Yasuharu Tomita

Incomplete tears of the subscapularis tendon associated with tears of the supraspinatus tendon: Cadaveric and clinical studies

This study was undertaken to evaluate incomplete tears of the subscapularis tendon that occur in conjunction with small or medium-sized tears of the supraspinatus tendon. Fifty-two shoulders were examined in 26 embalmed cadavers. The average age at the time of death was 76.3 years. Rotator cuff tears were observed in 32 (61.5%) shoulders. Six (11.5%) shoulders had massive rotator cuff tears and were excluded from the study, leaving 46 shoulders for study. Twenty shoulders had a tear of the supraspinatus tendon, and 17 had a tear of the subscapularis tendon. All tears of the subscapularis tendon were articular-side incomplete tears. On histologic examination most pathologic changes of the subscapularis tendon were observed on the articular side of the upper portion. Lesions of the long head of the biceps brachii were identified in 14 (30.4%) shoulders. A statistically significant correlation was found between tears of the subscapularis tendon and the presence of lesions of the long head of the biceps brachii (P=.0014). In addition, the results of preoperative magnetic resonance imaging of 15 patients (average age, 62.9 years) with a surgically confirmed diagnosis of incomplete tears of the subscapularis tendon in conjunction with tears of the supraspinatus tendon were also evaluated. Incomplete tears of the subscapularis tendon could be identified on magnetic resonance imaging as an area of high signal intensity on axial T2-weighted images in all 15 shoulders studied.

Electromyographic analysis of shoulder joint function of the biceps brachii muscle during isometric contraction.

Surface electromyography was performed for both heads of the biceps brachii in 11 healthy men while the muscles were under 30% maximum isometric shoulder flexion and abduction. Elbow related biceps activity was minimized by using a brace locked in neutral forearm rotation. Electromyographic activity was normalized as a percentage of maximal muscle contraction during 24 shoulder motions. Electromyographic activity was detected in all motions examined, suggesting that the biceps muscle acts as a flexor and an abductor of the shoulder. Both heads of the biceps muscle had higher activities during external rotation than during internal rotation for most motions. Activities of both heads increased with arm elevation, but showed little dependence on elbow position. The long head was still active during internal rotation of the shoulder. These findings also suggest that the biceps muscle is a flexor and an abductor of the shoulder, and that the long head can act as a humeral head stabilizer in superior and anterior directions. Muscle fatigue of the biceps and the deltoid muscle also was determined at 30% of maximum isometric flexion. All muscles had significantly decreased mean power frequency and turns count, and increased amplitude and integrated electromyography. The rate of decrease in mean power frequency was larger for the biceps than for the deltoid muscle, and the rate of increase in amplitude was larger for the long head of the biceps than for the short head or for the deltoid muscle. These findings suggest that the long head of the biceps must increase its mechanical output to keep the arm in elevation to a greater extent than do the short head and the deltoid muscle. This may be one of the causes of tendinitis or rupture of the long head.

Alterations in the supraspinatus muscle belly with rotator cuff tearing: Evaluation with magnetic resonance imaging.

We studied the supraspinatus muscle in patients with full-thickness rotator cuff tearing by analyzing its architecture on magnetic resonance imaging. Forty-six shoulders with rotator cuff tears requiring surgical repair were scanned parallel to the long axis of the supraspinatus muscle. We calculated the ratio of the largest width of the supraspinatus muscle belly to the distance from the greater tuberosity to the proximal end of the supraspinatus muscle. We classified the linear bands in the supraspinatus muscle, variation in its signal intensity, and irregularity and vagueness of its margins. The larger the rotator cuff tear, the more atrophic the supraspinatus muscle became. With increased atrophy, linear bands in the suprosupinotus muscle belly increased, muscle signal intensity became less uniform, and its margins became more irregular and vague.

Experimental study of vascularized tissue-engineered bone grafts.

Background: Vascularized bone grafting has become a useful method for treatment of large bone defects and infected nonunions that lack adequate blood supply. This method has disadvantages, however, such as donor-site complications. To overcome these disadvantages, the authors developed a new method for creating vascularized tissue-engineered bone grafts in an experimental model. Methods: Fisher rat bone marrow mesenchymal stem cells were cultured for 2 weeks in fully opened, interconnected, porous hydroxyapatite ceramic. The composites of mesenchymal stem cells and hydroxyapatite were implanted in the medial calf region together with the saphenous vascular bundle in syngeneic rats. Two weeks after implantation, the vascular pedicle with the implants was exposed and covered with silicone rubber to prevent vascular invasion through surrounding tissues (vascularized mesenchymal stem cell/hydroxyapatite implants). In addition, nonvascularized mesenchymal stem cell/hydroxyapatite implants were created with a ligated vascular pedicle. Implants of vascularized hydroxyapatite alone were prepared as a control. All implants were retrieved 4 weeks after surgery. Results: Histologically, de novo bone formations were observed in the vascularized implants. This was in contrast with only necrotic tissue observed in the nonvascularized implants. Bone formation was not observed entirely in the vascularized hydroxyapatite-alone implants. For biochemical analysis, alkaline phosphatase activity and osteocalcin content of the vascularized mesenchymal stem cell/hydroxyapatite implants were significantly higher than those of the nonvascularized mesenchymal stem cell/hydroxyapatite and vascularized hydroxyapatite-alone implants. Conclusion: The results of this study indicated that the vascularized tissue-engineered bone grafts could be transferred as free vascularized grafts to lesions that lack adequate blood supply.

