Yoshitsugu Takeda

Osteochondritis dissecans of the femoral condyle in the growth stage

The site of lesion, spontaneous healing, onset mechanism, and magnetic resonance imaging findings of 51 knees in 38 patients with osteochondritis dissecans involving the femoral condyle in the growth stage were investigated. Half of the lesions were found in the center of the lateral condyle, 1/4 were in the medial in tercondylar site, and the remaining 1/4 were in other sites. Compared with those in the other sites, the lesions in a medial intercondylar site had a lower healing rate and required a longer time to heal. T2 weighted images of the lesions showed a progression from low signal areas to the appearance of a high signal line at the fragment to parent to bone interface, to a high signal double line at the interface and parentbone surface, or to disappearance of the line. Magnetic resonance imaging often revealed discoid menisci or meniscal tears in patients with lesions in the lateral condyle, suggesting that endogenous forces play an important role in the onset of osteochondritis dissecans.

The Most Effective Exercise for Strengthening the Supraspinatus Muscle Evaluation by Magnetic Resonance Imaging

Background Electromyography has been used to determine the best exercise for strengthening the supraspinatus muscle, but conflicting results have been reported. Magnetic resonance imaging T2 relaxation time appears to be more accurate in determining muscle activation. Purpose To determine the best exercises for strengthening the supraspinatus muscle. Study Design Criterion standard. Methods Six male volunteers performed three exercises: the empty can, the full can, and horizontal abduction. Immediately before and after each exercise, magnetic resonance imaging examinations were performed and changes in relaxation time for the subscapularis, supraspinatus, infraspinatus, teres minor, and deltoid muscles were recorded. Results The supraspinatus muscle had the greatest change among the studied muscles in relaxation time for the empty can (10.5 ms) and full can (10.5 ms) exercises. After the horizontal abduction exercise the change in relaxation time for the supraspinatus muscle (3.6 ms) was significantly smaller than that for the posterior deltoid muscle (11.5 ms) and not significantly different from that of the other muscles studied. Conclusion The empty can and full can exercises were most effective in activating the supraspinatus muscle.

Conservative Treatment for Osteochondrosis of the Humeral Capitellum

Background Conservative treatment is recommended for the early stage of osteochondrosis of the humeral capitellum. However, the outcome of conservative treatment has not been well documented. Hypothesis Osteochondrosis of the humeral capitellum detected at an early stage responds well to conservative treatment. Study Design Cohort study; Level of evidence, 3. Methods We retrospectively reviewed 176 patients with osteochondrosis of the humeral capitellum. There were 134 lesions that were stage I (radiolucent area) in patients with a mean age of 11.5 years and 42 lesions that were stage II (nondisplaced fragments) in patients with a mean age of 13.9 years based on anteroposterior radiographs of the elbow in 45° of flexion. Conservative treatment was performed on 101 patients. The remaining 75 patients did not follow the authors’ advice. Conservative treatment consisted of discontinuation of heavy use of the elbow for at least 6 months. Follow-up radiographs were taken at 1 -month intervals. At a mean follow-up of 24 months, all patients were evaluated clinically and radiographically. Results Conservative management produced healing in 90.5% of stage I lesions and 52.9% of stage II lesions. The mean period required for healing was 14.9 months in stage I and 12.3 months in stage II. Sixty-six of 84 (78.6%) stage I patients and 9 of 17 (52.9%) stage II patients returned to competitive-level baseball. Of the 75 patients who did not follow our advice, healing was observed in 17 (22.7%). The healing rate was higher for the 101 patients who followed our advice as opposed to the 75 patients who did not. Conclusion Osteochondrosis of the humeral capitellum can be successfully treated conservatively if treatment is begun in an early stage of the disease.

