William B. Morrison

The Charcot Foot in Diabetes

The diabetic Charcot foot syndrome is a serious and potentially limb-threatening lower-extremity complication of diabetes. First described in 1883, this enigmatic condition continues to challenge even the most experienced practitioners. Now considered an inflammatory syndrome, the diabetic Charcot foot is characterized by varying degrees of bone and joint disorganization secondary to underlying neuropathy, trauma, and perturbations of bone metabolism. An international task force of experts was convened by the American Diabetes Association and the American Podiatric Medical Association in January 2011 to summarize available evidence on the pathophysiology, natural history, presentations, and treatment recommendations for this entity.

Osteochondral Lesions of the Talus: Localization and Morphologic Data from 424 Patients Using a Novel Anatomical Grid Scheme

Background: The primary aim of this study was to evaluate the true incidence of osteochondral lesions on the talar dome by location and by morphologic characteristics on MRI. Because no universally accepted localization system for talar dome osteochondral lesions currently exists, we established a novel, nine-zone anatomical grid system on the talar dome for an accurate depiction of lesion location. Methods: We assigned nine zones to the talar dome articular surface in an equal 3 × 3 grid configuration. Zone 1 was the most anterior and medial, zone 3 was anterior and lateral, zone 7 was most posterior and medial, and zone 9 was the most posterior and lateral. The grid was designed with all nine zones being equal in surface area. Two observers reviewed MRI examinations of 428 ankles in 424 patients (211 males and 213 females; mean age 43 years; age range 6 to 85 years) with reported osteochondral talar lesions. We recorded the frequency of involvement and size of lesion for each zone. Statistical analyses were performed using ANOVA and Scheffe tests. Results: Four hundred and twenty-eight lesions were identified on MRI. The medial talar dome was more frequently involved (n = 269, 62%) than the lateral talar dome (n = 143, 34%). In the AP direction, the mid talar dome (equator) was much more frequently involved (n = 345, 80%) than the anterior (n = 25, 6%) or posterior (n = 58, 14%) thirds of the talar dome. Zone 4 (medial and mid) was most frequently involved (n = 227, 53%), and zone 6 (lateral and mid) was second most frequently involved (n = 110, 26%). Lesions in the medial third of the talar dome were significantly larger in surface area involvement and deeper than those at the lateral talar dome. Conclusions: Our established nine-grid scheme is a useful tool for localizing and characterizing osteochondral talar lesions, which are most frequently located in zone 4 at the medial talar dome, and second most in zone 6 at the lateral talar dome near its equator. Medial talar dome lesions are not only more common but are larger in surface area and in depth than lateral lesions. Posteromedial and anterolateral lesions rarely were found.

Athletic pubalgia and the "sports hernia": MR imaging findings

PURPOSE To retrospectively determine the sensitivity and specificity of magnetic resonance (MR) imaging findings in patients with clinical athletic pubalgia, with either surgical or physical examination findings as the reference standard. MATERIALS AND METHODS Institutional review board approval was granted for this HIPAA-compliant study, and informed consent was waived. MR imaging studies in 141 patients (134 male patients, seven female patients; mean age, 30.1 years; range, 17-71 years) who had been referred to a subspecialist because of groin pain were reviewed for findings including hernia, pubic bone marrow edema, secondary cleft sign, and rectus abdominis and adductor tendon injury. MR imaging findings were compared with surgical findings for 102 patients, physical examination findings for all 141 patients, and MR imaging findings in an asymptomatic control group of 25 men (mean age, 29.8 years; range, 18-39 years). Sensitivity and specificity of MR imaging for rectus abdominis and adductor tendon injury were determined by using a chi(2) analysis, and significance of the findings was analyzed with an unpaired Student t test. Disease patterns seen at MR imaging were compared with those reported in the surgical and sports medicine literature. RESULTS One hundred thirty-eight (98%) of 141 patients had findings at MR imaging that could cause groin pain. Compared with surgery, MR imaging had a sensitivity and specificity, respectively, of 68% and 100% for rectus abdominis tendon injury and 86% and 89% for adductor tendon injury. Injury in each of these structures was significantly more common in the patient group than in the control group (P < .001). Only two patients had hernias at surgery. At MR imaging, injury or disease could be fit into distinct groups, including osteitis pubis, adductor compartment injury, rectus abdominis tendon injury, and injury or disease remote from the pubic symphysis. Patients with injury involving the rectus abdominis insertion were most likely to go on to surgical pelvic floor repair. CONCLUSION MR imaging depicts patterns of findings in patients with athletic pubalgia, including rectus abdominis insertional injury, thigh adductor injury, and articular diseases at the pubic symphysis (osteitis pubis).

Medial patellofemoral ligament injury following acute transient dislocation of the patella: MR findings with surgical correlation in 14 patients.

Purpose The purpose of this study was to determine the accuracy of MRI in determining both the extent and the location of injury to the medial patellofemoral ligament (MPFL). Method MR findings were compared to the surgical results of 14 consecutive patients who experienced transient patellar dislocation. Two musculoskeletal radiologists, blinded to the surgical results, retrospectively reviewed the MR studies, and a consensus reading was obtained. Results Surgery demonstrated complete disruption of the MPFL in 7 of 14 patients (50%), with stretching or partial tearing of the MPFL in the remaining 7 (50%) patients. MRI was 85% sensitive and 70% accurate in detecting MPFL disruption. Vastus medialis obliquus muscle elevation was present in 12 of 14 (85%). Conclusion MRI accurately depicts both the extent and the location of MPFL injury following transient patellar dislocation and can therefore play a significant role in directing surgical management of these patients.

