Humeral version and neck-shaft angle correlated with demographic parameters in a study of 1104 cadaveric humeri.

BACKGROUND: Baseline anatomic data of the humerus are limited by difficulties in quantifying humeral version and the neck-shaft angle (NSA). This study used a 3-dimensional digitizer to quantify normative values for these variables and to identify possible correlations with demographic categories of age, sex, race, and lateralization. METHODS: Measurements from 1104 cadaveric humeri were collected with a MicroScribe G2 digitizer, which produced 3-dimensional positional data of the proximal and distal humeral articular surfaces, as well as the humeral shaft. Version was measured based on the angle between the proximal and distal articular surfaces in the axial plane. The NSA was measured based on the angle between the proximal articular surface and the proximal humeral shaft in the oblique coronal plane. Multiple regression analysis was used to analyze relationships between age, sex, race, and lateralization vs. version and the NSA. RESULTS: The average age was 56.0 ± 10.5 years. Of the specimens, 738 were from white cadavers and 366 were from black cadavers, and 948 were from men and 156 were from women. Average humeral retroversion was 25° ± 7°. White race and left humeri correlated with increased retroversion. The average NSA was 137° ± 6°. White race correlated with an increased NSA. CONCLUSIONS: This study provides measurements of humeral retroversion and the NSA in a large data set, providing key normative values. The data suggest that version and the NSA are independent of age and sex. Significant differences exist for retroversion vs. race and laterality, as well as for the NSA vs. race. These demographic guidelines can guide future research and individualize care for patients.

Acetabular Global Insufficiency in Patients with Down Syndrome and Hip-Related Symptoms: A Matched-Cohort Study.

BACKGROUND: The etiology of hip instability in Down syndrome is not completely understood. We investigated the morphology of the acetabulum and femur in patients with Down syndrome and compared measurements of the hips with those of matched controls. METHODS: Computed tomography (CT) images of the pelvis of 42 patients with Down syndrome and hip symptoms were compared with those of 42 age and sex-matched subjects without Down syndrome or history of hip disease who had undergone CT for abdominal pain. Each of the cohorts had 23 male and 19 female subjects. The mean age (and standard deviation) in each cohort was 11.3 ± 5.3 years. The lateral center-edge angle (LCEA), acetabular inclination angle (IA), acetabular depth-width ratio (ADR), acetabular version, and anterior and posterior acetabular sector angles (AASA and PASA) were compared. The neck-shaft angle and femoral version were measured in the patients with Down syndrome only. The hips of the patients with Down syndrome were further categorized as stable (n = 21) or unstable (n = 63) for secondary analysis. RESULTS: The hips in the Down syndrome group had a smaller LCEA (mean, 10.8° ± 12.6° compared with 25.6° ± 4.6°; p < 0.0001), a larger IA (mean, 17.4° ± 10.3° compared with 10.9° ± 4.8°; p < 0.0001), a lower ADR (mean, 231.9 ± 56.2 compared with 306.8 ± 31.0; p < 0.0001), a more retroverted acetabulum (mean acetabular version as measured at the level of the centers of the femoral heads [AVC], 7.8° ± 5.1° compared with 14.0° ± 4.5°; p < 0.0001), a smaller AASA (mean, 55.0° ± 9.9° compared with 59.7° ± 7.8°; p = 0.005), and a smaller PASA (mean, 67.1° ± 10.4° compared with 85.2° ± 6.8°; p < 0.0001). Within the Down syndrome cohort, the unstable hips showed greater femoral anteversion (mean, 32.7° ± 14.6° compared with 23.6° ± 10.6°; p = 0.002) and worse global acetabular insufficiency compared with the stable hips. No differences between the unstable and stable hips were found with respect to acetabular version (mean AVC, 7.8° ± 5.5° compared with 7.6° ± 3.8°; p = 0.93) and the neck-shaft angle (mean, 133.7° ± 6.7° compared with 133.2° ± 6.4°; p = 0.81). CONCLUSIONS: Patients with Down syndrome and hip-related symptoms had more retroverted and shallower acetabula with globally reduced coverage of the femoral head compared with age and sex-matched subjects. Hip instability among those with Down syndrome was associated with worse global acetabular insufficiency and increased femoral anteversion, but not with more severe acetabular retroversion. No difference in the mean femoral neck-shaft angle was observed between the stable and unstable hips in the Down syndrome cohort. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Joint line changes and outcomes in constrained versus unconstrained total knee arthroplasty for the type II valgus knee.

