Introduction: Peri-prosthetic fractures following hip resurfacing arthroplasty are difficult fractures to treat. The surgeon is faced with the task of either attempting to fix the fracture if feasible or revise the resurfacing implant to a conventional total hip replacement. Method & Results: Here we report of a novel way of fixing a peri-prosthetic fracture following resurfacing hip arthroplasty using Polyaxial locking plate fixation. A 53 year old man sustained a intertrochanteric fracture below his resurfacing metal on metal hip prosthesis following a fall. He had his hip resurfaced 3 years back for osteoarthritis in another hospital. He underwent surgery to fix the fracture using a polyaxial locking plate with no post-operative complications. He was mobilised non-weight bearing for the initial six weeks and weight bearing as tolerated thereafter. He went on to union and was moblising without any problems in three months time. His follow-up x-rays at 8 months showed fracture healed with no evidence of prosthesis problems. Discussion: There are various methods of treating a periprosthetic fracture of a well fixed resurfaced hip implant. The two types of management are open reduction and internal fixation and revision to a stemmed hip implant. These fractures can be fixed with cannulated hip screws, blade plate device or plating with screws avoiding the stem of the resurfacing prosthesis. We used the polyaxial locking plate device with good result thereby avoiding the need for revision surgery with its attendant risks. Using this implant is a useful alternative for these fracture patterns

Introduction: Femoral neck failure due to avascular necrosis (AVN) is one of the most significant complications following resurfacing hip arthroplasty. It is likely that the surgical approach is one of the factors influenc-ing the development of AVN. Positron emission tomography (PET) is the only form of imaging that allows visualisation of bone metabolic activity deep to a metal surface. Objectives: To establish the reliability and accuracy of PET using fluorine-18 to evaluate viability of the femoral head and neck after resurfacing hip arthroplasty. To assess the viability of ten proximal femora after Birmingham resurfacing hip arthroplasty via a modified lateral approach. Design: A convenience case series of ten patients taken from the first fifteen from one orthopaedic surgeon’s experience of Birmingham resurfacing hip arthroplasty. Setting: The PET unit of a major urban teaching hospital with a large academic orthopaedic department. Participants: Patients that had undergone unilateral Birmingham resurfacing hip arthroplasty via a modified lateral approach were asked to volunteer for the study. The main criterion for inclusion was ease of attendance for imaging. Intervention: Participants were given a single intravenous dose of 250MBq fluorine-18. After a period of 40 minutes uptake time, PET images of adjacent, sequential 10cm transverse sections including both acetabulae and proximal femora were obtained. Main Outcome Measures: Images were reconstructed to allow relative quantification of uptake between operated and non-operated femoral heads and necks. Results: PET imaging was successful in all subjects and demonstrated activity within the resurfaced femoral heads and femoral necks. No evidence of AVN was found. Conclusions: Static positron emission tomography using fluorine-18 is an accurate and reliable method of assessing femoral head and neck viability after resurfacing hip arthroplasty. No evidence of avascular necrosis was found in this initial series of patients that had undergone Birmingham resurfacing hip arthroplasty via a modified lateral approach

Correct positioning of the femoral component in resurfacing hip arthroplasty (RHA) is an important factor in successful long-term patient outcomes. Computer-assisted navigation (CAS) shows potential to improve implant positioning and possibly prolong survivorship in total hip and knee arthroplasty. The purposes of CAS systems in resurfacing the femoral head are to insert the femoral head and neck guide wire with greater accuracy and to help in sizing the femoral component, thus reducing the risk of notching of the head and neck junction. Several recent studies reported satisfactory precision and accuracy of CAS in RHA. However, there is little evidence that computer navigation is useful in the presence of anatomical deformities of the proximal femur, which is frequently observed in young patients with secondary degenerative joint disease. The purpose of this in-vitro study was to determine the accuracy of an image-free resurfacing hip arthroplasty navigation system in the presence of two femoral deformities: pistol grip deformity of the head and femoral neck junction and slipped upper femoral epiphysis deformity. An artificial phantom leg with a simulated hip and knee joint was constructed from machined aluminum. Implant-shaft angles for the guide wire of the femoral component reamer were calculated, in frontal and lateral planes, with both a computer navigation system and an electronic caliper combined with micro-CT. With normal anatomy we found close agreement between the CAS system and our measurement system. However, there was a consistent disagreement in both the frontal and lateral planes for the pistol grip deformity. Close agreement was found only on the frontal plane angle calculation in the presence of the slipped upper femoral epiphysis deformity, but calculation of the femoral head size was inaccurate. This is the first study designed to assess the accuracy of a femoral navigation system for resurfacing hip arthroplasty in the presence of severe anatomical deformity of the proximal femur. Our data suggests CAS technology should not be used to expand the range of utilisation of resurfacing surgery, but rather to improve the surgical outcome in those with suitable anatomy

