Cannulated hip screws are frequently used in the management of hip fractures. There have been concerns over the failure rate of the technique and the outcomes of those that subsequently require conversion to total hip replacement (THR). This study utilised a database of over 600 cannulated hip screw (CHS) fixations performed over a 14-year period and followed up for a minimum of one year (1-14). We identified 57 cases where a conversion to THR took place (40 females, 17 males, mean age: 71.2 years). Patient demographics, original mechanism of injury, fracture classification, reason for fixation failure, time until arthroplasty, implant type and post-arthroplasty complications were recorded. Clinical outcomes were measured using the Oxford Hip Score. The failure rate of cannulated screw treatment was 9.4% and the mean time from initial fixation to arthroplasty was 15.4 (16.5) months. Thirty six fractures were initially undisplaced and 21 were displaced. As one might expect the displaced cases tended to be younger but this didn't reach statistical significance [66.5(14.3) vs 72.7(13.1), p=0.1]. The commonest causes of failure were non-union (25 cases, 44%) and avascular necrosis (17 cases, 30%). Complications after THR consisted of one leg length discrepancy and one peri-prosthetic fracture. The mean Oxford score pre-arthroplasty was 12.2 (8.4), improving to 38.4 (11.1) at one-year. Although the pre op Oxford scores tended to be lower in patients with undisplaced fractures and higher ASA scores, the improvement was the same whatever the pre-op situation. The one-year Oxford score and the improvement in score are comparable to those seen in the literature for THR in general. In conclusion, CHS has a high success rate and where salvage arthroplasty is required it can provide good clinical outcomes with low complication rates

Pelvic bone defect in patients with severe congenital dysplasia of the hip (CDH) lead to abnormalities in lumbar spine and lower limb alignment that can determine total hip arthroplasty (THA) patients' outcome. These variables may be different in uni- or bilateral CDH. We compared the clinical outcome and the spinopelvic and lower limb radiological changes over time in patients undergoing THA due to uni- or bilateral CHD at a minimum follow-up of five years. Sixty-four patients (77 hips) undergoing THA due to severe CDH between 2006 and 2015 were analyzed: Group 1 consisted of 51 patients with unilateral CDH, and group 2, 113 patients (26 hips) with bilateral CDH. There were 32 females in group 1 and 18 in group 2 (p=0.6). The mean age was 41.6 years in group 1 and 53.6 in group 2 (p<0.001). We compared the hip, spine and knee clinical outcomes. The radiological analysis included the postoperative hip reconstruction, and the evolution of the coronal and sagittal spinopelvic parameters assessing the pelvic obliquity (PO) and the sacro-femoro-pubic (SFP) angles, and the knee mechanical axis evaluating the tibio-femoral angle (TFA). At latest follow-up, the mean Harris Hip Score was 88.6 in group 1 and 90.7 in group 2 (p=0.025). Postoperative leg length discrepancy of more than 5 mm was more frequent in group 1 (p=0.028). Postoperative lumbar back pain was reported in 23.4% of the cases and knee pain in 20.8%, however, there were no differences between groups. One supracondylar femoral osteotomy and one total knee arthroplasty were required. The radiological reconstruction of the hip was similar in both groups. The PO angle improved more in group 1 (p=0.01) from the preoperative to 6-weeks postoperative and was constant at 5 years. The SFP angle improved in both groups but there were no differences between groups (p=0.5). 30 patients in group 1 showed a TFA less than 10º and 17 in group 2 (p=0.7). Although the clinical outcome was better in terms of hip function in patients with bilateral CDH than those with unilateral CDH, the improvement in low back and knee pain was similar. Patients with unilateral dysplasia showed a better correction of the PO after THA. All spinopelvic and knee alignment parameters were corrected and maintained over time in most cases five years after THA

