Determination of rotation center and diameter of femoral heads using off-the-shelf augmented reality hardware for navigation.

In total hip arthroplasty (THA), determining the center of rotation (COR) and diameter of the hip joint (acetabulum and femoral head) is essential to restore patient biomechanics. This study investigates on-the-fly determination of hip COR and size, using off-the-shelf augmented reality (AR) hardware. An AR head-mounted device (HMD) was configured with inside-out infrared tracking enabling the determination of surface coordinates using a handheld stylus. Two investigators examined 10 prosthetic femoral heads and cups, and 10 human femurs. The HMD calculated the diameter and COR through sphere fitting. Results were compared to data obtained from either verified prosthetic geometry or post-hoc CT analysis. Repeated single-observer measurements showed a mean diameter error of 0.63 mm ± 0.48 mm for the prosthetic heads and 0.54 mm ± 0.39 mm for the cups. Inter-observer comparison yielded mean diameter errors of 0.28 mm ± 0.71 mm and 1.82 mm ± 1.42 mm for the heads and cups, respectively. Cadaver testing found a mean COR error of 3.09 mm ± 1.18 mm and a diameter error of 1.10 mm ± 0.90 mm. Intra- and inter-observer reliability averaged below 2 mm. AR-based surface mapping using HMD proved accurate and reliable in determining the diameter of THA components with promise in identifying COR and diameter of osteoarthritic femoral heads.

Changes in nail position and antirotation blade angles on the risk of femoral head varus in PFNA fixed patients: a clinical review and comprehensive biomechanical research.

BACKGROUND: Femoral head varus triggers poor clinical prognosis in intertrochanteric fracture patients with proximal femoral nail antirotation (PFNA) fixation. Studies present that changes in nail position and screw insertion angles will affect fixation stability, but the biomechanical significance of these factors on the risk of femoral head varus has yet to be identified in PFNA fixed patients. METHODS: Clinical data in PFNA fixed intertrochanteric fracture patients have been reviewed, the relative position of intermedullary nail has been judged in the instant postoperative lateral radiography. Regression analyses have been performed to identify the effect of this factor on femoral head varus. Corresponding biomechanical mechanism has been identified by numerical mechanical simulations. RESULTS: A clinical review revealed that ventral side nail insertion can trigger higher risk of femoral head varus, corresponding numerical mechanical simulations also recorded poor fixation stability in models with ventral side nail insertion, and changes in the trajectory of anti-rotation blade will not obviously affect this tendency. CONCLUSIONS: Ventral side insertion of intramedullary nail can trigger higher risk of femoral head varus in PFNA fixed patients by deteriorating the instant postoperative biomechanical environment, and changes in blade trajectory cannot change this tendency biomechanically. Therefore, this nail position should be adjusted to optimize patients' prognosis.

Comparison of SHD-IBG and PVIBGT in ONFH including mechanical and pathological analysis of failure cases.