Aims: To compare the results of resurfacing hip arthroplasty with conventional total hip replacement and to find out any differences in complication rates, discharge patterns and the resulting financial implications. Trial Design: Retrospective analysis comparing resurfacing hip arthroplasties to conventional total hip replacements in patients who were 65 years old or younger at the time of operation. Criteria for comparison were blood loss, post operative complications (including the need for blood transfusion), revision of arthroplasty and the length of hospital stay. Materials and Methods: All patients who had resurfacing arthroplasty in our hospital were included in the study (77 patients), and a similar group who had total hip replacements in the same time period were randomly selected for comparison. Case notes, computer records as well as X-rays were used to identify postoperative complications, especially DVT’s ,PE’s, neuro-vascular injuries, infection, fractured neck of femur and the need for revision of an arthroplasty. A detailed analysis of all revision arthroplasties including the causes, failure pattern of implant and the type of revision hip arthroplasty used and its cost implication was made. We also compared the pre and post-operative haemoglobin and units of blood transfused, if any. A comparison was also made of discharge pattern of these two groups of patients. A student t-test was performed to observe any difference in these two group. Results:. Resurface hip arthroplasty Group: Average age 52.1 years; pre-operative Hb 14.22gm/dl; postoperative Hb.10.95gm/dl; average blood loss 3.28 gm/dl; Total hips revised 12; Average length of stay 8.53 days. Total hip arthroplasty Group: Average age 58.8 years; pre-operative Hb 13.97gm/dl; post-operative Hb 10.65m/dl; average blood loss 3.5 gm/dl; Total hips revised 0; Average length of stay 8.9 days. Conclusions: 1.There were no appreciable differences between these two group as far as the usual complications, blood loss and length of stay are concerned. 2. There was appreciable difference in revision rate, which has significant cost implication for health authority and patients

Introduction: The Resurfacing Hip has been increasingly popular for younger patients. Femoral neck fractures are still the main complication. The problems associated with cement such as thermal necrosis, cement debris and lack of long-term biological fixation, combined with the general use of cementless fixation in young patients invite the question whether a cementless component can be used for resurfacing hip replacement. Given that the cement may reinforce the femoral head preventing collapse, an additional question regarding the effect of bone density in cemented and cementless fixation can be asked. The hypotheses of the study are that:. High bone density will increase the yield point and stiffness of the femoral head and therefore improve the implant fixation. Cement fixation will increase the yield point and stiffness of the femoral head, especially for the lower density bone compared with cementless fixation. Materials and Methods: Thirty-six femoral head specimens were obtained from consented patients receiving routine hip arthroplasty. The heads were stored frozen at −20oC until use. pQCT was used to analyse trabecular bone density within each head. Specimens were ranked according to bone density and were assigned to high and low bone density groups. Cemented and cementless fixations were then alternatively assigned to individual heads in each group. Thus the 4 groups included in the study were: High density cemented, high density cementless, low density cemented, and low density cementless. Implantation of Birmingham resurfacing hips was carried out according to recommended surgical procedures. For cementing groups, surgical simplex P bone cement was used. Each sample was potted in a cylindrical polyethylene block for testing. A compressive load up to 5 or 10 KN using a Hounsfield Universal Testing Machine were applied on each sample at a rate of 1 mm min-1. Load versus displacement graphs were plotted for all tests. Yield point and stiffness were measured for each sample. Results:. For yield point, there is no significant difference between cemented or cementless resurfacing (4169 ± 1420 N vs. 3789 ± 1461 N; P = 0.434). However, the high density heads provide a significantly higher yield point than low density heads (4749 ± 1145 N vs. 3208 ± 1287 N; P = 0.01). The addition of cement significantly contributes to femoral head stiffness compared to cementless resurfacing (5174 ± 1730 N/mm vs. 3678 ± 1630 N/mm; P = 0.012). Discussion: Bone density plays an important role in resurfacing hip arthroplasty. Higher bone density will reduce the incidence of fractures comparing with lower density. Therefore, resurfacing THR for the older patients and those with sub-optimal bone density should be used with caution. Consequently, it is suggested that a bone density scan should be routinely applied for those patients who are considered for resurfacing hip replacement. There is no difference between the cemented and cementless fixation in reducing femoral head failure, though cement will increase the stiffness of the bone. The study suggests that cementless resurfacing hip could be an alternative design with its clinical advantages of long-term osseointegration if implant is coated with bio-active materials

