Bipolar versus total hip arthroplasty for hip osteonecrosis in the same patient

Treatment of aseptic osteonecrosis of the femoral head: Historical aspects

The treatment of aseptic osteonecrosis (ON) of the femoral head has been the subject of numerous therapeutic and surgical proposals due to the absence of medical treatment with proven efficacy. For many years, the goal of surgical treatment was to avoid total hip replacement (THR) with uncertain survival in patients considered too young (30-50 years) for this procedure. Numerous conservative treatments were thus proposed: core decompression with numerous variants, non-vascularized and vascularized bone grafts, intertrochanteric and rotational transtrochanteric osteotomies, cementing. The lack of a common classification and a lack of knowledge of natural history complicated the interpretation of the results for a long time. Nevertheless, it appeared that these treatments were effective only in the very early stages and among these in the limited ONs, medial rather than central and especially lateral, with discrepancies according to etiologies apart from sickle cell disease recognized by all as being pejorative. For the same reason, partial arthroplasties have been attempted and abandoned in turn: femoral head total and partial resurfacing and femoral prosthesis. The most recent advances are stem-cell-enhanced core decompression and progress in total arthroplasty, whose reliability has made it possible to extend the indications to increasingly younger patients seeking treatment with guaranteed or near-guaranteed efficacy. Most of the other interventions have disappeared or almost disappeared because of their lack of effectiveness especially in extensive and post-fracture ONs, sometimes because of their complexity and the length of their post-operative management, and also because they complicate and penalize a future total arthroplasty. This argues for early detection of ON at an early stage where the "head can be saved" by stem cell augmented core decompression, a minimally invasive treatment that leaves the chances of success of a THR intact.

Radiographic evaluation of linear wear of bipolar hemiarthroplasty devices in vivo

BACKGROUND

The indications for bipolar hemiarthroplasty (BHA) have been narrowing as those for total hip arthroplasty (THA) have been expanding in cases of femoral neck fracture and initial stages of osteonecrosis of femoral head (ONFH). It is difficult to measure wear in vivo after BHA because the equipment used has a dual bearing system with an inner head inside a metal outer cup. The present study aimed to (1) use a roentgenograph to measure linear wear in vivo after BHA with different acetabular conditions around the bipolar cup, and (2) compare the linear wear of polyethylene between integral bipolar cup (IBC) and Centrax prostheses.

METHODS

From among patients who had undergone BHA in our department after 1996, we analyzed 48 joints with osteoarthritis (OA) and without acetabular cartilage, as well as 25 joints with ONFH of stage 3 or less, in which the acetabular cartilage remains. Two types of bipolar cup prostheses were used: the IBC, which was gamma-sterilized in air using 2-Mrad irradiation, and the Centrax, which was gamma-sterilized in nitrogen using 3-Mrad irradiation. To image the inner head in vivo, we used high-pressure X-ray photography; we measured linear wear of the polyethylene with software using Martell Method 1.

RESULTS

Comparing mean annual linear wear between the OA and ONFH groups, using IBC prostheses in both groups, there was a significant difference (0.213 mm vs. 0.096 mm, respectively; P = 0.0177). There was a significant difference between the Centrax and IBC prostheses in OA patients in terms of linear wear (0.04 mm vs. 0.213 mm; P = 0.0181).

CONCLUSION

The linear wear of polyethylene in BHA implants can be affected by the material used to manufacture the bipolar cup. Such implants should only be used for appropriate indications.

Clinical results of hemiarthroplasty using new bipolar cups for stage 3 or lower osteonecrosis of the femoral head: a retrospective study

PURPOSE

The aim of this study was to evaluate clinical and radiographic findings of stage 3 or lower osteonecrosis of the femoral head (ONFH) with intact acetabular cartilage in patients treated with bipolar hemiarthroplasty (BHA).

METHODS

A total of 79 hips that underwent BHA for ONFH were included in this study. The average observation period was 7.6 years. Clinical results were evaluated using the Harris hip score. We performed radiographic analysis to assess the migration of the outer cup, the permanent image around the outer cup, and loosening of the stem.

RESULTS

The total Harris hip score improved from 50 points before surgery to 92 points at final follow-up, while pain improved from 14 points to 36 points. Flexion improved from 94° to 120° and abduction from 27° to 37°. One patient on dialysis showed progress in terms of inward migration, and revision surgery was performed on the patient 14 years after the original surgery.