Currently, there is a lack of relevant research on the efficacy difference between SHD combined with IBG and PVIBGT in the treatment of osteonecrosis of the femoral head(ONFH). Firstly, this study intends to compare the effectiveness of surgical hip dislocation combined with impacting bone grafts (SHD-IBG) and pedicled vascularised iliac bone graft transfer (PVIBGT) in treating ONFH. And the study investigates patients who suffered from hip preservation failures from both groups to better comprehend failure reasons. 30 patients (34 hips) with ARCO stage IIIA femoral head necrosis were selected between January 2012 and July 2022. They were divided into group A(SHD-IBG) and group B (PVIBGT) according to different surgical methods. Firstly, compared the 1-year effect between SHD-IBG and PVIBGT at 1 year postoperatively; Secondly, assessed the medium and long-term efficacy of SHD-IBG hip preservation treatment; Lastly, based on study of the femoral head removed from patients with hip preservation failure in the two groups, the reasons for the failure of hip preservation were comprehensively analyzed in the two groups. Group A: 11 males (13 hips), 4 females (4 hips);Group B: 9 males (11 hips), 6 females (6 hips).Firstly, the average Harris scores of the two groups at 1 year after surgery: preoperative: 70.7, 1 year after surgery: 78.9 in group A; preoperative: 69.5, 1 year after surgery: 81.5 in group B. The differences were statistically significant (P < 0.05).Compared to the preoperative period, quantitative analysis by DCE-MRI showed an increase in perfusion in the necroticarea and an improvement in hyperperfusion in the repair-responsive area one year after the surgery. Secondly, in group A, the hip preservation rate was 88.2% at 2.5-11 (average of 77 months) years of follow-up, and the mean Harris score at the last follow-up was 73.2.Semi-quantitative analysis of postoperative DCE-MRI showed that the perfusion curves of necrotic and repaired areas were similar to those of the normal area. This suggests the instability within the femoral head had been effectively improved, and the perfusion had partially recovered. Thirdly, according to Micro-CT and pathologica studies of patients with hip preservation failure in these two groups, all these patients' femoral head was significantly collapsed and deformed. Their trabeculae was thin and partially disorganized, with fractures in the subchondral bone and separation of the cartilage from the subchondral bone. The necrotic areas had sparse trabeculae, disorganized arrangement, loss of continuity, and disappearance of cells in the trabecular traps. The necrotic area was covered with fibrous tissue, and partial restoration was observed in the repair area. Mechanical finite element analysis showed that the maximum equivalent force was observed in the weight- bearing area and the cortical bone surrounding the shaft of femurand. The result of DCE-MRI showed that the repair reaction area exhibited abnormal hyperperfusion. In this study, the efficacy of SHD-IBG and PVIBGT was compared at 1 year after operation, and the long-term follow-up of SHD-IBG was 2.5-11 (mean 77 months) years, combined with DCE-MRI results, we found that the short-term effect of PVIBGT was more significant than that of SHD-IBG. SHD-IBG can achieve satisfactory hip preservation in the medium and long term follow-up.

Risk factors for avascular necrosis of the femoral head after developmental hip dislocation reduction surgery and construction of Nomogram prediction model.

BACKGROUND: To analyze the risk factors for the development of avascular necrosis (AVN) of the femoral head after reduction surgery in children with developmental hip dysplasia (DDH), and to establish a prediction nomogram. METHODS: The clinical data of 134 children with DDH (169 hips) treated with closure reduction or open reduction from December 2016 to December 2019 were retrospectively analyzed. Independent risk factors for AVN after DDH reduction being combined with cast external immobilization were determined by univariate analysis and multivariate logistic regression and used to generate nomograms predicting the occurrence of AVN. RESULTS: A total of 169 hip joints in 134 children met the inclusion criteria, with a mean age at surgery of 10.7 ± 4.56 months (range: 4-22 months) and a mean follow-up duration of 38.32 ± 27.00 months (range: 12-94 months). AVN developed in 42 hip joints (24.9%); univariate analysis showed that the International Hip Dysplasia Institute (IHDI) grade, preoperative development of the femoral head ossification nucleus, cartilage acetabular index, femoral head to acetabular Y-shaped cartilage distance, residual acetabular dysplasia, acetabular abduction angle exceeding 60°, and the final follow-up acetabular index (AI) were associated with the development of AVN (P < 0.05). Multivariate logistic regression analysis showed that the preoperative IHDI grade, development of the femoral head ossification nucleus, acetabular abduction angle exceeding 60°, and the final follow-up AI were independent risk factors for AVN development (P < 0.05). Internal validation of the Nomogram prediction model showed a consistency index of 0.833. CONCLUSION: Preoperative IHDI grade, preoperative development of the femoral head ossification nucleus, final AI, and acetabular abduction angle exceeding 60° are risk factors for AVN development. This study successfully constructed a Nomogram prediction model for AVN after casting surgery for DDH that can predict the occurrence of AVN after casting surgery for DDH.

Outcomes of Hybrid Total Hip Arthroplasty for Subchondral Insufficiency Fracture of the Femoral Head.

