Aims. Surface replacement arthroplasty (SRA), compared with traditional total hip arthroplasty (THA), is more expensive and carries unique concern related to metal ions production and hypersensitivity. Additionally, SRA is a more demanding procedure with a decreased margin for error compared with THA. To justify its use, SRA must demonstrate comparable component survival and some clinical advantages. We therefore performed a systematic literature review to investigate the differences in complication rates, patient-reported outcomes, stress shielding, and hip biomechanics between SRA and THA. Materials and Methods. A systematic review of the literature was completed using MEDLINE and EMBASE search engines. Inclusion criteria were level I to level III articles that reported clinical outcomes following primary SRA compared with THA. An initial search yielded 2503 potential articles for inclusion. Exclusion criteria included review articles, level IV or level V evidence, less than one year’s follow-up, and previously reported data. In total, 27 articles with 4182 patients were available to analyze. Results. Fracture and infection rates were similar between SRA and THA, while dislocation rates were lower in SRA compared with THA. SRA demonstrated equivalent patient-reported outcome scores with greater activity scores and a return to high-level activities compared with THA. SRA more reliably restored native hip joint biomechanics and decreased stress shielding of the proximal femur compared with THA. Conclusion. In young active men with osteoarthritis, there is evidence that SRA offers some potential advantages over THA, including: improved return to high level activities and sport, restoration of native hip biomechanics, and decreased proximal femoral stress shielding. Continued long-term follow up is required to assess ultimate survivorship of SRA

We describe the results of Copeland surface replacement shoulder arthroplasty using the mark III prosthesis in patients over 80 years of age. End-stage arthritis of the shoulder is a source of significant pain and debilitating functional loss in the elderly. An arthroplasty offers good relief of pain and may allow the patient to maintain independence. The risk-benefit ratio of shoulder replacement may be felt to be too high in an elderly age group, but there is no published evidence to support this theory. We have assessed whether the procedure was as reliable and safe as previously seen in a younger cohort of patients. Between 1993 and 2003, 213 Copeland surface replacement arthroplasty procedures were performed in our unit, of which 29 (13.6%) were undertaken in patients over the age of 80. This group of patients was followed up for a mean of 4.5 years (2.1 to 9.3). Their mean age was 84.3 years (81 to 93), the mean operating time was 40 minutes (30 to 45) and the mean in-patient stay was five days (2 to 21). There were no peri-operative deaths or significant complications. The mean Constant score adjusted for age and gender, improved from 15.1% to 77%. Copeland surface replacement shoulder arthroplasty may be performed with minimal morbidity and rapid rehabilitation in the elderly

Surface hip replacement (SHR) is generally used in younger, active patients as an alternative conventional total hip replacement in part because of the ability to preserve femoral bone. This major benefit of surface replacement will only hold true if revision procedures of SHRs are found to provide good clinical results. A retrospective review of SHR revisions between 2007 and 2012 was presented, and the type of revision and aetiologies were recorded. There were 55 SHR revisions, of which 27 were in women. At a mean follow-up of 2.3 years (0.72 to 6.4), the mean post-operative Harris hip score (HHS) was 94.8 (66 to 100). Overall 23 were revised for mechanical reasons, nine for impingement, 13 for metallosis, nine for unexplained pain and one for sepsis. Of the type of revision surgery performed, 14 were femoral-only revisions; four were acetabular-only revisions, and 37 were complete revisions. We did not find that clinical scores were significantly different between gender or different types of revisions. However, the mean post-operative HHS was significantly lower in patients revised for unexplained pain compared with patients revised for mechanical reasons (86.9 (66 to 100) versus 99 (96 to 100); p = 0.029). There were two re-revisions for infection in the entire cohort. Based on the overall clinical results, we believe that revision of SHR can have good or excellent results and warrants a continued use of the procedure in selected patients. Close monitoring of these patients facilitates early intervention, as we believe that tissue damage may be related to the duration of an ongoing problem. There should be a low threshold to revise a surface replacement if there is component malposition, rising metal ion levels, or evidence of soft-tissue abnormalities. Cite this article: Bone Joint J 2013;95-B, Supple A:88–91

Fractures of the proximal humerus can lead to malalignment of the humeral head, necrosis and post-traumatic osteoarthritis. In such cases surface replacement might be a promising option. A total of 28 shoulders with glenohumeral arthritis subsequent to a fracture underwent surface replacement arthroplasty of the humeral head in patients with a mean age of 60 years (35 to 83). On the basis of the inclination of the impacted head, post-traumatic arthritis was divided into three types: type 1, an impacted fracture of the head in an anatomical position (seven cases); type 2, a valgus impacted fracture (13 cases); type 3, a varus impacted fracture (eight cases). The outcome was measured by means of the Constant score. According to the Boileau classification of the sequelae of fractures of the proximal humerus, all 28 patients had a final result of intra-capsular category 1. The mean Constant score for the 28 shoulders increased from 23.2 points (2 to 45) pre-operatively to 55.1 points (20 to 89) at a mean of 31 months (24 to 66) post-operatively. Valgus impacted fractures had significantly better results (p < 0.039). Surface replacement arthroplasty can provide good results for patients with post-traumatic osteoarthritis of the shoulder. Their use avoids post-operative complications of the humeral shaft, such as peri-prosthetic fractures. Further surgery can be undertaken more easily as the bone stock is preserved

There has been a renewed interest in surface replacement arthroplasty over the last decade, with the hope and expectation that this procedure would provide an advantage over conventional total hip arthroplasty, especially in the young, active patient. More specifically, the promises of surface replacement arthroplasty have been: 1) preservation of bone stock so that future revisions would be easier, 2) potential to be minimally invasive in their approach, 3) better functional outcomes because of the stability associated with a larger femoral head with potential associated proprioceptive advantages, and 4) improved survivorship. Unfortunately, these promises have not been realised. Surface replacement arthroplasty does maintain more initial bone stock on the femur, but also tends to remove more bone initially on the acetabular side. Long term, it is the loss of acetabular bone stock that is more problematic from a reconstructive perspective. Further, the “simple” revision afforded in surface replacement arthroplasty has led to reports of inferior clinical outcomes, especially with respect to subjective complaints of pain. Surface replacement arthroplasty is more invasive than conventional total hip arthroplasty as the femoral head is maintained and the window to the acetabulum is subsequently partially blocked. This is exacerbated by the fact that many of these patients are young active males. There is no compelling evidence that surface replacement arthroplasty offers improved functional outcomes over conventional total hip arthroplasty, particularly when considering gait and proprioception. Some studies have in fact shown inferior outcomes. The concept of the larger femoral head in surface replacement arthroplasty providing increased range of motion and subsequent better function is flawed as it is the head-to-neck ratio that appears to be a more important determinant of outcome in this sense. Total hip arthroplasty generally has a more favorable ratio. Surface replacement arthroplasty has inferior survivorship to conventional total hip arthroplasty, even when accounting for the younger age of this patient cohort. This finding is consistent across multiple national joint replacement registries. The outcomes and survivorship are particularly poor in females, with many authors now advocating that the procedure be reserved for males. Surface replacement arthroplasty has introduced several new problems and mechanisms of failures, most concerning of which is the formation of pseudotumors in some patients. It is unclear as to who is at risk for this significant complication, and the ability to diagnose and treat this disorder is difficult and still in evolution. Likely associated is the significant elevation of metal ions in the serum and urine of some surface replacement arthroplasty patients. Neck fractures and loss of bone stock around the femoral implant have also been noted as problematic for these devices. Some of these problems have led to specific surface replacement arthroplasty systems being recalled. Finally, surface replacement arthroplasties are premium products with associated increased costs, which, frankly, are not justified

Surface replacement of the hip was established in the 1970's as a bone preserving alternative to total hip replacement. However, problems with femoral neck fracture, osteolysis, and component loosening led to early failures and an abandonment of the procedure. The modern generation of hip resurfacing, however, has improved upon past results with new implant designs and materials. Better surgical guides and a short femoral stem allows for more accurate placement of the implants. A metal-on-metal articulation creates a larger diameter bearing and avoids polyethylene wear debris. Also paramount in the recent successes of surface replacement are refinements in surgical techniques, leading to more accurate component positioning, avoidance of neck notching, and an appreciation of the femoral head blood supply. The mid-term results of these newer hip resurfacing devices, coupled with appropriate patient selection and good surgical technique, have been encouraging. Although more recently surface replacement has come under fire because of the metal-on-metal articulation, the Australian National Joint Registry finds that a certain group of patients has greater survivorship with resurfacing than with total hip replacement. Therefore, the presenter feels that surface replacement arthroplasty is still a viable option in this subgroup of patients. Additionally, the benefits of surface replacement include the preservation of bone, a lower dislocation rate, and potentially a higher activity level

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

Introduction: Shoulder surface replacement arthroplasty has been established for several decades as a mean to restore comfort and function of the shoulder for many afflictions that derange the normal anatomy. The surface replacement may offer some advantages over the stemmed prostheses. Purpose: The purpose of the study was to evaluate the clinical and radiological results of Copeland cementless surface replacement arthroplasty (CSRA) applied in patients with bony defects of the humeral head. Patients and Methods: The study was conducted on 18 patients (2 patients with chronic posterior dislocation, 8 patients with AVN, 8 patients with posttraumatic head necrosis) with bony head defects that were operated on between 1999 and 2006. The patients were followed up clinically and radiologically for a mean of 24.8 months (range, 10–78 months). There were 8 female and 10 male shoulders. The mean age was 55.3 years (range, 27–71). The clinical assessment was performed with the Constant score. Results: The constant score significantly improved from a mean of 14.83 points preoperatively to 64.34 points postoperatively. The average pain score increased from 0.3 points to 9.8 points. The average ROM score increased from 8.21 points to 23.21 points. The humeral offset increased from 22.3 mm to 28.8 mm. Conclusion: The shoulder surface replacement arthroplasty shows good mid-term results in patients with bony defects

