Juerg Hodler

Magnetic resonance classification of lumbar intervertebral disc degeneration.

Study Design. A reliability study was conducted. Objectives. To develop a classification system for lumbar disc degeneration based on routine magnetic resonance imaging, to investigate the applicability of a simple algorithm, and to assess the reliability of this classification system. Summary of Background Data. A standardized nomenclature in the assessment of disc abnormalities is a prerequisite for a comparison of data from different investigations. The reliability of the assessment has a crucial influence on the validity of the data. Grading systems of disc degeneration based on state of the art magnetic resonance imaging and corresponding reproducibility studies currently are sparse. Methods. A grading system for lumbar disc degeneration was developed on the basis of the literature. An algorithm to assess the grading was developed and optimized by reviewing lumbar magnetic resonance examinations. The reliability of the algorithm in depicting intervertebral disc alterations was tested on the magnetic resonance images of 300 lumbar intervertebral discs in 60 patients (33 men and 27 women) with a mean age of 40 years (range, 10–83 years). All scans were analyzed independently by three observers. Intra- and interobserver reliabilities were assessed by calculating kappa statistics. Results. There were 14 Grade I, 82 Grade II, 72 Grade III, 68 Grade IV, and 64 Grade V discs. The kappa coefficients for intra- and interobserver agreement were substantial to excellent: intraobserver (kappa range, 0.84–0.90) and interobserver (kappa range, 0.69–0.81). Complete agreement was obtained, on the average, in 83.8% of all the discs. A difference of one grade occurred in 15.9% and a difference of two or more grades in 1.3% of all the cases. Conclusion. Disc degeneration can be graded reliably on routine T2-weighted magnetic resonance images using the grading system and algorithm presented in this investigation.

The contour of the femoral head-neck junction as a predictor for the risk of anterior impingement

Impingement by prominence at the femoral head-neck junction on the anterior acetabular rim may cause early osteoarthritis. Our aim was to develop a simple method to describe concavity at this junction, and then to test it by its ability to distinguish quantitatively a group of patients with clinical evidence of impingement from asymptomatic individuals who had normal hips on examination. MR scans of 39 patients with groin pain, decreased internal rotation and a positive impingement test were compared with those of 35 asymptomatic control subjects. The waist of the femoral head-neck junction was identified on tilted axial MR scans passing through the centre of the head. The anterior margin of the waist of the femoral neck was defined and measured by an angle (alpha). In addition, the width of the femoral head-neck junction was measured at two sites. Repeated measurements showed good reproducibility among four observers. The angle alpha averaged 74.0 degrees for the patients and 42.0 degrees for the control group (p < 0.001). Significant differences were also found between the patient and control groups for the scaled width of the femoral neck at both sites. Using standardised MRI, the symptomatic hips of patients who have impingement have significantly less concavity at the femoral head-neck junction than do normal hips. This test may be of value in patients with loss of internal rotation for which a cause is not found.

The Results of Repair of Massive Tears of the Rotator Cuff

Background: Massive tears of the tendons of the rotator cuff cause atrophy and fatty degeneration of the rotator cuff muscles and painful loss of function of the shoulder. Repair of massive rotator cuff tears is often followed by retears of the tendons, additional muscular degeneration, and a poor clinical outcome. The purposes of this study were to determine whether a new method of repair of rotator cuff tendons can yield a lower retear rate and a better clinical outcome than previously reported methods, to assess the muscular changes following repair of massive tears of the musculotendinous units, and to correlate findings on magnetic resonance imaging with the clinical results. Methods: Twenty-nine massive rotator cuff tears involving complete detachment of at least two tendons were repaired operatively with use of a new laboratory-tested technique in a prospective study. At least two years (average, thirty-seven months; range, twenty-four to sixty-one months) postoperatively, twenty-seven patients were evaluated clinically and with magnetic resonance imaging to determine the clinical outcome, the integrity of the repair, and the condition of the rotator cuff muscles. Results: The age and gender-adjusted Constant score improved from an average of 49 percent preoperatively to an average of 85 percent postoperatively, corresponding to a subjective shoulder value of 78 percent of that of a normal shoulder. Pain-free flexion improved from an average of 92 degrees to an average of 142 degrees, and abduction improved from an average of 82 degrees to an average of 137 degrees. Pain decreased and performance of activities of daily living improved significantly (p < 0.05). The seventeen patients who had a structurally successful repair all had an excellent clinical outcome. Muscle atrophy could not be reversed except in successfully repaired supraspinatus musculotendinous units. Fatty degeneration increased in all muscles. Conclusions: The method of repair of massive rotator cuff tears that was used in this study yielded a comparatively low retear rate and good-to-excellent clinical results; however, the repair did not result in substantial reversal of muscular atrophy and fatty degeneration. Retears occurred more often in patients who had had a shorter interval between the onset of the symptoms and the operation (p < 0.05). Patients who had a retear had improvement of the shoulder compared with the preoperative state, but they had less improvement than did those who had a successful repair.

