The aim of this study is to analyse the radiological outcomes and predictors of avascular necrosis following 2-hole DHS in Garden I and II neck of femur fractures in patients more than 60 years with a minimum follow up of one year. We retrospectively reviewed 51 consecutive patients aged more than 60 years who underwent DHS fixation for Garden I and II fractures. Demographics, fracture classification, time to surgery, pre-operative AMTS, preoperative posterior tilt angle, quality of reduction, pre and post-operative haemoglobin(hb), creatinine and comorbidities were analysed for correlation with AVN using Chi-Square test, Independent Sample and paired t test. There were 40 (78.4%) females and the mean age of the cohort was 77 years. 28 and 23 were Garden I and II NOF fractures respectively. Union was observed in all our patients except one(kappa =1). 12/51(23.5%) developed AVN of the femoral head. Statistically significant higher incidence of AVN was noted in patients with a pre-op tilt angle > 200 (p = 0.006). The mean drop in Hb was higher in patients who developed AVN (21.5 g/L) versus the non-AVN group (15.9 g/L) (p = 0.001). There was no difference in AVN rates with respect to laterality, mean time to surgery, pre-op AMTS and Charlson comorbidity index. 4/52 (7.6%) had re-operations (one hardware prominence, two conversions to arthroplasty, one fixation failure during the immediate post-op period). The 30-day and one year mortality rates were 1.9 % and 11.7 % respectively. 2-hole DHS fixation in undisplaced NOF fractures has excellent union rates. A pre-operative posterior tilt angle of >200 and a greater difference in pre and post operative haemoglobin were found to correlate positively with the progression to AVN . No correlation was observed between AVN and time to surgery, laterality, quality of reduction and comorbidities

The risk of AVN is high in Unstable Slipped Capital Femoral Epiphysis (SCFE) and the optimal surgical treatment remains controversial. Our AVN rates in severe, unstable SCFE remained unchanged following the introduction of the Modified Dunn Procedure (MDP) and as a result, our practice evolved towards performing an Anterior Open Reduction and Decompression (AOR) in an attempt to potentially reduce the “second hit” phenomenon that may contribute. The aim of this study was to determine the early surgical outcomes in Unstable SCFE following AOR compared to the MDP. All moderate to severe, Loder unstable SCFEs between 2008 and 2022 undergoing either an AOR or MDP were included. AVN was defined as a non-viable post-operative SPECT-CT scan. Eighteen patients who underwent AOR and 100 who underwent MPD were included. There was no significant difference in severity (mean PSA 64 vs 66 degrees, p = 0.641), or delay to surgery (p = 0.973) between each group. There was no significant difference in the AVN rate at 27.8% compared to 24% in the AOR and MDP groups respectively (p = 0.732). The mean operative time in the AOR group was 24 minutes less, however this was not statistically significant (p = 0.084). The post-reduction PSA was 26 degrees (range, 13–39) in the AOR group and 9 degrees (range, -7 to 29) in the MDP group (p<0.001). Intra-operative femoral head monitoring had a lower positive predictive value in the AOR group (71% compared to 90%). Preliminary results suggest the AVN rate is not significantly different following AOR. There is less of an associated learning curve with the AOR, but as anticipated, a less anatomical reduction was achieved in this group. We still feel that there is a role for the MDP in unstable slips with a larger remodelling component

Abstract. Background. The aim of this study is to analyse the radiological outcomes and predictors of avascular necrosis following 2-hole DHS in Garden I and II neck of femur fractures in patients >60 years with a minimum follow up of one year. Methods. We retrospectively reviewed 51 consecutive patients >60 years who underwent DHS fixation for Garden I and II fractures. Demographics, fracture classification, time to surgery, pre-operative AMTS, preoperative posterior tilt angle, quality of reduction, pre and post-operative haemoglobin (hb), creatinine and comorbidities were analysed. Results. There were 40 (78.4%) females and the mean age was 77 years. 28 and 23 were Garden I and II NOF fractures respectively. Union was observed in all our patients except one. 12/51(23.5%) developed AVN of the femoral head. Statistically significant higher incidence of AVN was noted in patients with a pre-op tilt angle > 20. 0. (p = 0.006). The mean drop in Hb was higher in patients who developed AVN (21.5 g/L) versus the non-AVN group (15.9 g/L) (p = 0.001). There was no difference in AVN with respect to laterality, mean time to surgery, pre-operative AMTS and Charlson comorbidity index. 4/52 (7.6%) had re-operations. The 30-day and one year mortality were 1.9 % and 11.7 % respectively. Conclusion. In our series a preoperative posterior tilt angle of >20. 0. and a drop in haemoglobin were found to correlate with the progression to AVN. No correlation was observed between AVN and time to surgery, laterality, quality of reduction and comorbidities