In Vivo Magnetic Resonance Imaging Measurement of Tibiofemoral Relation With Different Knee Flexion Angles After Single- and Double-Bundle Anterior Cruciate Ligament Reconstructions

PURPOSE Double-bundle anterior cruciate ligament (ACL) reconstruction has been shown to restore better kinematics in vitro, but it is uncertain whether this technique can achieve this in vivo. We investigated whether anatomic double-bundle ACL reconstruction can restore a better tibiofemoral relation in the sagittal plane under static unloading conditions. METHODS The tibiofemoral relation was assessed with an open magnetic resonance imaging scanner (0.5 T) in 15 patients with anatomic double-bundle reconstruction (double-bundle group) and 14 patients with single-bundle reconstruction (single-bundle group) by use of hamstring tendons. T1-weighted magnetic resonance imaging for both knees was obtained at 0 degrees, 45 degrees, 90 degrees, and 120 degrees of flexion without external force and muscle contraction 6 months after surgery. The position of the posterior femoral condyles relative to the tibia was measured in the midmedial and midlateral sagittal sections of the knee. Clinical evaluation (range of motion, KT-2000 measurement [MEDmetric, San Diego, CA], and pivot-shift test) was performed at the same time. RESULTS KT-2000 testing showed that the mean side-to-side difference in the double-bundle group (0.7 mm) was significantly smaller than that in the single-bundle group (1.7 mm). In the double-bundle group, the tibiofemoral relation in operated knees was not significantly different from that in the contralateral knees at 0 degrees, 45 degrees, 90 degrees, and 120 degrees of flexion, although at 0 degrees of flexion, the femoral condyles were positioned anteriorly relative to the tibia compared with that in the contralateral knees. Similar results were obtained in the single-bundle group. The difference in the tibiofemoral relation between reconstructed and contralateral knees was not significantly different between the 2 groups. CONCLUSIONS According to KT-2000 measurement, this study found that anteroposterior stability was better with anatomic double-bundle ACL reconstruction than with single-bundle ACL reconstruction. However, under static conditions without an anterior drawer force, anatomic double-bundle ACL reconstruction did not show superiority in terms of restoring a better tibiofemoral relation compared with single-bundle ACL reconstruction. LEVEL OF EVIDENCE Level III, comparative study.

Hamstring muscle function after tendon harvest for anterior cruciate ligament reconstruction: evaluation with T2 relaxation time of magnetic resonance imaging.

Background Regeneration of the semitendinosus and gracilis tendons after harvesting for anterior cruciate ligament reconstruction has been reported; however, muscle belly function after tendon regeneration has not been well documented. Hypothesis The semitendinosus and gracilis muscles are highly activated during knee flexion if their tendons are well regenerated after anterior cruciate ligament reconstruction. Study Design Descriptive laboratory study. Methods Hamstring muscle activation in 11 patients who had undergone anterior cruciate ligament reconstruction with semitendinosus and gracilis tendons was evaluated by measuring the increase of T2 relaxation time measured via magnetic resonance imaging after knee flexion exercise. Tendon regeneration was evaluated via magnetic resonance imaging. Results Both muscles increased T2 relaxation time after knee flexion exercise in the operated legs, and there was no significant difference in those values between the operated and nonoperated legs. All the semitendinosus tendons were regenerated at or below the joint line, but no gracilis tendons were observed beyond the joint line. The results indicated that both muscles were highly recruited during knee flexion, regardless of the degree of their tendon regeneration. Conclusion The semitendinosus and gracilis muscles are able to restore or maintain their contractile capability after harvest of their tendons for anterior cruciate ligament reconstruction, regardless of the degree of regeneration.

Validity of arthroscopic measurement of glenoid bone loss using the bare spot

Purpose Our aim was to test the validity of using the bare spot method to quantify glenoid bone loss arthroscopically in patients with shoulder instability. Methods Twenty-seven patients with no evidence of instability (18 males, nine females; mean age 59.1 years) were evaluated arthroscopically to assess whether the bare spot is consistently located at the center of the inferior glenoid. Another 40 patients with glenohumeral anterior instability who underwent shoulder arthroscopy (30 males, ten females; mean age 25.9 years) were evaluated for glenoid bone loss with preoperative three-dimensional computed tomography (3D-CT) and arthroscopic examination. In patients without instability, the distances from the bare spot of the inferior glenoid to the anterior (Da) and posterior (Dp) glenoid rim were measured arthroscopically. In patients with instability, we compared the percentage glenoid bone loss calculated using CT versus arthroscopic measurements. Results Among patients without instability, the bare spot could not be identified in three of 27 patients. Da (9.5±1.2 mm) was smaller than Dp (10.1±1.5 mm), but it was not significantly different. However, only 55% of glenoids showed less than 1 mm of difference between Da and Dp, and 18% showed more than 2 mm difference in length. The bare spot could not be identified in five of 40 patients with instability. Pearson’s correlation coefficient showed significant (P<0.001) and strong (R2=0.63) correlation in percentage glenoid bone loss between the 3D-CT and arthroscopy method measurements. However, in ten shoulders (29%), the difference in percentage glenoid bone loss between 3D-CT and arthroscopic measurements was greater than 5%. Conclusion The bare spot was not consistently located at the center of the inferior glenoid, and the arthroscopic measurement of glenoid bone loss using the bare spot as a landmark was inaccurate in some patients with anterior glenohumeral instability. Level of evidence Level II, prospective comparative study.

