Aims. The purpose of this study was to examine whether leg-length discrepancy (LLD) following unilateral total hip arthroplasty (THA) affects the incidence of contralateral head collapse and subsequent THA in patients with bilateral osteonecrosis, and to determine factors associated with subsequent collapse. Patients and Methods. We identified 121 patients with bilateral non-traumatic osteonecrosis who underwent THA between 2003 and 2011 to treat a symptomatic hip, and who also exhibited medium-to-large lesions (necrotic area ≥ 30%) in an otherwise asymptomatic non-operated hip. Of the 121 patients, 71 were male (59%) and 50 were female (41%), with a mean age of 51 years (19 to 71) at the time of initial THA. All patients were followed for at least five years and were assessed according to the presence of a LLD (non-LLD vs LLD group), as well as the LLD type (longer non-operated side vs shorter non-operated side group). Results. Overall, 68 hips (56%) became painful and progressed to collapse at a mean of 2.6 years (0.2 to 13.8), resulting in 59 THAs (49%). The five-year collapse-free survival rate for the non-LLD group was 59% (95% confidence interval (CI) 46.8 to 71.8) compared with 45% (95% CI 32.9 to 57.5) for the LLD group (p = 0.036), and 66% (95% CI 55.2 to 77.2) for the longer non-operated side group compared with 32% (95% CI 19.1 to 44.9) for the shorter non-operated side group (p < 0.001). Multivariate regression analyses found that large lesions had a higher risk of collapse than medium-size lesions (odds ratio (OR) 4.19, 95% confidence interval (CI) 1.69 to 10.38; p = 0.002). Meanwhile, patients with a LLD < 3 mm (OR 0.20, 95% CI 0.08 to 0.52; p = 0.001) or a longer non-operated leg (OR 0.11, 95% CI 0.04 to 0.28; p < 0.001) after THA were less likely to experience a subsequent collapse. Conclusion. We found that LLD may be a modifiable risk factor for femoral head collapse. Minimizing LLD and particularly avoiding a shorter non-operated limb after THA may lead to a lower risk of collapse of the asymptomatic hip in patients with bilateral non-traumatic osteonecrosis. Cite this article: Bone Joint J 2019;101-B:303–310

Aims

The present study investigated the five-year interval changes in pseudotumours and measured serum metal ions at long-term follow-up of a previous report of 28 mm diameter metal-on-metal (MoM) total hip arthroplasty (THA).

Femoral head collapse due to avascular necrosis (AVN) is a relatively rare occurrence following intertrochanteric fractures; however, with over thirty-thousand intertrochanteric fractures per year in England and Wales alone, and an incidence of up to 1.16%, it is still significant. Often patients are treated with a hip fixation device, such as a sliding hip screw or X-Bolt. This study aimed to investigate the influence of three factors on the likelihood of head collapse: (1) implant type; (2) the size of the femoral head; and (3) the size of the AVN lesion. Finite element (FE) models of an intact femur, and femurs implanted with two common hip fixation designs, the Compression Hip Screw (Smith & Nephew) and the X-Bolt (X-Bolt Orthopaedics), were developed. Experimental validation of the FE models on 4. th. generation Sawbones composite femurs (n=5) found the peak failure loads predicted by the implanted model was accurate to within 14%. Following validation on Sawbones, the material modulus (E) was updated to represent cancellous (E=500MPa) and cortical (E=1GPa) bone, and the influence of implant design, head size, and AVN was examined. Four head sizes were compared: mean male (48.4 mm) and female (42.2 mm) head sizes ± two standard deviations. A conical representation of an AVN lesion with a lower modulus (1MPa) was created, and four different radii were studied. The risk of head collapse was assessed from (1) the critical buckling pressure and (2) the peak failure stress. The likelihood of head collapse was reduced by implantation of either fixation device. Smaller head sizes and greater AVN lesion size increased the risk of femoral head collapse. These results indicate the treatment of intertrochanteric fractures with a hip fixation device does not increase the risk of head collapse; however, patient factors such as small head size and AVN severity significantly increase the risk