INTRODUCTION. Stimulation of angiogenesis via the delivery of growth factors (GFs) like vascular endothelial growth factor (VEGF) is a promising strategy for the treatment of avascular necrosis (AVN). Tyraminated poly-vinyl-alcohol hydrogels (PVA-Tyr), which have the ability to covalently incorporate GFs, were proposed as a platform for the controlled delivery of therapeutic levels VEGF to the necrotic areas[1]. Nevertheless, PVA hydrophilicity and bioinertness limits its integration with the host tissues. The aim of this study was to investigated the effectiveness of incorporating gelatin, an FDA-approved, non-immunogeneic biomaterial with biological recognition sites, as a strategy to facilitate blood vessels invasion of PVA-Tyr hydrogels and to restore the vascular supply to necrotic tissues. METHODS. Progressively higher gelatin concentrations (0.01–5wt%) were incorporated in the PVA-Tyr network. Hydrogel physico-chemical properties and endothelial cell attachment were evaluated. Afterwards, the capability of the released VEGF and gelatin to promote vascularization was evaluated via chorioallantoic membrane (CAM) assay. VEGF-loaded PVA-Tyr hydrogels with or without gelatin (n=7) were implanted in a subcutaneous mouse model for 3 weeks. Vascularization (CD31+ cells) and cell infiltration (H&E) were evaluated. Finally, AVN was induced in 6 weeks old male piglets as previously described [2]. A transphyseal hole (3mm) was drilled and PVA-Tyr hydrogels with 1% gelatin were delivered in the defects. Piglets were euthanized after 4 weeks and microCT analysis was performed. RESULTS. The incorporation of 1% gelatin significantly enhanced cell attachment without compromising hydrogels physical properties, degradation time, VEGF retention and release. Thus, this gelatin concentration was selected for further analysis. Additionally, the covalent incorporation of VEGF or gelatin to the PVA-Tyr network does not hamper their bioactivity, as both still promoted neo-angiogenesis in a CAM assay. Following subcutaneous implantation, the presence of gelatin did not increase the cellular infiltration in the PVA-Tyr hydrogels. Nevertheless, higher vascular infiltration was observed in the groups where either gelatin or VEGF were included. Additionally, preliminary microCT results indicated that the delivery of PVA-Tyr hydrogels containing 1% gelatin in an AVN model was effective in preventing the necrosis-associated resorption of the bone. DISCUSSION & CONCLUSIONS. These results indicated that the presence of either gelatin or VEGF was sufficient to promote vascular infiltration. Additionally, preliminary results suggested the suitability of the developed hydrogels to treat AVN

Introduction. Leg length discrepancy (LLD) in patients with unilateral developmental dysplasia of the hip (DDH) can be problematic for both patients and surgeons. Patients can acquire gait asymmetry, back pain, and arthritis. Surgical considerations include timing of correction and arthroplasty planning. This study audits standing long leg films performed at skeletal maturity in our patients. The aim of this study is to identify if surgical procedure or AVN type could predict the odds of needing an LLD Intervention (LLDI) and influence our surveillance. Materials and Methods. Hospital database was searched for all patients diagnosed with DDH. Inclusion criteria were patients with appropriately performed long leg films at skeletal maturity. Exclusion criteria were patients with non DDH pathology, skeletally immature and inadequate radiographs. All data was tabulated in excel and SPSS was used for analysis. Traumacad was used for measurements and AVN and radiologic outcome grades were independently classified in duplicate. Results. 110 patients were identified. The mean age of follow-up was 15 years with final average LLD of 1mm(±5mm). The DDH leg tended to be longer and length primarily in the femur. 31(28.2%) patients required an LLDI. 19 Patients had a final LLD >1.5cm. There was no statistical significant difference in the odds of needing an LLDI by type of surgical procedure or AVN. AVN type 4 was associated with greatest odds of intervention. The DDH leg was more likely to require ipsilateral epiphysiodesis or contralateral lengthening in Type 1 and 2 AVN. Conclusions. The DDH leg tends to be longer, leg lengths should be monitored, and leg length interventions are frequently required irrespective of previous DDH surgical procedure or the presence of AVN

