Recently, monoblock cups have increased in popularity for hip resurfacing and large femoral head total hips. However, there have been no studies specifically evaluating the durability of this type of cup. The purpose of this study was to define the mid-term survivorship of cobalt-chrome alloy, monoblock acetabular components.

A retrospective radiographic review of 426 consecutive hip resurfacings using the ConserveÒPlus prosthesis was performed with specific attention to the acetabular component.

Radiographs were analyzed for cup position, the presence of radiolucencies, cup migration, bead shedding, osteolysis and stress remodeling of the pelvic bone. Kaplan-Meier (KM) survival estimates were calculated using revision for aseptic loosening of the acetabular component as the end point.

Average follow-up was 8.6 years (range 5.4 to 12.3). Mean abduction angle and anteversion angle were 46.6° (± 6.8°), and 21.6° (± 8.6°), respectively. Radiolucent gaps behind the cup from incomplete seating were visible in zone 2 in 16% of cases. These were typically 1 to 2 mm in size and radiographically filled in all but 2 cases. No cups with early lucencies went on to fail. Late radiolucencies developed in zone 1 in 8 cups (1.9%), in zone 2 in 8 cups (1.9%), and in zone 3 in 19 cups (4.5%). Radiolucencies in multiple zones were seen in 6 cups (1.4%).

Small amounts of socket migration (2mm or less) were suspected in 3 cups (0.7%) but each of these has remained stable. There were no cases of bead shedding. Small osteolytic lesions were suspected in 12 hips (2.8%). There were 2 revisions for aseptic loosening of the cup at 5 and 8 years, and one revision for protrusion of the cup through the medial wall 4 days after surgery.

Additionally, one cup at 9 years follow-up is believed to be loose but has yet to be revised. The KM survival estimate was 99.6% at 5 years (95% C.I. 98.4% to 99.9%) and 98.7% at 10 years (95% C.I. 94.5% to 99.7%).

In conclusion, this study demonstrates excellent mid-term survivorship of a cobaltchrome alloy monoblock acetabular component, which matches that of conventional titanium implants. Small early gaps seen behind the cup from incomplete seating do not appear to effect cup survivorship as long as a good peripheral press-fit is obtained. Osteolysis with this prosthesis is rare but does occur.

Eighty-three patients (ninety hips) with well-fixed cementless socket retained during revision of a femoral component were reviewed. At revision, 33% of patients had acetabular osteolysis and 52% were grafted. At mean follow-up 9.6 years (5.5 – 15.9) after femoral revision and 14.8 years (7.1–20.2) after primary arthroplasty, survivorship was 96.5% (95% CI, 91.5% to 100%) at five years and 81%(95% CI, 61% to 99%) at ten years after femoral revision. Revision of a cementless acetabular component solely on the basis of the duration that it was in vivo or whether a previous revision had been done does not appear to be warranted.

Removal a well fixed cementless acetabular component can result in an increased operative morbidity. Data that can be used to predict the long-term survival of retained well-fixed cementless acetabular components are therefore needed.

Retention of the well-fixed cementless acetabular component during femoral revision is a predictable technique.

Revision of a cementless acetabular component solely on the basis of the duration that it was in vivo or whether a previous revision had been done does not appear to be warranted.

Eighty-three consecutive patients (ninety hips) in whom a well-fixed cementless socket had been retained during revision of a femoral component were reviewed. Mean patient age was fifty-four. At the time of revision, 33% of the patients had acetabular osteolysis of which 52% were grafted. At a mean follow-up 9.6 years (5.5 – 15.9) after femoral revision and 14.8 years (7.1–20.2) after primary arthroplasty, 94.5% of the sockets remained in place. With any revision as end point, survivorship was 96.5%(95% CI, 91.5% to 100%) at five years and 81%(95% CI, 61% to 99%) at ten years after femoral revision. With failure of cementless socket as end point (i.e. loosening, deficient locking mechanism), survivorship was 100% (95% CI, 100%) and 94% (95% CI, 82%–100%) at five and ten years after femoral revision and 100% (95% CI, 100%) and 94% (95% CI, 82%–100%) at ten and fifteen years after primary arthroplasty. No cases showed recurrence or expansion of pelvic osteolysis. The overall incidence of dislocation was 15%.

Ninety-four hips with a mean patient age 34.2 (range 15– 40) with a metal/metal surface arthroplasty (SA) were reviewed with 71% men and 14% with previous surgery. The Chandler risk index was calculated as well as the SA risk index (SARI). At a mean follow-up three years, three hips were converted at a mean of twenty-seven months (two to fifty), and ten patients had significant radiological changes. Mean SARI for the thirteen problematic hips versus remaining hips was significantly higher, 4.7 and 2.6, respectively (p=0.00). If SARI > 3 the relative risk of early problems is twelve times greater than if SARI ≤3.

