Surface replacement hemiarthroplasty for the treatment of osteonecrosis of the femoral head

Osteonecrosis

Younger patients are affected more often by osteonecrosis than by osteoarthritis, and osteonecrosis has significantly greater long-term morbidity.

Corticosteroids are the most common cause of nontraumatic osteonecrosis.

The femoral head is the most common site of osteonecrosis.

In rare instances, osteonecrosis of the jaw has been associated with bisphosphonate exposure. This phenomenon is more common with repeated intravenous infusions of bisphosphonates.

Case reports of osteonecrosis of the jaw in association with other medications, such as denosumab, have been reported.

The final common pathway in the pathogenesis of osteonecrosis is disruption of blood supply to a segment of bone.

Abnormalities in lipid metabolism, bone homeostasis, regulation of apoptosis, coagulopathies, innate immunity, and oxidative stress may play a role in the pathogenesis of osteonecrosis.

Epigenetics may alter the predisposition to develop osteonecrosis.

MRI is currently the optimal test for early diagnosis and identification of the extent of osteonecrosis.

Nonsurgical treatment of osteonecrosis does not change the natural history of the disease.

Although surgical treatment of femoral head osteonecrosis has many variations, most symptomatic patients eventually require total hip arthroplasty.

Knowledge of risk factors and early detection are crucial to the successful management of osteonecrosis.

Because of the lack of successful treatment options, new modes of management focus on the prevention of osteonecrosis.

Long-Term Effectiveness of Total Hip Replacement with the Collum Femoris Preserving Prosthesis

The objective of this study was to follow-up long term (5-12 years) patients with total hip arthroplasty with the collum femoris preserving prosthesis to evaluate clinical outcome and potential complications. Forty-six of 152 patients who underwent this procedure between September 2000 and September 2012 were followed up. The average follow-up time was 7.6 years, and assessed were radiographs, Harris score, limb length, hip function, and complications. Six patients had perioperative complications including five cases of femoral shaft fracture and one case of dislocation 1 week after the operation. No infections of the surgical site, no deep venous thrombosis or pulmonary embolism were observed. The last recorded Harris hip score improved from a preoperative average of 41.2 (range 17-60) to an average of 82.3 (74-96), with the score >80 in 38 patients, 70-80 in six patients, and <70 in two patients. Radiolucent lines were found on radiographs in two patients with acetabular prosthesis and one patient with femoral prosthesis. The remainder of patients had satisfactory positions of acetabular and femoral stem prostheses with no loosening or subsidence, and a good condition of femoral neck. Total hip arthroplasty with the collum femoris preserving prosthesis is a good option for younger patients who need prosthesis revision. This arthroplasty achieves satisfactory long-term effectiveness.

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.

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.

Treatment of femoral head osteonecrosis in the United States: 16-year analysis of the Nationwide Inpatient Sample

BACKGROUND

Many surgical interventions are used to treat osteonecrosis of the femoral head. The instance and distribution of these various procedures may give some insight into the practicing community's understanding of the efficacy of these treatments. We therefore sought to determine trends in the types and numbers of procedures performed for atraumatic osteonecrosis from 1992 through 2008 in the United States.

QUESTIONS/PURPOSES

(1) How has the overall incidence of surgical treatment for atraumatic osteonecrosis changed over this time period; and (2) how has the percentage of THA performed for osteonecrosis (compared with joint-preserving procedures) changed over this time period?

METHODS

The Nationwide Inpatient Sample database was used to collect information for all patients who had an International Classification of Diseases, 9(th) Revision diagnosis of hip osteonecrosis between 1992 and 2008. Procedures were collated according to frequency, and trends were analyzed for joint-preserving and joint-replacing procedures.

RESULTS

The total number of procedures performed over this time period for osteonecrosis of the hip increased from 3570 procedures to 6400 procedures per year. In 1992, 75% (n = 2678) of the procedures performed to treat osteonecrosis of the hip were THA, which increased to 88% (n = 5632) in 2008. The percentage of joint-preserving procedures consequently decreased from 25% to 12% over this period.

CONCLUSIONS

Previously, THA was believed to have poor survivorship and clinical results for the treatment of osteonecrosis of the hip, but reports since 1993 have suggested improved survivorship of these reconstructions. Our study suggests that surgeons have incorporated this into their practice patterns, in that an increasing percentage of patients with this diagnosis are treated with THA. Additionally, the total number of procedures performed for osteonecrosis has increased, which may reflect an improved awareness of this disease and more aggressive approaches to diagnosis and treatment.

Hip osteonecrosis: does prior hip surgery alter outcomes compared to an initial primary total hip arthroplasty?