Avascular necrosis (AVN) of the femoral head is a potentially devastating complication of treatment for developmental dysplasia of the hip (DDH). AVN most commonly occurs following operative management by closed (CR) or open reduction (OR). This occurrence has frequently been examined in single centre, retrospective studies, however, little high-level evidence exists to provide insight on potential risk factors. The purpose of this observational, prospective multi-centre study was to identify predictors of AVN following operatively-managed DDH. A multi-centre, prospective database of infants diagnosed with DDH from 0–18 months was analyzed for patients treated by CR and/or OR. At minimum one year follow-up, the incidence of AVN (Salter criteria) was determined from AP pelvis radiographs via blinded assessment and consensus discussion between three senior paediatric orthopaedic surgeons. Patient demographics, clinical exam findings and radiographic data were assessed for potential predictors of AVN. A total of 139 hips in 125 patients (102 female, 23 male) underwent CR/OR at a median age of 10.4 months (range 0.7–27.9). AVN was identified in 37 cases (26.6% incidence) at a median 23 months post-surgery. Univariate logistic regression analysis comparing AVN and no AVN groups identified sex, age at diagnosis, age at surgery, pre-surgery IHDI grade and time between diagnosis and surgery as potential predictive factors. Specifically, male sex (OR 2.21 [0.87,5.72]), IHDI grade IV, and older age at diagnosis (7.4 vs. 9.5 months) and surgery (10.2 vs. 13.6 months) were associated with development of AVN. Likewise, increased time between diagnosis and surgery (2.9 vs. 5.5 months) was also associated with a higher incidence. No association was found with surgery type (CR vs. OR), pre-surgery acetabular index or surgical hip. Development of AVN occurred in 26.6% of hips undergoing CR or OR at a median 23 months post-surgery. Male sex, older age at diagnosis and surgery, dislocation severity and increased time between diagnosis and surgery were associated with AVN. Longer-term follow-up and larger numbers will be required to confirm these findings. Early outcomes from this prospective patient cohort suggest that AVN is an important complication of operative management for DDH, and appears to occur at a comparable rate whether the reduction is performed open or closed. Male patients may be more susceptible to developing AVN and merits further exploration. Potential predictive factors of older age and length of time between diagnosis and surgery emphasize the importance of early detection and treatment to minimize complications and optimize outcomes

INTRODUCTION. Avascular necrosis (AVN) of the femoral head (FH) initiates from biological disruptions in the bone and may progress to mechanical failure of the hip. Mechanical and structural properties of AVN bone have not been widely reported, however such understanding is important when designing therapies for AVN. Brown et al.[1] assessed mechanical properties of different regions of AVN FH bone and reported 52% reduction in yield strength and 72% reduction in elastic modulus of necrotic regions when compared to non-necrotic bone. This study aimed to characterise structural and mechanical properties of FH bone with AVN and understand the relationship between lesion volume and associated mechanical properties. METHODS. Twenty FH specimens from patients undergoing hip arthroplasty for AVN and six non-pathological cadaveric FH controls were collected. Samples were computed tomography scanned and images analysed for percentage lesion volume with respect to FH volume. Samples were further divided for structural and mechanical testing. The mechanical property group were further processed to remove 9mm cylindrical bone plugs from the load bearing and non-load-bearing regions of the FHs. FH and bone plug samples were tested in compression (1mm/min); elastic modulus and yield stress were calculated. RESULTS. Imaging. Individual lesion size within AVN FHs varied: multiple small lesions or small numbers of large lesions were present in all FHs. Mean lesion volume percentage for AVN FHs was significantly greater than control FHs (p30% total FH volume. Structural Properties: The mean elastic modulus for AVN FHs was 15% lower than that of control FHs and mean yield stress was 4% lower than that of control FHs, however this difference was not significant. Mechanical Properties. The mean elastic modulus and yield stress of bone plugs from the load-bearing regions of AVN FHs were significantly lower than those of control samples (79% and 77% respectively; p<0.05, Kruskal-Wallis), however, for non-load-bearing samples, mean elastic modulus and yield stress of AVN FHs were significantly higher than control samples (by 153% and 123% respectively; p<0.05, Kruskal-Wallis). DISCUSSION. Although mechanical properties of bone in load-bearing regions of AVN FHs were significantly less than those of control FHs, replicating previous findings by Brown et al. (1981, CORR. 156, 240-7), mechanical properties in the non-load bearing regions were increased. This may be due to adaptation of the non-load bearing region to support loads following AVN in normally load bearing regions, or due to the presence of denser sclerotic tissue. In this study, necrotic bone samples demonstrated smaller changes in mechanical properties in the load-bearing region with respect to those regions in the control samples than previously reported by Brown et al.. This may be due to differences in experimental methods (e.g. patient demographics, quality of control bone samples, loading rate, and location of samples) or due to the disease stage of the AVN FHs from which tissues were taken. In addition, this study has demonstrated that necrotic lesions are not consistent in quantity, size and location

