Pathophysiology and natural history of avascular necrosis of bone

Pathological mechanisms and related markers of steroid-induced osteonecrosis of the femoral head

BACKGROUND

Osteonecrosis of the femoral head (ONFH) is a refractory orthopedic disease with a high disability rate. Long-term administration of steroids is the most common pathogenic factor for non-traumatic ONFH. Early diagnosis of steroid-induced osteonecrosis of the femoral head (SONFH) is difficult and mainly depends on imaging.

OBJECTIVES

The objectives of this review were to examine the pathological mechanisms of SONFH, summarize related markers of SONFH, and identify areas for future studies.

METHODS

We reviewed studies on pathological mechanisms and related markers of SONFH and discussed the relationship between them, as well as clinical applications and the outlook of potential markers.

RESULTS

The pathological mechanisms of SONFH included decreased osteogenesis, lipid accumulation, increased intraosseous pressure, and microcirculation disruption. Differential proteomics and genomics play crucial roles in the occurrence, progression, and outcome of SONFH, providing novel insights into SONFH. Additionally, the biological functions of mesenchymal stem cells (MSCs) and exosomes (Exos) in SONFH have attracted increasing attention.

CONCLUSIONS

The pathological mechanisms of SONFH are complex. The related markers mentioned in the current review can predict the occurrence and progression of SONFH, which will help provide effective early clinical prevention and treatment strategies for SONFH.

The impact of exosomes on bone health: A focus on osteoporosis

Osteoporosis is a widespread chronic condition. Although standard treatments are generally effective, they are frequently constrained by side effects and the risk of developing drug resistance. A promising area of research is the investigation of extracellular vesicles (EVs), including exosomes, microvesicles, and apoptotic bodies, which play a crucial role in bone metabolism. Exosomes, in particular, have shown significant potential in both the diagnosis and treatment of osteoporosis. EVs derived from osteoclasts, osteoblasts, mesenchymal stem cells, and other sources can influence bone metabolism, while exosomes from inflammatory and tumor cells may exacerbate bone loss, highlighting their dual role in osteoporosis pathology. This review offers a comprehensive overview of EV biogenesis, composition, and function in osteoporosis, focusing on their diagnostic and therapeutic potential. We examine the roles of various types of EVs and their cargo-proteins, RNAs, and lipids-in bone metabolism. Additionally, we explore the emerging applications of EVs as biomarkers and therapeutic agents, emphasizing the need for further research to address current challenges and enhance EV-based strategies for managing osteoporosis.

Updates in non-neoplastic orthopaedic pathology: what you don't know can hurt you!

Even though the average surgical pathologist reviews far more non-neoplastic orthopaedic pathology on a daily basis, most current research focuses on rare tumours and their even less frequent molecular events. Our experiences among consults and focused conferences strongly suggest that there remains a practice gap regarding knowledge and diagnosing specific non-neoplastic orthopaedic conditions. One of the most frequent intraoperative consultations performed in the USA, among both academic and private institutions, relates to revision arthroplasty and the determination of infection in periprosthetic joints. Pathologists play a critical role in this algorithm, helping determine intraoperatively whether patients require antibiotic spacers prior to reimplantation. Many pathology departments have abandoned the examination of arthroplasty specimens because they (and their surgeons) mistakenly believe there is little clinically relevant information to be gained by thorough pathological examination. However, recent literature has challenged this concept, emphasising the importance of distinguishing avascular necrosis (from osteoarthritis/degenerative joint disease with secondary osteonecrosis), subchondral insufficiency fracture, septic arthritis (from so-called 'sterile' osteomyelitis/pseudoabscesses), underlying crystalline diseases and incidental/occult neoplasia. Histological evaluation of historically insignificant orthopaedic specimens, such as tenosynovium from carpal tunnel syndrome/trigger finger, is now seen as valuable in early diagnosis of cardiac amyloidosis. Not infrequently, orthopaedic conditions like haemosiderotic synovitis, osteocartilaginous loose bodies or rheumatoid nodules, may histologically mimic bona fide neoplasms, notably diffuse tenosynovial giant cell tumour, synovial chondromatosis and epithelioid sarcoma, respectively. Here is a review of the more common non-neoplastic orthopaedic conditions, those likely to be examined by the practising surgical pathologist, with updates and guidelines for establishing clinically relevant diagnoses.

Unveiling the uncommon: a case report of avascular necrosis in the triquetrum bone without trauma

Introduction and importance

Avascular necrosis (AVN) is a rare occurrence in the carpal region, especially in the triquetrum bone, which presents a diagnostic puzzle due to its infrequency and lack of trauma history. This case study explores the signs, diagnosis, and treatment of AVN in a healthy 22-year-old individual, emphasizing the need for early identification using suitable imaging methods.

Case presentation

A 22-year-old patient complained of persistent wrist pain, specifically on the ulnar side, without any history of injury. Clinical examination revealed tenderness without signs of inflammation, with normal sensation and movement. Initial X-ray results were inconclusive, prompting further investigation with MRI, which showed a decrease in signal intensity in the triquetrum bone, leading to the diagnosis of AVN.

Clinical discussion

The development of AVN involves compromised blood flow, often due to various factors. While AVN affecting carpal bones is uncommon, the triquetrum bone's robust blood supply typically protects against such conditions. However, this case highlights an exceptional occurrence. Gelberman's classification underscores the triquetrum's vascular nature, explaining why AVN is rare in this bone. MRI plays a crucial role in detecting AVN, especially when symptoms do not align with X-ray findings.

Conclusion

Avascular necrosis should be considered in carpal bones, even without a history of trauma, with a focus on MRI for early detection. Although AVN of the triquetrum is rare, this case underscores the importance of timely recognition and conservative management. Further research is necessary to establish optimal treatment strategies for this unusual presentation.

The Application of Magnetic Resonance Imaging in the Early and Accurate Diagnosis of Hip Joint Avascular Necrosis

Introduction Avascular necrosis (AVN) is characterized by the death (necrosis) of cellular bone components in the subchondral bone or epiphysis due to a lack of or an interruption of the blood supply. In routine practice, AVN is most frequently encountered in the femoral head. In this study, we aim to evaluate the application of magnetic resonance imaging (MRI) in the early and accurate diagnosis of hip joint AVN. Materials and methods This was a retrospective, cross-sectional study conducted in the Department of Radiodiagnosis of Dr. D. Y. Patil tertiary care hospital, Pimpri, Pune, India. We studied 30 patients with complaints of pain and associated limping who underwent primary radiograph analysis of the hip joint, followed by MRI. Results We assessed 30 patients (45 hip joints) using plain radiography and MRI. Of the 45 hips, we could diagnose AVN in 28 hips (62.2%) using plain radiography, but we could not diagnose it in 17 hips (37.8%), whereas we were able to diagnose AVN in all hips (100%) using MRI. Forty percent of the patients (n = 12) were on steroids, 26.7% (n = 8) were chronic alcoholics, and 16.7% (n = 5) were idiopathic. The other less common causes were a history of trauma or fracture of the neck of the femur (n = 3) and sickle cell disease (n = 2). Of the 45 hips of the 30 patients studied, 15 patients had bilateral disease affecting a total of 30 hips (66.7%), and 15 patients had unilateral disease affecting a total of 15 hips (33.4%). Of the 30 hips (bilateral disease), five (13.3%) contralateral hips were clinically occult and were incidentally diagnosed with AVN. Conclusion The assessment of AVN based solely on plain radiography can miss vital information in stages II and III (Ficat and Arlet classification). Due to its multiplanar capability, superior spatial resolution, and better tissue characterization, MRI is very sensitive and able to detect femoral head AVN early and promptly in cases that are radiograph-negative or otherwise clinically unsuspected.

Causal relationship between telomere length and osteonecrosis: Bidirectional two-sample Mendelian randomization analysis

Recent mounting evidence suggests that shortening of telomere length (TL) is associated with impaired bone health; yet, a genetic causal relationship between TL and osteonecrosis remains uncertain. This study aimed to investigate the potential causal relationship between TL and osteonecrosis using bidirectional two-sample Mendelian randomization (MR). Genome-wide association study summary statistics for TL were sourced from the IEU Open genome-wide association study project, while osteonecrosis data were obtained from the FinnGen Biobank database. A range of MR methodologies-including inverse variance weighting, MR-Egger, weighted median, simple mode, and weighted mode-were utilized for analysis, along with the MR-Egger intercept method for horizontal pleiotropy assessment, and Cochran Q and leave-one-out methods for heterogeneity testing. The forward MR analysis indicated a significant causal relationship between TL and osteonecrosis, suggesting that genetically predicted shorter TL is associated with an elevated risk of developing osteonecrosis (OR = 0.611, 95% confidence interval 0.394-0.948, P = .028). The reverse MR analysis revealed no significant influence of osteonecrosis on TL (OR = 0.999, 95% confidence interval 0.994-1.005, P = .802). Analyses for heterogeneity and horizontal pleiotropy yielded robust results. Our study demonstrates that individuals with shorter TL have an increased risk of developing osteonecrosis, whereas osteonecrosis has no effect on TL.

Management of osteonecrosis of the humeral head in the pediatric population: A systematic review

Purpose

Humeral head osteonecrosis in the pediatric patients most often occurs in patients with underlying hemoglobinopathies, exposure to chronic corticosteroids, or after trauma. The purpose of this study was to perform a systematic review evaluating the prevalence, clinical characteristics, and management of humeral head osteonecrosis in the pediatric population.

