Comparison of rerupture rates after operative and nonoperative management of Achilles tendon rupture in older populations: Systematic review and meta-analysis.

Background: This systematic review and meta-analysis investigated the treatment for Achilles tendon rupture (ATR) associated with the lowest risk of rerupture in older patients. Methods: Five databases were searched through September 2022 for studies published in the past 10 years analyzing operative and nonoperative ATR treatment. Studies were categorized as "nonelderly" if they reported only on patients aged 18-60 years. Studies that included at least 1 patient older than age 70 were categorized as "elderly inclusive." Of 212 studies identified, 28 were eligible for inclusion. Of 2965 patients, 1165 were treated operatively: 429 (37%) from elderly-inclusive studies and 736 (63%) from nonelderly studies. Of the 1800 nonoperative patients 553 (31%) were from nonelderly studies and 1247 (69%) were from elderly-inclusive studies. Results: For nonoperative treatment, the rate of rerupture was higher in nonelderly studies (83/1000 cases, 95% CI = 58, 113) than in elderly-inclusive studies (38/1000 cases, 95% CI = 22, 58; P<.001). For operative treatment no difference was found in the rate of rerupture between nonelderly studies (7/1000 cases, 95% CI = 0, 21) and elderly-inclusive studies (12/1000 cases, 95% CI = 0, 35; P<.78). Overall, operative treatment was associated with a rerupture rate of 1.5% (95% CI: 1.0%, 2.8%) (P<.001), which was lower than the 5% rate reported by other studies for nonoperative management (P<.001). Conclusion: Older patients may benefit more than younger patients from nonoperative treatment of ATR. More studies are needed to determine the age at which rerupture rates decrease among nonoperatively treated patients. Level of Evidence: 3.

Barriers to Entry: Socioeconomic Discrepancies Between Unmatched First-Time Applicants and Reapplicants in the Field of Orthopaedic Surgery.

INTRODUCTION: Orthopaedic surgery remains a competitive surgical subspecialty with more applicants than spots each year. As a result, numerous students fail to match into these competitive positions each year with a growing number of reapplicants in consecutive application cycles. We sought to understand the socioeconomic factors at play between this growing reapplicant pool compared with first-time applicants to better understand potential discrepancies between these groups. Our hypothesis is that reapplicants would have higher socioeconomic status and have less underrepresented minority representation compared with successful first-time applicants. METHODS: A retrospective review of deidentified individual orthopaedic surgery applicant data from the American Association of Medical Colleges was reviewed from 2011 to 2021. Individual demographic and application data as well as self-reported socioeconomic and parental data were analyzed using descriptive and advanced statistics. RESULTS: Of the 12,112 applicants included in this data set, 77% were first-time applicants (61% versus 17% successfully entered into an orthopaedic surgery residency vs versus unmatched, respectively), whereas 22% were reapplicants. In successful first-time applicants, 12% identified as underrepresented minorities in medicine. The proportion of underrepresented minorities was significantly higher among unmatched first-time applicants (20%) and reapplicants (25%) ( P < 0.001). Reapplicants (mean = $83,364) and unmatched first-time applicants (mean = $80,174) had less medical school debt compared with first time applicants (mean = $101,663) ( P < 0.001). More than 21% of reapplicants were found to have parents in healthcare fields, whereas only 16% of successful first-time applicants and 15% of unsuccessful first-applicants had parents in health care ( P < 0.001). CONCLUSIONS: Reapplicants to orthopaedic surgery residency have less educational debt and are more likely to have parental figures in a healthcare field compared with first-time applicants. This suggests the discrepancies in socioeconomic status between reapplicants and first-time applicants and the importance of providing resources for reapplicants.

Predicting Risk of 30-day Postoperative Morbidity Using the Pathologic Fracture Mortality Index.