The purpose of this study was to evaluate the early outcome of a hybrid metal on metal surface arthroplasty of the hip in patients forty years and younger and identify potential risk factors.

Surface Arthroplasty Risk Index can help identify patients who may be at increased risk of early failure following metal on metal surface arthroplasty.

Proper patient selection and careful surgical technique may minimize early failures with the re-introduction of surface arthroplasty of the hip.

Ninety-four hips mean age 34.2 (range 15– 40) with metal/metal surface arthroplasty (SA) were reviewed with 71% men and 14% with previous surgery. The Chandler risk index was calculated and SA risk index (SARI). Mean follow-up three years (range 2–5), three hips were converted at a mean of twenty-seven months (2–50), and ten patients had significant radiological changes. Mean SARI for these thirteen problematic hips versus remaining hips was significantly higher, 4.7 and 2.6, respectively (p=0.00). The mean angle between the prosthesis stem and femoral shaft in the problematic group was significantly smaller than the remaining hips (p=0.03): 133° and 139°, respectively. If SARI > 3 the relative risk of early problems is twelve times greater than if SARI ≤3.

Thirty-seven hips in thirty-four patients, mean age forty-one, underwent surgical dislocation of the hip with chondro-osteoplasty for the treatment of femoroacetabular impingement. At a mean follow-up of 2.1 years (2.0–4.0), the pre & post-operative outcome scores were for the: WOMAC 59.2 to 81.0 (p< 0.001), UCLA Hip Scores for pain 4.2 to 7.6;walking 7.3 to 8.6;function 6.2 to 8.1;activity level 4.3 to 6.9 (p< 0.05); and SF-12 physical 37.4 to 48.0 (p< 0.003) & mental 46.0 to 51.6 (p< 0.01). No hips have undergone further reconstructive surgery. Complications: one failure of fixation of the trochanteric osteotomy and one excision of bilateral ectopic ossification. No cases of osteonecrosis.

The purpose of our study was to evaluate the early clinical results and quality of life outcome after chondro-osteoplasty of the femoral head/neck junction for the treatment of femoroacetabular impingement.

An offset correction by surgical dislocation of the hip joint is a safe and an effective procedure in the treatment of femoroacetabular impingement commonly associated with labral tears.

Femoro acetabular impingement is a due to an absence of concavity at the anterolateral head neck junction associated with labral pathology. At short-term followup correction of the bony abnormality has improved functional outcome both from a disease-specific and health-related standpoint.

Thirty-seven hips (eighteen males; sixteen females) with persistent hip pain mean age forty-one (twenty-four to fifty-two) underwent 3-Dimensional CT of the pelvis and MR Arthrography prior to undergoing surgical dislocation with chondro-osteoplasty of the femoral head/neck junction. Preoperatively, the mean alpha angle of Notzli was 65.6(range, 42.0–95). At a mean follow-up of 2.1 years (2.0–4.0), the pre & post-operative outcome scores were for the: WOMAC 59.2 to 81.0 (p< 0.001), UCLA Hip Scores for pain 4.2 to 7.6;walking 7.3 to 8.6;function 6.2 to 8.1;activity level 4.3 to 6.9 (p< 0.05); and SF-12 physical 37.4 to 48.0 (p< 0.003) & mental 46.0 to 51.6 (p< 0.01). No hips have undergone further reconstructive surgery. Complications: one failure of fixation of the trochanteric osteotomy and one excision of bilateral ectopic ossification. No cases of osteonecrosis. Nine hips had removal of painful internal fixation.

Fifty-six hips, mean age 40.4 underwent surface arthroplasty (SA) and twenty-eight hips, mean age 37.2 underwent hemiresurfacing (HSR). Diagnosis was osteo-necrosis in all. UCLA hip function and activity score, SF-12 physical, and Harris Hip score were significantly (p< 0.05) better for SA versus HSR. However, 2 SA were revised to THR, and 5 had evidence of femoral loosening. There was no evidence of femoral loosenings in the hemiresurfacing group. The median femoral component size was significantly larger in HSR than SA. Although the functional results are inferior with HSR, patients are at greater risk of femoral loosening with the full surface arthroplasty.

To determine if differences in outcome exist between HSR and MMSA at five years of follow-up in a group of patients with Ficat Stage III and IV osteonecrosis.

Treatment of osteonecrosis of the hip in the young adult still remains a challenge. The continued use of conservative prosthetic solutions should help minimize the morbidity of revision hip surgery.

Although the functional clinical outcome of MMSA is superior to HSR, patients are at greater risk of femoral loosening. Use of a larger femoral component in MMSA may decrease the risk of femoral loosening.