Methods

PubMed, Ovid MEDLINE, and Scopus were screened with the terms "osteonecrosis," "avascular necrosis," "pediatric," and "proximal humerus" on January 10, 2024. A total of 218 studies were screened, and 74 studies were evaluated for eligibility. Studies that reported on the prevalence and/or management of pediatric humeral head osteonecrosis were included. The systematic review was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines.

Results

Twelve studies met inclusion criteria: four retrospective case series, three prospective case series, one retrospective cohort study, one retrospective case-control study, and three case reports. A majority of the studies (67%) discussed chemotherapy-induced osteonecrosis of the humeral head. A total of 77 patients (106 shoulders) with humeral head osteonecrosis were identified. The overall prevalence of osteonecrosis of the humeral head across eight studies examining at-risk populations (underlying hemoglobinopathies or undergoing chemotherapy) was 2%. Intra-articular steroid injections, physical therapy, and activity modification are effective conservative management strategies. Additionally, core decompression and hemiarthroplasty are surgical treatment options.

Conclusions

The prevalence of osteonecrosis of the humeral head is low even among at-risk populations with associated medical conditions. A variety of conservative and surgical treatment options have been described, but no comparative evaluations of these modalities has been conducted.

Level of evidence

IV.

Risk factors of preoperative deep vein thrombosis in patients with non-traumatic osteonecrosis of the femoral head

PURPOSE

This study aims to identify independent risk factors for preoperative lower extremity deep venous thrombosis (DVT) in patients with non-traumatic osteonecrosis of the femoral head (NONFH), and to develop a prediction nomogram.

METHODS

Retrospective analysis of prospectively collected data on patients presenting with non-traumatic osteonecrosis of the femoral head between October 2014 and April 2019 was conducted. Duplex ultrasonography (DUS) was routinely used to screen for preoperative DVT of bilateral lower extremities. Data on demographics, chronic comorbidities, preoperative characteristics, and laboratory biomarkers were collected. Univariate analyses and multivariate logistic regression analyses were used to identify the independent risk factors associated with DVT which were combined and transformed into a nomogram model.

RESULT

Among 2824 eligible patients included, 35 (1.24%) had preoperative DVT, including 15 cases of proximal thrombosis, and 20 cases of distal thrombosis. Six independent risk factors were identified to be associated with DVT, including Sodium ≤ 137 mmol/L (OR = 2.116, 95% confidence interval [CI]: 1.036-4.322; P = 0.040), AGE ≥ 49 years (OR = 7.598, 95%CI: 1.763-32.735; P = 0.008), D-Dimer > 0.18 mg/L (OR = 2.351, 95%CI: 1.070-5.163; P = 0.033), AT III ≤ 91.5% (OR = 2.796, 95%CI: 1.387-5.634; P = 0.006), PLT ≥ 220.4*10⁹ /L (OR = 7.408, 95%CI: 3.434-15.981; P = 0.001) and ALB < 39 g/L (OR = 3.607, 95%CI: 1.084-12.696; P = 0.042). For the nomogram model, AUC was 0.845 (95%CI: 0.785-0.906), and C-index was 0.847 with the corrected value of 0.829 after 1000 bootstrapping validations. Moreover, the calibration curve and DCA exhibited the tool's good prediction consistency and clinical practicability.

CONCLUSION

These epidemiologic data and the nomogram may be conducive to the individualized assessment, risk stratification, and development of targeted prevention programs for preoperative DVT in patients with NONFH.

The Hawkins Sign of the Talus: The Impact of Patient Factors on Prediction Accuracy

BACKGROUND

Osteonecrosis is a complication of talar neck fractures associated with chronic pain and poor functional outcomes. The Hawkins sign, the radiographic presence of subchondral lucency seen in the talar dome 6 to 8 weeks after trauma, is a strong predictor of preserved talar vascularity. This study sought to assess the accuracy of the Hawkins sign in a contemporary cohort and assess factors associated with inaccuracy.

METHODS

A retrospective review of talar neck fractures at a level-I trauma center from 2008 to 2016 was conducted. Both the Hawkins sign and osteonecrosis were evaluated on radiographs. The Hawkins sign was determined on the basis of radiographs taken approximately 6 to 8 weeks after injury, whereas osteonecrosis was determined based on radiographs taken throughout follow-up. The Hawkins sign accuracy was assessed using proportions with 95% confidence intervals (CIs), and associations were examined with Fisher exact testing.

RESULTS

In total, 105 talar neck fractures were identified. The Hawkins sign was observed in 21 tali, 3 (14% [95% CI, 3% to 36%]) of which later developed osteonecrosis. In the remaining 84 tali without a Hawkins sign, 32 (38% [95% CI, 28% to 49%]) developed osteonecrosis. Of the 3 tali that developed osteonecrosis following observation of the Hawkins sign, all were in patients who smoked.

CONCLUSIONS

A positive Hawkins sign may not be a reliable predictor of preserved talar vascularity in all patients. We identified 3 patients with a positive Hawkins sign who developed osteonecrosis, all of whom were smokers. Factors impairing the restoration of microvascular blood supply to the talus may lead to osteonecrosis despite the presence of preserved macrovascular blood flow and an observed Hawkins sign. Further research is needed to understand the factors limiting Hawkins sign accuracy.

LEVEL OF EVIDENCE

Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Effect of Patient Age on Total Hip Arthroplasty Outcomes in Patients Who Have Osteonecrosis of the Femoral Head Compared to Patients Who Have Hip Osteoarthritis

BACKGROUND

Osteonecrosis of the femoral head (ONFH) affects both young and old patients. However, outcomes following total hip arthroplasty (THA) for these patients may vary with age. This study aimed to examine the effect of age on THA outcomes for non-traumatic ONFH patients, an area currently lacking research.

METHODS

Patients who had non-traumatic ONFH undergoing THA with at least 2 years of follow-up were identified using a database and divided into four groups by age. Then, 4 matched control groups of patients who had hip osteoarthritis (OA) were created. Multivariate logistic regression analyses were used to evaluate the rates of medical and surgical complications. Additionally, cohorts with a minimum 5-year follow-up were filtered to obtain further data on surgical outcomes. The study analyzed 85,462 non-traumatic ONFH and 80,120 hip OA patients undergoing THA.

RESULTS

Multiple medical complications in ONFH patients increased with age. Periprosthetic fracture within 2 years increased with age, while 90-day wound complications, 2-year periprosthetic joint infections, dislocations, and revisions decreased. The trends for complications continued at the 5-year follow-up. Compared to OA patients, those who had ONFH had higher risks of most complications, but this discrepancy decreased with age.

CONCLUSIONS

In ONFH patients undergoing THA, medical complications generally rise with age, while most surgical complications, including revisions, decrease. It is notable that ONFH patients experienced more complications than those who had OA, but this difference diminished with age.

Talar Neck Fractures With Associated Ipsilateral Foot and Ankle Fractures Have a Higher Risk of Avascular Necrosis

OBJECTIVES

To determine if talar neck fractures with concomitant ipsilateral foot and/or ankle fractures (TNIFAFs) are associated with higher rates of avascular necrosis (AVN) compared with isolated talar neck fractures (ITNs).

METHODS

DESIGN

Retrospective cohort.

SETTING

Single level I trauma center.

PATIENT SELECTION CRITERIA

Skeletally mature patients who sustained talar neck fractures from January 2008 to January 2017 with at least 6-month follow-up. Based on radiographs at the time of injury, fractures were classified as ITN or TNIFAF and by Hawkins classification.

OUTCOME MEASURES AND COMPARISONS

The primary outcome was the development of AVN based on follow-up radiographs, with secondary outcomes including nonunion and collapse.

RESULTS

There were 115 patients who sustained talar neck fractures, with 63 (55%) in the ITN group and 52 (45%) in the TNIFAF group. In total, 63 patients (54.7%) were female with the mean age of 39 years (range, 17-85), and 111 fractures (96.5%) occurred secondary to high-energy mechanisms of injury. There were no significant differences in demographic or clinical characteristics between groups ( P > 0.05). Twenty-four patients (46%) developed AVN in the TNIFAF group compared with 19 patients (30%) in the ITN group ( P = 0.078). After adjusting for Hawkins classification and other variables, the odds of developing AVN was higher in the TNIFAF group compared with the ITN group [odds ratio, 2.43 (95% confidence interval, 1.01-5.84); ( P = 0.047)].

CONCLUSIONS

This study found a significantly higher likelihood of AVN in patients with talar neck fractures with concomitant ipsilateral foot and/or ankle fractures compared to those with isolated talar neck fractures after adjusting for Hawkins classification and other potential prognostic confounders.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Tooth extraction within 2 weeks before radiotherapy and osteoradionecrosis: A nationwide cohort study

OBJECTIVES

The theory of at least 2-week waiting period between tooth extraction and head and neck radiotherapy could reduce osteoradionecrosis remains controversial. Thus, this study examined the theory and associated factors.

MATERIALS AND METHODS

Data were retrieved from the National Health Insurance Research Database, Taiwan Cancer Registry Database, and Cause of Death Statistics. We included 24,353 patients with head and neck cancer who received radiotherapy from 2011 to 2017 and were followed up until 2019. The patients were divided into three groups: those undergoing tooth removal 2-8 weeks before radiotherapy, those undergoing tooth removal within 2 weeks before radiotherapy, and others. Confounding factors were clinical information, physical conditions, and risky habits. We used the Cox regression model to assess osteoradionecrosis risk.