The purpose of this study was to assess the clinical and radiographic outcomes of total hip arthroplasty (THA) in patients who had osteonecrosis to see if prior hip preserving surgery affected outcomes. Implant survivorship, Harris hip scores, and radiographic outcomes were compared between 87 patients (92 hips) who had undergone prior hip preserving procedures and 105 patients (121 hips) who had only undergone THA. Patients were also sub-stratified into low- and high-risk groups for osteonecrosis. At a mean follow-up of 75 months, there were no significant differences in survivorship, clinical, and radiographic outcomes among the cohorts. Higher revision rates were associated with patients who were in the high-risk group. The authors believe that hip joint preserving procedures may not adversely affect the outcomes of later THA in patients with osteonecrosis.

Osteonecrosis

Osteonecrosis affects younger patients more often than osteoarthritis and has significantly greater long-term morbidity.

Corticosteroids constitute the most common cause of nontraumatic osteonecrosis.

The femoral head is the most common site of osteonecrosis.

Bisphosphonate use is associated with osteonecrosis of the jaw.

The final common pathway in the pathogenesis of osteonecrosis is disruption of blood supply to a segment of bone.

Abnormalities in lipid metabolism, bone homeostasis, regulation of apoptosis, coagulopathies, and oxidative stress may play a role in the pathogenesis of osteonecrosis.

Magnetic resonance imaging is currently the optimal test for early diagnosis and identification of the extent of osteonecrosis.

Nonsurgical treatment of osteonecrosis does not change the natural history of the disease.

Although there are many variations on surgical treatment of femoral head osteonecrosis, most patients eventually require total hip arthroplasty.

Knowledge of risk factors and early detection are crucial to the successful management of osteonecrosis.

Due to the lack of successful treatment options, new modes focus on prevention of osteonecrosis.

Hemi-resurfacing versus total resurfacing for osteonecrosis of the femoral head

PURPOSE

To compare mid-term outcomes of hemi-resurfacing arthroplasty (HRA) and total resurfacing arthroplasty (TRA).

METHODS

Seven men and 5 women (16 hips) aged 33 to 72 (mean, 50) years underwent HRA, whereas 7 men and 3 women (16 hips) aged 23 to 52 (mean, 40) years underwent metal-on-metal TRA; all were for osteonecrosis of the femoral head. In the HRA and TRA groups respectively, 10 and 8 hips were steroid-induced, whereas 6 and 8 hips were related to alcohol abuse. Surgery for 12 and 4 hips entailed the posterolateral approach, whereas 4 and 12 hips entailed the Hardinge approach. Usually, HRA was performed for early stages of the disease, and TRA for more advanced stages. 12 and 6 hips were classified as JOA stages 1 to 3A, whereas 4 and 10 hips as stages 3B to 4. All the hips were JOA types C1 or C2.

RESULTS

In the HRA and TRA groups respectively, the mean follow-up period were 6.5 and 5.5 years. The mean total JOA hip scores were 57 and 54 preoperatively, 93 and 97 at one year, and 84 and 96 at the final follow-up (p<0.01). The higher score in the TRA patients was mainly attributed to improvement in the pain score. In the HRA group, 12 hips developed groin pain or groin discomfort while walking, though only 4 of them showed apparent joint-space narrowing. Five patients underwent revision surgeries (conversion to total hip arthroplasty) owing to a femoral neck fracture, acetabular protrusio, osteoarthritic change, and severe groin pain. Patients having TRA had no revision surgery and did not complain of groin pain. Implants in both groups were radiographically stable.

CONCLUSION

TRA were superior to HRA in terms of pain relief and implant survival, even though the former procedure was used for more advanced cases.

Femoral head osteonecrosis: why choose free vascularized fibula grafting

Osteonecrosis of the femoral head is a disease in which bone death occurs and usually progresses to articular incongruity and subsequent osteoarthritis. To delay the process of the disease and the conversion to total hip arthroplasty, many surgical techniques have been described. Core decompression, nonvascularized autologous bone grafts, porous tantalum implant procedure, and various osteotomies have been used for the management of early precollapse stage osteonecrosis of the femoral head. However, none of these procedures is neither entirely effective nor can obtain predictable results. With the progress of microsurgery, the implantation of a free vascularized fibula graft to the necrotic femoral head has provided the most consistently successful results. Although the procedure is technically demanding, there is growing recognition that the use of free vascularized fibula graft may improve patient quality of life by functional improvement and pain alleviation. The success of the procedure is related to decompression of the femoral head, excision of the necrotic bone, and addition of cancellous bone graft with osteoinductive and osteoconductive properties, which augments revascularization and neoosteogenesis of the femoral head. Free vascularized fibula graft, especially in younger patients, is a salvaging procedure of the necrotic femoral head in early precollapse stages. In postcollapse osteonecrosis, the procedure appears to delay the need for total hip arthroplasty in the majority of patients. The purpose of this review article is to update knowledge about treatment strategies in femoral head osteonecrosis and to compare free vascularized fibula grafting to traditional and new treatment modalities.

