Low Rate of AVN and Complications in Unstable SCFE With Epiphyseal-metaphyseal Discontinuity After Treatment With a Modified Dunn Procedure.

BACKGROUND: The risk of developing avascular necrosis (AVN) in the setting of an unstable slipped capital femoral epiphysis (SCFE) that is undergoing treatment with the modified Dunn procedure is not well understood. In addition, since the Loder classification of unstable is reportedly different than actual intraoperatively observed instability (that is, discontinuity between the femoral head epiphysis and proximal femoral metaphysis), the overall risk of developing AVN, as well as the potential complications of treatment of these patients with the modified Dunn procedure, are unknown. QUESTIONS/PURPOSES: To evaluate the modified Dunn procedure for the treatment of patients with epiphyseal-metaphyseal discontinuity, we asked: (1) What was the survivorship free from AVN at 10 years? (2) What was the survivorship free from subsequent surgery and/or complications at 10 years? (3) What were the clinical and patient-reported outcome scores? METHODS: In a retrospective analysis, we identified 159 patients (159 hips) treated with a modified Dunn procedure for SCFE between 1998 and 2020, of whom 97% (155 of 159) had documentation about intraoperatively observed epiphyseal-metaphyseal stability. Of those, 37% (58 of 155) of patients were documented to have intraoperatively observed epiphyseal-metaphyseal discontinuity and were considered eligible for inclusion, whereas 63% (97 of 155) had documented epiphyseal-metaphyseal stability and were excluded. No patients were lost to follow-up before the 2-year minimum. All patients were assessed for survival, but 7% (4 of 58) did not fill out our outcomes score questionnaire. This resulted in 93% (54 of 58) of patients who were available for outcome score assessment. Additionally, 50% (29 of 58) of patients had not been seen within the last 5 years; they are included, but we note that there is uncertainty about their status. The median (range) age at surgery was 13 years (10 to 16), and the sex ratio was 60% (35 of 58) male and 40% (23 of 58) female patients. Sixty-four percent (37 of 58) of patients were classified as acute-on-chronic, and 17% (10 of 58) of patients were classified as acute. Forty-seven percent (27 of 58) of patients presented with severe slips and 43% (25 of 58) of patients with moderate slips based on radiographic classification. All patients underwent surgical hip dislocation with the modified Dunn procedure to correct the slip deformity and provide stabilization. Complications and reoperations were assessed from a review of electronic medical records, and a Kaplan-Meier estimator was used to estimate survivorship free from complications and reoperations at 10 years. Clinical examination results and questionnaire responses were evaluated at minimum 2-year follow-up. RESULTS: Kaplan-Meier survivorship free from AVN was 93% (95% CI 87% to 100%) at 10 years. Survivorship free from any reoperation was 75% (95% CI 64% to 88%) at 10 years. In addition, survivorship free from complications, defined as development of AVN, reoperation, or a Sink Grade II complication or higher, was 57% (95% CI 45% to 73%) at 10 years. The median (range) Merle D'Aubigne Postel score was 18 (14 to 18) for the patients who did not develop AVN, and 12 (6 to 16) for the four patients who developed AVN (p < 0.001). The median modified Harris hip score was 100 (74 to 100) in the non-AVN cohort and 65 (37 to 82) in the AVN cohort (p = 0.001). Median HOOS total score was 95 (50 to 100) in the non-AVN cohort and 53 (40 to 82) in the AVN cohort (p = 0.002). CONCLUSION: Although the modified Dunn procedure is technically challenging, this study shows that in experienced hands, patients with who have demonstrated epiphyseal-metaphyseal discontinuity can be treated with a low risk of AVN and subsequent surgery. Referral of these patients to specialists who have substantial expertise in this procedure is recommended to improve patient outcomes. Prospective, long-term observational studies will help us identify these high-risk patients preoperatively and determine the long-term success of this procedure. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Hip microinstability and its association with femoroacetabular impingement: A scoping review.

Introduction: Hip microinstability has become a recognized cause of non-arthritic hip pain and disability in young patients. However, its pathophysiology remains unclear. We want to (1) present an overview of the evidence of hip microinstability and of its association with femoroacetabular impingement (FAI), (2) map out the type of evidence available, and (3) make recommendations for future research. Methods: A deductive analysis and extraction method was used to extract information. In addition, diagnostic accuracy statistics were extracted or calculated. Results: Of the 2,808 identified records, 123 were eligible for inclusion. Different definitions for microinstability exist. A standardized terminology and clear diagnostic criteria are lacking. FAI and microinstability may be associated and may aggravate each other. Conservative treatment strategies for FAI and microinstability are similar. The reported prevalence of microinstability in combination with FAI ranges from 21% to 42% in adults undergoing hip arthroscopy or magnetic resonance arthrography (MRA) of the hip. Conclusion: Hip microinstability and FAI may be associated, occur together, or exacerbate each other. To better address this topic, a standardized terminology for microinstability is essential. Achieving consensus on physical examination and diagnosis is also necessary. Initial efforts to establish uniform diagnostic criteria have been made, but further work is needed. Specifically, randomized controlled trials are required to evaluate the effectiveness of training programmes aimed at reducing symptoms in individuals with microinstability, with or without FAI. Such studies will enable clinicians to manage microinstability with greater confidence within this context.

