of implant fixation assessed using the push-out test was significantly higher in the ACaHW-treated implant than in untreated one. FE-SEM analysis and EDX mapping after push-out test of solid implants showed a lot of bone tissue patches on the surface of the ACaHW-treated implant. These results suggest that the new ACaHW-treated Ti-6Al-4V implant with lattice-shaped interconnected pores is a superior alternative to conventional materials for medical application.

The incidence of dissociated liners in 4,751 consecutive total hip arthroplasties using Pinnacle polyethylene acetabular liners

INTRODUCTION

Acetabular liner dissociation is a complication exclusive to modular designs. We present a single surgeon series of 8 polyethylene liner dissociations with the Pinnacle Acetabular System (DePuy Orthopaedics) from over 4,750 cases. We also present a review of the literature and data from the UK National Joint Registry (NJR) on dissociation in total hip arthroplasty (THA).

METHODS

The Pinnacle Acetabular System has been used exclusively by the senior author since April 2003, and to date 5,882 have been implanted (837 ceramic liners, 4,751 polyethylene liners (1,606 Enduron/3,145 Marathon) and 294 metal liners). We reviewed all cases of liner dissociation from this cohort to determine an overall incidence with polyethylene liners, identify associated risk factors, and report the outcome following revision surgery.

RESULTS

Our incidence of this complication is 8 out of 4,751 cases (0.17%). Review of these cases and the literature suggests that femoral neck impingement against the polyethylene liner and/or edge loading may produce fatigue failure of the locking mechanism and subsequent dissociation.

CONCLUSIONS

Ensuring correct liner seating/locking, minimising impingement, achieving appropriate component version and avoiding radiographic cup inclinations >50° should minimise the risk of liner dissociation. Any new noise or squeaking from a polyethylene liner should undergo radiographic investigation to exclude dissociation. We recommend managing late cases of liner dissociation with revision of the acetabular shell if the cup orientation could be improved or if there is any damage to the liner-locking groove, to reduce the risk of recurrence.

A review of outcomes and modes of presentation following liner dissociation from Harris-Galante uncemented acetabular components

PURPOSE

Dissociation of the polyethylene liner is a known failure mechanism of the Harris Galante I and II uncemented acetabular components. The outcomes of revision surgery for this indication and the influence of time to diagnosis are not well described.

METHODS

We report a series of 29 cases revised due to this failure mechanism. The median time from primary to revision surgery was 13 years.

RESULTS

At a median of 4 years follow-up, the mean OHS was 34 (range 6-48) but results were poorer (mean 29; range 6-45) when the diagnosis and revision was delayed compared to when it was not (mean 39; range 20-48). A large proportion of our patients (n = 14) presented with sudden onset of symptoms with or without trauma. Osteolysis was common in this series but the cup was well fixed in 20/29 cases. There was macroscopic damage to the shell in all cases.

CONCLUSIONS

In our experience, prompt revision of liner dissociation optimises outcomes in this group of patients and radiology reporting alone is not sufficient to identify these cases.

ORIF or Arthroplasty for Displaced Femoral Neck Fractures in Patients Younger Than 65 Years Old: An Economic Decision Analysis

BACKGROUND

The decision between open reduction and internal fixation (ORIF) and arthroplasty for a displaced femoral neck fracture in a patient ≤65 years old can be challenging. Both options have potential drawbacks; if a fracture treated with ORIF fails to heal it may require a revision operation, whereas a relatively young patient who undergoes arthroplasty may need revision within his/her lifetime. The purpose of this study was to employ decision analysis modeling techniques to generate evidence-based treatment recommendations in this clinical scenario.

METHODS

A Markov decision analytic model was created to simulate outcomes after ORIF, total hip arthroplasty (THA), or hemiarthroplasty in patients who had sustained a displaced femoral neck fracture between the ages of 40 and 65 years. The variables in the model were populated with values from studies with high-level evidence and from national registry data reported in the literature. The model was used to estimate the threshold age above which THA would be the superior strategy. Results were tested using sensitivity analysis and probabilistic statistical analysis.

