Purpose. There are some concerns about doing hip resurfacing arthroplasty in ONFH due to bone defect which can cause mechanical weakness of femoral component and highly active young age of patients which can cause high wear rate and failure rate. The purpose of this study is to verify the HRA is safe procedure in ONFH in the aspect of mechanical and biological issue. Materials and Methods. Between December 1998 and May 2005, 185 hips of 169 patients underwent MoM HRA using Birmingham Hip Resurfacing System® at single center. 166 hips (26 hips of female, 140 hips of male) of 144 patients have been reviewed for at least 7 years after MoM HRA. Mean follow-up period was 101.8 (84–178) months. Their mean age at the time of operation was 37.7(16–67) years old. Clinically, Harris hip scores (HHS), UCLA activity scores and range of motion were evaluated. Radiologically, the extent of necrotic area in preoperative MRI and radiolucency around implants, narrowing of retained neck, impingement, stress shielding, and heterotopic ossification were evaluated in the serial anteroposterior and groin lateral radiographs of hip. Complications were defined as joint dislocation, infection, implant loosening, femoral neck fracture and pseudotumor. Failure was defined as revision arthroplasty due to the complications. Results. The extent of necrotic area in preoperative MRI was average 37.6 (13.3–65)%. Clinically, average HHS was improved from 81.7 points to 98.5 points at last follow-up. Average UCLA activity score at last follow-up was 9.0 points. Range of motion at last follow-up was very satisfactory. There was no patient with severe pain around hip joint. Radiologically, radiolucency was shown around acetabular component in 2 cases (1.2%) and around stem of femoral components in 3 cases (1.8%). Fracture of femoral neck was seen in 1 case(0.6%). Moderate narrowing changes of retained femoral neck were noticed in 4 cases (2.4%). Impingement was seen in 12 cases (7.2%). We found only 1 case of osteolysis at Gruen zone III of acetabulum. Heterotopic ossification was found in 5 cases (3.0%). There was no case with hip dislocation, infection or pseudotumor. Revision surgeries after the primary resurfacing arthroplasty were performed in 4 cases (2.4%). Three hips were revised to the conventional total hip arthroplasty (THA) because of loosening of acetabular component and femur neck fracture. One case of femoral component loosening was revised to THA using big metal head with retained acetabular component. Conclusions. MoM HRA in ONFH demonstrates good survivorship in average 101.8 months follow-up study. Most of patients show excellent clinical results with high level of activity postoperatively. Prevalence of complications is extremely lower than concern including the allergic reaction to the metal ion. There was no mechanical failure related to bone defect due to ONFH. This results suggests that MoM HRA in ONFH less than 50% of extent of necrosis can be justified

Osteonecrosis of the femoral head (ONFH) is a debilitating, painful, progressive, and refractory disease that has multiple etiologic risk factors. It is caused by bone cell death, which itself has various causes, leading to femoral head collapse and subsequent osteoarthritis. ONFH primarily influences patients aged from 20 to 50 years; in addition, bilateral hip joints are involved in 75% of patients. Causes include use of corticosteroids, alcohol abuse, previous trauma, hemoglobinopathy, Gaucher disease, coagulopathies, and other diseases. No pharmacologic treatment has been shown to be effective for early ONFH. Outcomes of total hip arthroplasty (THA) for these young and active patients have some drawbacks, primarily due to the young age of these patients, limited lifetime and durability of the implants and their fixation, and the skeletal manifestations of osteonecrosis. As a result of these concerns, there has been an increased focus on early interventions for ONFH aimed at preservation of the native articulation. Core decompression is currently the most widely accepted surgical treatment at the early stage of avascular osteonecrosis (AVN); however, due to limited efficacy, its use has been debated. There is currently no standardised protocol for evaluating and treating osteonecrosis of the femoral head in adults in the United States. Although total hip replacement is the most frequent intervention for treatment of