PURPOSE: The objective of this study was to compare the outcome of constrained and unconstrained primary total knee arthroplasty (TKA) in the management of the valgus deformity. METHODS: This is a retrospective review of patients with type II valgus knee who underwent primary TKA from 1999 to 2011. There were fifty patients in Group 1 who underwent varus-valgus constrained TKA. They were matched with another fifty patients in Group 2 who underwent unconstrained TKA. RESULTS: The mean joint line shift was significantly higher in Group 1 (+8 mm, SD 6 mm) than in Group 2 (+2 mm, SD 3 mm) (p = 0.03). At 2 years, there was no difference in anterior-posterior stability and mediolateral stability according to the Knee Society Score, and patients in Group 2 reported significantly better mean function score of 66.2 (SD 9.3) (mean 48, SD 7.1 in Group 1) (p = 0.002). Two patients (6 %) in Group 1 underwent revision surgery--one for a broken central peg and the other for aseptic loosening. Three patients (2 %) in Group 2 underwent revision surgery--two for global instability and one for poly wear. The estimated survivorship time was 8.3 years for constrained TKA and 12.0 for unconstrained TKA. CONCLUSION: Constrained TKA was associated with more significant joint line changes for the management of valgus arthritic knee, when compared with unconstrained TKA. LEVEL OF EVIDENCE: Retrospective study, Level III.

Coronal alignment is a predictor of the rotational geometry of the distal femur in the osteo-arthritic knee.

PURPOSE: There is a lot of inter-individual variation in the rotational anatomy of the distal femur. This study was set up to define the rotational anatomy of the distal femur in the osteo-arthritic knee and to investigate its relationship with the overall coronal alignment and gender. METHODS: CT-scans of 231 patients with end-stage knee osteo-arthritis prior to TKA surgery were obtained. This represents the biggest series published on rational geometry of the distal femur in literature so far. RESULTS: The posterior condylar line (PCL) was on average 1.6° (SD 1.9) internally rotated relative to the surgical transepicondylar axis (sTEA). The perpendicular to trochlear anteroposterior axis (⊥TRAx) was on average 4.8° (SD 3.3°) externally rotated relative to the sTEA. The relationship between the PCL and the sTEA was statistically different in the different coronal alignment groups (p < 0.001): 1.0° (SD 1.8°) in varus knees, 2.1° (SD 1.8°) in neutral knees and 2.6° (SD 1.8°) in valgus knees. The same was true for the ⊥TRAx in these 3 groups (p < 0.02).There was a clear linear relationship between the overall coronal alignment and the rotational geometry of the distal femur. For every 1° in coronal alignment increment from varus to valgus, there is a 0.1° increment in posterior condylar angle (PCL vs sTEA). CONCLUSION: The PCL was on average 1.6° internally rotated relative to the sTEA in the osteo-arthritic knee. The relationship between the PCL and the sTEA was statistically different in the different coronal alignment groups. LEVEL OF EVIDENCE: III.

The effects of broiler chicken growth rate on valgus, varus, and tibial dyschondroplasia.

An experiment was conducted to test the hypothesis that the growth rate of broilers influences their susceptibilities to bone abnormalities, causing major leg problems. Leg angulations, described in the twisted legs syndrome as valgus and bilateral or unilateral varus, were investigated in 2 subpopulations of mixed-sex Arkansas randombred broilers. Valgus angulation was classified as mild (tibia-metatarsus angle between 10 and 25°), intermediate (25-45°), or severe (> 45°). Body weight was measured at hatch and weekly until 6 wk of age. There were 8 different settings of approximately 450 eggs each. Two subpopulations, slow growing (bottom quarter, n = 581) and fast growing (top quarter, n = 585), were created from a randombred population based on their growth rate from hatch until 6 wk of age. At 6 wk of age, tibial dyschondroplasia incidences were determined by making a longitudinal cut across the right tibia. The tibial dyschondroplasia bone lesion is characterized by an abnormal white, opaque, unmineralized, and unvascularized mass of cartilage occurring in the proximal end of the tibia. It was scored from 1 (mild) to 3 (severe) depending on the cartilage plug abnormality size. Mean lesion scores of left and right valgus and tibial dyschondroplasia (0.40, 0.38, and 0.06) of fast-growing broilers were higher than those (0.26, 0.28, and 0.02) of slow-growing broilers (P = 0.0002, 0.0037, and 0.0269), respectively. Growth rate was negatively associated with the twisted legs syndrome and a bone abnormality (tibial dyschondroplasia) in this randombred population.