RESULTS

THA was found to be a cost-effective option for a displaced femoral neck fracture in an otherwise healthy patient who is >54 years old, a patient with mild comorbidity who is >47 years old, and a patient with multiple comorbidities who is >44 years old. The average clinical outcomes of THA and ORIF were similar for patients 40 to 65 years old, although ORIF had a wider variability in outcomes based on the success or failure of the initial fixation. For all ages and cases, hemiarthroplasty was associated with worse outcomes and higher costs.

CONCLUSIONS

Compared with ORIF, primary THA can be a cost-effective treatment for displaced femoral neck fractures in patients 45 to 65 years of age, with the age cutoff favoring THA decreasing as the medical comorbidity and risk of ORIF fixation failure increase. Hemiarthroplasty has worse outcomes at higher costs and is not recommended in this age group.

LEVEL OF EVIDENCE

Economic and decision analysis Level III. See Instructions for Authors for a complete description of levels of evidence.

Patient-specific hip geometry has greater effect on THA wear than femoral head size

In vivo linear penetration in total hip arthroplasty (THA) exhibits similar values for 28mm and 32mm femoral head diameter with considerable variations between and within the studies. It indicates factors other than femoral head diameter influence polyethylene wear. This study is intended to test the effect of patient׳s individual geometry of musculoskeletal system, acetabular cup orientation, and radius of femoral head on wear. Variation in patient׳s musculoskeletal geometry and acetabular cup placement is evaluated in two groups of patients implanted with 28mm and 32mm THA heads. Linear wear rate estimated by mathematical model is 0.165-0.185mm/year and 0.157-0.205mm/year for 28 and 32mm THA heads, respectively. Simulations show little influence femoral head size has on the estimated annual wear rate. Predicted annual linear wear depends mostly on the abduction angle of the acetabular cup and individual geometry of the musculoskeletal system of the hip, with the latter having the greatest affect on variation in linear wear rate.

The 21- to 27-year results of the Harris-Galante cementless total hip arthroplasty

BACKGROUND

The Harris-Galante total hip arthroplasty (THA) is a first-generation cementless THA with a porous coating for biological fixation of the implant. Many studies report excellent long-term results for the acetabular cup, but few long-term studies exist for the femoral stem because of relatively poor short-term and midterm results. Here we present the 21- to 27-year results of the cup and the stem of the Harris-Galante THA.

METHODS

From 1985 to 1991, 102 Harris-Galante THAs were inserted in 82 patients. At the time of the THA, the mean patient age was 54 years (range, 20-78 years). The primary diagnosis was secondary osteoarthritis due to developmental hip dysplasia (69 [68%] hips). The Japanese Orthopaedic Association (JOA) hip score and thigh pain were measures of clinical outcome. Radiographic review was performed retrospectively. Implant survival was evaluated by Kaplan-Meier analysis.

RESULTS

Of 102 hips, 35 hips were from 31 deceased patients, 5 patients (6 hips) were lost to follow-up, 12 hips were revised, and 49 hips were from patients living at the latest follow-up. Among the living patients, 36 hips had a clinical evaluation and 42 hips had a radiograph obtained more than 21 years. The JOA hip score improved from 42 points preoperatively to 83.5 points at the latest follow-up. Thigh pain was reported in 13 hips. One cup and four stems were loose at the latest radiographic review. Most cup revisions were related to acetabular osteolysis. Fifteen hips showed severe stress shielding. Kaplan-Meier analysis of survivorship with any revision, acetabular reoperation, stem revision, and stem loosening as the end point was 87.0%, 90.3%, 95.7% and 86.4%, respectively, at 24.6 years.

CONCLUSIONS

Long-term implant survival and clinical results of the Harris-Galante THA were good. Acetabular osteolysis-related cup loosening was a problem of the cup. Loosening, thigh pain, and stress shielding were problems of the stem.