Background: The purpose of this study was to evaluate functional outcomes, radiologic results, and complications after hybrid total hip arthroplasty (THA) in patients with subchondral insufficiency fractures (SIFs) of the femoral head. Methods: From June 2009 to December 2020, among 985 patients who underwent hybrid THA at our hospital, 19 patients diagnosed with SIF through a retrospective chart review were included. Those under 50 years of age, with radiographic findings of osteonecrosis on the contralateral side of surgery, a history of organ transplantation, and alcohol abuse, were excluded. Functional evaluation was performed using a modified Harris Hip Score (HHS). After surgery, inclination and anteversion of the acetabular cup and version of the femoral system were measured using postoperative x-ray. The outpatient follow-up was performed at 6 weeks, 3 months, 9 months, and 12 months after surgery and every year thereafter. Complications including dislocation, implant loosening, stem subsidence, and periprosthetic infection were observed on follow-up radiographs. Results: The average follow-up time was 29.3 ± 9.1 months (range, 24-64 months) with no loss to follow-up. The mean modified HHS was 83.4 ± 9.6 (range, 65-100) at the last outpatient clinic follow-up. The average inclination of the acetabular cup was 41.9° ± 3.4° (range, 37°-48°), and the anteversion was 27.5° ± 6.7° (range, 18°-39°). The version of the femoral stem was 19° ± 5.7° (range, 12°-29°). There was no case of intraoperative fracture. There were no cases of dislocation, loosening of the cup, subsidence of the femoral stem, intraoperative or periprosthetic fracture, or periprosthetic infection on the follow-up radiographs. Conclusions: In our study, hybrid THA showed favorable outcomes in patients diagnosed with SIF, and there were no further special considerations as for THA performed due to other diseases or fractures.

Extending the intermedullary nail will not reduce the potential risk of femoral head varus in PFNA patients biomechanically: a clinical review and corresponding numerical simulation.

Femoral head varus is an important complication in intertrochanteric fracture patients treated with proximal femoral nail anti-rotation (PFNA) fixation. Theoretically, extending the length of the intramedullary nail could optimize fixation stability by lengthening the force arm. However, whether extending the nail length can optimize patient prognosis is unclear. In this study, a review of imaging data from intertrochanteric fracture patients with PFNA fixation was performed, and the length of the intramedullary nail in the femoral trunk and the distance between the lesser trochanter and the distal locking screw were measured. The femoral neck varus status was judged at the 6-month follow-up. The correlation coefficients between nail length and femoral neck varus angle were computed, and linear regression analysis was used to determine whether a change in nail length was an independent risk factor for femoral neck varus. Moreover, the biomechanical effects of different nail lengths on PFNA fixation stability and local stress distribution have also been verified by numerical mechanical simulations. Clinical review revealed that changes in nail length were not significantly correlated with femoral head varus and were also not an independent risk factor for this complication. In addition, only slight biomechanical changes can be observed in the numerical simulation results. Therefore, commonly used intramedullary nails should be able to meet the needs of PFNA-fixed patients, and additional procedures for longer nail insertion may be unnecessary.

Intraoperative live measurement of femoral head size for acetabular cup sizing: simple, accurate, and green!

PURPOSE: Templating is the first step in achieving a successful total hip arthroplasty. We hypothesize that native head size is highly correlated with implanted cup size. Therefore, the purpose of this study is to look for a correlation between sizes of the intra-operative measurement of the femoral head and the implanted cup. METHODS: This is a monocentric observational study conducted from December 2018 till January 2023. All patients admitted for a primary total hip arthroplasty were included and retrospectively reviewed. Intra-operative femoral head measurement, radiographic femoral head diameter, templated (planned) cup size, and definitive implanted cup size were recorded. RESULTS: The sample included 154 patients (85 female and 69 males) with a mean age of 66.2 ± 10.4 years. There were 157 THA cases; 82 on the right side and 75 on the left side. The native head size and acetate template on digital radiographs were the most significantly positively correlated with cup size (P < 0.0001) while the radiological head size was significantly negatively correlated with cup size (P = 0.009). The implanted cup was on average 2 ± 2 mm bigger than the native head size measured intra-operatively. CONCLUSION: The native femoral head diameter measured intra-operatively is a simple and reliable tool to help the surgeons choose the proper size of the acetabular cup, preventing complications during surgery hence optimizing results post operatively. This technique would contribute to a more ecofriendly orthopaedic reconstructive surgery.