Background. Hip arthroscopy is well established as a diagnostic and therapeutic tool in the native hip joint. However, its application in the symptomatic post-hip arthroplasty patient is still being explored. Aims and Methods. We have described the use of hip arthroscopy in symptomatic patients following total hip replacement, resurfacing hip arthroplasty and partial resurfacing hip arthroplasty in 24 patients (study group), and compared it with arthroscopy of the native hip of 24 patients. Results. The diagnostic yield of hip arthroscopy in symptomatic post-arthroplasty patients was 95.8% (23 / 24) and a therapeutic arthroscopic intervention resulted in relief of symptoms in 41.6% (10 / 24) of the patients. It led to revision hip replacement in a further 29.1% (7 / 24). In contrast, hip arthroscopy of the native hip (control group) had a 100% diagnostic yield and an arthroscopic therapeutic intervention was carried out in all the patients resulting in symptomatic relief in 87.5% (21 / 24). The mean operative time in the study group (59.7 mins, SD 21.1) was less than the control group (71 mins, SD 17.1, p < 0.05) but the arthroscopic approach was more difficult. Conclusion. The authors suggest the use of hip arthroscopy in well-investigated symptomatic post-arthroplasty patients with an elusive diagnosis (Fig. 1: Arthroscopic image showing a THR in situ (Furlong, JRI, London, UK) with a ceramic femoral head (yellow arrow), ceramic acetabular liner (white arrow), florid metallosis (red arrow) and corrosion on the femoral neck (green arrow) because of impingement against the margin of the acetabular component.) and also describe the technical modifications necessary with various types of hip arthroplasty

Analysis of the different phases of the gait cycle has been shown to demonstrate differences in pathological osteoarthritic gait. These differences can be quantified and their improvement following total hip arthroplasty has been shown, allowing use of gait analysis as a tool in evaluating function after total hip replacements. The purpose of this study was to determine the degree of improvement in gait attained after resurfacing hip arthroplasty. Ten patients with monoarthritic hips were evaluated using gait analysis preoperatively and 1 year postoperatively. The results indicate that there is a significant improvement in the patients gait during the first postoperative year following resurfacing arthroplasty. There is a 30% increase in the Harris Hip score, 100% increase in the velocity of walking. 51% increase in stride length, 30% improvement in the ground reaction force and 33% improvement in cadence at 1 year. These improvements in gait mirror those shown previously following Total hip arthroplasty and show that following resurfacing procedures gait parameters are comparable to able-bodied controls. We have concluded that resurfacing hip arthroplasty can greatly improve the gait characteristics of patients with unilateral degenerative hip arthritis

Aim: The purpose of the study was to compare the position of the femoral guide wire for during hip resurfacing, computer navigation and an alignment device. Materials and Methods: 26 cadaver specimens divided in 3 randomly selected groups and 25 patients were used to evaluate the position of the femoral guide wire in resurfacing hip arthroplasty. In two groups of cadavers the Computer Navigation was used to register and template the position of the implant. The position of the guide wire was compared to the one achieved using the alignment device. In the third group of cadaver specimens only the alignment device was used to implant the guide wire. Version was determined from the transversely cut sections of the cadaver specimens. Pre operative and post operative radiographs were used for analysis. In the patient group after registration and templating the guide wire was passed using the alignment device. Results: There was no notching of the superior femoral neck in either of the groups. The mean and standard deviation of the anatomic neck-shaft angles was 124.91? ? 14.25?. The wire-shaft angle in the Navigation group was 131.46? ? 5.27? and in the alignment device group 134.08? ? 3.80?. In the navigation group the wire was in 0.85? ? 2.15? of retroversion as compared to 1.38? ? 4.19? of anteversion in Jig group. The position of the wires at the narrowest cross section of the femoral neck is shown in figure. The wire shaft angle as per navigation was 134.44(±5.55) as compared to 134.74 (±5.11). Conclusion: The alignment device consistently positioned the wire more valgus and anteverted than Computer aided navigation. In all cases, the wire position was well within acceptable limits. Computer aided navigation does not seem to offer distinct advantages in resurfacing hip replacements