AVASCULAR NECROSIS OF THE FEMORAL HEAD IN HIV-INFECTED PATIENTS: PRELIMINARY RESULTS FROM SURGICAL TREATMENT FOR CERAMIC-CERAMIC JOINT REPLACEMENT

Objectives: To evaluate the initial functional results and early complication rate of ceramic-ceramic total hip replacements among patients living with HIV who presented osteonecrosis of the femoral head. Method: Twelve HIV–positive patients with a diagnosis of osteonecrosis of the incongruent femoral head were evaluated using clinical and laboratory criteria and the WOMAC functional scale before and after treatment with joint replacement. Results: We observed that 83.3% of the subjects were taking protease inhibitors, 75% had dyslipidemia and 66.6% had lipodystrophy syndrome. The improvement over the evolution of the WOMAC score was statistically significant at six and twelve months after the operation, in comparison with the preoperative score. We did not observe complications secondary to this procedure. Conclusion: Total hip arthroplasty with a ceramic-ceramic implant for treating avascular necrosis of the hip is an appropriate surgical option for this portion of the population. It provides a significant initial functional improvement and a low early complication rate.

Long-term outcome of a metal-on-polyethylene cementless hip resurfacing

Due to the well-documented problems surrounding metal-on-metal bearings, the use of hip resurfacing has declined. Since the potential benefits of hip resurfacing remain desirable, it may be beneficial to investigate the long-term outcome of hip resurfacings using metal-on-polyethylene in the 1980's. We report the long-term survivorship and modes of failure of a cementless metal-on-polyethylene resurfacing (n = 178) with different porous ingrowth surfaces. While acetabular loosening was absent, a high incidence of femoral failures (femoral loosening = 18.1%, osteolytic neck fracture = 21%) occurred despite using the same ingrowth surface for both components. Ongoing developments using the lessons learned from these previous generation components and utilizing modern low wear materials, e.g., cross-linked polyethylene, may lead to improved implants for future hip resurfacings.

Clinical and Radiographic Outcomes with a Hydroxyapatite and Porous Coated Cup Design

Press-fit, hydroxyapatite-coated acetabular cup designs may offer a lower incidence of loosening and migration than older designs. Our study evaluated the initial clinical and radiographic success of a cementless acetabular shell in a large cohort of primary total hip arthroplasty (THA) patients. We queried our institution’s prospectively collected registry for a series of 771 primary THAs (695 patients) implanted with this cup by 4 high-volume arthroplasty surgeons. Of the 613 hips with minimum 2-year followup, average HHS (Harris Hip Score) was 93.6, WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) was 87.6, and VAS (Visual Analog Scale) pain score was 1.2. While there was a 2% reoperation rate (12 hips), none of the cups were revised for aseptic loosening. No radiolucencies were found and there was no evidence of acetabular loosening. At early followup, this newer cementless acetabular cup implant design exhibits high survivorship and clinical success.

Poor short term outcome with a metal-on-metal total hip arthroplasty

Metal-on-metal (MoM) bearings for total hip arthroplasty (THA) have come under scrutiny with reports of high failure rates. Clinical outcome studies with several commercially available MoM THA bearings remain unreported. We evaluated 78 consecutive MoM THAs from a single manufacturer in 68 patients. Sixty-six received cobalt-chrome (CoCr) monoblock and 12 received modular titanium acetabular cups with internal CoCr liners. Femoral components were titanium with modular necks. At average 2.1 years postoperatively, 12 THAs (15.4%) demonstrated aseptic failure (10 revisions, 2 revision recommended). All revised hips demonstrated capsular necrosis with positive histology reaction for aseptic lymphocytic vasculitis-associated lesions/adverse local tissue reactions. Prosthetic instability following revision surgery was relatively common. Female gender was a strong risk factor for failure, though smaller cups were not. Both monoblock and modular components fared poorly. Corrosion was frequently observed around the proximal and distal end of the modular femoral necks.

