Aims

To evaluate the rate of dislocation following dual mobility total hip arthroplasty (DM-THA) in patients with displaced femoral neck fractures, and to compare rates of dislocation, surgical-site infection, reoperation, and one-year mortality between DM-THA and bipolar hemiarthroplasty (BHA).

Deep gluteal syndrome is an increasingly recognized disease entity, caused by compression of the sciatic or pudendal nerve due to non-discogenic pelvic lesions. It includes the piriformis syndrome, the gemelli-obturator internus syndrome, the ischiofemoral impingement syndrome, and the proximal hamstring syndrome. The concept of the deep gluteal syndrome extends our understanding of posterior hip pain due to nerve entrapment beyond the traditional model of the piriformis syndrome. Nevertheless, there has been terminological confusion and the deep gluteal syndrome has often been undiagnosed or mistaken for other conditions. Careful history-taking, a physical examination including provocation tests, an electrodiagnostic study, and imaging are necessary for an accurate diagnosis.

After excluding spinal lesions, MRI scans of the pelvis are helpful in diagnosing deep gluteal syndrome and identifying pathological conditions entrapping the nerves. It can be conservatively treated with multidisciplinary treatment including rest, the avoidance of provoking activities, medication, injections, and physiotherapy.

Endoscopic or open surgical decompression is recommended in patients with persistent or recurrent symptoms after conservative treatment or in those who may have masses compressing the sciatic nerve.

Many physicians remain unfamiliar with this syndrome and there is a lack of relevant literature. This comprehensive review aims to provide the latest information about the epidemiology, aetiology, pathology, clinical features, diagnosis, and treatment.

Cite this article: Bone Joint J 2020;102-B(5):556–567.

Ceramic bearings have several desirable properties, such as resistance to wear, hardness, and biocompatibility, that favour it as an articulating surface in hip arthroplasty. However, ceramic fracture remains a concern. We have reviewed the contemporary literature, addressing the factors that can influence the incidence of ceramic bearing surface fracture.

Cite this article: Bone Joint J 2019;101-B:897–901.

Introduction

Venous thromboembolism (VTE), including pulmonary embolism (PE) resulting from deep vein thrombosis (DVT), remains a well-known serious complication after femoral fractures. The low molecular heparin is widely used to prevent VTE. This study compared the effectiveness of VTE prevention between dalteparin and enoxaparin.

Background

Although thigh pain is an annoying problem after total hip arthroplasty (THA), little information has been known about its natural course.

Introduction

Arthroplasties of hip and knee are associated with blood loss, which may lead to adverse patient outcome. Jehovah's Witnesses do not accept blood transfusion. Performing arthroplasties in Witness patients without transfusion has been a matter of concern. We developed a protocol, which avoids transfusion in arthroplasties of Witness patients, and evaluated the feasibility and safety of the protocol.

Introduction

In comminuted intertrochanteric fractures, various operative options have been introduced. The purpose of this study was to determine whether there were differences in clinical and radiologic outcomes among bipolar hemiarthroplasty(BH), compression hip screw(CHS) and proximal femur nail antirotatory(PFNA) in treating comminuted intertrochanteric fractures(AO type, A2(21, 22, 23))

Background:

Two-stage reconstruction, reimplantation after removal of an infected prosthesis, has been considered to be the gold standard for treatment of infected hip arthroplasty. However, during the removal of a well-fixed femoral stem, the proximal femur can be damaged and a sequestrum can be formed, which might lead to chronic osteomyelitis and difficulty in reimplantation. We wanted to determine whether infection after hip arthroplasty can be treated without removal of a well-fixed stem.

Pre-operative planning for total hip replacement (THR) is challenging in hips with severe acetabular deformities, including those with a hypoplastic acetabulum or severe defects and in the presence of arthrodesis or ankylosis. We evaluated whether a Rapid Prototype (RP) model, which is a life-sized reproduction based on three-dimensional CT scans, can determine the feasibility of THR and provide information about the size and position of the acetabular component in severe acetabular deformities. THR was planned using an RP model in 21 complex hips in five men (five hips) and 16 women (16 hips) with a mean age of 47.7 years (24 to 70) at operation. An acetabular component was implanted successfully and THR completed in all hips. The acetabular component used was within 2 mm of the predicted size in 17 hips (80.9%). All of the acetabular components and femoral stems had radiological evidence of bone ingrowth and stability at the final follow-up, without any detectable wear or peri-prosthetic osteolysis. The RP model allowed a simulated procedure pre-operatively and was helpful in determining the feasibility of THR pre-operatively, and to decide on implant type, size and position in complex THRs.

