A tantalum AVN implant was used in sixteen patients with advanced AVN (Grade 3/4). No reports have been published of use of this implant in advanced disease. Outcomes included radiological, SF36, Harris hip score and secondary surgeries. HHS improved from fifty-two to seventy. SF36 scores approached controls. At over one year average follow-up five patients are revised to THA, however, all hips except one have at least minor pain. Revisions occurred in older patients or those with 100% head involvement. In younger patients, with up to 50% head involvement, this technique seems to be a viable option for advanced AVN. Evaluation of tantalum AVN implants in patients with advanced AVN. In younger patients, with up to 50% hip head involvement, this technique seems to be a viable option for advanced AVN. Revisions in general are in older patients or those with 100% head involvement. Most treatment options have had poor outcomes with advanced AVN. Surgeons generally perform THA or core decompression in these cases. Market pressure for a non-vascularized option to fill the channel after decompression has resulted in new implants. A tantalum device has been designed to fill the post-core decompression channel to allow subchondral support. This is a minimally invasive procedure with theoretically low morbidity. The average orthopedic surgeon would have no difficulty in the use of this implant. HHS improved from fifty-two to seventy. SF36 scores were below age-matched controls. At over one-year average follow-up five patients are revised to THA, however, all hips except one have at least minor pain. Revisions in general are in older patients or those with 100% involvement. In younger patients, with up to 50% head involvement, this technique seems to be a viable option. This device was used in a prospective cohort of sixteen patients with advanced AVN (Grade 3/4) with femoral head fracture/collapse. Operative technique including reduction of the fracture allows for improved results. Outcomes included radiological parameters (advancing disease, placement, ingrowth), SF36, Harris hip score and secondary surgeries

The authors are not aware of any research comparing computed tomography (CT) and avascular necrosis (AVN) of the scaphoid bone. The primary aim of our study was to investigate the use of longitudinal CT in predicting AVN of the proximal pole of the scaphoid, and subsequent fracture nonunion following internal fixation. Thirty-two patients operated on by the senior author for scaphoid fracture were included. Preoperative CT scans were independently assessed for deformity, comminution, fracture position, proximal pole sclerosis, and bridging trabeculae. Intra-operative biopsy of the proximal pole was assessed independently by a blinded musculoskeletal histologist. AVN was determined by histology of a proximal pole biopsy, using the criteria described by Ficat. Post-operative CT scan was utilised to determine fracture union. Preoperative CT features which significantly correlated with AVN were, increased radiodensity of the proximal pole, the absence of any bridging trabeculae comminution, dorsal cortical angle, proximal fracture and age less than 20. Features predictive of subsequent nonunion were fractures of the proximal, increased radiodensity of the proximal pole, and AVN. Preoperative CT scan findings are significantly correlated with histologically confirmed AVN and fracture union. Preoperative longitudinal CT scan is of significant prognostic value and should be considered to assist in predicting outcome and assessing treatment options

Introduction: The results of 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 is a single-surgeon consecutive series of BHRs with a minimum follow-up of 5 years. Fifty six patients with Ficat-Arlet grade III or IV femoral head AVN and treated with BHRs at a mean age of 44.2 years (range 19 to 67.7 years) were followed-up for 5 to 9.2 years (mean 6.8 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 four failures in this cohort giving a failure rate of 7% and a cumulative survivorship of 92.9% at 9 years (figure). 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 (92.9%) compared to those with other diagnoses make AVN a relative contraindication to this procedure

