Jeffrey D. Towers

Retrograde Drilling of Osteochondral Lesions of the Medial Talar Dome

Sixteen patients (16 ankles) with symptomatic osteochondral lesions of the medial talar dome were treated arthroscopically with percutaneous retrograde drilling through the sinus tarsi. The surgical technique allows preservation of intact articular cartilage, in contrast to traditional methods. All patients treated with this technique during a 24-month period were included in the study. Patient age ranged from 16 to 44 years (mean, 33 years). Follow-up ranged from 19 to 38 months (mean, 24 months). A staging system based on magnetic resonance imaging examination was used to grade the lesions preoperatively. Outcome was evaluated using the American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale. Preoperative scores ranged from 35 to 75 points, with a mean of 53.9 points. Postoperative American Orthopaedic Foot and Ankle Society scores ranged from 48 to 100 points, with a mean of 82.6 points. Mean improvement was 25 points. There were no surgical complications. Short-term results were comparable to results reported with other available techniques

Familial resemblance of bone mineral density (BMD) and calcaneal ultrasound attenuation : The BMD in Mothers and Daughters Study

The familial resemblance in bone mineral density (BMD) and calcaneal broadband ultrasound attenuation (BUA) was examined in 207 mother‐daughter pairs. Mothers were participants in the Study of Osteoporotic Fractures. Three groups of daughters were recruited based on their maternal history of “fracture,” “low BMD” without fracture (< 0.58 g/cm2, t‐score < −2.5), and “normal BMD” without fracture (> 0.67 g/cm2, t‐score > −1.6). Data on other potentially heritable factors known to influence BMD and BUA were also collected. BMD was measured at the hip, spine, whole body, and calcaneus. Calcaneal BUA was assessed using the Walker‐Sonix UBA 575. Total hip and femoral neck BMD were significantly lower (5.0–8.0%, p < 0.017) among daughters, in particular premenopausal daughters, of mothers with established osteoporosis (“fracture” or “low BMD”) compared with daughters of mothers at lower risk of osteoporosis (“normal BMD”). BUA did not differ across daughter groups. Lifestyle characteristics (dietary calcium, smoking, physical activity) were not highly correlated in mothers and daughters. Height, weight, and body composition were significantly correlated within mother‐daughter pairs and could be a potential mechanism by which BMD is inherited. Among pre‐ and postmenopausal daughters, heritability estimates ranged from 50–63% and 34–48%, respectively. Heritability for calcaneal BUA (53%) was evident among postmenopausal daughters only. In conclusion, familial association in BMD was strongest among premenopausal daughters. Estimates of heritability suggest that maternal BMD and BUA are important independent predictors of BMD and BUA among daughters, reinforcing the importance of prevention and early intervention among women with a positive family history of osteoporosis. (J Bone Miner Res 1999;14: 102–110)

Shoulder magnetic resonance imaging abnormalities, wheelchair propulsion, and gender.