In vitro osteoblast response to ferritic stainless steel fiber networks for magneto-active layers on implants

The use of a porous coating on prosthetic components to encourage bone ingrowth is an important way of improving uncemented implant fixation. Enhanced fixation may be achieved by the use of porous magneto-active layers on the surface of prosthetic implants, which would deform elastically on application of a magnetic field, generating internal stresses within the in-growing bone. This approach requires a ferromagnetic material able to support osteoblast attachment, proliferation, differentiation, and mineralization. In this study, the human osteoblast responses to ferromagnetic 444 stainless steel networks were considered alongside those to nonmagnetic 316L (medical grade) stainless steel networks. While both networks had similar porosities, 444 networks were made from coarser fibers, resulting in larger inter-fiber spaces. The networks were analyzed for cell morphology, distribution, proliferation, and differentiation, extracellular matrix production and the formation of mineralized nodules. Cell culture was performed in both the presence of osteogenic supplements, to encourage cell differentiation, and in their absence. It was found that fiber size affected osteoblast morphology, cytoskeleton organization and proliferation at the early stages of culture. The larger inter-fiber spaces in the 444 networks resulted in better spatial distribution of the extracellular matrix. The addition of osteogenic supplements enhanced cell differentiation and reduced cell proliferation thereby preventing the differences in proliferation observed in the absence of osteogenic supplements. The results demonstrated that 444 networks elicited favorable responses from human osteoblasts, and thus show potential for use as magnetically active porous coatings for advanced bone implant applications.

Successful long-term fixation and progression of osteolysis associated with first-generation cementless acetabular components retrieved post mortem

BACKGROUND

Primary cementless acetabular reconstruction has shown durable long-term fixation. Late failures secondary to aseptic loosening are rare but may occur in patients with previously well-fixed components. In the present study, the histopathological characteristics of postmortem specimens were correlated with wear damage and radiographic data in an attempt to better understand the long-term events in the periacetabular tissue around well-functioning devices.

METHODS

Seventeen primary cementless Harris-Galante I acetabular components with adjacent tissues were harvested after a mean of eleven years (range, four to twenty-five years) from patients whose implants were well functioning at the time of death. Undecalcified and paraffin sections were used to quantify the extent of bone and soft tissues within the porous coating and at the interface between the coating and the surrounding bone. Wear particles were identified with use of polarized light microscopy and energy-dispersive x-ray analysis. Bearing-surface volumetric wear and backside wear damage of the polyethylene liner were assessed.

RESULTS

All of the components were fixed by bone ingrowth (mean extent, 33% ± 21%). Particle-induced granulomas were present in the porous coating and along the interface and progressed through screw holes, ballooning into the retroacetabular bone in the longer-term specimens. Particles of femoral and acetabular origin were identified in the granulomas. Bearing-surface volumetric wear (mean, 41.6 mm3/year) increased with duration and correlated with increasing extent of granuloma in the porous coating and the increasing size of pelvic granulomas. Radiolucencies on radiographs correlated with the extent of bone and fibrous tissue ingrowth. Of the six pelvic granulomas that were identified histologically, only one was apparent on routine radiographs.

CONCLUSIONS

Acetabular fixation by bone ingrowth can be successful into the third decade after implantation. Osteolysis and secondary replacement of bone with particle-induced granuloma are commonly seen in the presence of excellent clinical function. Strategies designed to minimize bearing-surface wear and backside damage are important to maintain long-term bone ingrowth fixation.

Simultaneous bilateral total hip arthroplasty with hydroxyapatite-coated implants: a 20-year follow-up

Bilateral hip arthroplasty has been reported to be a safe and effective way to treat bilateral hip arthritis in a selective group of patients. We report a follow-up of 30 patients who underwent simultaneous bilateral total hip arthroplasty with hydroxyapatite implants and were followed for an average of 19.4 years. Patients had an average Harris Hip Score of 90 at the latest follow-up (range, 78-99). The average Western Ontario and McMaster Universities Arthritis Index questionnaire index score was 12 (range, 0-41), with high functional results on the 12-Item Short Form Health Survey (SF-12) and Oxford 12 questioners. Using the Kaplan-Meier survivorship analysis, with revision for any reason as an end point, survivorship was 94% at 12 years, 88% at 15 years, 74% at 18 years, and 61% at 23 years. All revisions were for the acetabular component, and the survivorship for the femoral component was 100% throughout the 23-year period. We conclude that bilateral uncemented total hip arthroplasty can provide satisfactory long-term clinical, radiological, and functional outcomes in patients even with older-generation polyethylene liners and stem designs.