Avulsion of the Cartilaginous Femoral Origin of the Anterior Cruciate Ligament in a Three-year-old Child: A Case Report with a Thirteen-year Follow-up

Rupture of the anterior cruciate ligament is rarely seen in children because the ligament is stronger than the physes during childhood, meaning that trauma to the knee will more likely result in a physeal fracture1-3. DeLee and Curtis, in 1983, reported only three cases of midsubstance rupture of the anterior cruciate ligament in their study of 388 knee ligament injuries in children4. Although some recent studies have demonstrated an increasing prevalence of midsubstance rupture of the anterior cruciate ligament in children and adolescents, most of those ruptures occurred during puberty or adolescence5-7. Conversely, osteochondral avulsion fractures of the tibial origin of the anterior cruciate ligament in children are relatively common8-11. Injuries that stress the anterior cruciate ligament most often result in an osteochondral avulsion fracture of the tibial eminence. Although there have been many studies of osteochondral avulsion fracture of the tibial eminence in children, only four cases of osteochondral avulsion fracture of the femoral origin of the anterior cruciate ligament have been reported12-15. It is also known that cartilaginous avulsion fractures of the tibial eminence can occur but are very rare16,17. Furthermore, a review of the orthopaedic literature revealed only one report of an isolated cartilaginous avulsion fracture of the femoral origin18. That fracture occurred in a three-year-old boy, but the duration of follow-up was only ten weeks. Therefore, we are aware of no reports regarding the long-term effects of cartilaginous avulsion fractures of the femoral origin of the anterior cruciate ligament. It is known that residual anterior laxity occurs after an osteochondral fracture of the tibial eminence19-21. Growth disturbance is also a concern. Mylle et al. reported on the premature …

Twenty-five years followup of patients who had valgus osteotomy for arthritic hips.

We reviewed the long-term outcomes of intertrochanteric valgus femoral osteotomies in patients with arthritic hips to clarify any influencing factors. One hundred six patients (127 hips) were followed up during an average of 25 years. The average age of the patients at surgery was 42 years. The preoperative extent of degenerative change was classified radiologically into one of four grades according to the criteria of Tönnis. Radiographic measurements of acetabular coverage were made using AP radiographs obtained immediately after surgery. Thirty-eight patients (41 hips) had total hip arthroplasties; the 25-year survival rate was 69%. Radiologic evaluations of patients with mild preoperative degenerative changes (Tönnis Grade 1) improved and good clinical outcomes were obtained. In addition, radiologic evaluations of patients whose hips had better acetabular coverage (center-edge angle > 0°, sharp angle < 50°, or acetabular head index > 60%) also improved. However, radiographic measurements did not influence clinical scores. The mean score of patients younger than 50 years at surgery was higher than patients older than 50 years. The mean score of patients with unilateral hip involvement was higher than patients with bilateral involvement. Therefore, valgus osteotomies seem appropriate for younger patients with unilateral involvement.

Tear of an ossified rotator cuff of the shoulder A case report

A 57-year-old man with an ossified rotator cuff with acute tears was treated by resecting the ruptured part, as well as the ossicles, and by repairing the massive cuff defect with Teflon felt. Six years after surgery, the pain had been completely relieved, and shoulder motion and muscle strength had been recovered.

Magnetic resonance imaging of rotator cuff tearing and degenerative tendon changes: Correlation with histologic pathology

We studied degeneration of the torn rotator cuff by comparing the signal intensity of the torn tendon edge on magnetic resonance imaging with cellularity of the tendon. Fifty-one shoulders with rotator cuff tears requiring surgical repairs were scanned before surgery in a 0.5T magnetic resonance imaging system. T1-, T2-, T2*-, and proton-density-weighted sequences were obtained. Three specimens from the torn tendon edge that were obtained at operation were examined microscopically, and the number of tendon cells was calculated and averaged. Degeneration of the torn rotator cuff edge was associated with an increase in signal intensity of the torn tendon edge on T1 -, T2-, T2*, and proton-density-weighted images and a decrease in tendon cellularity. The T2-, T2*-, and proton-density-weighted images were more useful, because on the T1 -weighted image it was difficult to identify the torn cuff edge.

Four-angle radiographic assessment of cement mantle thickness in cemented total hip arthroplasty

In this study, the cement mantle thickness of 57 hips undergoing primary cemented total hip arthroplasty (THA) were investigated with 4 angle radiographs. All surgeries were performed with a standardized posterolateral surgical approach. In addition to conventional anteroposterior and lateral radiographs, obturator oblique and iliac oblique radiographs were taken. In the evaluation of the cementing grade on the anteroposterior radiograph, the incidence of hips with thin cement mantles was 25%. In evaluating the cementing grade on the anteroposterior and lateral radiographs, we found an incidence of hips with thin cement mantles of 37%. From the evaluations with 4 angle radiographs, 10 hips were additionally assigned as being of a poor cementing grade (Mulroys grade C-2). Thin cement mantles were mainly seen on the iliac oblique radiographs.