Conversion of failed femoral components of total hip resurfacing to conventional hip replacement is reportedly a straightforward procedure. There is little published to qualify this and what is available suffers from small study numbers and various combinations pre and post-operative implants. Between 1997 and 2002, the Oswestry Outcome Centre prospectively collected data on 5000 Birmingham Hip Resurfacings (BHRs) performed by 141 surgeons, at 87 hospitals. To date 4526 have survived, 135 died and 165 are lost to follow-up. 174 have been revised, of which 60 were failures of the femoral component. We reviewed modes of failure and post-revision clinical outcomes in this sub-group. Isolated femoral component failure accounted for 60 hips (1.2%). 28 femoral neck fractures, 14 femoral head collapses, 13 femoral component loosenings, 3 avascular necroses (AVN), 1 femoral loosening followed by fracture and 1 dislocation. Mean time to revision surgery was 2.6 years (1.8 years for neck fracture; 3.4 years femoral loosening, head collapse and AVN). All acetabular components were left in situ. At revision surgery 25 cemented, 25 uncemented and 10 unknown femoral prostheses were used with 56 BHR modular heads, 2 custom-made Exeter heads and 2 Thrust Plate heads. 47 patients completed outcome scores post-revision surgery. Median modified Harris Hip Score was 82 (IQ range=63–93) and Merle d’Aubigne score was 14 (IQ= 9.5–15) at a mean follow up of 3.9 years post-revision. The 4526 surviving resurfacings had a median hip score of 96 (IQ=87–100) p≤4.558x10-8 and median Merle score of 17 (IQ=14–18) p≤1.827x10-7. Mean 7.0 years follow up. There was no difference in outcomes between cemented and un-cemented revision components nor were there differences between fractured neck of femur and femoral loosening, head collapse or AVN. Following revision of the femoral component to a conventional hip replacement, function is significantly worse than surviving resurfacings

Introduction: Conversion of failed femoral components of total hip resurfacing to conventional hip replacement is reportedly a straightforward procedure. There is little published to qualify this and what is available suffers from small study numbers and various combinations pre and post-operative implants. Method: Between 1997 and 2002, the Oswestry Outcome Centre prospectively collected data on 5000 Birmingham Hip Resurfacings (BHRs) performed by 141 surgeons, at 87 hospitals. To date 4526 have survived, 135 died and 165 are lost to follow-up. 174 have been revised, of which 60 were failures of the femoral component. We reviewed modes of failure and post-revision clinical outcomes in this sub-group. Results: Isolated femoral component failure accounted for 60 hips (1.2%). 28 femoral neck fractures, 14 femoral head collapses, 13 femoral component loosenings, 3 avascular necroses (AVN), 1 femoral loosening followed by fracture and 1 dislocation. Mean time to revision surgery was 2.6years (1.8years for neck fracture; 3.4years femoral loosening, head collapse and AVN). All acetabular components were left in situ. At revision surgery 25 cemented, 25 uncemented and 10 unknown femoral prostheses were used with 56 BHR modular heads, 2 custom-made Exeter heads and 2 Thrust Plate heads. 47 patients completed outcome scores post-revision surgery. Median modified Harris Hip Score was 82 (IQ range=63–93) and Merle d’Aubigne score was 14 (IQ= 9.5–15) at a mean follow up of 3.9years post-revision. The 4526 surviving resurfacings had a median hip score of 96 (IQ=87–100) p≥4.558x10-8 and median Merle score of 17 (IQ=14–18) p≥1.827x10-7. Mean 7.0 years follow up. There was no difference in outcomes between cemented and uncemented revision components nor were there differences between fractured neck of femur and femoral loosening, head collapse or AVN. Discussion: Following revision of the femoral component to a conventional hip replacement, function is significantly worse than surviving resurfacings

When patients present at an early age with osteoarthritis of the hip, there is usually an underlying predisposing cause. In men, a common cause is femoroacetabular impingement (FAI). This is evident as anterior neck osteophytes, with retroversion and varus alignment of the femoral head, most likely the result of subclinical slipped capital femoral epiphysis. The resulting femoroacetabular cam impingement causes degenerative osteoarthritis (OA) of the hip, at an earlier age than primary OA. Patients present in their 40s and 50s with advanced arthritis, and are faced with the prospect of a total hip arthroplasty. Women may experience this as well, but may present with early hip arthritis as a result of subclinical dysplasia or pincer FAI more often than their male counterparts. Hip resurfacing has several advantages over traditional total hip replacement for younger patients, especially men. These include bone preservation, less dislocation, thigh pain or leg length inequality, easier return to athletics, and easy revision on the femoral side. It is indicated in young, active patients. The resurfacing procedure realigns the femoral head on the native and resurfaces the arthritic joint. Anterior neck osteoplasty is performed. Head retroversion is corrected. This restores deep flexion, and eliminates forced external rotation in flexion. Hip resurfacing can be done through either an anterior or posterior approach, although the anterior approach gives easier access to the anterior femoral neck, and preserves the blood supply to the head. This may help prevent femoral neck fractures and late head collapse