RESULTS

No significant difference in osteoradionecrosis risk was observed between those undergoing tooth extraction within 2 weeks before radiotherapy and the other groups. An irradiation dose of ≥60 Gy, chemotherapy, tumor excision, post-radiotherapy tooth extraction, mandibulectomy, hyperlipidemia, and oral cavity as the tumor subsite were significantly positively associated with osteoradionecrosis risk.

CONCLUSION

A waiting period of ≥2 weeks between tooth extraction and radiotherapy did not significantly reduce osteoradionecrosis risk.

Natural course of talar avascular necrosis during short-term follow-up and factors associated with Disease progression

BACKGROUND

This retrospective cohort study aimed to investigate the natural history of talar avascular necrosis (AVN) during short-term outpatient follow-up and to identify the risk factors for progression to collapse and arthritic changes.

METHODS

Thirty-four cases of talar AVN from 34 patients (15 males, 19 females) were included. The mean age of the patients was 48.9 years (SD 16.0 years) and the mean follow-up period was 39.5 months (SD 42.0 months). The patients were divided into two groups i.e., progression and non-progression groups. The progression group consisted of those who showed aggravation of the Ficat stage during the follow-up period or advanced arthritis of the ankle joint (Ficat stage 4) at presentation. Demographic data and information regarding BMI, medical comorbidities, trauma history, bilaterality, and location of the lesion (shoulder vs. non-shoulder lesions) were collected. Following the univariate analysis, a binary logistic regression analysis was performed.

RESULTS

The location of the talar AVN was the only significant factor (p = 0.047) associated with disease progression. A total of 14.3% (2 of 14) of the central (non-shoulder) talar AVN lesions showed progression, while 50% (10 of 20) of shoulder lesions aggravated during follow-up. Age, sex, bilaterality, medical comorbidities, and trauma history were not associated with progressive talar collapse or subsequent arthritic changes in talar AVN.

CONCLUSIONS

Conservative treatment should be considered for a central lesion of the talar AVN because it tends to remain stable without progression. A more comprehensive study with a larger study population is required to establish the surgical indications for talar AVN.

LEVEL OF EVIDENCE

Prognostic level III.

A Narrative Review of Osteonecrosis of the Jaw: What a Clinician Should Know

Medication-related osteonecrosis of the jaw (MRONJ) is an uncommon complication of antiresorptive therapy (ART) in patients receiving higher and more frequent doses of osteoclast inhibitors. The jaws are the most common site, as they have high bone turnover. The oral structures are exposed to various types of stresses, like mastication and dental diseases, which lead to microtrauma and increased bone remodeling. The hallmark feature of MRONJ is the area of exposed, necrotic, nonhealing, asymptomatic bone for more than eight weeks. Objective signs are pain in the jaw and oral cavity, loose teeth, gingival swelling, ulceration, soft tissue infection, and paresthesia in the trigeminal nerve branches' territory. Clinically, the MRONJ has been defined in four stages, from stage 0 to stage 3. Close coordination between the dentist and oncologist is critical for optimal treatment. Conservative management should be preferred over surgical management. There is significant underreporting and misdiagnosis of MRONJ cases in regular clinical practice. There needs to be more awareness among treating physicians about this sporadic complication of bisphosphonate therapy. This narrative review has given a detailed insight into the subject, starting with etiology, pathogenesis, incidence, clinical presentation, workup, staging, and various management strategies. The review article focuses mainly on practical aspects of MRONJ, which every clinician dealing with the disease must know. With a better awareness of this potential complication, healthcare practitioners dealing with at-risk patients can better diagnose, prevent, address, and provide necessary care.

Caring for the Bone Health Among Liver Transplant Recipients

Liver transplant outcomes have improved over the years, and currently, the quality of life and long-term well-being of these patients needs to be improved. Improving bone health goes a long way toward achieving this objective. Poor bone health (osteopenia and osteoporosis) although prevalent, is often overlooked owing to its asymptomatic nature. It can be complicated by debilitating fracture affecting quality of life. It is recommended to assess and optimize bone health prior to liver transplant. Multiple factors contribute to poor bone health in a liver transplant recipient and it is vital to understand and ameliorate these. A careful and targeted approach with inputs from multidisciplinary team involving transplant physician, endocrinologist, occupational therapist, nutritionist, and nursing personnel may often be required. In this review, we aim to concisely discuss the various aspects related to prevalence, pathophysiology, evaluation, treatment, and follow-up of bone disease among liver transplant recipients.

Perioperative Complications of Pediatric Orthopaedic Surgery in Sickle Cell Disease

BACKGROUND

Vasoocclusion in sickle cell disease can be precipitated by cold temperatures, hypoxia, infection, dehydration, and stress, all of which can occur in the setting of surgery. The purpose of this study was to identify predictors of perioperative complications among pediatric patients with sickle cell disease undergoing orthopaedic surgery.

METHODS

An institutional review board approved single-center retrospective review was conducted of pediatric patients 21 years of age and younger with SCD who underwent any orthopaedic surgery at a single center between 2009 and 2019. Patient data and procedure-specific information were recorded. Preoperative admission for hydration and/or blood transfusion and preoperative laboratory studies were reviewed. The primary study outcome was postoperative complications within 30 days of surgery requiring an ED visit or hospital admission.

RESULTS

Ninety-two patients who underwent 118 orthopaedic surgeries were identified. The average age at surgery was 12.0 years (SD 4.8 y). Surgical cases were classified as elective (n=82, 70%), infection (n=26, 22%), and trauma (n=9, 8%). The lower extremity was the most frequent surgical site (n=86, 73%). Sixty surgeries (51%) received a preoperative blood transfusion. There were 19 surgeries with postoperative complications (16%) that required an ED visit or hospital readmission within 30 days of surgery. There were significantly more complications following surgery on the hip as compared with other sites (24% vs. 9%, P =0.04). Four or more ED visits in the past year were associated with an OR of 5.7 for a postoperative complication ( P =0.01, 95% CI 1.6-20.5). Patients who had a preoperative blood transfusion had significantly greater rates of complications than those that did not (27% vs. 5%, P <0.01).

CONCLUSIONS

Children with SCD are at increased risk for complications after orthopaedic surgery, and the current study found an overall postoperative complication rate of 16%. Patients undergoing hip surgery had a disproportionate number of complications, with a 5.8-fold increased risk of a postoperative complication. Patients with 4 or more ED visits in the past year had a 5.7-fold increased risk of a complication.

LEVEL OF EVIDENCE

IV Retrospective case series.

Reductions in Bone Mineral Density Are Apparent Early in Children With Prevalent Osteonecrosis Lesions Following Leukemia Therapy

Osteonecrosis (ON) is a serious complication of childhood acute lymphoblastic leukemia. We determined the prevalence of osteonecrotic lesions in our patient population by a one-time multisite magnetic resonance imaging (MRI) more than 1 year following leukemia therapy. MRI findings were evaluated in relationship to clinical factors (including longitudinal changes in bone mineral density [BMD]). Eighty-six children enrolled in the Steroid Associated Osteoporosis in the Pediatric Population (STOPP) study were evaluated for ON at 3.1 ± 1.3 years following therapy. Thirty children had a total of 150 confirmed ON lesions (35%). Lumbar spine (LS) BMD Z-scores (mean ± SD) were low at diagnosis and similar between patients with and without ON (-1.09 ± 1.53 versus -1.27 ± 1.25, p = 0.549). LS BMD Z-scores declined from baseline to 12 months in children with ON (-0.31 ± 1.02) but not in those without (0.13 ± 0.82, p = 0.035); the hip BMD Z-scores from baseline to 24 months declined in both groups, but to a greater extent in those with ON (-1.77 ± 1.22) compared to those without (-1.03 ± 1.07, p = 0.045). At the time of the MRI, mean total hip and total body (TB) BMD Z-scores were lower in children with ON (hip -0.98 ± 0.95 versus -0.28 ± 1.06, p = 0.010; TB -1.36 ± 1.10 versus -0.48 ± 1.50, p = 0.018). Pain occurred in 11/30 (37%) with ON versus 20/56 (36%) without, p = 0.841. In multivariable models, older age at diagnosis (odds ratio [OR] 1.57; 95% confidence interval [CI], 1.15-2.13; p = 0.004), and hip BMD Z-score at MRI (OR 2.23; 95% CI, 1.02-4.87; p = 0.046) were independently associated with ON. Overall, one-third of children demonstrated ON after leukemia therapy. Those with ON had greater reductions in spine and hip BMD Z-scores in the first 1 and 2 years of therapy, respectively. Older age and lower hip BMD Z-scores at MRI were significantly associated with prevalent, off-therapy ON. These data assist in identifying children at risk of ON. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Rare Bi-focal Presentation of Avascular Necrosis of the Femoral Head: Successful Targeted Treatment as per the Diamond Concept and Review of the Literature

Avascular necrosis of the femoral head (AVNFH) is relatively infrequent, but if undiagnosed or untreated, it may result in significant functional disability, and due to severe ongoing pain, a total hip replacement (THR) may be necessitated. Most cases are associated with trauma, but a number of established risk factors exist. Diagnosis can be challenging but relies on clinical history, physical examination, and radiology. X-ray and MRI are used to stage avascular necrosis (AVN) lesions, which in turn influence management decisions. We present a male in his early 40s, diagnosed with a right-sided AVNFH (Ficat-Arlet stage I) five years previously at another centre. A number of risk factors were identified, such as chronic alcohol abuse, smoking, obesity, and Klinefelter's syndrome. A 'watch and wait' approach was adopted, which included advice on reducing risk factors and commencement on aspirin and alendronic acid. However, his pain had recently increased, resulting in a significant reduction in mobility and an increased reliance on opiates. MRI demonstrated progression to Ficat-Arlet stage II, and the appearance of an additional smaller, second lesion located more medially in the same femoral head. Due to his symptom severity, he was offered a THR. In view of his young age, he came to our tertiary referral centre for a second opinion. He elected for a simultaneous dual surgical decompression of both AVN lesions and biological stimulation for bone-guided regeneration. This involved the delivery of growth factor (bone morphogenetic protein), progenitor cells, and a scaffold/matrix. At 36 months post-operatively, he continued to have the full, pain-free weight-bearing functional capacity, with radiographic imaging demonstrating no residual AVN or femoral head structural collapse. This was a unique case of bi-focal femoral head lesions, treated successfully with decompressions and biological enhancement using the 'diamond concept' for bone repair. In similar situations, when salvage of the femoral head is the preferred treatment option, such a strategy should be considered in the surgeon's armamentarium.