CONCLUSIONS

Midterm performance of BHA for stage 3 or lower ONFH at our hospital was good.

Relationship between pull-out strength and oscillation angle in bipolar cups: an in vitro study

PURPOSE

To compare the past and present bipolar hip arthroplasty (BHA) models in terms of balance between pull-out strength and oscillation angle (OA).

METHODS

The pull-out strength and OA of 8 BHA models were compared: UPF-II, IBC, and Tandem XLPE (Smith & Nephew); Ringloc x (Biomet); J-FX (DePuy); Bipolar (Nakashima Medical); Multipolar (Zimmer); and Centrax (Stryker).

RESULTS

Respectively for the UPF-II, IBC, Tandem, Ringloc, J-FX, Nakashima Bipolar, Multipolar, and Centrax, the mean pull-out strength was 2219 N, 3303 N, 1503 N, 951 N, 1453 N, 1856 N, 1536 N, and 753 N, whereas the mean OA was 54.2°, 53.8°, 64.0°, 73.2°, 63.0°, 65.4°, 55.6°, and 75.4°. The OA was lower in the integrated types. For pull-out strength of the locking mechanism, the integrated type (IBC and Nakashima) was stronger than the metal or polyethylene ring-lock type (all others). The pull-out strength and OA were negatively correlated (r= -0.881, p=0.007), and the balance between the 2 varied for different models.

CONCLUSION

There is a trade-off between the pullout strength and OA; optimal balance between the 2 should be based on each patient's need.

Hip arthroplasty for treatment of advanced osteonecrosis: comprehensive review of implant options, outcomes and complications

Surgical treatment for late stage (post-collapse) osteonecrosis of the femoral head is controversial. In these situations, the outcome of joint preservation procedures is poor. There are several arthroplasty options for late-stage disease. The clinical outcomes of hemiarthroplasty and hemiresurfacing are unpredictable because of progressive acetabular cartilage degeneration. Total hip resurfacing may be associated with further vascular insult to the femoral head and early failure of the implant. Total hip replacement with metal-on-conventional polyethylene bearing surfaces has been the gold standard, but implant survivorship is limited in young active patients due to wear and osteolysis. Newer alternative bearing surfaces may have improved wear characteristics, but their durability must be confirmed in longer-term studies.

S3-Guideline non-traumatic adult femoral head necrosis

INTRODUCTION

The treatment of adult non-traumatic avascular necrosis of the femoral head (AVN; N-ANFH) within an estimated incidence of 5000-7000 cases per annum in Germany remains a challenge. Risk factors include steroids, alcohol abuse, chemotherapy and immunosuppressive medication, but a genetic predisposition has been suggested. Early diagnosis of this often bilateral disease process is essential for successful conservative or joint preserving surgical management. In this review, we present the update German consensus S3 guideline "diagnosis and management for N-ANFH" as a concise summary.

MATERIALS AND METHODS

This systematic review is based on the published literature from January 1, 1970 to April 31, 2013 (German and English language). Inclusion criteria were systematic reviews, meta-analyses and relevant peer review publications. We identified a total of 3715 related publications, of which 422 were suitable according to the SIGN criteria, but only 159 fulfilled our inclusion criteria.

RESULTS AND CONCLUSIONS

Clinical suspicion of N-ANFH mandates radiographic evaluation. If radiographs are normal MRI scans are recommended, which should be evaluated according to the ARCO-classification. Differential diagnoses include transient osteoporosis, bone bruise, insufficiency fracture and destructive arthropathy. Untreated, subchondral fractures commonly occur within 2 years, during which the risk for contralateral involvement is high-thereafter unlikely. Conservative management with Ilomedin and Alendronat can be tried, but other pharmacological or physical treatments are inappropriate. No specific joint preserving procedure can be recommended, but core decompression should be considered in early stages if necrosis is <30 %. In ARCO stages IIIc or IV total hip arthroplasty (THA) should be contemplated, which offers similar outcome compared to osteoarthritis. Young age is the main risk factor for higher revision rates after THA for N-ANFH.

Is Hemiresurfacing Arthroplasty for Osteonecrosis of the Hip a Viable Solution?

