Christian W. A. Pfirrmann

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.

Clinical Outcome After Structural Failure of Rotator Cuff Repairs

Background: The clinical outcome for patients with documented rerupture after open repair of one or more rotator cuff tendons is not well known. The purpose of this study was to evaluate the clinical outcomes of a consecutive series of rotator cuff reruptures after repair and to provide information concerning the advisability of rotator cuff repair in situations in which there may be a high probability of rerupture. Methods: During prospective follow-up after rotator cuff repairs, we detected, with magnetic resonance imaging, structural failure of the repair in twenty patients, who had a mean age of fifty-nine years at the time of the rotator cuff repair. All patients were clinically examined for the purpose of this report at a mean of thirty-eight months. Results: The reruptures invariably involved the originally torn tendon but were smaller than the original tear in sixteen of the twenty patients. Fatty degeneration of the supraspinatus and infraspinatus muscles, atrophy of the supraspinatus muscle, and glenohumeral osteoarthritis progressed significantly from the preoperative state (p < 0.05). At the time of the most recent follow-up, the subjective shoulder value averaged 75 percent of the value for a normal shoulder. Eleven patients were very satisfied with the result, six were satisfied, two were disappointed, and one was dissatisfied. The mean relative score according to the system of Constant and Murley had increased from 49 percent of the score for a normal shoulder preoperatively to 83 percent postoperatively (p = 0.0001). Pain had decreased significantly, and the ranges of active, pain-free forward elevation and abduction as well as the abduction strength had improved significantly (p < 0.05). The clinical outcome was significantly correlated with the size of the postoperative tear, the stage of postoperative fatty muscle degeneration of the infraspinatus and subscapularis, the postoperative acromiohumeral distance, and the degree of postoperative glenohumeral osteoarthritis (p < 0.05). Conclusions: This study documents that an attempt at rotator cuff repair significantly decreases pain (p = 0.0026) and significantly improves function (p = 0.0005) and strength (p = 0.0137) even if magnetic resonance imaging documents that the repair has failed. This finding suggests that the potential for rerupture should not be considered a formal contraindication to an attempt at repair if optimal functional recovery is the goal of treatment.

Long-term outcome after structural failure of rotator cuff repairs.

BACKGROUND In a previous study, twenty consecutive patients with a rerupture of the rotator cuff, as documented with magnetic resonance imaging, were found to have significantly less pain and better function and strength, compared with the preoperative state, at 3.2 years postoperatively. It was the purpose of this study to determine the clinical and structural outcomes of these reruptures in the same twenty patients after a longer period of follow-up. METHODS At a mean of 7.6 years postoperatively, the twenty patients were reexamined clinically and with standard radiographs and magnetic resonance imaging with use of the same clinical, radiographic, and magnetic resonance imaging criteria as were utilized in the review at 3.2 years. The mean age at the time of final follow-up was sixty-six years. RESULTS Nineteen of the twenty patients continued to be either very satisfied or satisfied with the outcome. The relative Constant score averaged 88% and was not significantly different from the score at 3.2 years, which averaged 83%. The mean scores for pain, function, and strength also had not changed significantly. Overall, the twenty reruptures had not increased in size, and eight of them had healed structurally at the time of the 7.6-year follow-up. Seven of these eight reruptures had been of the supraspinatus tendon only, and seven had been smaller than 400 mm(2) at 3.2 years. Twelve reruptures persisted, and five were larger than the preoperative tear. Fatty infiltration of the infraspinatus muscle progressed significantly (p = 0.015) and the acromiohumeral distance decreased significantly (p = 0.006) between the two follow-up periods. Neither fatty infiltration of the supraspinatus and subscapularis muscles nor glenohumeral osteoarthritis progressed significantly. CONCLUSIONS At an average of 7.6 years, the clinical outcomes after structural failure of rotator cuff repairs remained significantly improved over the preoperative state in terms of pain, function, strength, and patient satisfaction. Overall, the reruptures that had been present at 3.2 years did not increase in size. We also found that reruptures of the supraspinatus that had been smaller than 400 mm(2) had the potential to heal.

Clinical and structural outcomes of nonoperative management of massive rotator cuff tears.