Development and Evaluation of Polyvinyl Alcohol-Hydrogels as an Artificial Atrticular Cartilage for Orthopedic Implants

Due to its excellent biocompatibility and mechanical properties, various different applications of polyvinyl alcohol-hydrogels (PVA-H) has been attempted in many fields. In the field of orthopedic surgery, we have been engaged for long time in research on the clinical applications of PVA-H as a artificial cartilage, and have performed many basic experiments on the mechanical properties, synthesis of PVA-H, and developed orthopedic implants using PVA-H. From these studies, many applications of artificial articular cartilage, intervertbral disc and artificial meniscus etc. have been developed. This review will present the overview of the applications and recent advances of PVA-H cartilages, and discuss clinical potential of PVA-H for orthopedics implant.

Surface replacement is comparable to primary total hip arthroplasty

Conversion of a failed surface hip replacement to a conventional total hip arthroplasty is reportedly a straightforward procedure with excellent results. We compared perioperative parameters, complications, and clinical as well as radiographic outcomes of 39 hemi and total hip resurfacing conversions with conventional THAs. The hips were matched by diagnosis, gender, age, body mass index, preoperative Harris hip score, and followup time to a cohort of primary conventional THAs performed during the same time period by the same surgeon. The mean operative time was longer (by 19 minutes) for the conversions, but other perioperative parameters were similar. At a mean followup of 45 months (range, 24-63 months), the mean Harris hip scores were similar in the two groups (92 points versus 94 points for the conversion and conventional hips, respectively). Thirty-eight of 39 stems were well-aligned and appeared osseointegrated. When a resurfaced hip fails, conversion to conventional THA has similar early clinical and radiographic outcomes to primary conventional THA.

LEVEL OF EVIDENCE

Level III, therapeutic (retrospective comparative study). See the Guidelines for Authors for a complete description of levels of evidence.

Femoral resurfacing in young patients with hematologic cancer and osteonecrosis

Resurfacing hemiarthroplasties were performed to treat advanced osteonecrosis of 20 femoral heads in 14 patients (median age, 19.8 years; range, 15.1-27.4 years), treated for hematologic cancer in childhood or adolescence. Seven hips in five patients were revised to total hip arthroplasties (THA) because of pain; three of these showed radiographic loosening of the femoral head resurfacing component. The median time from resurfacing to revision was 2.4 years (range, 0.9-4.8 years). Marginal Cox-regression analysis, adjusting for correlations owing to bilateral involvement, showed positive association of revision-free survival of the prosthesis with patient's age; time from resurfacing to the end of anticancer therapy, end of glucocorticosteroid therapy; percentage of joint space at the last radiograph; and size of the lesion has a negative association with revision-free survival. Because of this study's exploratory nature, p values were not adjusted for the number of statistical comparisons. Among 14 patients, the probability of not requiring resurfacing prosthesis revision was 66% (SE, +/-15%; 95% CI, 44%-100%) at 3 years. Osteonecrosis of the femoral head in young patients treated for hematologic cancer in childhood or adolescence poses a serious challenge to the orthopaedic surgeon. The data of this preliminary study suggest that in selected patients resurfacing hemiarthroplasty may delay the need for THA for 3-7 years.

LEVEL OF EVIDENCE

Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Thermal damage potential during hip resurfacing in osteonecrosis of the femoral head: an experimental study

Hip resurfacing arthroplasty has become an attractive treatment option for young, active patients with femoral head necrosis. However, little information is available about the potential thermal damage to the remaining femoral head when a cemented component is used. We used an experimental model to measure the temperature profile at the cement-bone interface during hip resurfacing. We compared four simulated lesion sizes-15, 25, 33, and 50%-of the femoral head, and a control group with no cystic lesion. Temperatures were measured with the specimens in a 37 degrees C saline bath or with copious pulsed lavage. With specimens tested in the bath, peak temperatures were higher, and durations of temperatures above 50 degrees C were longer, in femoral heads with necrotic lesions (88.8 +/- 7.5 degrees C; 17.6 +/- 1.1 min for a 15% lesion; 96.2 +/- 7.2 degrees C; 22.86 +/- 1.3 min for a 25% lesion; 99.7 (c) 200 +/- 9.4 degrees C; 28.6 +/- 2.0 min for a 33% lesion; and 97.2 +/- 4.2 degrees C; 35.6 +/- 2.4 min for a 50% lesion) than those in the control group (65.8 +/- 4.9 degrees C; 10.0 +/- 1.3 min). The larger the cement-filled cysts, the longer the temperatures remained above 50 degrees C. Although copious lavage reduced the temperature profile in each group, the temperatures remained above 50 degrees C for 7 to 17 min in specimens with necrotic cysts. The measured temperatures during surface replacement are sufficiently high in magnitude and long in duration to cause thermal damage to the remaining bone in femoral heads with preexisting necrotic lesions. Hip resurfacing for femoral head necrosis should be performed with caution.