We conducted a systematic review of published studies that evaluated the outcomes of hemiresurfacing arthroplasty (HRA) in patients with osteonecrosis (ON). A structured literature review of multiple databases referenced articles from 1950 to 2014. A total of 430 patients from 14 published studies were identified. The mean duration of follow-up after the HRA was 69 months. At the final follow-up, the mean postoperative Harris hip score was 85. Overall clinical success rate was 74%. A total of 102 (21%) revision surgeries were required after the index procedure. Our study has helped to further elucidate the outcomes of HRA in patients with ON. We believe that HRA in young, active patients is a viable option providing symptomatic relief and functional improvement.

Management of femoral head osteonecrosis: Current concepts

Osteonecrosis of femoral head (ONFH) is a disabling condition of young individuals with ill-defined etiology and pathogenesis. Remains untreated, about 70-80% of the patients progress to secondary hip arthritis. Both operative and nonoperative treatments have been described with variable success rate. Early diagnosis and treatment is the key for success in preserving the hip joint. Once femoral head collapses (>2 mm) or if there is secondary degeneration, hip conservation procedures become ineffective and arthroplasty remains the only better option. We reviewed 157 studies that evaluate different treatment modalities of ONFH and then a final consensus on treatment was made.

Bipolar hip arthroplasty for avascular necrosis of femoral head in young adults

BACKGROUND

Bipolar hip arthroplasty (BHA) is one of the options for treatment of avascular necrosis (AVN) of the femoral head. Acetabular erosion and groin pain are the most allowing for gross motion between the common complications. We propose that these complications are secondary to improper acetabular preparation allowing for motion between the BHA head and the acetabulum.

MATERIALS AND METHODS

The current study retrospectively evaluated patients'records from case files and also called them for clinical and radiological followup. 96 hips with AVN of the femoral head treated with BHA were included in the study. All patients were males with a mean age of 42 years (range 30-59 years). In all cases, the acetabulum was gently reamed till it became uniformly concentric to achieve tight fitting trial cup. Clinical followup using Harris hip score (HHS) and radiological study for cup migration were done at followup.

RESULTS

The mean followup was 7.52 years (range 4-16 years). The HHS significantly improved from a preoperative value of 39.3 (range, 54-30) to a postoperative value of 89.12 (range 74-96). According to HHS grades, the final outcome was excellent in 52 hips, good in 28 and fair in 16 hips. Hip and groin pain was reported in four hips (5%), but did not limit activity. Subsidence (less than 5 mm) of the femoral component was seen in 8 cases. Subgroup analysis showed patients with Ficat Stage 3 having better range of motion, but similar HHS as compared to Ficat Stage 4 patients.

CONCLUSION

Bipolar hip arthroplasty (BHA) using tight fitting cup and acetabular reaming in AVN hip has a low incidence of groin pain, acetabular erosion and revision in midterm followup. Good outcome and mid term survival can be achieved irrespective of the Ficat Stage.

A seven- to 14-year follow-up study of bipolar hip arthroplasty in the treatment of osteonecrosis of the femoral head

INTRODUCTION

Bipolar hip arthroplasty (BHA) in the treatment of Ficat stage III osteonecrosis of the femoral head (ONFH) has theoretical advantages over total hip replacement (THR) in that it preserves the natural acetabulum and uses an implant that allows better stability and larger range of movement. The purpose of this study was to evaluate the clinical and radiological outcomes of BHA with uncemented ingrowth stems in the treatment of ONFH.

MATERIAL AND METHODS

Thirty-nine hips in 34 patients (two women and 32 men) with a mean age at the time of surgery of 45.31 years (range 30-66 years) operated between 1998 and 2005 were examined in a retrospective evaluation. Mean follow-up was 9.5 years (range 3-14 years). Patients were evaluated with the Harris hip score (HHS). Kaplan-Meier survivorship was calculated to examine the revision rate. Radiographic analysis included evaluation of bipolar head migration, radiolucent lines around the stem and osteolysis in the acetabulum and the femur.

RESULTS

Evaluation of clinical results revealed an increase in HHS from 28 points preoperatively to 88.6 points at the most recent follow-up. Radiographic evaluation showed bipolar head migration in 3 hips (7.7%). Survival rate of BHA, with revision THR defined as the endpoint, was 92.31% at ten years (CI 95%). All implanted uncemented stems were stable without any radiographic signs of loosening or osteolysis.

CONCLUSIONS

The results of the present study show that implantation of BHA with uncemented ingrowth stem in Ficat stage III is still justified.