INTRODUCTION: The purpose of this study was to evaluate the ability of the Pathologic Fracture Mortality Index (PFMI) to predict the risk of 30-day morbidity after pathologic fracture fixation and compare its efficacy with those of the American Society of Anesthesiologists (ASA) physical status, modified Charlson Comorbidity Index (mCCI), and modified frailty index (mFI-5). METHODS: Cohorts of 1,723 patients in the American College of Surgeons National Surgical Quality Improvement Program database from 2005 to 2020 and 159 patients from a tertiary cancer referral center who underwent fixation for impending or completed pathologic fractures of long bones were retrospectively analyzed. National Surgical Quality Improvement Program morbidity variables were categorized into medical, surgical, utilization, and all-cause. PFMI, ASA, mCCI, and mFI-5 scores were calculated for each patient. Area under the curve (AUC) was used to compare efficacies. RESULTS: AUCs predicting all-cause morbidity were 0.62, 0.54, and 0.56 for the PFMI, ASA, and mFI-5, respectively. The PFMI outperformed the ASA and mFI-5 in predicting all-cause ( P < 0.01), medical ( P = 0.01), and utilization ( P < 0.01) morbidities. In the 2005 to 2012 subset, the PFMI outperformed the ASA, mFI-5, and mCCI in predicting all-cause ( P = 0.01), medical ( P = 0.03), and surgical ( P = 0.05) morbidities but performed similarly to utilization morbidity ( P = 0.19). In our institutional cohort, the AUC for the PFMI in morbidity stratification was 0.68. The PFMI was associated with all-cause (odds ratio [OR], 1.30; 95% confidence interval [CI], 1.12 to 1.51; P < 0.001), medical (OR, 1.19; 95% CI, 1.03 to 1.40; P = 0.046), and utilization (OR, 1.32; 95% CI, 1.14 to 1.52; P < 0.001) morbidities but not significantly associated with surgical morbidity (OR, 1.21; 95% CI, 0.98 to 1.49; P = 0.08) in this cohort. DISCUSSION: The PFMI is an advancement in postoperative morbidity risk stratification of patients with pathologic fracture from metastatic disease. LEVEL OF EVIDENCE: III.

Match Rates Among Underrepresented Minority and Female Applicants to Orthopaedic Surgery Residency Programs from 2011 to 2021: How Are We Doing?

Background: Orthopaedic surgery residency programs have traditionally had less representation of underrepresented minority (URM) and female trainees compared with other medical specialties. Widespread efforts have been implemented to increase the diversity of orthopaedic surgery residency programs; however, it is not known whether URM and female applicants are increasingly likely to match as a result. Thus, we aimed to study the independent association between URM and female applicants and matching into orthopaedic surgery over the past decade. Methods: Applicant-level data from the Electronic Residency Application Service were reviewed from 2011 to 2021 with variables including demographic variables, URM status, and matriculation to an orthopaedic surgery residency program. Multivariate logistic regression was used to identify the likelihood of matriculating into orthopaedic surgery when controlling for number of applications, top 40 medical school status, AOA status, and MD/other degree. Results: Twelve thousand one hundred eleven applicants were identified from 2011 to 2021 with a match rate of 70% overall. Two thousand fifty-six applicants (17%) were female and 1,926 (16%) classified as URM. The total number of applications increased from 1,074 in 2011 to 1,229 in 2021. The adjusted odds ratio (OR) associated with matching among all applicants decreased from 0.75 in 2011 to 0.64 in 2021, p < 0.001, and the OR of non-URM male and female applicants also decreased (female: 0.79-0.69, p < 0.001; male: 0.78-0.65, p < 0.001). The OR of URM male applicants did not change significantly (0.57-0.55, p = 0.60). The OR for URM female applicants, however, increased significantly from 0.46 to 0.61, p < 0.001. Over the entire time frame, the odds of matching were significantly lower for URM applicants compared with non-URM applicants (both male and female). Conclusions: Overall, the adjusted odds ratio of matching into orthopaedic surgery among female URM applicants has increased over the past decade, indicating successful efforts to improve the diversity of orthopaedic surgery training programs. The odds of URM male applicants have remained relatively constant, and the odds of URM male and female applicants were significantly lower than all non-URM applicants. Level of Evidence: III.

Bone Metastases in Patients with Leiomyosarcoma: A Retrospective Analysis of Survival and Surgical Management.