Metal-on-metal hip resurfacing arthroplasty

The main advantage of hip resurfacing is bone conservation for patients likely to outlive a primary conventional hip replacement. Previous attempts at hip resurfacing failed predominantly because of the consequences of a high amount of wear of thin polyethylene acetabular components and poor femoral component fixation. With correct patient selection, surgeon education, and operative technique, survivorship at five years is comparable with that of traditional hip replacements. Hip resurfacing has its own unique set of complications, including a fractured neck of the femur. It is necessary to understand the risk factors prior to performing the procedure.

[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.

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.

Metal-on-metal hip resurfacing compares favorably with THA at 2 years followup

Metal-on-metal total hip resurfacing is a bone-conserving reconstructive option for patients with advanced articular damage. While intended to address several problems with conventional THA, the safety and efficacy is not well established. We therefore retrospectively compared the outcomes of 52 patients (57 hips) with resurfacing arthroplasty to 84 patients (93 hips) with cementless primary THAs. The patients had a minimum 2-year followup (mean 3 years). The patients with resurfacing arthroplasty had a mean age of 47 years (range, 22-64) while those with cementless primary THA had a mean age of 57 years (range, 17-92). After controlling for age, gender, and preoperative differences, the total Harris Hip Scores (HHS), function scores, and pain scores were similar between the two groups. However, the resurfacing group had higher activity scores (14 versus 13, p < 0.001) and range of motion (ROM) scores (5.0 versus 4.8, p < 0.001). The complication rates (5.3% for resurfacing versus 14.0% for THA) and reoperation rates (3.5% for resurfacing versus 4.3% for THA) were similar. The total hip arthroplasty and metal-on-metal resurfacing groups both showed improvement in HHS, pain, activity, and ROM and had similar early complication and reoperation rates.

Metal-on-metal hip resurfacing in osteonecrosis of the femoral head

BACKGROUND

The treatment of end-stage osteonecrosis of the femoral head remains a challenge to the orthopaedic surgeon. Historically, total hip arthroplasty for this condition has been associated with poor rates of survival and function when compared with total hip arthroplasty for the treatment of osteoarthritis. The purpose of this study was to determine the medium-term clinical and radiographic results of metal-on-metal hip resurfacing arthroplasty in patients with end-stage osteonecrosis of the femoral head.

METHODS

From June 1994 to March 2004, a consecutive single-surgeon series of seventy-three hip resurfacing procedures were performed in sixty patients for the treatment of end-stage osteonecrosis of the femoral head. The cohort included forty-two men (ten of whom had a bilateral resurfacing) and eighteen women (three of whom had a bilateral resurfacing). The mean age was forty-three years (range, seventeen to sixty-nine years). A clinical and radiographic review was performed.

RESULTS

There were four revision operations and one planned revision of the seventy-three hips during the follow-up period. Two of these revisions were necessitated by aseptic failure of the femoral component. This represents an overall survival rate of 93.2% at a mean of 6.1 years of follow-up (range, two to twelve years).

CONCLUSIONS

On the basis of this study, metal-on-metal resurfacing of the hip for osteonecrosis can be considered a safe and effective form of surgery for this group of patients. Longer-term follow-up is required to confirm the expected continued success of this form of arthroplasty in this difficult-to-treat population.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions to Authors on jbjs.org for a complete description of levels of evidence.

Systematic analysis of classification systems for osteonecrosis of the femoral head

BACKGROUND

Multiple classification systems for osteonecrosis of the hip have been developed to assist physicians in the diagnosis and treatment of this potentially debilitating disorder. The purpose of this analysis was to delineate the classification systems utilized in reports published since 1985 and, through a comparison of the most commonly used systems, to identify consistent factors that would allow for cross-publication comparisons to be made.

METHODS

We performed a PubMed search for reports of outcome studies concerning treatment methods for osteonecrosis of the hip. All studies of reported outcomes with greater than ten patients were included in the analysis. Various classification systems were tabulated to determine usage frequencies. The four most commonly used systems were then analyzed to determine common factors used for classification.

RESULTS

One hundred and fifty-seven studies were available for analysis. Sixteen major classification systems that made use of more than one radiographic factor were identified, and nine of these systems had one to five modifications reported throughout the literature. Additionally, eleven other systems made use of single factors obtained from either magnetic resonance imaging or anatomic data. The review revealed that four classification systems accounted for greater than 85.4% of the reported studies. Parameters for these four systems were stratified to allow for uniformity of patient or study evaluation.