Arthroplasty in Femoral Head Osteonecrosis

Osteonecrosis of the femoral head is a destructive joint disease requiring early hip arthroplasty. The polyethylene-metal design using a 22-mm femoral head component, introduced by Charnley in 1950, has been widely used for over half a century. Since then, different materials with the capacity to minimize friction between bearing surfaces and various cement or cementless insert fixations have been developed. Although the outcome of second and third generation designs using better bearing materials and technologies has been favorable, less favorable results are seen with total hip arthroplasty in young patients with osteonecrosis. Selection of appropriate materials for hip arthroplasty is important for any potential revisions that might become inevitable due to the limited durability of a prosthetic hip joint. Alternative hip arthroplasties, which include hemiresurfacing arthroplasty and bipolar hemiarthroplasty, have not been found to have acceptable outcomes. Metal-on-metal resurfacing has recently been suggested as a feasible option for young patients with extra physical demands; however, concerns about complications such as hypersensitivity reaction or pseudotumor formation on metal bearings have emerged. To ensure successful long-term outcomes in hip arthroplasty, factors such as insert stabilization and surfaces with less friction are essential. Understanding these aspects in arthroplasty is important to selection of proper materials and to making appropriate decisions for patients with osteonecrosis of the femoral head.

Comparative Outcomes Assessment: Hip Hemiarthroplasty as an Alternative to THA in Patients with Surgically Pristine Acetabulum-Is There Still a Role?

This is a retrospective review of 243 hip arthroplasties treated with either hemiarthroplasty (61 surgeries-Group 1) or total hip arthroplasty (182 surgeries-Group 2). The mid- to long-term results of relatively similar, predominately young patient cohorts were assessed annually via radiographs and the Harris Hip Scores for pain and clinical function. Groin pain persisted in 16.4% of Group 1 and 5.5% of Group 2 (P = 0.0159). Thigh pain persisted in 11.5% of Group 1 and 2.2% of Group 2 (P = 0.0078). Complications in Group 1 were 4/61 including 2 revisions with an overall survival rate of 96.7% versus Group 2 complication rate of 29/182 with 15 revisions and an overall survival rate of 91.8%. There were no cases of acetabular protrusio in Group 1, but 2 cases (1%) in Group 2 had cup loosening or osteolysis. Two cases were revised in Group 1 (3.2%). Both were undersized femoral stems. The fifteen revisions (8.2%) in Group 2 included loose stem (1), instability (8), infections (3), cup loosening (2), and accelerated polyethylene wear (1). Hemiarthroplasty has a higher incidence of thigh and groin pain but fewer complications compared with total hip arthroplasty.

Evaluation of bipolar hemiarthroplasty for the treatment of steroid-induced osteonecrosis of the femoral head

PURPOSE

Bipolar hemiarthroplasty (BHA) for idiopathic osteonecrosis of the femoral head (ONFH) is performed at our institution. The purpose of this study was to evaluate the clinical and radiographic findings after BHA for the treatment of steroid -induced ONFH.

METHODS

Thirty-seven hips in 27 patients were assessed (seven men, 11 hips; 20 women, 26 hips), average patient age at the time of surgery of 42.6 (range 20-83) years, with steroid-induced ONFH treated with BHA between 1995 and 2005. The mean follow-up duration was approximately ten (range five to 15) years. Patients were evaluated according to the Japan Orthopaedic Association (JOA) hip score. Kaplan-Meier survivorship was calculated to examine revision arthroplasty failure rate. Radiographic analysis of loosening included radiolucent lines and osteolysis of the acetabulum or femur. Causes of loosening were analysed using multiple logistic regression.

RESULT

JOA hip score increased from 53 points (preoperative) to 87 points (final follow-up). Survival rates were 96.8 % and 78.6 % at ten and 15 years, respectively. Prosthesis loosening occurred on the acetabular side in five hips (13.5 %). No femoral-component loosening was observed. BHA had poor results in patients with Association Research Circulation Osseous (ARCO) stage IV ONFH and in patients under 40 years of age.

CONCLUSION

BHA, with strict surgical indications, may be a good option for treating ONFH. Based on these results, total hip arthroplasty is recommended for patients with ARCO stage IV ONFH or for patients under 40 years of age.

Total Hip Replacement in Avascular Necrosis of Femoral Head

BACKGROUND

A study was conducted to evaluate the role of total hip replacement in cases of advanced avascular necrosis of the head of femur in patients admitted to two tertiary care military hospitals. 20 patients reporting with avascular necrosis of femoral head were taken for study.