Cementless surface replacement arthroplasty of the shoulder is designed to replace the damaged joint surfaces and restore normal anatomy with minimal resection of bone. We have used the Copeland shoulder arthroplasty for 14 years. Between 1986 and 2000, 285 surface replacement arthroplasties were implanted in our unit. The prosthesis has evolved during this time, but the principle of minimal bone resection has remained the same. Between 1990 and 1994, 103 Mark-2 prostheses were inserted into 94 patients (9 bilateral). The operations were carried out for the treatment of osteoarthritis, rheumatoid arthritis, avascular necrosis, instability arthropathy, post-traumatic arthropathy and cuff arthropathy. The mean follow-up was for 6.8 years (5 to 10). The best results were achieved in primary osteoarthritis, with Constant scores of 93.7% for total shoulder replacement and 73.5% for hemiarthroplasty. The poorest results were seen in patients with cuff arthropathy and post-traumatic arthropathy with adjusted Constant scores of 61.3% and 62.7%, respectively. Most patients (93.9%) considered their shoulder to be much better or better than before the operation. Of the 88 humeral implants available for radiological review, 61 (69.3%) showed no evidence of radiolucency, nor did 21 (35.6%) of the 59 glenoid prostheses. Three were definitely loose, and eight shoulders required revision (7.7%), two (1.9%) for primary loosening. The results of this series are comparable with those for stemmed prostheses with a similar follow-up and case mix. The cementless surface replacement arthroplasty diminishes the risk of complications involving the humeral shaft and periprosthetic fractures. Revision or arthrodesis can be undertaken easily since the bone stock has been maintained with no loss of length

Surface replacement of the hip has become established as an alternative treatment to total hip replacement in the younger, active, male patient. By the very nature of preserving the femoral head and neck, there may be failures due to femoral neck fracture and femoral component loosening. Additionally, revisions of hip resurfacing for acetabular loosening may be necessary. Other scientific papers have described problems that may arise as a result of the metal-on-metal bearing either due to excess metal production or an immunologic-mediated reaction to the metal debris. Grammatopolous et al. describe poor results of revisions of surface replacements due to massive tissue destruction at the time of revision surgery, persistent pain, and swelling. In my experience with hip resurfacing, this complication is extremely rare. In my series of 925 resurfacings with a minimum of 2 year follow up, 12 revisions (1.3%) have been performed. Of these revisions, only 3 (0.3%) were for complications related to the metal-on-metal bearing; 2 for edge-loading and excess metal production, and 1 for metal hypersensitivity. None of the revision cases have had abductor destruction, or nerve/vascular involvement. Reconstruction of the joint was carried out with standard and revision components; post-operative function of these patients has been comparable to that of a primary total hip replacement. With careful monitoring of the post-operative resurfacing patient, problems can be identified early and surface replacement conversion can be performed with excellent results

Introduction: Glenohumeral arthritis with a massive rotator cuff tear is a devastating condition that seriously compromises the comfort and function of the shoulder. Cuff tear arthropathy presents a unique surgical challenge and many arthroplasty options were used for its treatment. The purpose of this study was to evaluate the clinical and radiological results of Copeland cementless surface replacement arthroplasty (CSRA) applied in patients with cuff tear arthropathy and intact subscapularis function. Patients and Methods: The study was conducted on twenty five shoulders in twenty five patients with cuff tear arthropathy with the subscapularis tendon still intact. The patients were prospectively followed up clinically and radiologically for a mean of 26 months (range, 15–38 months). There were 16 female and 9 male shoulders. The mean age was 69.04 years (range,53–83years). The mean operative time was 38 minutes (range, 28–56minutes). The clinical assessment was performed with the Constant score. Results: The constant score significantly improved from a mean of 14.04 points preoperatively to 53.17 points postoperatively. Of the patients, 88% considered the shoulder to be much better or better as a result of the operation. Radiologically, the humeral offset, the lateral gleno-humeral offset (coracoid base to the greater tuberosity), height of center of instant rotation and the acromio-humeral distance were significantly increased. No intra-or postoperative complications encountered. Conclusion: Our early results with the use of Copeland surface replacement in selected cases with cuff tear arthropathy were encouraging. The patients showed significant clinical (pain and range of motion) and radiological improvements. Moreover, if the surface replacement were to fail for any reason, it can be revised to a reverse prosthesis type as there is no lack of bone stock

Avascular necrosis (AVN) of the humeral head is an extremely disabling condition (Gerber et al, JSES 1998. 7(6):586–90). The results of stemmed arthroplasty for this condition are good, with Hattrup and Cofield reporting 79% subjective improvement at nine years (JSES 2000;9:177–82). This study reports the outcomes of surface replacement shoulder arthroplasties for AVN over a 16 year period. Between 1986 and 2001 twenty-seven arthroplasties were performed in patients with advanced avascular necrosis of the humeral head. All patients had secondary degenerative changes. AVN was secondary to corticosteriods and trauma in most cases. The mean age of the patients was 60 years (range 35 to 86). These included 16 hemiarthroplasties and 7 total shoulder arthroplasties. All prostheses were of the Copeland Surface Replacement Arthroplasty (CSRA) type. The average follow up period was 6 years (range 1 to 13). The average preoperative Constant score was 17. This improved to 74 at follow-up. Forward flexion improved from 63 degrees preoperatively to 133 degrees at follow-up. Abduction improved from 49 degrees to 118 degrees. External rotation improved from −3 degrees to 61 degrees. Pain scores improved from 0 to 11.7, using a 15 point visual analogue scale. 81% of patients had slight and no difficulty performing their routine activities of daily living. The remaining 19% still had some difficulty with routine activities. Four of the patients performed regular overhead activity and recorded some difficulty in doing this, whereas they had great difficulty pre-operatively. There were no cases of loosening. No difference was seen in any of the results between the hemi-arthroplasty and total shoulder replacement patients. Surface replacement arthroplasty is a suitable procedure for degenerative disease secondary to AVN of the humeral head, with results similar to stemmed prostheses. It has the advantage of preserving bone stock

The Copeland Shoulder Arthroplasty is a cementless, pegged humeral head surface replacement. The design is based on the principle of minimal bone resection and has been in clinical use since 1986. The only published series to date, that of Levy and Copeland, reported results for 103 patients which were comparable to those obtained with stemmed implants. We report the outcome at our institution using the same prosthesis with a hydroxyapatite coating. 81 shoulders (74 patients) underwent resurfacing hemiarthroplasty through an anterior deltopectoral approach. Preoperative diagnoses were: osteoarthritis (39), rheumatoid arthritis (29), rotator cuff arthropathy (1), post-traumatic arthrosis (2). They were followed for an average 28 months. 10 were lost to follow-up (8 deaths). Constant scores improved from a mean preoperative figure of 15.7 to 54.0 (p< 0.01) at last follow-up. For rheumatoid arthritis and osteoarthritis the scores improved from 15.2 to 50.4 (p< 0.01) and 16.0 to 55.4 (p,< 0.01) respectively. There was a 13% complication rate with one case requiring revision for loosening to a stemmed implant. Most were cases requiring subsequent acromioplasty. In one case the glenoid rim was fractured during head dislocation. There was a low rate of perioprosthetic radiolucency (4.2%) which may relate to the hydroxyappatite coating within the shell of the prosthesis. Ipsilateral stemmed elbow replacement was performed in some cases without a double stress riser effect. Periprosthetic humeral neck fracture as managed non-operatively with uneventful union. Conclusion: The good outcome reported in Copeland’s own series has been replicated in the early to medium term at our institution. The surface replacement system is simpler, accurate and preserves bone stock

Introduction: There is an increasing interest in surface replacement arthroplasty (SRA) as an alternative to conventional THA (cTHA) in young and active patients. However, there has been considerable variability in reported outcomes. National joint registry reports have shown increased revision rates compared to cTHA. We analysed outcome measured as non-septic revision rate within two years for SRA in the NARA data base (Nordic Arthroplasty Register Association). Materials and Methods: 1638 SRA and 163802 cTHA with age up to 73 years and a non-fracture diagnosis, operated from 1995 to 2007, were compared using Cox multiple regression including age, gender, diagnosis, nation and prosthesis type with cTHA divided into cemented, uncemented, hybrid and reversed hybrid fixation. Men below 50 years of age (460 SRA and 7185 cTHA) were analysed as a subset. The SRA cohort with a mean follow-up 1,8 years was also analysed with the same method including age, gender, diagnosis, number of performed SRA per hospital and the four most commonly used prosthesis designs. In an additional analysis femoral head diameter was added, reducing the number of cases to 1552. results are presented as relative risk (RR) with 95 % confidence interval(CI). Results: SRA had a more than twofold increased revision risk compared to cTHA, RR=2,50 (1,67–3,70), which increased to 3,63 (2,42–5,44) when compared with all cemented THA. In the subpopulation of men below 50 years of age, there was no difference between SRA and any of the cTHA cathegories. Within the SRA group RR was reduced by male gender, RR=0,46 (0,25–0,86), in hospital performing > 70 SRA (RR=0,26, 0,11–0,60) and with use of BHR (Birmingham Hip Resurfacing) compared to all other designs (RR=0,27, 0,12–0,61). The size of the femoral head diameter had no significant influence on the early revision rate. Discussion and Conclusion: Surface replacement arthroplasty has an increased risk of early revision compared to conventional and cemented THA except for men below 50 years of age. There is a learning curve on the hospital level. Cases with secondary osteoarthritis were comparatively few and were mainly caused by pediatric hip disease. SRA might become an alternative for young men, but our follow up is too short to determine if this indication remains in the longer perspective