Fatty degeneration of the muscles of the rotator cuff: assessment by computed tomography versus magnetic resonance imaging.

Forty-one patients scheduled for shoulder surgery underwent computed tomography (CT) and magnetic resonance imaging (MRI) examination of their affected shoulder to verify whether fatty degeneration of the rotator cuff muscles could reproducibly be assessed by CT or by MRI and whether the grading with the 2 methods was comparable. In addition, rotator cuff muscle cross-sectional areas were measured on parasagittal MRI scans to establish a possible correlation between rotator cuff muscle atrophy and fatty degeneration. Interobserver reproducibility for grading fatty degeneration was good to excellent for CT and for MRI. The correlation between MRI and CT was fair to moderate and remained unsatisfactory, even if the classification system was simplified with only a 3- rather than a 5-grade scale as originally proposed. The degree of fatty degeneration was significantly related to the amount of atrophy of the respective muscles.

Quantitative assessment of the muscles of the rotator cuff with magnetic resonance imaging.

RATIONALE AND OBJECTIVES The purpose of this study was to establish a magnetic resonance (MR) imaging standard for quantification of the muscles of the rotator cuff. METHODS Parasagittal T1-weighted turbo spin-echo images of the shoulder were obtained in 70 asymptomatic subjects (35 women, 35 men; age range: 21-70 years, mean: 45 years). Standardized cross-sectional areas (rotator cuff muscle areas divided by the area of the supraspinatus fossa) and standardized signal intensities (related to signal intensities of the teres major muscle) were measured and compared with 30 patients with different stages of rotator cuff tears and 10 patients with glenohumeral instability. In addition, a so-called tangent sign was evaluated with the hypothesis that a healthy supraspinatus muscle crosses a line (tangent) drawn through the superior borders of the scapular spine and the superior margin of the coracoid. RESULTS Cross-sectional areas of the muscles of the rotator cuff were variable in asymptomatic subjects. Cross-sectional areas (but not signal intensities) did discriminate patients with different stages of rotator cuff tears from asymptomatic subjects. The tangent sign was negative in all asymptomatic subjects but positive in four and nine of 10 patients with medium and large rotator cuff tears, respectively. CONCLUSIONS A method for quantification of the muscles of the rotator cuff using MR imaging is presented. Cross-sectional areas can be used for quantification of the muscles of the rotator cuff. The tangent sign is a useful MR sign for atrophy of the supraspinatus muscle.

The clinical and structural long-term results of open repair of massive tears of the rotator cuff