Aims: To determine the pathological changes in the femur following resurfacing hip arthroplasty and identify possible causes of early failure. Methods: Bone samples from 8 femoral heads at several levels were examined histologically following removal of cemented femoral head surface replacement following aseptic early failure: 4 neck fractures (no history of fall), 3 persistent severe pain and 1 cup loosening. Intra-operatively no obvious macroscopic causes of failure (including notching the neck) were noted. In all patients, the initial diagnosis had been osteoarthritis. None had known risk factors for osteonecrosis. Results: In the patients who had recent fracture, the bony changes were suggestive of relatively longstanding osteonecrosis with degenerative, necrotic and þbrotic changes in the bone marrow and loss of osteocyte nuclei in the trabeculae. There was appositional new bone formation at the surface of the necrotic bone trabeculae. The changes were consistent with osteonecrosis of more than 2 weeks duration and probably preceded the fracture in all cases. In the patients who underwent revision for non-fracture, some osteonecrosis was seen, but this was a lot less than when a fracture had occurred. Conclusion: Osteonecrosis of the femoral head is seen following resurfacing hip arthroplasty and may be a predisposing factor in patients who subsequently fracture

Background: Resurfacing hip replacement is becoming increasingly used surgical option for young active patients with disabling hip arthritis.However there is a paucity of published literature describing complications and their avoidance. Objective The objective of this study was to analyse 6 cases of postoperative subcapital fracture following hip resurfacing with a cohort of 54 cases that did not have a fracture and to identify factors associated with fractures risk. Materials and Methods Between January 1999 and October 2003, 60 hips in 54 patients were treated with metal on metal resurfacing hip replacement (MMT Birmingham, UK).6 of these sustained a fracture just below the femoral component.The notes and radiographs were reviewed.Demographics data was recorded along with height, weight,smoking habits and medication usage including NSAIDS and antiepileptic use.The radiographs were studied for notching of the neck,offset difference as compared to normal and the stem shaft angle. The results were statistically analysed to determine any significant associations. Results 57 hips in 51 patients were analysed for comparison. The mean age of the patients was 50 yrs (Range 34–67).In the fracture cases there were three men and three women with a mean age of 48 yrs.Five of six ( 83%) in the fracture cases had notching of the femoral necks compared to 9 (17%) out of 51 of the non fractured patients. The offset was significantly greater in the fractured group(52 ± 7mm) compared to the non fractured group (49 ± 7 mm).The increase in offset appeared to occur as a result of incomplete seating of tight fitting cemented femoral component. The head size appeared smaller in the fractured group but the difference was insignificant. There was no significant trauma in any of the cases. None of the patients who underwent resurfacing for AVN and cyst had a fracture. There were no other significant correlations. Conclusions Increased offset and notching are factors which predispose to fractures following resurfacing hip replacements. AVN and cysts were not associated with fractures in our series. We have changed the cementing technique using smaller volumes of freshly mixed simplex cement and now encourage protected weight bearing if intraoperative notching is noted or if osteoporosis is identified pre or peri operatively. We have had no fractures in the last 18 months

Introduction and Aims: The use of resurfacing hip replacements has increased dramatically in recent years. The aim of this study was to compare the early results of this treatment with conventional cemented, cementless and hybrid primary total hip replacement in Australia. Method: The data used for this report included all conventional primary total hip and resurfacing procedures, as well as any subsequent revisions of those procedures which had been undertaken and reported to the Australian Orthopaedic Association National Joint Replacement Registry (AOA NJRR) before 31 December 2002. Analysis included the determination of demographics, components used and method of fixation. Early revision rates and reasons for failure were also assessed. The AOA NJRR commenced data collection in September 1999 and has had national coverage since 2002, therefore any results reported at this stage are early outcomes. Results: Almost 33,000 primary total hip replacements were recorded, of these 2130 were resurfacing procedures (6.5%). This proportion of resurfacing was consistent across states with the exceptions of Victoria (11%) and Tasmania (0.6%). Cementless hip replacement was the most common form of primary total hip replacement (41%) with hybrid (34%) and cemented (18.2 %) less common. There was marked state variation in the proportion of cemented and cementless fixation with NSW having a low proportion of cement fixation (4.5%). Early revision rates for cemented conventional primary total hip replacement are significantly less compared to cementless and hybrid hips (cemented v cementless) hazard ratio (adjusted for age and sex) 2.13; 95% CI (1.49, 3.05) p< 0.0001) (cemented v hybrid) hazard ratio (adjusted for age and sex) 1.94; 95% CI (1.37, 2.77) p=0.0002). There was no difference between cementless and hybrid hips. The most common reason for early revision was dislocation and the risk of this was related to head size with larger sizes showing a reduced risk. Although revisions per 100 observed component years were higher for resurfacing hip replacements than for conventional hips (1.73 v 1.18), this difference was not statistically significant. The principal reason for early failure of resurfacing hips was fracture. Conclusion: The AOA NJRR has identified prosthesis specific differences in early outcomes and failure mechanisms following primary total hip replacement. Continued monitoring of existing and new prostheses will provide surgeons with independent quality information to assist in the selection of the most appropriate prostheses for particular clinical situations

