Larry B. Dixon

The effects of arthroscopic partial lateral meniscectomy in an otherwise normal knee: a retrospective review of functional, clinical, and radiographic results

A retrospective review of patients who underwent arthroscopic partial lateral meniscectomy for lateral meniscus tears in otherwise normal knees was conducted to review the long-term functional, clinical, and radiographic results. Twenty-six patients (27 knees) were evaluated by questionnaire; 20 patients (21 knees) also underwent physical examination and radiographic analysis. Minimum follow-up was 5 years and mean follow-up was 8 years. Patient data were obtained from detailed questionnaires, knee examinations, and radiographs. Excellent or good results decreased from 92% at the time of maximal improvement to 62% at the most recent follow-up: 85% of patients were initially able to return to their preinjury activity level; however, only 48% were able to maintain this level of activity at the most recent follow-up. Seventy-two percent of patients had either one or no Fairbank changes and there was no statistical difference when comparing radiographic criteria in the operated and nonoperated knee. Early results for partial lateral meniscectomy can be quite good; however, significant deterioration of functional results and decreased activity level can occur. Radiographic changes did not correlate with subjective symptoms and functional outcome in our patient population. Our findings suggest that the functional outcome for patients undergoing partial lateral meniscectomy may deteriorate with time and it may be helpful to counsel patients concerning long-term expectations.

Radiographic texture analysis of densitometer-generated calcaneus images differentiates postmenopausal women with and without fractures

IntroductionBone fragility is determined by bone mass, measured as bone mineral density (BMD), and by trabecular structure, which cannot be easily measured using currently available noninvasive methods. In previous studies, radiographic texture analysis (RTA) performed on the radiographic images of the spine, proximal femur, and os calcis differentiated subjects with and without osteoporotic fractures. The present cross-sectional study was undertaken to determine whether such differentiation could also be made using high-resolution os calcis images obtained on a peripheral densitometer.MethodsIn 170 postmenopausal women (42 with and 128 without prevalent vertebral fractures) who had no secondary causes of osteoporosis and were not receiving treatment for osteoporosis, BMD of the lumbar spine, proximal femur, and os calcis was measured using dual energy x-ray absorptiometry. Vertebral fractures were diagnosed on densitometric spine images. RTA, including Fourier-based and fractal analyses, was performed on densitometric images of os calcis.ResultsBMD at all three sites and all texture features was significantly different in subjects with and without fractures, with the most significant differences observed for the femoral neck and total hip measurements and for the RTA feature Minkowski fractal (p<0.001). In univariate logistic regression analysis, Minkowski fractal predicted the presence of vertebral fractures as well as femoral neck BMD (p<0.001). In multivariate logistic regression analysis, both femoral neck BMD and Minkowski fractal yielded significant predictive effects (p=0.001), and when age was added to the model, the effect of RTA remained significant (p=0.002), suggesting that RTA reflects an aspect of bone fragility that is not captured by age or BMD. Finally, when RTA was compared in 42 fracture patients and 42 nonfracture patients matched for age and BMD, the RTA features were significantly different between the groups (p=0.003 to p=0.04), although BMD and age were not.ConclusionThis study suggests that RTA of densitometer-generated calcaneus images provides an estimate of bone fragility independent of and complementary to BMD measurement and age.

Radiofrequency ablation of solitary eosinophilic granuloma of bone

OBJECTIVE This article about our initial clinical experience describes the novel application of radiofrequency ablation for the treatment of two cases of solitary eosinophilic granuloma of the bone. CONCLUSION Technical success was achieved in both cases with a prompt clinical response and no treatment-related complications. To our knowledge, this is the first description of the application of radiofrequency ablation for the treatment of solitary eosinophilic granuloma of the bone.

Comparison of radiographic texture analysis from computed radiography and bone densitometry systems.

Osteoporosis is a disease that results in an increased risk of bone fracture due to a loss of bone mass and deterioration of bone structure. Bone mineral density (BMD) provides a measure of bone mass and is frequently measured by bone densitometry systems to diagnose osteoporosis. In addition, computerized radiographic texture analysis (RTA) is currently being investigated as a measure of bone structure and as an additional diagnostic predictor of osteoporosis. In this study, we assessed the ability of a peripheral bone densitometry (PD) system to yield images useful for RTA. The benefit of such a system is that it measures BMD by dual-energy x-ray absorptiometry and therefore provides high- and low-energy digital radiographic images. The bone densitometry system investigated was the GE/Lunar PIXI, which provides 512 x 512 digital images of the heel or forearm (0.2 mm pixels). We compared texture features of heel images obtained with this PD system to those obtained on a Fuji computed radiography (CR) system (0.1 mm pixels). Fourier and fractal-based texture features of images from 24 subjects who had both CR and BMD exams were calculated, and correlation between the two systems was analyzed. Fourier-based texture features characterize the magnitude, frequency content, and orientation of the trabecular bone pattern. Good correlation was found between the two modalities for the first moment (FMP) with r=0.71 (p value<0.0001) and for minimum FMP with r=0.52 (p value=0.008). Root-mean-square (RMS) did not correlate with r=0.31 (p value>0.05), while the standard deviation of the RMS did correlate with r=0.79 (p value<0.0001). Good correlation was also found between the two modalities for the fractal-based texture features with r=0.79 (p value<0.0001) for the global Minkowski dimension and r=0.63 (p value=0.0007) for the fractal dimension from a box counting method. The PD system therefore may have the potential for yielding heel images suitable for RTA.

Radiographic analysis of solitary bone lesions.

Solitary bone lesions are common diagnostic dilemmas. Conventional radiography is frequently the initial imaging study for evaluation. This article provides an organized approach to analyzing and categorizing these lesions based on radiographs, emphasizes the development of a reasonable and accurate differential diagnosis, and guides the referring physician if further imaging evaluation is warranted. Use of clinical information and analysis of specific radiographic features, including lesion location, rate of growth, the presence and character of periosteal reaction, tumor matrix, and the presence of an associated soft tissue mass is reviewed. Radiographic evaluation of soft tissue masses is briefly discussed.