Neck of femur fractures are a common presentation and certain patients can be managed with a total hip replacement. To receive a total hip replacement the pelvic X-rays should be templated as per AO guidelines and a common way this is performed is by including a calibration marker on the X-ray. The aim of this study is to assess and improve upon the use of the calibration marker. Details of patients admitted with a neck of femur fracture from January 1st 2018 until December 31st 2018 were gathered and used to review each initial X-ray and determine if a calibration marker was included. 376 patients were admitted with a neck of femur fracture over the one year period. 36% of patients did not have a calibration marker on their initial pelvic X-ray and 11% did not have a chest X ray. 215 patients had an intracapsular fracture and 39 went on to have a total hip replacement. 12 patients were lacking a calibration marker on their original X ray and required a repeat X ray. After a poster was placed in the radiographer booth acting as a visual aid, the use of a calibration marker improved from 62% to 70%. Calibration markers are useful tools which can aid the pre-operative planning for hip replacement surgeries shortening operative time, increase precision and reduce prosthetic loosening, lowers the risk of peri-prosthetic fractures, reduce leg length discrepancy and ensure the required implants are available. If a marker is not included on the initial X-rays, and a patient has a neck of femur fracture which requires a joint replacement, they may have to have additional X-rays performed as was the case for 12 patients in this study. This process leads to possible delays in surgery, additional radiation and increased healthcare costs

Exeter Trauma Stem (ETS) is one of the most common implants used for treating displaced intracapsular hip fractures in the UK. We previously performed a radiographic audit of these implants which showed good placement was difficult. This was in particular relation to leg length discrepancy (LLD). This study reviewed the clinical outcomes of these patients, in particular looking at the relation of leg length discrepancy to outcome. We performed a clinical review of patients at 3 months and 1 year post ETS for hip fracture. Oxford hip score (OHS), Trendelenberg test, Visual Analogue Score (VAS) and walking aids required were recorded. Leg length discrepancy was determined radiographically on initial post op X-ray. This was recorded as Even (+/− 5mm), 6-10mm Long and >10mm long. Seventy-two patients were reviewed at 3 months and 21 at 1 year. Mean VAS was 1.6. At 3 months 66% were Trendelenberg positive. Of those Trendelenberg positive at 3 months only 42% remained positive at 1 year. Mean OHS at 3months and 1 year was 30.8 and 32.1 respectively. On radiographic review 38 implants were Even, 24 were 6-10mm Long and 10 implants were >10mm Long. There was no correlation between leg length discrepancy and either VAS or Trendelenberg test. 45 patients ambulated independently pre-op. Of these only 8 ambulated independently post-op, 18 used a stick and 11 a Zimmer frame. There was no correlation between post operative leg length discrepancy and either Visual Analogue Score, OHS or Trendelenberg test. Mean pain score was very low. There was however almost 10% of patients with a VAS greater than 6. 80% of patients dropped one ambulatory level post-op, this is consistent with previous studies. The ETS provides good pain relief with a low complication rate in the vast majority of patients

In the congenital hip dysplasia, patients treated with total hip replacement (THR) often report persistent disability and pain, with unsatisfactory function and quality of life. A major challenge is to restore the center of rotation of the hip and a satisfactory abduction function [1]. The position of the acetabular cup during THR might be crucial, as it affects abduction moment and motor function. Recently, several software systems have been developed for surgical planning of endoprostheses. Previously developed software called HipOp [2], which is routinely used in clinics, allows surgeons to properly position the prosthetic components into the 3D space of CT data. However, this software did not allow to simulate the articular range of motion and the condition of the abductor muscles. Our aim is to present HipOpCT, an advanced version of the software that includes 3D musculoskeletal planning, through the application to hip dysplasia patients to add knowledge in the diagnosis and treatment of such patients who need THR. 40 hip dysplasia patients received pre-operative CT scanning of pelvis and thighs and had their THR surgery planned using HipOpCT. The base planning includes import of CT data, positioning of prosthetic components interactively through multimodal display, as well as geometrical measurements of the implant and the host bone. The advanced planning additionally includes evaluation of femoro-acetabular impingement and calculation of leg lengths, abductor muscle lengths and lever arms through the automatic creation of a musculoskeletal model. The musculoskeletal parameters in all patients were calculated during the surgical planning, and the