Case report: adipose-derived mesenchymal stem cells combined with core decompression in the treatment of early-stage avascular necrosis of the femoral head

INTRODUCTION

Core decompression is a well-known modality for treating the early stages of avascular necrosis of the femoral head (AVN), however, several methods have been suggested to augment this procedure and improve the outcomes.

CASE REPORT

A 52 male was diagnosed with a stage I AVN of the femoral head and treated with core decompression (CD) and injection of adipose-derived mesenchymal stem cells (AD-MSCs). The MRI showed full healing of the lesion after 3 months with significant clinical and functional improvement.

DISCUSSION

AD-MSCs could have the same capabilities as bone marrow-derived stem cells with many advantages, implantation of AD-MSCs in orthopedics and as an augmentation of core decompression has been tried before, but no clear guidelines nor methods of application are well established in the literature.

CONCLUSION

Implantation of AD-MSCs with Core decompression could be an effective modality to treat osteonecrosis of the femoral head in pre-collapse stages, however, we need bigger clinical studies to determine the actual effectiveness of this method.

Debilitating hip degeneration in trichothiodystrophy: Association with ERCC2/XPD mutations, osteosclerosis, osteopenia, coxa valga, contractures, and osteonecrosis

Trichothiodystrophy (TTD) is a rare, autosomal recessive, multisystem disorder of DNA repair and transcription with developmental delay and abnormalities in brain, eye, skin, nervous, and musculoskeletal systems. We followed a cohort of 37 patients with TTD at the National Institutes of Health (NIH) from 2001 to 2019 with a median age at last observation of 12 years (range 2-36). Some children with TTD developed rapidly debilitating hip degeneration (DHD): a distinctive pattern of hip pain, inability to walk, and avascular necrosis on imaging. Ten (27%) of the 37 patients had DHD at median age 8 years (range 5-12), followed by onset of imaging findings at median age 9 years (range 5-13). All 10 had mutations in the ERCC2/XPD gene. In 7 of the 10 affected patients, DHD rapidly became bilateral. DHD was associated with coxa valga, central osteosclerosis with peripheral osteopenia of the skeleton, and contractures/tightness of the lower limbs. Except for one patient, surgical interventions were generally not effective at preventing DHD. Four patients with DHD died at a median age of 11 years (range 9-15). TTD patients with ERCC2/XPD gene mutations have a high risk of musculoskeletal abnormalities and DHD leading to poor outcomes. Monitoring by history, physical examination, imaging, and by physical medicine and rehabilitation specialists may be warranted.

Pathophysiology of Avascular Necrosis

Avascular necrosis is a complicated, multifactorial disease with potentially devastating consequences. Although the underlying root cause is a lack of appropriate vascular perfusion to affected bone, there are often varying patient-specific, anatomic-specific, and injury-specific predispositions. These factors generally fall into 3 categories: direct vascular disruption, intravascular obliteration, or extravascular compression. The initial stages of disease can be insidiously symptomatic because edematous bone marrow progresses to subchondral collapse and subsequent degenerative arthritis. Although much of the current literature focuses on the femoral head, other common areas of occurrence include the proximal humerus, knee, and the carpus. The low-incidence rate of carpal avascular necrosis poses a challenge in establishing adequately powered, control-based validated treatment options, and therefore, optimal surgical management remains a continued debate among hand surgeons. Appreciation for expectant fracture healing physiology may help guide future investigation into carpal-specific causes of avascular necrosis.

Functional Outcomes for Children, Adolescents, and Young Adults with Osteonecrosis following Hip Core Decompression

Background

Patients with pediatric leukemia and sickle cell disease are at risk for developing osteonecrosis (ON), a disease that can result in pain, loss of function, and disability. Hip core decompression surgery is an option aimed to prevent femoral head collapse and avoid future arthroplasty.

Objective

Describe functional outcomes and gait quality among a young population with hip ON before and after hip core decompression.

Methods

Study included participants with hip ON secondary to treatment for hematologic malignancy or sickle cell disease, between 8 and 29 years old, requiring hip core decompression surgery. At one-year follow-up, 13 participants (9 male, median age 17 years) completed the Functional Mobility Assessment (FMA), range of motion, and GAITRite® testing.

Results

Participants demonstrated improved mobility and endurance on the FMA at 1-year post-operatively compared to pre-operatively, with higher scores for time on the Timed Up and Go (mean FMA score = 2.92 [SD = 1.32] vs. 2.07 [SD = 1.70]), time on the Timed Up and Down Stairs (3.69 [0.85] vs. 2.92 [1.66]), and 9-Minute Walk Test scores for distance walked (2.69 [0.63] vs. 2.23 [0.93]) and heart rate (4.54 [0.66] vs. 3.31 [1.38]). GAITRite® analysis also showed improvements in many gait parameters at one-year follow-up.

Limitations

Cancer treatment complications other than ON could have contributed to results, not all eligible participants agreed to participate, and follow-up was only one year.

Conclusions

Young patients with hip ON demonstrated improvements in functional mobility, endurance, and gait quality one year following hip core decompression.

[Osteonecrosis-severe side effect of treatment for acute lymphoblastic leukemia]

Osteonecrosis occurs as an acute and long-term serious side effect in children, adolescents, and adults with acute lymphoblastic leukemia. It is associated with severe pain and reduced mobility, ultimately leading to joint destruction and significant long-term morbidity. The cumulative incidence ranges from 11 to 20% in adolescents and young adults. In symptomatic patients, multiple joints are frequently affected, which in turns poses a risk factor for the development of severe osteonecrosis. The genesis of leukemia-associated osteonecrosis is multifactorial. Risk factors include the use of corticosteroids and asparaginase. These exert their effects on the blood supply to the bone through hypercholesterolemia, hypertriglyceridemia, and hypertension. Bacteriemia, genetic susceptibility, and stem cell transplantation pose additional risk factors. The treatment of osteonecrosis is challenging and not evidence based. Preventive measurements have as yet mainly been tested in preclinical models.

Fabrication of succinate-alginate xerogel films for in vitro coupling of osteogenesis and neovascularization

The osseointegration of metallic implants is reliant on a cascade of molecular interactions and the delivery of macromolecules to the implant environment that occurs before substantial bone formation. Early blood vessel formation is a requisite first step in the healing timeline for osteoid formation, where vascular development can be accelerated as a result of controlled hypoxic conditioning. In this study, alginate-derived xerogel films containing varied concentrations of disodium succinate salt which has been shown to induce pseudohypoxia (short-term hypoxic effects while maintaining an oxygenated environment) were developed. Xerogels were characterized for their morphology, succinate release over time and cellular response with osteoblast-mimicking Saos-2 and human umbilical vein endothelial cells (HUVEC). Scanning electron microscopy revealed a multiscale topography that may favour osseointegration and alamarBlue assays indicated no cytotoxic effects during in vitro proliferation of Saos-2 cells. pH measurements of eluted succinate reach 95 % of peak value after 7 h of immersion for all gels containing 10 mM of succinate or less, and 60 % within the first 40 min. In vitro exposure of HUVECs to succinate-conditioned media increased the net concentration of total proteins measured by bicinchoninic acid (BCA) assay and maintains stable vascular endothelial growth factor (VEGF) and extracellular platelet-derived growth factor (PDGF) for vessel formation through comparison of enzyme-linked immunosorbent assays (ELISAs) of the culture media and cell lysate. Tube formation assays also showed a sustained increase in tube diameter across the first 48 h of HUVEC culture when succinate concentrations of 1 and 10 μM in the xerogel. Overall, the succinate-alginate films serve as a prospective organic coating for bone-interfacing implant materials which may induce temporary pseudohypoxic conditions favourable for early angiogenesis and bone regeneration in vivo at succinate concentrations of 1 or 10 μM.

Undiagnosed Bilateral Avascular Necrosis of the Femur in a Young Male Caused by COVID-19 Steroid Injections

Osteonecrosis is a degenerative bone disease brought on by a change in subchondral blood flow and characterized by the loss of bone cellular components. Other names for it include ischemic bone necrosis, aseptic necrosis, and avascular necrosis. Long bones' epiphyses in weight-bearing joints are typically impacted. In extreme cases, a joint may completely collapse or subchondral bone may be obliterated. Avascular necrosis, which most frequently affects joints, especially the femoral head, occurs when the blood supply to the bones is diminished. In this article, we will explain the clinical case of a 40-year-old man who's been complaining about hip pain for two months. The patient went to Acharya Vinobha Bhave Rural Hospital (AVBRH) with the same complaint and underwent some tests; upon inspection, it was discovered that the patient had bilateral avascular femoral head necrosis. For avascular necrosis (AVN) of the left femoral head, the patient had core decompression surgery. Once post-operative physical therapy was initiated, the condition significantly improved, and it also served to prevent additional abnormalities. The goal of this case study is to examine the therapeutic strategies essential for treating bilateral femoral head avascular necrosis.