Hip Preservation and Capanna Reconstruction for Pediatric Proximal Femur Ewing Sarcoma: A Report of 2 Cases.

CASE: This is a first report describing preservation of the femoral head by transcervical resection of proximal femoral Ewing sarcoma in 2 pediatric patients. A unique Capanna reconstruction supported joint salvage. At 1 year, Pediatric Outcomes Data Collection Instrument and Pediatric Toronto Extremity Salvage Score outcomes were excellent. Surveillance magnetic resonance imaging was without evidence of recurrence or impaired perfusion to the femoral head. CONCLUSION: We demonstrate the feasibility of hip joint preservation and maintenance of femoral head viability after transcervical resection of pediatric proximal femur bone sarcomas while preserving the medial circumflex femoral artery. This technique may be a preferred option over joint sacrifice and endoprosthetic replacement in young patients when tumor margins permit.

The force at the implant cannot be assessed by the mallet force-Unless supported by a model.

The implantation of uncemented prostheses requires the application of sufficient forces to achieve a press-fit of the implant in the bone. Excessive forces have to be omitted to limit bone damage. Force measurements along the force transmission path between mallet and implant are frequently used to investigate this trade-off. Placing a load cell at a position of interest (PoI), which might be the implant bone interface or the head taper junction, is technically challenging or even impossible so that nearby positions are chosen. Thus, a certain inertia and stiffness remain between the PoI and the sensor, and consequently the measured dynamic forces differ from those at the PoI. This experimental and numerical study aimed to investigate the amount of force reduction along the transmission path while joining femoral heads to stem tapers. Forces were measured in vitro at the tip of the mallet, directly above the polymer tip of the impactor and below the stem taper. Springs and masses were used to represent the responding tissue of a patient. A semi-empirical numerical model of the force transmission path was developed and validated in order to simulate a larger range of responding tissue properties than experimentally possible and to investigate the influence of different surgical instruments. A distinct attenuation was observed since the peak forces at the impactor reached 35% of the applied peak forces and 21% at the stem taper, respectively. The force curves were replicated with a median root mean square error of 3.8% of the corresponding mallet blow for the impactor and 3.6% for the stem. The force measurement position and the used surgical instruments have a strong influence on the measured forces. Consequently, the exact measurement conditions with regard to sensor positioning and used surgical instruments have to be specified and hence only studies with similar setups should be compared to avoid misestimation of the forces at the PoI. The proposed dynamic numerical model is a useful tool to calculate the impact of the chosen or changed mechanical parameters prior to executing experiments and also to extrapolate the effect of changing the applied forces to the resulting forces at the PoI.

Ganz femoral head reduction associated with coverage and containment procedures improve radiological and functional outcomes in Perthes' disease.

Aims: Ganz's studies made it possible to address joint deformities on both the femoral and acetabular side brought about by Perthes' disease. Femoral head reduction osteotomy (FHRO) was developed to improve joint congruency, along with periacetabular osteotomy (PAO), which may enhance coverage and containment. The purpose of this study is to show the clinical and morphological outcomes of the technique and the use of an implemented planning approach. Methods: From September 2015 to December 2021, 13 FHROs were performed on 11 patients for Perthes' disease in two centres. Of these, 11 hips had an associated PAO. A specific CT- and MRI-based protocol for virtual simulation of the corrections was developed. Outcomes were assessed with radiological parameters (sphericity index, extrusion index, integrity of the Shenton's line, lateral centre-edge angle (LCEA), Tönnis angle), and clinical parameters (range of motion, visual analogue scale (VAS) for pain, Merle d'Aubigné-Postel score, modified Harris Hip Score (mHHS), and EuroQol five-dimension five-level health questionnaire (EQ-5D-5L)). Early and late complications were reported. Results: The mean follow-up was 39.7 months (standard deviation (SD) 26.4). The mean age at surgery was 11.4 years (SD 1.6). No major complications were recorded. One patient required a total hip arthroplasty. Mean femoral head sphericity increased from 46.8% (SD 9.34%) to 70.2% (SD 15.44; p < 0.001); mean LCEA from 19.2° (SD 9.03°) to 44° (SD 10.27°; p < 0.001); mean extrusion index from 37.8 (SD 8.70) to 7.5 (SD 9.28; p < 0.001); and mean Tönnis angle from 16.5° (SD 12.35°) to 4.8° (SD 4.05°; p = 0.100). The mean VAS improved from 3.55 (SD 3.05) to 1.22 (1.72; p = 0.06); mean Merle d'Aubigné-Postel score from 14.55 (SD 1.74) to 16 (SD 1.6; p = 0.01); and mean mHHS from 60.6 (SD 18.06) to 81 (SD 6.63; p = 0.021). The EQ-5D-5L also showed significant improvements. Conclusion: FHRO associated with periacetabular procedures is a safe technique that showed improved functional, clinical, and morphological outcomes in Perthes' disease. The newly introduced simulation and planning algorithm may help to further refine the technique.