data were processed to evaluate pre- and post-operative differences in leg length discrepancy, length and lever arm of the abductor muscles, and how these parameters correlated. The surgical planning led to an increase in the operated leg length of 7.6 ± 5.7 mm. The variation in abductors lever arm was −0.9% ± 4.8% and significantly correlated with the variation in the operated leg length (r = −0.49), pre-operative leg length discrepancy (r = 0.32) and variation in abductors length (r = −0.32). The variation in abductors length was 6.6% ± 5.5%, and significantly correlated with the variation in the operated leg length (r = 0.92), post-operative leg length discrepancy (r = 0.37), pre-operative abductors length (r = −0.37) and variation in abductors lever arm (r = −0.32). The increase in the operated leg length was strongly correlated to the increase in abductor muscle length. Conversely, abductor lever arms slightly decreased on average, and were inversely correlated to leg length variation and abductors lengths. This interactive technology for surgical planning represent a powerful tool for orthopaedic surgeons to consider the best muscle reconstruction, and for rehabilitation specialists to achieve the best functional recovery based on biomechanical outcomes. In a parallel study, we are investigating how these advanced planning is reflected onto the function, pain and biomechanical outcome after a rehabilitation protocol is completed

Revision total hip arthroplasty (THA) presents with increasing challenges, potentially compromising the integrity of a revision. The objective of this study was to assess radiologic outcomes of patients who underwent revision THA with a modular tapered stem (Reclaim, DePuy Synthes). This study retrospectively examined all revision Reclaim THAs between 2012 and 2016. Radiologic assessment compared x-rays at two time points: immediately after surgery and the most recent x-ray available. Leg length discrepancy, subsidence and line-to-line fit was assessed. Significant subsidence was considered ≥10mm. Adequate line-to-line fit was considered ≥30mm of bicortical contact. Descriptive statistics included clinical factors (i.e. age, Paprosky classification). P values <0.05 were considered significant. A total of 81 femoral revisions were completed. There were 42 females and 38 males with a mean age of 71 years (range, 46–89). Of these, 6 were revised (dislocation, fracture or infection), and 7 were lost to follow up. Average follow up time was 18 months (range, 1–46 months). Femoral revisions were classified as Paprosky 3a or 3b. Mean stem subsidence was 4.15mm (range, 0–25.6mm). Subsidence of the femoral stem was <10mm in 88% of patients. A total of 62% of patients had both subsidence <10mm and ≥30mm of bicortical contact. In patients with <10mm subsidence, 70% had ≥30mm of bicortical contact. There was a positive trend between cortical contact and stem stability (OR 2.3). The Reclaim modular femoral system has demonstrated radiographic stability. Inadequate initial fit is a potential determinant of subsidence

Background. Children suffering from primary bone cancer necessitating resection of growth plates, may suffer progressive leg length discrepancy, which can be attenuated with extendable prostheses. A serious complication is catastrophic implant failure. Over time, bone will remodel, altering the stress pattern in the implant. By using finite element analysis we can model different bone remodeling conditions to ascertain the effect that this will have on stress distribution and magnitude. A finite element analysis was performed. Simplified computer generated models were designed of a cemented femoral Stanmore growing massive endoprosthesis. Three scenarios were designed, modelled on post-operative radiographs. Scenario 1 had a gap between the end of the femur and the implant collar, scenario 2 had no gap, but with no bone attachment into the collar, and scenario 3 had growth of the bone over the length of the collar with attachment. Physiological loading conditions were applied. The resultant stress in the implant for each scenario was measured, and compared to the strength of the material. Peak stresses were recorded at the stem-collar junction. The maximum stress recorded in the implant in scenario 1 was 3104.2Mpa, compared to 1054.4Mpa in scenario 2, and 321.2Mpa in scenario 3. Conclusions. Both accurate reduction and bone growth with attachment to the stem of a massive endoprosthesis will greatly reduce the resultant stress in the implant under loading conditions. The load is redistributed throughout the length of the bone. This may help to prevent catastrophic failure in the implant under loading conditions. Further investigations of patient findings are needed to ensure the model findings are verified. Level of Evidence. IIb (Theoretical)

