Do Patients' Perceptions of Leg Length Correlate With Standing 2- and 3-Dimensional Radiographic Imaging?

BACKGROUND: This study compared 2- and 3-dimensional (2D and 3D) radiographic measurements of anatomical and functional leg length and knee coronal and sagittal alignments and correlated these measurements with patients' leg-length perceptions. METHODS: Patients without symptomatic spinal pathology, previous surgery of the spine, and lower extremities (140 lower extremities) were evaluated on EOS images obtained in standing position. Numerous measurements of each limb were compared to the contralateral limb. All 2D/3D measures were evaluated and compared for repeatability and reproducibility. RESULTS: Mean 2D functional and anatomical lengths were 78.7 cm (64.7-88.4, confidence interval [CI] 95%: 77.4-80) and 78.3 cm (64.9-87.9, CI 95%: 77-79.6), respectively. Mean 3D functional and anatomical lengths were 78.9 cm (65.1-88.7, CI 95%: 77.6-80.2) and 78.9 cm (65.6-88.3, CI 95%: 77.8-80.5), respectively (P < .001). Mean 2D and 3D knee varus/valgus angles were -1.9° (-26.4 to 9.1, CI 95%: -3.5 to -0.7) and -0.9° (-19.2 to 11.8, CI 95%: -2.4 to 0.2), respectively (P = .004). Multiple regression analysis found that patients with >10° of flexum/recurvatum were 2.1× more likely to perceive unequal length (P < .1). Patients with irreducible varus/valgus knee deformity were 4× more likely to perceive unequal length (P < .04). CONCLUSION: EOS imaging allows more accurate assessment of anatomical and functional lengths. Patients' perceptions of lower extremity length may correlate more closely with coronal and sagittal alignments of the knee than with femoral or tibial length. This study highlights the importance of physical examination of all the joints and 3D measurements in functional standing position.

Evaluation of the 96/4 PLDLLA polymer resorbable lumbar interbody cage in a long term animal model.

Arthrodesis using interbody cages has demonstrated high fusion rates. However, permanent cages are exposed to stress-shielding, corrosion, and may require explanation when necessary. Polylactic acid (PLA) bioresorbable cages are developed for avoiding these problems, but significant tissue reaction has been reported with 70/30 PLDLLA in some preclinical animal studies. The objective was to evaluate 96/4 PLDLLA cages in a sheep model over 3 years. Sixteen sheeps underwent one level anterior lumbar interbody fusion using 96/4 PLDLLA cages, filled and surrounded with cancellous bone graft from the iliac crest. Six groups of three animals were killed after 3, 6, 9, 12, 24, and 36 months. Harvested lumbar spine had radiographic, MRI, and CT evaluation and histological analysis. Histological results: cage swelling and slight signs of fragmentation associated to fibrocartilaginous tissue apposition at 3 months; bone remodeling around the cage with direct apposition of the mineralization front at 6 months; active cage degradation and complete fusion around the cage at 9 months; cage fragmentation and partial replacement by bone tissue at 12 months; bone bridges in and around the cage at 24 months; full resorption and intervertebral fusion at 36 months. Radiological results: partial arthrodesis at 3 months; definite peripheral arthrodesis at 6 months; similar aspect at 9 months; significant cage resorption at 12 months; definite inner and outer fusion at 24 months; complete cage resorption and calcification at the location of the cage at 36 months confirmed histological observations. Radiographic, CT scan, MRI, and histological data were consistent for showing progressive resorption of 96/4 PLDLLA, interbody fusion, and bone remodeling, with no significant signs of local intolerance reaction. These results are promising and suggest further development of 96/4 PLDLLA cages.

Appraisal of the extent of chronic allograft vasculopathy in animal models: proposition of a standardized micromorphometric method.

Arterial obstruction due to intimal myproliferation is an outcome used for investigating chronic allograft vasculopathy in animal models. Since harvested tissue may be distorted while processing, discrepancy may happen in the measure of the obstruction. We propose a standardized micromorphometric method for calculating the percentage of obstruction with eliminating the variability in the shape of the vessel cross-section. The mathematical adjustment avoids the overestimation of the percentage of obstruction and improves accuracy.