BACKGROUND At a mean follow-up of 3.1 years, twenty-seven consecutive repairs of massive rotator cuff tears yielded good and excellent clinical results despite a retear rate of 37%. Patients with a retear had improvement over the preoperative state, but those with a structurally intact repair had a substantially better result. The purpose of this study was to reassess the same patients to determine the long-term functional and structural results. METHODS At a mean follow-up interval of 9.9 years, twenty-three of the twenty-seven patients returned for a review and were examined clinically, radiographically, and with magnetic resonance imaging with use of a methodology identical to that used at 3.1 years. RESULTS Twenty-two of the twenty-three patients remained very satisfied or satisfied with the result. The mean subjective shoulder value was 82% (compared with 80% at 3.1 years). The mean relative Constant score was 85% (compared with 83% at 3.1 years). The retear rate was 57% at 9.9 years (compared with 37% at 3.1 years; p = 0.168). Patients with an intact repair had a better result than those with a failed reconstruction with respect to the mean absolute Constant score (81 compared with 64 points, respectively; p = 0.015), mean relative Constant score (95% and 77%; p = 0.002), and mean strength of abduction (5.5 and 2.6 kg; p = 0.007). The mean retear size had increased from 882 to 1164 mm(2) (p = 0.016). Supraspinatus and infraspinatus muscle fatty infiltration had increased (p = 0.004 and 0.008, respectively). Muscles with torn tendons preoperatively showed more fatty infiltration than muscles with intact tendons preoperatively, regardless of repair integrity. Shoulders with a retear had a significantly higher mean acromion index than those without retear (0.75 and 0.65, respectively; p = 0.004). CONCLUSIONS Open repair of massive rotator cuff tears yielded clinically durable, excellent results with high patient satisfaction at a mean of almost ten years postoperatively. Conversely, fatty muscle infiltration of the supraspinatus and infraspinatus progressed, and the retear size increased over time. The preoperative integrity of the tendon appeared to be protective against muscle deterioration. A wide lateral extension of the acromion was identified as a previously unknown risk factor for retearing.

MR imaging and CT in osteoarthritis of the lumbar facet joints

Abstract Objective. To test the agreement between MR imaging and CT in the assessment of osteoarthritis of the lumbar facet joints, and thus to provide data about the need for an additional CT scan in the presence of an MR examination. Design and patients. Using a four-point scale, two musculoskeletal radiologists independently graded the severity of osteoarthritis of 308 lumbar facet joints on axial T2-weighted and on sagittal T1- and T2-weighted turbo-spin-echo images and separately on the corresponding axial CT scans. Kappa statistics and percentage agreement were calculated. Results. The weighted kappa coefficients for MR imaging versus CT were 0.61 and 0.49 for readers 1 and 2, respectively. The weighted kappa coefficients for interobserver agreement were 0.41 for MR imaging and 0.60 for CT, respectively. There was agreement within one grade between MR and CT images in 95% of cases for reader 1, and in 97% of cases for reader 2. Conclusion. With regard to osteoarthritis of the lumbar facet joints there is moderate to good agreement between MR imaging and CT. When differences of one grade are disregarded agreement is even excellent. Therefore, in the presence of an MR examination CT is not required for the assessment of facet joint degeneration.

Clinical and Structural Results of Open Repair of an Isolated One-Tendon Tear of the Rotator Cuff

BACKGROUND The clinical outcomes of open rotator cuff repair are well established, but the structural results and their effect on clinical outcome are poorly known. We assessed the structural changes in the musculotendinous units after open rotator cuff repair and correlated these findings with the clinical outcome to establish a benchmark for future series. METHODS Thirty-two consecutive standardized open repairs of a single tendon tear of the rotator cuff were analyzed in twenty-one men and eleven women with an average age of 59.0 years. The supraspinatus tendon was involved in twenty-two patients and the subscapularis tendon, in ten. The clinical outcome, including the Constant score, was assessed prospectively for all patients at an average of thirty-eight months postoperatively. The structural outcome was assessed on standardized magnetic resonance imaging scans. RESULTS The mean overall subjective shoulder value was 82.8% of the value for a normal shoulder. On the average, the age and gender-adjusted Constant score increased from 63.9% preoperatively to 94.5% postoperatively (p < 0.0001); the score for pain, from 6.8 points to 13.2 points (p < 0.0001); and the score for activities of daily living, from 11.2 points to 17.9 points (p < 0.0001). The overall rerupture rate was 13% (four of the thirty-two shoulders). All reruptures were distinctly smaller than the original tear. Muscular atrophy or fatty infiltration did not significantly decrease after the tendon repair. In fact, fatty infiltration in the supraspinatus (p < 0.0053) and infraspinatus (p < 0.003) muscles increased significantly. CONCLUSIONS Direct open repair of a complete, isolated tear of one tendon of the rotator cuff resulted in significant subjective and objective improvement and very high patient satisfaction. Successful direct repair was not associated with a decrease in preoperative muscular atrophy and was associated with increased fatty infiltration of the muscle.