post-collapse (Steinberg stage-IIIB, IVB, V, and VI) osteonecrosis; core decompression is the most commonly offered intervention for symptomatic, pre-collapse (Steinberg stage-IB and IIB) osteonecrosis. Less frequently offered treatments include non-operative, pharmacologic or modality management, osteotomy, vascularised and non-vascularised bone-grafting, hemiarthroplasty, resurfacing and arthrodesis. A promising, minimally invasive, core decompression procedure combined with a mesenchymal stem cell grafting technique which restores vascularity and heals osteonecrotic lesions has become popularised. This procedure is called a bone marrow aspirate concentrate (BMAC) procedure. During a BMAC, mesenchymal stem cells (in the form of concentrated iliac crest bone marrow) are injected through a core decompression tract into the area of necrosis in the femoral head. Most patients with early (pre-collapse) disease have excellent results at 2 to 5 years of clinical follow-up. Patients are weight bearing as tolerated on crutches after the procedure for 6 weeks, and are able to go home on the same day or next day after surgery with minimal pain. We can report on the early, promising results of 300 patients with ONFH treated with BMAC in the United States by two expert hip surgeons with at least 75%-80% survivorship. The care of adults with osteonecrosis of the femoral head is highly variable. This paper will discuss the various non-operative and operative treatment algorithms for ONFH available today. We will also report on a promising, new technique (BMAC), which improves the efficacy of traditional core decompression for early ONFH. The goal of treatment of early ONFH is to avoid THA in young, active patients and this talk will discuss those interventions and treatments which help accomplish that goal

It has been reported that the total steroid dose and acute rejection episodes after organ transplantation is one of the risk factors for the development of osteonecrosis of the femoral head (ONFH), and ONFH in steroid-iduced subgroup may progress more aggressively to femoral head collapse requiring total hip arthroplasty. Despite inherent medical co-morbidities of solid organ transplantation patients, most authors recently have reported successful outcomes of THAs in those patients. But there are few comparative studies on the outcome of THAs for ONFH after different organ transplantations. The purpose of this study was to evaluate and compare a single tertiary referral institution's experience of performing primary THAs in kidney transplantation (KT) and liver transplantation (LT) patients with specific focus on the total steroid dose, clinical outcomes, and relationship between ONFH and absence or presence of acute rejection (AR). Between 1999 and 2010, 4,713 patients underwent organ transplantations (1,957 KT and 2,756 LT) and AR was occurred in 969 patients (20.6%) after transplantation. Among these patients, 131 patients (191 hips) underwent THA for ONFH, and they were retrospectively reviewed. In KT groups, there were 57 men and 36 women with a mean age of 43.7 years. In LT groups, there were 26 men and 13 women with a mean age of 50.4 years. We investigated the dose of steroid administration on both groups, the time period from transplantation to THA, Harris hips score (HHS), visual analogue scale (VAS) and complications. The mean follow up period was 8.1 years (range, 5 to 14 years). One-hundred and thirty-one (2.8%) patients [93 KT and 38 LT] underwent THA after transplantation. The total steroid dose after transplantations was significantly higher in KT group (10,420 mg) than that in LT group (4,567 mg), but the total steroid dose in the first 2 weeks after transplantation was significantly higher in LT group (3,478 mg) than that in KT group (2,564 mg). Twenty-three (2.4%) patients (19 KT and 4 LT) who underwent THA had an episode of AR. In LT group, the total steroid dose in AR groups was significantly higher than that in non-AR groups, whereas in KT group, there was no significant difference of the total steroid dose between AR group and non-AR group. The rate of THAs for ONFH was similar in both groups (2.4% in AR group, 2.9% in non-AR group). The mean time period from transplantation to THA was 986 days for KT and 1,649 days for LT patients. Both groups showed satisfactory HHS and VAS at final follow up, revealed no differences between the groups. The rate of THAs for ONFH was three times higher in KT patients than that in LT patients, but it was similar in both AR group and non-AR group. The total steroid dose was also higher in KT patients compared to LT patients. The clinical outcomes of THA were satisfactory with few complications in both KT and LT patients. Therefore, THAs seems to be a good option for the patients with symptomatic steroid-induced ONFH after KT and LT