Background. Since the development of modern total hip replacement (THR) more than 50 years ago, thousands of devices have been developed in attempt to improve patient outcomes and prolong implant survival. Modern THR devices are often broadly classified according to their method of fixation; cemented, uncemented or hybrid (typically an uncemented acetabular component with a cemented stem). Due to early failures of THR in young active patients, the concept of hip resurfacing was revisited in the 1990's and numerous prostheses were developed to serve this patient cohort, some with excellent clinical results. Experience with metal-on-metal (MoM) bearing related issues particularly involving the ASR (DePuy Synthes, Warsaw, Indiana) precipitated a fall in the use of hip resurfacing (HR) prostheses in Australia from a peak of 30.2% in 2004 to 4.3% in 2015. The effects of poorly performing prostheses and what is now recognised as suboptimal patient selection are reflected in the AOANJRR cumulative percent revision (CPR) data which demonstrates 13.2% revision at 15 years for all resurfacing hip replacements combined; with 11 different types of hip resurfacing prostheses recorded for patients less than 55 years of age and a primary diagnosis of OA. When this data is restricted to only those prostheses currently used in Australia (BHR; Smith and Nephew, Birmingham, UK & ADEPT; MatOrtho Ltd, Surrey, UK) there is a CPR of 9.5% at 15 years for all patients. Despite these CPR results, recognition is emerging of the important distinction between MoM THR and resurfacing. Furthermore, in light of current consensus for patient selection and the surgical indications for resurfacing, a gender analysis demonstrates a CPR for females of 14.5% at 10 years compared to 3.7% for males. Similar difference for head size >50mm with 6% CPR at 10 years compared to 17.6% for head size <50mm (HR=2.15; 1.76, 2.63; p<0.001). Leading to renewed interest in resurfacing particularly in the young, active male. In addition to registry based CPR data, several studies have concluded that a true difference in mortality rates between HR and other forms of THR exists independent of age, sex or other confounding factors. We hypothesised that a difference in adjusted mortality rates between HR and other forms of THR may also be present in the Australian population. We undertook an ad hoc data report request to the AOANJRR. The data set provided was deidentified for patient, surgeon and institution and included all HR and conventional THR procedures performed for the diagnosis of primary osteoarthritis recorded in the Registry since inception in 1999. We requested mortality and yearly cumulative percent survival (CPS) of patients for primary HR and THR with sub-group analysis by the mode of fixation. There were 12,910 hip resurfacings (79% male) compared to 234,484 conventional THR (46.8% male) over the study period. When adjusted for age and gender over the 15 years of available data, there was a statistically significant difference in cumulative percent survival (CPS) between conventional THR and hip resurfacing (HR 1.66 (1.52, 1.82; p<0.001)) and between cemented THR and hip resurfacing (HR 1.96 (1.78, 2.43; p<0.001)); between uncemented THR and hip resurfacing (HR 1.58 (1.45, 1.73; p<0.001)); and between hybrid THR and hip resurfacing (HR 1.82 (1.66, 1.99; p<0.001)). When adjusted for age, gender and ASA over the 3 years data available, there was no statistically significant difference in CPS between hip resurfacing and any individual fixation type of THR. Discussion. The results demonstrate a statistically significant adjusted survival advantage for hip resurfacing compared to conventional THR and between fixation methods for THR. These findings are consistent with previous studies. While a difference in adjusted mortality rate appears to exist, we are yet to definitively determine the complex interplay of causative factors that may contribute to it