BACKGROUND The natural history of massive rotator cuff tears is not well known. The purpose of this study was to determine the clinical and structural mid-term outcomes in a series of nonoperatively managed massive rotator cuff tears. METHODS Nineteen consecutive patients (twelve men and seven women; average age, sixty-four years) with a massive rotator cuff tear, documented by magnetic resonance imaging, were identified retrospectively. There were six complete tears of two rotator cuff tendons and thirteen complete tears of three rotator cuff tendons. All patients were managed exclusively with nonoperative means. Nonoperative management was chosen when a patient had low functional demands and relatively few symptoms and/or if he or she refused to have surgery. For the purpose of this study, patients were examined clinically and with standard radiographs and magnetic resonance imaging. RESULTS After a mean duration of follow-up of forty-eight months, the mean relative Constant score was 83% and the mean subjective shoulder value was 68%. The score for pain averaged 11.5 points on a 0 to 15-point visual analogue scale in which 15 points represented no pain. The active range of motion did not change over time. Forward flexion and abduction averaged 136 degrees; external rotation, 39 degrees; and internal rotation, 66 degrees. Glenohumeral osteoarthritis progressed (p = 0.014), the acromiohumeral distance decreased (p = 0.005), the size of the tendon tear increased (p = 0.003), and fatty infiltration increased by approximately one stage in all three muscles (p = 0.001). Patients with a three-tendon tear showed more progression of osteoarthritis (p = 0.01) than did patients with a two-tendon tear. Four of the eight rotator cuff tears that were graded as reparable at the time of the diagnosis became irreparable at the time of final follow-up. CONCLUSIONS Patients with a nonoperatively managed, moderately symptomatic massive rotator cuff tear can maintain satisfactory shoulder function for at least four years despite significant progression of degenerative structural joint changes. There is a risk of a reparable tear progressing to an irreparable tear within four years.

Measurement of glenoid version: conventional radiographs versus computed tomography scans

Glenoid version seems to play an important role in the stability and loading of the glenohumeral joint. The purpose of this study was to compare measurements of glenoid version on axillary views and computed tomography (CT) scans. Radiographs and CT scans of 25 patients evaluated predominantly for glenohumeral joint instability and 25 patients after implantation of a total shoulder prosthesis were analyzed by 3 independent observers. In all patients glenoid version was determined on an axillary view and on a CT scan at the mid-glenoid level. The mean glenoid version measured on CT scans was 3 degrees of retroversion in the instability group (range, 7 degrees of anteversion to 16 degrees of retroversion) and 2 degrees of anteversion in the total shoulder prosthesis group (range, 16 degrees of anteversion to 23 degrees of retroversion). Glenoid retroversion was overestimated on plain radiographs in 86%. The mean difference between measurements of glenoid version on axillary views and CT cuts was 6.5 degrees (range, 0 degrees -21 degrees ), and the coefficient of correlation between these measurements was 0.33 in the instability group and 0.67 in the prosthesis group. In conclusion, glenoid version cannot be determined accurately on standard axillary radiographs, either preoperatively or postoperatively. Studies that assess the role of glenoid component orientation should use a reproducible method of assessment such as CT.

Trochleaplasty for patellar instability due to trochlear dysplasia: A minimum 2-year clinical and radiological follow-up of 19 knees.

Background Recurrent patellar dislocation may be associated with trochlear dysplasia. Trochleaplasty is a surgical procedure which strives to deepen the trochlear groove. We evaluated the clinical and radiological effect of trochleaplasty after a minimum follow-up of 2 years. Patients and methods We examined 19 knees in 16 patients at a mean of 3 years after trochleaplasty. Postoperatively, a subjective questionnaire, a Kujala score, and tests for potential patellar redislocation and apprehension were evaluated. On radiographs we evaluated the preoperative and postoperative crossing sign, trochlear depth, trochlear bump, and patellar height. On CT scans, the pre- and postoperative tibial tuberosity to trochlear groove distance (TTTG) and the patellar inclination angle were measured. Results 16 of 19 knees improved subjectively. The Kujala score increased from 56 to 80 points at the latest follow-up. None of the patients sustained a redislocation. 5 patients had medial parapatellar tenderness, including 4 with persistent apprehension. Radiological signs of trochlear dysplasia were corrected. Interpretation Patellofemoral instability with underlying trochlear dysplasia can be treated successfully by trochleaplasty.

Association Between Rotator Cuff Abnormalities and Reduced Acromiohumeral Distance

OBJECTIVE The purpose of this study was to evaluate the association between rotator cuff abnormalities and reduced acromiohumeral distance. MATERIALS AND METHODS Acromiohumeral distance was measured on conventional radiographs and on MR images. Three age- and sex-matched patient groups each including 21 patients were stratified according to acromiohumeral distance on conventional radiographs (group 1, <or= 7 mm; group 2, 8-10 mm; group 3, > 10 mm). Acromiohumeral distance was related to the presence, location, and size of a rotator cuff tear and the degree of fatty degeneration of the muscle assessed on MR arthrography. The relative influence on acromiohumeral distance of the various MR arthrographic findings was assessed. Spearmans rank correlation and stepwise regression were used for statistical analysis. RESULTS In group 1 (acromiohumeral distance <or= 7 mm) full-thickness supraspinatus tendon tears were present in 90% (19/21) of the patients, infraspinatus tendon tears in 67% (14/21) of the patients, and subscapularis tendon tears in 43% (9/21) of the patients. The size of rotator cuff tendon tears and the degree of fatty degeneration in all rotator cuff muscles showed a significant negative correlation with acromiohumeral distance (p < 0.05). After stepwise regression, a significant relative influence on acromiohumeral distance remained for size of rotator cuff tear (p < 0.0001) and for degree of fatty degeneration of the infraspinatus muscle (p = 0.013). CONCLUSION Tendon tears and fatty muscle degeneration in the rotator cuff correlate with reduced acromiohumeral distance. Size of rotator cuff tear and degree of fatty degeneration of the infraspinatus muscle have the most pronounced influence on acromiohumeral distance.