Young Investigator Award 2001 Winner : Risk Factors for Lumbar Disc Degeneration : A 5-Year Prospective MRI Study in Asymptomatic Individuals

Study Design. A longitudinal magnetic resonance imaging investigation of lumbar disc degeneration in asymptomatic individuals was conducted. Objective. To investigate risk factors for the development or deterioration of lumbar disc degeneration. Summary of Background Data. Numerous studies have explored the significance of certain risk factors for the development or progression of disc degeneration, but no comprehensive longitudinal magnetic resonance imaging–based study has been reported that simultaneously considers clinical, morphologic, physical, psychosocial, and occupational risk factors. Methods. In the 5-year follow-up evaluation of 41 asymptomatic individuals, the risk factors for the development of lumbar disc degeneration and its progression were investigated. All 41 individuals had a magnetic resonance imaging scan at baseline and at the minimum 5-year follow-up assessment using the same scanner and protocol. The magnetic resonance images were analyzed independently by two radiologists with regard to disc degeneration. Various predictor variables were assessed both at baseline and follow-up, with special emphasis on physical job characteristics, sports activities, and magnetic resonance image–based morphologic findings. Results. Of the 41 individuals, 17 (41%) exhibited a deterioration of the disc status. In 10 individuals, the progression of disc degeneration was one grade or more. Only a weak correlation existed between progressive disc degeneration and low back pain development during a 5-year follow-up period. Multiple logistic regression analysis demonstrated that the extent of disc herniation (odds ratio [OR], 12.63; confidence interval [CI], 1.24–128.49), the lack of sports activities (OR, 2.71; CI, 1.04–7.07), and night shift work (OR, 23.01; CI, 1.26–421.31) were significant predictors for disc degeneration during follow-up evaluation when control was used for the number of degenerated discs at baseline, gender, age, and body mass index. Conclusions. The results indicate that the extent of disc herniation, the lack of sports activities, and night shift work are significant risk factors for the development of lumbar disc degeneration and its progression.

Natural History of Individuals With Asymptomatic Disc Abnormalities in Magnetic Resonance Imaging : Predictors of Low Back Pain-Related Medical Consultation and Work Incapacity

Study Design. Prospective study on individuals with asymptomatic lumbar disc abnormalities detected in magnetic resonance imaging. Objectives. To determine the natural history of asymptomatic disc abnormalities in magnetic resonance imaging and to identify predictors of future low back pain–related medical consultation and work incapacity. Summary of Background Data. The natural history of individuals with asymptomatic disc herniations has not been well established, but the high rate of lumbar disc alterations recently detected in asymptomatic individuals by magnetic resonance imaging demands reconsideration of a pathomorphology-based explanation of low back pain and sciatica. Methods. Forty-six asymptomatic individuals who had a high rate of disc herniations (73%) were observed for an average of 5 years (range, 54–72 months). Four classes of variables (medical data including magnetic resonance imaging–identified disc abnormalities, general psychological factors, physical job characteristics, and psychosocial aspects of work) were assessed at baseline and follow-up. Results. Disc herniations and neural compromise did not significantly worsen at follow-up, whereas disc degeneration progressed in 17 individuals (41.5%). Minor episodes of low back pain occurred in 19 individuals (41.3%), 6 of whom had to seek medical treatment and 5 of whom had to stop work temporarily. The requirement for low back pain–related medical consultation was predicted with high accuracy by listlessness, job satisfaction, and working in shifts (P < 0.001). Work incapacity was best predicted by physical job characteristics, job disaffection, and working in shifts (P < 0.01). Conclusion. Physical job characteristics and psychological aspects of work were more powerful than magnetic resonance imaging–identified disc abnormalities in predicting the need for low back pain–related medical consultation and the resultant work incapacity. However,the conclusions are still preliminary, and replication of the findings in larger and more representative study samples is needed.