CONCLUSIONS

This analysis of the reported classification systems for osteonecrosis of the femoral head revealed several similarities between the most commonly used systems. An analysis of patients can be made with any of the four major systems if specific data are collected according to various magnetic resonance imaging and radiographic findings. This approach will allow for easier comparison of studies across different centers.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions to Authors on jbjs.org for a complete description of levels of evidence.

Charnley-Kerboull total hip arthroplasty for osteonecrosis of the femoral head a minimal 10-year follow-up study

The purpose of this retrospective study was to report the minimum 10-year follow-up results of a consecutive series of 122 cemented low-friction total hip arthroplasties performed for osteonecrosis. Revision was performed for high polyethylene wear associated with periprosthetic osteolysis and socket loosening in 6 hips, and for deep sepsis in 1. The survival rate at 15 years, using revision for any reason as the end point, was 88.5%. Among the variables studied in this series, the only factor associated with a higher risk of revision was a socket wear rate greater than 0.1 mm/y. This series indicated that cemented low-friction total hip arthroplasty performed for avascular necrosis could grant satisfactory long-term results, provided that polyethylene socket wear remained below 0.1 mm/y.

The Stability of the Femoral Component of a Minimal Invasive Total Hip Replacement System

In this study, the initial stability of the femoral component of a minimal invasive total hip replacement was biomechanically evaluated during simulated normal walking and chair rising. A 20 mm diameter canal was created in the femoral necks of five fresh frozen human cadaver bones and the femoral heads were resected at the smallest cross-sectional area of the neck. The relatively short, polished, taper-shaped prostheses were cemented centrally in this canal according to a standardized procedure. A servohydraulic testing machine was used to apply dynamic loads to the prosthetic head. Radiostereophotogrammetric analysis was used to measure rotations and translations between the prosthesis and bone. In addition, the reconstructions were loaded until failure in a static, displacement-controlled test. During the dynamic experiments, the femoral necks did not fail and no macroscopical damage was detected. Maximal values were found for normal walking with a mean rotation of about 0.2° and a mean translation of about 120 μm. These motions stabilized during testing. The mean static failure load was 4714 N. The results obtained in this study are promising and warrant further development of this type of minimal invasive hip prosthesis.

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.

Fractures of the hip in children

Fractures of the hip are uncommon in children, and their importance is related not to the frequency of the injury but to the frequency of complications. Many of these complications can be minimized or avoided by anatomic reduction and internal fixation. Open reduction frequently is necessary to obtain a stable, anatomic reduction. Regardless of the age of the child, stable fixation of the fracture must be given priority over preservation of the proximal femoral physis. The development of osteonecrosis, however, is most likely related to the severity of the initial injury and is largely unaffected by treatment of the fracture.

Resurfacing hip prostheses revisited: failure analysis during a 16-year follow-up

We conducted a prospective study of the clinical and radiographic variables related to the survival of 114 cementless resurfacing double-cup hip replacements (RHR) with a mean follow-up of 9 (range: 1--16) years. Three patients died, and 22 were unavailable for the final review in 2003. Sixty-one RHRs had to be revised to a total hip replacement. Failure analysis of these revised RHRs showed femoral head and neck resorption under the prosthesis in 33, acetabular protrusion in seven, both femoral and acetabular resorption in 14 and a femoral-neck fracture in three. One hip had dislocated, and there were three hips with unexplained pain. The Kaplan-Meier 5-year mean survival was 92%, the 10-year survival was 47% (95% CI 37--57%) and the 15-year survival was 30% (95% CI 20--40%). Pre-operative joint destruction (grade 1), a high degree of radiological osteoporosis, a body mass index >25 and prosthesis mismatch were significantly related to failure of the RHR. We believe that in young, non-obese patients with pre-operative radiological central destruction but without severe proximal femoral osteoporosis, a resurfacing arthroplasty may have some value. Our failures were mainly due to femoral resorption under the prosthetic femoral component.

Survival of cementless femoral components after osteonecrosis of the femoral head with different etiologies

We reviewed 41 patients with 55 cementless total hip arthroplasty operated for advanced osteonecrosis. Patients were divided into 2 groups according to etiology of the osteonecrosis. The first group included 17 cases with osteonecrosis without a systemic disease and the second group 38 cases with osteonecrosis associated with a systemic disease. The follow-up was on average 6.4 years (range, 2-12.8). Eight (15.4%) stem revisions had to be performed; all of them were in the patients with a systemic disease. Ten-year survival rates with femoral revision as the endpoint were in the first group 100% and in the systemic disease group 68% (P = .03). The data of this retrospective study indicate a correlation between the survival of the femoral component and the etiology of the osteonecrosis.