METHODS

Out of 20 patients, 16 were males and 4 were females. In 7 cases there was history of chronic alcohol intake and among them one patient was on steroids for long time for the treatment of bronchial asthma. 2 patients developed avascular necrosis of the femoral head following pregnancy and in two cases, it was post-traumatic. In the remaining nine cases, no cause was found and were so considered idiopathic. They were evaluated pre-operatively and total hip replacement was done in all twenty cases.

RESULTS

Patients were evaluated using Harris hip score. There was improvement of the score in all cases.

CONCLUSION

Total hip replacement is a boon for patients of advanced avascular necrosis of femoral head.

Osteonecrosis is not a predictor of poor outcomes in primary total hip arthroplasty: a systematic literature review

The primary goals of this critical literature review were to determine whether revision rates of primary total hip arthroplasty in patients with osteonecrosis differ based on the underlying associated risk factors and diagnoses, whether the outcomes of this procedure have improved over the past two decades, and to compare outcomes based on study level of evidence. A systematic literature review yielded 67 reports representing 3,277 hips in 2,593 patients who had a total hip arthroplasty for osteonecrosis of the femoral head. Stratification of outcomes by associated risk factors or diagnoses revealed significantly lower revision rates in patients with idiopathic disease, systemic lupus erythematosus, and after heart transplant, and significantly higher rates in patients with sickle cell disease, Gaucher disease, or after renal failure and/or transplant. There was a significant decrease in revision rates between patients operated upon before 1990 versus those in 1990 or later, with rates of 17% and 3%, respectively. The results for arthroplasties performed in 1990 or later were similar to those for all hips in publicly reported national joint registries. Certain risk factors were associated with higher revision rates in patients with osteonecrosis who were treated by total hip arthroplasty. However, most patients (82%) do not have these associated negative risk factors. Overall, this critical literature review provides evidence that osteonecrosis itself, or when associated with the most common risk factors and/or diagnoses, is not associated with poor outcomes in total hip arthroplasty.

SAS weekly rounds: avascular necrosis

Osteonecrosis of the femoral head is a condition that affects upwards of 10,000 individuals in the USA each year. The peak incidence is in the fourth decade of life, and overall, there is a male preponderance. The condition accounts for up to 12% of total hip arthroplasties performed in developed countries. The etiology can be traumatic or non-traumatic, with 90% of atraumatic cases attributed to corticosteroid therapy or excess alcohol consumption. Osteonecrosis of the femoral head reflects the final common pathway of a range of insults to the blood supply and ultimately results in femoral head collapse, acetabular involvement, and secondary osteoarthritis. Currently, conservative treatment options, which aim to correct pathophysiologic features allowing revascularization and new bone formation, appear to be able to delay but not halt the progression of this condition. As a consequence of femoral head osteonecrosis, many individuals undergo surgical treatments including: core decompression, osteotomy, non-vascularized bone matrix grafting, free vascularized fibular grafts, limited femoral resurfacing, total hip resurfacing, and total hip arthroplasty.

Pyrolytic carbon endoprosthetic replacement for osteonecrosis and femoral fracture of the hip: a pilot study

Hemiarthroplasty in young patients has the potential for eliminating bearing wear, but has the disadvantage of cartilage wear. Low-temperature isotropic (LTI) pyrolytic carbon reportedly reduces cartilage wear in canine hemiarthroplasties. We therefore initiated a study in humans when it was released for human use. However, we observed failures in some patients. We therefore document and report the high failure rate observed in a subset of patients treated with an LTI pyrolytic carbon femoral head for osteonecrosis. We conducted a prospective pilot study of 17 patients treated with a titanium stem and an LTI pyrolytic carbon femoral head bearing surface for unipolar hemiarthroplasty for either femoral neck fracture (10 patients) or osteonecrosis (seven patients). One of 10 patients in the fracture group underwent conversion to THA as a result of arthritic progression compared with six of seven patients with osteonecrosis who underwent conversion to THA as a result of acetabular wear and severe groin pain. In this small series, patients with osteonecrosis had a higher rate of revision compared with the patients treated for femoral neck fracture.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Fluoroscopy cannot recognize intraoperative fracture in patients receiving 2-incision total hip arthroplasty