The Articular Surface Replacement (ASR) hip resurfacing arthroplasty has a failure rate of 12.0% at five years, compared with 4.3% for the Birmingham Hip Resurfacing (BHR). We analysed 66 ASR and 64 BHR explanted metal-on-metal hip replacements with the aim of understanding their mechanisms of failure. We measured the linear wear rates of the acetabular and femoral components and analysed the clinical cause of failure, pre-revision blood metal ion levels and orientation of the acetabular component. There was no significant difference in metal ion levels (chromium, p = 0.82; cobalt, p = 0.40) or head wear rate (p = 0.14) between the two groups. The ASR had a significantly increased rate of wear of the acetabular component (p = 0.03) and a significantly increased occurrence of edge loading (p < 0.005), which can be attributed to differences in design between the ASR and BHR. The effects of differences in design on the in vivo wear rates are discussed: these may provide an explanation as to why the ASR is more sensitive to suboptimal positioning than the BHR

Introduction: Rheumatoid arthritis often leads to severe destruction of the glenohumeral joint including synovitis and inflammation induced alterations of the rotator cuff. Cup arthroplasty, or surface replacement of the shoulder was introduced in the 1980s. The aim of this study was to confirm or withdraw the very promising results of the DUROM-Cup surface replacement for patients with rheumatoid arthritis. Patients an Methods: From 1997 to 2000 a cohort of 42 DUROM-Cup hemiprotheses were implanted in 35 patients. The patients were evaluated preoperatively and after 3,12 and more than 60 month postoperatively. 7 patients were lost to follow up. A total of 35 DUROM-Cups (29 patients) could be examined prospectively after an average follow up period of 73.1 (+/− 12.1) month (Average age 61.4y, female n=21, male n=68). Rotator cuff defects were classified intraoperatively. Results: Three revisions occured: One due to a too large implant, one due to glenoid erosion and one due to loosening of the implant. The constant score increased from preoperatively 20.8 points to 64.3 points at a mean follow up of 73.1 month. No differences were seen in patients with massive cuff tears. In these cases the cup was implanted in a more valgic position, so that articulation with the acromion could be achieved. The radiographic results did not show any changing of the parameters for the position of the cup. No further endo-prosthetic loosening was observed. The proximal migration increased in 66% and the glenoid depht increased in 37% of the cups. Discussion: The results of the cemented DUROM-Cup surface replacement for patients with advanced rheumatoid arthritis of the shoulder are very encouraging, especially in patients with massive tearing of the rotator cuff. The advantages of cup arthroplasty are to be found in the reduced level of invasive surgery and the simpler technique with bone saving fixation. In the event of failure of the implant good further treatment options for salvage procedures remain

Copeland Surface replacement arthroplasty provides a good outcome in cases of arthritis. However, the limitation of use of this prosthesis is severe bone loss of the humeral head. We describe the use of Copeland Surface Replacement Shoulder Arthroplasty in cases of severe humeral head destruction extending more than 50% of the humeral head. The bone deficiency was reconstructed with the autograft from the reaming and reshaping of the humeral head and a synthetic bone graft substitute (Tricalcium phosphate granules (Biosorb)) mixed with the patient’s blood. We report preliminary results in 8 cases. 3 males and 4 females (One patient bilateral). The average age was 48 years ( 22–76 years). 5 cases had Posttraumatic avascular necrosis of humeral head, two patients had locked posterior fracture dislocation with loss of more than 50% of the humeral head and one patient with severe juvenile rheumatoid arthritis. In this series the remaining bone of humeral head was less than 50% ranging between 30–50% (average 38%). The patients were followed clinically and radiographically. The average follow–up was 10.6 months (range: 5 to 15 months). All patients had substantial improvement in there shoulder function and pain. All the patients were very satisfied. Average pre-op constant score was 9.3 points (range: 9–14). At the latest follow-up the average constant score was 59 (range: 36–74). Age and sex adjusted constant score was 68.6 (range: 37– 87). Radiographically we observed good incorporation of the Bone graft substitute with no signs of loosening or any lucencies under the prosthesis. These are early and encouraging results in this group of young patients with severe destruction of the humeral head. It seems like it may provide a good bone preserving solution in these cases and extend the frontiers for the surface replacement of the shoulder

The classic Hill-Sachs lesion is a compression or impression fracture of the humeral head in occurrence with anterior glenohumeral instability. The true incidence is unknown but clearly increases with recurrent instability episodes. Recent peer-reviewed literature has highlighted the importance of addressing “significant” humeral and glenoid bone defects in the management of glenohumeral instability. Quantification of the “significance” of a Hill-Sachs lesion with regard to location, size, and depth in relation to the glenoid has helped guide indications for surgical management. Options for managing Hill-Sachs lesions include both humeral-sided techniques (soft tissue, bone, and/or prosthetic techniques) and also glenoid-sided techniques (bone transfers to increase glenoid width). The majority of significant acute or chronic Hill-Sachs lesions can be effectively managed without prosthetic replacement. Is a prosthetic surface replacement ever indicated for the management of Hill-Sachs lesions? The peer-reviewed literature is sparse with the outcomes of this treatment, and significant consideration must be given to both the age of the patient and the need for such management when other effective non-prosthetic options exist. In a patient with more than half of the humeral head involved after instability episodes (perhaps seizure or polytrauma patients), metallic surface replacement arthroplasty may be an option that could require less involved post-operative care while restoring range of motion and stability

Introduction: Surface replacement of the hip has been proposed as an alternative to total hip replacement, particularly in young active patients. The suggested benefits include preservation of bone stock for future revision surgery and avoidance of proximal femoral stress protection, which can cause bone resorption. However, following femoral head resurfacing, femoral neck fracture can occur. The aim of this study was to compare the strain pattern in intact and resurfaced femurs using validated third generation composite femurs and rosette strain gauges. Methods: Rosette strain gauges were applied to an intact and a resurfaced third generation composite femur at three sites; narrowest part of the lateral surface of the neck, narrowest part of the medial surface of the neck and medial surface at the level of lesser trochanter. The femurs were loaded with axial loads of 600N, 800N and 1000N sequentially. The tests were repeated thrice for each femur. Maximum and minimum principal strains were calculated. Further tests were carried out in which an abductor load was included in the model. Testing was done at 600N and repeated thrice for each femur. The principal strains were calculated and compared with the the principal strains without the abductor load. Results: The maximum principal strains in the resurfaced femur were approximately 50% higher in the lateral surface of the neck and about 30% higher in the lesser trochanteric region when loaded without including an abductor force. Inclusion of the abductor force decreased the strain particularly at the lateral surface of the neck by approximately 45% in the intact femur and approximately 25% in the implanted femur. Even with the inclusion of the abductor load the strain in the resurfaced femur remained more than 50% higher at the lateral surface of the neck and 20% higher in the lesser trochanteric region. Conclusion: Our study suggests that proximal femoral stress protection will not occur following surface replacement of the hip. The increased strain at the lateral surface of the neck could result in fracture, particularly if there is notching of the neck or if abductor function has been compromised, which can happen particularly with the direct lateral approach

Aims. Our first aim was to determine whether there are significant changes in the level of metal ions in the blood at mid-term follow-up, in patients with an Articular Surface Replacement (ASR) arthroplasty. Secondly, we sought to identify risk factors for any increases. Patients and Methods. The study involved 435 patients who underwent unilateral, metal-on-metal (MoM) hip resurfacing (HRA) or total hip arthroplasty (THA). These patients all had one measurement of the level of metal ions in the blood before seven years had passed post-operatively (early evaluation) and one after seven years had passed post-operatively (mid-term evaluation). Changes in ion levels were tested using a Wilcoxon signed-rank test. We identified subgroups at the highest risk of increase using a multivariable linear logistic regression model. Results. There were significant increases in the levels of metal ions for patients who underwent both MoM HRA (Chromium (Cr): 0.5 parts per billion (ppb); Cobalt (Co): 1.1 ppb) and MoM THA (Cr: 0.5 ppb; Co: 0.7 ppb). In a multivariable model considering MoM HRAs, the change in the levels of metal ions was influenced by female gender (Co: Odds Ratio (OR) 1.42; p = 0.002 and Cr: OR 1.08; p = 0.006). The change was found to be irrespective of the initial level for the MoM HRAs, whereas there was a negative relationship between the initial level and the change in the level for those with a MoM THA (Co: OR -0.43; p <  0.001 and Cr: OR -0.14; p = 0.033). Conclusion. The levels of metal ions in the blood increase significantly over the period until mid-term follow-up in patients with both a MoM HRA and those with a MoM THA. We recommend that the levels of metal ions be measured most frequently for women with a MoM HRA. While those with a MoM THA appear to stabilise at a certain level, the accuracy of this trend is not yet clear. Vigilant follow-up is still recommended. . Cite this article: Bone Joint J 2017;99-B(4 Supple B):33–40

Biologic resurfacing of the glenoid combined with surface replacement hemiarthroplasty for relatively young patients suffering from advanced glenohumeral arthritis has the advantages of both humeral head and glenoid bone preservation. The longer term results of this procedure are reported. Twenty two shoulders in 21 patients had a surface replacement hemiarthroplasty with resurfacing of the glenoid with the anterior capsule. At follow up one had died, and another was not contactable. The prosthesis was removed in one for deep infection, and the fourth patient had undergone revision to a total shoulder arthroplasty for ongoing pain. Therefore, 17 patients with 18 operated shoulders were available for clinical assessment. The average age of the patients was 54.8 years (35–78) at the time of surgery. The average length of follow-up was 4.8 years (2–10.6). The average Constant Score was 71.4 points (41–95), and the sex- and age-adjusted Constant Score was 83.9%. The mean ASES score was 74.4 points (35–100). The average arc of forward flexion was 130 degrees (100–160), and external rotation was 39 degrees (20–60). On a VAS scale of 0 to 10, the average pain score at rest was 0.5 (0–3), while pain with activity was 2.4 (0–6). Sixteen of the 17 patients (94%) had a satisfactory result, and would have the operation again. Eight of the 17 patients (47%) were able to return to their previous sporting activities. Radiographic follow-up demonstrated there were 2 mild and 2 moderate cases of superior subluxation of the humeral head. There was no subsidence or signs of loosening of any humeral prosthesis. The average glenohumeral joint space was 0.13mm (0–2). Glenoid erosion was none in one case, mild in 6 cases, moderate in 6 cases, and severe in 3 shoulders. Although the results of this procedure compare favourably with other series, the extent of glenoid erosion is concerning. A more robust tissue for interposition may give better results