The influence of surgical technique guidance and surgeon's experience on the femoral head assembly in total hip arthroplasty.

INTRODUCTION: The importance of the assembly procedure on the taper connection strength is evident. However, existent surgical technique guides frequently lack comprehensive and precise instructions in this regard. The aim of our experimental study was to evaluate the influence of the surgical technique guide on the femoral head assembly procedure in surgeons with differing levels of experience in total hip arthroplasty. MATERIALS AND METHODS: Twenty-eight participants, divided into four groups based on their lifetime experience in total hip arthroplasty, conducted a femoral head assembly procedure in a simulated intraoperative environment before and after reviewing the surgical technique guide. Demographic information and the number of hammer blows were documented. Hammer velocity and impaction angle were recorded using an optical motion capturing system, while the impaction force was measured using a dynamic force sensor within the impactor. RESULTS: We observed a high variation in the number of hammer blows, maximum force, and impaction angle. Overall, the number of hammer blows decreased significantly from 3 to 2.2 after reviewing the surgical technique guide. The only significant intragroup difference in the number of hammer blows was observed in the group with no prior experience in total hip arthroplasty. No correlation was found between individual factors (age, weight, height) or experience and the measured parameters (velocity, maximum force and angle). CONCLUSIONS: The present study demonstrated a high variation in the parameters of the femoral head assembly procedure. Consideration of the surgical technique guide was found to be a limited factor among participants with varying levels of experience in total hip arthroplasty. These findings underline the importance of sufficient preoperative training, to standardize the assembly procedure, including impaction force, angle, and use of instruments.

Application direct anterior approach in pediatric femoral head and neck lesions.

BACKGROUND: Femoral neck is one of the high-risk areas for benign tumors and tumor-like lesions. Small range of lesions may also lead to pathological fracture, femoral head necrosis and other serious problems. PURPOSE: To investigate a new minimally invasive surgical approach to resect femoral head and neck lesions in children. PATIENTS AND METHODS: Retrospective study of 20 patients with femoral neck and femoral head lesions from February 2019 to March 2023 in our hospital. Among them, 14 were boys and 6 were girls, 17 were femoral neck lesions and 3 were femoral head lesions. The age of the patients ranged from 3.2 to 12.6 years, with a mean of 7.1 years. The patients were divided into group A and group B according to different surgical approaches; group A used the Smith-Peterson approach, Watson-Jones approach or surgical dislocation approach and group B used the DAA. Intra-operatively, incision length, operative time and blood loss were recorded in both groups. Group A consisted of 1 femoral head lesion and 8 femoral neck lesions, including 5 cases of bone cyst and 4 cases of eosinophilic granuloma. Group B consisted of 2 femoral head lesion and 9 femoral neck lesions. A total of 11 patients with different types of disease were included in group B, including bone cysts (3 cases), aneurysmal bone cysts (1 case), eosinophilic granulomas (6 cases), Kaposi's sarcoma (1 case). RESULTS: The two groups of patients differed in terms of incision length (P < 0.05), operative blood loss (P < 0.05) and operative time (P < 0.05). At 6-48 months post-operatively, there were no significant differences in function and all patients had good hip function. CONCLUSION: The direct anterior approach is effective for resection of paediatric femoral head and neck lesions. It provides clear exposure of the surgical site, minimal trauma and does not compromise the integrity of the anterior musculature. LEVEL OF EVIDENCE: III.