Introduction: Avascular necrosis (AVN) of the femoral head (FH) is a painful disorder of the hip that leads to hip collapse. The pathology of AVN involves ischemic events leading to the death of bone. Several biological substances participate in the balance between osteoclasts and osteoblasts, like osteoprotegerin, RANK and RANKL. The expression of these genes affects the maturation and function of osteoblasts and osteoclasts and determines the rate of bone remodeling. In this study, we investigate the expression of OPG, RANK and RANKL in osteonecrotic FHs derived from 44 patients with AVN. Methods and Materials: RNA and proteins were isolated from both necrotic and normal site of FHs of 44 patients diagnosed with AVN. Quantitative RT-PCR was performed for OPG, RANKL and RANK molecules by using the Light Cycler FastStart DNA Master Hybridization Probes kit (Roche). Western Blotting: 22 bone tissues were run on 4–12% NuPAGE gel (Invitrogen). Anti-OPG, anti-RANKL and anti-actin antibodies were used and membranes were immersed in ECL. Results: Quantitative RT-PCR: The mRNA levels of OPG were higher in the necrotic (median: 5.25) than the normal site (median: 4.19) of the FHs and their difference was statistically significant (p< 0.05). The expression of RANK and RANKL was significantly lower than that of OPG following a similar pattern between the necrotic and normal site. The mRNA values of RANK and RANKL were higher in the necrotic sites [necrotic median: 1.0/normal median: 0.85, necrotic median: 0.8, normal median: 0.3, respectively] than the normal, although they were not statistically significant. Western Blotting analysis: Normal sites from all FHs showed comparable OPG protein levels (median: 0.57) which were similar to those of normal (median: 0.63). Similar pattern to that of OPG was observed also for RANKL protein expression, where the median value for RANKL/F-actin ratio was 0.49 and 0.5 in normal and necrotic sites of FHs, respectively. Discussion: OPG, RANK and RANKL are key genes for maintaining the balance between osteoblasts and osteoclasts. Our results show marked differences in the expression of OPG between the necrotic and the normal sites of the FHs; however, mRNA levels of RANKL varied insignificantly between normal and necrotic part of FH while mRNA levels of RANK gene remain similar in both sides of FHs. In contrast, the production of OPG and RANKL at the protein level showed no remarkable divergence. This indicates that the expression and production pattern of RANK may play the key role in the maintenance of the balance between osteoblasts and osteoclasts in AVN

Ischemic necrosis of the femoral head occurring after the treatment of congenital dysplasia of the hip can negatively affect the long-term prognosis of the involved hip. The purpose of the study was to evaluate a number of clinical and radiological risk factors for AVN after non-operative treatment of DDH. Clinical data and radiographs of 77 patients with103 abnormal hips treated because of developmental dysplasia of the hip by closed reduction followed by cast immobilization were reviewed retrospectively. The average age of patients at the time of reduction was 16 months (ranged, 4 to 28) and the average final follow up was 22,4 years (ranged from 13 to 47 years). Kalamchi and MacEwen classification system was used for evaluation of the AVN. Avascular necrosis was found in 35,9% of the treated hips. We established the influence of several radiological and clinical data on the incidence and severity of AVN. Conclusion: In our analysis the degree of initial dislocation according to Tönnis classification is an important risk factor for AVN. Age at the onset of treatment, presence and size of ossific nucleus, the use and period of preliminary traction, previous treatment with Frejka pillow or Pavlik splint, sex and side were not associated with the incidence and severity of ischemic necrosis. The results have been analysed statistically

Avascular necrosis is poorly understood. The etiological factors have not been fully delineated. This disease process had a huge cost impact on the health system due to surgical treatment. Patients with avascular necrosis seen at a single institution underwent DNA extraction and analysis, coagulation-related analysis and buccal smears with DNA analysis. In this patient group 60% tested positive for at least one thrombophilic or hypofibrinolysis factor. We make recommendations depending on the defect in the cascade, allowing for potential non-surgical management of osteonecrosis in patients undergoing therapy with known antagonistic medications (i.e. corticosteroids). The etiology and pathogenesis of nontraumatic AVN need to be better elucidated. Our study identifies the potential association of thrombophilic and hypofibrinolytic factors and osteonecrosis of the hip, particularly genetic markers as identified through DNA markers. The significance of this study:. Osteonecrosis is a devastating musculoskeletal condition;. Tends to occur in young people;. Treatments are suboptimal mostly palliative and not curative;. currently unable to identify persons at risk for AVN;. cannot reverse the process once AVN has developed. 60% of patients had at least one tested thrombophilic or hypofibrinolysis factor positive. Most patients never had a thrombotic event. Genetic screening, multiple hematological paramteres were tested on patients with avascular necrosis. hypercoagulability plays a role in the development of AVN of the hip, mainly at the microvascular level;. an impairment at the level of the fibrinolytic system through high PAI-1 levels is a potential mechanism responsible for the development of AVN;. a genetic predisposition is implicated, at least in part, in the development of AVN of the hip. most patietns had a multifactorial problem and genetic screening and blood testing will lead to recommended therapy (medical) for those patients at risk

