Aims

Adverse local tissue reactions associated with abnormal wear considerably slowed down the general use of metal-on-metal (MoM) hip resurfacing arthroplasty (HRA), now limited to a few specialized centres. In this study, we provide the clinical results of 400 consecutive MoM HRAs implanted more than 20 years ago in one such centre.

Background

Hip resurfacing arthoplasty (HRA) showed promising early and mid-terms results at the beginning of the new millennium. Adverse local tissue reactions associated with metal debris considerably slowed down the implantation of HRA which use is now limited to a few specialized centers. The long term success of this procedure, however, is still largely unknown. This study aimed to provide the clinical results of a series of 400 consecutive HRA with a minimum follow-up of 20 years.

Aims

In previous studies, we identified multiple factors influencing the survivorship of hip resurfacing arthroplasties (HRAs), such as initial anatomical conditions and surgical technique. In addition, the University of California, Los Angeles (UCLA) activity score presents a ceiling effect, so a better quantification of activity is important to determine which activities may be advisable or detrimental to the recovered patient. We aimed to determine the effect of specific groups of sporting activities on the survivorship free of aseptic failure of a large series of HRA.

Aims

This study presents the long-term survivorship, risk factors for prosthesis survival, and an assessment of the long-term effects of changes in surgical technique in a large series of patients treated by metal-on-metal (MoM) hip resurfacing arthroplasty (HRA).

Aims

A contact patch to rim (CPR) distance of < 10 mm has been associated with edge-loading and excessive wear. However, not all arthroplasties with a low CPR distance show problems with wear. Therefore, CPR distance may not be the only variable affecting the post-operative metal ion concentrations.

Aims

Hip resurfacing arthroplasty (HRA) is an alternative to conventional total hip arthroplasty for patients with osteonecrosis (ON) of the femoral head. Our aim was to report the long-term outcome of HRA, which is not currently known.

Obtaining fixation in DDH with Surface arthroplasty (SA) with a two part polyethylene (PE ) socket was technically challenging. Although dislocation was rare there was a high loosening rate secondary to polyethylene wear. The purpose of this study was to evaluate the results of Conserve Plus metal-on-metal SA in Crowe class I and II Developmental Dysplasia of the Hip patients.

54 patients (59 hips), 72% females, average age43.7 years (15 to 63.8) met these inclusion creteria with 2 years of follow-up minimum. Seven hips were Crowe type II and fifty-two were type I.

Harlan C. Amstutz, John Antoniades, Michel J. Le Duff, Paul E. Beaulé

The results of MMSA are much improved over those of prior generations of SA and socket fixation is stable even in Crowe type II with the porous coated acetabular components without adjuvant fixation despite incomplete acetabular coverage of the socket. The hips have-been stable even with important range of motion. Recent short term failure and radiolucencies have been eliminated by improved technique despite a high incidence of femoral cysts and reduced area of fixation.

The purpose of this study was to review our entire primary THR experience using large diameter femoral heads in order to prevent dislocation.

83 hips in 77 patients (average age 61years) had a total hip replacement using femoral heads at least 36 mm in diameter. Average follow-up was 4.4 years (range 1 to 17). 22% of the bearings used were conventional UHMWPE, 25% Metal on Metal (two thirds of which were one-piece sockets), and 53% cross-linked polyethylene.

UCLA hip scores improved significantly (p< 0.001) to 9.4, 8.4, 7.5, and 5.2, for pain, walking, function and activity respectively. All of the hips were stable at last follow-up although 3 hips had to be revised: 2 for instability in the early post-op period for poorly positioned socket and one for acetabular component aseptic loosening, which was rectified by revision surgery. Two out of these 3 hips had an etiology of DDH. The dislocations occurred in hips reconstructed with a head size less of 36mm only and none of the hips that dislocated had to be revised with a constrained acetabular liner.

As the safety of new wear-resistant joint bearings has improved, an increase of femoral head size leads to a lower prevalence of dislocation in THR potentially without adverse wear consequences. However, adequate positioning of the acetabular component remains a key factor in the success of this type of hip arthroplasty. Metal-on-metal, which provides the largest ball size for a given socket diameter, especially with a one-piece socket, best addresses component-to-component impingement by increasing the range of motion. Bone-to-bone impingement risks are also minimized as the travel distance to dislocation is increased by maximizing the head diameter and minimizing the socket shell thickness.