Resurfacing arthroplasty in osteonecrosis of the hip

Approximately 10% of the total hip replacements performed in the United States are for osteonecrosis. Resurfacing arthroplasty has received renewed interest, with several new designs being implanted worldwide. Proponents of resurfacing arthroplasty describe the advantages of bone conservation, preservation of joint mechanics, more physiologic loading of the bone, lower incidence of perioperative complications, and easier conversion to a secondary procedure if failure occurs. Critics recite previous poor results including high failure rates with femoral and acetabular loosening, osteonecrosis of the femoral head, femoral neck fracture, and loss of acetabular bone stock making the secondary revision procedure more difficult. This article attempts to clarify the advantages and disadvantages of the resurfacing concept as it applies to the treatment of osteonecrosis of the femoral head.

Higher failure rate and stem migration of an uncemented femoral component in patients with femoral head osteonecrosis than in patients with osteoarthrosis

BACKGROUND

Several authors have found poorer outcome after hip replacement for osteonecrosis than after hip replacement for arthrosis. In a retrospective study we evaluated the performance of an uncemented femoral component in patients with osteonecrosis and arthrosis of the hip.

PATIENTS AND METHODS

31 patients operated for osteonecrosis, and 49 patients operated for osteoarthrosis were included. The median follow-up time was 6.1 (2-11) years for the patients with osteonecrosis, and 5.9 (4-8) for the arthrosis patients.

RESULTS

Migration analysis performed by the Einzel-Bild-Roentgen Analysis (EBRA) technique revealed a median stem migration of 1.5 (-8.8-0) mm in the patients with osteonecrosis, but only 0.6 (-2.8-0.7) mm in the patients with arthrosis (p < 0.001). Survivorship analysis with stem revision as endpoint for failure was 74% (95% CI: 55-94) in the osteonecrosis, and 98% (95% CI: 94-100) in the arthrosis group (p = 0.01).

INTERPRETATION

We suggest that the higher failure rate and stem migration of uncemented total hip replacement in the patients with osteonecrosis is a consequence of the disease. On the basis of these findings, we recommend close monitoring of the patients with osteonecrosis, which should include migration measurements.

Preservation of bone mineral density of the proximal femur following hemisurface arthroplasty

Bone mineral density of the proximal femur was measured in six patients who underwent hemisurface replacement for osteonecrosis of the femoral head. Bone mineral density values in operated and contralateral nonoperated hips were compared. In four patients who had sequential examinations, bone mineral density was compared over time. Average patient age was 34.6 years, average follow-up was 9.1 years, and mean follow-up of bone mineral density measurements was 6.6 years. Average bone mineral density variation was 0.0048 to -0.0264 g/cm2 per year in all five regions in nonoperated hips and -0.012 to -0.0300 g/cm2 in operated hips. These results support bone conservation and preservation with hemiresurfacing arthroplasty in young patients with osteonecrosis of the femoral head.

Surface arthroplasty for osteonecrosis of the hip: hemiresurfacing versus metal-on-metal hybrid resurfacing

Eighty-four hips with Ficat stage III and IV osteonecrosis were treated: 56 with metal-on-metal surface arthroplasty (MMSA) and 28 with hemi-surface arthroplasty (HSA). Average follow-up was 4.9 years. UCLA hip scores were significantly better for MMSA versus HSA for function and activity as well as Harris Hip scores and physical component of the SF-12 scores. In the MMSA group, 2 hips were revised to total hip arthroplasty for femoral loosening, and 5 hips had adverse radiological changes. In the HSA group, 4 hips were revised (1 sepsis and 3 for pain). There was no evidence of any femoral loosening or neck narrowing in the HSA group. Although the functional clinical outcome of MMSA is superior to HSA, long-term follow up of MMSA will determine the reliability of the femoral fixation.

Outcome of hemiresurfacing in osteonecrosis of the femoral head

Hemiresurfacing of the femoral head for treatment of osteonecrosis has been proposed as a reasonable alternative to total hip arthroplasty. The results of 59 patients with Ficat Stage III osteonecrosis done by a single surgeon are reviewed. At an average followup of 4.5 years, 16 patients were considered failures because of conversion to total hip arthroplasty or considerable groin pain requiring medication. Failure did not correlate with age, body mass index, preoperative length of symptoms, acetabular articular cartilage status at the time of surgery, or cause of the underlying disease. The only factor associated with failure was a lower preoperative Harris hip score. Conversion of the failed implants to total hip arthroplasty was straightforward, confirming the conservative nature of the procedure. However, pain relief and recovery after resurfacing are less reliable than that associated with total hip arthroplasty. This procedure may be appropriate for patients younger than 30 years, given the ease of conversion to THR if failure occurs. The patient should be counseled regarding expectations.