Despite recent advances in the management of slipped capital femoral epiphysis (SCFE), controversy remains about the treatment of choice for unstable slips. Surgical dislocation and open reduction has the advantage of identifying and preserving the blood supply of femoral head thereby potentially reducing the risk of avascular necrosis, (AVN). There is large variation in the literature from several small series about reported AVN rates ranging from two to 66% for unstable SCFE treated with surgical dislocation. The aim of our study was to analyze our experience with acute open reduction and internal fixation of unstable acute and unstable acute on chronic slips using the technique of surgical dislocation described by Professor Reinhold Ganz. A retrospective review of 11 patients (12 hips) treated by surgical dislocation, reduction and pinning as the primary procedure for unstable acute and unstable acute on chronic SCFE in a tertiary referral children's hospital was undertaken. This represents the entire series treated in this manner from September 2007 to January 2018. These procedures were performed by a team of Orthopaedic surgeons with significant experience performing surgical dislocation of the hip including patients with chronic SCFE, Perthes' disease, impingement and acetabular fractures. Demographic data, intraoperative records, postoperative notes and radiographs including details of subsequent surgery were reviewed. There were seven boys and four girls with mean age of 13.4 years, range 11 to 15 years at the time of surgical dislocation. Out of 12 hips, two had acute unstable slip while the remaining 10 had acute on chronic unstable slip. Six patients had good or excellent results. The remaining six patients developed AVN of which three patients had total hip replacement at six months, 17 months and 18 months following primary procedure. Seven patients required more than one operation. Three patients lost their correction and required re fixation despite surgical dislocation, reduction and fixation being their primary procedure. This series demonstrates a high percentage of AVN (50%) in severe unstable SCFE treated with surgical dislocation despite careful attention to retinacular flap development and intra operative doppler studies. This is in direct contrast to our experience with subcapital reorientation with surgical dislocation in stable slips where excellent results were achieved with a low rate of AVN. Pre-operative imaging with MRI and perfusion studies may identify where ischemia has occurred and might influence operative treatment. Based on our results, we do not recommend routine use of surgical dislocation in unstable SCFE. This technique requires further scrutiny to define the operative indications in unstable SCFE

Unstable slipped capital femoral epiphysis (SCFE) has an increased incidence of avascular necrosis (AVN). The purpose of this study was to determine if early identification and intervention for AVN may help preserve the femoral head. We retrospectively reviewed 48 patients (50 hips) with unstable SCFE managed between 2000 and 2014. Based on two different protocols during the same time period, 17 patients (17 hips) had a scheduled MRI between 1 and 6 months from initial surgery, with closed bone graft epiphysiodesis (CBGE) or free vascularised fibular graft (FVFG) if AVN was diagnosed. Thirty-one patients (33 hips) were evaluated by plain radiographs. Outcomes analysed were Steinberg classification and subsequent surgical intervention. We defined Steinberg class IVC as failure in treatment because all of the patients referred for osteotomy, arthoplasty, or arthrodesis in our study were grade IVC or higher. Overall, 13 hips (26%) with unstable SCFE developed AVN. MRI revealed AVN in 7 of 17 hips (41%) at a mean of 2.5 months postoperatively (range, 1.0 to 5.2 months). Six hips diagnosed by MRI received surgical intervention (4 CBGE, 1 FVFG, and 1 repinning due to screw cutout) at a mean of 4.1 months (range, 1.3 to 7.2 months) postoperatively. None of the 4 patients treated with CBGE within two months postoperatively progressed to stage IVC AVN. The two patients treated after four months postoperatively both progressed to stage VC AVN. Radiographically diagnosed AVN occurred in 6 of 33 hips (18%) at a mean of 6.8 months postoperatively (range, 2.1 to 21.1 months). One patient diagnosed with stage IVB AVN at 2.4 months had screw cutout and received CBGE at 2.5 months from initial pinning. The remaining 5 were not offered surgical intervention. Five of the 6 radiographically diagnosed AVN, including the one treated with CBGE, progressed to stage IVC AVN or greater. None of the 4 patients with unstable SCFE treated with CBGE within 2 months post pinning developed grade IVC AVN, while all patients treated with other procedures after 2 months developed IVC or greater AVN. Early detection and treatment of AVN after SCFE may alter the clinical and radiographic progression

Reverse Total shoulder arthroplasty (RTSA) was initially introduced to treat rotator cuff arthropathy. With proven successful long-term outcomes, it has gained a noteworthy surge in popularity with its indications consequently being extended to treating various traumatic glenohumeral diseases. Several countries holding national registries remain a guide to the use the prosthesis, however a notable lack of epidemiological data still exists. More so in South Africa where the spectrum of joint disease related to communicable diseases such as HIV and tuberculosis may influence indications and patient demographics. By analysing the epidemiology of patients who underwent RTSA at our institution, we aimed to outline the local disease spectrum, the patients afflicted and indications for surgery. A retrospective review of all patients operated within the sports unit between 1 January 2019 and 31 December 2022 was conducted. An analysis of the epidemiological data pertaining to patient demographics, diagnosis, indications for surgery and complications were recorded. Included in the review were 58 patients who underwent primary RTSA over the 4-year period. There were 41 females and 17 male patients, age <55 years (n= 14) >55 years (n=44). The indications included 23 rotator cuff arthropathy (40%), 12 primary glenohumeral osteoarthritis (OA) (20%), 10 avascular necrosis (AVN) humeral head (17%), 7 inflammatory OA (12%), 4 chronic shoulder dislocation (7%) and 2 sequalae of proximal humerus fractures (4%). The study revealed RTSA being performed in patients older than 55 years of age, the main pathologies included rotator cuff arthropathy and primary OA, however AVN and shoulder dislocations secondary to trauma contributed significantly to the total tally of surgeries undertaken. This highlights the disease burden of developing countries contributing to patients presenting for RTSA

