Female patients have greater improvement in pain symptoms and physical activity after fasciotomy for treatment of chronic exertional compartment syndrome of the lower leg.

PURPOSE: The purpose of this study was to identify sex differences in postoperative outcomes and return-to-sport rates after fasciotomy for treatment of chronic exertional compartment syndrome (CECS) of the lower leg. It was hypothesised that male CECS patients would have a higher rate of return to sport than female CECS patients. METHODS: A retrospective cohort study was conducted involving patients who underwent primary fasciotomy of one to four leg compartments for treatment of CECS at a single centre from 2010 to 2020. Each affected leg was treated as a separate subject. Postoperative outcomes included CECS pain frequency and severity, return to sport and Tegner activity level. Multivariable regression was used to determine if sex was an independent predictor of outcomes after adjusting for demographic and clinical covariates. p < 0.05 were considered significant. RESULTS: Eighty-one legs (44 M, 37 F) of 47 unique patients (34 of whom had bilateral symptoms) were included with a mean follow-up time of 51.5 ± 31.4 months. Male subjects were older (p < 0.001) and had higher body mass index (p < 0.001) compared to female subjects. Most subjects (84.0%) underwent two- or four-compartment fasciotomies. Female sex was found to be predictive of lower overall postoperative pain severity (p = 0.007), higher odds of return to sport (p = 0.04) and higher postoperative Tegner score (p = 0.005). However, female sex was not predictive of postoperative pain frequency, odds of reoperation or odds of return to sport to at least the presymptomatic level (all p < 0.05). CONCLUSION: Female sex is independently predictive of reduced overall pain severity, higher odds of return to sport and higher postoperative improvement in Tegner score following fasciotomy for treatment of lower-limb CECS. LEVEL OF EVIDENCE: III.

Paresthesia Is Predictive of Symptom Recurrence After Fasciotomy for Exertional Compartment Syndrome of the Leg.

BACKGROUND: Exertional compartment syndrome (ECS) is an underdiagnosed cause of lower extremity pain among athletes. The condition can be managed operatively by fasciotomy to relieve excess compartment pressure. However, symptom recurrence rates after fasciotomy are considerable, ranging from 3% to 17%. HYPOTHESIS: Leg paresthesia and its distribution during ECS episodes would be a significant predictor of outcomes after fasciotomy. STUDY DESIGN: Retrospective cohort study. LEVEL OF EVIDENCE: Level 4. METHODS: We conducted a retrospective chart review of patients who underwent fasciotomy for ECS at our center from 2010 to 2020 (institutional review board no. 21-00107). We measured postoperative outcomes including pain frequency and severity, Tegner activity level, and return to sport. Significant predictors of outcomes were identified using multivariable linear and logistic regression. P values <0.05 were considered significant. RESULTS: A total of 78 legs (from 42 male and 36 female participants) were included in the study with average follow-up of 52 months (range, 3-126 months); 33 participants (42.3%) presented with paresthesia. Paresthesia was an independent predictor of worse outcomes, including more severe pain at rest (P = 0.05) and with daily activity (P = 0.04), reduced postoperative improvement in Tegner scores (P = 0.04), and lower odds of return to sport (P = 0.05). Those with paresthesia symptoms in the tibial nerve distribution had worse outcomes than those without paresthesia in terms of preoperative-to-present improvement in pain frequency (P < 0.01), pain severity at rest (P < 0.01) and with daily activity (P = 0.04), and return to sport (P = 0.04). CONCLUSION: ECS patients who present with paresthesia have worse pain and activity outcomes after first-time fasciotomy, but prognosis is worst among those with tibial nerve paresthesia. CLINICAL RELEVANCE: Paresthesia among ECS patients is broadly predictive of more severe recurrent leg pain, reduced activity level, and decreased odds of return to sport after fasciotomy.

Clinical Presentation and Outcomes of Sacral Stress Fractures in Athletes: A Case Series of 13 Patients.

BACKGROUND: Sacral stress fractures are a rare cause of low back pain in athletes. Given the low incidence of these fractures, there is a scarcity of data on symptomatology, risk factors, and clinical outcomes. HYPOTHESIS: Patients diagnosed with sacral stress fractures would be athletes presenting with low back pain. STUDY DESIGN: Case series of 13 patients with sacral stress fractures. LEVEL OF EVIDENCE: Level 4. METHODS: We conducted a retrospective review of medical records to identify patients diagnosed with sacral stress fractures at a single academic institution. Fractures were diagnosed on noncontrast T2-weighted magnetic resonance imaging scans and categorized using the Bakker classification system. Subjects were administered an electronic survey that asked about (1) the onset, time course, and location of pain and other symptoms; (2) time to treatment and treatment modalities pursued; (3) sports performance and time to return to sport; and (4) risk factors for stress fractures. RESULTS: Of 18 eligible patients, 13 (72.2%) completed the survey with mean follow-up of 49.6 months (range, 1-144 months). Mean age was 28.0 years (range, 18-52 years); 9 patients (69.2%) were female, of whom 7 (77.8%) were premenopausal. The most common fracture type was Bakker type B (8 patients; 61.5%). Most patients presented with acute lumbosacral back pain in the setting of running/jogging activities. All patients underwent nonoperative treatment for an average of 3.8 months (range, 0-8 months) and three-quarters reported pain resolution at last follow-up. Rate of return to sport was 83.3%, but most patients reported ongoing deficits in running performance. CONCLUSION: Sacral stress fractures commonly present as acute lumbosacral back pain provoked by running sports. While the pain associated with these fractures prevents most athletes from participating in sports, nonoperative management appears to be an effective treatment modality with a high rate of return to sport.