Subchondral involvement in osteonecrosis of the femoral head: insight on local composition, microstructure and vascularization

OBJECTIVE

To determine changes of subchondral bone composition, micro-structure, bone marrow adiposity and micro-vascular perfusion in end-stage osteonecrosis of the femoral head (ONFH) compared to osteoarthritis (OA) using a combined in vivo and ex vivo approach.

DESIGN

Male patients up to 70 years old referred for total hip replacement surgery for end-stage ONFH were included (n = 14). Fifteen patients with OA were controls. Pre-operative MRI was used to assess bone perfusion (dynamic contrast-enhanced (DCE) sequences) and marrow fat content (chemical shift imaging). Three distinct zones of femoral head subchondral bone - necrotic, sclerotic, distant - were compared between groups. After surgery, plugs were sampled in these zones and Raman spectroscopy was applied to characterize bone mineral and organic components (old and newly-formed), and contrast-enhanced micro-computed tomography (CE-μCT) to determine bone micro-structural parameters and volume of bone marrow adipocytes, using conventional 2D histology as a reference.

RESULTS

In the necrotic zone of ONFH patients compared to OA patients: 1) the subchondral plate did not exhibit significant changes in composition nor structure; 2) the volume fraction of subchondral trabecular bone was significantly lower; 3) type-B carbonate substitution was less pronounced, 4) collagen maturity was more pronounced; and 5) bone marrow adipocytes were significantly depleted. The sclerotic zone from the ONFH group showed greater trabecular thickness, and higher DCE-MRI AUC and K_trans. Volume fraction of subchondral bone, trabecular number, and K_ep were significantly lower in the distant zone of the ONFH group.

CONCLUSIONS

This study demonstrated alterations of subchondral bone microstructure, composition, perfusion and/or adipose content in all zones of the femoral head.

Bone microarchitecture and metabolism in elderly male patients with signs of intravertebral cleft on MRI

OBJECTIVES

Intravertebral cleft (IVC) is a common but not unique imaging manifestation in Kümmell's disease. To date, great controversy exists regarding the specific mechanisms of IVC. In this study, we aimed to investigate the characteristics of microarchitecture and metabolism in patients with IVC and to analyse the correlations between degree of vertebral collapse and risk factors.

METHODS

A total of 79 elderly men were included in this study. We divided all patients into two groups: the IVC group (30 patients) and the non-IVC group (49 patients). We compared the differences in microarchitecture and bone turnover marker (BTM) serum concentrations between the groups and analysed risk factors affecting vertebral collapse by using the Mann-Whitney U test and Spearman's correlation test.

RESULTS

Quantitative analysis of the microarchitecture showed higher content of necrotic bone (p < 0.001) and lower content of lamellar bone (p < 0.001) in the IVC group. Analysis of BTMs identified lower concentration of N-terminal propeptide of type I collagen (PINP, p = 0.002) and higher concentration of β-isomerized C-terminal telopeptide (β-CTX, p < 0.001) in the IVC group. The correlation analysis showed that lamellar bone content (p < 0.001) and spine T-score (p = 0.011) were significantly correlated with the degree of vertebral collapse.

CONCLUSIONS

IVC is a radiological feature of excessive bone resorption by higher activities of osteoclasts and decreased bone remodelling ability by lower activities of osteoblasts. Histomorphological feature in patients with IVC is delayed callus mineralisation, which may increase the risk of vertebral collapse.

KEY POINTS

• A key histomorphological feature in patients with IVC is delayed callus mineralisation, which may aggravate the degree of vertebral collapse. • We investigated bone metabolism in patients with IVC to evaluate the activities of osteoclasts and osteoblasts directly. • We propose a novel hypothesis for the pathogenesis of IVC: bone resorption by higher activity of osteoclasts and decreased callus mineralisation ability by lower activity of osteoblasts are the main mechanisms leading to IVC.

Classification and Management of Failed Fixation of the Volar Marginal Fragment in Distal Radius Fractures

Greater understanding of specific fracture patterns following distal radius fractures has arisen with the advent of volar plating. The volar marginal fragment (VMF) is a small peripheral piece of bone which is critical to carpal stability. Failure to achieve good fixation of the VMF can result in volar subluxation of the carpus and distal radioulnar joint instability. Due to its small, distal nature, this fragment can be easily missed and difficult to fix. Loss of reduction of the VMF following operative fixation presents specific challenges and surgical considerations dictated by patient characteristics and timing. Our goal of this review is to present a classification system for these failed VMFs which can help guide surgical treatment as well as expected outcomes.

Prevalence of and Associations With Avascular Necrosis After Pediatric Sepsis: A Single-Center Retrospective Study

OBJECTIVES

Avascular necrosis (AVN) is a rare, but serious, complication after sepsis in adults. We sought to determine if sepsis is associated with postillness diagnosis of AVN, as well as potential-associated risk factors for AVN in children with sepsis.

DESIGN

Retrospective observational study.

SETTING

Single academic children's hospital.

PATIENTS

Patients less than 18 years treated for sepsis or suspected bacterial infection from 2011 to 2017. Patients who developed AVN within 3 years after sepsis were compared with patients who developed AVN after suspected bacterial infection and with patients with sepsis who did not develop AVN.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

AVN was determined using International Classification of Diseases, 9th Edition/10th Edition codes and confirmed by chart review. The prevalence of AVN after sepsis was 0.73% (21/2,883) and after suspected bacterial infection was 0.43% (53/12,276; risk difference, 0.30; 95% CI, 0.0-0.63; p = 0.05). Compared with 43 sepsis controls without AVN, AVN in the 21 sepsis cases was associated with being older, having sickle cell disease and malignancy, higher body mass index, unknown source of infection, and low platelet count in the first 7 days of sepsis. Half of sepsis patients were treated with corticosteroids, and higher median cumulative dose of steroids was associated with AVN (23.2 vs 5.4 mg/kg; p < 0.01). Older age at infection (odds ratio [OR], 1.3; 95% CI, 1.1-1.4), malignancy (OR, 8.8; 95% CI, 2.6-32.9), unknown site of infection (OR, 12.7; 95% CI, 3.3-48.6), and minimal platelet count less than 100,000/µL in first 7 days of sepsis (OR, 5.0; 95% CI, 1.6-15.4) were identified as potential risk factors for AVN after sepsis following adjustment for multiple comparisons.

CONCLUSIONS

Although rare, sepsis was associated with a higher risk of subsequent AVN than suspected bacterial infection in children. Older age, malignancy, unknown site of infection, and minimum platelet count were potential risk factors for AVN after sepsis.

Value of SPECT/CT in the diagnosis of avascular necrosis of the head of femur: A meta-analysis

INTRODUCTION

To evaluate the diagnostic value of single photon emission computed tomography/computed tomography (SPECT/CT) in patients with avascular necrosis (AVN) of the femoral head.

METHODS

A search of the databases PubMed, ScienceDirect, and Google Scholar was undertaken using targeted index word. Studies satisfying inclusions and exclusions criteria were identified and additional related literature sources were considered. Analysis included pooled sensitivity and specificity, odds ratio (OR), and receiver operating characteristic (ROC) analysis.

RESULTS

Seven studies were identified that specifically related to the diagnostic accuracy of SPECT/CT in the detection or characterisation of AVN of the femoral head. These were included in the meta-analysis. The pooled sensitivity and specificity were 94% (95% confidence interval of 87-97%) and 75% (95% confidence interval of 68-81%) respectively, the OR was 44.5 (with a 95% confidence interval of 18.2-108.6), and the area under the SROC was 93.73% (with a 95% confidence interval of 89.2%-98.3%).

CONCLUSION

This meta-analysis provides strong evidence of the high diagnostic efficacy of SPECT/CT in the evaluation of AVN of the femoral head.

IMPLICATIONS FOR PRACTICE

In the absence of or contraindication to MRI, SPECT/CT is able to provide a suitable alternative for diagnosis of AVN of the head of femur.

Outcomes of Zoledronic Acid Use in Paediatric Conditions

INTRODUCTION

Limited evidence is available concerning experience with use of zoledronic acid (ZA) and treatment for conditions other than primary bone fragility.

MATERIALS AND METHODS

A retrospective review of all Royal Children Hospital patients who had been administered at least 1 dose of intravenous ZA from 2002 to 2015 was undertaken.

RESULTS

The audit included 309 children with 228 being treated for bone fragility conditions. Of the 228, 68 had height-adjusted lumbar spine bone mineral density Z-scores available over up to a 5-year period, and median increases were +2.0 SD (median absolute deviation = 0.9) (N = 36, p value for median increase of at least 0.5 in Z-score <0.001), for patients with osteogenesis imperfecta or other primary bone fragility disorders, +1.0 SD (0.9) (N = 14, p = 0.029), for immobility conditions, +0.5 SD (0.7) (N = 10, p = 0.399), and for glucocorticoid-induced secondary osteoporosis, +0.7 SD (0.6) (N = 8, p = 0.015). 81/309 children were treated for bone abnormality indications (e.g., avascular necrosis [AVN], fibrous dysplasia, and bone cysts). Of 39 with AVN, outcome data were available for 33, with joint integrity maintained for 24/33 from 6 to 24 months after last ZA, subjective reports (22/28) of reduced pain. Reduction in bone lesion size was seen in 2/4 patients with bone cysts within 12 months of ZA commencement.