Introduction. Legg-Calve-Perthes disease (LCPD), a juvenile osteonecrosis of the femoral head (ONFH), can remain sequelae around hip joint, and results in osteoarthritis necessitating total hip arthroplasty (THA) in middle-age. THA for sequelae of LCPD needs specific concerns for anatomical deformity, leg length discrepancy (LLD), and relatively young patient's age. To date, few studies are available for the results of THA for LCPD sequelae. Moreover, there was no study for the result of Alumina-Alumina THA (Al-Al THA) in patient with LCPD sequelae, even excellent long term outcome of Al-Al THA has been documented in relatively young patients. The aim of this retrospective study is to evaluate the clinical and radiological outcome of Al-Al THA for LCPD sequelae, especially in terms of the restoration of LLD and the occurrence of complication. In addition, we compared the results of THA for LCPD sequelae with those for adult onset ONFH, in which THA is necessitated in relatively young age and excellent long term outcome has been proven after Al-Al THA. Method. Between 1997 and 2007, 41 cementless Al-Al THA were performed in 37 patients with LCPD sequelae and followed up for mean, 10.4 years. Mean age at THA was 43.6 years. Using the propensity score matching with age, gender, and the length of follow-up as variables, 41 THAs in 37 patients were identified from 339 hips in 256 patients who underwent primary Al-Al THA for ONFH during the same period. Clinical and radiological outcomes in terms of implant survival, Harris hip score (HHS), LLD change, and perioperative complication were compared between the two groups. Results. In LCPD group, there was no revision during follow-up period. All stems and cups were survived without osteolysis or loosening at last follow-up. HHS increased significantly from 70.9±12.9 point to 97.4±5.4 point (p<0.001). LLD decreased significantly from 2.0±1.2 cm to 0.2±0.9 cm. (p<0.001). Fourteen intraoperative femoral cracks occurred. One patient showed peroneal nerve palsy after surgery. There was one patient with deep vein thrombosis without pulmonary embolism. In ONFH group, there was also no revision during follow-up and all implant was radiologically stable without evidence of osteolysis or loosening. HHS increased significantly from 44.9±21.4 point to 96.6±4.6 point (p<0.001). LLD decreased significantly from 0.5±0.8 cm to 0.1±0.9 cm. There were 6 intraoperative femoral fractures. Also, there was 2 more postoperative periprosthetic fractures after trauma and 1 postoperative dislocation. Even the implant survival was not different between two groups, LCPD group showed higher rate of overall complication (p=0.04) and intraoperative femoral fracture (p=0.027) than ONFH group. Conclusion. Outcomes of Al-Al THA in patients with sequelae of LCPD were comparable to those in patients with ONFH clinically and radiologically. LLD was restored after THA without troublesome neurologic complication in both groups. Although high rate of intraoperative femoral crack was revealed in LCPD group, fracture union was achieved in all hips without stem loosening. As with ONFH, Al-Al THA may be a reliable treatment option for the patients with LCPD sequelae

Introduction. Metal on metal hip resurfacing (MoM HR) is attractive for young active patients. Patients with osteonecrosis of the femoral head (ONFH) are relatively young. HR can be an option of treatment, however, long-term stability of the femoral component is a concern because of the necrotic lesion in the femoral head. There is also a concern of ARMD for MoM implants. The purpose of this study is review a 10 year outcome of a consecutive patients with ONFH who underwent MoM HR. Methods. The subjects of this study were 30 hips of 26 patients with ONFH who underwent HR between 1998 and 2004. There were 21 hips of 18 males and 9 hips of 8 females. The average age at operation was 40 years (range, 20–63 years). 