Effectiveness of total hip arthroplasty in the management of hip osteonecrosis

Total hip replacement initially showed universally bad results when performed in hips with advanced stages of osteonecrosis. Newer techniques and implants remarkably improved these results. Today cementless or hybrid total hip arthroplasty for osteonecrosis is proven to be safe and effective and to have survivorship similar to cases with osteoarthritis. Newer,more durable bearing surfaces will further improve the longevity of this procedure.

Short-term results of hemi-resurfacing for osteonecrosis of the femoral head

Published evidence has supported the use of femoral head resurfacing for patients with osteonecrosis of the femoral head. Between June 1999 and April 2001 we prospectively studied 15 femoral heads resurfaced in 12 patients with the Conserve Resurfacing Hemiarthroplasty. The male to female ratio was 8:4 and the mean age 38.7 years (range 26-60). The mean follow-up was 22.8 months (range 4-36). The senior author performed all procedures. There was one case of Ficat stage II, 9 cases of stage III and 5 cases of early stage IV. The mean time from onset of symptoms to surgery was 33.5 months (range 9-60). There were no intra or post-operative complications associated with any of the hemiarthroplasty procedures.

RESULTS

Nine of the fifteen patients had a poor result that warranted revision surgery within two years of prosthesis implantation. We conclude that in our hands the results of femoral resurfacing hemiarthroplasty are unpredictable and advise caution when recommending the procedure to patients with osteonecrosis of the femoral head. (Hip International 2004; 14: 174-81).

Management of Ficat stage III and IV osteonecrosis of the hip

Management of Ficat stage III and IV osteonecrosis of the hip remains controversial. Because patients usually require a surgical intervention in their mid 30s, the initial procedure is often the first step in a lifelong treatment plan. Long-term results of total hip arthroplasty in these young, active patients have been disappointing. New alternative bearing surfaces (metal-on-metal, ceramic-on-ceramic, and highly cross-linked polyethylene) and improved methods of fixation may lead to better long-term results. Nevertheless, bone- and joint-preserving procedures, such as free-vascularized fibular graft, trapdoor grafting, redirectional osteotomy, or hemiresurfacing hip arthroplasty, should be considered. The choice of option depends on patient age, the cause of osteonecrosis, the extent of femoral head involvement, and the condition of the acetabular articular cartilage. The goals of treatment are to relieve pain, improve function, minimize morbidity, and maintain options for secondary procedures.

Impact of implant design on femoral head hemiresurfacing arthroplasty

Two consecutive series of cemented femoral hemiresurfacing arthroplasty for patients with Ficat Stage III and early Stage IV osteonecrosis of the femoral head were studied to identify the impact of design on the clinical and radiographic results. Group I (30 patients, 33 hips) components had a cobalt chrome shell with a tapered inner dimension, no stem, and sizes in 2-mm increments. Group II (37 patients, 51 hips) components differed by adding a proportional stem, increased spherical coverage, and sizes in 1-mm increments. The average age for the patients in both groups was 40 years. Fifty percent of the patients in Group I were men: in 43% of patients osteonecrosis was associated with steroid use and in 21% of patients it was associated with alcohol use. Thirty-three percent of the patients in Group II were men: in 41% of patients osteonecrosis was associated with steroid use and in 17% of patients it was associated with alcohol use. The average followup is 42 months for Group I and 24 months for Group II. Neither group experienced infections, nerve palsies, dislocations, or loosening. In Group I, two patients died of unrelated causes and five patients had reoperations, two for femoral neck fractures, and three for unsatisfactory pain relief. No patients in Group II had femoral neck fractures but three patients had reoperations for unsatisfactory pain relief. The stemmed component in Group II has resulted in an improvement in component position and elimination of femoral neck fractures in this series.

The biomechanical results of total hip resurfacing arthroplasty

BACKGROUND

With the advent of more wear-resistant bearings, there is renewed interest in resurfacing total hip arthroplasty. However, there is a paucity of information on the biomechanical results of this type of arthroplasty compared with those of contemporary total hip arthroplasty.

METHODS

Using standardized radiographs, we measured and compared the biomechanical parameters that affect the hip joint reactive forces in fifty hips that had a metal-metal surface replacement with those parameters in forty hips that had a contemporary cementless total hip replacement performed during the same time-period by the same surgeon.

RESULTS

On the average, the arthritic hips that were treated with metal-metal surface replacement had had a more valgus preoperative neck-shaft angle and less horizontal femoral offset than the normal, contralateral hips (p = 0.0003). After both the metal-metal surface replacements and the cementless total hip replacements, the hip center of rotation was medialized by approximately 6 mm. Both procedures were associated with an average increase in limb length of approximately 3 or 4 mm. After the metal-metal surface replacements, the horizontal femoral offset was essentially equal to the preoperative value, but both values averaged about 8 mm less than those on the normal, contralateral side (p < 0.00001). In the hips with a conventional total hip replacement, the horizontal femoral offset increased an average of 9.5 mm compared with the preoperative value and was an average of 5 mm more than that for the normal, contralateral hip (p = 0.001).