Total hip arthroplasty (THA) is among the most successful interventions in all of medicine and has recently been termed “The Operation of the Century”. Charnley originally stated that “Objectives must be reasonable. Neither surgeons nor engineers will ever make an artificial hip joint that will last 30 years and at some time in this period enable the patient to play football.” and he defined an appropriate patient as generally being over 65 years of age. Hip rating scales developed during this time were consistent with this approach and only required relief of pain and return to normal activities of daily living to achieve a perfect score. Since this time, however, hip arthroplasty has been applied to high numbers of younger, more active individuals and patient expectations have increased. One recent study showed that in spite of a good hip score, only 43% of patients had all of their expectations completely fulfilled following THA. The current generation metal-metal hip surface replacement arthroplasty (SRA) has been suggested as an alternative to standard THA which may offer advantages to patients including retention of more native bone, less stress shielding, less thigh pain due to absence of a stem, less limb length discrepancy, and a higher activity level. A recent technology review by the AAOS determined that currently available literature was inadequate to verify any of these suggested potential benefits. The potential complications associated with SRA have been well documented recently. The indications are narrower, the implant is more expensive, the technique is more demanding and less forgiving, and the results are both highly product and surgeon specific. Unless a clinical advantage in the level of function of SRA over THA can be demonstrated, continued enthusiasm for this technique is hard to justify. To generate data on the level of function of younger more active arthroplasty patients, a national multicenter survey was conducted by an independent university medical interviewing center with a long track record of conducting state and federal medical surveys. All patients were under 60, high demand (pre-morbid UCLA score > 6) and had received a cementless stem with an advanced bearing surface or an SRA at one of five major total joint centers throughout the country. The detailed questionnaire quantified symptoms and function related to employment, recreation, and sexual function. Patients with SRA had a higher incidence of noises emanating from the hip than other bearing surfaces although this was transient and asymptomatic. SRA patients were much more likely to have less thigh pain than THA, less likely to limp, less likely to perceive a limb length difference, more likely to run for exercise, and more likely to run longer distances. In another study of over 400 THA and SRA patients at two major academic centers, patients completed pain drawings that revealed an equivalent incidence of groin pain between THA and SRA, but an incidence of thigh pain in THA that was three times higher than in SRA in young active patients. While some or most of the observed advantages of SRA over THA may be attributable to some degree of selection bias, the inescapable conclusion is that SRA patients are demonstrating clinical advantages that warrants continued utilization and investigation of this procedure

Total hip arthroplasty is among the most successful interventions in all of medicine and has recently been termed “The Operation of the Century”. Charnley originally stated that “Objectives must be reasonable. Neither surgeons nor engineers will ever make an artificial hip joint that will last 30 years and at some time in this period enable the patient to play football.” and he defined appropriate patient as generally being over 65 years of age. Hip rating scales developed during this time were consistent with this approach and only required relief of pain and return to normal activities of daily living to achieve a perfect score. Since this time, however, hip arthroplasty has been applied to high numbers of younger, more active individuals and patient expectations have increased. One recent study showed that in spite of a good hip score, only 43% of patients had all of their expectations completely fulfilled following THA. The current generation metal-metal hip surface replacement arthroplasty (SRA) has been suggested as an alternative to standard THA which may offer advantages to patients including retention of more native bone, less stress shielding, less thigh pain due to absence of a stem, less limb length discrepancy, and a higher activity level. A recent technology review by the AAOS determined that currently available literature was inadequate to verify any of these suggested potential benefits. The potential complications associated with SRA have been well documented recently. The indications are narrower, the implant is more expensive, the technique is more demanding and less forgiving, and the results are both highly product and surgeon specific. Unless a clinical advantage in the level of function of SRA over THA can be demonstrated, continued enthusiasm for this technique is hard to justify. To generate data on the level of function of younger more active arthroplasty patients, a national multicenter survey was conducted by an independent university medical interviewing center with a long track record of conducting state and federal medical surveys. All patients were under 60, high demand (pre-morbid UCLA score > 6) and had received a cementless stem with an advanced bearing surface or an SRA at one of five major total joint centers throughout the country. The detailed questionnaire quantified symptoms and function related to employment, recreation, and sexual function. Patients with SRA had a higher incidence of noises emanating from the hip than other bearing surfaces although this was transient and asymptomatic. SRA patients were much more likely to have less thigh pain than THA, less likely to limp, less likely to perceive a limb length difference, more likely to run for exercise, and more likely to run longer distances. In another study of over 400 THA and SRA patients at two major academic centers, patients completed pain drawings that revealed an equivalent incidence of groin pain between THA and SRA, but an incidence of thigh pain in THA that was three times higher than in SRA in young active patients. While some or most of the observed advantages of SRA over THA may be attributable to some degree of selection bias, the inescapable conclusion is that SRA patients are demonstrating clinical advantages that warrants continued utilisation and investigation of this procedure

Purpose: The presence of metal ions in the blood of patients with a metal-on-metal (MM) bearing points to the importance of understanding the long-term effects of these ions. Metal ions have the potential to induce the production of reactive oxygen species (ROS), making them prime suspects for inducing molecular damage in circulating cells. The aim of this study was to analyze the levels of oxidative stress markers in the plasma of patients with hip surface replacement. Method: Blood was collected up to 3 years after implantation from 66 patients with articular surface replacement (ASRÔ, DePuy Orthopaedics) and 54 patients with 36 mm-head MM THA. Forty (40) pre-operative patients were also assessed as control group. Total anti-oxidant levels were measured by the Oxford Biomedical total antioxidant power assay (Oxford, MI) to obtain an overview of the defense capacity of patient’s oxidative stress. Peroxide concentrations were measured by the Biomedica OxyStat assay (Medicorp, Montreal, QC) to quantify damage to lipids in the systemic circulation. Nitrototyrosine levels were quantified using the BIOXYTECH® Nitrotyrosine-EIA assay (OxisResearch™, Portland OR) to measure damage to proteins. The concentrations of metal ions were analyzed by inductively coupled plasma-mass spectroscopy. Results: Results showed that there were no statistical differences in the concentrations of total antioxidants, lipid peroxides, and protein nitrotyrosines between the control, the ASR, and the 36 mm-head groups. Furthermore, there was no correlation between the concentrations of these markers and the concentrations of both Co and Cr ions (r2 £ 0.006). Conclusion: The single most significant obstacle preventing a broader application of metal-on-metal hip arthroplasties and resurfacings continues to be the concerns regarding elevated metal ion levels in the blood and urine of patients. The present results showed that there were no changes in the levels of oxidative stress markers in patients with MM bearings compared to the control group. Given the possible latency periods related to metal ion exposure, longer follow-ups are required to conclusively determine the effects of elevated circulating ions on oxidative stress in the blood of patients with MM bearings

We present the early clinical and radiological results of Articular Surface Replacement (ASR) resurfacings in 214 hips (192 patients) with a mean follow-up of 43 months (30 to 57). The mean age of the patients was 56 years (28 to 74) and 85 hips (40%) were in 78 women. The mean Harris hip score improved from 52 (11 to 81) to 95 (27 to 100) at two years and the mean University of California, Los Angeles activity score from 3.9 (1 to 10) to 7.4 (2 to 10) in the same period. Narrowing of the neck (to a maximum of 9%) was noted in 124 of 209 hips (60%). There were 12 revisions (5.6%) involving four (1.9%) early fractures of the femoral neck and two (0.9%) episodes of collapse of the femoral head secondary to avascular necrosis. Six patients (2.8%) had failure related to metal wear debris. The overall survival for our series was 93% (95% confidence interval 80 to 98) and 89% (95% confidence interval 82 to 96) for hips with acetabular components smaller than 56 mm in diameter. The ASR implant has a lower diametrical clearance and a subhemispherical acetabular component when compared with other more frequently implanted metal-on-metal hip resurfacings. These changes may contribute to the higher failure rate than in other series, compared with other designs. Given our poor results with the small components we are no longer implanting the smaller size

Introduction: Metal-metal (MM) surface replacement arthroplasty of the hip is showing promise as an effective and enduring solution in the management of hip arthritis in the young, and is being increasingly used. The main concern is the release of metal ions into the systemic circulation and their long-term effects. There is concern that metal ions cross the placenta in pregnant women with MM bearing arthroplasties with the potential for mutagenic effects in the offspring. The hypothesis is that metal ions pass freely through the placenta and that there is no difference in the maternal and cord metal ion levels. Methods: This is a controlled cross-sectional study of women of child-bearing age with MM bearing surface replacement arthroplasties. (n= 25, mean age: 32 years, mean duration after resurfacing 60.3 months, 3 bilateral). The control group consisted of 24 subjects who do not have a metallic implant, were not taking any supplements containing cobalt or chromium salts and were registered to undergo an elective LSCS at the regional hospital. Mean age of the control group was 31.3 years. No patient in either group was known to have renal failure. Whole blood specimens were obtained from the mothers just before delivery and before infusion of any fluids, and cord blood specimens were obtained immediately after delivery. High resolution inductively couples mass spectrometry (HRICPMS) was used for metal ion analysis. Results: Cobalt and chromium were detectable in all specimens in both the study patients and controls. In the study group, mean cord metal ion levels were significantly lower than the maternal cobalt (p < 0.05) and chromium (p < 0.0001) levels thus rejecting the null hypothesis. In the control group, the mean difference between maternal and cord metal ion levels was only 5 to 7% and was statistically not significant (p > 0.5). The mean difference in cord chromium between the study and control groups is not statistically significant (p > 0.05), although cord cobalt in the study group is significantly higher (p < 0.01) than that in controls. Whilst there is a four-fold elevation of maternal cobalt in the study patients and an almost 7-fold increase in maternal chromium levels as compared to the control group, the elevation in the cord cobalt and chromium in the study group are smaller. Discussion and Conclusion: The differences between maternal and cord metal ions in the control patients indicate that normally the placenta allows an almost free passage of metal ions. This is understandable when we realize that these elements are also required by the developing foetus for its cellular and metabolic functions. The relative levels of metal ions in the maternal and cord blood in the study group patients reveal that the placenta does exert a modulatory effect on metal transfer. The mean cord levels of cobalt and chromium in these patients are only 57% and 24% of the maternal blood levels respectively. There is a continuing need for efforts to reduce metal ion release from artificial joints and also to monitor metal ion levels in patients with MM devices