19 ONFHs were induced by steroid and 11 ONFHs were alcohol related. According to the Japanese Investigation Committee classification, there were 8 hips with Type C1 and 22 hips with Type C2. There were 16 hips in stage 3A, 7 hips in Stage 3B, and 7 hips in Stage 4. Operation was performed through a posterior approach. A fragile necrotic bone was curettage thoroughly and the defect was filled with cement. Results. The average Harris hip score improved from 61 preoperatively to 97 at the final follow-up. The average radiographic inclination of the cup was 43 degrees (34–54 degrees) and the average anteversion was 12 degrees (4– 22 degrees). There was no dislocation. One hip had a late hematogenous infection at 9 years after surgery. Two hips of two patients with alcoholic ONFH had a mechanical loosening of the femoral component at 10 year and 13 years after surgery. The survivorship with revision for aseptic loosening as the endpoint was 96% at 10 years. There was no ARMD by ultrasound echo screening. There was no stress shielding of the femur at the final radiographic examination. Conclusion. Our over 10 year results of MoM HR for ONFH showed a high Harris hip score without dislocation. Although this series included the initial learning curve of the HR procedure, the survivorship with revision for aseptic loosening as the endpoint at 10 years was high. There was no ARMD by ultrasound echogram. MoM HR is a good option of treatment for ONFH

Post-traumatic osteonecrosis of the femoral head (ONFH) is a major complication of femoral neck fractures that require numerous solutions. The purpose of the current study is to investigate the effects of platelet-rich plasma (PRP) incorporated autologous granular bones graft for the treatment of pre-collapse stages (ARCO stage II-III) of post-traumatic ONFH. A total of 46 patients were eligible and enrolled into the study. 24 patients were treated with core decompression and PRP incorporated autologous granular bones graft (treatment group: 9 females and 15 males, age range, 16–39 years), and 22 patients with core decompression and autologous granular bones graft (control group: 6 females and 16 males, age range, 18–42 years. During a minimum duration of follow-up of 36 months, multiple imaging techniques including X-ray and computed tomography (CT) scanning were used to evaluate the radiological results, and Harris hip score (HHS) and the visual analogue scale (VAS) were chosen to assess the clinical results. Both treatment group and control group had a significant improved HHS (P < 0.001). The minimum clinically important difference (MCID) for HHS was reached in 91.7% of treatment group and 68.2% of control group (P = 0.0449). HHS in treatment group was significantly higher than control group at the last follow-up (P = 0.0254). VAS score was significantly declined in treatment group when compared with control group (P = 0.0125). Successful clinical results were achieved in 21 of 24 patients (87.5%) in treatment group compared with 13 of 22 patients (59.1%) in control group (P = 0.0284). Successful radiological results were achieved in 19 of 24 patients (79.2%) in treatment group compared with 11 of 22 patients (50%) in control group (P = 0.0380). The survival rates using requirement for further hip surgery as an endpoint were higher in treatment group in comparison to control group (P = 0.0260). The PRP incorporated autologous granular bones graft is a safe and effective procedure for the treatment of pre-collapse stages (ARCO stage II-III) of post-traumatic ONFH

Objectives. The purpose of the present study was to describe the long-term results of THA for ONFH in patients with SLE. Methods. From 1994–2001, 18 cementless THAs (14 SLE patients) were included in the present study. Four hips (3 patients) were lost to follow-up. The remaining 14 hips (11 patients) were available for evaluation. The mean follow-up period was 13.1(range, 10.0–16.4) years. The follow-up rate was 77.8%. The mean age at the time of surgery was 35.2 (range, 27.4–51.0) years. Results. Mean preoperative Harris Hip Score was 37.4 (range, 17.1–63.1) points, which improved to 94.5 (range, 73.9–100) points at final follow-up. Two hips had dislocation and were treated successfully with closed reduction. No patient in this study group had deep venous thrombosis or pulmonary embolism. One hip had peroneal nerve palsy. No superficial or deep wound infection was observed. Two hips of 2 patients required reoperation due to dislodgement of a polyethylene insert. With revision of the acetabular component for any reason considered to be a failure, the 10-year survival rate was 93% (95% CI, 0.79–1). Conclusion. We have reported the long-term results of THA for ONFH with SLE. Although several reports have noted that the results of THA for ONFH are less favourable than those for osteoarthritis, the long-term results of THA for ONFH with SLE were acceptable. THA is an acceptable option for patients with advanced-stage or an extended region of ONFH