Eighty-four hips with osteonecrosis were treated with a resurfacing implant: fifty-six with a metal-metal SA, mean age 40.4 and twenty-eight, mean age 37.2 with a hemiresurfacing when the acetabular cartilage was minimally damaged. Male/female ratio was 73%/27% for HSR and 87%/13% for MMSA. Mean follow-up of 4.5 years, UCLA hip scores were significantly (p< 0.05) better for MMSA versus HSR for function (9.3 vs. 7.9) and activity (6.8 vs. 5.5) but not for pain (9.3 vs.8.6) and walking (9.5 vs. 9.0). SF-12 scores were comparable for the mental component but significantly better in the MMSA group (48.4 vs. 38.1, p= 0.001) for the physical component. Harris Hip Score was significantly better for MMSA (92.3 vs. 83.3, p=0.001). 2 MMSA were revised to THR, and five presented with evidence of femoral loosening. There was no evidence of femoral loosenings in HSR. Median femoral component size was significantly larger for HSR (50.0 vs. 46.0, p= 0.001).

Introduction and Aims: Legg-Calve-Perthes disease and slipped capital femoral epiphysis are hip disorders that may result in the alteration of proximal femoral anatomy and subsequent osteoarthritis. LCP often results in a flattened head and short femoral neck; SCFE residual deformity is a retroverted head upon a wide femoral neck. Because of the low head to neck ratio and short neck length in these patients, surface arthroplasty is especially technically difficult.

Method: We examined a cohort of patients with either LCP or SCFE who underwent surface replacement of the hip to assess clinical results and identify pre-operative radiographic factors unique to this group. All patients with arthritis of the hip secondary to either LCP or SCFE, who underwent surface replacement between 1996–2002, were included. Proximal femoral anatomy was assessed by measuring the neck and head length, flattening of the head, anterior head offset and lateral head offset. Hip ROM was measured and SF-12 and UCLA Hip scores were calculated.

Results: Fourteen patients with LCP and 11 patients with SCFE had undergone surface replacement with an average age of 38 years; the mean time to follow-up was 26.2 months. Pre-operative radiographs revealed a head-neck ratio of 1.3 in the LCP group and 1.2 in the SCFE group. The amount of head offset was 9.4mm anterior and 6.4mm lateral in the LCP group; and 8.8mm and 4.4mm in the SCFE group. Neck and head length was 42mm in the LCP patients and 56.5mm in the SCFE patients; this measured 46 and 53mm post-operatively. No revisions had been performed in either group. The UCLA scores, SF-12 scores, and hip ROM did not differ from a cohort of patients who had undergone resurfacing for other reasons. No femoral neck fractures occurred in either group.

Conclusion: Despite technically difficult surgeries for hip resurfacing in these patients because of a flattened head and short neck in LCP, and wide femoral neck with retroverted heads in SCFE, the results to date have been good. By taking extra care to avoid notching the neck on the anterior and lateral tension sides, satisfactory results can be achieved.

Introduction and Aims: The importance in assessing clinical outcome is critical in evaluation of total hip replacement. There is now a sufficient body of evidence that activity level is correlated to wear of total hip replacement and wear to the longevity of that implant. The purpose of this study was, using the UCLA activity scale, to evaluate how activity relates to both health-related and disease-specific questionnaires.

Method: One hundred and fifty-two patients who underwent primary hip arthroplasty filled out the health-related questionnaire – SF-12 survey, which has a mental and physical component – with an average score of 50 in the general population for each category. The same day they were clinically evaluated, using the UCLA and Harris hip scoring systems. All patients were evaluated by the same surgeon; at least two years post-surgery, with an average follow-up of 5.2 years. Patient average age at surgery was 52.4, with 66% male. To assess the strength of the relationship between SF-12, UCLA and Harris scores, linear regression analysis was used.

Results: All individual UCLA scores were significantly correlated (p< 0.05) to SF-12 physical component, except for walking. When the single item UCLA activity score was added to Harris hip score, R squared raised from 0.43 to 0.53 in predicting quality of life. The single item Activity from the UCLA scoring system explained 38% of the variability in SF-12 physical component. With the linear regression analysis, all individual UCLA scores were independently significantly correlated (p< 0.05) to SF-12 physical component, except for walking. When the single item UCLA activity score was added to Harris hip score, R squared raised from 0.43 to 0.53 in predicting quality of life represented by the physical component of the SF-12.

Conclusion: Our study has shown that the UCLA activity scale is not only important to assess wear of the bearing surface, but also provides additional information in assessing the clinical outcome of total hip replacement. The single item Activity from the UCLA scoring system explained 38% of the variability in SF-12 physical component and demonstrates the need to integrate activity in outcome measurements after hip arthroplasty.