DISCUSSION/CONCLUSION

This is the largest cohort of reported outcomes of ZA use in a paediatric population. Results demonstrate a good efficacy profile and associated improved bone density for osteoporotic conditions and stabilization of non-traumatic AVN with a low rate of joint collapse.

Medication-Related Osteonecrosis of the Jaw: A Critical Narrative Review

Background: Nearly two decades have passed since a paradoxical reaction in the orofacial region to some bone modifying agents and other drugs was recognized, namely medication-related osteonecrosis of the jaw (MRONJ). Purpose: The aim of this manuscript was to critically review published data on MRONJ to provide an update on key terminology, concepts, and current trends in terms of prevention and diagnosis. In addition, our objective was to examine and evaluate the therapeutic options available for MRONJ. Methods: The authors perused the most relevant literature relating to MRONJ through a search in textbooks and published articles included in several databases for the years 2003–2021. Results and conclusions: A comprehensive update of the current understanding of these matters was elaborated, addressing these topics and identifying relevant gaps of knowledge. This review describes our updated view of the previous thematic blocks, highlights our current clinical directions, and emphasizes controversial aspects and barriers that may lead to extending the accumulating body of evidence related to this severe treatment sequela.

Arthroscopic and open partial arthroplasty for the treatment of focal grade IV cartilage defects of the humeral head

INTRODUCTION

Focal Outerbridge grade IV cartilage defects of the proximal humerus may lead to pain and an impaired shoulder function. In cases of failed operative or conservative treatment options such as intraarticular injections or arthroscopic microfracturing of the subchondral bone, partial arthroplasty of the humeral may restore the articular surface of the humeral head without altering the anatomy. This study evaluates mid-term results of open and arthroscopic partial resurfacing of the humeral head in the context of focal grade IV cartilage defects.

METHODS

Eighteen patients (f = 3, m = 15, mean age = 57.7 years) out of 22 patients were available for follow-up after 65 (24-116) months. Thirteen patients were treated with a partial humeral head prosthesis in an open technique and five patients received a partial humeral head prosthesis in an arthroscopic technique. The patients were followed-up clinically using the Constant-Score, the ASES Score as well as the range of motion. Plain radiographs (anterior-posterior and axial view) were carried out for radiologic assessment.

RESULTS

At follow-up the mean CS rated 79.5. The mean ASES Score was 85.8 points. Mean active forward flexion measured 163.8°, while mean active abduction was 160.0°. The average pain level on a visual analogue scale (VAS) made out 0.7 out of 10. Patients treated with an arthroscopically implanted prosthesis achieved a mean CS of 88.8 points and a mean ASES Score of 92.6 points. The patients with openly implanted prosthesis had a CS of 75.3 points and an ASES Score of 83 points. There were no intraoperative or immediate postoperative complications. Until the final follow-up one patient needed to be converted to total shoulder arthroplasty due to progressive glenohumeral osteoarthritis. Nine patients (50%) showed progressive glenohumeral osteoarthritis. Aseptic loosening of the implants was not observed.

CONCLUSION

Partial arthroscopic or open arthroplasty of the humeral head is related to good functional results after mid-term follow-up. Resurfacing of the humeral head is a safe procedure without any implant-related complications. There is a risk for progression of glenohumeral osteoarthritis, which may require surgical revision with conversion to anatomic shoulder arthroplasty.

LEVEL OF EVIDENCE

Level IV (retrospective study).

Hip avascular necrosis in a healthy pregnant woman: A case report and review of literature

Background

Hip pain during pregnancy is very common, but hip avascular necrosis represents a very rare entity.

Case report

We report a rare case of a healthy30-year-old female patient pregnant with twins, that suffered right hip avascular necrosis in the peripartum period, her symptoms were initially neglected as a benign cause of hip pain, this led to aggressive treatment at a young age.

Discussion

With less than 100 cases reported in the literature, pregnancy is not a well-known risk factor for femoral head avascular necrosis and it should be differentiated from one of the more common hip pathologies in pregnancy which is the so-called “Pelvic pain syndrome” and transient osteoporosis of the hip.

Conclusion

Having a high index of suspicion and low threshold for MRI imaging in a pregnant woman with hip pain is a must to prevent such complications.

•

Corticosteroids and alcohol intake are the most common atraumatic cause of hip osteonecrosis

•

Hip and pelvic pain during pregnancy are very frequent and may hide a serious event such as hip avascular necrosis

•

Hip avascular necrosis can have disastrous complications if not diagnosed in young pregnant women.

•

Having a high index of suspicion in a pregnant woman with hip pain is a must to prevent such complications

Complex Polypathology Infectious, Rheumatological, Neurological and Orthopedic – Real Challenge for Functional Rehabilitation - Case Report

Introduction. Infectious and autoimmune rheumatic diseases (ARDs) are closely linked. Apart from the challenging, sometimes differential, diagnosis between these conditions, it is recognized that microbes play an important role in the pathogenesis of the latter. Material and method. We present the case of a 45-year-old female patient from our rehabilitation department, with complex pathology (infectious, neurological, rheumatological and orthopedic pathology) that began more than 15 years ago. The patient’s pathological history began insidiously at theage of 30 when she was diagnosed with neurotoxoplasmosis. She received anticoagulant, antiepileptic, steroidal, antibiotic and antihelmintic treatment. After four years, the patient shows insidious onset of inflammatory pain in the large joints and in 2010 is diagnosed with seropositive rheumatoid arthritis, according to American College of Rheumatism/European League against rheumatism (ACR/EULAR) criteria with symmetric impairment of the large joints (shoulder, elbow, hip, knee, ankle). Despite the treatment with disease-modifying anti-rheumatic drugs (DMARDs) received, in the following years she needed 4 arthroplasties in the large joints due to osteonecrosis. Conclusions. On clinical grounds, infections, especially chronic infections, can cause a plethora of autoimmune phenomena, thus mimicking ARDs. Therefore, the differential diagnosis between ARDs and infectious diseases is sometimes challenging as they often display similar clinical manifestations. It is highlighted that the immune system can be our friend or our foe considering that its function and dysregulation are the common denominators in autoimmune and infectious diseases. In the era of new drugs and new therapeutic strategies, safety of the patients should always be our first concern.

Etiology of avascular osteonecrosis of the femoral head

Avascular osteonecrosis of the femoral head (ONFH) is one of the causes of hip pain that clinicians need to know about. In many cases, it is a fortuitous discovery when pelvic X-rays is performed for another reason. In the other cases, pain reveals the disease. For the rheumatologist, a major part of the job is to look for a cause. An etiology can be found to ONFH in about 70% of the cases. Some of them are evident and the context give the diagnosis (corticosteroids, alcohol abuse…). However, in many cases, additional tests to imaging are required to make the causal diagnosis. In some cases, the treatment of the cause can prevent the recurrence of the disease.

Skeleton-vasculature chain reaction: a novel insight into the mystery of homeostasis

Angiogenesis and osteogenesis are coupled. However, the cellular and molecular regulation of these processes remains to be further investigated. Both tissues have recently been recognized as endocrine organs, which has stimulated research interest in the screening and functional identification of novel paracrine factors from both tissues. This review aims to elaborate on the novelty and significance of endocrine regulatory loops between bone and the vasculature. In addition, research progress related to the bone vasculature, vessel-related skeletal diseases, pathological conditions, and angiogenesis-targeted therapeutic strategies are also summarized. With respect to future perspectives, new techniques such as single-cell sequencing, which can be used to show the cellular diversity and plasticity of both tissues, are facilitating progress in this field. Moreover, extracellular vesicle-mediated nuclear acid communication deserves further investigation. In conclusion, a deeper understanding of the cellular and molecular regulation of angiogenesis and osteogenesis coupling may offer an opportunity to identify new therapeutic targets.

Factors Affecting Bone Health in Kidney Transplant Recipients: Klotho Gene Single-Nucleotide Polymorphisms and Other Clinical Features

OBJECTIVES

Posttransplant bone diseases are a major cause of morbidity in kidney transplant recipients. We investigated the relationship between klotho gene single-nucleotide polymorphisms and bone diseases after kidney transplant. We also aimed to identify possible risk factors for development of bone disease.

MATERIALS AND METHODS

The study consisted of 251 kidney transplant recipients (164 men and 87 women) with minimum follow-up of 3 years after kidney transplant. Patients with prolonged immobilization, malignancy, parathyroidectomy, glomerular filtration rates less than 30 mL/min/1.73 m², hypo- or hyperthyroidism, and treatment with drugs that affect bone metabolism were excluded. We investigated the relationship between 6 single-nucleotide polymorphisms of the klotho gene (rs480780, rs211234, rs576404, rs211235, rs9536314, and rs1207568) and development of osteoporosis, avascular bone necrosis, and persistent hyperparathyroidism.

