Traumatic Hip Dislocation: Pediatric and Adult Evaluation and Management.

Traumatic hip dislocation of a native hip joint represents an orthopaedic emergency that should be treated promptly. Dislocations can be classified based on the associated injuries and the direction of dislocation. Expeditious evaluation, reduction, and management of associated injuries are required to optimize short and long-term function of the hip. There are several important differences between the blood supply and ossification of the pediatric hip that necessitate different strategies for the evaluation and management of traumatic hip dislocations in pediatric patients. Appropriate treatment is dictated by the direction and type of dislocation as well as associated injuries. In addition to closed reduction, arthroscopy, open reduction (potentially with fracture fixation and/or soft-tissue repair), osteotomy, and total hip arthroplasty all have roles in treatment. Consensus on optimal postreduction activity protocols after simple hip dislocation remain unestablished. Short and long-term outcomes are largely driven by the amount of time from injury to reduction and associated injuries.

Optimizing calibration of modern skeletal maturity systems.

Purpose: Greulich and Pyle is the most used system to estimate skeletal maturity but has significant drawbacks, prompting the development of newer skeletal maturity systems, such as the modified Fels skeletal maturity systems based on knee radiographs. To create a new skeletal maturity system, an outcome variable, termed a "skeletal maturity standard," must be selected for calibration of the system. Peak height velocity and 90% of final height are both considered reasonable skeletal maturity standards for skeletal maturity system development. We sought to answer two questions: (1) Does a skeletal maturity system developed using 90% of final height estimate skeletal age as well as it would if it was instead developed using peak height velocity? (2) Does a skeletal maturity system developed using 90% of final height perform as well in lower extremity length prediction as it would if it was instead developed using peak height velocity? Methods: The modified Fels knee skeletal maturity system was recalibrated based on 90% of final height and peak height velocity skeletal maturity standards. These models were applied to 133 serially obtained, peripubertal antero-posterior knee radiographs collected from 38 subjects. Each model was used to estimate the skeletal age of each radiograph. Skeletal age estimates were also used to predict each patient's ultimate femoral and tibial length using the White-Menelaus method. Results: The skeletal maturity system calibrated with 90% of final height produced more accurate skeletal age estimates than the same skeletal maturity system calibrated with peak height velocity (p < 0.05). The 90% of final height and peak height velocity models made similar femoral and tibial length predictions (p > 0.05). Conclusion: Using the 90% of final height skeletal maturity standard allows for simpler skeletal maturity system development than peak height velocity with potentially more accuracy.

Perioperative allogenic blood transfusions are associated with increased fracture related infection rates, but not nonunion in operatively treated distal femur fractures.

INTRODUCTION: Distal femur fractures are common injuries that remain difficult for orthopedic surgeons to treat. High complication rates, including nonunion rates as high as 24% and infection rates of 8%, can lead to increased morbidity for these patients. Allogenic blood transfusions have previously been identified as risk factors for infection in total joint arthroplasty and spinal fusion surgeries. No studies have explored the relationship between blood transfusions and fracture related infection (FRI) or nonunion in distal femur fractures. METHODS: 418 patients with operatively treated distal femur fractures at two level I trauma centers were retrospectively reviewed. Patient demographics were collected including age, gender, BMI, medical comorbidities, and smoking. Injury and treatment information was also collected including open fracture, polytrauma status, implant, perioperative transfusions, FRI, and nonunion. Patients with less than three months of follow up were excluded. RESULTS: 366 patients were included in final analysis. One hundred thirty-nine (38%) patients received a perioperative blood transfusion. Forty-seven (13%) nonunions and 30 (8%) FRI were identified. Allogenic blood transfusion was not associated with nonunion (13% vs 12%, P = 0.87), but was associated with FRI (15% vs 4%, P<0.001). Binary logistic regression analysis identified a dose dependent relationship between number of perioperative blood transfusions and FRI: total transfusion ≥2 U PRBC RR= 3.47(1.29, 8.10, P = 0.02), ≥3 RR= 6.99 (3.01, 12.40, P<0.001), and ≥4 RR= 8.94 (4.03, 14.42, P<0.001). DISCUSSION: In patients undergoing operative treatment of distal femur fractures, perioperative blood transfusions are associated with increased risk of fracture related infection, but not the development of a nonunion. This risk association increases in a dose-dependent relationship with increasing total blood transfusions received.

Applicability of the Modified Fels and Optimized Oxford Skeletal Maturity Estimation Systems to the Modern Pediatric Population.