Aim. (1) To determine whether any difference exists in AVN risk between surgical reduction [Fish] or pinning-in-situ [PIS] of severe slips. (2) To review the different classifications of SUFE in relation to AVN. Materials and Methods. 56 children presented with slipped upper femoral epiphysis (SUFE) from 1998 to 2008; 29 males, 27 females; mean age 12.8 years. The Loder & Southwick classifications were used. All slips were treated surgically. The mild and moderate groups were treated with a single pin-in-situ. The severe group had either surgical reduction [Fish femoral neck osteotomy], alternatively a single pin-in-situ, randomised by day of admission. Avascular necrosis of the femoral head (AVN) was the primary outcome measurement. Results. There were seven cases of AVN (12.5%). 2/41 in the stable group developed AVN compared to 5/15 in the unstable group, statistically significant [Chi-Square P=0.001]. No patient in the mild group, one out of seven in the moderate group, and six out of 22 in the severe group developed AVN. In the severe slip group, the AVN rate in the PIS group was 40%, after Fish osteotomy it was 23.5%. This is not statistically significant, but the trend favours surgical reduction. Conclusion and Significance. (1) Surgical reduction by Fish osteotomy is no riskier for AVN than pinning in situ for severe SUFE. Surgical reduction should therefore be performed to avoid gross deformity in these cases. (2) We have confirmed that the stability and the severity of the slip at presentation are the best indicators for predicting AVN

Introduction:. Recent studies have concluded that gender influences hip morphology at the time of surgery as well as dysplastic development of the hip. This may lead to a particular choice of implant including stem design and/or neck modularity. In this study we hypothesized that not only gender but also morphotype and etiology (primary osteoarthritis versus aseptic osteonecrosis) may be a significant factor to predict the anatomy of the hip at the time of total hip arthroplasty (THA). Methods:. We reviewed 690 patients undergoing THA for primary arthritis (OA) or avascular osteonecrosis (AVN) between April 2000 and June 2005 and stratified each into three groups based on their anatomic constitution: endomorph (EN), ectomorph (ECT), or mesomorph (ME) (determined by the ratio: pelvic width/total leg length measured on full-length X-rays). Two independent observers measured twice four parameters on preoperative CT scan: neck-shaft-angle angle (NSA), femoral offset value (FO), helitorsion (Ht) value and femoral neck anteversion (Av). Results:. No significant difference were observed between men and women for the four parameters with respectively: NSA (129.29° ± 5.6 versus 129.3° ± 5.7), Av (20.3° ± 8.6 versus 20.27° ± 8.6), FO (19.7 mm ± 3.98 versus 19.74 mm ± 3.98) and Ht (19.97° ± 12.2 for men and 19.94° ± 12.3). Significant difference were found for NSA: 130.1° ± 5.8 for ECT, 129.55° ± 6 for MES and 128.2° ± 5,1 for EN with p < 0.01. For Av, the values were: 18.9° ± 8.7 for ECT, 20.74° ± 8.1 for MES and 21.2° ± 8.95 for EN (p < 0.01). For FO the values were 19.1 mm ± 3.9 for ECT, 19.7 ± 4 for MES and and 20.44 mm ± 3.93 for EN (p < 0.01). No difference was found for Ht between the 3 groups. A significant difference was found between patients suffering from OA and AVN: mean NSA was 130.36° ± 8.79 for OA patients versus 127.35° ± 8.38 for those who had an AVN (p < 0.01). A value was 17.06° ± 8.1 for OA and 23.7 ± 7.89 for AVN (p < 0.01). FO value was 18.72 mm ± 3.71 for OA versus 20.75 mm ± 4.15 for AVN (p <0.01). And Ht was 18.94° ± 9.64 for OA and 21.05° ± 14.5 for AVN patients (p < 0.01). Discussion and conclusion:. Patients with short and wide morphotype (endomorph) had, irrespective of gender, lower values of NSA with greater anterversion and offset values, whereas patients with long and narrow morphotype (ectomorph) had higher values of NSA and smaller Av and FO (figure 1). In the same time patients suffering from AVN have lower NSA angle, lower Av, smaller FO and Ht (figure 2). Femoral stem design should allow the consideration of these differences to optimize the reconstruction of the hip at the time of THA including pre-operative and intra-operative modularity