Femoral head decentration on hip MRI: comparison between imaging planes, methods of contrast administration, and hip deformities.

OBJECTIVES: To compare the prevalence of femoral head decentration (FHD) on different MR imaging planes in patients undergoing direct/indirect hip MR arthrography (MRA) with asymptomatic controls and to evaluate its association with osseous deformities. METHODS: IRB-approved retrospective single-center study of symptomatic hips undergoing direct or indirect hip MRA at 3 T. Asymptomatic participants underwent non-contrast hip MRI at 3 T. FHD was defined as a continuous fluid layer between the acetabulum and femoral head and assessed on axial, sagittal and radial images. The association of intra-articular/intra-venous contrast agents and the prevalence of FHD was evaluated. The association of FHD with osseous deformities and joint damage was assessed using multiple logistic regression analysis. RESULTS: Three-hundred ninety-four patients (447 hips, mean age 31 ± 9 years, 247 females) were included and compared to 43 asymptomatic controls (43 hips, mean age 31 ± 6 years, 26 females). FHD was most prevalent on radial images and more frequent in symptomatic hips (30% versus 2%, p < 0.001). FHD prevalence was not associated with the presence/absence of intra-articular contrast agents (30% versus 22%, OR = 1.5 (95% CI 0.9-2.5), p = 0.125). FHD was associated with hip dysplasia (OR = 6.1 (3.3-11.1), p < 0.001), excessive femoral torsion (OR = 3.0 (1.3-6.8), p = 0.010), and severe cartilage damage (OR = 3.6 (2.0-6.7), p < 0.001). CONCLUSION: While rare in asymptomatic patients, femoral head decentration in symptomatic patients is associated with osseous deformities predisposing to hip instability, as well as with extensive cartilage damage. CRITICAL RELEVANCE STATEMENT: Decentration of the femoral head on radial MRA may be interpreted as a sign of hip instability in symptomatic hips without extensive cartilage defects. Its presence could unmask hip instability and yield promise in surgical decision-making. KEY POINTS: The best method of identifying femoral head decentration is radial MRI. The presence/absence of intra-articular contrast is not associated with femoral head decentration. Femoral head decentration is associated with hip deformities predisposing to hip instability.

Metallosis-Induced Warm Antibody Auto-Immune Hemolytic Anemia After Bilateral, Large-Diameter Metal-on-Metal Total Hip Arthroplasty With Complete Remission After Revision.

The use of metal-on-metal bearing couples in total hip arthroplasty can lead to an increased release of metal ions, particularly cobalt and chromium over time. This can lead to local and systemic metallosis, which has cytotoxic, genotoxic, and immunotoxic effects and can cause a host of secondary disorders. We describe the case of a 37-year-old female patient that was diagnosed with warm-antibody autoimmune hemolytic anemia (WAIHA) one and a half years after bilateral large-diameter head metal-on-metal total hip arthroplasty. For 11 years, it was refractory to all therapy, including splenectomy and rituximab, requiring long-term oral prednisone for disease control. Ultimately, systemic metallosis and periprosthetic joint infection were diagnosed, requiring explantation of the prostheses. By the sixth week postoperatively, she experienced complete spontaneous remission of her WAIHA. In conclusion, WAIHA can be associated with systemic metallosis in patients with metal-on-metal prosthetic joint replacements. Both hematologists and orthopedic surgeons should be aware of this.

How Strong Is the Ligamentum Teres of the Hip? A Biomechanical Analysis.