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

We investigated the incidence and risk factors for the development of avascular necrosis (AVN) of the femoral head in the course of treatment of children with cerebral palsy (CP) and dislocation of the hip. All underwent open reduction, proximal femoral and Dega pelvic osteotomy. The inclusion criteria were: a predominantly spastic form of CP, dislocation of the hip (migration percentage, MP > 80%), Gross Motor Function Classification System, (GMFCS) grade IV to V, a primary surgical procedure and follow-up of > one year. There were 81 consecutive children (40 girls and 41 boys) in the study. Their mean age was nine years (3.5 to 13.8) and mean follow-up was 5.5 years (1.6 to 15.1). Radiological evaluation included measurement of the MP, the acetabular index (AI), the epiphyseal shaft angle (ESA) and the pelvic femoral angle (PFA). The presence and grade of AVN were assessed radiologically according to the Kruczynski classification. Signs of AVN (grades I to V) were seen in 79 hips (68.7%). A total of 23 hips (18%) were classified between grades III and V. Although open reduction of the hip combined with femoral and Dega osteotomy is an effective form of treatment for children with CP and dislocation of the hip, there were signs of avascular necrosis in about two-thirds of the children. There was a strong correlation between post-operative pain and the severity of the grade of AVN. Cite this article: Bone Joint J 2015;97-B:270–6

Numerous procedures have been reported for the hallux valgus correction of the great toe. Scarf osteotomy is a versatile osteotomy to correct varying degrees of mild to moderate hallux valgus deformity. It can also be used for lengthening of the 1st ray as a revision procedure to treat metatarsalgia in patients who had previous shortening osteotomy. We wish to report a patient who had lengthening SCARF osteotomy for the metatarsalgia following previous hallux valgus correction and developed arthritis of the 1st MTPJ in a short term which required fusion. A 49 year old female patient was seen with pain and tenderness over the heads of the 2nd and3rd metatarsal of the right foot. She had hallux valgus correction 10years ago with a shortening osteotomy of the 1st metatarsal. She developed metatarsalgia which failed to conservative management. She had a lengthening SCARF osteotomy for the metatarsalgia in 2004. She had good symptomatic relief for two years and then started having pain over the 1st MTPJ. On examination she had limited movements of the 1st MTPJ and tenderness over the dorsolateral aspects of the 1st MTPJ suggestive of arthritis. Radiographs of the foot showed healed osteotomy with no evidence of AVN of the 1st MT head but features suggestive of osteoarthritis. She had fusion of the 1st MTPJ performed in 2008 for the arthritis following which symptoms resolved. This case highlights that arthritis of the 1st MTPJ can occur in the absence of an AVN of the metatarsal head and patients need to be warned of this potential complaining when having the lengthening SCARF osteotomy for metatarsalgia following a previous shortening osteotomy of the 1st ray

Purpose: Glucocorticoids (GCs) are widely prescribed drugs in a large variety of diseases. Their use are strongly influenced by their associated negative side effects. Bone-related effects are mainly osteoporosis and osteonecrosis (ON). Despite the strong link between GCs and ON, the pathogenic mechanisms by which GCs cause ON are still unclear. Cumulative evidence shows that dysfunction or activation of endothelial cells (ECs) play an important role in ON.

Method: In this study, we investigated the influence of dexamethasone (Dex) on the Tumor Necrosis Factor-alpha [TNF-alpha] or Lipopolysaccharide [LPS] or Thrombin [IIa] -stimulated Human Umbilical Vein Endothelial Cells (HUVEC). We examined the molecular expression of 9 candidate genes (E-selectin [E-Sel], Intracellular adhesion molecule-1 [ICAM-1], Plasminogen activator inhibitor-1 [PAI-1], Tissue Factor [TF], Tissue plasminogen activator [t-PA], Urokinase plasminogen activator [u-PA], Vascular adhesion molecule-1 [VCAM-1], Von Willebrand Factor [vWF] and Thrombomodulin [THBD]) by real-time PCR. Live cell number of HUVEC under exposure to Dex was also assayed by viability test. All experiments were performed in triplicates and Standard error of the mean (SEM) was obtained.