Aims

Proximal humeral fractures are the third most common fracture among the elderly. Complications associated with fixation include screw perforation, varus collapse, and avascular necrosis of the humeral head. To address these challenges, various augmentation techniques to increase medial column support have been developed. There are currently no recent studies that definitively establish the superiority of augmented fixation over non-augmented implants in the surgical treatment of proximal humeral fractures. The aim of this systematic review and meta-analysis was to compare the outcomes of patients who underwent locking-plate fixation with cement augmentation or bone-graft augmentation versus those who underwent locking-plate fixation without augmentation for proximal humeral fractures.

Aims

Successful cell therapy in hip osteonecrosis (ON) may help to avoid ON progression or total hip arthroplasty (THA), but the achieved bone regeneration is unclear. The aim of this study was to evaluate amount and location of bone regeneration obtained after surgical injection of expanded autologous mesenchymal stromal cells from the bone marrow (BM-hMSCs).

Osteonecrosis of the femoral head is a complex pathologic process with many aetiological factors. Factors most often mentioned in the literature are mechanical disruption (hip trauma or surgery), steroid use, smoking, haemoglobinopathies and hyperlipidaemia. 1. Our case depicts a rare association of crack cocaine related to osteonecrosis of the femoral head which has never been reported in the available literature. Case Report: A 32 year old man was referred to our Orthopaedic clinic with right hip pain. He had a 9 pack-year history of cigarette smoking and had also smoked crack cocaine between ages 20 to 28; shortly after this the hip pain started. He denied antecedent injury. He had undergone a steroid injection into his right ankle abroad for swelling one year before referral, which was after onset of hip pain. MRI of his hip previously performed abroad had been normal. The patient had an indoor job and was otherwise fit and well. On examination he had reduced of movement in his right hip with 5–10 degrees of fixed flexion deformity. Plain radiography demonstrated cyst formation and sclerosis of both femoral heads. Repeat MRI confirmed bilateral osteonecrosis, worse on the right with risk of head collapse. The patient underwent bilateral core decompressions. Subsequent follow-up demonstrated a mobile patient with no need for arthroplasty and he was discharged after two years. Osteonecrosis is caused by the coagulation of the intra-osseous microcirculation leading to thrombosis formation and eventual reduction in osseous blood supply. Steroid use is associated with increased risk of osteonecrosis to the femoral head, however in these cases the patients often undergo either direct local or systemic infiltration of steroid. In this case steroid was administered after symptoms began to a far distant site and therefore cannot be the cause. Cigarette smoking is also known to cause osteonecrosis. Our patient had smoked cigarettes for fourteen years without problems, and it was after he ceased to smoke crack cocaine that his symptoms began. Cocaine blocks voltage-gated sodium-channels causing vasospasm. It is known to cause nasal and facial bone osteonecrosis due to its common intranasal method of delivery. We postulate that in this case crack cocaine was a synergistic factor towards development of femoral head osteonecrosis

Hip resurfacing, like other orthopaedic procedures, depends for its success upon the confluence of three factors: a well-designed device, implanted using good technique, in a properly selected patient. Cleveland Clinic has had good mid-term results in more than 2,200 patients using the Birmingham device since its FDA approval in 2006. These results are quite similar to other reported series from many centers around the world. All surgery was performed using an anterolateral approach. Males accounted for 72% of the patients, and the average age was 53 years (12‐84). More than 90% of the patients had a diagnosis of osteoarthritis, and femoroacetabular impingement was the predominant pathology. The average component head size in males was 51mm, and in females 45mm. Complications were few, with no dislocations, no femoral loosening, one socket loosening, one head collapse, 2 femoral neck fractures, and 2 deep infections. There were two patients with metallosis, one due to component malposition, and one in a small, dysplastic female. There were no destructive pseudotumors. Overall survivorship at up to 8 years was more than 99%. Survivorship in young males, under age 50 with OA was 100%. New mushroom templates for head size are described. Additional imaging recommendations including a standing lateral of the pelvis, and a CT scan for femoral anteversion may be helpful in patient selection