Diagnostic Value of the Supine Napoleon Test for Subscapularis Tendon Lesions.

PURPOSE The purpose of this study was to compare the diagnostic value of the supine Napoleon test (a variation of the belly-press test that reduces compensatory motion) with other clinical tests for subscapularis tendon (SSC) tears. METHODS One hundred thirty consecutive patients who were scheduled for arthroscopic rotator cuff repair were evaluated preoperatively with the lift-off test, Napoleon test, bear-hug test, and supine Napoleon test. The supine Napoleon test was performed by placing the patients hand on their belly while they lay supine with an examiner holding their hand and shoulder to prevent compensatory motion. The patient was asked to move their elbow upward and the test was considered positive if they were unable to do so. During surgery, SSC lesions were classified with the Lafosse classification system. Sensitivity, specificity, accuracy, and positive and negative likelihood ratios (LR+, LR-) were calculated for each test. The ability to detect partial SSC tears was compared among the clinical tests. RESULTS Fifty-two of 130 patients (40%) had SSC tears confirmed arthroscopically. For diagnosis of these tears, the supine Napoleon test was the most sensitive (84%), followed by the bear-hug test (74%), and the bear-hug test was the most specific (97%), followed by the supine Napoleon test (96%). The LR+ was greatest for the bear-hug test (28.4) and next greatest for the supine Napoleon test (21.9). The LR- was lowest for the supine Napoleon test (0.16) and the bear-hug test was second (0.27). The sensitivity of the supine Napoleon test (65%) was highest for detecting partial tears. CONCLUSIONS In comparison with other clinical tests for SSC tears, the supine Napoleon test had the greatest diagnostic value for full-thickness SSC tears and was most able to detect partial tears. LEVEL OF EVIDENCE Level III, diagnostic nonrandomized study.

Development of secondary ossification centres of the acromion in Japanese youth: a computed tomographic study

Purpose. To determine the age range when the secondary ossification centres of the acromion appear and fuse in Japanese youth using computed tomography (CT). Methods. CT scans of 85 shoulders in 35 male and 14 female consecutive patients aged 6 to 20 (mean, 16) years were reviewed. No patient had pain or tenderness at the acromion. Appearance and fusion of the secondary ossification centres of the acromion were determined twice by an orthopaedist. A secondary ossification centre was considered to have appeared when a low-density line was noted at the juxta-epiphyseal area and to have fused when the line had disappeared. Intra-observer reliability was determined. Results. The intra-observer reliability was 0.93. The secondary ossification centres of the acromion had appeared at around 10 years of age and had fused at around 15 years of age, with one exception. Conclusion. In these Japanese subjects, the secondary ossification centres of the acromion had appeared at around 10 years of age and had fused at 15 to 16 years.

Arthroscopic Removal of a Wire Fragment from the Posterior Septum of the Knee following Tension Band Wiring of a Patellar Fracture

Tension band wiring with cerclage wiring is most widely used for treating displaced patellar fractures. Although wire breakage is not uncommon, migration of a fragment of the broken wire is rare, especially migration into the knee joint. We describe here a rare case of migration of a wire fragment into the posterior septum of the knee joint after fixation of a displaced patellar fracture with tension band wiring and cerclage wiring. Although it was difficult to determine whether the wire fragment was located within or outside the knee joint from the preoperative plain radiographs or three-dimensional computed tomography (3D CT), we found it arthroscopically through the posterior transseptal portal with assistance of intraoperative fluoroscopy. Surgeons who treat such cases should bear in mind the possibility that wire could be embedded in the posterior septum of the knee joint.