BACKGROUND: Intraarticular hip pain represents a substantial clinical challenge, with recent studies implicating lesions in the ligamentum teres as potential contributors. Even more so, damage to the ligamentum teres is particularly prevalent among young patients undergoing joint-preserving interventions. Although several studies have investigated the biomechanical attributes of the ligamentum teres, inconsistencies in reported findings and reliance on cadaveric or animal models have raised concerns regarding the extrapolation of results to clinical practice. Furthermore, there is a lack of research examining ligamentum teres biomechanics specifically within the relevant patient cohort-individuals who benefit from joint-preserving surgical interventions. QUESTIONS/PURPOSES: We sought (1) to determine the biomechanical properties (ultimate load to failure, tensile strength, stiffness, and elastic modulus) of fresh-frozen ligaments from patients undergoing surgical hip dislocation, and (2) to identify patient-specific factors that are associated with them. METHODS: This was an institutional review board-approved study on intraoperatively harvested ligamentum teres from 74 consecutive patients undergoing surgical hip dislocation for joint preservation (August 2021 to September 2022). After the exclusion of patients with previous surgery, posttraumatic deformities, avascular necrosis, slipped capital femoral epiphysis, and Perthes disease, 31 ligaments from 31 patients were analyzed. The mean age of the study group was 27 ± 8 years, and 61% (19) of participants were male. The main indication for surgery was femoroacetabular impingement. Standardized AP pelvic and axial radiographs and CT scans were performed in all patients for better radiological description of the population and to identify associated radiological factors. The ligament was thoroughly transected at its origin on the fossa acetabuli and at the insertion area on the fovea capitis and stored at -20°C until utilization. Specimens were mounted to a materials testing machine via custom clamps that minimized slippage and the likelihood of failure at the clamp. Force-displacement and stress-strain curves were generated. Ultimate failure load (N), tensile strength (MPa), stiffness (N/mm), and elastic modulus (MPa) were determined. Using a multivariate regression analysis and a subgroup analysis, we tested demographic, degenerative, and radiographic factors as potential associated factors. RESULTS: The ligamentum teres demonstrated an ultimate load to failure of 126 ± 92 N, and the tensile strength was 1 ± 1 MPa. The ligaments exhibited a stiffness of 24 ± 15 N/mm and an elastic modulus of 7 ± 5 MPa. After controlling for potential confounding variables like age, fossa/fovea degeneration, and acetabular/femoral morphologies, we found that female sex was an independent factor for higher tensile strength, stiffness, and elastic modulus. Excessive femoral version was independently associated with lower load to failure (HR 122 [95% CI 47 to 197]) and stiffness (HR 15 [95% CI 2 to 27]). Damage to the acetabular fossa was associated with reduced load to failure (HR -93 [95% CI -159 to -27]). CONCLUSION: Overall, the ligamentum teres is a relatively weak ligament. Sex, degeneration, and excessive femoral version are influencing factors on strength of the ligamentum teres. The ligamentum teres exhibits lower strength compared with other joint-stabilizing ligaments, which calls into question its overall contribution to hip stability. CLINICAL RELEVANCE: Young patients undergoing hip-preserving surgery are the population at risk for ligamentum teres lesions. Baseline values for load to failure, tensile strength, elastic modulus, and stiffness are needed to better understand those lesions in this cohort of interest.

Comparison of Two Modern Survival Prediction Tools, SORG-MLA and METSSS, in Patients With Symptomatic Long-bone Metastases Who Underwent Local Treatment With Surgery Followed by Radiotherapy and With Radiotherapy Alone.