Results: We showed that Dex alone significantly induced the expression of E-Sel, ICAM-1, TF, VCAM-1 and VWF while downregulating THBD and U-PA expression. Our results also showed a significant priming effect of Dex on E-Sel and TF inflammatory-mediated induction by TNF-alpha and LPS respectively. Comparable results were obtained from Northern Blot analysis; results from FACS analysis and Functional assays will be presented at the meeting.

Conclusion: Our observations suggest a procoagulant activity of Dex on HUVEC. We also observed a priming activity of Dex on E-Sel and TF inflammatory-mediated induction. These results suggest a potential endothelial cell activation mechanism and subsequent microvascular thrombosis in glucocorticoid-induced ON.

Aims. The most important complication of treatment of developmental dysplasia of the hip (DDH) is avascular necrosis (AVN) of the femoral head, which can result in proximal femoral growth disturbances leading to pain, dysfunction, and eventually to early onset osteoarthritis. In this study, we aimed to identify morphological variants in hip joint development that are predictive of a poor outcome. Methods. We retrospectively reviewed all patients who developed AVN after DDH treatment, either by closed and/or open reduction, at a single institution between 1984 and 2007 with a minimal follow-up of eight years. Standard pelvis radiographs obtained at ages one, two, three, five, and eight years, and at latest follow-up were retrieved. The Bucholz-Ogden classification was used to determine the type of AVN on all radiographs. Poor outcome was defined by Severin classification grade 3 or above on the latest follow-up radiographs and/or the need for secondary surgery. With statistical shape modelling, we identified the different shape variants of the hip at each age. Logistic regression analysis was used to associate the different modes or shape variants with poor outcome. Results. In all, 135 patients with AVN were identified, with a minimum of eight years of follow-up. Mean age at time of surgery was 7.0 months (SD 0.45), and mean follow-up was 13.3 years (SD 3.7). Overall, 46% had AVN type 1 while 54% type 2 or higher. More than half of the patients (52.6%) had a poor outcome. We found 11 shape variants that were significantly associated with a poor outcome. These shape variants were predominantly linked to AVN type 2 or higher. Conclusion. Specific morphological characteristics on pelvis radiographs of AVN hips were predictive for poor outcome, at a very young age. There was an overall stronger association to Bucholz-Ogden types 2-3-4 with the exception of two modes at age two and five years, linked to AVN type 1. Cite this article: Bone Joint J 2021;103-B(5):999–1004

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

Aims. To determine the likelihood of achieving a successful closed reduction (CR) of a dislocated hip in developmental dysplasia of the hip (DDH) after failed Pavlik harness treatment We report the rate of avascular necrosis (AVN) and the need for further surgical procedures. Methods. Data was obtained from the Northern Ireland DDH database. All children who underwent an attempted closed reduction between 2011 and 2016 were identified. Children with a dislocated hip that failed Pavlik harness treatment were included in the study. Successful closed reduction was defined as a hip that reduced in theatre and remained reduced. Most recent imaging was assessed for the presence of AVN using the Kalamchi and MacEwen classification. Results. There were 644 dislocated hips in 543 patients initially treated in Pavlik harness. In all, 67 hips failed Pavlik harness treatment and proceeded to arthrogram (CR) under general anaesthetic at an average age of 180 days. The number of hips that were deemed reduced in theatre was 46 of the 67 (69%). A total of 11 hips re-dislocated and underwent open reduction, giving a true successful CR rate of 52%. For the total cohort of 67 hips that went to theatre for arthrogram and attempted CR, five (7%) developed clinically significant AVN at an average follow-up of four years and one month, while none of the 35 hips whose reduction was truly successful developed clinically significant AVN. Conclusion. The likelihood of a successful closed reduction of a dislocated hip in the Northern Ireland population, which has failed Pavlik harness treatment, is 52% with a clinically significant AVN rate of 7%. As such, we continue to advocate closed reduction under general anaesthetic for the hip that has failed Pavlik harness. Cite this article: Bone Jt Open 2021;2(8):594–598