Background: Leiomyosarcomas (LMS) are malignancies with smooth muscle differentiation. Metastasis to the bone is not uncommon. The literature on the clinical course and management of such metastases is limited. Our study describes the clinical course of LMS to the bone, including survival rates, prognostic factors, and surgical management. Methods: We retrospectively reviewed 396 LMS patients presenting at an academic center between 1995 and 2020. We included LMS patients diagnosed with bone metastases and excluded patients with primary LMS of bone. We evaluated survival time with the Kaplan-Meier survival method and used Cox's proportional hazards regression analysis to determine factors associated with survival. Results: Forty-five patients with LMS (11%) had bone metastases. The most common LMS subtypes with bone metastases were uterine (N = 18, 40%) and retroperitoneal (N = 15, 33%). Bone metastasis was not an independent predictor of mortality by Cox regression analysis (HR 1.0, 95% CI: 0.67-1.5). Patients more frequently metastasized to the axial (N = 29, 64%) than to the appendicular (N = 5, 11%) skeleton. Bone was the first site of metastasis in 13 patients (29%). Patients presented with bone metastases at a median of 32.7 months (IQR: 5.2, 62.6) after initial LMS diagnosis. Twelve patients (27%) sustained a pathologic fracture. Twenty (44%) required surgical management, with 30 surgeries total. Three (15%) had a failure of reconstructive constructs. The median overall survival time was 69.7 months (IQR: 43.2, 124.5). There were no associations between the LMS subtype and survival. Pathologic fracture was an independent predictor of mortality by Cox regression analysis (HR 5.4, 95% CI: 1.8-16). Conclusion: The majority of patients with metastatic LMS to bone survive greater than 5 years and frequently require surgical intervention. Extended survival in this patient population should inform fixation and implant choice. No anatomic subtype was associated with risk for bone metastases. Pathologic fracture was associated with worse survival.

Pelvic Osteotomy in Patients With Previous Sacral-Alar-Iliac (SAI) Fixation.

INTRODUCTION: Patients with neuromuscular disease are at high risk for developing hip dysplasia and scoliosis. The purpose of this study was to investigate the technical challenges and outcomes of pelvic osteotomy in patients with prior sacral-alar-iliac (SAI) fixation. METHODS: We reviewed clinical and radiographic records of patients aged 18 years and below who underwent pelvic osteotomy after SAI fixation. We recorded technical challenges during the osteotomy, time from SAI fixation to osteotomy, type of osteotomy, migration index, and distance from the SAI screw to the acetabulum. A 2-sample Wilcoxon rank-sum test was used to assess the data. RESULTS: Nineteen patients were included. Technical challenges were defined as having greater intraoperative fluoroscopy times and noted difficult osteotomy in the operative report. The mean time from SAI fixation to pelvic osteotomy was 2.2±1.5 years. For all 12 Chiari osteotomies, the ilium could not be laterally displaced; however, medial displacement of the distal segment of the osteotomy allowed adequate coverage. All 7 Dega osteotomies were performed by cutting the cortex at the tip of the SAI screw. The screw improved proximal leverage and provided a strong buttress for bone graft. The mean migration index before pelvic osteotomy was 59±19%, and at most recent follow-up was 13±4%. Twelve patients, who had a noted complicated osteotomy, had SAI screws that were ≤1.87 cm ( P <0.01) from the acetabulum and significantly increased intraoperative fluoroscopy time (1.76 vs. 1.18 min, P <0.01). CONCLUSIONS: The presence of SAI screws may cause iliac osteotomies to be technically challenging if the tip of the SAI screw is ≤1.87 cm to the acetabulum. When initially implanting SAI screws in neuromuscular patients, surgeons should attempt to place screw tips ∼2 cm from the acetabulum in the event these patients require subsequent pelvic osteotomy. LEVEL OF EVIDENCE: Level IV.

Sacral-Alar-Iliac (SAI) Fixation in Patients With Previous Pelvic Osteotomy.