Background. Plate fixation is one of several options available to surgeons for the management of pediatric femur fractures. Recent literature reports distal femoral valgus can be a complication following lateral plate fixation of femur fractures. We report on a case of extreme distal femoral valgus deformity and a lateral dislocation of the patella four years after having plate fixation of a left distal femoral fracture. Method. A single case was anonymised and retrospectively reviewed through examination of clinical and radiographic data. Results. A 15 year old male presented with 35 degree femoral valgus deformity, one inch leg length discrepancy, painful retained hardware and a lateral dislocation of the patella four years after undergoing lateral plate fixation of a left distal femur fracture. The fracture site healed after plate insertion, but later the patient reported worsening in alignment of lower extremity and complained of pain in the limb. Antero-posterior and lateral radiographs of the femur revealed 35 degrees of left distal femoral valgus. The previous femoral plate migrated proximally and was encased in bone. Due to plate migration, screws that were originally in the distal femoral metaphysis were protruding through the femoral shaft into soft tissues of the medial thigh. Successful treatment involved removal of prominent distal screws and use of a Taylor Spatial external fixator frame to correct the deformity. Lateral soft tissue release was performed to allow patellar relocation. At 12 weeks follow up leg alignment was restored, pain resolved and the patient was mobilising. Conclusion. Femoral valgus is a possible complication of lateral plate fixation in up to 30% of pediatric distal femur fractures. With this patient's combination of deformities as an example, we suggest early hardware removal after fracture union, preventing deformities developing. If plate removal is not chosen, then continued close monitoring of the patient is necessary until skeletal maturity. Level of Evidence. Type 4 (case report)

In patients with developmental dysplasia of the hip (DDH) chronic joint dislocation induces remodeling of the soft tissue with contractures, muscle atrophy, especially of the hip abductors muscles, leading to severe motor dysfunction, pain and disability (1). The aim pf the present work is to explore if a correct positioning of the prosthetic implants through 3D skeletal modeling surgical planning technologies and an adequate customized rehabilitation can be beneficial for patients with DDH in improving functional performance. The project included two branches: a methodology branch of software development for the muscular efficiency calculation, which was inserted in the Hip-Op surgical planning system (2), developed at IOR to allow surgical planning for patients with complex hip joint impairment; and a clinical branch which involved the use of the developed software as part of a clinical multicentric randomized trial. 50 patients with DDH were randomized in two groups: a simple surgical planning group and an advanced surgical planning with muscular study group. The latter followed a customized rehabilitation program for the strenghtening of hip abductor muscles. All patients were assessed before surgery (T0) and at 3 (T1) and 6 months (T2) postoperatively using clinical outcome (WOMAC, HHS, ROM, MMT, SF12, 10mt WT) and instrumental measures (Dynamometric MT). Pre- and post-operative musculoskeletal parameters obtained by the software (i.e., leg length discrepancy, hip abductor muscle lengths and lever arms) using Hip-Op during the surgical planning were considered. One Way ANOVA for ROM measurement showed a significant improvement at T2 in patients included in experimental group, as well as WOMAC, HHS and SF12 score. The Dynamometric MT score showed significant differences between at T2 (p<0.009). Spearman's rank correlation coefficients showed a significant correlation between both pre- and post-operative abductors lever arm (mm) and hip abductor muscle strength at T2 (ρ = −0.55 pre-op and ρ = −0.51 post-op, p p<0.012 and p<0.02 respectively) and between the operated pre-postoperative leg length variation (mm) and the hip abductor muscle strength (ρ = −0.55, p p<0.013). Results so far obtained showed an improvement of functional outcomes in patients undergoing hip replacement surgery who followed therapeutic diagnostic pathway sincluding a preoperative planning including the assessment of the abductiors lever arm and a dedicated rehabilitation program for the strenghtening of abductios. Particularly interesting is the inverse relationship between the strength of the hip abductor muscles and the variation of the postoperative abductor lever arm

