Surgically Treated Femoral Neck Stress Fractures Are Likely to Result in Military Separation During Basic Combat Training.

BACKGROUND: Femoral neck stress fractures are a common condition affecting military service members, most noticeably during basic combat training. Previous studies have investigated the risk factors for femoral neck stress fracture development in basic trainees and outcomes associated with treatment; however, few studies have focused on operatively treated femoral neck stress fracture in the military trainee. Doing so would be important not only for the military, but also providers caring for athletes, such as distance runners, who have a heightened risk for femoral neck stress fracture development. QUESTIONS/PURPOSES: (1) What proportion of US Army trainees completing basic combat training at Fort Jackson, SC, USA, who undergo surgery for femoral neck stress fracture during basic training subsequently leave military service because of the injury? (2) What factors are related to the patient or the fracture are associated with a higher likelihood of military separation? (3) What factors on the initial MRI are associated with progression of the stress fracture extent? METHODS: A retrospective study of a longitudinally maintained database of stress injuries involving basic combat trainees from a single military post was reviewed over a 3-year period. Inclusion criteria included basic trainees undergoing surgery for a femoral neck stress fracture between January 2018 and June 2020 with a minimum of 1-year follow-up. Surgery was indicated for service members with complete and tension-sided femoral neck stress fractures and those with high risk compression-sided stress fractures, generally representing fractures involving more than 50% of the femoral neck width. Over the study period, 57 service members (51% [29 of 57] women with a mean age of 24 years) underwent surgery for a femoral neck stress fracture, and all 57 had a minimum of 1-year follow-up. Identified service members underwent independent data collection including injury and radiographic parameters based on chart and imaging review. Documented fracture line progression on repeat imaging was present in 39% of service members, with a mean fracture line progression of 55% of the femoral neck width. Service members were subdivided based upon the ability to return to military service at 1 year. Univariate analysis was performed using patient and injury variables to identify factors associated with the ability to return to military service. RESULTS: Overall, 58% (33 of 57) of service members who had a femoral neck stress fracture treated surgically underwent military separation. A higher proportion of service members who demonstrated fracture line progression leading to surgical treatment remained in the military (58% [14 of 24] versus 30% [10 of 33]; odds ratio 0.3 [95% confidence interval (CI) 0.1 to 0.9]; p = 0.03). With the numbers available, we found no other patient- or fracture-related variables associated with military separation, although we suspect we may have been underpowered on some of these comparisons, in particular gender (61% [20 of 33] of individuals separated after surgery for this injury were women compared with 38% [9 of 24] who were retained; OR 2.6 [95% CI 0.9 to 7.56]; p = 0.09). The extent of osseous edema on T1-weighted imaging in association with a hip effusion demonstrated a significant positive correlation with final fracture percentage (r = 0.62; p = 0.003). CONCLUSION: Military service members with a femoral neck stress fracture initially managed nonoperatively but with progression of the fracture line requiring surgical intervention were more likely to return to military duties and complete basic combat training, suggesting that early diagnosis of femoral neck stress fractures may be associated with better functional recovery after surgical treatment. Additionally, the extent of the osseous edema on initial MRI T1-weighted imaging sequences may help predict the final extent of femoral neck stress fractures on repeat imaging. Further investigations should incorporate patient-reported outcomes and further explore factors associated with fracture progression and the inability to return to active duty or sport. LEVEL OF EVIDENCE: Level III, therapeutic study.

Core Decompression and Bone Marrow Aspirate Concentrate in the Treatment of Femoral Head Avascular Necrosis in Pediatric Sickle Cell Disease: Can We Improve Natural History?

INTRODUCTION: Femoral head avascular necrosis (AVN) affects between 10% and 41% of children with sickle cell disease (SCD), resulting in the development of proximal femoral deformity and residual hip pain in the majority of patients without treatment. There have been multiple adult studies published on the outcomes of core decompression with and without the use of bone marrow aspirate concentrate (BMAC) injection both in idiopathic and SCD-related AVN with promising results, however, few studies have reported on outcomes in skeletally immature patients. PURPOSE: This study sought to report on a single surgeon's outcomes for core decompression with BMAC injection in pediatric patients with AVN of the femoral head secondary to underlying SCD. METHODS: A single-center, retrospective review was performed for pediatric patients undergoing core decompression with BMAC injection for femoral head AVN in patients with SCD with a minimum of 12-month follow-up. Demographic, radiographic, and clinical variable were collected. Patients were subdivided based upon presence of open femoral physes at the time of surgery. Successful treatment was defined as the ability to return to activities without limitations. RESULTS: A total of 13 patients (average age 14.1±2.8 y, 84.6% male, 6 skeletally immature and 7 skeletally mature) with 18 affected extremities were identified. Open physes were present in 50% of operative extremities. Skeletally immature patient demonstrated reconstitution of the femoral head in 78% of cases and 89% demonstrated regression of at least 1 Steinberg grade and none had progression. Skeletally immature patients were significantly more likely to return to activities (100% vs. 55.6%, P=0.023) and achieve a final Tonnis grade <2 (89% vs. 44%, P=0.046). CONCLUSION: Core decompression appears to alter the natural history of AVN in skeletally immature patients with SCD. Skeletal immaturity was a positive prognostic factor for the ability to return to activities without pain and achieve a lower Tonnis grade at final follow-up.