Hill-Sachs and reverse Hill-Sachs lesions come in different shapes and sizes, and their effect on “glenoid track” can vary. Small Hill-Sachs lesions that do not engage can be successfully treated with a Bankart repair alone done arthroscopically or open. Moderate, engaging, Hill-Sachs lesions can be treated either with the addition of remplissage to an arthroscopic Bankart or by adding the triple blocking effect of the Bristow-Latarjet procedure. Surface replacements vary in size from the small hemi-cap type of procedure to an entire humeral head replacement (HHR). These devices can be used as opposed to allograft replacement when the risk of post-reconstruction arthritis is high with the aforementioned more conventional treatment techniques. When 45% or more of the humeral head is involved with the lesion, or Outerbridge stage III and IV changes prevail, a HHR is preferred. An oval shaped HHR is the author's preference, and the long diameter can be used to provide coverage anteriorly or posteriorly and is particularly useful in large Hill-Sachs lesions associated with epilepsy

We evaluated the concentrations of chromium and cobalt ions in blood after metal-on-metal surface replacement arthroplasty using a wrought-forged, high carbon content chromium-cobalt alloy implant in 64 patients. At one year, mean whole blood ion levels were 1.61 μg/L (0.4 to 5.5) for chromium and 0.67 μg/L (0.23 to 2.09) for cobalt. The pre-operative ion levels, component size, female gender and the inclination of the acetabular component were inversely proportional to the values of chromium and/or cobalt ions at one year postoperatively. Other factors, such as age and level of activity, did not correlate with the levels of metal ions. We found that the levels of the ions in the serum were 1.39 and 1.37 times higher for chromium and cobalt respectively than those in the whole blood. The levels of metal ions obtained may be specific to the hip resurfacing implant and reflect its manufacturing process

Metal-metal surface replacement (MoMSRA) is increasingly used in the young. Systemic metal ion release and its effects cause concern. Do metal ions cross the placenta in pregnant women with potential mutagenic effects? The hypothesis is that metal ions pass freely through the placenta and there is no difference in maternal and cord metal levels. This is a controlled cross-sectional study of women with MoMSRA. (n=25, mean age 32years, implantation 60months, 3 bilateral). The control group were 24 subjects with no metallic implant and not receiving cobalt/chromium supplements, mean age 31years. No patient was known to have renal failure. Whole blood specimens were obtained before delivery/ fluid-infusion and Cord blood specimens immediately after delivery. Cobalt and chromium were detectable in all specimens in both cohorts. In the control group, the difference between maternal and cord levels was only 5 to 7% indicating free passage. Study group cord levels were significantly lower than maternal cobalt, p<0.05 and chromium p<0.0001 thus rejecting the null hypothesis. The differences between maternal and cord metal ions in the controls indicate that normally the placenta allows an almost free passage of metal ions. The relative levels of metal ions in the maternal and cord blood in the study group reveal that the placenta exerts a modulatory effect on metal transfer

Hip resurfacing is widely recognised as a bone conserving procedure with respect to proximal femoral resection. However, it has been argued that this is not the case for the acetabulum due to the thickness of the acetabular component and the large diameter bearing surfaces. We have investigated whether the Birmingham Hip is a bone conserving procedure with respect to the acetabular bone stock. Data was obtained from 257 consecutive Midland Medical Technology (MMT) surface replacements and 458 primary hybrid total hip replacements implanted under our care. The surface replacement group comprised 185 males (185 hips) and 72 females (72 hips) with a mean age at surgery of 55 years. The hybrid primary total hip replacement group comprised 207 males (207) and 251 females (251 hips). The mean age at surgery was 65 years old. In the surface replacement group the mean uncemented acetabular size implanted was 54.88 mm (females = 51.9 mm; males = 57.8 mm). In the hybrid primary total hip replacement group the mean uncemented acetabular size of 55.04 mm (females =52.9 mm; males = 57.2 mm). Statistical analysis was undertaken to compare the uncemented acetabular sizes in the surface replacement group with the uncemented acetabular sizes implanted in the primary hybrid total hip replacement group. We report no significant difference in the size of acetabular component used for the two groups (p = 0.4629; 95% C.I. −0.28 to 0.61). The effect of gender was analysed and the mean size of uncemented acetabular component implanted in males for the surface replacement group was not significantly different (p = 0.06) to the hybrid primary total hip replacement group. However the mean size of uncemented acetabular component in females for the surface replacement group was significantly smaller (p = 0.016) compared to the primary total hip replacement group. We conclude hip resurfacing is not bone sacrificing on the acetabular bone stock and can be bone conserving for females

The aim of this study was to assess the medium-term results of the Copeland cementless surface replacement of the shoulder for rheumatoid arthritis. Between 1986 and 1998, 75 patients with rheumatoid arthritis had a cementless surface replacement. They were 58 females and 17 males with a mean age 60 years (range: 24 to 88 years). The mean follow-up was 6 years (range: 2 to 14 years). The functional outcome was assessed using the Constant score and a patient satisfaction scale. The mean Constant score was 53.4 points for total shoulder replacements (76 age/ sex adjusted) and 47.9 points for hemiarthroplasty (71 age/ sex adjusted). Forward elevation improved from 50 degrees to 104 degrees for total shoulder replacements and from 47 degrees to 101 degrees for hemiarthroplasty. Seventytwo patients (96%) considered the shoulder to be better or much better. 3 patients (4%) felt the shoulder was the same. The deltopectoral approach was used in 38 while the antero-superior (Mackenzie) approach was used in 37 shoulders. The rotator cuff was intact in 24 shoulders, thin but intact in 21 shoulders, had a full thickness tear in 26 shoulders and a massive tear in four shoulders. Sixty-eight patients were available for radiological review. Fifty-six (82.4%) humeral components showed no lucent lines. Eleven (16.2%) showed localised lucent lines < 1mm and one was loose. Of the 39 glenoid components, 19 (48.7%) showed no lucent lines, 19 (48.7%) showed lucent lines < 1mm and one was loose. No lucencies were observed in the hydroxyapatite coated implants. Two patients in the total shoulder group with massive cuff tears required revision for component loosening. One patient in the hemiarthroplasty group was revised to a total due to pain, with complete pain relief. The results of CSRA are at least comparable to stemmed prosthesis in rheumatoid arthritis. However, CSRA preserves bone stock and allows easier revision in this relatively young group of patients. It also reduces the risk of humeral shaft fractures compared to a stemmed implant, especially when an elbow replacement is needed

The Hill-Sachs lesion is a bony defect of the humeral head that occurs in association with anterior instability of the glenohumeral joint. Hill-Sachs lesions are common, with an incidence approaching nearly 100% in the setting of recurrent anterior glenohumeral instability. However, the indications for surgical management are very limited, with less than 10% of anterior instability patients considered for treatment of the Hill-Sachs lesion. Of utmost importance is addressing bone loss on the anterior-inferior glenoid, which is highly successful at preventing recurrence of instability even with humeral bone loss. In the rare situation where the Hill-Sachs lesion may continue to engage the glenoid, surgical management is indicated. Surgical strategies are variable, including debridement, arthroscopic remplissage, allograft transplantation, surface replacement, and arthroplasty. Given that the population with these defects is typically comprised of young and athletic patients, biologic solutions are most likely to be associated with decades of sustainable joint preservation, function, and stability. The first priority is maximizing the treatment of anterior instability on the glenoid side. Then, small lesions of less than 10% are ignored without consequence. Lesions involving 10–20% of the humeral head are treated with arthroscopic remplissage (defect filled with repair of capsule and infraspinatus). Lesions greater than 20% that extend beyond the glenoid tract are managed with fresh osteochondral allografts to biologically restore the humeral head. Lesions great than 40% are most commonly associated with advanced arthritis and deformity of the humeral articular surface and are therefore treated with a humeral head replacement. This treatment algorithm maximises our ability to stabilise and preserve the glenohumeral joint

It has been proposed that a major advantage of surface replacement is that it is easy to revise and that the outcome of such revisions is good. This seems logical as the femoral head can easily be removed, the acetabular component can be cut out and a primary hip replacement can be inserted. Indeed a number of studies have shown good outcome following revision, particularly for femoral neck fracture. When we initially reviewed the results of our revisions we found that the operations were straight forward and the results were good provided the reasons for revision were neck fractures, loosening, infection and causes other than soft tissue reactions. When the reason for revision was soft tissue reaction, otherwise known as pseudotumour, the outcome was unsatisfactory with poor hip scores, and high rates of complications, revisions and recurrences. These were generally a manifestation of the soft tissue damage caused by the pseudotumours. We therefor recommended that early revisions should be considered with soft tissue reaction. By undertaking revisions earlier we have found that the results have improved but there are still cases with poor outcomes