Lower Risk of Revision With 32- and 36-Millimeter Femoral Heads Compared With 28-mm Heads in Primary Total Hip Arthroplasty: A Comparative Single-Center Study (10,104 Hips).

BACKGROUND: We aimed to compare the clinical outcomes of different head sizes (28-, 32-, and 36- millimeter) in primary total hip arthroplasty (THA) at mean 6 years follow-up (range, 1 to 17.5 years). METHODS: This was a retrospective consecutive study of primary THA at our institution (2003 to 2019). Demographic and surgical data were collected. The primary outcome measures were all-cause revision, revision for dislocation, and all-cause revision excluding dislocation. Continuous descriptive statistics used means, median values, ranges, and 95% confidence intervals, where appropriate. Kaplan-Meier survival curves were used to estimate time to revision. Cox proportional hazard regression analyses were used to compare revision rates between the femoral head size groups. Adjustments were made for age at surgery, sex, primary diagnosis, American Society of Anesthesiologists score, articulation type, and fixation methods. There were 10,104 primary THAs included; median age was 69 years (range, 13 to 101) with 61.5% women. A posterior approach was performed in 71.6%. There were 3,295 hips with 28-mm heads (32.6%), 4,858 (48.1%) with 32-mm heads, and 1,951 (19.3%) with 36-mm heads. RESULTS: Overall rate of revision was 1.7% with the lowest rate recorded for the 36-mm group (2.7 versus 1.3 versus 1.1%). Cox regression analyses showed a decreased risk of all-cause revision for 32 and 36-mm head sizes as compared to 28-mm; this was statistically significant for the 32-mm group (P = .01). Risk of revision for dislocation was significantly reduced in both 32-mm (P = .03) and 36-mm (P = .03) head sizes. Analysis of all cause revision excluding dislocation showed no significant differences between head sizes. CONCLUSIONS: We found a significantly reduced risk of revision for all causes, but particularly revision for dislocation with larger head sizes. Concerns regarding increased risk of early revision for aseptic loosening, polyethylene wear, or taper corrosion with larger heads appear to be unfounded in this cohort of 10,104 patients with up to 17 years follow-up.

The small screw-apex distance is potentially associated with femoral head osteonecrosis in adults with femoral neck fractures treated by closed reduction and percutaneous 3 parallel cannulated screws.

OBJECTIVE: Femoral neck fractures (FNFs) are among the most common fractures in elderly individuals. Surgery is the main treatment for FNFs, and osteonecrosis of the femoral head (ONFH) is one of the unacceptable complications. This study aimed to assess both the clinical and radiological outcomes in patients with FNFs treated with three parallel cannulated screws and to identify relationship between screws position and ONFH. PATIENTS AND METHODS: A total of 100 patients who were treated with closed reduction and fixed with 3 parallel cannulated screws met the inclusion criteria between January 2014 and December 2020 at authors' institution. The follow-up duration, age, sex, affected side, and injury-to-surgery interval were collected; the neck-shaft angle of both hips, screw-apex distance (SAD) and the tip-apex distance (TAD)were measured; and the Garden classification, quality of reduction and presence of ONFH were evaluated. RESULTS: The sample consisted of 37 males and 63 females, with 60 left and 40 right hips affected. The mean age of patients was 54.93 ± 12.24 years, and the mean follow-up was 56.3 ± 13.38 months. The overall incidence of ONFH was 13%. No significant difference was observed in the incidence of ONFH by affected side, age, fracture displacement, injury-to-surgery interval, neck-shaft angle deviation, or reduction quality. The SAD was significantly shorter in ONFH patients than in normal patients for all three screws (p = 0.02, 0.02, and 0.01, respectively). CONCLUSIONS: The short SAD of all screws is associated with femoral head necrosis of FNFs treated with 3 cannulated screws. The short SAD indicated that screws malpositioning in the weight-bearing area of the femoral head, potentially harming the blood supply and compromising the anchorage of the primary compressive trabeculae in this region.

Arthroscopic Femoral Head Allograft With Proximal Femoral/Periacetabular Osteotomies for Sequelae of Perthes: A Case Report.