Background. The short stem prosthesis showed good results in patients with primary osteoarthritis. However, there were a few studies about the short stem THA in patients with osteonecrosis of the femoral head (ONFH). Objective. To evaluate the clinical and radiographic results of the short stem THA in patients with ONFH. The authors hypothesized that the short stem THA would be a promising procedure for patients with ONFH. Material and Method. The authors reviewed 120 osteonecrotic hips in 93 patients who underwent THA with Metha® short stem from November 2010 to February 2013. The appearance of bone trabeculae development and radiolucent line was reviewed using Gruen's classification. The Harris hip score (HHS) was recorded at 6, 12, 24 and 36 months postoperative for evaluating the clinical results. Results. The mean age of patients was 44.4 years (18–68) with the mean BMI of 22.7 (15.1–32.5, SD 3.5). The average follow-up period was 29.2 months (20–47). The mean HHS was significantly improved from 43.9 (22.7–74, SD 7.7) preoperatively to 97.7 (85.9–100, SD 2.7) at 6 months postoperatively (p<0.01). The radiographic change around the stems showed bone trabeculae development at zone 1 (77 cases)(64.2%), 2 (27 cases)(22.5%), 3 (106 cases)(88.3%), 6 (120 cases)(100%) and 7 (115 cases)(95.8%). There was 1 case (0.8%) of 5 mm subsidence and the radiolucent line was observed in zone 1. There were 6 cases (5%) of intraoperative femoral fractures and were treated with cerclage wires, no further subsidence was observed. There was 1 case (0.8%) of distal stem perforation which had stable bone ingrowth. No revision was required. Conclusion. The clinical and radiographic results of the short stem THA in patients with ONFH are generally satisfactory. Its design enables preservation of the bone stock and the bone trabeculae appear to confirm the assumption of proximal force transmission. The authors believe that the short stem THA is a promising procedure for patients with ONFH

Introduction. The pathophysiology of osteonecrosis of femoral head (ONFH) is uncertain for most cases with speculation of vascular impairment and changes in cell biology due to multi-factorial etiologies including corticosteroid, alcohol, smoking, trauma, radiation or caisson disease and genetic. Extracorporeal shockwave therapy (ESWT) began with an incidental observation of osteoblastic response pattern during animal studies in the mid-1980 that generated an interest in the application of ESWT to musculoskeletal disorders. The mechanism of shockwave therapy is not fully understood but several reports showed better clinical outcomes and promoted bone remodelling and regeneration effect of the femoral head after ESWT in ONFH. Therefore, we compared the clinical results of the use of extracorporeal shock wave therapy (ESWT) on the patients with ONFH in radiographic staging. Methods. We evaluated 24 patients with 32 hip joints diagnosed ONFH treated with ESWT from 1993 to 2012. Average follow-up period was 27 months, and patients were average 47.8 aged. Association Research Circulation Osseous (ARCO) staging system was used to grade radiographic stage before treatment. All the patients were divided to two groups; group 1 (ARCO stage I,II), group 2 (ARCO stage III). Comparative analysis was done between two groups with visual analogue scale (VAS) score and Harris hip score (HHS) at pre-treatment, 3, 6, 12 and 24 months after treatments. The failure was defined when radiographic stage was progressed or arthroplasty surgery was needed due to clinical exacerbation. Results. Two groups showed all clinical improvements with VAS scoring at final follow-up (group 1: mean 6.3 to 1.6, p < 0.001; group 2: mean 7.1 to 3.3, p < 0.001). With HHS, group 1 showed a significant improvement from 64.4 to 95.4 (p < 0.001), while no significance in group 2 (p = 0.280). At final-follow-up, 3 hips of group 1 and 1 hip of group 2 showed radiographic improvement, but 2 patients were performed total hip arthroplasty due to persistent pain and dysfunction. Discussion and Conclusion. ESWT could be considered as an alternative option before surgical treatment in patients not only with early stage of ONFH but also with mid stage