The metal on metal implants was introduced without the proper stepwise introduction. The ASR resurfacing hip arthroplasty (RHA) withdrawn due to high clinical failure rates and the large diameter head THA (LDH-THA) are also widely abandoned. Early (2 year) radiostereometry studies does not support early instability as cause of failure but more likely metal wear products. A possible advantage may be maintenance of bone mineral density (BMD). We present 5 year prospective follow up from a randomized series, aiming to report changes from baseline and to investigate links between implant micromotion, Cr & Co ions and BMD. Patients eligible for an artificial hip were randomized to RHA, Biomet LDH-THA or standard Biometric THA. 19, 17 and 15 patients completed 5 year follow-up. All followed with BMD of the femur, acetabulum and for RHA the collum. RHA and THA with whole blood Co and Co. LDH-THA only at 5 year. RHA had marker based RSA of both components, cup only for LDH-THA. Translations were compiled to total translation (TT= √(x. 2. +y. 2. +z. 2. )). Data were collected at baseline, 8 weeks, 6 months, 1, 2 and 5 years. Statistical tests: ANCOVA for TT movement, Spearman's correlation for BMD, Cr, Co and BMI to TT at 5 years. RSA: The 5 year median (25%to75%) RHA cup translations were X=-0.00(−0.49 to 0.19) Y=0.15(−0.03 to 0.20), z=0.24(−0.42 to 0.37) and TT 0.58 (0.16 to 1.82) mm. For the LDH-THA X=−0.33(−0.90 to 0.20) Y=0.28(0.02 to 0.54), z=0.43(−1.12 to −0.19) and TT 1.06 (0.97 to 1.72) mm. The TT was statistically different (p<0.05) for the two cups. The RHA femoral component moved X=0.37(0.21 to 0.56) Y=0.02(−0.07 to 0.11), z=-0.01(−0.07 to 0.26) and TT 0.48 (0.29 to 0.60) mm at 5 years. There was no TT movement from year 2. The mean (SD) acetabular BMD was diminished to 93(90–97)% for RHA and 97(93–99.9)% for THA, but LDH-THA maintained 99(95–103)%. Overall femoral BMD was unchanged at 5 years for all interventions, but both stemmed implants lost 17% at the calcar. Median (25%to75%) whole-blood Cr peaked in the LDH-THA group with 1.7 (0.9 to 3.1) followed by RHA 1.2 (0.8 to 5.0) and THA with 0.5 (0.4 to 0.7)ppb. For Co the highest levels were found in RHA with 1.6(0.8 to 4.7) followed by LDH-THA 1.2 (0.7–1.7) and THA 0.2 (0.2 to 0.6) ppb. The only correlations above +/−0.3 for TT were the RHA femoral component with a correlation of 0.47 to BMI, 0.30 to Co and Cr. The ASR cup conversely had a negative correlation of −0.60 to BMI and again, the LDH-THA cup had a negative correlation of −0.37 to Cr. In contrast to registered revision rates, we found significantly larger movement for the Biomet cup than the ASR cup. The metal ion levels were similar. The LDH-THA cup maintained the acetabular BMD best at 5 years, but the difference was small, we are limited by small numbers and the correlations between TT and the covariates showed no clear pattern

Introduction:. Significant proximal femoral remodeling occurs after total hip arthroplasty (THA), with regions of bone loss, and regions of hypertrophy. This study compared three implants for changes in femoral bone mineral density over 2 years following primary uncemented hip arthroplasty with a conventional stem (THA), a novel femoral neck-sparing short hip stem (NS-THA), and resurfacing hip arthroplasty (RHA). Methods:. Seventy-one patients participated in this non-randomized, prospective study. All patients had a diagnosis of osteoarthritis and underwent primary uncemented hip arthroplasty. Dual Energy XRay Absorptomitry (DXA) scans were performed at preoperative, 3–7 days post-op, 6 weeks, 6 months, one, and two years post-op. Using custom 2 cm zones, 19 zones were observed for percent changes in bone mineral density (BMD). Radiographs and Harris Hip scores were obtained at each visit. Results:. Age, gender, and BMI were found to be statistically different with fewer females and lower age in the RHA group, and a lower age in the NS-THA group. In all three groups, regions that were located proximally were shown to be the most susceptible to bone loss. Combined 2 cm zones 1C/7C, 2A/6A, and 2B/6B showed statistical significance (p < 0.05). Bone loss in the proximal regions was 8–10% lower with the femoral neck-sparing short stem, and least in the RHA group, causing little to no BMD loss in proximal regions. Radiographic outcomes and clinical results including Harris Hip scores were equal between the groups. Conclusion:. Consistent with our hypothesis, it was found that hip arthroplasty with a conventional stem resulted in the highest proximal femoral bone loss, and resurfacing arthroplasty was associated with the least bone loss. The femoral neck-sparing short stem ameliorated the bone loss seen with traditional hip arthroplasty, and approximated the bone preservation seen with hip resurfacing. The short stem neck-sparing device may provide some of the benefits of hip resurfacing, but could potentially have wider indications for use