We report our early experience with distracting external fixation used to offload the hip after avascular necrosis (AVN) of the femoral head secondary to severe slipped upper femoral epiphysis (SUFE). A case series of five patients treated in a tertiary centre is reported. Electronic case records and radiographs were reviewed. Data recorded included demographics, initial presentation, timing of head collapse, timing and duration of distraction and outcome including referral to adult arthoplasty services. Mean age at presentation was 12 years (range 12–15). 4 were females. Initial treatment in 4 cases was a delayed cuneiform osteotomy and pinning, one patient underwent serendipitous reduction and percutaneous pinning. Mean duration to initial surgery was 10 days (range 5–16). All patients had femoral head collapse at a mean of 148 days from time of presentation. 2 patients required backing out of screws due to intra-articular protrusion. All patients underwent distraction at a mean 193 days from presentation. Average distraction achieved was 10 mm and duration of application was 125 days (range 91–139). All patients experienced improvement or resolution of pain but persistence of poor function, characterised by fixed adduction and limb length discrepancy. 3 patients were referred to adult arthroplasty services. This may be an effective treatment option for pain associated with AVN post SUFE. However, in our experience normal anatomy and function of the hip is not restored if performed after collapse of the femoral head. Consideration should be given to application of the distractor either at the time of initial fixation or prior to femoral head collapse. Authors believe that timing of the application of the distractor is critical for a successful outcome and recommend a prospective study with large numbers

Introduction. Most metal-on-metal hip resurfacing implants currently being used worldwide utilize bone ingrowth fixation on the acetabular side, but cement fixation remains the standard method of fixation on the femoral side. Our hypothesis is that bone ingrowth fixation of a fully porous-coated component is superior to cement fixation of the femoral hip resurfacing component. Methods. From March 2007 to Jan 2009, 429 consecutive metal-on-metal hip resurfacing arthroplasties were performed by a single surgeon in 396 unselected patients using Biomet uncemented femoral and acetabular components. All of these were at least 5-years postop. Three patients died with causes unrelated to their hip arthroplasty. The three most common primary diagnoses were osteoarthritis in 318 (74%) cases, dysplasia in 66 (15%) hips, and osteonecrosis in 19 (4%) hips. The average size of the femoral component was 50 ± 4 cm. All pre-operative, intra-operative, and post-operative data were prospectively collected and entered into our database for review. All patients are allowed unrestricted activity including impact sports after 6 months. Results. Metal ion test results were available for 78% of patients. There were 14 (3.2%) failures identified at the time of this study. There were six (1.4%) early femoral failures (4 femoral neck fractures, 2 head collapses prior to 2 years), four loose acetabular components (one failed at 2 months postoperatively; three after 2 years), two (0.5%) adverse wear related failures (AWRF; metal ion levels ≥10 ug/L, AIA> 50. 0. , metalosis), one intertrochanteric fracture; and one failure due to subluxation. There were no cases of failure of femoral ingrowth or late femoral loosening. For the non-failed group, the average post-operative HHS score was 97±9 at their latest follow-up; the average UCLA Activity Score was 7±2. Survivorship was 96.7% at 5 years (all failures). Femoral survivorship was 98.4%. The AWRF rate was 0.5% at 5 years. No femoral failures occurred after one year postop up to 7 years. Conclusions. Bone ingrowth fixation with a fully porous femoral component in hip resurfacing remains highly durable beyond 5 years. Femoral ingrowth is more reliable than acetabular ingrowth. No cases of femoral loosening have been encountered up to 7 years post implantation. AWRF is rare (0.5% at 5 years) and is caused by acetabular component malposition