STUDY DESIGN: This was a retrospective study. OBJECTIVE: The purpose of this study was to investigate the technical challenges and outcomes of sacral-alar-iliac (SAI) fixation for scoliosis in patients who had previously undergone a pelvic osteotomy for hip dysplasia. SUMMARY OF BACKGROUND DATA: Patients with neuromuscular disease are at high risk for developing hip dislocation and scoliosis. Surgical correction of one may affect the other. METHODS: We reviewed the records of patients aged 18 years and below who underwent spinal fusion using SAI screws after having undergone a pelvic osteotomy, with ≥2-year follow-up. We recorded the SAI screw dimensions, time from osteotomy to SAI fixation, type of osteotomy, and any complications performing SAI fixation due to the pelvic osteotomy. Bivariate statistics were used to analyze the data with statistical significance defined as P -value <0.05. RESULTS: Thirty-two patients were included. The average age was 10.3±3.2 years at pelvic osteotomy and 13.5±3.4 years at SAI fixation. Most patients had cerebral palsy (87.5%) and a unilateral Dega osteotomy (78.1%). Average screw dimensions were significantly shorter on the side of the osteotomy (66 vs. 72 mm, P <0.05). SAI screw placement was technically challenging in 8 patients (25%), due to pelvic distortion from the pelvic osteotomy. The use of a curved awl helped to find the intracortical channel. No patients had complications due to the SAI screw, and there were no significant differences in pelvic obliquity and major coronal curve correction. Two patients (6.3%) had screw lucency >2 mm around the SAI screw on the side of the pelvic osteotomy but no clinical symptoms. CONCLUSIONS: SAI fixation in patients with previous pelvic osteotomy is technically challenging due to pelvic morphology and prior implants. Often, a shorter SAI screw is required on the side of the osteotomy. However, outcomes in this patient population are satisfactory, with no significant complications at a 2-year follow-up. LEVEL OF EVIDENCE: Level IV.

Sacral-Alar-Iliac (SAI) Fixation in Children With Spine Deformity: Minimum 10-Year Follow-Up.

INTRODUCTION: Sacral-alar-iliac (SAI) screws are utilized to achieve pelvic fixation in spine deformity patients. The primary purpose of this study is to investigate the long-term outcomes of pediatric patients with scoliosis treated with posterior spinal fusion and SAI fixation at 10-year clinical and radiographic follow-up. METHODS: We reviewed the clinical and radiographic records of patients aged 18 years or below treated for scoliosis with posterior spinal fusion using SAI fixation. Pelvic obliquity and the major coronal curve were determined at the preoperative visit and 6-week, 1-year, 5-year, and 10-year postoperative visits. SAI screw-specific data collected included screw dimensions, rate of screw revision, pain at the SAI screw sites, presence of lucency >2 mm around the screw, screw loosening or breaking, and deep surgical site infections. RESULTS: Ninety-seven of 151 patients (75%) were included. The average age at index surgery was 13.5±3.1 years, and the most common diagnosis was cerebral palsy (67%). The mean duration of follow-up was 11±3 years. The mean pelvic obliquity measured 20±8.0 degrees preoperatively, and 8.7±4.0 degrees at the 10-year follow-up. There were no significant difference in pelvic obliquity when comparing the 10-year follow-up visit with the 6-week postoperative follow-up. Average screw dimensions were 8.4×68.8 mm. By the 10-year follow-up, 4 patients (4%) had at least 1 SAI screw-related complication. Of these patients, 2 (2%) had pain at 1 SAI screw, 4 (4%) had lucency around the screw, and 3 (3%) had broken or loose screws. Two (2%) required SAI screw revision because of late deep wound infection, and underwent exchange with a longer screw. There were no intrapelvic protrusions, vascular, or neurological complications. CONCLUSIONS: SAI screws are a safe and effective method for pelvic fixation in children with spinal deformity. The outcomes at ≥10 years are satisfactory, with low rates of long-term complications and excellent postoperative correction and subsequent maintenance of coronal curvature and pelvic obliquity over time. LEVEL OF EVIDENCE: Level IV.

Interlocking Fixation in Fassier-Duval Rods: Performance and Success Factors.