BACKGROUND: The recently developed modified Fels knee and optimized Oxford hip skeletal maturity systems (SMS) have demonstrated impressive performance compared with the Greulich and Pyle skeletal age atlas when applied to the same historical, mostly white, pediatric population. We sought to determine whether these 2 systems require modification before being used in modern children. METHODS: We collected knee and hip radiographs between January 2015 and September 2020 from our electronic medical record from 4 groups of children: (1) white males, (2) black males, (3) white females, and (4) black females. Males between 9 and 17 years and females between 7 and 15 years were included. After reliability analyses, 5 nonpathologic radiographs for each age and joint were randomly selected from each group and evaluated with the appropriate SMS. The mean discrepancy between each group's chronological age at the time of radiograph and estimated skeletal age was compared between our modern cohort and the historical Bolton-Brush children. After normality testing, paired t tests or Wilcoxon signed-rank tests were performed, as appropriate. A Bonferroni correction was applied to address multiple testing. RESULTS: Three hundred sixty modern radiographs were evaluated (180 knees and 180 hips). All 7 modified Fels knee parameters and all 5 optimized Oxford hip parameters had inter and intrarater reliability coefficients ≥0.7, indicating good to very good reliability. For the modified Fels knee SMS, white males (Δ0.74 y, P <0.001), black males (Δ0.69 y, P <0.001), and black females (Δ0.4 y, P =0.04) had advanced skeletal age compared with their historical counterparts of the same sex. No differences were found between historical and modern patients for the optimized Oxford hip SMS. No differences were found for either SMS comparing modern patients along racial lines ( P >0.05 for all). CONCLUSIONS: Discrepancies in skeletal age estimates made by the modified Fels knee SMS exist between modern pediatric white males, black males, and black females and their historic counterparts. No differences were found when using optimized Oxford hip SMS. Future studies should evaluate how these translate to clinical decision-making. LEVEL OF EVIDENCE: Level III; retrospective chart review.

The Utility of the Modified Fels Knee Skeletal Maturity System in Limb Length Prediction.

BACKGROUND: Predicting ultimate lower extremity length is important in the treatment of lower limb length discrepancy (LLD), congenital limb deficiency, and other etiologies. Utilizing skeletal age over chronological age improves the prediction of ultimate lower extremity length. The recently described modified Fels knee skeletal maturity system allows for skeletal age estimation via imaging always available in LLD patients. We sought to compare the accuracy of the modified Fels knee skeletal maturity system versus chronological age in ultimate limb length prediction of a modern adolescent clinical population. METHODS: The medical records of all patients treated at our institution over a 20-year period with unilateral lower extremity pathology and available lower extremity imaging before and after reaching skeletal maturity were reviewed. Skeletal maturity was defined radiographically by closed distal femoral, proximal tibial, and proximal fibular physes. The femoral, tibial, and lower extremity length was measured in all radiographs. The modified Fels knee skeletal maturity system was applied to all radiographs obtained before maturity to estimate skeletal age. The accuracy of 3 widely utilized lower extremity length prediction systems was compared when utilizing estimated Fels skeletal age versus chronological age inputs. RESULTS: A total of 245 radiographs (109 before maturity) from 43 patients were eligible for inclusion. On cross-sectional analysis, linear modeling using Fels skeletal ages was uniformly associated with higher (improved) R2 values than chronological age-based models. On longitudinal analysis, skeletal age mixed-effects models had significantly lower (improved) Akaike information criterion and Bayesian information criterion values than chronological age models in all cases. Cohen d values were also significantly different (P<0.05) for the skeletal age models compared with chronological age models in all cases. CONCLUSIONS: In the treatment of LLD, the modified Fels knee skeletal maturity system can be readily applied to available imaging to improve the prediction of ultimate femoral, tibial, and lower extremity length. This skeletal maturity system may have significant utility in the estimation of ultimate LLD and determination of appropriate timing of epiphysiodesis. LEVEL OF EVIDENCE: Level III.

Systematic Isolation of Key Parameters for Estimating Skeletal Maturity on AP Hip Radiographs.

BACKGROUND: The ability to estimate skeletal maturity using a hip radiograph does not yet exist, but may have utility in the treatment of scoliosis, slipped capital femoral epiphysis, and lower limb deformity. We sought to develop a fast, accurate, and reproducible method. METHODS: Fourteen hip radiologic parameters were evaluated on serial anteroposterior hip radiographs from 3 years before to 2 years after the skeletal age associated with 90% of final height, a validated skeletal maturity definition which correlates with the timing of peak height velocity. The Greulich and Pyle (GP) left hand bone age was obtained for comparison. Stepwise linear regression and generalized estimating equation analyses were used to isolate key hip and demographic parameters, creating the "optimized Oxford" skeletal maturity system. The accuracy of the optimized Oxford system in predicting years from 90% of final height was evaluated and compared with systems of demographics only, the modified Oxford, demographics+modified Oxford, and demographics+GP. RESULTS: A total of 284 hip radiographs from 41 girls (range: 7 to 15 y) and 38 boys (range: 9 to 17 y) were included. Following multivariate analyses, 5 of the original 14 hip radiographic parameters remained significant. The predictions made by the optimized Oxford model had greater accuracy and fewer outlier predictions (predictions >1 y off from actual years from 90% of final height) than the demographics only and modified Oxford only models (P<0.05 for all). The optimized Oxford model had greater prediction accuracy than the demographics+modified Oxford model, but similar rates of outlier predictions (P=0.903). No differences in mean prediction accuracy or rate of outlier predictions were observed between the optimized Oxford and the demographics+GP model (P>0.05). CONCLUSION: High precision in skeletal maturity estimation can be achieved by using chronological age, sex, and 5 hip radiographic parameters. CLINICAL RELEVANCE: We have developed a skeletal maturity system that utilizes anteroposterior hip radiographs and performs as accurately as GP.