The purpose of the present study was to analyze the-clinical and radiographic factors which determine the enduring fixation of metal on metal hybrid surface arthroplasty.

The first 500 hips (in 436 patients) of a consecutive series of over 700 Conserve® plus were reviewed clinically and radiographically. The patients were 48.6 years-old in average, 74% were male and the dominant etiology was idiopathic osteoarthritis (64.6%). All femoral components were cemented but the femoral metaphyseal stem was cemented in 112 hips and press-fit in the remaining 388.

Average follow-up was 4.8 years (range, 2.7 to 7.8 years). Eighteen hips were converted to a THR, 11 of them for aseptic loosening of the femoral component at an average follow-up of 40.5 months. Put in positives mention fx and loose incidence, survor ship details of loose and fx for other At last review, 14 hips presented metaphyseal stem radiolucencies and 16 hips (3.2%) showed a narrowing of the neck of 10% or more at the interface with the femoral component. None of the components with cemented stems showed femoral radiolucencies, neck narrowing, or were revised for aseptic loosening. Cementing the femoral stem significantly (p = 0.013) reduces the chances of early femoral failure or appearance of a metaphyseal stem radiolucency.

Risk factors for loosening or radioluciences included cysts > 1 cm, small femoral head size, female gender, early cases (before improved acrylic fixation including femoral suctioning measures were instituted) and reduced stem shaft angle. Metal-on-metal surface arthroplasty provides a stable, bone conserving, low morbidity and wear resistant prosthetic solution well suited for young and highly active patients.

Because the femoral head/neck junction is preserved in hip resurfacing, patients may be at greater risk of impingement, leading to abnormal wear patterns and pain. We assessed femoral head/neck offset in 63 hips undergoing metal-on-metal hip resurfacing and in 56 hips presenting with non-arthritic pain secondary to femoroacetabular impingement. Most hips undergoing resurfacing (57%; 36) had an offset ratio ≤ 0.15 pre-operatively and required greater correction of offset at operation than the rest of the group. In the non-arthritic hips the mean offset ratio was 0.137 (0.04 to 0.23), with the offset ratio correlating negatively to an increasing α angle. An offset ratio ≤ 0.15 had a 9.5-fold increased relative risk of having an α angle ≥ 50.5°. Most hips undergoing resurfacing have an abnormal femoral head/neck offset, which is best assessed in the sagittal plane.

Aims: Review short to medium term results of a metal-on-metal (M/M) hybrid surface arthroplasty (SA) for a young and active patient population. Methods: The þrst 400 hips (of 533) in 355 patients underwent M/M hybrid surface arthroplasty. Mean age 48.2; 73% males, 27% females; 198 Charnley Class A; 139 Class B and 18 Class C. Diagnosis at surgery: OA 64%, DDH 11%, ON 9%, Post-traumatic 8%, Inßammatory arthritis 3%, SCFE and LCP 4%, Melorheostosis 0.3%. Results: Mean follow-up 3.9 years (2.6–6.5). Average UCLA hip scores post-op: pain 9.4, walking 9.5, function 9.4, and activity 7.7. The SF-12 physical and mental components were respectively, 31.2 and 46.8 pre-op and 50.1 and 53.0 post-op. 12 hips were converted to THA (8 in the þrst 102): 2 neck fractures, 7 femoral loosenings, 1 socket protrusio due to over-reaming, 1 subluxation due to impingement and 1 sepsis. Conclusions: Clinical results are excellent despite very high activity levels. The experience with SA of all cemented metal/UHMWPE bearing demonstrated failure rates of 15%–33% at 3 years. At longer follow-up, the preliminary experience is encouraging (3% failure rate). Dislocation is rare, and acetab-ular þxation secure. Initial femoral þxation is critical as the þxation area is small, especially with osteopenia and cystic degeneration. The percent of complications and potentially adverse radiographic changes was much greater in the þrst 100 cases, during the time of development of instrumentation, technique, and bearing optimization.