CONCLUSIONS

The biomechanical results of total hip resurfacing depend on the preoperative anatomy of the proximal part of the femur. Limb lengthening of 1 cm can be achieved, but horizontal femoral offset is essentially unchanged by hip resurfacing. Horizontal femoral offset can be increased reliably with a contemporary total hip replacement. Arthritic hips of limbs that are more than 1 cm shorter than the contralateral limb or that have a comparatively low horizontal femoral offset may be better served by a contemporary total hip replacement. These biomechanical limitations should be considered in the selection of hips for resurfacing.

LEVEL OF EVIDENCE

Therapeutic study, Level III-1 (case-control study). See Instructions to Authors for a complete description of levels of evidence.

Hemiresurfacing arthroplasty of the hip for failed free-vascularized fibular graft

Management of Ficat stage III and IV osteonecrosis of the hip remains challenging, with the average patient aged in the mid 30s. Joint- and bone-preserving procedures such as free vascularized fibular graft, redirectional osteotomies, and hemiresurfacing hip arthroplasty are often considered. If these treatments fail, that is, after progression of joint destruction or persistent pain and decreasing function, total hip arthroplasty is often the procedure of choice. We describe the case of a patient with failed bilateral free vascularized fibular graft treated with bilateral hemiresurfacing arthroplasty.

Categorization diminishes the reliability of hip scores

Scoring systems frequently are used to assess the outcome of total hip arthroplasty. The result may be presented as a numeric value, or in descriptive terms such as excellent, good, fair, and poor (category system). The current study was done to investigate the influence of descriptive and numeric outcomes for interobserver reliability and interscore correlation of five different hip scores. Sixty-four patients (83 hips) were included in the study. The average age of the patients at followup was 70 years (range, 48-88 years). The average followup was 6.2 years (range, 2-17 years). For the numeric outcome a higher interobserver reliability (correlation coefficient, 0.71-0.81) and interscore correlation (correlation coefficient, 0.81-0.92) were found compared with the category system (interobserver reliability[correlation coefficient, 0.57-0.72]; interscore correlation [correlation coefficient, 0.46-0.62]). Findings from the study suggest that categorization of the results of total hip arthroplasty reduces interobserver reliability and interscore correlation.

Hip arthroplasty after failed free vascularized fibular grafting for osteonecrosis in young patients

This study reports the results of total hip arthroplasty (THA) for osteonecrosis after failed free vascularized fibular grafting (FVFG) at a 5-year minimum follow-up. In this study, 73 patients (89 THA) were treated for failed FVFG, and survival of THA was discussed. Clinical outcome was measured using a pain and function survey (possible 91 points) in 84 hips and Harris Hip scores (HHS, 100 possible points) for 52 hips. Survival was 94.4% at 5 years, 85.4% at 10 years, and 82% overall. Average HHS at final follow-up improved to 77.5 (P <.05). The average clinical result after THA was 68 of 91 points. In this study, 58% of patients had a good or excellent HHS. The overall revision rate for proximal ingrowth stems was 13% at an average follow-up of 9.1 years. Only 4 patients required stem revision for loosening (7.4%). THA after FVFG provides improved functional results comparable to the published results of primary THA in osteonecrosis in young patients.

The stubborn hip: idiopathic avascular necrosis of the hip

OBJECTIVE

To highlight the unusually indolent course of avascular necrosis in this patient, the risk factors of which chiropractors should be aware, the necessity of and means to an early diagnosis, the limitations of plain film radiographs, as well as the current medical treatments.

CLINICAL FEATURES

A 27-year-old male professional soccer player had a tight and achy right hip for approximately 6 years, a condition that increased with physical activity. His active range of motion was limited by 25% in extension and abduction, and all resisted ranges of motion produced pain. After an equivocal radiograph and bone scan, magnetic resonance imaging revealed a subchondral defect located on the superior aspect of the right femoral head, consistent with avascular necrosis of the femoral head.

INTERVENTION AND OUTCOME

Presurgical management included Cybex testing, massage, myofascial release, interferential current, muscle strengthening, and muscle balancing exercises 3-5 times per week for 5 months. The patient underwent a curette procedure. Six weeks later, he returned to the chiropractic office for postsurgical rehabilitation, in which he is still involved today. He has made progress with respect to flexibility, strength, and muscle coordination.

CONCLUSIONS

Idiopathic avascular necrosis of the hip is a clinical entity characterized by pain in the hip made worse with activity and at night, which may radiate to the groin, back, or thigh. Often, physical exam and radiographic findings are equivocal, at which point advanced imaging such as magnetic resonance imaging should be ordered to identify the disease in its earliest stages.