Purpose: The purpose of the study was to evaluate the clinical and radiological results of Copeland cementless surface replacement arthroplasty (CSRA) applied in patients with two main indications. Patients and Methods: The study was conducted on fifty shoulders in fifty patients between 2003 and 2005; 17 patients suffered from rotator cuff pathology. The patients were prospectively followed up clinically and radiologically for a mean of 12.7 months (range, 6–30 months). There were 30 female and 20 male shoulders. The mean age was 66.63 years (range, 21–85). The mean operative time was 44.6 minutes (range, 29–62 minutes). The clinical assessment was performed with the Constant score. Results: The constant score significantly improved from a mean of 15.52 points preoperatively to 57.02 points postoperatively. Of the patients, 96% considered the shoulder to be much better or better as a result of the operation. The Constant-Score improved in the group with degenerative arthritis from 16.32 point pre- to 62.25 postoperatively. In rotator cuff arthropathy the score improved from 14.19 to 53.06. Radiologically, the humeral offset, the lateral gleno-humeral offset (coracoid base to the greater tuberosity) as well as the acromiohumeral distance were significantly increased. No intra-or postoperative complications encountered. Conclusion: We conclude that the shoulder surface replacement arthroplasty allows good conservation of the bone stock and avoiding the complications encountered with the stemmed prostheses. In patients with rotator cuff arthropathy there are two main indications:. - patients below the age of 70, in order to avoid complications of the reverse prosthesis. - patients with still a goof active range of motion

Introduction. Studies of metal-on-metal (MoM) hip resurfacing arthroplasty (HRA) have reported high complication and failure rates due to elevated metal ion levels. These rates were shown to be especially high for the Articular Surface Replacement (ASR) HRA, possibly due to its unique design. Associations between metal ion concentrations and various biological and mechanical factors have been reported. Component positioning as measured by acetabular inclination has been shown to be of especially strong consequence in metal ion production in ASR HRA patients, but few studies have evaluated acetabular anteversion as an independent variable. The primary objective of this study was to evaluate the associations between component orientation, quantified by acetabular inclination and anteversion, and blood metal ions. Secondly, we sought to report whether conventional safe zones apply to MoM HRA implants or if these implants require their own positioning standards. Methods. We conducted a multi-center, prospective study of 512 unilateral ASR HRA patients enrolled from September 2012 to June 2015. At time of enrollment our patients were a mean of 7 (3–11.5) years from surgery. The mean age at surgery was 56 years and 24% were female. All subjects had complete demographic and surgical information and blood metal ions. In addition, each patient had valid AP pelvis and shoot-though lateral radiographs read by 5 validated readers measuring acetabular abduction and anteversion, and femoral offset. A multivariate logistic regression was used with high cobalt or chromium (greater than or equal to 7ppb) as the dependent variable. The independent variables were: female gender, UCLA activity score, age at surgery, femoral head size, time from surgery, femoral offset, acetabular abduction, and acetabular anteversion. Results. The average acetabular inclination angle was found to be 44.7° (20.6°–64.5°), and the average anteversion angle was 24° (0.2°–55.3°) (Figure 1). After controlling for the possible confounding variables, the factors contributing to elevated metal ions (≥ 7 ppb) were found to be time from surgery (OR = 1.29, p = 0.011), high abduction angle (– 55°) (OR = 4.40, p = 0.001), low anteversion angle (0°–10°) (OR = 3.82, p = 0.001), and female gender (OR = 3.45, p = 0.001). Discussion and Conclusion. We found that blood metal ion levels are affected by both acetabular inclination and anteversion (Figure 2). Furthermore, we observed that there was a high degree of variation in the positioning of these implants, and we conclude that those with high inclination and/or low anteversion angle should be most vigilantly monitored

Considerable controversy remains in the literature as to whether hemiarthroplasty or total shoulder arthroplasty (TSA) is the better treatment option for patients with shoulder arthritis. Several cohort studies have compared the outcomes of stemmed hemiarthroplasty with those of stemmed TSA and had inconsistent conclusions as to which procedure is best. However, these studies suggest that stemmed TSA provided better functional outcome. 340 CSRA cases were performed between 1987–2003, 218 Hemiarthroplasty – Humeral Surface Arthroplasty (HSA) and 122 TSA. There was very little difference in the functional outcome and pain in patients with and without a glenoid implant early, as well as, later after surgery. Mean post-operative Constant score for TSA was 85.0% (59.8 points) and for HSA patients 86.8% (62.3 points) with no statistically significant differences (t-test, p=0.4821). A highly significant difference between the overall proportions of revised cases was observed, with (21/122) 17.2% and (6/218) 2.8% of TSA and HSA cases revised, respectively (p< 0.0001). Further, HSA prostheses survive significantly longer than TSA prostheses. The difference between the survival curves was highly significant, both in the earlier post-operative period (Wilcoxon’s test, p=0.0053) as well as the later on (Log-rank test, p=0.0028). Long-term survival of total joint replacement is related to polyethylene wear debris, and therefore its use should be avoided if possible. The difference between our series and those with stemmed prostheses may be due to the fact that with surface replacement the normal anatomy for each patient can be mimicked better than with the stemmed prostheses and there is substantially less place for error as in stem positioning, head sizing or wrong version that may lead to glenoid erosion and less favourable result. Our current practice is and we suggest performing Copeland humeral surface replacement without insertion of glenoid prosthesis

Cementless surface replacement arthroplasty (CSRA) is an established treatment for glenohumeral osteoarthritis. Few studies however, evaluate its role in cuff tear arthopathy. The purpose of this study is to compare the outcomes of CSRA for both glenohumeral osteoarthritis and cuff tear arthopathy. 42 CSRA with the Mark IV Copeland prosthesis were performed for glenohumeral osteoarthritis (n=21) or cuff tear arthopathy (n=21). Patients were assessed with Oxford and Constant scores, patient satisfaction, range of motion and radiologically with plain radiographs. Mean follow-up and age was 5.2 years and 74 years in both groups. Functional outcomes were significantly higher in OA compared with CTA with OSS improving from 18 to 37.5 and 15 to 26 in both groups respectively. Forward flexion improved from 60° to 126° and 42° to 74° in both groups. Three patients in the CTA group had a deficient subscapularis tendon, two of whom dislocated anteriorly. Humeral head resurfacing arthroplasty is a viable treatment option for glenohumeral osteoarthritis. In patients with CTA, functional gains are limited. We suggest CSRA should be considered in low demand patients where pain is the primary problem. Caution should be taken in patients with a deficient subscapularis due to the high risk of dislocation

The Hill-Sachs lesion is a bony defect of the humeral head that occurs in association with anterior instability of the glenohumeral joint. Hill-Sachs lesions are common, with an incidence approaching nearly 100% in the setting of recurrent anterior glenohumeral instability. However, the indications for surgical management are very limited, with less than 10% of anterior instability patients considered for treatment of the Hill-Sachs lesion. Of utmost importance is addressing bone loss on the anterior-inferior glenoid, which is highly successful at preventing recurrence of instability even with humeral bone loss. In the rare situation where the Hill-Sachs lesion may continue to engage the glenoid, surgical management is indicated. Surgical strategies are variable, including debridement, arthroscopic remplissage, allograft transplantation, surface replacement, and arthroplasty. Given that the population with these defects is typically comprised of young and athletic patients, biologic solutions are most likely to be associated with decades of sustainable joint preservation, function, and stability. The first priority is maximising the treatment of anterior instability on the glenoid side. Then, small lesions of less than 10% are ignored without consequence. Lesions involving 10–20% of the humeral head are treated with arthroscopic remplissage (defect filled with repair of capsule and infraspinatus). Lesions greater than 20% that extend beyond the glenoid tract are managed with fresh osteochondral allografts to biologically restore the humeral head. Lesions great than 40% are most commonly associated with advanced arthritis and deformity of the humeral articular surface and are therefore treated with a humeral head replacement. This treatment algorithm maximises our ability to stabilise and preserve the glenohumeral joint

Aim: To compare the strain pattern in intact and resurfaced femurs with and without abductor force using validated third generation composite femurs and rosette strain gauges. Methods: Rosette strain gauges were applied to an intact and a resurfaced third generation composite femur at three sites; narrowest part of the lateral surface of the neck, narrowest part of the medial surface of the neck and medial surface at the level of lesser trochanter. The femurs were loaded with axial loads of 600N, 800N and 1000N sequentially. The tests were repeated thrice for each femur. Maximum and minimum principal strains were calculated. Further tests were carried out in which an abductor load was included in the model. Testing was done at 600N and repeated thrice for each femur. The principal strains were calculated and compared with the principal strains without the abductor load. Results: The maximum principal strains in the resurfaced femur were approximately 50% higher in the lateral surface of the neck and about 30% higher in the lesser trochanteric region when loaded without including an abductor force. Inclusion of the abductor force decreased the strain particularly at the lateral surface of the neck by approximately 45% in the intact femur and approximately 25% in the implanted femur. Even with the inclusion of the abductor load, the strain in the resurfaced femur remained more than 50% higher at the lateral surface of the neck and 20% higher in the lesser trochanteric region. Conclusion: Our study suggests that proximal femoral stress protection will not occur following surface replacement of the hip. The increased strain at the lateral surface of the neck could result in fracture, particularly if there is notching of the neck or if abductor function has been compromised, which can happen with the direct lateral approach