BACKGROUND: Survival estimation for patients with symptomatic skeletal metastases ideally should be made before a type of local treatment has already been determined. Currently available survival prediction tools, however, were generated using data from patients treated either operatively or with local radiation alone, raising concerns about whether they would generalize well to all patients presenting for assessment. The Skeletal Oncology Research Group machine-learning algorithm (SORG-MLA), trained with institution-based data of surgically treated patients, and the Metastases location, Elderly, Tumor primary, Sex, Sickness/comorbidity, and Site of radiotherapy model (METSSS), trained with registry-based data of patients treated with radiotherapy alone, are two of the most recently developed survival prediction models, but they have not been tested on patients whose local treatment strategy is not yet decided. QUESTIONS/PURPOSES: (1) Which of these two survival prediction models performed better in a mixed cohort made up both of patients who received local treatment with surgery followed by radiotherapy and who had radiation alone for symptomatic bone metastases? (2) Which model performed better among patients whose local treatment consisted of only palliative radiotherapy? (3) Are laboratory values used by SORG-MLA, which are not included in METSSS, independently associated with survival after controlling for predictions made by METSSS? METHODS: Between 2010 and 2018, we provided local treatment for 2113 adult patients with skeletal metastases in the extremities at an urban tertiary referral academic medical center using one of two strategies: (1) surgery followed by postoperative radiotherapy or (2) palliative radiotherapy alone. Every patient's survivorship status was ascertained either by their medical records or the national death registry from the Taiwanese National Health Insurance Administration. After applying a priori designated exclusion criteria, 91% (1920) were analyzed here. Among them, 48% (920) of the patients were female, and the median (IQR) age was 62 years (53 to 70 years). Lung was the most common primary tumor site (41% [782]), and 59% (1128) of patients had other skeletal metastases in addition to the treated lesion(s). In general, the indications for surgery were the presence of a complete pathologic fracture or an impending pathologic fracture, defined as having a Mirels score of ≥ 9, in patients with an American Society of Anesthesiologists (ASA) classification of less than or equal to IV and who were considered fit for surgery. The indications for radiotherapy were relief of pain, local tumor control, prevention of skeletal-related events, and any combination of the above. In all, 84% (1610) of the patients received palliative radiotherapy alone as local treatment for the target lesion(s), and 16% (310) underwent surgery followed by postoperative radiotherapy. Neither METSSS nor SORG-MLA was used at the point of care to aid clinical decision-making during the treatment period. Survival was retrospectively estimated by these two models to test their potential for providing survival probabilities. We first compared SORG to METSSS in the entire population. Then, we repeated the comparison in patients who received local treatment with palliative radiation alone. We assessed model performance by area under the receiver operating characteristic curve (AUROC), calibration analysis, Brier score, and decision curve analysis (DCA). The AUROC measures discrimination, which is the ability to distinguish patients with the event of interest (such as death at a particular time point) from those without. AUROC typically ranges from 0.5 to 1.0, with 0.5 indicating random guessing and 1.0 a perfect prediction, and in general, an AUROC of ≥ 0.7 indicates adequate discrimination for clinical use. Calibration refers to the agreement between the predicted outcomes (in this case, survival probabilities) and the actual outcomes, with a perfect calibration curve having an intercept of 0 and a slope of 1. A positive intercept indicates that the actual survival is generally underestimated by the prediction model, and a negative intercept suggests the opposite (overestimation). When comparing models, an intercept closer to 0 typically indicates better calibration. Calibration can also be summarized as log(O:E), the logarithm scale of the ratio of observed (O) to expected (E) survivors. A log(O:E) > 0 signals an underestimation (the observed survival is greater than the predicted survival); and a log(O:E) < 0 indicates the opposite (the observed survival is lower than the predicted survival). A model with a log(O:E) closer to 0 is generally considered better calibrated. The Brier score is the mean squared difference between the model predictions and the observed outcomes, and it ranges from 0 (best prediction) to 1 (worst prediction). The Brier score captures both discrimination and calibration, and it is considered a measure of overall model performance. In Brier score analysis, the "null model" assigns a predicted probability equal to the prevalence of the outcome and represents a model that adds no new information. A prediction model should achieve a Brier score at least lower than the null-model Brier score to be considered as useful. The DCA was developed as a method to determine whether using a model to inform treatment decisions would do more good than harm. It plots the net benefit of making decisions based on the model's predictions across all possible risk thresholds (or cost-to-benefit ratios) in relation to the two default strategies of treating all or no patients. The care provider can decide on an acceptable risk threshold for the proposed treatment in an individual and assess the corresponding net benefit to determine whether consulting with the model is superior to adopting the default strategies. Finally, we examined whether laboratory data, which were not included in the METSSS model, would have been independently associated with survival after controlling for the METSSS model's predictions by using the multivariable logistic and Cox proportional hazards regression analyses. RESULTS: Between the two models, only SORG-MLA achieved adequate discrimination (an AUROC of > 0.7) in the entire cohort (of patients treated operatively or with radiation alone) and in the subgroup of patients treated with palliative radiotherapy alone. SORG-MLA outperformed METSSS by a wide margin on discrimination, calibration, and Brier score analyses in not only the entire cohort but also the subgroup of patients whose local treatment consisted of radiotherapy alone. In both the entire cohort and the subgroup, DCA demonstrated that SORG-MLA provided more net benefit compared with the two default strategies (of treating all or no patients) and compared with METSSS when risk thresholds ranged from 0.2 to 0.9 at both 90 days and 1 year, indicating that using SORG-MLA as a decision-making aid was beneficial when a patient's individualized risk threshold for opting for treatment was 0.2 to 0.9. Higher albumin, lower alkaline phosphatase, lower calcium, higher hemoglobin, lower international normalized ratio, higher lymphocytes, lower neutrophils, lower neutrophil-to-lymphocyte ratio, lower platelet-to-lymphocyte ratio, higher sodium, and lower white blood cells were independently associated with better 1-year and overall survival after adjusting for the predictions made by METSSS. CONCLUSION: Based on these discoveries, clinicians might choose to consult SORG-MLA instead of METSSS for survival estimation in patients with long-bone metastases presenting for evaluation of local treatment. Basing a treatment decision on the predictions of SORG-MLA could be beneficial when a patient's individualized risk threshold for opting to undergo a particular treatment strategy ranged from 0.2 to 0.9. Future studies might investigate relevant laboratory items when constructing or refining a survival estimation model because these data demonstrated prognostic value independent of the predictions of the METSSS model, and future studies might also seek to keep these models up to date using data from diverse, contemporary patients undergoing both modern operative and nonoperative treatments. LEVEL OF EVIDENCE: Level III, diagnostic study.

Comparison of Classically and Machine Learning Generated Survival Prediction Models for Patients With Spinal Metastasis - A meta-Analysis of Two Recently Developed Algorithms.

STUDY DESIGN: A systemic review and a meta-analysis. We also provided a retrospective cohort for validation in this study. OBJECTIVE: (1) Using a meta-analysis to determine the pooled discriminatory ability of The Skeletal Oncology Research Group (SORG) classical algorithm (CA) and machine learning algorithms (MLA); and (2) test the hypothesis that SORG-CA has less variability in performance than SORG-MLA in non-American validation cohorts as SORG-CA does not incorporates regional-specific variables such as body mass index as input. METHODS: After data extraction from the included studies, logit-transformation was applied for extracted AUCs for further analysis. The discriminatory abilities of both algorithms were directly compared by their logit (AUC)s. Further subgroup analysis by region (America vs non-America) was also conducted by comparing the corresponding logit (AUC). RESULTS: The pooled logit (AUC)s of 90-day SORG-CA was .82 (95% confidence interval [CI], .53-.11), 1-year SORG-CA was 1.11 (95% CI, .74-1.48), 90-day SORG-MLA was 1.36 (95% CI, 1.09-1.63), and 1-year SORG-MLA was 1.57 (95% CI, 1.17-1.98). All the algorithms performed better in United States than in Taiwan (P < .001). The performance of SORG-CA was less influenced by a non-American cohort than SORG-MLA. CONCLUSION: These observations might highlight the importance of incorporating region-specific variables into existing models to make them generalizable to racially or geographically distinct regions.