Introduction. The natural history of osteonecrosis of the femoral head (ONFH) is not cleanly understood, but most of them progresse to the joint destruction and requires total hip replacement arthroplasty. There are several head preserving procedure, but no single therapeutic method proved to be effective in preventing progression of the disease. The possibility has been raised that implantation of bone marrow containing osteogenic precursors may be effective in the treatment of this disease. However, there are no long-term follow-up results of cell therapy for ONFH. AS far as we know, there are no reports about bone graft and cell therapy for ONFH. Therefore, we performed a prospective clinical and radiological evaluation on ONFH treated with core decompression combined with autoiliac bone graft and an implantation of autologous bone marrow cells as a therapeutic method of ONFH. Materials and Methods. Sixty-one hips in 52 patients with ONFH were included in this study. The average follow-up of the patients was 68 (60∼88) months. The necrotic lesions were classified according to their size and location, and we compared the results. Results. At the last follow-up, the rate of excellent or good results was 80% (12/15 hips) in the small lesion group, 65% (17/26 hips) in the medium size group, and 28% (6/20 hips) in the large size group. The procedures were a clinical success in 4 of 5 hips(80%) with stage I, 23 of 35 hips (65.7%) with Stage II and 7 hips of 18 hips(38.9%) with stage III and 1 of 3 hips(33.3%) with stage IV. Among the 20 cases with large sized necrotic lesions, 17 cases were laterally located and this group showed the worst outcome with 13 hips (76.5%) having bad or failed clinical results. Conclusions. The outcome of cancellous bone grafting combined with implantation of autologous bone marrow cells differed depending on the size and location of the lesion. The patients who have a large sized lesion or medium sized lateral located lesion would not be considered as a good candidate for head preserving procedure. However for the medium sized lesions, this procedure showed a competent clinical result against other head preserving procedures

Background. Core decompression (CD) is effective to relieve pain and delay the advent of total hip arthroplasty (THA) for osteonecrosis of the femoral head (ONFH). However, the influence of CD on the subsequent THA has not been determined yet. Methods. Literatures published up to and including November 2018 were searched in PubMed, Embase and the Cochrane library databases with predetermined terms. Comparative studies of the clinical outcomes between conversion to THA with prior CD (the Prior CD group) and primary THA (the Control group) for ONFH were included. Data was extracted systematically and a meta- analysis was performed. Results. Overall, five retrospective cohort studies with 110 hips in the Prior CD group and 237 hips in the Control group were included and all the studies were of high quality in terms of Newcastle-Ottawa Scale. No difference in the rate of revision between the two groups showed (RR=1.92, P=0.46) after a minimal two-year follow-up. Postoperative Harris Hip Score were similar between the two groups in all the five studies. Two groups went through similar blood loss (P=0.38). But the operative time in the Prior CD group with tantalum rob was longer than that in the Control group (P=0.006, P<0,001, respectively in two papers). Moreover, intraoperative fracture and osteolysis or radiolucent lines were more likely to occur in the Prior CD group, though there is not statistical difference (RR=7.05, P=0.08; RR=3.14, P=0.05, respectively). Conclusion. The present evidence indicated that prior CD has no inferior effect on the survivorship nor hip scores to the subsequent THA. The operative time in the Prior CD group with tantalum rob was longer than that in the Control group. Attention should also be paid on possible more intraoperative fracture and postoperative osteolysis or radiolucent lines. For any figures or tables, please contact authors directly