Primary Medial Patellofemoral Ligament Reconstruction in Military Servicemembers: Can We Reliably Restore Preinjury Function and Stability?

BACKGROUND: Medial patellofemoral ligament (MPFL) reconstruction for patellar instability is a commonly performed procedure with a reported high rate of return to preinjury activity. However, no previous study has assessed the functional outcomes of military servicemembers undergoing MPFL reconstruction. HYPOTHESIS: Primary MPFL reconstruction confers patellar stability, but with limited return to preinjury function and ability to maintain unrestricted military active duty status. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Using the Management Analysis and Reporting Tool database, we conducted a retrospective review of active duty servicemembers throughout the US Department of Defense Health System who underwent primary MPFL reconstruction between 2012 and 2015. Demographic variables were recorded as well as ability to return to impact activities-defined as running, jumping, rucking with a load >40 pounds (18 kg), and returning to airborne operations-and to remain on active duty status. The rates of recurrent instability and the need for subsequent surgeries were identified and assessed for statistical significance using uni- and multivariate analyses. Patients were evaluated for a minimum of 2 years postoperatively. RESULTS: Of the 213 patients who underwent primary MPFL reconstruction, including 34 with concomitant tibial tubercle osteotomy, 19 (8.9%) patients developed recurrent instability. The presence of bilateral patellar instability was associated with higher recurrence rate. Patients with bilateral instability comprised 47.3% of those with recurrence but only 24.9% of patients without recurrence (P = .019). Impact activity restrictions were present in 57.6% of patients (n = 121), with 86 patients (52.1%) undergoing medical separation from the military. Patients who were prescribed activity restriction before surgery were significantly more likely to have postoperative activity restrictions (64.5%; P = .019), and junior enlisted servicemembers were more likely to be medically separated from service postoperatively than higher ranking senior enlisted members or officers. CONCLUSION: Only 42.4% of US military servicemembers undergoing primary MPFL reconstruction were able to return to unrestricted impact activity after surgery. Bilateral instability negatively affected return to impact activities. Military servicemembers, particularly junior enlisted members, should be counseled on this poor prognosis for a full return to unrestricted activity postoperatively.

Magnetic Resonance Imaging of Pectoralis Major Injuries in an Active Duty Military Cohort: Mechanism Affects Tear Location.

BACKGROUND: Pectoralis major (PM) tendon tears are common injuries in athletic patient populations, where operative repair is largely recommended for maximum functional recovery. The repair varies in difficulty and technique based on the location of the tear within the muscle-tendon unit. Magnetic resonance imagining (MRI) has been reported to be sensitive and specific for identifying the tear location, but the effect of injury mechanism on tear pattern has not been previously investigated. PURPOSE: To examine PM tears in a military patient population and assess the effect of injury mechanism (weightlifting vs high-energy trauma) on the tear pattern and accuracy of MRI interpretation. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Active duty military servicemembers undergoing operative repair of PM tendon tears with corresponding preoperative MRIs from 2 medical centers were identified. Two musculoskeletal fellowship-trained radiologists reviewed imaging studies, reporting the location of the tear within the muscle-tendon unit and the severity of the tear (sternal head vs clavicular head vs both). Radiographic findings were compared against intraoperative findings. Mechanism of injury and timing from injury to imaging and surgery were assessed to determine whether they affected the accuracy of MRI interpretations. RESULTS: A total of 72 patients were included (mean ± SD age, 33.7 ± 7.0 years; 100% male). Mechanisms of injury consisted of 46 weightlifting injuries and 26 high-energy injuries. Interrater reliability was poor for tear location (kappa, 0.162; P = .003) but substantial for extent of tear (kappa, 0.637; P < .0001). MRI had a 51.3% sensitivity and 63.6% specificity for identifying complete tears. MRI had a sensitivity of 73.9% and specificity of 72.2% for avulsion injuries and sensitivity of 75% and specificity of 79.3% for musculotendinous injuries. Mechanism of injury had no effect on extent of the tear but did affect the location of the tear, with a higher rate of avulsion injuries in the high-energy mechanism cohort (81% vs 40%; P = .02). CONCLUSION: The mechanism of injury was found to significantly affect the location of tendon tears. A higher rate of avulsion injuries was found in high-energy injuries than weightlifting injuries. MRI appeared to be less sensitive and specific than previous reports for traumatic PM tendon injuries.