Estimating Skeletal Maturity Using Knee Radiographs During Preadolescence: The Epiphyseal:Metaphyseal Ratio.

BACKGROUND: Though skeletal maturity is most relevant during adolescence, it has utility in treatment of younger patients in some circumstances. Accurate estimation of skeletal maturity using knee radiographs would be useful when treating limb length discrepancy and other general medical conditions in preadolescent patients. Currently, a quick, accurate, and reproducible method of estimating skeletal maturity in preadolescents is lacking. METHODS: Serial anteroposterior knee radiographs taken at historical growth study visits leading up to the chronological age associated with 90% of final height (an enhanced skeletal maturity standard as compared with peak height velocity) were analyzed in 75 children. Epiphyseal and metaphyseal widths of the distal femur, proximal tibia, and proximal fibula were measured and the epiphyseal:metaphyseal ratio was calculated. Greulich and Pyle (GP) bone ages were also assigned by an experienced pediatric endocrinologist using left hand radiographs. Stepwise linear regression and generalized estimating equation analyses were used to make a skeletal maturity model incorporating demographics (age+sex) and knee epiphyseal:metaphyseal ratios. RESULTS: A total of 258 left knee radiographs from 39 girls (mean age 8.6 y, range: 2.9 to 13 y) and 36 boys (mean age 10.6 y, range: 3.8 to 15 y) were included. The demographics+ratios model had similar prediction accuracy (0.49 vs. 0.48 y, P=0.84) and rate of outliers (11% vs. 9%, P=0.11) as the demographics+GP model. The demographics+ratios model outperformed all other models evaluated, including a demographics-only model (P<0.001 for all). CONCLUSIONS: When combined with chronological age and sex, epiphyseal:metaphyseal ratio measurement in the knee allows for skeletal maturity estimation comparable to using the GP technique. CLINICAL RELEVANCE: We have defined a knee skeletal maturity system that could be applied in treatment of orthopaedic conditions in preadolescents where a knee radiograph is already obtained, avoiding the need for an additional hand radiograph.

Skeletal Maturity Using Knee X-rays: Understanding the Resilience of 7 Radiographic Parameters to Rotational Position.

BACKGROUND: Recently, a skeletal maturity system using knee radiographs, named the modified Roche-Wainer-Thissen (RWT) system, has been developed using 7 discrete radiographic parameters. While the system has been shown to significantly outperform the Greulich and Pyle atlas, the effect of rotational variation of the knee radiograph on skeletal maturity determinations has not been studied. METHODS: Normal knee computed tomography scans of 12 male children ages 10 to 16 years and 8 female children ages 8 to 14 years were obtained retrospectively, converted into 3-dimensional reconstructions, and then used to simulate knee radiographs in 5 different rotational positions. Images were graded using the modified RWT system, and 1-way repeated measures analysis of variance was used to compare skeletal age in the patella centered view versus the other positions. We next retrospectively found 85 pediatric patients with both bilateral standing anteroposterior hip to ankles and separate knee radiograph within 6 months of each other. The skeletal maturity values from the 2 different radiographs were compared in 39 males between the ages of 10 and 16 years and 46 females between 8 and 14 years of age using paired t test and Wilcoxon-signed rank test. RESULTS: On the computed tomography scan-based images, there was no statistically significant effect of rotational position on the modified RWT score using repeat measures analysis of variance (P=0.210). Only the width ratio of the tibial epiphysis and metaphysis and the width ratio of the fibular epiphysis and metaphysis were statistically different between rotational positions (P<0.05). Comparing clinical full length versus knee radiographs, we found a small difference of 0.069 years which trended towards a statistically significant difference (P=0.009). CONCLUSIONS: This retrospective study supports the resilience of the RWT model to rotational variation, reassuring clinicians that bone age estimation can be performed in a slightly rotated knee x-ray within a reasonable margin of error. These results can minimize the number of radiographs needed to assess skeletal maturity limiting radiation exposure and expedite clinical flow. LEVEL OF EVIDENCE: Level-III-diagnostic study.

Acetabular Fracture Around a Birmingham Hip Resurfacing Prosthesis: A Case Report.

CASE: A traumatic displaced transverse periprosthetic acetabular fracture around a well-functioning Birmingham hip resurfacing prosthesis was treated with open reduction and internal fixation. The acetabular component was found to be well-fixed intraoperatively and did not require revision. The patient recovered with excellent clinical and radiographic results at the 1-year follow-up with a Harris Hip Score of 94. CONCLUSIONS: Internal fixation, rather than revision arthroplasty, offers acceptable outcomes in patients with periprosthetic acetabular fractures about well-fixed hip resurfacing prostheses. Radiographic and intraoperative assessment of stability is critical in guiding treatment.