Cite this article: Bone Joint J 2013;95-B:1458–63.

This prospective multicentre study was undertaken to determine whether the timing of the post-operative administration of bisphosphonate affects fracture healing and the rate of complication following an intertrochanteric fracture. Between August 2008 and December 2009, 90 patients with an intertrochanteric fracture who underwent internal fixation were randomised to three groups according to the timing of the commencement of risedronate treatment after surgery: Group A (from one week after surgery), Group B (from one month after surgery), and Group C (from three months after surgery). The radiological time to fracture healing was assessed as the primary endpoint, and the incidence of complications, including excessive displacement or any complication requiring revision surgery, as the secondary endpoint. The mean time to fracture healing post-operatively in groups A, B and C was 10.7 weeks (sd 4.4), 12.9 weeks (sd 6.2) and 12.3 weeks (sd 7.1), respectively (p = 0.420). At 24 weeks after surgery, all fractures had united, except six that had a loss of fixation. Functional outcomes at one year after surgery according to the Koval classification (p = 0.948) and the incidence of complications (p = 0.386) were similar in the three groups.

This study demonstrates that the timing of the post-operative administration of bisphosphonates does not appear to affect the rate of healing of an intertrochanteric fracture or the incidence of complications.

A variety of radiological methods of measuring version of the acetabular component after total hip replacement (THR) have been described. The aim of this study was to evaluate the reliability and validity of six methods (those of Lewinnek; Widmer; Hassan et al; Ackland, Bourne and Uhthoff; Liaw et al; and Woo and Morrey) that are currently in use. In 36 consecutive patients who underwent THR, version of the acetabular component was measured by three independent examiners on plain radiographs using these six methods and compared with measurements using CT scans. The intra- and interobserver reliabilities of each measurement were estimated. All measurements on both radiographs and CT scans had excellent intra- and interobserver reliability and the results from each of the six methods correlated well with the CT measurements. However, measurements made using the methods of Widmer and of Ackland, Bourne and Uhthoff were significantly different from the CT measurements (both p < 0.001), whereas measurements made using the remaining four methods were similar to the CT measurements. With regard to reliability and convergent validity, we recommend the use of the methods described by Lewinnek, Hassan et al, Liaw et al and Woo and Morrey for measurement of version of the acetabular component.

Background: Ceramic-on-ceramic couplings are an attractive alternative bearing surfaces to eliminate or reduce problems related to polyethylene wear debris. Past disappointing experiences with alumina ceramic bearings have led to many improvements in the manufacture and the design of ceramic implants. The purpose of this study was to report the results of contemporary alumina-on-alumina total hip arthroplasties (THAs) with regard to wear, osteolysis, and fracture of the ceramic after a 10-year minimum follow-up.

Methods: We evaluated the results of a series of 66 primary alumina-on-alumina THAs with a metal-backed socket and a cementless stem in 59 patients. All of the patients were 64 years old or younger (mean, 42 years), and a single surgeon performed all of the procedures. They were evaluated clinically and radiographically at the 120 to 126 months follow-up (average, 123 months). During the follow-up, special regards were addressed to wear, periprosthetic osteolysis and ceramic failure.

Results: During the follow-up period, two patients (two hips) had died with the prosthesis in situ as the result of an unrelated medical condition. The mean Harris hip score was 94 points at the latest follow-up evaluation. All of the prostheses had radiographic evidence of a bone ingrowth. No implant was loosened radiographically and no implant was revised. Ceramic wear was not detectable in the 28 hips where differentiation of the femoral head from the cup was possible on radiographs. Periprosthetic osteolysis was observed in no hip. A fracture of the alumina femoral head and a peripheral chip fracture of the alumina insert occurred in one hip following a major motor vehicle accident. A periprosthetic femoral fracture, which required open reduction and internal fixation with metal cables, had occurred in one hip. This fracture healed without problem.