RESULTS

Longer dialysis treatment (odds ratio, 1.13; P = .002) and rs211235 single-nucleotide polymorphism in the klotho gene (odds ratio, 9.87; P = .001 for GG genotype) were significantly associated with persistent hyperparathyroidism. A higher magnesium level was detected as a protective factor from development of persistent hyperparathyroidism (odds ratio, 0.19; P = .009). Persistent hyperparathyroidism was defined as a risk factor for development of osteopenia/osteoporosis (odds ratio, 2.76; P = .003) and avascular bone necrosis (odds ratio, 2.52; P= .03). Although the rs480780 (odds ratio, 8.73; P = .04) single-nucleotide polymorphism in the klotho gene was defined as a risk factor for development of osteopenia/osteoporosis, none of the klotho single-nucleotide polymorphisms was found to be associated with development of avascular bone necrosis.

CONCLUSIONS

Persistent hyperparathyroidism could be an important indicator for development of bone disease in kidney transplant recipients. Also, some of the klotho gene single-nucleotide polymorphisms are associated with higher risk for bone disease after kidney transplant.

Mesenchymal stromal cells for osteonecrosis

Osteonecrosis (ON) is an acquired debilitating skeletal disorder, which is caused by a multitude of traumatic and non-traumatic etiological factors. Vascular damage, mechanical stress and increased intraosseous pressure have been discussed as contributors to ON. The optimal treatment of ON remains to be determined, since the current gold standard, core decompression, is insufficiently effective. Specific properties of mesenchymal stromal cells (MSCs) provide the rationale for their assessment in advanced stages of ON: Osteoinductive potential has been demonstrated and MSC preparations of suitable quality for use as medicinal products have been developed. Here we review the scant information on the use of allogeneic or autologous MSCs in advanced ON as well as potentially supportive data from pre-clinical studies with autologous bone marrow mononuclear cells (auto BM-MNCs), which have been studied quite extensively and the presumed therapeutic effect of which was attributed to the rare MSCs contained in these cell products. Outcomes in clinical trials with MSCs and auto-BM-MNCs remain preliminary and non-definitive, at best promising, with respect to their pharmacological effect. Clearly, though, the application of any of these cell therapies was technically feasible and safe in that it was associated with low complication rates. The heterogeneity of cell type and source, study protocols, cell manufacturing, cell properties, cell doses and surgical techniques might contribute to inconsistent results.

Exploring the Risk Factors for the Misdiagnosis of Osteonecrosis of Femoral Head: A Case-Control Study

Objective

The purpose of the present study was to evaluate the present situation and risk factors for the misdiagnosis of osteonecrosis of femoral head (ONFH), providing the basis for accurate diagnosis of ONFH.

Methods

For this retrospective study, 1471 patients with ONFH were selected from the China Osteonecrosis of Femoral Head Database (CONFHD). These patients had been recruited between July 2016 and December 2018. According to whether or not they were misdiagnosed, the patients were divided into two groups, with 1168 cases (22–84 years old) included in the diagnosis group and 303 cases (21–80 years old) in the misdiagnosis group. Misdiagnosis was measured using the following criteria: (i) the patient had the same symptoms and signs, and the second diagnosis was not consistent with the initial diagnosis within 6 months; and (ii) the patient was admitted to a hospital participating in CONFHD and the previous diagnosis was inconsistent with the diagnosis given by the expert group. Comparisons of age, visual analogue scale for pain, and body mass index between the two groups were performed using a t‐test. Gender, causes of ONFH, primary diseases requiring corticosteroids, methods of corticosteroid use, corticosteroid species, type of trauma, onset side of the disease, pain side, whether symptoms are hidden, and type of imaging examination at the initial visit were compared using the χ²‐test. Years of alcohol consumption, weekly alcohol consumption, and physician title at the initial visit were compared using a Mann–Whitney U‐test. Furthermore, the statistically significant factors were evaluated using multiple regression analysis to investigate the risk factors of misdiagnosis.

Results

A total of 303 patients (20.6%) were misdiagnosed: 118 cases were misdiagnosed as lumbar disc herniation, 86 cases as hip synovitis, 48 cases as hip osteoarthritis, 32 cases as rheumatoid arthritis, 11 cases as piriformis syndrome, 5 cases as sciatica, and 3 cases as soft‐tissue injury. Whether symptoms are hidden (P = 0.038, odds ratio [OR] = 1.546, 95% confidence interval [CI] = 1.025–2.332), physician title at the initial visit (P < 0.001, OR = 3.324, 95% CI = 1.850–5.972), X‐ray examination (P < 0.001, OR = 4.742, 95% CI = 3.159–7.118), corticosteroids (P < 0.001, OR = 0.295, 95% CI = 0.163–0.534), alcohol (P < 0.001, OR = 0.305, 95% CI = 0.171–0.546), and magnetic resonance imaging (MRI) examination (P = 0.042, OR = 0.649, 95% CI = 0.427–0.985) were each found to be associated with misdiagnosis.

Conclusion

Osteonecrosis of the femoral head is easily misdiagnosed as lumbar disc herniation, hip synovitis, hip osteoarthritis, and rheumatoid arthritis. Patient history of corticosteroid use or alcohol abuse and MRI examination at the initial diagnosis may be protective factors for misdiagnosis. Hidden symptoms, physician title at the initial visit (as attending doctor or resident doctor), and only X‐ray examination at the initial diagnosis may be risk factors for misdiagnosis.

Avascular Necrosis with Cystic Changes in the Triquetrum after Trauma in Combination with Heavy Smoking and Local Corticosteroid Injections

The triquetrum is rarely affected by avascular necrosis compared with other carpal bones. We report a case of avascular necrosis of the triquetrum in a 50-year-old patient, with a history of wrist trauma, local corticosteroid injections, and heavy smoking. She presented with severe wrist pain and signs of cystic changes and avascular necrosis determined by magnetic resonance imaging. She was effectively treated with a proximal row carpectomy. We suspect that the combination of the injury in combination with local corticosteroids and smoking may have led to the necrosis.

Bone-Specific Drugs and Osteonecrosis of Sites Other Than the Jaw: A Nationwide Cohort Study

Bone-specific drugs (BSDs) increase the risk of osteonecrosis of the jaw (ONJ), but whether they increase the risk of osteonecrosis at other sites is not known. Two studies, a cohort study and a case-control study, were conducted using registry data on everyone who was residing in Sweden on December 31, 2005, and who was 50 years of age or older at the time (n = 3,523,912). In the cohort study, individuals prescribed a BSD during the period 2006-2017 (n = 217,387) were 1:1 matched with nonusers on birth year, sex, hip fracture status, and Swedish or foreign origin. In the case-control study, individuals diagnosed with osteonecrosis during 2006-2017 (n = 12,614) were 1:1 matched with individuals without a diagnosis of osteonecrosis on birth year, sex, and Swedish or foreign background. In the cohort study, osteonecrosis was diagnosed in 983 BSD users and 214 nonusers (adjusted hazard ratio [aHR] 4.02; 95% CI, 3.32-4.87), during a mean treatment time of 2.8 years. A similar association was observed in a subcohort where all individuals diagnosed with cancer (HR 4.82; 95% CI, 2.52-9.22). The greatest difference in incidence between BSD users and nonusers was observed in patients with a femoral neck fracture that was not treated with total hip arthroplasty or hemiarthroplasty (incidence rate difference, 77.8 cases per 10,000 person-years, p < .05). The risk of osteonecrosis was higher in users of denosumab (HR 1.93; 95% CI, 1.33-2.79) and users of zoledronic acid (HR 1.95; 95% CI, 1.31-2.91) than in users of other BSDs. The increased risk of osteonecrosis decreased after the end of therapy (p < .001 for time trend). The results were confirmed in the case-control study. In summary, use of BSDs, especially more potent BSDs, is associated with increased risk of osteonecrosis of sites other than the jaw. This increased risk decreases after the final dose of BSD. © 2020 American Society for Bone and Mineral Research.

Selective Chemonucleolysis With Condoliase in Cynomolgus Monkeys

Selective chemonucleolytic effects of condoliase, a glycosaminoglycan degrading enzyme, was investigated histopathologically in cynomolgus monkeys. Condoliase was administered once into the lumber intervertebral disc (IVD), and as a comparative control, chymopapain, a proteolytic enzyme, was administered in a similar manner. Histopathological changes of the IVD and the adjacent vertebral body (VB) were examined at 1 to 26 weeks after administration. Major changes induced by condoliase in the IVD were degenerative and necrotic changes in the nucleus pulposus, annulus fibrosus, cartilaginous endplate (CEP), and epiphyseal growth plate (EGP); focal disappearance of the EGP; and neovascularization and ossification of the CEP. Decreased/necrosis of bone marrow cells with new bone formation was observed in the VB. Cellular regeneration in the IVD was observed as a recovery changes on and after week 4. The changes in the IVD and VB subsided at week 26. Chymopapain induced qualitatively similar but more widely extended changes. The degrees of the changes in the IVD and VB were more severe than those of condoliase, and the changes were exacerbated even at week 26. These results indicated that histopathological changes caused by condoliase were less severe and more selective than those by chymopapain.

Short-Term Outcome and MRI Changes in Three Adult Patients with Sickle Cell Disease and Aseptic Osteonecrosis after Treatment with Hyperbaric Oxygen Therapy: A Preliminary Report

Background

Musculoskeletal manifestations are common in sickle cell disease (SCD). Vaso-occlusive crisis can manifest acutely as joint and bone pain, osteomyelitis and/or arthritis. It can also lead to chronic bone aches, bone deformities, degenerative arthritis, pathological fractures, and osteoporosis. Hyperbaric oxygen (HBO) therapy is a mode of treatment in which the patient is exposed to very high arterial and tissue oxygen pressure, during multiple sessions. It has been used as primary or adjunctive therapy for a variety of medical disorders, including necrotizing infection and sickle cell crisis.