CASE: We describe the unique case of a 20-year-old man with a history of Legg-Calve-Perthes disease, hip dysplasia, and osteochondral fragmentation of the medial femoral head. We performed arthroscopic femoroplasty and femoral head allografting, followed by a valgus-producing derotational femoral osteotomy (DFO) and periacetabular osteotomy (PAO). At 1-year follow-up, the patient achieved osseous union and complete femoral head healing with return to his active hobbies. CONCLUSION: We describe the successful utilization of arthroscopic allografting for medial femoral head osteochondral fragmentation. To our knowledge, this is the first report on femoral head arthroscopic allografting before DFO and PAO.

Techniques and results of reconstruction of femoral head fractures: An Update.

A narrative review of the literature was conducted to examine the data on femoral head fractures, with a particular focus on their management, complications and clinical outcomes. A PRISMA strategy was used. Medline and Scopus library databases were queried using pre-defined MeSH terms and Boolean operators. Quality of evidence was evaluated based on OCEBM and GRADE systems. The 50 eligible articles that met the predefined inclusion criteria reported on 1403 femoral head fractures. A detailed analysis of the surgical approaches used was performed in 38 articles with 856 fractures. Most fractures were treated surgically (90,8 %) with preferred anatomical reconstruction in 76,7 % of all operatively treated cases. Posterior approaches were the most common (52.5 %). This was evenly split between surgical hip dislocation and the classic Kocher-Langenbeck approach. 70.5 % of surgically treated cases achieved excellent or good result according to Thompson-Epstein criteria. Highest rate of excellent results showed minimal invasive osteosynthesis and surgical hip dislocation. Major late complications were avascular necrosis (10.8 %), post-traumatic arthritis (16.2 %) and heterotopic ossification (20.8 %). Secondary THA was necessary in 6.9 %. Highest rate of major complications was joined with anterior approach (77 %), lowest rate from frequently used approaches surgical hip dislocation (37.8 %). Conservative treatment recedes into the background. The Ganz flip osteotomy with surgical hip dislocation allows safe treatment of all types of fractures and should be considered the first choice, offering the lowest rate of complications and one of the best functional outcomes. Reconstruction of Pipkin Type III fractures should be reserved for very young patients due to high rate of major complications.

Computer-Assisted Arthroscopic Cam Resection.

Determining the appropriate femoral cam resection during hip arthroscopy for femoroacetabular impingement syndrome is both critical for the patient and challenging for the surgeon. Incomplete bone resection is a leading cause of failed hip arthroscopy, whereas over-resection may increase the risk of femoral neck fracture. The alpha angle is a validated 2-dimensional radiographic measurement used to both diagnose femoroacetabular impingement syndrome preoperatively and to determine resection adequacy postoperatively. Computer-assisted intraoperative guidance systems enhance the accuracy of femoral cam resection, although a preoperative 3-dimensional computed tomography scan may be required. Other systems, such as the HipCheck software (Stryker, Kalamazoo, MI), have been developed to provide intraoperative guidance with live feedback using simultaneous alpha angle measurements overlayed on fluoroscopic images without the requirement for routine preoperative computed tomography. Via intraoperative touchscreen navigation, the surgeon identifies the midpoint of the femoral neck and femoral head. A commercial software program provides real-time alpha angle measurements, as well as enhanced visualization of the femoral cam deformity with an adjustable resection curve. Before the surgeon performs the cam resection, the software provides a template for appropriate resection depth in 6 positions of the hip. Upon completion of the femoral cam resection, the hip is again assessed in the same 6 positions and the alpha angle is assessed to ensure a complete resection.

Time elapsed from definitive diagnosis to surgery for osteonecrosis of the femoral head: a nationwide observational study in Japan.