Conclusion: The results of contemporary alumina-on-alumina THAs with a metal-backed socket and a cementless stem were encouraging after a minimum follow up of 10 years. We believe that these improved alumina-on-alumina bearing implants offer a promising option for younger active patients.

We evaluated 3 cases of ceramic-on-ceramic THA in that the evidence of the impingement between the metal neck and the ceramic liner was found.

Between July 2007 and January 2008, impingement between the metal and the ceramic liner was found in 3 cases of ceramic-on-ceramic THA during re-operation. The re-operation was performed 3–6 years after the primary surgery because of ceramic head fracture, deep infection and cup loosening. All patients frequently sat on the floor in tailor fashion but did not have any sound in the hip after THA.

In all cases, V-shaped indented wear scar was found on the postero-superior aspect of the metal neck. Two ceramic liners could be retrieved. Both showed black staining in the postero-superior portion of the rim. The outer edge of the bearing surface of the retrieved acetabular liners was evaluated with SEM. The black stained area of the acetabular liner rim was found to be roughened. A micro-crack propagating into the deep portion of the ceramic liner was observed in one liner.

Our observations suggest that impingement between the ceramic liner and the metal neck can cause crack formation leading to ceramic liner failure in vivo.

Introduction: The etiology of transient osteoporosis of the hip (TOH) remains unknown. Recently subchondral bone injury of the femoral head has been proposed as a possible etiology.

Methods: A 28-year-old woman presented with bilateral hip pain that started sequentially during the peripartum period. Diagnosis of TOH was made based on typical findings of plain radiographs and magnetic resonance images. The subchondral trabeculae of the femoral head were evaluated on serially taken coronal multiplanar reformation CT images.

Results: At 4 weeks after pain onset, a marked decrease in the sclerotic density with irregular discontinuation was observed in the primary compression trabeculae. At 12 weeks, a focal area of irregular thickening of trabeculae was observed. At 20 weeks, sclerotic density of trabeculae recovered markedly and the focal area of irregular trabecular thickening disappeared. At 1 year, subchondral trabeculae recovered almost completely.

Conclusion: Evidence of subchondral trabecular injury was observed in the femoral heads of TOH.

Introduction: Osteonecrosis of the femoral head occurs in young patients. The preservation of the hip joint is vitally important because hip replacement arthroplasty is associated with high rates of failure in young and active patients. Curved intertrochanteric varus osteotomy is one of several joint preserving procedures used to treat these patients.

Methods: Between June 2003 and June 2006, 46 patients (49 hips) who had osteonecrosis of the femoral head were treated with curved intertrochanteric varus osteotomy. There were 23 men and 23 women who had a mean age at the time of osteotomy was 33 years (range, 17 to 51 years). The osteotomy was fixed with a 120 degree compression hip screw in the first 34 hips and with a 95 degree dynamic condylar screw in the remaining 15 hips. Clinical evaluation was performed using the scoring system of Merle d’Aubigne et al. Radiological failure of the operation was defined as further collapse of the femoral head by more than 2 mm or progressive narrowing of the joint space compared with the immediate postoperative radiograph.

Results: The mean duration of follow-up was 22 months (range, 12 to 48 months). One patient (one hip) required a total hip arthroplasty due to loss of fixation and penetration of the lag screw into the joint space. In two patients (two hips), the plate fractured at 3 and 4 months after the operation, which was changed to a new plate. Thus, 48 of the 49 hips survived at a mean follow-up 22 months. In these 48 hips, the mean Merle d’Aubigne hip score was 17.2 points at latest evaluation and there was no instance of radiologic failure.

Discussion: Curved intertrochanteric varus osteotomy is a satisfactory joint preserving method to treat osteonecrosis of the femoral head.

Introduction: We evaluated the follow-up results of subchondral fatigue fractures of the femoral head.

Methods: Between July 1999 and August 2005, 10 male patients presented with a collapsed subchondral fatigue fracture of the femoral head. The flattening of the femoral head was mild in 4 cases, moderate in 3 cases and severe in 3 cases. Three cases were misdiagnosed as osteonecrosis and since treated with multiple drillings or bone grafts. One case was treated with impaction bone grafting. The remaining cases were treated non-operatively. All patients were followed more than 2 years after onset of hip pain.