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

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

Aims. The aim of this study was to clarify the factors that predict the development of avascular necrosis (AVN) of the femoral head in children with a fracture of the femoral neck. Patients and Methods. We retrospectively reviewed 239 children with a mean age of 10.0 years (. sd. 3.9) who underwent surgical treatment for a femoral neck fracture. Risk factors were recorded, including age, sex, laterality, mechanism of injury, initial displacement, the type of fracture, the time to reduction, and the method and quality of reduction. AVN of the femoral head was assessed on radiographs. Logistic regression analysis was used to evaluate the independent risk factors for AVN. Chi-squared tests and Student’s t-tests were used for subgroup analyses to determine the risk factors for AVN. Results. We found that age (p = 0.006) and initial displacement (p = 0.001) were significant independent risk factors. Receiver operating characteristic (ROC) curve analysis indicated that 12 years of age was the cut-off for increasing the rate of AVN. Severe initial displacement (p = 0.021) and poor quality of reduction (p = 0.022) significantly increased the rate of AVN in patients aged 12 years or greater, while in those aged less than 12 years, the rate of AVN significantly increased only with initial displacement (p = 0.048). A poor reduction significantly increased the rate of AVN in patients treated by closed reduction (p = 0.026); screw and plate fixation was preferable to cannulated screw or Kirschner wire (K-wire) fixation for decreasing the rate of AVN in patients treated by open reduction (p = 0.034). Conclusion. The rate of AVN increases with age, especially in patients aged 12 years or greater, and with the severity of displacement. In patients treated by closed reduction, anatomical reduction helps to decrease the rate of AVN, while in those treated by open reduction, screw and plate fixation was preferable to fixation using cannulated screws or K-wires. Cite this article: Bone Joint J 2019;101-B:1160–1167

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

Aims. Brace treatment is the cornerstone of managing developmental dysplasia of the hip (DDH), yet there is a lack of evidence-based treatment protocols, which results in wide variations in practice. To resolve this, we have developed a comprehensive nonoperative treatment protocol conforming to published consensus principles, with well-defined a priori criteria for inclusion and successful treatment. Methods. This was a single-centre, prospective, longitudinal cohort study of a consecutive series of infants with ultrasound-confirmed DDH who underwent a comprehensive nonoperative brace management protocol in a unified multidisciplinary clinic between January 2012 and December 2016 with five-year follow-up radiographs. The radiological outcomes were acetabular index-lateral edge (AI-L), acetabular index-sourcil (AI-S), centre-edge angle (CEA), acetabular depth ratio (ADR), International Hip Dysplasia Institute (IHDI) grade, and evidence of avascular necrosis (AVN). At five years, each hip was classified as normal (< 1 SD), borderline dysplastic (1 to 2 SDs), or dysplastic (> 2 SDs) based on validated radiological norm-referenced values. Results. Of 993 infants assessed clinically and sonographically, 21% (212 infants, 354 abnormal hips) had DDH and were included. Of these, 95% (202 infants, 335 hips) successfully completed bracing, and 5% (ten infants, 19 hips) failed bracing due to irreducible hip(s). The success rate of bracing for unilateral dislocations was 88% (45/51 infants) and for bilateral dislocations 83% (20/24 infants). The femoral nerve palsy rate was 1% (2/212 infants). At five-year follow-up (mean 63 months (SD 5.9; 49 to 83)) the prevalence of residual dysplasia after successful brace treatment was 1.6% (5/312 hips). All hips were IHDI grade I and none had AVN. Four children (4/186; 2%) subsequently underwent surgery for residual dysplasia. Conclusion. Our comprehensive protocol for nonoperative treatment of infant DDH has shown high rates of success and extremely low rates of residual dysplasia at a mean age of five years. Cite this article: Bone Joint J 2023;105-B(8):935–942