Background. Correct positioning of the femoral component in resurfacing hip arthroplasty (RHA) is an important factor in successful long-term outcomes. The purpose of computer-assisted navigation (CAS) in resurfacing is to insert the femoral neck guide wire with greater accuracy and to help size the femoral component, thus reducing the risk of notching at the head and neck junction. Several recent studies reported satisfactory precision and accuracy of CAS. However, there is little evidence that CAS is useful in the presence of anatomical deformities of the proximal femur, which is frequently observed in young patients with secondary degenerative joint disease. Aim. The purpose of this in vitro study was to determine the accuracy of an image-free RHA navigation system in the presence of angular deformity of the neck, pistol grip deformity of the head and neck junction and slipped upper femoral epiphysis deformity. Methods. An artificial phantom leg was used. Implant-shaft angles for the guide wire of the femoral component reamer were calculated, in frontal and lateral planes, with the computer navigation system and an electronic caliper combined with micro-CT. Results. With both normal anatomy and angular deformity we found close agreement between the CAS system and our measurement system. There was a consistent disagreement on both planes for the pistol grip deformity. In the presence of the slipped upper femoral epiphysis deformity, close agreement was found only on the frontal plane but calculation of the femoral head size was inaccurate. Conclusion. This is the first study designed to assess the accuracy of a femoral navigation system for RHA in the presence of anatomical deformity of the proximal femoral head and neck segment. Our data suggests CAS technology should not be used to expand the range of utilisation of resurfacing surgery to these cases but rather to improve the surgical outcome in those with suitable anatomy

Background. Hip replacement surgery is an effective treatment, however quantitative outcome does not necessarily delineate the true picture. It is important to triangulate data methods in order to ascertain important contextual factors that may influence patient perception. Aims. The aim of the current study was to explore the patient perception on resurfacing hip arthroplasty (RHA) and mini-hip arthroplasty (MHA) in a unique cohort where each patient has received a resurfacing on one side and a mini-hip on the contralateral side using both quantitative and qualitative measures (Fig. 1). Materials and methods. We identified patients in our Practice database that had undergone RHA on one side and MHA in the opposite hip. All prostheses were implanted by two experienced surgeons using a posterior approach and followed a standard anaesthetic protocol, post-operative care and rehabilitation guidelines. The patients received Cormet 2000 hip resurfacing and MiniHip (Corin®, Ciencester, UK) implants. Data were collected pre-operatively and post-operatively at weeks 6, 12, 26 52 and annually thereafter. The data included demographic details, mHHS (modified Harris Hip Score), patient satisfaction and a qualitative semi-structured interview. Data analysis was done using both quantitative (descriptive statistics, student's t-test) and qualitative (constant comparative method of grounded theory). Results. There were 24 hips in 12 patients with mean age of 63.6 years (range 42,81) and a mean follow-up of 5.3 years (SD 4.2). The mean mHHS in pre-operative and one-year post-operative period for RHA was 50.9 (SD 22.9, range 9,71) and 82.6 (SD 11.2, range 67,91) respectively with a mean improvement of 32.9. The mean mHHS in pre-operative and one-year post-operative period for MHA was 47.83 (SD 14.6, range 20,62) and 83.2 (SD 27.3 range 53,94) respectively with mean improvement of 35.3. There was no significant difference in mHHS in the two groups (p=0.26). However, the qualitative analysis showed that a patient's perception of improvement did not always reflect the validated score improvement such as in mHHS. In 8/24 of arthroplasty cases the mHHS indicated a high return to functionality, however, interview highlighted perception of a reduction in certain aspects such as range of movement and ability to perform at a high-level such as competitive windsurfing (2/24), skiing (6/24) or martial arts (2/24). The results, therefore, suggest that the quantitative data is not sensitive enough to deduce return to function in a specialised subset of patients. The interviews indicate a marginal preference for resurfacing due to improved stability. However, the differential to the satisfaction with the mini hip was not sufficient for the potential metal ion problem to be ignored and therefore mini hip was shown to offer a reasonable bone-conserving alternative. Conclusions. Results indicate the need for more than just a quantitative score to demonstrate satisfaction and that RHA generally offers better results although when the metal ion problem is taken into account the MHA can offer sufficient function and satisfaction as an alternative

Conservative hip arthroplasty with resurfacing of the acetabulum and the femoral head is an attractive concept particularly in young and active patients. The principal advantages are less femoral bone destruction and resection, avoidance of stress shielding in the proximal femoral shaft; however this technique don’t permit a same preservation of acetabular bone stock and a mini invasive surgical approach. From January 2003 the Authors have performed 5 metal-on-metal Birmingham hip resurfacings in patient under the age of 58 with avascular necrosis of the femoral head (without a wide necrosis) or primary osteoarthritis. In all cases was performed a posterior approach slightly more extended to permit the release of the gluteus maximus tendon; the rehabilitation program involve immediate full weight bearing one day postoperatively. Data were collected intraoperatively and postoperatively in a prospective way. The early clinical and radiological results are very satisfactory: resurfacing hip arthroplasty appears to be a good alternative for the treatment of young patients, permitting a preservation of femoral bone stock and early functional recovery. In our opinion the key factors for a good result is a meticulous technique and a good bone quality