OBJECTIVE To investigate the relationship between pushrim forces and the progression of shoulder injuries in manual wheelchair users. DESIGN Longitudinal case series. SETTING Biomechanics laboratory and magnetic resonance imaging (MRI) facility at a Veterans Health Administration medical center and university hospital, respectively. PARTICIPANTS Fourteen individuals with spinal cord injury (8 men, 6 women) who used manual wheelchairs. INTERVENTION Subjects propelled their own wheelchairs on a dynamometer at 0.9 and 1.8m/s. Bilateral biomechanical data were obtained by using force and moment sensing pushrims at time 1. Bilateral shoulder MR images were also completed on 2 occasions, at time 1 and, approximately 2 years later, at time 2. MAIN OUTCOME MEASURES The peak pushrim forces in a pushrim coordinate system were calculated, weight normalized and averaged over 5 strokes (presented as % body weight). MRI abnormalities were graded by using a summated scale. Differences between scores between times 1 and 2 were calculated. RESULTS Subjects were divided into 2 groups based on change in MRI score. Seven subjects were in the group with worsening scores (MRI+; mean, 8.14 points; range, 5-16), and 7 were in the group with improving or unchanging scores (MRI-; mean, -1.00 point; range, -5 to 1). There was no significant difference between groups with respect to age, body mass index, or years from injury. There were significantly more women in the MRI+ group (6 women, 1 man) than in the MRI- group (7 men) (P=.001). The MRI+ group used significantly greater weight-normalized radial force, or force directed toward the axle at time 1, to propel their wheelchairs at each speed (P<.01): MRI+ at 0.9m/s (mean radial force +/- standard deviation, 5.2%+/-1.0%) and MRI- at 0.9m/s (mean radial force, 3.2%+/-1.7%) (P=.028); and MRI+ at 1.8m/s (mean radial force, 6.6%+/-1.2%) (P=.023) and MRI- at 1.8m/s (mean radial force, 4.1%+/-2.2%). In a separate analysis, women were found to propel with a significantly higher radial force. A logistic regression found a significant relationship between radial force at time 1 and increased risk of progression of MRI findings over time. CONCLUSION Individuals who propel with a greater percentage of force directed toward the axle were at increased risk of progression of MRI findings over time. Most people in this group were women. Clinicians should instruct wheelchair users in effective propulsion techniques and should pay particular attention to women who use wheelchairs. Reducing forces during wheelchair propulsion may minimize the likelihood of developing shoulder injuries.

Normal Appearance and Complications of Double-Bundle and Selective-Bundle Anterior Cruciate Ligament Reconstructions Using Optimal MRI Techniques

OBJECTIVE Double-bundle and selective-bundle anterior cruciate ligament (ACL) reconstructions are increasingly performed to better reproduce the double-bundle anatomy of the native ACL and to improve knee stability and surgical outcomes. This article illustrates how to optimize visualization of the ACL bundle anatomy and the appearances of graft components and postoperative complications. CONCLUSION It is important for the radiologist to be familiar with the appearance of double-bundle and selective-bundle ACL reconstructions and associated complications.

Hamstring Injuries in Professional Football Players: Magnetic Resonance Imaging Correlation With Return to Play

Background: Magnetic resonance imaging (MRI) allows for detailed evaluation of hamstring injuries; however, there is no classification that allows prediction of return to play. Purpose: To correlate time for return to play in professional football players with MRI findings after acute hamstring strains and to create an MRI scoring scale predictive of return to sports. Study Design: Descriptive epidemiologic study. Methods: Thirty-eight professional football players (43 cases) sustained acute hamstring strains with MRI evaluation. Records were retrospectively reviewed, and MRIs were evaluated by 2 musculoskeletal radiologists, graded with a traditional radiologic grade, and scored with a new MRI score. Results were correlated with games missed. Results: Players missed 2.6 ± 3.1 games. Based on MRI, the hamstring injury involved the biceps femoris long head in 34 cases and the proximal and distal hamstrings in 25 and 22 cases, respectively. When < 50% of the muscle was involved, the average number of games missed was 1.8; if > 75%, then 3.2. Ten players had retraction, missing 5.5 games. By MRI, grade I injuries yielded an average of 1.1 missed games; grade II, 1.7; and grade III, 6.4. Players who missed 0 or 1 game had an MRI score of 8.2; 2 or 3 games, 11.1; and 4 or more games, 13.9. Conclusions: Rapid return to play (< 1 week) occurred with isolated long head of biceps femoris injures with < 50% of involvement and minimal perimuscular edema, correlating to grade I radiologic strain (MRI score < 10). Prolonged recovery (missing > 2 or 3 games) occurs with multiple muscle injury, injuries distal to musculotendinous junction, short head of biceps injury, > 75% involvement, retraction, circumferential edema, and grade III radiologic strain (MRI score > 15). Clinical Relevance: MRI grade and this new MRI score are useful in determining severity of injury and games missed—and, ideally, predicting time missed from sports.