Purpose: Treatment of Ficat stage III and IV femoral head necrosis is a major problem and a subject of debate because of the young age of the patients and the disappointing results obtained with total hip arthroplasty (THA). We present our experience with hybrid twin cups cemented on the femoral side and not cemented on the acetabular side using a metal-on-metal bearing to determine the mechanisms leading to revision and to assess mid-term outcomes.

Material and methods: Fifty-four hips with osteonecrosis were treated with the twin cup and studied at minimum two years follow-up. Mean patient age was 40.4 years (16–56), 13% of the patients were women and 87% men. The Ficat score (13% stage III, and 87% stage IV) was used. A prior operation had been performed in 33% of the hips.

Results: Mean follow-up was 4.4 years (2.1–6.8). Four hips required revision, three for femoral loosening after mean 46.3 months, and one for fracture of the acetabular wall immediately after the operation. The mean UCLA scores showed improvement: 3.3 to 9.3 for pain, 5.5 to 9.7 for walking, 5.0 to 9.4 for physical functioning, and 4.2 to 7.2 for activity. Physical and mental items on the SF-12 showed that normal quality-of-life was restored (compared with the general population in the United States).

Discussion: Although it is too early to speculate concerning the long-term outcome of these twin cups implanted in young patients with hip osteonecrosis, the clinical results have been encouraging. This prosthesis is an interesting alternative to the adjusted cup in the event of acetabular cartilage damage. If necessary, the acetabular component can be saved during conversion to THA without any deleterious clinical effects.

Purpose: The purpose of this work was to evaluate clinical and radiographic factors affecting early outcome of resurfaced hip prostheses in young adults.

Material and methods: Among 119 hybrid resurfaced prostheses with a metal-on-metal bearing implanted in patients aged 40 years or less, 94 were retained for analysis at minimum two years follow-up or failure. Mean age was 34.2 years (15–40), 71% of the patients were men and 14% had had a prior hip operation. A risk index (SARI) was developed from the Chandler index.

Results: Mean follow-up was three years (2–5). Items of the UCLA score improved: pain 3.1 versus 9.2, walking 5.8 versus 9.4 (p=0.00). Three hips required revision total hip arthroplasty at mean 27 months (2–50) and ten patients had radiographically significant modifications. Comparing these 17 hips with the 47 others, indexes showed 4.7 versus 2.6 for the SARI (p=0.000) and 2.6 versus 2.8 for the Chandler score (p=0.358). There was no correlation with reconstruction mechanics, function, walking or scoring. Valgus implantation of the femoral piece and the lateral lever arm were significantly correlated (r=0.39, p< 0.001).

Discussion: If the SARI was > 3, the relative risk of early complications was 12-fold higher than if the SARI was 3. Because of the distinct fixation of the femoral implant, a SARI=2 was attributed when there was a cyst in the femoral head and weight was < 82 kg (lower weight correlated with smaller implant, r=0.60). This index can be used to improve patient selection in order to define the role of arthroplasty resurfacing in the treatment of hip degeneration.

Purpose: Removing a non-cemented cup can increase operative morbidity destroying bone stock. Data are thus needed concerning the long-term behaviour of non-cemented acetabular implants left in place after revision of the femoral component of a total hip arthroplasty.

Methods: We studied clinical and radiological outcome at five and fifteen years in a consecutive series of 83 patients (88 hips) with a non-cemented acetabular implant that was left in place after revision of the femoral component of a total hip arthroplasty. Mean age of the patients at revision surgery was 54 years. Two types of acetabular implants had been used: 69 titanium screen and 19 with a porocoat surface. All revisions were performed for isolated loosening of the femoral component. At revision, 33% of the patients had an osteolytic acetabulum and 52% had a bone graft.

Results: At mean follow-up of 7.5 years after revision (acetabular implants in situ for 11.6 years on the average), the mean UCLA function scores, preoperatively and at last follow-up were, respectively, pain 3.8 versus 8.9, gait 6.3 versus 8.4; function 5.8 versus 7.9; activity 4.8 versus 6.1. Six acetabular implants required a revision procedure at 7.5 years (mean, range 2 – 14 years) after the femoral revision (acetabular implants in situ for 13.3 years on the average) or acetabular loosening (n=1), conversion to a metal-on-metal bearing (n=1), and for repeated dislocation and infection (n=1). There were no hips with recurrent or worsening osteolysis.

Discussion: The duration of implantation or prior revision would not appear to be sufficient to justify removing a non-cemented acetabular implant. Presence of osteolysis does not appear to affect long-term fixation of the non-cemented acetabular implant after femoral revision. We recommend removing the acetabular screw at revision in order to correctly assess the component’s fixation.