Purpose. Proximal femoral osteotomy is an attractive joint preservation procedure for osteonecrosis of the femoral head. The purpose of this study was to investigate the cause of failure of proximal femoral osteotomy in patients with osteonecrosis of the femoral head. Patients and Methods. Between 2008 and 2014, proximal femoral osteotomy was performed by one surgeon in 13 symptomatic hips. Ten trans-trochanteric rotational osteotomies (anterior: 7, posterior: 3) and 3 intertrochanteric curved varus osteotomy were performed. Of the patients, 9 were male and 1 was female, with a mean age at surgery of 36.9 years (range, 25–55 years). The mean postoperative follow-up period was 38 months (range, 12–72 months). Three patients (4 hips) had steroid-induced osteonecrosis, and 7 (9 hips) had alcohol-associated osteonecrosis. At 6 postoperative weeks, partial weight bearing was permitted with the assistance of 2 crutches. At more than 6 postoperative months, full weight bearing was permitted. Patients who had the potential to achieve acetabular coverage of more than one-third of the intact articular surface on preoperative hip radiography, computed tomography, and magnetic resonance imaging were considered suitable for this operation. A clinical evaluation using the Japanese Orthopaedic Association (JOA) scoring system and a radiologic evaluation were performed. Clinical failure was defined as conversion to total hip arthroplasty (THA) or progression to head collapse and osteoarthritis. The 13 hips were divided into two groups, namely the failure and success groups. Results. The mean preoperative JOA score was 59 points. The score in the success group (7 hips) improved to 89 points at the time of final follow-up. In the failure group (6 hips), 5 hips were converted to THA because of progression to secondary collapse or osteoarthritis in a mean postoperative period of 35 months (range, 24–51 months). After converting to THA, good clinical and radiographic results were achieved, except in 1 patient who had incomprehensible severe pain around the affected hip. Advanced osteoarthritis was observed in 1 hip awaiting THA. Various factors cause failure of proximal femoral osteotomy, such as difficulty in controlling the underlying disease with less than 10 mg of steroid (Fig. 1), overuse of the affected hip within 6 postoperative months without the physician's consent, vascular occlusion after total necrosis of the femoral head as a result of damage to the nutritional vessel during or after the operation, and incorrect judgement of the indication of the operation and the extent of the intact load-bearing area. Conclusion. We think that full weight bearing should be permitted postoperatively only after more than 6 months, and heavy work and sport, only after more than 1 year. Efforts should be made to improve surgeons' skill in proximal femoral osteotomy and accurate judgement of imaging data. For steroid-induced osteonecrosis of the femoral head, proximal femoral osteotomy is an acceptable procedure for relieving pain if the underlying disease can be controlled with not more than 5 mg of steroid

Aims

Hyaline cartilage has a low capacity for regeneration. Untreated osteochondral lesions of the femoral head can lead to progressive and symptomatic osteoarthritis of the hip. The purpose of this study is to analyze the clinical and radiological long-term outcome of patients treated with osteochondral autograft transfer. To our knowledge, this study represents a series of osteochondral autograft transfer of the hip with the longest follow-up.

Aims

Total hip arthroplasty (THA) is considered the preferred treatment for displaced proximal femoral neck fractures. However, in many countries this option is economically unviable. To improve outcomes in financially disadvantaged populations, we studied the technique of concomitant valgus hip osteotomy and operative fixation (VOOF). This prospective serial study compares two treatment groups: VOOF versus operative fixation alone with cannulated compression screws (CCSs).

Metal on metal hip resurfacing is increasing in popularity for the young, active patient. We present the results of a consecutive series from a single surgeon over a ten year period; 295 hip resurfacings (McMinn and Cormet; Corin, Cirencester, UK) with a minimum follow up of 2 years and a mean follow up of 4 years. There were 173 males with a mean age of 53.4 years and 121 females with a mean age of 50.3 years. Forty-six patients underwent bilateral resurfacings. All resurfacings were performed through a posterior approach. The aetiology in this group was primary OA in 75.9%, inflammatory arthritis in 6.1%, DDH in 6.1%, AVN in 4.7%, trauma in 4.7%, Perthes in 1.7% and SUFE in 0.7%. Patients were reviewed clinically and radiographically on an annual basis. Follow-up was available on 93% of patients. 94.2% of hips have survived and the mean Harris Hip Score is 87.5. Females had a higher failure rate (10.7%) than males (2.3%). There was no clear trend between patient age and failure rate. The highest failure rate (33.3%) was seen in patients with DDH whilst only 4.5% of patients with OA failed. One patient with AVN failed but no failures occurred in patients with inflammatory arthritis, trauma, Perthes or SUFE. Failures occurred due to cup loosening (2.0%), neck fractures (1.7%), head loosening (1.0%), head collapse (0.3%), infection (0.3%) and pain (0.3%). The five patients who suffered neck fractures were symptomatic within 3 months of surgery. We remain cautiously optimistic about the medium term results of hip resurfacing. Careful patient selection is important and caution should be taken in females and patients with DDH

The results of displaced three part fracture of the proximal humerus treated by retro grade nailing +/− cannulated cancellous screws for fixation of the greater tuberosity was analysed. Displaced three part fractures of the humerus are unstable and difficult to fix. Different methods of operative treatment available for this type of fracture are Kirschner wires, tension band wiring, hemiarthroplasty and open reduction and internal fixation with plate and screws. The Halder Humeral Nail was introduced through the olecranon fossa into the head of the humerus, to stabilize the neck of humerus fracture. The displaced greater tuberosity was reduced with a minimal stab incision and fixed with cannulated screws. Compared to other open procedures the proximal exposure was minimal. 47 Patients with displaced three part proximal humeral fractures have been surgically treated since January 1995. 22 Were treated with proximal screws and 25 without proximal screw fixation. There were 32 females and 15 males. The average age was 67.68 years. Early passive movements were encouraged in the shoulder. Pain was relieved in almost all the patients. 41 Fractures united. 3 Patients had a malunion, 2 had humeral head collapse, and 1 developed AVN of the humeral head. The authors concluded that displaced three part proximal humeral fractures can be treated using the Halder Humeral Nail, and that this is a simple method of treatment which avoids major surgical exposures