15-year comparison of cementless total hip arthroplasty with anatomical or high cup placement for Crowe I to III hip dysplasia

This study compared radiological and clinical results of Mallory-Head (Biomet, Warsaw, Indiana) cementless total hip arthroplasty (THA) by anatomical (AP group) or high cup placement (HP group) for Crowe I to III developmental dysplasia of the hip. Of the 68 hips studied, 43 hips were available for 15.3-year follow-up. Ten cups were placed at anatomical center with bulk bone grafting, and 33 cups were at high hip center without bulk bone grafting. No acetabular or femoral components showed loosening in either group. One standard polyethylene liner in a highly placed cup was revised due to excessive wear after 11 years. The average rate of polyethylene wear was 0.128 mm/year in the AP group and 0.148 mm/year in the HP group (except for the revision case). The extent of grafted bone coverage was 34.6% in the AP group. Hip center height was 24.5 mm from the inter-teardrop line in the HP group. The center of the hip horizontal location in the AP group (24.5 mm) and HP group (26.4 mm) was significantly shorter than in normal hips (35.6 mm). Postoperative center-edge angle was 11° (except grafted bone) in the AP group and 25° in the HP group. Mean Harris Hip Score in the AP group improved from 38 points preoperatively to 82 points postoperatively and in the HP group improved from 40 points preoperatively to 88 points postoperatively. Survivorship was 100% in the AP group and 97% in the HP group. Our results indicate that moderate high cup placement without bulk bone grafting at a horizontal locus more medial than that of a normal hip is an alternative durable solution.

Total hip arthroplasty: to cement or not to cement the acetabular socket? A critical review of the literature

The optimal method for acetabular socket fixation remains controversial. We present a critical analysis of the current evidence from a systemic literature review of comparative studies, long-term case series, prior literature reviews, meta-analysis, and national arthroplasty registry data for cemented and uncemented acetabular components to determine the respective survivorship rates, overall risk of re-operation, dislocation rates, and wear-related complications. Using contemporary techniques, both cemented and uncemented sockets can yield good long-term results, but our evaluation suggests that the overall/all cause re-operation risk is lower for cemented fixation. Until and unless crosslinked polyethylene (PE) liners or alternative bearings can prove to yield superior outcome in the future, the cemented PE cup remains the gold standard, in all age groups, by which every acetabular component should be compared.

Development of a femoral stem providing strong anchorage and facilitated removal. An experimental study in goats

OBJECTIVE

Prosthetic elements must be securely anchored to bone. Should revision surgery be necessary, preservation of bone stock is crucial. The goal of this study was to develop and assess a femoral stem combining secure anchorage and facilitated removal in a goat model.

METHODS

The development of the uncemented femoral stem was part of an innovation process to fulfill the combined requirements. The stem was designed with two longitudinal semicircular grooves to accommodate a drill bit to unanchor the stem. These grooves were interconnected by canals, each 1 mm in diameter. The surface was partly coated with hydroxyapatite (HA). The stems were inserted in the left hip of 35 goats. Perioperatively, the grooves were filled with autologous bone grafts, and standard cemented canine acetabular component and head were used. The pull-out force was measured six months postoperatively. Following randomization, 11 animals had the grooves of the stem drilled to remove anchoring tissue. Twelve animals were left undrilled (controls).

RESULTS

There was a significant difference in mean pull-out force between the group that had been drilled (1526 N) compared with the controls (2033 N, p = 0.028). Most of the HA had been resorbed.

CLINICAL SIGNIFICANCE

The stems had a high retention force. The procedure for un-anchoring by drilling significantly reduced the pull-out force.

Results of 3,668 primary total hip replacements for primary osteoarthritis in patients under the age of 55 years

BACKGROUND AND PURPOSE

In a previous study based on the Finnish Arthroplasty Register, the survival of cementless stems was better than that of cemented stems in younger patients. However, the survival of cementless cups was poor due to osteolysis. In the present study, we analyzed population-based survival rates of the cemented and cementless total hip replacements in patients under the age of 55 years with primary osteoarthritis in Finland.

