Distal Nail Target and Alignment of Distal Tibia Fractures.

OBJECTIVES: To assess the relationship between the distal nail target and postoperative alignment for distal tibia fractures treated with intramedullary nailing. DESIGN: Retrospective cohort study. SETTING: A single level 1 trauma center. PATIENTS/PARTICIPANTS: One hundred thirty distal tibia fractures treated with intramedullary nailing over a 10-year period. MAIN OUTCOME MEASUREMENTS: Malalignment >5 degrees. RESULTS: Thirty-eight cases (29.2%) of malalignment >5 degrees included valgus (19 cases, 14.6%), procurvatum (13 cases, 10.0%), recurvatum (1 case, 0.8%), and combined valgus with procurvatum (5 cases, 3.8%). Medially directed nails demonstrated relative valgus (mean lateral distal tibia angle 86.4 vs. 89.4 degrees, P < 0.01) and more frequent coronal malalignment (24 of 78, 30.8% vs. 0 of 52, 0%, P < 0.01). Anteriorly directed nails demonstrated relative procurvatum (mean anterior distal tibia angle 82.8 vs. 80.9 degrees, P < 0.01) and more frequent sagittal malalignment (15 of 78, 19.2% vs. 3 of 52, 5.8%, P = 0.03). Malalignment was less common for nails targeting the central or slightly posterolateral plafond (0 of 30, 0% vs. 38 of 100, 38%), P < 0.01. Multivariate analysis demonstrated the distal nail target (P = 0.03), fracture within 5 cm of the plafond (P = 0.01), as well as night and weekend surgery (P = 0.03) were all independently associated with malalignment. CONCLUSIONS: Alignment of distal tibia fractures is sensitive to both injury and treatment factors. Nails should be targeted centrally or slightly posterolaterally to minimize malalignment. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Hypovitaminosis D in Orthopaedic Trauma: Which Guidelines Should Be Followed?

OBJECTIVE: To evaluate the risk factors for hypovitaminosis D and to determine the baseline vitamin D supplementation associated with normal vitamin D levels at presentation. DESIGN: Prospective observational study. SETTING: Level I trauma center. PATIENTS: This study included 259 adult patients undergoing operative treatment for orthopaedic trauma (OTA 11-15, 21-23, 31-34, 41-44, 61-62, 70C, 81-82, 87) between January 1, 2014, and December 31, 2014. INTERVENTION: Prospective, observational study. MAIN OUTCOMES: Association of hypovitaminosis D with patient characteristics, injury factors, and vitamin D supplementation. RESULTS: Univariate predictors of hypovitaminosis D included a lack of preinjury supplementation, non-white race, younger age, female sex, non-Medicare insurance, smoking, obesity, Charlson Comorbidity Index <2, and high-energy mechanism. On multivariate analysis, preinjury supplementation was associated with a lower risk (odds ratio: 0.31, 95% confidence interval: 0.15-0.63, P = 0.001) and non-white race was associated with a higher risk (odds ratio: 3.63, 95% confidence interval: 1.58-8.37, P = 0.001) of hypovitaminosis D. Logistic regression analysis found a dose-dependent relationship between vitamin D supplementation and hypovitaminosis D. Each 100-IU increase in vitamin D supplementation was associated with an 8% decrease in the risk of hypovitaminosis D. CONCLUSIONS: A lack of preinjury supplementation and non-white race were independently associated with hypovitaminosis D. Baseline supplementation consistent with Endocrine Society guidelines (2000 IU daily) was more effective than that consistent with Institute of Medicine guidelines (400 IU daily) in maintaining 25-hydroxyvitamin D above 30 ng/mL in this population. LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Long Bone Union Accurately Predicted by Cortical Bridging within 4 Months.