Drop in survivorship 13 years after AMIC procedures in aligned knees: A long-term follow-up.

PURPOSE: Autologous matrix-induced chondrogenesis (AMIC) showed promising short-term results comparable to microfracture. This study aims to assess the 19-year outcomes of AMIC, addressing the lack of long-term data. METHODS: Retrospective cohort of 34 knees treated with AMIC underwent a 19-year follow-up. The primary outcome was AMIC survival, considering total knee arthroplasty as a failure event. Survival analysis for factors that were associated with longer survival of the AMIC was also performed. Clinical and radiological outcome scores were analysed for the AMIC group. RESULTS: Twenty-three knees were available for follow-up analysis. Of these, 14 (61%) underwent revision surgery for total knee arthroplasty (TKA). The mean time was 13.3 ± 2.5 years (range: 9-17 years). Secondary outcomes showed that increased age at surgery (hazard ratio [HR]: 1.05; p = 0.021) and larger defect size (HR: 1.95; p = 0.018) were risk factors for failure. Concomitant proximal tibial osteotomy (HR: 0.22; p = 0.019) was associated with longer survival. The remaining nine knees (39%) were analysed as a single group. The mean clinical score at follow-up of 18.6 ± 0.9 SD years was 79.5 ± 19.7 SD for the Lysholm score, 1.8 ± 1.5 SD for the visual analog scale score, 74.2 ± 22.4 SD for the KOOS score and a median of 3 (range: 3-4) for the Tegner activity scale. CONCLUSIONS: The mean survival time of 13.3 years indicates the durability of AMIC in properly aligned knees. Nonetheless, despite a 61% conversion to TKA, the knees that persisted until the 19-year follow-up remained stable, underscoring the procedure's longevity and consistent clinical outcomes. LEVEL OF EVIDENCE: Level IV.

Modified Dunn Procedure for Open Reduction of Chronic Slipped Capital Femoral Epiphysis.

Background: Abnormal femoral head anatomy following moderate-to-severe slipped capital femoral epiphysis (SCFE) can lead to femoroacetabular impingement and premature osteoarthritis4-10. Surgical correction at the deformity site through capital reorientation has the potential to fully ameliorate this but has traditionally been associated with high rates of osteonecrosis11-15. The modified Dunn procedure has the potential to restore anatomy in hips with SCFE while protecting the blood supply to the femoral head. Description: A surgical dislocation of the hip is performed according to the technique described by Ganz et al.16. The remaining posterosuperior portion of the greater trochanter is trimmed to the level of the femoral neck by subperiosteal bone removal performed in an inside-out manner. The periosteum of the femoral neck is gradually elevated. The resulting soft-tissue flap, consisting of the retinaculum and external rotators, holds the blood vessels supplying the epiphysis. The femoral epiphysis is pinned in situ (in unstable cases) with threaded Kirschner wires, the ligamentum teres is transected, and the femoral head is dislocated. With the femoral neck exposed, the epiphysis is gradually mobilized from the metaphysis, allowing exposure of the residual femoral neck and inspection of any posteroinferior callus. To avoid tension on the retinacular vessels during reduction of the epiphysis, the posterior neck callus is completely excised. The remaining physis is removed with use of a burr while holding the epiphysis stable. The epiphysis is gently reduced onto the femoral neck, avoiding tension on the retinacular vessels. If tension is noted, the femoral neck is rechecked for residual callus, which is excised. If no callus is found, the neck may be carefully shortened in order to minimize tension. Epiphyseal fixation is achieved with use of a 3-mm fully threaded wire inserted antegrade through the fovea to the lateral cortex below the greater trochanter. A second wire is inserted retrograde under fluoroscopy. After reducing the hip, the capsule is closed and the greater trochanter is reattached with use of 3.5-mm cortical screws. Alternatives: Alternatives include nonoperative treatment, in situ fixation (e.g., pinning or screw fixation), gentle closed reduction with pinning, and triplanar trochanteric osteotomy (e.g., Imhauser or Southwick osteotomies). Rationale: In situ pinning of mild-to-moderate, stable SCFE yields good long-term results with low rates of osteonecrosis9. Treatment of higher-grade SCFE without reduction aims to avoid osteonecrosis and assumes that the proximal femoral deformity will remodel; however, the head-neck offset will remain abnormal, risking impingement and early-onset osteoarthritis5,8. The procedure described in the present article allows anatomic reduction of the epiphysis with a low risk of osteonecrosis. Surgical dislocation of the hip16 with development of an extended retinacular soft-tissue flap17 provides extensive subperiosteal exposure of the circumferential femoral neck and preserves the vulnerable blood supply to the epiphysis18. The Dunn subcapital realignment procedure15 with callus removal and slip angle correction allows anatomic restoration of the proximal femur. Expected Outcomes: Reported results of various centers performing the procedure vary greatly with regard to the number of hips treated and the follow-up time. Most studies have been retrospective and have lacked a control group. The reported risk of osteonecrosis ranges from 0% to 25.9%19, with the wide range most likely because of the challenging nature of the technique, the low number of cases per surgeon, and the long learning curve associated with the procedure. In centers with extensive experience in pediatric hip-preserving surgery, the reported rate of osteonecrosis is low3. Studies with mid to long-term follow-up have shown no conversion to total hip arthroplasty3,20,21, but residual deformities can persist, and subsequent surgery is possible. Important Tips: Extensive experience in surgical hip dislocation and retinacular flap development is a prerequisite for successful outcomes and low rates of osteonecrosis.Sufficient callus and physeal remnant resections are needed to avoid tension on the retinacular vessels during epiphyseal reduction.The skin incision should be centered over the greater trochanterThe Gibson interval must be carefully prepared for adequate release and to avoid injury.Tension on the periosteal flap should be avoided to prevent stress on the retinacular vessels. Acronyms and Abbreviations: AP = anteroposteriorAVN = avascular necrosis (i.e., osteonecrosis)CI = confidence intervalCT = computed tomographyK-wire = Kirschner wireMRI = magnetic resonance imagingOA = osteoarthritisSHD = surgical hip dislocationTHA = total hip arthroplastyVTE = venous thromboembolism.