MRI criteria for patella alta and baja

ObjectiveTo determine the range of the patellar tendon length to patellar length ratio on magnetic resonance imaging (MRI) of the knee in order to aid in the establishment of MRI criteria for patella alta and baja.PatientsTwo hundred and forty-five patients ages 6–85 (mean 44) years who went through 262 consecutive 1.5 MRI studies of the knee performed during November 2000 through February 2001 were evaluated, regardless of their clinical symptoms.DesignPatellar length (PL) and patellar tendon length (TL) were measured by a single musculoskeletal radiologist on sagittal images by a line connecting the superior and inferior patellar poles and the shortest length of the inner margin of the tendon respectively. TL/PL ratio was subsequently calculated. The distribution of ratios was evaluated; the extreme 2.5% at each end of the distribution was defined as patella alta and baja.ResultsThe TL/PL ratio ranged between 0.56 and 1.71 (mean 1.05). After plotting the ratios, we noted an asymmetric curve skewed to the left. Based upon calculation of the extreme 2.5% of the ratio at each end of the plot, we determined that the MRI definition of patella alta and baja is a ratio of TL/PL of more than 1.50 and less than 0.74 respectively. We found that females had significantly higher TL/PL ratio than males (1.0878 and 1.0032 respectively). Ratios defined for patella alta and baja were 1.52 and 0.79 respectively in females and 1.32 and 0.74 respectively in males (p<0.0001).ConclusionPatella alta and baja are determined as TL/PL of more than 1.50 and less than 0.74 respectively, somewhat different than traditionally quoted radiographic and previously described MRI criteria.

Musculoskeletal imaging: medicare use, costs, and potential for cost substitution.

PURPOSE The current study explores the substitution of ultrasound (US) for magnetic resonance imaging (MRI) of musculoskeletal (MSK) disorders by describing the recent use and costs of MSK imaging in the Medicare population, projecting these trends from 2006 to 2020, and estimating cost-savings involved in substituting MSK US for MSK MRI, when appropriate. METHODS The study used government-published data sets and de-identified Radiology Information System records exempt from institutional review board approval. From 1 years MSK MRI records (n = 3,621), the proportion of cases in which US could be substituted for MRI was estimated. The use rates for 4 modalities of MSK imaging and average costs were determined from government Medicare data sets from 1996 to 2005. Regression analysis was used to project use rates from 2006 to 2020. The effect on costs of substitution was calculated. RESULTS For the Medicare population, although there has been a moderate overall increase (25.7%) in MSK imaging, MSK MRI has increased 353.5% from 1996 to 2005. Projected MSK imaging costs in 2020 are

Knee Articular Cartilage Damage in Osteoarthritis: Analysis of MR Image Biomarker Reproducibility in ACRIN-PA 4001 Multicenter Trial

3.6 billion, of which

Autogenous osteochondral "plug" transfer for the treatment of focal chondral defects: postoperative MR appearance with clinical correlation.

2.0 billion will be for MRI. A study of 3,621 MSK MRI reports indicates that 45.4% of primary diagnoses and 30.6% of all diagnoses could have been made with MSK US. The substitution of MSK US for MSK MRI, when appropriate, would lead to savings of more than

Prediction of Midfoot Instability in the Subtle Lisfranc Injury: Comparison of Magnetic Resonance Imaging with Intraoperative Findings

6.9 billion in the period from 2006 to 2020. CONCLUSION MRI MSK use has grown substantially from 1996 to 2005. The substitution of MSK US, when appropriate, would lead to large cost-savings for Medicare.

MR Imaging of the Diabetic Foot

PURPOSE To prospectively determine the reproducibility of quantitative magnetic resonance (MR) imaging biomarkers of the morphology and composition (spin lattice relaxation time in rotating frame [T1-ρ], T2) of knee cartilage in a multicenter multivendor trial involving patients with osteoarthritis (OA) and asymptomatic control subjects. MATERIALS AND METHODS This study was HIPAA compliant and approved by the institutional review committees of the participating sites, with written informed consent obtained from all participants. Fifty subjects from five sites who were deemed to have normal knee joints (n = 18), mild OA (n = 16), or moderate OA (n = 16) on the basis of Kellgren-Lawrence scores were enrolled. Each participant underwent four sequential 3-T knee MR imaging examinations with use of the same imager and with 2-63 days (median, 18 days) separating the first and last examinations. Water-excited three-dimensional T1-weighted gradient-echo imaging, T1-ρ imaging, and T2 mapping of cartilage in the axial and coronal planes were performed. Biomarker reproducibility was determined by using intraclass correlation coefficients (ICCs) and root-mean-square coefficients of variation (RMS CVs, expressed as percentages). RESULTS Morphometric biomarkers had high reproducibility, with ICCs of 0.989 or greater and RMS CVs lower than 4%. The largest differences between the healthy subjects and the patients with radiographically detected knee OA were those in T1-ρ values, but precision errors were relatively large. Reproducibility of T1-ρ values was higher in the thicker patellar cartilage (ICC range, 0.86-0.93; RMS CV range, 14%-18%) than in the femorotibial joints (ICC range, 0.20-0.84; RMS CV range, 7%-19%). Good to high reproducibility of T2 was observed, with ICCs ranging from 0.61 to 0.98 and RMS CVs ranging from 4% to 14%. CONCLUSION MR imaging measurements of cartilage morphology, T2, and patellar T1-ρ demonstrated moderate to excellent reproducibility in a clinical trial network.