Loss of Notch signaling in skeletal stem cells enhances bone formation with aging.

Skeletal stem and progenitor cells (SSPCs) perform bone maintenance and repair. With age, they produce fewer osteoblasts and more adipocytes leading to a loss of skeletal integrity. The molecular mechanisms that underlie this detrimental transformation are largely unknown. Single-cell RNA sequencing revealed that Notch signaling becomes elevated in SSPCs during aging. To examine the role of increased Notch activity, we deleted Nicastrin, an essential Notch pathway component, in SSPCs in vivo. Middle-aged conditional knockout mice displayed elevated SSPC osteo-lineage gene expression, increased trabecular bone mass, reduced bone marrow adiposity, and enhanced bone repair. Thus, Notch regulates SSPC cell fate decisions, and moderating Notch signaling ameliorates the skeletal aging phenotype, increasing bone mass even beyond that of young mice. Finally, we identified the transcription factor Ebf3 as a downstream mediator of Notch signaling in SSPCs that is dysregulated with aging, highlighting it as a promising therapeutic target to rejuvenate the aged skeleton.

Inflammatory conversion of quiescent osteoblasts by metastatic breast cancer cells through pERK1/2 aggravates cancer-induced bone destruction.

Disruption of bone homeostasis caused by metastatic osteolytic breast cancer cells increases inflammatory osteolysis and decreases bone formation, thereby predisposing patients to pathological fracture and cancer growth. Alteration of osteoblast function induces skeletal diseases due to the disruption of bone homeostasis. We observed increased activation of pERK1/2 in osteolytic breast cancer cells and osteoblasts in human pathological specimens with aggressive osteolytic breast cancer metastases. We confirmed that osteolytic breast cancers with high expression of pERK1/2 disrupt bone homeostasis via osteoblastic ERK1/2 activation at the bone-breast cancer interface. The process of inflammatory osteolysis modulates ERK1/2 activation in osteoblasts and breast cancer cells through dominant-negative MEK1 expression and constitutively active MEK1 expression to promote cancer growth within bone. Trametinib, an FDA-approved MEK inhibitor, not only reduced breast cancer-induced bone destruction but also dramatically reduced cancer growth in bone by inhibiting the inflammatory skeletal microenvironment. Taken together, these findings suggest that ERK1/2 activation in both breast cancer cells and osteoblasts is required for osteolytic breast cancer-induced inflammatory osteolysis and that ERK1/2 pathway inhibitors may represent a promising adjuvant therapy for patients with aggressive osteolytic breast cancers by altering the shared cancer and bone microenvironment.

Erratum to accuracy of wearable heart rate monitors in cardiac rehabilitation.

[This corrects the article DOI: 10.21037/cdt.2019.04.08.].

Accuracy of wearable heart rate monitors in cardiac rehabilitation.

BACKGROUND: To assess the accuracy of four wearable heart rate (HR) monitors in patients with established cardiovascular disease enrolled in phase II or III cardiac rehabilitation (CR). METHODS: Eighty adult patients enrolled in phase II or III CR were monitored during a CR session that included exercise on a treadmill and/or stationary cycle. Participants underwent HR monitoring with standard ECG limb leads, an electrocardiographic (ECG) chest strap monitor (Polar H7), and two randomly assigned wrist-worn HR monitors (Apple Watch, Fitbit Blaze, Garmin Forerunner 235, TomTom Spark Cardio), one on each wrist. HR was recorded at rest and at 3, 5, and 7 minutes of steady-state exercise on the treadmill and stationary cycle. RESULTS: Across all exercise conditions, the chest strap monitor (Polar H7) had the best agreement with ECG (rc=0.99) followed by the Apple Watch (rc=0.80), Fitbit Blaze (rc=0.78), TomTom Spark (rc=0.76) and Garmin Forerunner (rc=0.52). There was variability in accuracy under different exercise conditions. On the treadmill, only the Fitbit Blaze performed well (rc=0.76), while on the stationary cycle, Apple Watch (rc=0.89) and TomTom Spark (rc=0.85) were most accurate. CONCLUSIONS: In cardiac patients, the accuracy of wearable, optically based HR monitors varies, and none of those tested was as accurate as an electrode-containing chest monitor. This observation has implications for in-home CR, as electrode-containing chest monitors should be used when accurate HR measurement is imperative.