Purpose: Precise biomechanical reconstruction of the hip joint by a hip arthroplasty is essential for the success of this procedure. With the increasing use of surface replacement arthroplasty (SRA), there is a need for better understanding of the key factors that influence the anatomical and the biomechanical parameters of the resurfaced hip joint. The goal of this study was to examine the influence of SRA on the vertical and horizontal offset of the hip. Method: Twenty-one hips from 12 embalmed cadavers were resurfaced with a Birmingham Hip resurfacing. The thickness of the acetabular bone was measured pre- and post-reaming in 6 acetabular zones. Radiographs were taken before and after the procedure with a scaling marker. For statistical analysis, the paired Student’s T-test with a confidence interval of 95% and a significant p-value of p< 0.05 was used. Results: The mean acetabular bone loss was 3.8 mm, 5.9 mm, 9.3 mm, 10.6 mm, 8.5 mm and 3.6 mm in zones 1 to 6. The “polar length loss” is the cumulative displacement of the femoral and the acetabular articulating surface in zones 2 to 5. This displacement indicates a shortening of the neck plus a medio-cranial displacement of the acetabular articulating surface and was 4.3 mm, 7.5 mm, 9.4 mm and 7.7 mm (zone 2–5). The radiographic center of rotation (COR) was significantly medialised (mean 6.2 mm) and displaced in the cranial direction (mean 6.9 mm) (p< 0.00001). The mean total (femoral plus acetabular) horizontal and vertical offset change was 6.4 mm and 9.5 mm respectively (p< 0.00001). There was a significantly higher vertical offset change in the acetabulum than in the femur (p=0.0006). This resulted in a significantly larger change in vertical than in horizontal offset (p=0,04). Conclusion: The displacement of the acetabular COR was responsible for 60% of the total vertical and 99% of the total horizontal offset change. The femoral side did not compensate for this displacement. SRA did not restore the biomechanics of the native hip

Total hip arthroplasty is among the most successful interventions in all of medicine and has recently been termed “The Operation of the Century”. Charnley originally stated that “Objectives must be reasonable. Neither surgeons nor engineers will ever make an artificial hip joint that will last 30 years and at some time in this period enable the patient to play football.” and he defined the appropriate patient as generally being over 65 years of age. Hip rating scales developed during this time were consistent with this approach and only required relief of pain and return to normal activities of daily living to achieve a perfect score. Since this time, however, hip arthroplasty has been applied to high numbers of younger, more active individuals and patient expectations have increased. One recent study showed that in spite of a good hip score, only 43% of patients had all of their expectations completely fulfilled following THA. The current generation of metal-metal hip surface replacement arthroplasty (SRA) has been suggested as an alternative to standard THA which may offer advantages to patients including retention of more native bone, less stress shielding, less thigh pain due to absence of a stem, less limb length discrepancy, and a higher activity level. A recent technology review by the AAOS determined that currently available literature was inadequate to verify any of these suggested potential benefits. The potential complications associated with SRA have been well documented recently. The indications are narrower, the implant is more expensive, the technique is more demanding and less forgiving, and the results are both highly product and surgeon specific. Unless a clinical advantage in the level of function of SRA over THA can be demonstrated, continued enthusiasm for this technique is hard to justify. To generate data on the level of function of younger more active arthroplasty patients, a national multicentre survey was conducted by an independent university medical interviewing centre with a long track record of conducting state and federal medical surveys. All patients were under 60, high demand (pre-morbid UCLA score > 6) and had received a cementless stem with an advanced bearing surface or an SRA at one of five major total joint centres throughout the country. The detailed questionnaire quantified symptoms and function related to employment, recreation, and sexual function. Patients with SRA had a higher incidence of noises emanating from the hip than other bearing surfaces although this was transient and asymptomatic. SRA patients were much more likely to have less thigh pain than THA, less likely to limp, less likely to perceive a limb length difference, more likely to run for exercise, and more likely to run longer distances. While some or most of the observed advantages of SRA over THA may be attributable to some degree of selection bias, the inescapable conclusion is that SRA patients are demonstrating clinical advantages that warrants continued utilisation and investigation of this procedure

Fifteen patients with rheumatoid arthritis had 19 elbow arthroplasties with the Wadsworth type of surface replacement prosthesis. After a follow-up period averaging 30 months, 11 patients with 15 elbow arthroplasties were entirely satisfied with their freedom from pain and range of movement. Radiologically, however, the humeral component was loose in 10 of the 19 elbows and the ulnar component in 5. Two patients had reoperation, one to remove a prosthesis for early deep infection and one to exchange a humeral component which was loose. The risk of mechanical loosening is reduced by accurate positioning of the humeral component, but there is a high potential for failure. Changes in the design of the prosthesis and better instrumentation for alignment of the components are desirable. Prosthetic replacement of the elbow should still be regarded as experimental

We evaluated the results of Cementless Surface Replacement Arthroplasty (CSRA) of the shoulder in 67 patients with advanced glenohumeral destruction who have an intact rotator cuff. Between november 2002 and december 2008, 70 CSRA (32 Copeland/ Biomet and 38 SMRR/ Lima) were implanted in 67 patients. A deltopectoral approach was used in 34 cases and an anterosuperior approach in 36 cases. Patients were assessed using Constant score, a patient satisfaction score and a detailed radiographic analysis. The mean follow up was 3.4 years (range 1 to 7.5 years). The mean Constant score improved preoperatively from 17.6 points (range 2–55) to an average postoperative score of 66.1 (range 13–91). The pain score improved from 1.13 points (range 0–6) to 12.3 points (range 3–15). The forward flexion and external rotation improved from 71° (range 20 to 140) and 0° (range −40 to +45) to 143° (range 60 to180) and 34.4° (range −20 to +60) respectively. Complications included: 1 subscapularis detachment, 5 secondary rotator cuff tear, 1sepsis, 3 patients with shoulder stiffness. No shift in implant position was observed. 11 humeral components developed radiolucencies at the prosthesis-bone interface. The radiographic analysis involved a system of dividing the prosthesis/bone interface into 5 zones. The best clinical results were significantly achieved in patients with necrosis compared with osteoarthritis (Constant Score, ant. elevation, ext. Rotation). Using regression analysis we found that changes in the head-shaft angle position of the implant (valgus/varus placement of the CSRA) significantly predicted the age and sex adjusted Constant score. When the inclination angle of the humeral head decreases, the adjusted Constant score increases. In the same model, we also found that the lateral offset of the humerus significantly predicted the adjusted Constant score. When the lateral offset of the humerus decreases, the adjusted Constant score increases. The medialization of the glenoid significantly and negatively predicted the Constant score. Conclusion. CSRA of the shoulder outcomes have been comparable with those of stemmed arthroplasties. Radiolucent lines occur with follow up and most of the time located in the S1 area. Glenoid wear and humeral head lateralization negatively impact the clinical score. Cementless Shoulder resurfacing is a viable alternative to conventional shoulder arthroplasty

Heterotopic ossification (HO) occurs commonly after total hip arthroplasty (THA). Its severe form can result in impaired range of motion with reduced functional outcome. The rate and severity of HO after hip surface replacement arthroplasty (SRA) have never been well studied. Two hundred and ten hips were randomised to receive uncemented metal-on-metal THA or metal-on-metal SRA. Standard radiographs of the pelvis were assessed for HO by two reviewers at the latest follow-up (minimum of six months), using Brooker severity grading and Kjaersgaard-Andersen regional classification. The incidence of HO was 38.5% in the SRA group compared to 32.6% in the THA group (p=0.5). However, there was a significant difference in severity grades for the two groups (chi square, p=0.02). According to Brooker’s classification, nearly half of HO was of grade two in SRA and of grade one in THA. SRA was associated with significantly higher rates of severe HO (grades three and four) than THA (12.5% vs. 2.2%; p=0.009). Inter-rater agreement for Brooker grading was excellent (Cohen’s kappa, 0.88; p< 0.01). The incidence of HO after hip arthroplasty seems to be determined by patient-related factors. However, HO severity appears to be associated with local surgical factors and thereby SRA may result in more severe HO than THA. An extensive surgical approach, additional soft tissue release and the blunt damage occurring in gluteal muscles with SRA may signal the induction of more severe HO. Peri-operative deposition of bone debris derived from femoral head preparation may also play a role by transplanting osteoprogenitor cells. Surgeons must be aware of this risk of severe HO when offering SRA as an alternative treatment to younger patients. Routine prophylaxis with NSAIDs needs to be considered in these patients. A meticulous surgical technique to reduce muscle damage, pulsed lavage to clear bone debris, and debridement of necrotic tissue, may help to decrease the risk of severe HO in SRA

During the past fifty years metal hip implants have been used in orthopaedics. While these implants are considered biologically inert, several studies indicated that prosthetic implants could release metal ions following wear. The aim of this study was to evaluate serum and urine concentrations of metal ions in patients treated with hybrid surface replacement of the hip. Co, Cr, Mn, Mo, and Ni in the serum and urine of 14 patients and 19 controls were quantified by Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICP-MS). A Spectrometer ELEMENT (Finnigan MAT, Bremen, Germany) was used at the following resolution: 98Mo, 100Mo, (m/D;m = 300); 52Cr, 53Cr, 55Mn, 59Co, 60Ni, (m/D;m = 3000). The internal standard method (In) was applied to correct the random fluctuations of the signal. Indium was added to the sample solutions so as to reach a final concentration of 1 ng mL-1. Limits of Detection were calculated on the basis of the 3=555; criterion for 10 replicate measurements of solutions containing dilute pooled blood serum and dilute pooled urine, and recovery was obtained by quantifying the analytes of interest in spiked serum and urine. Recoveries of the elements ranged between 94.6% (serum Cr) and 118% (urine Ni). Data support the assumption that the concentrations of Co and Cr (the major components of the alloy) are substantially higher in serum and urine of patients than in those of controls while for the other elements no specific trend could be observed. Actually there isn’t any explanation on the possible biological consequences related to the increase of the metal ions levels although many hypothesis have been made. Further studies are thus mandatory to clarify this pattern