Results: At the latest follow-up, no patient had remarkable pain or disability limiting daily activity. Degenerative changes of Tönnis grade 1 were observed in 5 cases.

Discussion: Unlike collapsed osteonecrosis, collapsed subchondral fracture of the femoral head had a benign clinical course.

Introduction: A hypothesis that combined necrotic angle measurement using MRI scans predicts the subsequent risk of collapse of femoral head osteonecrosis was tested.

Materials and Methods: Thirty-seven hips with early-stage osteonecrosis in 33 consecutive patients were investigated. The arc of the necrosis was measured by the method of Kerboul et al. using mid-coronal and mid-sagittal MRI scans of the femoral head instead of anteroposterior and lateral radiographs, and the two angles were added. Hips were classified into four categories based on the magnitude of the added angle; grade 1 (< 200), grade 2 (200–249), grade 3 (250–299), and grade 4 (≥300). After the initial evaluations, the hips were randomly assigned to a core-decompression group or a non-operatively-treated group. Patients underwent regular follow-up until femoral head collapse or for a minimum of five years.

Results: Seven hips in grade 4 and 16 hips in grade 3 developed femoral head collapse in 36 months; six out of nine hips in grade 2, and none of five hips in grade 1 developed collapse (log rank test, p< 0.01). In a retrospective analysis, none of four hips with combined necrotic angle < 190 (low risk group) collapsed, and all 25 hips with combined necrotic angle > 240 (high risk group) collapsed, and four (50%) of eight hips with combined necrotic angle between 190 and 240 (moderate risk group) collapsed during the study.

Discussion: The Kerboul combined necrotic angle ascertained by MRI scans instead of radiographs is a major predictor of future femoral head collapse.

Introduction: The hypothesis that combined necrotic angle measurements using magnetic resonance imaging (MRI) scans predicts the subsequent risk of collapse of femoral head osteonecrosis was tested.

Materials and Methods: Thirty-seven hips with early-stage osteonecrosis in 33 consecutive patients were investigated. The arc of the necrosis was measured by the method of Kerboul et al using mid-coronal and mid-sagittal MRI scans of the femoral head instead of anteroposterior and lateral radiographs, and the two angles were added. Hips were classified into four categories based on the magnitude of the added angle; grade 1 (< 200°), grade 2 (200°–249°), grade 3 (250°–299°), and grade 4 (≥300°). After the initial evaluations, the hips were randomly assigned to a core-decompression group or conservatively-treated group. Patients underwent regular follow-up until femoral head collapse or for a minimum of five years.

Results: Seven hips in the grade 4 category and 16 hips in the grade 3 category developed femoral head collapse in 36 months; six out of nine hips in the grade 2 category, and none of five hips in the grade 1 category developed collapse (log rank test, p< 0.01). In a retrospective analysis, none of the four hips with a combined necrotic angle < 190° (low risk group) collapsed, whereas all 25 hips with a combined necrotic angle > 240° (high risk group) collapsed, and four (50%) of eight hips with a combined necrotic angle between 190° and 240° (moderate risk group) collapsed during the study.

Discussion: The Kerboul combined necrotic angle ascertained by MRI scans instead of radiographs is a major predictor of future collapse.

Introduction: The rate of failure of primary total hip arthroplasty in patients with osteonecrosis of the femoral head is higher than in patients with osteoarthritis. The purpose of this prospective study was to document the clinical and radiographic results of arthroplasty with so-called third generation cementing and the results of second generation cementless total hip arthroplasty in ninety-eight consecutive patients with osteonecrosis of the femoral head.

Materials and Methods: Fifty patients who had simultaneous bilateral total hip arthroplasties with a cemented stem in one hip and a cementless stem in the other and forty-eight patients who had unilateral total hip arthroplasties with a cementless stem were included in the study. A cementless acetabular component was used in all hips. The presumed cause of the osteonecrosis was ethanol abuse in fifty-seven patients, unknown in twenty-seven, fracture of the femoral neck in nine, and steroid use in five. There were eighty men and eighteen women. The mean age the time of the arthroplasty was 47 years (range, twenty-six to fifty-eight years). Clinical and radiographic evaluations were performed preoperatively, at six weeks, at three, six, and twelve months; yearly thereafter. The average duration of follow-up was 9.3 years.