Shortness of an extremity due to different causes is an issue that may adversely affect human life functional and psychologically. In this study, in the light of previous studies, it is aimed to develop a new expandable intramedullary system, providing lengthening in order to remove previous problems and complications and to annihilate leg length discrepancies at present and future without second surgical intervention as far as possibble by lenghtening the intramedullary nail. To this end, a new electromechanically activated intramedullary nail has been designed and generated. The intramedullary nail was designed to perform extremity lengthening electro-mechanically. The 3D design of the system is performed with computer software and the rapid and metal prototype of the system has been produced. The intramedullary nail system is comprised of three main units; Mechanical transmission unit, Electronic unit, Lengthening unit. The nail system is designed to function both mechanically and electronically complying with the requirement. This also provides an advantage that if any one (mechanic or electronic) fails, the lengthening process can continue with the other. Compression tests are applied in order to evaluate the strength of the system. The deformation values of the parts are recorded and stress values of each parts were calculated. The new system needs only 300N loading for mechanical lengthening. When 800N is considered as average human weight, the implant must withstand minumum 2400N load. Considering the safety conditions, we applied 4000N load on the new system. At 4000N, the whole system shows only 1.465 mm deformation which is less than the gap between the two bone parts. Also, when the system is implanted inside the bone, the loads are distributed proportionally between the bone and the implant. So, except for extraordinary conditions, the newly developed system is highly rigid and safe. In each applied method, lots of complications whether general or method-specific are seen. When the methods like Albizzia, ISKD and FITBONE avaliable and widely used today are examined separately, complications specific to these methods can be clearly observed [1–12]. Bliskunov Nail, Albizzia Nail and ISKD [13–18] have mechanical working principles and in these systems, lengthening process is obtained by rotational movement of the extremity. This rotational movement causes complications like pain, dislocation and uncontrolled lengthening [11,13,16,19–21]. In our newly developed system, only axial stimulation is needed for the activation of the mechanism. This is one of the advantages of our system. Both the mechanical unit and the electronical units are designed to be extended 0.1 mm at each activation. This means that the optimal amount of distraction (1mm/day) can be achieved in a controlled way. In other systems, the distraction amount can not be fully controlled and complications seen on other systems [1, 6, 8–10], like distruption of callus due to the excessive distraction and nonunion of the bone can be encountered. The success of the system at practice will be examined with in-vivo animal experiments and according to the results, it will be ready for use on human by performing necessary restorations

Summary Statement. The implantation of scaffold-free CTE from suspension culture into growth-plate defects resulted in a significant reduction in growth arrest of the rabbit tibia. Introduction. In childhood and adolescence, the growth plate injury can cause partial premature arrest of growth plate, which can make problems such as leg length discrepancy and angular deformity. Bone bridge resection and variable implantation materials such as fat, bone wax, silastic and craniopalst has been investigated. However, those procedures may show limitations including the control of bone growth and long term safety of implant materials in vivo. As an alternative, homogeneous or heterogeneous cartilage cells and stem cell transplants have been tried. In this method, scaffold for cell transplantation is needed. But, so far the most suitable scaffold has not been established. Recently, some authors generated a cartilage tissue equivalent (CTE) using a suspension culture with biophysical properties similar to native hyaline cartilage. Therefore we are able to transplant the CTE without scaffold to the physeal defect. The purpose of this study was to investigated the effects of a transplantation of a vitro-generated scaffold-free tissue-engineered cartilage tissue equivalent (CTE) using a suspension chondrocyte culture in a rabbit growth arrest model. Material and Method. Cartilage tissue equivalent culture. The CTE was generated by the suspension culture of chondrocytes (2 × 10. 