Purpose. The purpose of this study is to know the peri-operative morbidity, clinical and radiographical outcomes of conversion THA from failed transtrochanter rotational osteotomy (TRO). Patients and methods. From 2003 January to 2009 January, there were 18 hips(18 patients) who underwent conversion THA from TRO for osteonecrosis of the femoral head (ONFH) (Group I). The mean duration from TRO to conversion THA was 2.6 years. We made a matched control group of 18 primary THA for ONFH (Group II) and we evaluated perioperative morbidity and complications in each group. For the clinical evaluation, we checked Harris hip score (HHS) and WOMAC score. For the radiographical evaluation, we evaluated implant position, stability and osteolysis. Results. There was no significant differences in operation time, blood loss, hospital stay between two groups. In clinical results, there was no significant difference in postoperative HHS (p=0.986), but there was significant difference in postoperative WOMAC score. There was more significant postoperative internal rotation limitation in the Group II (p<0.001). In radiographical evaluation, there was no significant difference between two groups, except the preoperative leg length discrepancy (p=0.015). Conclusion. According to our study, there was no significant difference between conversion THA after TRO and primary THA in terms of perioperative morbidity and radiographical out come. But primary THA showed better postoperative internal rotation and better WOMAC score than conversion THA after previous TRO for ONFH

Background/Purpose. Total hip arthroplasties (THAs) with ceramic bearings are widely performed in young, active patients and thus, long-term outcome in these population is important. Moreover, clinical implication of noise, in which most studies focused on ‘squeaking’, remains controversial and one of concerns unsolved associated with the use of ceramic bearings. However, there is little literature regarding the long-term outcomes after THAs using these contemporary ceramic bearings in young patients. Therefore, we performed a long-term study with a minimum follow-up of . 1. 5 years after THAs using contemporary ceramic bearings in young patients with osteonecrosis of the femoral head (ONFH) less than fifty. Materials and Methods. Among sixty patients (71 hips) with a mean age of 39.1 years, 7 patients (7 hips) died and 4 patients (4 hips) were lost before 15-year follow-up. The remaining 60 hips were included in this study with an average follow-up period of 16.3 years (range, 15 to 18). All patients underwent cementless THA using a prosthesis of identical design and a 28-mm third-generation alumina head by single surgeon. The clinical evaluations included the modified Harris hip score (HHS), history of dislocation and noise around the hip joint: Noise was classified into squeaking, clicking, grinding and popping and evaluated at each follow-up. Snapping was excluded through physical examination or ultrasonography. Radiographic analysis was performed regarding notching on the neck of femoral component, loosening and osteolysis. Ceramic fracture and survivorship free from revision were also evaluated. Results. The mean Harris hip score improved from 55.3 to 95.5 points (range, 83 to 100) at the time of the final follow-up. Seventeen patients (34.7%) reported noise around the hip joint: “squeaking” in one and “clicking” in 16 patients. Notching on the neck of femoral component suggesting impingement between neck and ceramic liner was demonstrated in 9 hips (15%) at average of 6.9 years postoperatively and located at 2 to 3.5 mm distal to edge of ceramic head. Although no chip fracture of ceramic ‘liner’ occurred, notching was associated with “clicking” sound (p<0.01). One patient who reported clicking sound underwent a revision THA because of ceramic ‘head’ fracture. Loosening, osteolysis or dislocation was not observed in any hip and survivorship free from revision at 5 years was 98%. Conclusion. Cementless THAs using 28-mm contemporary alumina ceramic head demonstrated excellent long-term outcome in young, active patients with ONFH. Despite this encouraging result, however, we remain concerned about ‘clicking’ sound, because we did observe it associated with notching on the neck of stem. Acknowledgement. This work was supported by Institute for Information & communications Technology Promotion (IITP) grant funded by the Korea government (MSIP) (#B0101-14-1081)