Proceedings of the Think Tank for Osteosarcoma Medical Advisory Board.

A "Think Tank for Osteosarcoma" medical advisory board meeting was held in Santa Monica, CA, USA on February 2-3, 2024. The goal was to develop a strategic approach to prevent recurrence of osteosarcoma. Osteosarcoma metabolism and the genomic instability of osteosarcoma, immunotherapy for osteosarcoma, CAR-T cell therapy, DeltaRex-G tumor-targeted gene therapy, repurposed drugs, alternative medicines, and personalized medicine were discussed. Only DeltaRex-G was voted on. The conclusions were the following: No intervention has been demonstrated to improve survival in a clinical trial. Additionally, the consensus (10/12 in favor) was that DeltaRex-G without immunotherapy may be administered for up to one year. Phase 2/3 randomized studies of DeltaRex-G should be performed to determine whether the incidence of recurrence could be reduced in high-risk individuals. Furthermore, a personalized approach using drugs with minimal toxicity could be attempted with the acknowledgement that there are no efficacy data to base this on. Repurposed drugs and alternative therapies should be tested in mouse models of osteosarcoma. Moreover, unmodified IL-2 primed Gamma Delta (NK) cell therapy may be used to prevent recurrence. Lastly, rapid development of CAR-T cell therapy is recommended, and an institute dedicated to the study of osteosarcoma is needed.

Factors associated with skeletal-related events in patients with bone metastatic melanoma: A retrospective study of 481 patients.

OBJECTIVES: Metastatic bone disease is estimated to develop in up to 17% of patients with melanoma, compromising skeleton integrity resulting in skeletal-related events (SREs), which impair quality of life and reduce survival. The objective of the study was to investigate (1) the proportion of melanoma patients developing SREs following diagnosis of bone metastasis and (2) the predictors for SREs in this patient cohort. METHODS: Four hundred and eighty-one patients with bone metastatic melanoma from two tertiary centers in the United States from 2008 to 2018 were included. The primary outcome was 90-day and 1-year occurrence of a SRE, including pathological fractures of bones, cord compression, hypercalcemia, radiotherapy, and surgery. Fine-Gray regression analysis was performed for overall SREs and pathological fracture, with death as a competing risk. RESULTS: By 1-year, 52% (258/481) of patients experienced SREs, and 28% (137/481) had a pathological fracture. At 90-day, lytic lesions, bone pain, elevated calcium and absolute lymphocyte, and decreased albumin and hemoglobin were associated with higher SRE risk. The same factors, except for decreased hemoglobin, were shown to predict development of SREs at 1-year. CONCLUSION: The high incidence of SREs and pathological fractures warrants vigilance using the identified factors in this study and preventative measures during clinical oncological care.

Patient-Reported Outcomes After Intramedullary Nailing of Oncologic Impending or Pathologic Fractures With Carbon Fiber or Titanium Implant.

INTRODUCTION: Despite the benefits of intramedullary nailing (IMN) of impending or pathologic fractures in oncologic patients, literature on patient-reported outcomes (PROs) is scarce in patients treated with carbon fiber (CF) nails. Our study compared postoperative PROs after IMN with CF or titanium implants. METHODS: We conducted a retrospective propensity score-matched cohort study of patients treated at our institution with CF or titanium nails for impending or pathologic fractures from metastatic bone disease. Patient-Reported Outcomes Measurement Information System (PROMIS) Global Health Short Form (SF) Physical, Mental, and Physical Function 10a scores were collected. Pain was assessed using visual analog scale (VAS). Absolute and differential scores were compared between groups. RESULTS: We included 207 patients, 51 treated with CF and 156 with titanium nails. One month postoperatively, patients had a one-point decrease in the pain VAS score while PROMIS scores did not improve. At 3 months, PROMIS SF Physical and SF 10a scores improved from preoperative values. Six months postoperatively, median PROMIS SF Physical, SF Mental, and SF 10a scores were higher than preoperative scores. Absolute and differential PROMIS and pain VAS scores were similar between groups at the 6-month and 1-year marks. CONCLUSION: Patient-reported outcomes were similar after intramedullary nailing with either CF or titanium implants.