Aims: To review the medium term clinical and X-Ray results of DDH in SA, using the Conserve Plusª. Methods: 28 hips (26 patients, avg. age 43.2 years) with DDH were treated with hybrid MMSA. 81% were female. 42% had prior osteotomies. 25% had acetabular cysts that were grafted and 64% had femoral cysts (> 1cm in size) & 1 was grafted. A posterior approach was used in all but one case. Results: Mean F/U was 4.1 years (3.3– 6.5). UCLA hip scores were 3.3, 6.0, 5.7 and 4.5 pre-op and 9.2, 9.3, 9.3 and 7.1 at last F/U for pain, walking, function and activity. SF-12 scores normalized. Range of motion was 121.3û, 73.7û and 83.7û at last F/U for Flexion, abductionadduction, and rotation arcs. 2 hips were converted to THA: 1 for femoral neck fracture at 2 months (neck osteopenia and cystic degeneration) and 1 for recurrent subluxations due to poor offset and impingement due to prior multiple osteotomies. 4 technical complications successfully resolved: 1 trochanteric non-union, 1 post-op dislocation (closed reduction), 1 component mismatch (acetabular component exchange) and 1 femoral nerve palsy. X-ray analysis: 2 pts. presented complete radiolucencies around the metaphyseal stem and 1 patient was symptomatic and will require revision). Conclusions: SA is stable, except for 1 subluxation due to impingement with poor off-set compared to 7–10% with THA. The socket þxation is secure with grafts incorporating whereas prior SA with PE were poor due primarily to socket loosening. Femoral bone preparation is critical to avoid fractures and loosening.

Aims: The purpose of this study was to determine the success of retaining a well-þxed acetabular component at the time of isolated femoral revision and identify variables that may inßuence clinical decision making and outcome. Methods: 83 consecutive patients (90 hips) with a retained cementless socket during revision of a femoral component were reviewed. Eighty-þve percent of the hips were initially reconstructed as metal on polyethylene surface arthroplasty (SA) and 15% as a standard stem type total hip replacement (THR). Average age at the time of revision was 54. 33% of the patients had acetabular osteolysis of which 52% were grafted. Results: Mean follow up 9.6 years (5.5 to 15.9). Average time in situ of socket 14.8 years (7.1 to 20.2). 5 sockets were revised at a mean of 6.8 (2.5–10.4) years post revision and 13.1 years in situ. Reasons for socket revision were: 1 socket loosening, 1 dissociation of the liner cemented into the original socket, 1 instability, 1 conversion to a Metal/Metal bearing and 1 because it was the surgeonñs preference to remove the well-þxed socket. Dislocation rate was 15% with 50% occurring in the þrst 6 months post revision. Nine had more than one episode of dislocation. No recurrence or expansion of pelvic osteolysis was observed at last follow-up. Discussion: Revision of a cementless socket on the basis of the duration in vivo and/or presence of osteolysis does not appear to be warranted. Because of the high risk of dislocation off set liners/stems and larger femoral head sizes should be considered, especially in revision of SA.

Aims: To review the results and clinical performance of the Anthropometric Total Hip (ATH) with line to line broaching. Methods: 70 press þt titaniumalloy double-wedge taper (136 to 213 mm [mean, 187 mm]) extensively coated grit-blasted (RA=12.0μ) stem prostheses were implanted in 67 patients. There were 29 primary THA, 33 conversions of surface replacements, 6 revision THA and 2 conversions of Hemi-Surface Replacements. The mean age was 55.8 years (range, 20 to 77 years). There were 34 males and 33 females (3 bilateral). The initial etiology was OA (50%), ON (11%), DDH (23%), Post- Trauma (4%), SCFE (2%), Rheumatoid (2%), and Ç other È (8%).Results: The mean follow-up time was 4.7 years (Range: 2–8). UCLA hip scores improved for Pain, Walking, Function, and Activity from 4.8, 6.0, 5.5, and 4.5 pre-operatively to 9.2, 8.3, 7.9, and 5.9 post-operatively. ROM was also comparable to cemented THA results. There were no intra operative fractures. One patient had a bicycling accident, fractured his femoral shaft which healed without surgery. Solid biologic þxation (Ç osseointegration È) was achieved in 100% with the grit-blasted stem. Conclusions: This early investigation shows excellent clinical results, and none of the patients reported any thigh pain. Intra-operative fractures were eliminated with line to line broaching. Our results demonstrate that thigh pain with cementless THA can be essentially eliminated with a titanium-alloy stem and a gentle double-wedge taper geometry. Extensive Ç osseointegration È suggests potential for long term durability.