Results: The average Harris hip scores in the group treated with unilateral arthroplasty (97 points) and the group treated with bilateral arthroplasty (94 points) were similar at the time of final follow-up. They were also similar between the group treated with cement (mean, 96 points) and that treated without cement (95 points). No component had aseptic loosening in either group. In one hip, a cemented femoral stem (2 %) and a cementless cup were revised because of infection. Two cementless stems (2%) were revised because of fracture of the proximal part of the femur with loosening of the stem. Annual wear of the polyethylene liner averaged 0.22 mm in the group treated with cement (a zirconia head) and 0.14 mm in the group treated without cement (a cobalt-chrome head). The prevalence of osteolysis in zones 1 and 7 of femur was 16 % in the femur was 16% in the group treated with cement and 24% in the group treated without cement.

Discussion: Advances in surgical technique and better designs have greatly improved the long-term survival of cemented and cementless implants in young patients with osteonecrosis of femoral head. Although there was no aseptic loosening of the components, the high rate of linear wear of the polyethylene liner and high rate of osteolysis in these high risk young patients remain challenging problems.

Introduction: Necrotic fatty marrow is yellow, thick, and turbid like pus and the fat cell is counted as white blood cell in automated cell counting. When necrotic fatty marrow leaks into the hip joint through a crack in the cartilage of the osteonecrotic femoral head, a misdiagnosis of pyogenic infection can be made. The authors report cases of osteonecrosis of the femoral head, in which a misdiagnosis of pyogenic infection was made during the operation.

Materials and Methods: Between September 1997 and December 2001, pyogenic arthritis was suspected during the operation in seven patients who were operated on due to advanced osteonecrosis of the femoral head. The markers of infection including white blood cell count, erythrocyte sedimentation rate, and C reactive protein in preoperative laboratory examination were normal in all of the seven patients. Total hip arthroplasty was scheduled for all patients. When the hip joint capsule was incised, joint fluid gushed out in all patients. The appearance, white blood cell count in automated cell counting, microscopic findings, and the results of culture of the joint fluid were evaluated.

Results: The joint fluid was yellow, thick and turbid like pus. A pyogenic arthritis was suspected and the joint fluid was sent to the laboratory for automated blood cell count, smear and culture. The count of white blood cells ranged from 5800 to 18000 in automated cell counting. No microorganism was identified on joint fluid smear. On microscopic cell counting using a hemocytometer, white blood cells were rarely seen and the majority of cells which were counted as white blood cells, were necrotic fat cell. Total hip arthroplasty was performed immediately after microscopic examination of the joint fluid. No microorganism was identified in cultures of the joint fluid. There was no evidence of infection after total hip arthroplasty at a minimum of two-year followup.

Discussion: When necrotic fatty marrow leaks into the hip joint, the joint fluid looks like pus and white blood cell counts of the joint fluid is increased in automated cell counting because fat cells are counted as white blood cells. In this situation, microscopic examination of the joint fluid is necessary. If the white blood cell count is not increased in microscopic cell counting, replacement arthroplasty can be performed without risk of infection.

Introduction: Some patients with collapsed osteonecrosis of the femoral head do not need any specific treatment because of mild symptoms or disability. The general features of this patient population were evaluated.

Materials and Methods: Forty-five cases of collapsed osteonecrosis of the femoral head in 38 patients were included in this study. These patients visited outpatient clinics for the first time from January 1996 to December 2002. In all cases, pain developed at least 3 years before the last follow-up, but no specific treatment was necessary. There were 27 men and 11 women. The mean age at the onset of pain was 41 years (range, 17 to 72 years). The duration from the onset of pain to the last follow-up was 36 to 167 months (mean, 73 months). The general and radiological features were evaluated.

Results: Risk factors included steroid therapy in 18, alcoholism in 16, other in 1 case; 10 cases had no risk factors (idiopathic). In 29 patients, both femoral heads were involved. Extent of the necrosis was 37 to 89 percent (mean, 62 percent). The amount of depression was 0.5 to 17 mm (mean, 2.2 mm).