PATIENTS AND METHODS

3,668 implants fulfilled our inclusion criteria. The previous data included years 1980-2001, whereas the current study includes years 1987-2006. The implants were classified in 3 groups: (1) implants with a cementless, straight, proximally circumferentially porous-coated stem and a porous-coated press-fit cup (cementless group 1); (2) implants with a cementless, anatomic, proximally circumferentially porous-coated stem, with or without hydroxyapatite, and a porous-coated press-fit cup with or without hydroxyapatite (cementless group 2); and (3) a cemented stem combined with a cemented all-polyethylene cup (the cemented group). Analyses were performed separately for 2 time periods: those operated 1987-1996 and those operated 1997-2006.

RESULTS

The 15-year survival for any reason of cementless total hip replacement (THR) group 1 operated on 1987-1996 (62%; 95% CI: 57-67) and cementless group 2 (58%; CI: 52-66) operated on during the same time period was worse than that of cemented THRs (71%; CI: 62-80), although the difference was not statistically significant. The revision risk for aseptic loosening of cementless stem group 1 operated on 1987-1996 (0.49; CI: 0.32-0.74) was lower than that for aseptic loosening of cemented stems (p = 0.001).

INTERPRETATION

Excessive wear of the polyethylene liner resulted in numerous revisions of modular cementless cups. The outcomes of total hip arthroplasty appear to have been relatively unsatisfactory for younger patients in Finland.

The Harris-Galante cementless THA: a 19- to 25-year follow-up study

The goal of this study was to evaluate the long-term survivorship of primary cementless total hip arthroplasty (THA) using Harris-Galante porous I acetabular and Harris-Galante porous femoral components. From July 1985 to December 1991, we performed primary cementless THA on 76 hips (70 patients). Twenty-nine patients (31 hips) died due to causes unrelated to the THA, and 6 patients (7 hips) were lost to follow-up. Of 76 hips (70 patients) studied, 38 hips (35 patients) were available for follow-up at a mean 22.5 years (range, 19-25 years) postoperatively. Mean patient age at index procedure was 51.2 years (range, 42-65 years). Average Harris Hip Score was 40.5 points preoperatively and 85.8 points at final follow-up. No patient had an early or late postoperative deep infection. Radiographically, the acetabular component fixation was stable in all 38 hips. The femoral component was bone-ingrown in 26 hips, stable-fibrous in 10, and unstable in 2. One unstable hip required revision of the femoral component. Dissociation of the polyethylene liner occurred in 3 hips without fractures of the metal locking tines and required revision of the polyethylene liner and the articular head. A total of 4 hips had documented revision, and 1 femoral component failed radiographically. The survival rate with the endpoint defined as revision surgery and radiographic loosening was 86.8% at 22.5 years of follow-up. Mean polyethylene wear was 0.085 mm/year (range, 0.031-0.15 mm). This study found that the Harris-Galante porous I acetabular and Harris-Galante porous femoral components produce excellent long-term results.

Excellent results with cementless total hip arthroplasty and alumina-on-alumina pairing: minimum ten-year follow-up

Ceramic-on-ceramic coupling is thought to be a durable alternative to metal- or alumina-on-polyethylene pairing. No evidence exists suggesting superior clinical and radiological results for hydroxyapatite-coated stems versus uncoated stems. The aim of this study is to report the performance of an alumina-on-alumina bearing cementless total hip arthroplasty and to compare stems with a tapered design with and without hydroxyapatite coating. We prospectively analysed the results of cementless tapered femoral stems (40 hydroxyapatite-coated versus 22 uncoated stems), a metal-backed fibre mesh hydroxyapatite-coated socket and alumina-on-alumina pairing. Of 75 hips studied, 62 were available for follow-up (mean of 10.5 years after surgery). The average Harris hip score was 90. Only one hydroxyapatite-coated stem was revised for aseptic loosening. One instance of non-progressive osteolysis was detected around a screw of a cup. All other components showed radiographic signs of stable ingrowth. Hydroxyapatite coating of the stem had no significant impact on the clinical or radiological results. Total hip arthroplasty with the presented implant and pairing provides a durable standard for all patients requiring hip joint replacement against which all newer generations of cementless implants should be judged.