FRACTAL ANALYSIS OF TRABECULAR PATTERNS IN PROJECTION RADIOGRAPHS : AN ASSESSMENT

RATIONALE AND OBJECTIVES.Fractal analysis of digitized images has been investigated in recent years as a potential measure of structural bone strength. Several technical issues associated with such measurements are assessed. METHODS.In a series of experiments using a hand phantom, the effects of system noise and modulation transfer function on fractal dimension were explored. The authors evaluated a method for correcting the estimated power spectrum using a step-wedge image exposed and digitized under identical conditions as a reference. RESULTS.System noise and modulation transfer function significantly affect estimated fractal dimension in bony regions computed from conventional radiographs. CONCLUSIONS.Before conventional radiographs are used for fractal analysis in the clinical environment, many of the technical problems associated with this methodology must be addressed.

The pronator quadratus: A distinct forearm space?*

The pronator quadratus sign is associated with fractures of the distal radius and ulna and is believed to be due to accumulation of fluid within the pronator quadratus muscle. This anatomic study based on dye injection and x-ray film examination shows that the pronator quadratus occupies a distinct forearm space without intramuscular communication.

REVISION TOTAL HIP ARTHROPLASTY WITH A RETROPERITONEAL APPROACH TO THE ILIAC VESSELS

Although vascular complications during revision total hip arthroplasty are rare, the results can be devastating. Reports in the literature describe staged operations, with the first procedure being abdominal to remove cement and/or the acetabular component followed by a second joint reconstruction procedure. A protocol was developed that combines a retroperitoneal approach with revision total hip arthroplasty in one operative procedure in patients at risk for vascular injury. The patient first undergoes a retroperitoneal incision and the iliac artery and vein are dissected free of surrounding tissue. A silicone loop is placed around the iliac artery and vein and brought out through the wound. The wound is temporarily closed using staples. Revision total hip arthroplasty then proceeds in the usual fashion. If hemorrhage is encountered, bleeding can be rapidly controlled by tensioning the abdominal vessel loops and opening the incision for exposure to the vessels. No complications have been encountered in 23 patients when using this approach.

Safe zone for anterior cortical perforation of the ulna during tension-band wire fixation: A magnetic resonance imaging analysis

Placing K-wires obliquely through the anterior ulnar cortex is a common modification of traditional olecranon tension-band wiring. Wire tip protrusion, however, risks injury to adjacent neurovascular structures and may impede forearm rotation. This study examines the proximity of neurovascular structures to the anterior proximal ulnar cortex. The anatomy of 47 adult elbows was examined through magnetic resonance imaging. A radiologist measured the spatial relationship of 6 neurovascular structures to a mid-sagittal reference point 1.5 cm distal to the coronoid on the anterior surface of the ulna. Distance and angular measurements were made in the transverse plane of the reference point. Within a reasonable arc of K-wire placement, the ulnar artery and median nerve were at greatest risk yet were still beyond 10 mm from the anterior ulnar cortex. To avoid iatrogenic neurovascular injury during tension-band wiring of the olecranon, protrusion of wire tips beyond the anterior ulnar cortex should be no more than 1 cm at a distance of 1.5 cm distal to the coronoid.

Carpal impaction with the ulnar styloid process : Treatment with partial styloid resection

Carpal impaction with the ulnar styloid process (stylocarpal impaction) occurs less frequently than with the ulnar head (ulnocarpal impaction), and more commonly develops in wrists with negative ulnar variance. Physical examination, radiographic evaluation, and wrist arthroscopy are all helpful in excluding alternative causes of ulnar wrist pain. When an ulnocarpal stress test elicits pain, and radiographs suggest that this is due to carpal impaction with the ulnar styloid, partial resection of the styloid process provides successful treatment, so long as the insertion of the triangular fibrocartilage at the base of the styloid is not disrupted.