7. /well/1 mL) which was isolated from articular cartilage of 5 weeks New Zealand white rabbit on a 24-well plate (2.4 cm. 2. /well) treated with poly HEMA (nunc, Roskide, Denmark) for up to 8 and 16 weeks. (2)Partial growth arrest animal model. An experimental model for growth arrest was created by excising the growth plate at the proximal medial side of tibia with the 4 mm in diameter and 4 mm in depth from 6-week-old New Zealand white rabbits. Two experimental groups were set to evaluate CTE implantation; group I, no implantation as controls; group II, implantation of CTE. (3) Evaluation of effect of the transplantation of CTE. Serial plain radiographs were performed at one week. The medial proximal tibial angle (MPTA) was measured for assessing the degree of angular deformity. Histologic examination using HE stain, Alcian bule and immunohistochemistry was done at 4 and 8 weeks after surgery. Results. Radiographic results: In group I, all damaged growth plates were arrested and angular deformities appeared 4 weeks later. In groups II, angular deformities were much less than in the control group. Histologic result: In group I, bone bridge formation was shown at the damaged growth plate at 4 weeks after surgery. In group II, regeneration of growth plates was recognised at 4 and 8 week after surgery. However, the thickness of regenerated growth plate at 8 weeks specimen was thinner than that of 4 weeks specimen. Discussion and Conclusion. The implantation of scaffold-free CTE from suspension culture into growth-plate defects resulted in a significant reduction in growth arrest of the rabbit tibia

Introduction. Even in localized collapse due to osteonecrosis of the femoral head, a femoral head can be preserved by rotational osteotomy. In addition to anterior rotation, originally described by Sugioka, much more correction can be obtained by posterior rotation. But, transtrochanteric rotational osteotomy needs rather extensive soft tissue release, such as complete capsulotomy and resection of short external rotators and psoas tendons. Many patients tend to complain about the leg length discrepancy and limp due to varus change. We found soft tissue resection and limb shortening could be minimized by doing the osteotomy at the femur neck rather than the trochanteric area following the technique of surgical dislocation. It needs careful dissection of the posterior retinacular artery to preserve circulation to the femoral head. Methods. We have performed 17 cases (14 cases were in men and 3 cases were in women), and average patient age was 45 years old. Osteotomy was applied to cases with collapse or large necrotic region that seemed to be fail by core decompression. All cases showed collapse except one (ARCO 2-B) and 6 cases were ARCO 3-A, 5 cases were ARCO 3-B, 4 cases were ARCO 3-C and one case was ARCO stage 4. Seven cases were rotated anteriorly, and ten cases were rotated posteriorly. Amount of rotation was 63 to 170 degrees in posterior rotation (mean 100.8 degrees) and mean 48 degrees in anterior rotation. The size of the necrotic area was 301 degrees according to the Koo method (combined necrotic angle in mid-coronal and mid-saggital MRI scan). Results. Harris hip scores were improved from 62 to 88 points and VAS was from 8.4 to 2.6 in 13 cases. Conversion to THA was done in 4 cases (23.5%) as pain was persisting and there was one more failed case which was lost to follow-up. Another 2 cases showed insufficient circulation in bone SPECT, but no symptoms until recently. Problems with fixatives were in 4 cases and one case had heterotopic ossification without symptom. Conclusion. In conclusion, the outcome of the operation could be identified much earlier than other procedures. 12 cases (58.8%) showed satisfactory results and 2 cases were in observation due to insufficient circulation, and 5 cases (29.4%) failed. The operative technique will be revised and we are expecting better results