BACKGROUND: Previous retrospective research found that the presence or absence of bridging callus within 4 months postoperatively discriminated accurately between eventual union and nonunion of fractures of the tibial shaft. However, there remains no consensus regarding early prognostication of long bone nonunion. We prospectively assessed the accuracy and reliability of the presence of any bridging callus within 4 months in a cohort that was expanded to include both tibial and femoral shaft fractures. METHODS: We identified 194 consecutive fractures of the shaft of the tibia (OTA/AO type 42-A, B, or C) and femur (OTA/AO type 32-A, B, or C) that were treated with intramedullary nailing. Exclusions for inadequate follow-up (55), extended delay prior to nailing (10), and skeletal immaturity (3) resulted in a study population of 126 fractures (56 tibiae and 70 femora) in 115 patients. Digital radiographs made between 3 and 4 months postoperatively were independently assessed by 3 orthopaedic traumatologists. The accuracy of assessment of the presence of any bridging callus, bicortical bridging, and tricortical bridging to predict union or nonunion was assessed with chi-square analysis and by interobserver reliability (kappa statistic). RESULTS: The nonunion rate was 4% (5 of 126 fractures). The presence of any bridging callus by 4 months accurately predicted union (121 of 122 fractures) and its absence predicted nonunion (4 of 4 fractures). There was 1 incorrect prediction of union for a fracture that failed to unite (p < 0.001). Bicortical or greater bridging predicted union when present (116 of 116 fractures) and nonunion when absent (5 of 10 fractures), incorrectly predicting that 5 healing fractures would go on to nonunion (p < 0.001). Tricortical or greater bridging predicted union when present (103 of 103 fractures) and nonunion when absent (5 of 23 fractures), incorrectly predicting that 18 healing fractures would go on to nonunion (p < 0.001). Interobserver reliability was calculated for any bridging (kappa value, 0.91), bicortical bridging (kappa value, 0.79), tricortical bridging (kappa value, 0.71), and the exact number of cortices bridged (kappa value, 0.67). CONCLUSIONS: The presence of any bridging callus within 4 months accurately predicts the final healing outcome for tibial and femoral shaft fractures treated with intramedullary nailing. This criterion is simple and reliable, and only standard radiographs are needed to make the determination. Basing the prognosis on the bridging of additional cortices risks overestimation of the nonunion rate and is associated with relatively poor reliability.

Functional Impairment of Patients Undergoing Surgical Correction for Charcot Foot Arthropathy.

BACKGROUND: Investigations using the Medical Outcomes Study Short Form 36 Healthy Survey (SF-36) and the American Orthopaedic Foot & Ankle Society Diabetic Foot Questionnaire (AOFAS-DFQ) have demonstrated a poor quality of life in patients with Charcot foot arthropathy. The Short Musculoskeletal Function Assessment (SMFA) questionnaire has been widely used in patients with a broad range of musculoskeletal disorders. METHODS: Twenty-five consecutive patients undergoing operative correction for diabetes-related Charcot foot arthropathy of the midfoot completed the SMFA prior to undergoing surgery. There were 16 males and 9 females. The average body mass index (BMI) was 37.4 (range 25.8-50.2), and the average hemoglobin A1c was 7.5 (range 5.3-10.1) prior to surgery. RESULTS: All 25 patients exhibited significant impairment in all 6 domains of the SMFA ( P < .0001) as compared to the normative data. There was a high correlation between each of the 6 domains of the SMFA, even after correcting for BMI. CONCLUSION: Charcot foot severely impaired the quality of life in patients beyond the impact of morbid obesity. This impairment equally impacted all of the functional and emotional domains measured with the SMFA as compared with population norms. This investigation provides a benchmark for measuring the impact of operative correction of the deformity. In addition, the SMFA appears to be a valid tool for measuring impairment in this complex patient population. LEVEL OF EVIDENCE: Level II, prospective comparative investigation.

Solution Structure of CCL19 and Identification of Overlapping CCR7 and PSGL-1 Binding Sites.

CCL19 and CCL21 are chemokines involved in the trafficking of immune cells, particularly within the lymphatic system, through activation of CCR7. Concurrent expression of PSGL-1 and CCR7 in naive T-cells enhances recruitment of these cells to secondary lymphoid organs by CCL19 and CCL21. Here the solution structure of CCL19 is reported. It contains a canonical chemokine domain. Chemical shift mapping shows the N-termini of PSGL-1 and CCR7 have overlapping binding sites for CCL19 and binding is competitive. Implications for the mechanism of PSGL-1's enhancement of resting T-cell recruitment are discussed.