Introduction. The results of the Birmingham Hip Resurfacing (BHR) device in several series reveal that the predominant mode of failure is femoral neck fracture or femoral head collapse and that careful patient selection and precise operative technique are vital to the success of this procedure. In this report we consider the results of BHR in patients with severe arthritis secondary to femoral head AVN. Methods. This was a single-surgeon consecutive series of BHRs with a minimum follow-up of 5 years. Fifty-nine patients with Ficat-Arlet grade III or IV femoral head AVN (66 hips) and treated with BHRs at a mean age of 43.9 years (range 19 to 67.7 years) were followed up for 5.4 to 9.6 years (mean 7.1 years). No patient died and none was lost to follow-up. Revision for any reason was the end-point and unrevised patients were assessed with Oxford hip scores. They were also reviewed clinically and with AP and lateral radiographs. Results. There were five failures in this cohort, giving a failure rate of 7.6% and a cumulative survivorship of 86% at 9.6 years. In one further patient the femoral component has tilted into varus from further collapse of the femoral head. He is asymptomatic but knows that he will need a revision if he develops symptoms. No other patient shows clinical or radiological adverse signs. Discussion. Several studies have shown that the results of arthroplasty are generally worse in AVN as compared to those in osteoarthritis. Reviewing the above results it appears to us that the relatively poorer cumulative survival observed in patients with a diagnosis of AVN (86%) compared to those with other diagnoses make AVN a relative contraindication to the hip resurfacing procedure

Introduction. The Human immunodeficiency virus (HIV) has changed all aspects of orthopaedic practice in Durban, South Africa. In our Arthroplasty unit, we have noticed a significant increase in HIV positive patients that required total hip arthroplasty (THR). Method. We conducted a retrospective, demographic chart review of all patients below the age of 55years undergoing primary THR in our unit from 2004 to 2011. Results. The results show a steady rise from 22 THR's in 2004, to 51 in 2011. There was a demographic change in patients presenting with avascular necrosis (AVN) as primary diagnosis, with a significant increase of HIV positive patients. The new demographic group that makes up 44% of our current practice are black Africans, particularly females (70% of all black patients). The majority of them (66%) have none of the previous risk factors for AVN (alcohol, smoking and steroids) and out of this group 52% are HIV positive on anti-retroviral medication (ARV's) with an average CD4 count of 516. All HIV positive patients, in this demographic study, were black African females. Discussion. In the past, the typical patient receiving a primary THR for AVN in Durban was a young Asian male. These patients had strong associations with alcohol, smoking and oral steroid use. This demographic group makes up 33% of our current practice. Demonstrated clearly is a change in demographics of patient population and this lead to a number of interesting questions. What caused this sudden increase in HIV related AVN in our unit? To what extend do ARV's contribute to this accelerated progression of AVN and HIV?. This paper focuses our attention on HIV and its affect in modern orthopaedics. The challenge is great, the question remains … how will we respond?. NO DISCLOSURES

Introduction. Core decompression is used in precollapse lesions to forestall disease progression in avascular necrosis (AVN) of femoral head (FH). The author reports a new technique using reverse bone graft technique to effectuate core decompression. Aim. To prevent precollapse in Ficat Type 1&2 and revascularization using synthetic bone graft material. Methods. A 18 year female police trainee with Magnetic Resonance Imaging (MRI) confirming AVN Stage 2 Ficat, clinically painful hip not evident in x-rays consented to undergo this new technique. Reverse bone graft technique with a Coring reamer – Patent 5423823. A minimally invasive technique with lateral 2 cm incision introducing 8.5 mm core reamer to remove a core of bone up to the subchondral bone. The subchondral cyst decompressed and curetted under video recorded Image Intensifier (II). Demarcated avascular bone segment excised and bone graft reversed and inserted with cortical bone acting as a support to prevent collapse and the distal segment augmented using 5 grams of osteoconductive granular synthetic bone graft material based on calcium phosphate hydroxyapatite (HA 2500–5000 μm). Avascular segment histopathologically confirmed AVN. The metaphyseal entry was extrapoliated at the lateral cortex using the combined necrotic angle described by Kerboul in the anteroposterior and lateral views under II. Protected weight bearing for 2 months to prevent stress riser. Biomaterials. HA granules named as GranuMas™ developed under Intensified Research in Priority Areas (IRPA) Research Project (No. 03-01-03-0000-PR0026/05) and invented by the Advance Materials Research Centre (AMREC) and manufactured by GranuLab –Patent P1 20040748 fulfilling the criteria for American Society for Testing and Materials (ASTM) F1185-88(1993) Standards which is ‘Standard Specification for Composition of Ceramic Hydroxyapatite for Surgical Implants’. Derived from Malaysian limestone, ranging from 200–5000 μm gamma sterilized. Results. After 6 months, there was no collapse of subchondral bone and the FH showed revascularization along bone grafted site with viable graft and increased radiotracer activity using 99-Tc MDP Bone Planar Scintigraphy. Clinical analysis follow up at 2 years was descriptive rather than statistical with a x-ray evident incorporated graft and with pain free full range of movement. Discussion. Reduction in intraosseous pressure is achieved by using large bore 8.5 mm coupled with HA granules promoting revascularization. The core tract entering through the metaphyseal region reduces risk of subtrochanteric fracture a potential complication of vascularized fibular grafts and with less morbidity with other treatment methods for osteonecrosis of the femoral head. The concept can be extended in introducing stem cell and biologic material to treat AVN. Conclusion. This technique is minimally invasive and effective in young patients with early stage of FH AVN and has shown revascularization along the bone grafted site