The renewed interest in the clinically proven low wear of the metal-on-metal bearing combined with the capacity of inserting a thin walled cementless acetabular component has fostered the reintroduction of hip resurfacing. As in other forms of conservative hip surgery, i.e. pelvic osteotomies and impingement surgery, patient selection will help minimize complications and the need for early reoperation. Patient Selection and Hip Resurfacing. Although hip resurfacing was initially plagued with high failure rates, the introduction of metal on metal bearings as well as hybrid fixation has shown excellent survivorships of 97 to 99% at 4 to 5 years follow-up. However, it is important to critically look at the initial published results. In all of these series there was some form of patient selection. For example, in the Daniel and associates publications, only patients with osteoarthritis with an age less than 55 were included with 79% of patients being male. Treacy and associates stated that: “the operation was offered to men under the age of 65 years and women under the age of 60 years, with normal bone stock judged by plain radiographs and an expectation that they would return to an active lifestyle, including some sports”. However in the materials and methods, although the mean age is 52 years, the range is from 17 to 76 years including some patients with rheumatoid arthritis as well as osteonecrosis. Obviously, some form of patient selection is needed; but how one integrates them is where the Surface Arthroplasty Risk Index (SARI) is useful. With a maximum score of 6, points are assigned accordingly: femoral head cyst >1cm: 2 points; patient weight <82kg: 2 points; previous hip surgery: 1 point; UCLA Activity level >6: 1 point. A SARI score >3 represented a 4 fold increase risk in early failure or adverse radiological changes and with a survivorship of 89% at four years. The SARI index also proved to be relevant in assessing the outcome of the all cemented McMinn resurfacing implant (Corin¯, Circentester, England) at a mean follow-up of 8.7 years. Hips which had failed or with evidence of radiographic failure on the femoral side had a significantly higher SARI score than the remaining hips, 3.9 versus 1.9. Finally, one must consider the underlying diagnosis when evaluating a patient for hip resurfacing. In cases of dysplasia, acetabular deficiencies combined with the inability of inserting screws through the acetabular component may make initial implant stability unpredictable. This deformity in combination with a significant leg length discrepancy or valgus femoral neck could compromise the functional results of surface arthroplasty, and in those situations a stem type total hip replacement may provide a superior functional outcome. In respect to other diagnoses (osteonecrosis, inflammatory arthritis), initial analyses have not demonstrated any particular diagnostic group at greater risk of earlier failure. The only reservation we have is in patients with compromised renal function since metal ions generated from the metal-on-metal bearing are excreted through the urine and the lack of clearance of these ions may lead to excessive levels in the blood. Surgical Technique. Because resurfacing has not been within the training curriculum of orthopaedic surgeons for the last 2 decades, there will most likely be a learning curve in the integration of this implant within clinical practice. This data was confirmed for hip resurfacing when looking at the Canadian Academic Experience where in the first 50 cases of five arthroplasty surgeons only a 3.2% failure rate was noted of which 1.6% were due to neck fracture. Femoral neck fracture can occur because of significant varus positioning as well as osteonecrosis of the femoral head due to either disruption of the blood supply or over cement penetration. Finally, abnormal wear patterns leading to severe soft tissue reactions are being increasingly recognized and are related to either impingement or vertically placed acetabular components. Although impingement has long been recognized after total hip arthroplasty to limit range of motion and in extreme cases to hip instability, the risk after hip resurfacing may be greater since the femoral head-neck unit is preserved. Beaulé and associates have reported that 56% of hips treated by hip resurfacing have an abnormal offset ratio pre-operatively, with the two main diagnostic groups presenting deficient head-neck offset being osteonecrosis and osteoarthritis both of which have been associated with femoroacetabular impingement in the pre arthritic state. Conclusion. Although patients with a high activity level are likely to put their hip arthroplasties at risk for earlier failure, limiting a patient's activity because of fear of revision with a stem type hip arthroplasty has been shown to negatively impact the quality of life at long term follow-up. Thus hip resurfacing arthroplasty plays a significant role in the treatment of hip arthritis by permitting a return to full activities or what the patient perceives as his/her full capacities to do so, permitting them to enjoy a better quality of life without fearing a major hip revision