Discussion: Steroid therapy was the most frequent risk factor in this patient population. In most cases, the amount of depression was less than 3 mm. Most patients remembered that the pain was most severe at its onset and improved over the next several months.

Introduction: Stress fracture of the femoral head is a rare condition and usually occurs in people with poor bone quality as an insufficiency fracture. We evaluated the clinical aspects of subchondral fatigue fractures of the femoral head (SFFFH) that occurred in young healthy people.

Materials and Methods: Between January 1998 and November 2001, 7 cases of SFFFH in 5 patients were treated. The characteristics of this condition were ascertained by assessing the clinical course and findings of radiographs, bone scintigrams, and magnetic resonance (MR) images.

Results: All patients were male military recruits in their early twenties. Pain developed within 6 months after recruitment. On initial radiographs, definite abnormal findings were observed in 3 hips of 2 patients. In 2 of them, the femoral head was markedly collapsed. In the other 4 hips, no definite abnormal findings were noticed. The bone scintigrams showed increased radionuclide uptake in the femoral head. MR images demonstrated localized abnormal signal intensity areas (bone marrow edema pattern) in the femoral head. In all cases, MR crescent signs were observed. In the cases without collapse of the femoral head, the pain decreased gradually and disappeared completely in 6 months with improving findings on follow-up MR images. The collapsed cases needed surgical treatment: total hip arthroplasty or strut iliac bone grafting.

Discussion: When a military recruit or an athlete is complaining of hip pain, a high index of suspicion for SFFFH is necessary to prevent the collapse of the femoral head. Bone scintigrams are of great value as a screening tool. Osteonecrosis of the femoral head can be differentiated by the findings on MR images.

Introduction: Osteonecrosis of the femoral head (ONFH), a disease of unknown pathogenesis usually involves subchondral bone and shows an improper repair process. The temperature of the subchondral bone of the femoral head was found to increase by a maximum of 2.5 °C in a simulation of walking performed in cadavers. A greater increase in the temperature is expected in the necrotic bone in ONFH because there is no heat dissipation by blood flow. The purpose of this study was to confirm the possibility that hyperthermia is a cause of the poor regeneration of the necrotic bone in ONFH.

Materials and Methods: Necrotic and living bone extracts were prepared from the femoral heads of 4 ONFH patients. Human umbilical vein endothelial cells (HUVECs) were cultured with endothelial cell growth media-2 (EGM-2), EGM-2 supplemented with necrotic bone extracts, and EGM-2 supplemented with living bone extracts. HUVECs were also cultured at temperatures of 40, 40.5, 41 and 42 °C, while controls were maintained at 37 °C. Viable cell numbers of HUVECs were determined by MTS assay at days 1, 4, 6, 8, and 11.

Results: The number of viable cells decreased in hyperthermic conditions of 40.5 to 42 °C (p< 0.05). The addition of living bone extracts induced a significant increase in the number of viable cells during the culture periods (p< 0.05). Necrotic bone extracts did not induce such a significant increase.

Discussion: Local subchondral hyperthermia might be a possible cause of the poor regeneration of the necrotic area in ONFH.

The purpose of current study was to describe the results of complex acetabular fractures treated with open reduction using transtrochanteric approach and arthrotomy of the hip joint. Fourteen consecutive patients with both column fractures of the acetabulum were treated with open reduction and internal fixation. All patients had various associated injuries. Among them, one patient had pelvic abscess associated with traumatic bowel perforation. The acetabulum was approached with Y-shaped triradiate incision, osteotomy of the greater trochanter, and arthrotomy of the hip joint. During the operation, the osteochondral fragments were removed and torn labrum was resected. In 6 patients the fracture was fixed with reconstruction plates and in 8 patients the fracture was fixed with plates and wires. All the patients were followed for an average of 4.6 years(range, 2–8 years). The clinical evaluation was done by the method of Merle d’Aubigne. All the fractures and all osteotomies united at the latest follow up. One patient had delayed hematogenous infection at 5.5 years after the operation. Although myositis ossificans developed in 3 patients it was neither progressive after 1 year nor associated with significant limitation of hip motion. Four patients had narrowing of the hip joint space. Three of them had osteophyte formation around the femoral head. No femoral head necrosis was observed. Eleven patients had excellent or good outcomes in clinical score. No patient underwent total hip arthroplasty. This extensile approach allowed a good exposure of the fracture site, more accurate reduction, and easier fixation of fracture fragments. It also allowed the removal of osteochondral fragments and the resection of torn labrum. However, 3 patients showed osteophyte formation around the femoral head. We are concerned about the further progression of the osteophyte and its clinical implication.