INTRODUCTION. In total hip arthroplasty, preoperative planning is almost indispensable. Moreover, 3-dimensional preoperative planning became popular recently. Anteversion management is one of the most important factors in preoperative planning to prevent dislocation and to obtain better function. In arthritic hip patients osteophytes are often seen on both femoral head and acetabulum. Especially on femoral head, osteophytes are often seen at posterior side and its surface creates smooth round contour that assumes new joint surface. (Fig. 1). We can imagine new femoral head center tracing that new joint surface. OBJECTIVES. In the present study, the posterior osteophytes are compared in osteoarthritic patients and other patients. MATERIALS & METHODS. Anteversion and new anteversion which was reduced by osteophyte formation were assessed in 28 hip CAT scans, (22 arthritic hips, 6 avascular necrotic hips). RESULTS. Only in arthritic patients, osteophytes on posterior side were observed. The anteversion was 33.7+/− 13.0 degree in arthritic patients, which was reduce to 29.7+/−13.1 degree. The mean difference was 4.0+/−4.7 degree reduction. In AVN patients the mean anteversion was 21.4 +/− 9.40 in AVN patients. No reduction was observed in AVN patients. DISCUSSION. Osteophytes are often created to make the biomechanical situation better. This phenomenon is possiblly explained that those posterior osteophytes have been formed for proper reduction of excessive anteversion

Introduction. Up to 60% of total hip arthroplasties (THA) in Asian populations arise from avascular necrosis (AVN), a bone disease that can lead to femoral head collapse. Current diagnostic methods to classify AVN have poor reproducibility and are not reliable in assessing the fracture risk. Femoral heads with an immediate fracture risk should be treated with a THA, conservative treatments are only successful in some cases and cause unnecessary patient suffering if used inappropriately. There is potential to improve the assessment of the fracture risk by using a combination of density-calibrated computed tomographic (QCT) imaging and engineering beam theory. The aim of this study was to validate the novel fracture prediction method against in-vitro compression tests on a series of six human femur specimens. Methods. Six femoral heads from six subjects were tested, a subset (n=3) included a hole drilled into the subchondral area of the femoral head via the femoral neck (University of Leeds, ethical approval MEEC13-002). The simulated lesions provided a method to validate the fracture prediction model with respect of AVN. The femoral heads were then modelled by a beam loaded with a single joint contact load. Material properties were assigned to the beam model from QCT-scans by using a density-modulus relationship. The maximum joint loading at which each bone cross-section was likely to fracture was calculated using a strain based failure criterion. Based on the predicted fracture loads, all six femoral heads (validation set) were classified into two groups, high fracture risk and low fracture risk (Figure 1). Beam theory did not allow for an accurate fracture load to be found because of the geometry of the femoral head. Therefore the predicted fracture loads of each of the six femoral heads was compared to the mean fracture load from twelve previously analysed human femoral heads (reference set) without lesions. The six cemented femurs were compression tested until failure. The subjects with a higher fracture risk were identified using both the experimental and beam tool outputs. Results. The computational tool correctly identified all femoral head samples which fractured at a significantly low load in-vitro (Figure 2). Both samples with a low experimental fracture load had an induced lesion in the subchondral area (Figure 3). Discussion. This study confirmed findings of a previous verification study on a disease models made from porcine femoral heads (Preutenborbeck et al. I-CORS2016). It demonstrated that fracture prediction based on beam theory is a viable tool to predict fracture. The tests confirmed that samples with a lesion in the weight bearing area were more likely to fracture at a low load however not all samples with a lesion fractured with a low load experimentally, indicating that a lesion alone is not a sufficient factor to predict fracture. The developed tool takes both structural and material properties into account when predicting the fracture risk. Therefore it might be superior to current diagnostic methods in this respect and it has the added advantage of being largely automated and therefore removing the majority of user bias. For any figures or tables, please contact the authors directly