INTRODUCTION: Pediatric patients with osteogenesis imperfecta (OI) can be treated with intramedullary Fassier-Duval rod (FDR) systems for limb deformity or recurrent fractures. Single-interlocking pins can improve epiphyseal fixation, but there is a paucity of literature examining incidence of rod migration or pin backout long-term. The purpose of this study is to quantify rates of rod migration and pin backout in OI patients treated with single-interlocking FDRs. METHODS: A retrospective chart review was performed on pediatric patients treated at a tertiary care center across a 15-year period. Inclusion criteria to select patients was: (1) Pediatric patients (below 18 y of age); (2) Patients with confirmed OI; and (3) Patients with lower extremity fractures or deformity treated with FDRs with distal interlocking pins. Age at time of surgery, rates of obturator migration and pin backout and prominence were collected. We recorded if pin tips were bent by the surgeon during the procedure. Bivariate statistics were used to analyze risk factors for pin backout and prominence. RESULTS: Twenty-four single-interlocking pin FDRs (21 tibia, 3 femur) were identified. The mean age at index surgery was 5.7±3.4 years, with the mean follow-up time of 7.2±4.7 years. Fourteen (58%) rods underwent revision surgery. Obturator proximal migration was observed in 3/24 rods (13%). No cases of obturator distal migration were observed (0/24, 0%). Mean proximal obturator migration was 2.16±1.8 cm. Revision for pin backout was observed in 10 (42%) rods and pin prominence in 11 (46%) extremities. Bending interlocking pins on at least 1 end was associated with decreased pin backout (P=0.01) and prominence (P=0.04). CONCLUSIONS: Even with distal interlocking pins, the obturator of FDRs can still migrate over time. Pin backout is a common indication for revision surgery. Bending interlocking pins can decrease rates of pin backout and prominence. LEVEL OF EVIDENCE: Level III.

In Vivo Gene Editing of Muscle Stem Cells with Adeno-Associated Viral Vectors in a Mouse Model of Duchenne Muscular Dystrophy.

Delivery of therapeutic transgenes with adeno-associated viral (AAV) vectors for treatment of myopathies has yielded encouraging results in animal models and early clinical studies. Although certain AAV serotypes efficiently target muscle fibers, transduction of the muscle stem cells, also known as satellite cells, is less studied. Here, we used a Pax7nGFP;Ai9 dual reporter mouse to quantify AAV transduction events in satellite cells. We assessed a panel of AAV serotypes for satellite cell tropism in the mdx mouse model of Duchenne muscular dystrophy and observed the highest satellite cell labeling with AAV9 following local or systemic administration. Subsequently, we used AAV9 to interrogate CRISPR/Cas9-mediated gene editing of satellite cells in the Pax7nGFP;mdx mouse. We quantified the level of gene editing using a Tn5 transposon-based method for unbiased sequencing of editing outcomes at the Dmd locus. We also found that muscle-specific promoters can drive transgene expression and gene editing in satellite cells. Lastly, to demonstrate the functionality of satellite cells edited at the Dmd locus by CRISPR in vivo, we performed a transplantation experiment and observed increased dystrophin-positive fibers in the recipient mouse. Collectively, our results confirm that satellite cells are transduced by AAV and can undergo gene editing to restore the dystrophin reading frame in the mdx mouse.

Myogenic Progenitor Cell Lineage Specification by CRISPR/Cas9-Based Transcriptional Activators.

Engineered CRISPR/Cas9-based transcriptional activators can potently and specifically activate endogenous fate-determining genes to direct differentiation of pluripotent stem cells. Here, we demonstrate that endogenous activation of the PAX7 transcription factor results in stable epigenetic remodeling and differentiates human pluripotent stem cells into skeletal myogenic progenitor cells. Compared with exogenous overexpression of PAX7 cDNA, we find that endogenous activation results in the generation of more proliferative myogenic progenitors that can maintain PAX7 expression over multiple passages in serum-free conditions while preserving the capacity for terminal myogenic differentiation. Transplantation of human myogenic progenitors derived from endogenous activation of PAX7 into immunodeficient mice resulted in a greater number of human dystrophin+ myofibers compared with exogenous PAX7 overexpression. RNA-sequencing analysis also revealed transcriptome-wide differences between myogenic progenitors generated via CRISPR-based endogenous activation of PAX7 and exogenous PAX7 cDNA overexpression. These studies demonstrate the utility of CRISPR/Cas9-based transcriptional activators for controlling cell-fate decisions.