Intraoperative fluoroscopy is suggested as a standard procedure in 2-incision total hip arthroplasty. Between September 2003 and July 2004, 2-incision total hip arthroplasties were done in 18 hips with and another 18 hips without the use of fluoroscopy. In group 1, the anterior skin incision was initially limited to 5 cm. Fracture or instability was checked by fluoroscopy first and then the incision was enlarged to 8 cm for visualization. In group 2, incisions were made long enough to expose the surgical field. There were 2 femoral neck fractures in the fluoroscopy group. The fractures were linear in the anteromedial femoral neck and could not be detected by fluoroscopy. Such linear fractures if overlooked could result in serious complications such as fracture displacement or implant instability. Surgeons should not rely on intraoperative fluoroscopy to check implant stability, and visualization of the surgical field should not be compromised when doing minimally invasive approach for total hip arthroplasty.

Acetabular diameter measurement determines proper prosthetic head size in hemiarthroplasty for femoral head osteonecrosis

In hemiarthroplasty for femoral head osteonecrosis, collapse and deformity may make femoral head measurement difficult, thus, precluding the selection of an appropriate prosthetic head. We describe a method for measuring the acetabular diameter using acetabular sizing gauges to estimate the prosthetic head size. We evaluated the precision of this method and found it to be highly accurate and reliable.

Managing femoral head osteonecrosis in patients with sickle cell disease

With an increasing number of people immigrating between different countries, sickle cell disease (SCD) is spreading all over the world. Due to improved health care, the life span of SCD patients has increased and many of them live to adulthood and middle-age. Osteonecrosis of the femoral head is one of the most common musculo-skeletal problems in SCD patients. Once osteonecrosis starts in the femoral head, it can progress from early to late stages in just a few years. Managing osteonecrosis of the femoral head in young-adults is a challenging problem and, in many situations, it requires major surgical procedures. In the early stages of the disease it is advisable to treat it by femoral head preserving procedures. In advanced stages, hip replacement arthroplasty (HPA) is indicated. In SCD patients, the incidence of operative complications and failure rates are higher than that for osteonecrosis due to other causes. Understanding the problems of SCD patients; appropriate diagnosis, prognosis, implications of the procedure performed and taking the necessary precautions, can reduce the complications and delay the failure of surgical procedures.

[Surgical treatment concepts for femoral head necrosis]

Osteonecrosis of the femoral head eventually leads to the destruction of the femoral head, if it remains untreated. Depending on the localization and the extent of the osteonecrosis several surgical treatment options can be considered. For early small and medium-sized pre-collapse lesions, core decompression is the treatment of choice. Osteotomies and bone grafting procedures can be utilized in medium pre-collapse, as well as in small post-collapse lesions. Cartilage lesions of the femoral head allow limited femoral resurfacing arthroplasty. If the acetabulum reveals cartilage lesions, a total hip replacement should be preformed.

Bipolar proximal femoral replacement prostheses for musculoskeletal neoplasms

While bipolar proximal femoral replacement prostheses (PFRP) have become a common treatment for tumors of the proximal femur, long-term results are not specified in the literature. The objective was to determine the complication and revision rates of bipolar PFRP and compare them to historical controls of bipolar hemiarthroplasties for nontumor indications. Information was retrospectively collected on 62 patients who received bipolar PFRP with cemented diaphyseal stems for primary or metastatic disease of the proximal femur from 1981 to 2003. Mean followup was 5 years. Twelve of 62 (19%) bipolar PFRPs underwent revision. Aseptic loosening was the most common complication with six (10%) undergoing revision. None were converted to THA due to acetabular erosion. Three patients (5%) had problems with dislocation and three (5%) had deep infections. Mean MSTS functional rating was 71% of normal function. The limb salvage rate was 98% and the 5-year event-free prosthetic survival was 79%. Bipolar PFRPs were found to have higher revision, dislocation, and deep infection rates compared to bipolar hemiarthroplasty for nontumor indications, but a lower rate of conversion to THA due to acetabular erosion. Bipolar PFRPs have good long-term durability with some complications, but are able to preserve the limb and provide good function for patients.

Current practices of AAHKS members in the treatment of adult osteonecrosis of the femoral head

BACKGROUND

There is currently no standardized protocol for evaluating and treating osteonecrosis of the femoral head in adults in the United States. We sought to understand current treatment practices of a group of surgeons who commonly treat this disease to determine if there was agreement on some aspects of care.

