Predicting brace holiday eligibility in juvenile idiopathic scoliosis.

PURPOSE: The psychological effects of scoliosis bracing can be difficult, and thus clinicians sometimes recommend a brace holiday when the curve corrects to less than 25°. However, the clinical indications for taking a break from the brace before reaching maturity have yet to be described. We hypothesized there would be a relationship between brace holiday eligibility and degree of curve at presentation, change in curve magnitude while bracing, and level of bracing compliance. METHODS: A retrospective cohort study at a single institution was performed from 2016 to 2022. Objective brace compliance I-button data were collected on patients aged 3-9 years old. Patients with other etiologies besides idiopathic scoliosis before the age of 10 were excluded. Binary logistic regression was performed to determine the effect of significant variables on the likelihood of brace holiday. RESULTS: Fifty-six patients met inclusion criteria. Of these, 20 were able to get a brace holiday. Patients with higher brace compliance and larger in-brace curve correction were more likely to get a brace holiday (P = 0.015, 0.004). Patients with higher BMIs and larger curves at initial presentation were less likely to get a brace holiday (P = 0.002, 0.014). CONCLUSION: Compliant brace wearers with good in-brace correction are most likely to be eligible for a brace holiday. While some elements remain immutable, others are modifiable, such as bracing compliance. Understanding how outcomes differ between patients who do and do not take a brace holiday will be crucial to elucidating if the psychological benefit of taking a break from the brace can be justified.

Eye of the Carpenter: How Well do Orthopaedic Surgeons Estimate Angular Measurements in Derotational Osteotomies?

BACKGROUND: Femoral derotational osteotomies are used by orthopaedic surgeons to decrease version in a variety of pathologies. Intraoperatively, the goal of the surgery is to decrease the rotation of the femur to within physiological range. Surgeons generally visually estimate the angle of correction based on bone markers at the rotating cylindrical portion of the femur. This study sought first to assess the accuracy and inter-rater reliability of surgeons with respect to angle creation, and then to implement a training intervention. METHODS: A rotational femur model was constructed and tested among surgeons and nonsurgeons. Surgeons were then randomized into an experimental and control cohort with training on the model as the intervention. Subjects were asked to create target angles of 15, 30, 45, and 60 degrees using only Kirschner wires and then only bone marks for reference. Independent and paired t -tests were performed to determine variability between cohorts. RESULTS: The mean angle creation error and range of the surgeon cohort were significantly lower than those of the nonsurgeon cohort. Within the nonsurgeon cohort, the mean angle creation error and range of the wire modality were significantly lower than that of the mark modality. The mean angle creation error and range of the trained cohort were significantly lower than the untrained cohort. CONCLUSIONS: The considerable inter-subject range within the surgeon cohort highlights a need for the reinforcement of basic geometric principles within orthopaedic instruction. This model allows for immediate, accurate feedback on angle creation, and training appears to be both time and cost-effective. The physiological range allows for a level of variability between surgical outcomes without consequence. However, the more than 20 degree range determined by this study does not fall within those bounds and should be addressed. CLINICAL RELEVANCE: Moving forward, rotational estimation as a surgical skill should increase in prominence within orthopaedic instruction to maximize future joint health, and additional emphasis should be placed on fundamental spatial orientation during training.

Patellofemoral joint load and knee abduction/adduction moment are sensitive to variations in femoral version and individual muscle forces.

Torsional profiles of the lower limbs, such as femoral anteversion, can dictate gait and mobility, joint biomechanics and pain, and functional impairment. It currently remains unclear how the interactions between femoral anteversion, kinematics, and muscle activity patterns contribute to joint biomechanics and thus conditions such as knee pain. This study presents a computational modeling approach to investigating the interactions between femoral anteversion, muscle forces, and knee joint loads. We employed an optimal control approach to produce actuator and muscle-driven simulations of the stance phase of gait for femoral anteversion angles ranging from -8° (retroversion) to 52° (anteversion) with a typically developing baseline of 12° of anteversion and implemented a Monte Carlo analysis for variations in lower limb muscle forces. While total patellofemoral joint load decreased with increasing femoral anteversion, patellofemoral joint load alignment worsened, and knee abduction/adduction magnitude increased with both positive and negative changes in femoral anteversion (p < 0.001). The rectus femoris muscle was found to greatly influence patellofemoral joint loads across all femoral anteversion alignments (R > 0.8, p < 0.001), and the medial gastrocnemius was found to greatly influence knee abduction/adduction moments for the extreme version cases (R > 0.74, p < 0.001). Along with the vastus lateralis, which decreased with increasing femoral anteversion (R = 0.89, p < 0.001), these muscles are prime candidates for future experimental and clinical efforts to address joint pain in individuals with extreme femoral version. These findings, along with future modeling efforts, could help clinicians better design treatment strategies for knee joint pain in populations with extreme femoral anteversion or retroversion.