Case Report

In this case series, 3 patients with SCD and avascular necrosis were treated with 15–40 sessions of HBO and were assessed 6–12 months by MRI after treatment. They showed different clinical outcomes and MRI changes.

Conclusion

We concluded that HBO can result in some subjective improvement, especially in early stages. Further studies on severe cases are needed.

Review/overview of pain in sickle cell disease

Sickle cell disease (SCD) is a highly complex inherited disorder of hemoglobin structure. Although the molecular lesion is a single-point mutation, the sickle gene is pleiotropic in nature causing multiple phenotypic expressions that constitute the various complications of the disease. Its manifestations could be acute, chronic, nociceptive, neuropathic that could occur singly or in various combinations. Pain continues to be the major factor of SCD phenotypic complications and the most common cause of admissions to the Emergency Department and/or the hospital. Although progress has been made in understanding the pathophysiology of SCD as well as in developing curative therapies such as hematopoietic stem cell transplantation and gene therapy, effective pain management continues to lag behind. Palliative therapies continue to be the major approach to the management of SCD and its complications. The advent of hydroxyurea made partial success in preventing the frequency of vaso-occlusive crises and l-glutamine awaits post-trial confirmation of benefits. The search for additional pharmacotherapeutic agents that could be used singly or in combination with hydroxyurea and/or l-glutamine awaits their dawn hopefully in the near future. The purpose of this review is to describe the various manifestations of SCD, their pathophysiology and their current management. Recent impressive advances in understanding the pathophysiology of pain promise the determination of agents that could replace or minimize the use of opioids.

Blood Flow in the Scaphoid Is Improved by Focused Extracorporeal Shock Wave Therapy

BACKGROUND

Extracorporeal shock wave therapy (ESWT) has shown benefits in patients with nonunion or delayed bone healing, pseudarthrosis, and avascular necrosis of bone. Until now, these effects were explained by the release of growth factors, activation of cells, and microfractures occurring after ESWT. Microcirculation is an important factor in bone healing and may be compromised in fractured scaphoids because its blood supply comes from the distal end. Due to this perfusion pattern, the scaphoid bone is prone to nonunion after fracture. The ability of ESWT to enhance microcirculation parameters in soft tissue was of interest to determine if it improves microcirculation in the scaphoid.

QUESTIONS/PURPOSES

(1) Does capillary blood flow increase after a single session of ESWT in the scaphoid? (2) Do oxygen saturation in the bone and postcapillary venous filling pressure increase after a single session of ESWT in the scaphoid?

METHODS

ESWT (0.3 mJ/mm, 8Hz, 1000 impulses) was applied to the intact scaphoid of 20 volunteers who were without wrist pain and without any important metabolic disorders. Mean age was 43 ± 14 years, 12 men and eight women (40% of total). Volunteers were recruited from January 2017 to May 2017. No anesthetic was given before application of ESWT. An innovative probe designed for measurements in bone by compressing soft tissue and combining laser-Doppler flowmetry and spectrophotometry was used to noninvasively measure parameters of microcirculation in the scaphoid. Blood flow, oxygenation, and venous filling pressure were assessed before and at 1, 2, 3, 5, 10, 15, 20, 25, and 30 minutes after ESWT application. Room temperature, humidity, ambient light and measuring sequences were kept consistent. A paired t-test was performed to compare experimental data with baseline (p < 0.05 taken as significant).

RESULTS

At baseline, capillary blood flow of the bone was 108 ± 46 arbitrary units (AUs) (86 to 130). After treatment with ESWT, it was 129 ± 44 AUs (106 to 150; p = 0.011, percentage change of 19 %) at 1 minute, 138 ± 46 AUs (116 to 160; p = 0.002, percentage change of 28%) at 2 minutes, 146 ± 54 AUs (121 to 171; p = 0.002, percentage change of 35%) at 3 minutes and 150 ± 52 AUs (126 to 174; p < 0.001, percentage change of 39%) at 5 minutes. It remained elevated until the end of the measuring period at 30 minutes after treatment at 141 ± 42 AUs (121 to 161; p = 0.002) versus baseline). Oxygen saturation and postcapillary venous filling pressure in bone showed no change, with the numbers available.

CONCLUSIONS

A single session of ESWT increased capillary blood flow in the scaphoid during measuring time of 30 minutes. Bone oxygenation and postcapillary venous filling pressure, however, did not change. Because increased oxygenation is needed for improved bone healing, it remains unclear if a sole increase in capillary blood flow can have clinical benefits. As the measuring period was limited to only 30 minutes, bone oxygenation and postcapillary filling pressure may subsequently show change only after the measuring-period ended.

CLINICAL RELEVANCE

Further studies need to evaluate if increased capillary blood flow can be sustained for longer periods and if bone oxygenation and postcapillary venous filling pressure remain unchanged even after prolonged or repetitive ESWT applications. Moreover, clinical studies must validate if increased microcirculation has a positive impact on bone healing and to determine if ESWT can be therapeutically useful on scaphoid fractures and nonunions.

Risk of Venous Thromboembolic Events in Patients with Osteonecrosis of the Femoral Head Undergoing Primary Hip Arthroplasty

Previous data have shown patients with osteonecrosis of the femoral head (ONFH) have increased lifelong risk of unprovoked venous thromboembolic events (VTE) as compared with the general population, according to sharing common pathological mechanism of endothelial dysfunction. However, whether the risk of VTE increases in those ONFH patients undergoing major hip replacement surgery remains unclear. This is a retrospective nationwide Asian population-based study. From 1997 to 2013, a total of 12,232 ONFH patients receiving partial or total hip replacement for the first time and revision surgeries were retrospectively selected from Taiwan Health Insurance surgical files. By 1:1 matching on age, sex, surgical types, and socioeconomic status, 12,232 subjects without ONFH undergoing similar hip surgery were selected as non-ONFH group. The incidence and risk of post-surgery VTE, including deep venous thrombosis (DVT) and pulmonary embolism (PE), were compared between the ONFH and non-ONFH groups. Results showed that 53.8% of ONFH patients were male and the median age was 61.9 years old. During the mean follow-up period of 6.4 years, the incidences of VTE (1.4% vs. 1.2%), DVT (1.1% vs. 0.9%), and PE (0.4% vs. 0.4%) were slightly but insignificantly higher in the ONFH than in the non-ONFH group undergoing the same types of major hip replacement surgery (all p-values > 0.250). Concordantly, we found no evidence that the risk of VTE was increased in the ONFH patients as compared with the non-ONFH counterparts (adjusted HR 1.14; 95% CI 0.91–1.42; p = 0.262). There were also no increased risks for DVT and PE in the ONFH subgroups stratified by comorbidities, drug exposure to pain-killer or steroid, and follow-up duration after surgery, either. In conclusion, hip arthroplasty in Asian patients with ONFH is associated with similar rates of VTE as compared to patients with non-ONFH diagnoses.

Treatment for avascular necrosis of bone in people with sickle cell disease

BACKGROUND

Avascular necrosis of bone is a frequent and severe complication of sickle cell disease and its treatment is not standardised. This is an update of a previously published Cochrane Review.

OBJECTIVES

To determine the impact of any surgical procedure compared with other surgical interventions or non-surgical procedures, on avascular necrosis of bone in people with sickle cell disease in terms of efficacy and safety.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register, comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. Additional trials were sought from both ongoing trial registries and the reference lists of papers identified by the search strategy. Date of the most recent search of the Group's Haemoglobinopathies Trials Register: 17 September 2019.

SELECTION CRITERIA

Randomized clinical trials comparing specific therapies for avascular necrosis of bone in people with sickle cell disease.

DATA COLLECTION AND ANALYSIS

Each author independently extracted data and assessed trial quality. The quality of the evidence was assessed using GRADE. Given only one trial was identified, meta-analyses were not possible.

MAIN RESULTS

One trial (46 participants) was eligible for inclusion. After randomization eight participants were withdrawn, mainly because they declined to participate in the trial. Data were analysed for 38 participants at the end of the trial. After a mean follow-up of three years, hip core decompression and physical therapy did not show clinical improvement when compared with physical therapy alone using the score from the original trial (an improvement of 18.1 points for those treated with intervention therapy versus an improvement of 15.7 points with control therapy). We are very uncertain whether there is any difference between groups regarding major complications (hip pain, risk ratio 0.95 (95% confidence interval 0.56 to 1.60; vaso-occlusive crises, risk ratio 1.14 (95% confidence interval 0.72 to 1.80; very low quality of evidence); and acute chest syndrome, risk ratio 1.06 (95% confidence interval 0.44 to 2.56; very low quality of evidence)). This trial did not report results on mortality or quality of life.

AUTHORS' CONCLUSIONS

We found no evidence that adding hip core decompression to physical therapy achieves clinical improvement in people with sickle cell disease with avascular necrosis of bone compared to physical therapy alone. However, we highlight that our conclusion is based on one trial with high attrition rates. Further randomized controlled trials are necessary to evaluate the role of hip-core depression for this clinical condition. Endpoints should focus on participants' subjective experience (e.g. quality of life and pain) as well as more objective 'time-to-event' measures (e.g. mortality, survival, hip longevity). The availability of participants to allow adequate trial power will be a key consideration for endpoint choice.