The rate of success of transtrochanteric rotational osteotomy for osteonecrosis of the femoral head may be improved if patients are preselected using MRI. We have used three criteria for selection for osteotomy (i) minor collapse of the infarcted area, loss of congruity or the crescent sign, without narrowing of the joint space or acetabular involvement (ii) patients younger than 55 years and with a painful hip (iii) patients with an intact area constituting an arc of more than 120° between the central vertical line of the femoral head and the posterior or anterior margin of the necrotic portion as seen on a midsagittal MRI. Seventeen patients were selected, with a follow-up of more than 42 months. A bone scan four weeks after operation showed adequate perfusion of the proximal segment in all hips. The hip score of Merle d’Aubigné et al improved from 13.5 points before operation to 17.2 points at the latest follow-up. Further collapse of the femoral head did not occur.

The use of MRI instead of plain radiographs for the selection of patients has improved the success rate of transtrochanteric rotational osteotomy.

Stable fixation after a corrective supracondylar osteotomy in adults is difficult because of the irregularity of the area of bony contact, displacement of the fragments, the predominance of cortical bone, and the need for early mobilisation.

We have used the Ilizarov apparatus for fixation in 15 patients who were treated by complex osteotomies with displacement of fragments for cubitus varus or valgus. Most patients with cubitus varus required medial displacement with rotation of the distal fragment. Those with cubitus valgus required lateral shift of the distal fragment to reduce the medial prominence of the elbow that would otherwise result.

All osteotomies united within the expected time without loss of correction, despite early mobilisation. Complications related to the fixation were few and had resolved at the long-term follow-up.

In a randomised trial comparing core decompression with conservative treatment we tested the hypothesis that the extent of necrosis at the initial MRI predicts the subsequent risk of collapse of the femoral head. After the initial clinical evaluation, including plain radiography and MRI, 37 hips with early-stage osteonecrosis (ON) in 33 patients were randomly assigned to a core-decompression group or a conservatively-treated group. All were followed regularly by clinical evaluation, plain radiography and MRI at intervals of three months. The extent of ON was estimated on the basis of abnormal signal intensity in the weight-bearing portion of the femoral head as determined from a combination of coronal and sagittal MRIs. The arc of the necrotic portion in the mid-coronal image (A) and that in the mid-sagittal image (B) were used to quantify the extent of necrosis by the formula: (A/180) x (B/180) x 100. There was a strong correlation between this index and the risk of collapse before and after adjustment for age, gender, stage and treatment group. We conclude that the extent of the necrotic portion ascertain by this method is a major predictor of future collapse. We propose a systematic method of determining the index of the necrotic portion which may be clinically useful in the management of early-stage ON of the femoral head.

We performed a randomised trial on 37 hips (33 patients) with early-stage osteonecrosis (ON). After the initial clinical evaluation, including plain radiography and MRI, 18 hips were randomly assigned to a core-decompression group and 19 to a conservatively-treated group. All the patients were regularly followed up by clinical evaluation, plain radiography and MRI at intervals of three months. Hip pain was relieved in nine out of ten initially symptomatic hips in the core-decompression group but persisted in three out of four initially painful hips in the conservatively-treated group at the second assessment (p < 0.05). At a minimum follow-up of 24 months, 14 of the 18 core-decompressed hips (78%) and 15 of the 19 non-operated hips (79%) developed collapse of the femoral head. By survival analysis, there was no significant difference in the time to collapse between the two groups (log-rank test p = 0.79). Core decompression may be effective tin symptomatic relief, but is of no greater value than conservative management in preventing collapse in early osteonecrosis of the femoral head.