Anatomic reduction (subcapital re-alignment osteotomy) via surgical hip dislocation – increasingly popular. While the reported AVN rates are very low, experiences seem to differ greatly between centres. We present our early experience with the first 29 primary cases and a modified fixation technique. We modified the fixation from threaded Steinman pins to cannulated 6.5mm fully-threaded screws: retrograde guidewire placement before reduction of the head ensured an even spread in the femoral neck and head. The mean PSA (posterior slip angle) at presentation (between 12/2008 and 01/2011) was overall 68° (45–90°). 59% (17/29) were stable slips (mean PSA 68°), and 41% (12/29) were unstable slips unable to mobilise (mean PSA 67°). The vascularity of the femoral head was assessed postoperatively with a bone scan including tomography. The slip angle was corrected to a mean PSA of 5.8° (7° anteversion to 25° PSA). We encountered no complications related to our modified fixation technique. All cases with a well vascularised femoral head on the post-operative bone scan (15/17 stable slips and 8/12 unstable slips) healed with excellent short term results. Both stable slips with decreased vascularity on bone scan (2/17, 12%) had been longstanding severe slips with retrospectively suspected partial closure of the physis, which has been described as a factor for increased risk of avascular necrosis (AVN). One of these cases was complicated by a posterior redislocation due to acetabular deficiency. In the unstable group, 4/12 cases (33%) had avascular heads intra-operatively and cold postoperative bone scans, 3 have progressed to AVN and collapse. Anatomic reduction while sparing the blood supply of the femoral head is a promising concept with excellent short term results in most stable and many unstable SCFE cases. Extra vigilance for closed/closing physes in longstanding severe cases seems advisable. Regardless of treatment, some unstable cases inevitably go on to AVN

Metal-on-metal hip resurfacing prostheses are a relatively recent intervention for relieving the symptoms of common musculoskeletal diseases such as osteoarthritis. While some short term clinical studies have offered positive results, in a minority of cases there is a recognised issue of femoral fracture, which commonly occurs in the first few months following the operation. This problem has been explained by a surgeon's learning curve and notching of the femur but, to date, studies of explanted early fracture components have been limited. Tribological analysis was carried out on fourteen retrieved femoral components of which twelve were revised after femoral fracture and two for avascular necrosis (AVN). Eight samples were Durom (Zimmer, Indiana, USA) devices and six were Articular Surface Replacements (ASR, DePuy, Leeds, United Kingdom). One AVN retrieval was a Durom, the other an ASR. The mean time to fracture was 3.4 months. The AVNs were retrieved after 16 months (Durom) and 38 months (ASR). Volumetric wear rates were determined using a Mitutoyo Legex 322 co-ordinate measuring machine (scanning accuracy within 1 micron) and a bespoke computer program. The method was validated against gravimetric calculations for volumetric wear using a sample femoral head that was artificially worn in vitro. At 5mm. 3. , 10mm. 3. , and 15mm. 3. of material removal, the method was accurate to within 0.5mm. 3. Surface roughness data was collected using a Zygo NewView500 interferometer (resolution 1nm). Mean wear rates of 17.74mm. 3. /year were measured from the fracture components. Wear rates for the AVN retrievals were 0.43mm. 3. /year and 3.45mm. 3. /year. Mean roughness values of the fracture retrievals (PV = 0.754, RMS = 0.027) were similar to the AVNs (PV = 0.621, RMS = 0.030), though the AVNs had been in vivo for significantly longer. Theoretical lubrication calculations were carried out which found that in both AVN retrievals and in seven of the twelve cases of femoral fracture the roughening was sufficient to change the lubrication regime from fluid film to mixed. Three of these surfaces were bordering on the boundary lubrication regime. The results show that even before the femoral fracture, wear rates and roughness values were high and the implants were performing poorly

Introduction. We present a single surgeon series of 20 modified Dunn osteotomies without surgical dislocation of the femoral head for slipped upper femoral epiphysis (SUFE). Method. All patients from 2007 to 2011 who had a Dunn osteotomy for SUFE had their notes reviewed and we obtained an updated Non Arthritic Hip Score. Results. 20 patients were identified, of which 5 were female, with a combined average age of 14. The average duration of symptoms prior to the procedure was 10.2 weeks (range, 4–78). Classifications divided the cases into 7 chronic slips, 7 acute-on-chronic, and 5 acute., and 7 of the cases were unstable slips with an average slip angle of 71 degrees (range 65–85). All slips were grade 3. Average follow up was 26.2 months (range, 2–62). 3 developed avasular necrosis (2 unstable, 1 stable) and 2 patients had symptomatic leg length discrepancy. Preoperative MRI scans were performed in 4 patients and showed vascular compromise, but this did not always correlate with intraoperative findings of avascularity when the head was drilled. The average Nonarthritic hip score was 71.6 (range, 60–80). Summary. Dunn osteotomies are safe in patients with chronic slips, and have a low incidence of AVN. Overall function was good, even in those patients with segmental AVN scoring highly on their hip scores. Keeping the ligamentum teres intact and not dislocating the femoral head may improve vascularity of the head. Vascularity may also be assessed by preoperative MRI scans, although radiological suggestion of an avascular head which contradicted clinical findings and postoperative outcome may be due to transient vessel spasm