Remineralization Rate of Lytic Lesions of the Spine in Multiple Myeloma Patients Undergoing Radiation Therapy.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: In general, Multiple Myeloma (MM) patients are treated with systemic therapy including chemotherapy. Radiation therapy can have an important supportive role in the palliative management of MM-related osteolytic lesions. Our study aims to investigate the degree of radiation-induced remineralization in MM patients to gain a better understanding of its potential impact on bone mineral density and, consequently, fracture prevention. Our primary outcome measure was percent change in bone mineral density measured in Hounsfield Units (Δ% HU) between pre- and post-radiation measurements, compared to non-targeted vertebrae. METHODS: We included 119 patients with MM who underwent radiotherapy of the spine between January 2010 and June 2021 and who had a CT scan of the spine at baseline and between 3-24 months after radiation. A linear mixed effect model tested any differences in remineralization rate per month (ßdifference) between targeted and non-targeted vertebrae. RESULTS: Analyses of CT scans yielded 565 unique vertebrae (366 targeted and 199 non-targeted vertebrae). In both targeted and non-targeted vertebrae, there was an increase in bone density per month (ßoverall = .04; P = .002) with the largest effect being between 9-18 months post-radiation. Radiation did not cause a greater increase in bone density per month compared to non-targeted vertebrae (ßdifference = .67; P = .118). CONCLUSION: Our results demonstrate that following radiation, bone density increased over time for both targeted and non-targeted vertebrae. However, no conclusive evidence was found that targeted vertebrae have a higher remineralization rate than non-targeted vertebrae in patients with MM.

Quality of life in chordoma survivors: results from the Chordoma Foundation Survivorship Survey.

OBJECTIVE: Chordomas are rare malignant bone tumors whose location in the skull base or spine, invasive surgical treatment, and accompanying adjuvant radiotherapy may all lead patients to experience poor quality of life (QOL). Limited research has been conducted on specific demographic and clinical factors associated with decreased QOL in chordoma survivors. Thus, the aim of the present study was to investigate several potential variables and their impact on specific QOL domains in these patients as well the frequencies of specific QOL challenges within these domains. METHODS: The Chordoma Foundation (CF) Survivorship Survey was electronically distributed to chordoma survivors subscribed to the CF Chordoma Connections forum. Survey questions assessed QOL in three domains: physical, emotional/cognitive, and social. The degree of impairment was assessed by grouping the participants into high- and low-challenge groups designated by having ≥ 5 or < 5 symptoms or challenges within a given QOL domain. Bivariate analysis of demographic and clinical characteristics between these groups was conducted using Fisher's exact test and the Mann-Whitney U-test. RESULTS: A total of 665 chordoma survivors at least partially completed the survey. On bivariate analysis, female sex was significantly associated with increased odds of significant emotional (p = 0.001) and social (p = 0.019) QOL burden. Younger survivors (age < 65 years) were significantly more likely to experience significant physical (p < 0.0001), emotional (p < 0.0001), and social (p < 0.0001) QOL burden. Skull base chordoma survivors had significantly higher emotional/cognitive QOL burden than spinal chordoma survivors (p = 0.022), while the converse was true for social QOL challenges (p = 0.0048). Survivors currently in treatment were significantly more likely to experience significant physical QOL challenges compared with survivors who completed their treatment > 10 years ago (p = 0.0074). Fear of cancer recurrence (FCR) was the most commonly reported emotional/cognitive QOL challenge (49.6%). Only 41% of the participants reported having their needs met for their physical QOL challenges as well as 25% for emotional/cognitive and 18% for social. CONCLUSIONS: The authors' findings suggest that younger survivors, female survivors, and survivors currently undergoing treatment for chordoma are at high risk for adverse QOL outcomes. Additionally, although nearly half of the participants reported a FCR, very few reported having adequate emotional/cognitive care. These findings may be useful in identifying specific groups of chordoma survivors vulnerable to QOL challenges and bring to light the need to expand care to meet the QOL needs for these patients.

Predictive Modeling for Spinal Metastatic Disease.

Spinal metastasis is exceedingly common in patients with cancer and its prevalence is expected to increase. Surgical management of symptomatic spinal metastasis is indicated for pain relief, preservation or restoration of neurologic function, and mechanical stability. The overall prognosis is a major driver of treatment decisions; however, clinicians' ability to accurately predict survival is limited. In this narrative review, we first discuss the NOMS decision framework used to guide decision making in the treatment of patients with spinal metastasis. Given that decision making hinges on prognosis, multiple scoring systems have been developed over the last three decades to predict survival in patients with spinal metastasis; these systems have largely been developed using expert opinions or regression modeling. Although these tools have provided significant advances in our ability to predict prognosis, their utility is limited by the relative lack of patient-specific survival probability. Machine learning models have been developed in recent years to close this gap. Employing a greater number of features compared to models developed with conventional statistics, machine learning algorithms have been reported to predict 30-day, 6-week, 90-day, and 1-year mortality in spinal metastatic disease with excellent discrimination. These models are well calibrated and have been externally validated with domestic and international independent cohorts. Despite hypothesized and realized limitations, the role of machine learning methodology in predicting outcomes in spinal metastatic disease is likely to grow.