OBJECTIVES: This study documents the time elapsed from the diagnosis of osteonecrosis of the femoral head (ONFH) to surgery, exploring the factors that influence ONFH severity. DESIGN: Retrospective observational study of a nationwide database. SETTING: The Kaplan-Meier method with log-rank tests was applied to examine the period from definitive diagnosis of ONFH to surgery using any surgery as the end point. For bilateral cases, the date of the first surgery was the endpoint. PARTICIPANTS: This study included 2074 ONFH cases registered in 34 university hospitals and highly specialised hospitals of the multicentre sentinel monitoring system of the Japanese Investigation Committee between 1997 and 2018. MAIN OUTCOME MEASURE: The primary outcome was the time from diagnosis to surgery. The secondary outcome was the proportion of subjects remaining without surgery at 3, 6 and 9 months, and at 1, 2 and 5 years after diagnosis. RESULTS: The median time to surgery was 9 months (IQR 4-22 months) after diagnosis of ONFH. The time to surgery was significantly shorter in the alcohol alone group and the combined corticosteroid and alcohol group than in the corticosteroid alone group (p=0.018 and p<0.001, respectively), in early stage ONFH with no or mild joint destruction (stages II and III, p<0.001), and with joint preserving surgery (p<0.001). The proportion without surgery was 75.8% at 3 months, 59.6% at 6 months, 48.2% at 9 months, 40.5% at 1 year, 22.2% at 2 years and 8.3% at 5 years. CONCLUSION: ONFH has been considered to be an intractable disease that often requires surgical treatment, but the fact that surgery was performed in more than half of the patients within 9 months from diagnosis suggests severe disease with a significant clinical impact. TRIAL REGISTRATION NUMBER: Chiba University ID1049.

Investigational regenerative medicine for non-traumatic osteonecrosis of the femoral head: a survey of registered clinical trials.

INTRODUCTION: Osteonecrosis of the femoral head (ONFH) is a refractory disease requiring joint replacement in young patients. Regenerative therapies have been developed. AREAS COVERED: This study surveyed clinical trials on regenerative medicine for ONFH. We extracted clinical trials on non-traumatic ONFH from the websites of five publicly available major registries (EuropeanUnion Clinical Trials Register ([EU-CTR],ClinicalTrials.gov, Chinese ClinicalTrial Registry [ChiCTR], University Hospital Medical InformationNetwork - Clinical Trial Registry [UMIN-CTR] and Australian New Zealand Clinical Trials Registry [ANZCTR]).The trials were classified into six categories based on purpose: surgical treatment, non-drug conservative treatment, conservative drug treatment, therapeutic strategy, diagnosis and pathogenesis, and regenerative therapy.) We extracted 169 clinical trials on ONFH. Of these, 37 were on regenerative medicine, including 29 on cell therapy. Surgical treatment was the most common treatment, followed by regenerative therapy.There were 9 clinical trials registered in the EU-CTR, with 5 on regenerative medicine; 79 trials registered on ClinicalTrials.gov, with 24 on regenerativemedicine; 54 trials registered in the ChiCTR, with 6 on regenerative medicine. EXPERT OPINION: The focus of the joint-preserving surgery has shifted to regenerative therapy based on using cell therapy in early-stage ONFH. The global standardisation of regenerative therapy is still ongoing.

Femoral Head Core Decompressions: Characterization of Subsequent Conversion to Total Hip Arthroplasty and Related Complications.

BACKGROUND: Core decompression is a minimally invasive joint-preserving approach for early-stage osteonecrosis. The rate at which core decompression patients require total hip arthroplasty (THA) and rates of perioperative adverse outcomes have not been well-characterized. METHODS: Adult patients undergoing core decompression and/or THA with osteonecrosis of the femoral head were identified from the 2015 to 2021 Q3 PearlDiver M157 database. Those undergoing THA without or with antecedent core decompression were identified and matched 4:1 on age, sex, and Elixhauser Comorbidity Index. Postoperative 90-day adverse events were compared with multivariable analysis. Five-year rates of revision, dislocation, and periprosthetic fracture were compared by the Kaplan-Meier curve and log-rank tests. RESULTS: Core decompressions were identified for 3,025 patients of whom 387 (12.8%) went on to THA within 5 years (64% within the first year). The median time from initial core decompression to THA was 252 days. For THA, 26,209 adults were identified and 387 had prior core decompression. After matching, there were 1,320 without core decompression and 339 with core decompression. No statistically significant differences were observed in 90-day postoperative adverse events or 5-year rates of revision, dislocation, or periprosthetic fracture. CONCLUSION: Core decompression may be an option for patients with osteonecrosis and does not seem to affect THA outcomes if required later.