First described in 1910, Legg Calve Perthes disease is considered to be a complication of osteonecrosis of the femoral head-affecting children between the ages of 2 and 12. Treatment has centred on containment, surgical and non-surgical in the hope that keeping the femoral head covered by acetabulum that it will remodel and maintain congruency with the acetabulum. We know from previous studies that deformities of the femoral head increase the risk of development of arthritis in later life and that the shape of the femoral head is the only alterable parameter in the development of this early onset arthritis. During the natural history of the disease, once the central part of the femoral head collapses the integrity of the femoral head is reliant on the support of the lateral and medial columns. These columns then collapse altering the shape of the femoral head. We induced LCPD in the femoral heads of twenty skeletally immature rabbits and buttressed the central column of the femoral head in twelve. These treated rabbits had cement, bone graft or bone paste inserted through a drill hole that extended into the centre of the femoral head. The rabbits were then recovered and x-rayed at six weeks. All the rabbits had evidence of varying degrees of head collapse radiologically. Once the rabbits reach skeletal maturity in March, they will be euthanised and their femoral heads examined histologically and radiologically to determine the effects of central column enhancement by each of the three substances

Hip arthroscopy is a well-established technique becoming more and more an indispensable tool in institutions specialized in hip diseases. Several surgeons around the world have developed and refined the proper instruments and the surgical technique for this operation. By now, the indications have been well formulated for both diagnostic and interventional purposes. My personal experience is of 98 hip arthroscopies performed in the last 6 years. Most common preoperative indication has been chronic hip pain after failure of conservative treatment. Other indications or arthroscopic findings have been: labral pathology, hip dysplasia, synovial chondromatosis, initial osteoarthritis, calcium pyrophosphate disease, ligamentum teres damage, chondral damage, post-traumatic loose bodies, avascular necrosis, sepsis, villonodular synovitis. More recent, indications for hip arthroscopy are staging of avascular necrosis of the femoral head and shaving of polyethylene debris after total hip replacement. Contraindications to arthroscopy include recent fracture of the pelvis osteoarthritis with osteophytosis, AVN with head collapse. Hip arthroscopy can facilitate both comprehensive access to and treatment of an evolving series of conditions that affect the hip joint. Purpose of this presentation is to show the surgical technique and present the results obtained. New indications and potential future evolutions are also discussed

Purpose: Surface replacement arthroplasty is being increasingly offered as the treatment of choice to young and active patients with hip arthritis with proposed advantages including bone conservation and better functional outcome. Excellent outcome has been reported in the few recent short-term clinical series of surface replacement arthroplasty. However they have an inbuilt patient selection bias. There are no direct prospective randomized studies comparing the newer generation of surface replacement arthroplasty with conventional total hip arthroplasty. Our study addresses this issue. Method: 210 hips in 194 patients were randomized to receive either an uncemented total hip arthroplasty or a hybrid metal-on-metal surface replacement arthroplasty. Complications, functional outcomes, along with patient satisfaction and radiographic evaluation were compared at a minimum of two years follow up. Results: Patients in both groups demonstrated a very high satisfaction rate and achieved similar functional scores. Four dislocations occurred in the THA group (one needing acetabular cup revision) and none in the SRA group. There were no femoral neck fractures in the surface replacement arthroplasty group. However, two surface replacement arthroplasty cases underwent revision for late head collapse and one needed a femoral neck osteoplasty for persisting femoro-acetabular impingement. Better biomechanical restoration was attained with surface replacement arthroplasty. All the components were considered to be stable after an average follow up of 45 months. Conclusion: Although surface replacement arthroplasty of the hip offer similar patient satisfaction, functional outcome and complication rate as an uncemented total hip arthroplasty in a young and active group of patients, different complications were associated to each procedure. Better patient selection could avoid some of the complications in the surface replacement arthroplasty group. One main advantage that remains for the surface arthroplasty technique it is the proximal femoral bone stock preservation. However, long term survival analysis is necessary to determine the true advantage of these implants over total hip arthroplasty