The exact alignment of the femoral component is crucial for the success of hip resurfacing arthroplasty. This prospective study was performed to find whether the imageless computer-assisted navigation surgery can improve the accuracy during hip resurfacing arthroplasty by comparing the alignment of the femoral component implanted with navigation system and conventional-mechanical guided system. Forty patients were randomly allocated into 2 groups for resurfacing hip arthroplasty using Birmingham hip resurfacing system. In the conventional group, femoral component positioning was assisted by mechanical alignment guides. In the navigation group, it was assisted by an imageless computer-assisted surgical system of Vectorvision. ®. (BrainLAB, Germany). We measured the difference between the preoperative plan of femoral component’s position and postoperative results on radiographs in the 2 groups. In the conventional group, a median difference of the stem alignment was 5.4° (range, 0.2°–10.9°) and a median difference of the stem anteversion was 2.6° (range, 0°–6.5°). In the navigated group, a median difference of the stem alignment was 2.3° (range, 0.2°–4.9°) and a median difference of the stem anteversion was 1° (range, 0°–3.6°). These differences between the 2 groups were statistically significant (P< 0.05). In resurfacing arthroplasty with a hip navigation, the procedure showed a good performance and reliability. It is achieved with greater precision with a navigation system than a mechanical alignment system

Resurfacing hip arthroplasty is a successful option for the treatment of the young and active patient with hip arthritis. However, it is complicated by femoral neck fracture and avascular necrosis, which result from devascularisation during surgery. Devascularisation maybe caused by thermal necrosis. Thermal necrosis of bone has been shown to occur in temperatures of 47°C and above. We investigated the temperatures generated during femoral head preparation to see if the temperatures reached were great enough to induce osteonecrosis. Method: Eight patients with osteoarthritis underwent standard resurfacing hip arthroplasty through the posterior approach. From the first over-drilling of the femoral heads until the prosthesis was cemented in place the temperatures generated at the bone surface were recorded using an infra-red thermal imaging camera. Images were captured every 4 seconds as the operation was performed with no interference to the surgeon. Results: The maximum temperatures generated occurred during sleeve reaming at 88.4°C. Seven patients had a temperature recorded greater than 47°C. Removing the femoral caput with an oscillating saw had the highest mean temperature 62.2°C, followed by sleeve reaming (mean 48.7°C). Female patients had the lowest temperature rises and patients receiving the larger femoral prosthesis the greatest temperatures at the bone surface. Conclusions: Heat generated during femoral head preparation exceeded 47°C in all but one case. Osteonecrosis secondary to thermal insult is likely to occur during femoral head preparation. Strategies need to be devised to decrease the temperatures generated during femoral head preparation

Comparisons of blood metal ion levels of cobalt and chromium (CoCr) between metal-on-metal total and resurfacing hip arthroplasties are limited. High levels of CoCr may result in long-term adverse biological effects. We compare metal ions levels between total and resurfacing implants. 70 patients (28 males and 42 females) had a total hip arthroplasty using the Birmingham (Smith & Nephew) modular femoral component and a variety of stems, articulating with the Birmingham resurfacing component. The average age was 65.5 (±6.8) years and an average follow-up of 6.0 (±2.2) years. 170 patients (145 male and 25 female had a Birmingham resurfacing arthroplasty with an average age of 54.7 (±9.9) years and an average follow-up of 5.9 (±3.0) years. CoCr levels were measured. Bivariate correlations and independent samples t-tests were applied to determine similarities and differences within and between groups. Average ion levels in total arthroplasty patients were: Co 114.17 (±94.01) nmol/L (range 2–414); and Cr 75.12 (±68.45) nmol/L (range 10–312). Average levels in hip resurfacing arthroplasty were: Co 55.98 (±79.5) nmol/L (range 7–505); and Cr 70.77 (±87.41) nmol/L (range 5–751). Both total and resurfacing groups showed significant correlations (p<0.01) between Co and Cr levels. A significant difference was observed between the total and resurfacing group Co levels (p<0.0001). No significant difference was shown between group Cr levels (p>0.672). The average total hip replacement CoCr levels were higher than the hip resurfacing levels. While the overall activity level may be higher in the resurfacing group, possibly the incidence of stop/start frequency may be higher in the total hip replacement group. Hip resurfacing arthroplasty average CoCr levels are lower than those of total hip replacement patients. Associations between Co and Cr metal ion levels are shown within each group. Co levels differ significantly between groups where Cr does not. Long-term follow-up of CoCr levels are required