Introduction: Heterotopic ossification (HO) occurs commonly after total hip arthroplasty (THA). Its severe form can result in impaired range of motion with reduced functional outcome. The rate and severity of HO after hip surface replacement arthroplasty (SRA) have never been well studied. Methods: Two hundred and ten hips (194 patients) were randomized to receive uncemented metal-on-metal THA (103) or metal-on-metal SRA (107). Standard antero-posterior radiographs of the pelvis were assessed for HO by 2 reviewers at the latest follow-up (minimum of 6 months), using Brooker severity grading and Kjaersgaard-Andersen regional classification. Results: Pre-operative and post-operative data were similar for both groups. The incidence of HO was 38.5% in the SRA group compared to 32.6% in the THA group (p=0.5). However, there was a significant difference in severity grades for the 2 groups (chi square, p=0.02). According to Brooker_s classification, nearly half of HO was of grade 2 in SRA and of grade 1 in THA. SRA was associated with significantly higher rates of severe HO (grades 3 and 4) than THA (12.5% vs. 2.2%; p=0.009). Inter-rater agreement for Brooker grading was excellent (Cohen_s kappa, 0.88; p< 0.01). HO in SRA involved both the central and lateral regions in 26% of cases, whereas only 3% of HO in THA showed such a pattern (p=0.025). Risk factors, such as male gender, osteoarthritis, bilateral predilection, and previous history of HO, were observed in both groups. Patients with HO had reduced internal hip rotation (16.4° vs. 22.2°; p=0.02) and a higher incidence of postoperative hip pain (52% vs. 30%; p=0.04), but comparable functional outcome scores. Discussion: The incidence of HO after hip arthroplasty seems to be determined by patient-related factors. However, HO severity appears to be associated with local surgical factors and thereby SRA may result in more severe HO than THA. An extensive surgical approach, additional soft tissue release and the blunt damage occurring in gluteal muscles with SRA may signal the induction of more severe HO. Peri-operative deposition of bone debris derived from femoral head preparation may also play a role by transplanting osteoprogenitor cells. Surgeons must be aware of this risk of severe HO when offering SRA as an alternative treatment to younger patients. Routine prophylaxis with NSAIDs needs to be considered in these patients. A meticulous surgical technique to reduce muscle damage, pulsed lavage to clear bone debris, and debridement of necrotic tissue, may help to decrease the risk of severe HO in SRA

The aim of this studdy was to examine the effect of cementless surface replacement shoulder arthroplasty (CSRA) on proximal humeral anatomy in eroded shoulder joints. AP radiographs of 39 shoulders in 37 patients that underwent CSRA for arthritis were examined for geometry of the glenohumeral joint with correction for the magnification of our apparatus. Thirty-two were hemiarthroplasties and seven were total shoulder replacements (TSR). Average age was 70 years (range: 29–88 years). Mean clinical and radiological follow-up was 38 month (range: 24–72 months) and 16 months (range: 10–65 months) respectively. We measured reliable values on the proximal humerus and the lateral glenohumeral offset (LGHO) relative to the coracoid base. Preoperative and last follow-up Constant scores were recorded. Based on anatomical data with respect to humeral head radius there was a mean 6mm preoperative loss in LGHO (95% CI 3.6–8.8, p< 0.01). The mean value of 53mm increased postoperatively to 59mm and was 57mm at last follow-up. The mean changes were an increase of 6mm (95% CI 4.4–8.5, p< 0.01) and then a decrease of 2mm (95% CI 0.1–5.4, p=0.04) respectively. The lever arm, measured from the greater tuberosity to the centre of instant rotation, increased a mean 5mm post-operatively (95% CI 3.8–6.4, p< 0.01) with no significant fall at last follow-up. Humeral head size and medial offset relative to shaft width increased by 13% and 30% respectively. The humeral head centre moved superiorly relative to the glenoid a mean 2mm after operation (95% CI −0.2–3.5, p=0.08) and a further 1mm at last follow-up (95% CI −0.1–3.0, p=0.07). Forward flexion and abduction improved from 66′ and 58′ preoperatively to 124′ and 112′ postoperatively, with age/ sex-adjusted Constant scores increasing by 53 (95% CI 43.0–64.4, p< 0.01) from a mean 25 preoperatively to 79 at last follow-up. For hemiarthroplasty the LGHO increased by 9% and for TSR by 24%, with greater increases in flexion and abduction in the latter group. The Copeland CSRA is centred on the native humeral neck for head version and offset. This preserves maximal bone stock and avoids the need for modularity which some modern stemmed prostheses use to reconcile differences between proximal shaft and humeral head anatomy. The inherent limitation is the requirement for preservation of sufficient humeral head to permit resurfacing. In this group with fairly marked degrees of joint erosion the CSRA, using autogenous bone graft and prostheses of variable width, achieved statistically and clinically significant increases in the lever arm. The improved biomechanics and soft tissue tension correlated to a good clinical outcome with no evidence of significant early subsidence

INTRODUCTION: Improved factors influencing component wear with regards to bearing surfaces, metallurgy, tribology, and manufacturing technology allowed reintroduction of metal-on-metal (MOM) articulation in total hip arthroplasty (THA) and surface replacement arthroplasty (SRA). MATERIALS AND METHODS: Sixty three patients were implanted with a forged, high carbon content, chrome-cobalt, MOM SRA component (Durom, Zimmer, USA). Samples of whole blood and serum were collected pre-operatively and, post-operatively at three months, six months one year and two years. Chromium and cobalt concentrations were measured using a a high-resolution, sector-field, inductively-coupled plasma mass spectrophotometer (HR-SF-ICP-MS). RESULTS: At two years, whole blood levels were Cr 1.25 umol/L (SD 0.55), Co 0.62 umol/L (SD 0.26). In comparison to the pre-operative levels, the levels increased significantly for both elements Cr 1.3X, Co 5.0 X. Component size was inversely proportional to the chromium and cobalt ion levels at one year post operatively (ANOVA regression analysis, p = 0.0404, for Co and p = 0.0156 for Cr). Other factors such as age and activity level did not correlate with the metal ions levels. DISCUSSION AND CONCLUSION: Chromium and cobalt metal ions measured in patients following implantation of the high carbon content, forged, metal on metal SRA implants used in this study are very low in comparison to other published results with different SRA implants. We believe that these encouraging results found with the SRA components used are resultant of favourable manufacturing and tribologic factors such as low surface roughness, high carbon content, forged chromium and cobalt material, component clearance, and optimum component sphericity. The results of this study are also in accordance with the concepts of reduced wear with larger diameter MOM articulations

Introduction. A metal ion study was undertaken in patients who had received an articular surface replacement. The design of these components is optimised in line with lubrication theory and produces low levels of wear in hip joint simulators. Methods. Patients were recruited in four centres. Whole blood samples were analysed for metal ion levels using high resolution ICP-MS (inductively coupled plasma mass spectrophotometry). A total of 75 patients was enrolled into the study and 65 and 47 patients were assessed after 12 and 24 months implantation respectively. Results are included irrespective of clinical outcome. Results. The 12 and 24 month median ion levels were 1.4 μg/l and 1.6 μg/l respectively for chromium and 1.5(μg/l and 1.6 μg/l respectively for cobalt. The pre-operative levels were 0.38(μg/l and 0.34(μg/l for chromium and cobalt respectively. Twenty-seven percent of patients had a pre-operative chromium level that was higher than the 24 month median level. Similarly the value for cobalt was seven percent. However close examination of the data shows that it is skewed by 6 outliers with cobalt or chromium levels greater than 10(μg/l after 24 months implantation. This appears to be related to acetabular component placement. Patients with acetabular components implanted at a high inclination angle (>55deg) are more likely to have elevated metal ion levels compared with a standard angle (<55deg). In the 24 month group two patients (both outliers) have been revised. Furthermore, the high metal ion levels at 24 months could be predicted by intermediate levels after 12 months. Conversely those levels below 10ug/l had already stabilised after 12 months in vivo. Conclusion. Large diameter metal-on-metal bearing with optimised tolerances can produce very low blood metal ion levels. However, in line with other studies, mal-positioning of components may lead to significantly elevated levels of wear and hence blood metal ions

Introduction. While fixation on the acetabular side in resurfacing implants has been uncemented, the femoral component is usually cemented. The most common causes for early revision in hip resurfacing are femoral head and or neck fractures and aseptic loosening of the femoral component. Later failures appear to be more related to adverse soft-tissue reactions due to metal wear. Little is known about the effect of cementing techniques on the clinical outcome in hip resurfacing, since retrieval analysis of failed hip resurfacing show large variations. Two cementing techniques have dominated. The indirect low viscosity (LV) technique as for the Birmingham Hip resurfacing (BHR) system and the direct high viscosity (HV) technique as for the Articular Surface replacement (ASR) system. The ASR was withdrawn from the market in 2010 due to inferior short and midterm clinical outcome. This study presents an in vitro experiment on the cement mantle parameters and penetration into ASR resurfaced femoral heads comparing both techniques. Methods. Five sets of paried frozen cadavar femura (3 male, 2 female) were used in the study. The study was approved by ethics committee. Plastic ASR replicas (DePuy, Leeds, UK), femoral head size 47Ø were used. The LV technique was used for the right femora (Group A, fig. 1 and 3) while the HV technigue was used for the left femora (Group B. Fig 2 and 4). The speciments were cut into quadrants. An initiial visual, qualitative evaluation was followed by CT analysis of cement mantle thickness and cement penetration into bone. Results. No significant differences were seen between the four quadrants within each group. The LV technigue resulted in greater cement penetration and increased cement mantle under the top proximally. The HV technique showed less penetration and lower cement mantle. See figures 1–4. Discussion. The aim was to analyze the effect of the cementing techniques used in hip resurfacing practice. The ASR implant was chosen to improve understanding of whether the implant may have been sensitive to cementing techniques and whether an analysis of cementing with the recommended HV technique may assist in explaning the high incidence of short-term ASR revisions due to fractures. Findings for the HV technigue would indicate a superior technique according to consensus in conventional arthropalsty However, this contradicts clinical evidence on resurfacing, where LV cementation has been shown tho be superior. The superficial intergration in the HV technigue may result in only a superficial integration and subsequently suboptimal fixation to bone. To view tables/figures, please contact authors directly