Prevalence of cam-type deformity on hip magnetic resonance imaging in young males: a cross-sectional study.

To determine the prevalence of cam‐type deformities on hip magnetic resonance imaging (MRI) in young males.

How Useful Is the Alpha Angle for Discriminating between Symptomatic Patients with Cam-type Femoroacetabular Impingement and Asymptomatic Volunteers?

PURPOSE To compare the alpha-angle measurements in volunteers and patients with femoroacetabular impingement (FAI) and to develop potential threshold values. MATERIALS AND METHODS This study was approved by the institutional review board; all individuals signed informed consent. Magnetic resonance (MR) images at 1.5 T in 106 individuals (ages 20-50 years) were analyzed in 53 patients (33 cam- and 20 mixed-type FAI) and 53 age- and sex-matched asymptomatic volunteers. Alpha angles were measured on radially reformatted MR images of the proximal femur by two independent readers. Intraclass correlation coefficient (ICC) and receiver operating characteristic (ROC) were calculated. RESULTS Mean alpha angles were highest in the anterosuperior segment: 65.4° ± 11.5 [standard deviation] and 65.2° ± 7.3 for readers 1 and 2 in patients and 53.3° ± 9.6 and 55.0° ± 8.8 in volunteers, respectively (P < .001, patients vs volunteers). Alpha angles greater than 55° were measured in 20 (38%) and 33 (62%) of 53 volunteers for readers 1 and 2, respectively. Maximal alpha angle in any segment was substantially different (P < .001) in patients and volunteers (70.3° ± 11.2 vs 57.9° ± 10.5 for reader 1; 69.4° ± 8.8 vs 58.7° ± 8.9 for reader 2), with a large overlap. Overall interobserver agreement was good (ICC, 0.712). ROC showed the largest area under the curve at the anterosuperior segment: 0.791 and 0.824 for readers 1 and 2, respectively (P < .001). A 55° alpha-angle threshold value gave a sensitivity and specificity of 81% and 65% for reader 1 and of 90% and 47% for reader 2, respectively. A 60° alpha-angle threshold value gave a sensitivity and specificity of 72% and 76% for reader 1 and 80% and 73% for reader 2, respectively. CONCLUSION There is substantial overlap in the alpha-angle measurements between volunteers and patients with cam-type deformities. Discrimination is best at the anterosuperior segment. Increasing the alpha-angle threshold value from 55° to 60° reduces false-positive results while maintaining a reasonable sensitivity.

Elbow Nerves: MR Findings in 60 Asymptomatic Subjects—Normal Anatomy, Variants, and Pitfalls

PURPOSE To prospectively evaluate the signal intensity (SI), course, and diameter of elbow nerves and to identify anatomic variants that are potentially associated with nerve compression syndromes on magnetic resonance (MR) images of asymptomatic elbows. MATERIALS AND METHODS This study was approved by the institutional review board. Informed consent was obtained from each volunteer. Sixty subjects with asymptomatic elbows (age range, 22.4-51.7 years; median age, 32.8 years) underwent MR imaging. Increased SI compared with surrounding muscles on fluid-sensitive MR images, anatomic course, anatomic nerve and muscle variants potentially associated with nerve compression syndromes, and qualitative changes in nerve diameters were evaluated. Quantitative data on the shortest and longest nerve diameters were obtained. RESULTS Increased SI on fluid-sensitive MR images was seen in the ulnar nerve in 60% (36 of 60) of subjects but was never observed in the median and radial nerves. An atypical intermuscular course of the median nerve between the brachialis and pronator muscles was detected in 17% (10 of 60) of subjects. Ulnar nerve subluxation at the level of the cubital tunnel was seen in 2% (one of 60) of subjects; an anconeus epitrochlearis muscle, in 23% (14 of 60); and a hypertrophic leash of Henry, in 15% (nine of 60). Median nerve dimensions were 2.4 x 4.0 mm (range, 1.0-4.0 x 3.0-7.0 mm) for the ulnar nerve, 1.0 x 1.9 mm (range, 0.8-2.0 x 0.9-5.0 mm) for the radial nerve, and 3.0 x 5.4 mm (range, 1.0-5.0 x 3.0-9.0 mm) for the median nerve. CONCLUSION Increased SI of the ulnar nerve on fluid-sensitive images (60%), an atypical intermuscular course of the median nerve (17%), and an anconeus epitrochlearis muscle (23%) are common MR findings in asymptomatic elbows.