Chondrosarcoma of the Mobile Spine: An Update on Patients Treated at a Single Institution.

STUDY DESIGN: Retrospective study. OBJECTIVE: The objective is to report the clinical data for patients treated with mobile spine chondrosarcoma. SUMMARY OF BACKGROUND DATA: Chondrosarcoma of the mobile spine is a rare and challenging entity. A handful of case series have been published that report the clinical results of treatment, largely influenced by chondrosarcoma of the appendicular skeleton and pelvis. The clinical results of patients treated for chondrosarcoma of the mobile spine from our institution were published over ten years ago and this represents and update since that publication. METHODS: Inclusion criteria were adults patients treated for chondrosarcoma of the mobile spine at Massachusetts General Hospital between 2007-2020. Patients with large sacral tumors extending into the lumbar spine were excluded. Further, we excluded patients with metastatic chondrosarcoma undergoing palliative decompressions for neurologic instability or instrumented procedures for biomechanical instability. Therefore, only patients undergoing definitive surgery at the primary site of disease in the mobile spine were included. RESULTS: Twenty-four patients were included for review in this series. Seventeen of the 24 patients had their tumors excised with negative (R0) margins. Three of these 17 patients (18%) were dead of disease at final follow-up. There were two patients with R1 resections and five patients with R2 resections. Three of the 7 patients (43%) with positive margins were dead of disease at final follow-up. A Cox proportional hazard analysis indicated total radiation dose was a significant covariate (HR 1.18, 95% CI 1.01 - 1.39, P=0.03). CONCLUSION: We found higher percentages of overall survival with R0 tumor resection and lower histologic grade whereas development of metastatic disease was closely associated with local recurrence and poor survival. Despite the improvements in treatment paradigms, it is sobering that our findings largely mirror those of previous work considering patients treated between 1984 and 2006.

Influence of acetabular and femoral morphology on pelvic tilt.

Aims: The aim of this study was to investigate whether anterior pelvic plane-pelvic tilt (APP-PT) is associated with distinct hip pathomorphologies. We asked: is there a difference in APP-PT between young symptomatic patients being evaluated for joint preservation surgery and an asymptomatic control group? Does APP-PT vary among distinct acetabular and femoral pathomorphologies? And does APP-PT differ in symptomatic hips based on demographic factors? Methods: This was an institutional review board-approved, single-centre, retrospective, case-control, comparative study, which included 388 symptomatic hips in 357 patients who presented to our tertiary centre for joint preservation between January 2011 and December 2015. Their mean age was 26 years (SD 2; 23 to 29) and 50% were female. They were allocated to 12 different morphological subgroups. The study group was compared with a control group of 20 asymptomatic hips in 20 patients. APP-PT was assessed in all patients based on supine anteroposterior pelvic radiographs using validated HipRecon software. Values in the two groups were compared using an independent-samples t-test. Multiple regression analysis was performed to examine the influences of diagnoses and demographic factors on APP-PT. The minimal clinically important difference (MCID) for APP-PT was defined as > 1 SD. Results: There were no significant differences in APP-PT between the control group and the overall group (1.1° (SD 3.0°; -4.9° to 5.9°) vs 1.8° (SD 3.4°; -6.9° to 13.2°); p = 0.323). Acetabular retroversion and overcoverage groups showed higher mean APP-PTs compared with the control group (p = 0.001 and p = 0.014) and were the only diagnoses with a significant influence on APP-PT in the stepwise multiple regression analysis. All differences were below the MCID. The age, sex, height, weight, and BMI showed no influence on APP-PT. Conclusion: APP-PT showed no radiologically significant variation across different pathomorphologies of the hip in patients being assessed for joint-preserving surgery.

Opportunistic CT for Prediction of Adverse Postoperative Events in Patients with Spinal Metastases.

The purpose of this study was to assess the value of body composition measures obtained from opportunistic abdominal computed tomography (CT) in order to predict hospital length of stay (LOS), 30-day postoperative complications, and reoperations in patients undergoing surgery for spinal metastases. 196 patients underwent CT of the abdomen within three months of surgery for spinal metastases. Automated body composition segmentation and quantifications of the cross-sectional areas (CSA) of abdominal visceral and subcutaneous adipose tissue and abdominal skeletal muscle was performed. From this, 31% (61) of patients had postoperative complications within 30 days, and 16% (31) of patients underwent reoperation. Lower muscle CSA was associated with increased postoperative complications within 30 days (OR [95% CI] = 0.99 [0.98-0.99], p = 0.03). Through multivariate analysis, it was found that lower muscle CSA was also associated with an increased postoperative complication rate after controlling for the albumin, ASIA score, previous systemic therapy, and thoracic metastases (OR [95% CI] = 0.99 [0.98-0.99], p = 0.047). LOS and reoperations were not associated with any body composition measures. Low muscle mass may serve as a biomarker for the prediction of complications in patients with spinal metastases. The routine assessment of muscle mass on opportunistic CTs may help to predict outcomes in these patients.