METHODS

We designed a two-staged mixed-mode (mailed and faxed) sixteen-question self-administered descriptive survey questionnaire to be sent to all 753 active members of the American Association of Hip and Knee Surgeons (AAHKS). The survey design was based on Dillman's survey research methodology, and the questionnaire included hypothetical clinical scenarios based on the Steinberg classification system. The responses elucidated the opinions and treatment preferences of high-volume arthroplasty surgeons who treat adult patients with osteonecrosis of the femoral head.

RESULTS

Of the 753 active members of the AAHKS, 403 (54%) responded to the questionnaire. Total hip replacement was reported to be the most frequent intervention for treatment of postcollapse (Steinberg stage-IIIB, IVB, V, and VI) osteonecrosis; core decompression was reported to be the most commonly offered intervention for symptomatic, precollapse (Steinberg stage-IB and IIB) osteonecrosis. Less frequently offered treatments included nonoperative management, osteotomy, vascularized and non-vascularized bone-grafting, hemiarthroplasty, and arthrodesis.

CONCLUSIONS

The care of adults with osteonecrosis of the femoral head varies among American orthopaedic surgeons specializing in hip and knee surgery. A consensus may evolve with a continued concerted effort on the part of interested surgeons, but it will require randomized, controlled, prospective studies of treatment of each stage of the disease and collaborative multicenter studies.

LEVEL OF EVIDENCE

Therapeutic Level V.

The position of the bipolar cup reflects the direction of the hip contact force acting on it

We radiographically measured the bipolar cup position to analyze the direction of joint force acting on the bipolar cup. The abduction angle of the bipolar cup was measured in each radiograph taken immediately and at six 12 weeks and yearly after the operation. Radiographs in patients with weight bearing were also investigated. The results indicated that the abduction angle of the bipolar cup was 24.1 degrees +/- 11.2 degrees immediate postoperatively and was 16.2 degrees +/- 5.1 degrees at 6 weeks, 16.1 degrees +/- 5.1 degrees at 3 months, and 16.2 degrees +/- 5.1 degrees at 1 year. The cup abduction angles with weight bearing were not different from those without weight bearing and were 15.9 degrees +/- 4.9 degrees , 16.2 degrees +/- 4.4 degrees , and 16.1 degrees +/- 4.7 degrees on the supine, double-legged stance, and single-legged stance radiographs, respectively. Because the position of the bipolar cup reflects the direction of loads pivoting on it, the direction of the joint force in the frontal plane acting on the bipolar prosthesis is about 16 degrees to vertical.

Nontraumatic osteonecrosis of the femoral head: ten years later

The etiology of osteonecrosis of the hip may have a genetic basis. The interaction between certain risk factors and a genetic predisposition may determine whether this disease will develop in a particular individual. The rationale for use of joint-sparing procedures in the treatment of this disease is based on radiographic measurements and findings with other imaging modalities. Early diagnosis and intervention prior to collapse of the femoral head is key to a successful outcome of joint-preserving procedures. The results of joint-preserving procedures are less satisfactory than the results of total hip arthroplasty for femoral heads that have already collapsed. New pharmacological measures as well as the use of growth and differentiation factors for the prevention and treatment of this disease may eventually alter our treatment approach, but it is necessary to await results of clinical research with long-term follow-up of these patients.

Two-incision total hip replacement: Intra-operative fluoroscopy versus imageless navigation for cup placement

The purpose of this study was to describe the surgical technique and to investigate results of a modified two-incision total hip replacement using either intraoperative fluoroscopy or imageless navigation. Twenty-nine patients (30 hips) with a minimum follow-up of one year were enrolled in this study. The patients were evaluated at 3, 6, 12 weeks, 6 months, and 1-year. The functional recovery as represented by the Harris hip score and WOMAC scale were better in the fluoroscopy group of patients at the early postoperative stage (3 wks). Thereafter, both groups showed rapid recovery with no difference in scores. Injury to the lateral femoral cutaneous nerve was the most commonly seen complication and it occurred in 6 hips (fluoroscopy 2; imageless 4). The symptoms were transient and resolved in 6 months in all 6 cases. This study demonstrated that the role of intraoperative fluoroscopy could safely be replaced by an imageless navigation system for the MIS-2 THA.

Five- to fifteen-year clinical results and the radiographic evaluation of acetabular changes after bipolar hip arthroplasty for femoral head osteonecrosis

We have studied 36 hips in 30 patients with osteonecrosis of the femoral head who were treated with bipolar hip arthroplasty. Follow-up period was 5 to 15 (average 7.7) years. Five hips were revised. Hips were divided into 2 groups. Sixteen hips with Ficat stage II or III osteonecrosis were assigned into group I, and 15 hips with Ficat stage IV osteonecrosis were assigned into group II. There was no statistical difference between the clinical results of the 2 groups (P = .74). Radiographically, there was minimal migration in group I. There was a statistical significance in superior migration between subgroups with and without osteolysis in group II (P < .01). We emphasize that bipolar hip arthroplasty is indicated for Ficat stage II or III in osteonecrosis of the femoral head.

[Pain management in non-juvenile, aseptic osteonecrosis]

BACKGROUND

Adult aseptic osteonecrosis (ON) represents a clinical picture with unexplained etiology. Since curative treatment of this disease often succeeds only in the early stage, pain therapy plays an important role in the treatment process.

METHOD

We compared established and novel treatment options for ON as well as our own results after i.v. administration of the prostacyclin analogue iloprost with corresponding studies in the literature.

RESULTS

In addition to treatment with nonsteroidal antirheumatic agents and opioids, surgical "core decompression," vasoactive medications, and hyperbaric oxygenation are effective. Treatment with iloprost for 5 days resulted in highly significant pain reduction.

CONCLUSION

Symptomatic treatment is indicated in all stages of ON and curative treatment in stage I and early stage II. In cases of disease progression in the large joints, early endoprosthetic replacement is indicated to avoid secondary damage. In addition to employing vasoactive substances, a further curative treatment approach could be the use of mesenchymal stem cells.

Femoral head resurfacing for the treatment of osteonecrosis in the young patient

We reviewed the clinical and radiographic results of 29 consecutive femoral head resurfacing procedures in 28 patients with avascular necrosis done from February 1997 until April 2000. There were 18 males and 10 females with an average age of 31.6 years (range, 12-48 years). The average Harris hip score significantly improved from 48.1 points preoperatively to 79.3 points at last followup. At final followup, 17 patients (18 hips [62%]) reported feeling much better or better than they did before hemiresurfacing. The overall survivorship was 75.9% at 3 years. Eight hips (27.6%) were converted to a total hip arthroplasty (THA) at an average 18 months (range, 8-43 months) after resurfacing. The results of this study suggest that femoral head resurfacing in a young patient with ON can greatly improve symptoms. The majority of patients were satisfied with the procedure but outcomes are unpredictable with only 62.5% of patients reporting satisfaction and good pain relief at last followup. We continue to offer this procedure in young patients with large necrotic lesions with the understanding that this procedure provides somewhat unpredictable pain relief; however, hemiresurfacing avoids the negatives associated with a bearing surface.

Bipolar versus total hip arthroplasty in the treatment of avascular necrosis of the femoral head in young patients

The authors evaluate medium-term results of bipolar and total hip arthroplasty as a treatment for avascular necrosis of the femoral head. Between 1990 and 2000, 57 hips (45 patients) were treated with a bipolar (BHA: 37 hips) or total hip arthroplasty (THA: 20 hips) depending on the radiographic and macroscopic aspect of the acetabulum. At surgery, all patients were under 65 years of age (average: 45.09 years). All had the same cementless hydroxylapatite coated femoral stem inserted through an anterolateral approach. The BHA were followed during a mean of 4.49 years. One BHA was lost to follow-up. Seven out of 36 hips (19.44%) were considered failures: three due to a poor functional result (Harris Hip Score (HHS) <70) and four which needed conversion to THA for groin pain. Two hips were revised for periprosthetic fracture. Twenty BHA (55.56%) had a good or excellent result (HHSY80). The THA were followed for a mean of 4.32 years. One THA was lost to follow-up. Four out of 19 hips (21.05%) were considered as failures. Three due to a poor functional result (HHS<70) and one which needed cup revision for recurrent dislocation. Fifteen THA (78.95%) had a good or excellent functional result (HHSY80). BHA as a treatment of avascular necrosis of the femoral head in young patients preserves bone stock for later revisions and can lead to excellent results. But the outcome seems less predictable than after THA. Groin pain associated to BHA can be treated successfully with conversion to THA if necessary. (Hip International 2002; 2: 142-9).