Tadanao Funakoshi

Application of Tissue Engineering Techniques for Rotator Cuff Regeneration Using a Chitosan-Based Hyaluronan Hybrid Fiber Scaffold

Background The current surgical procedures for irreparable rotator cuff tears have considerable limitations. Tissue engineering techniques using novel scaffold materials offer potential alternatives for managing these conditions. Hypothesis A chitosan-based hyaluronan hybrid scaffold could enhance type I collagen products with seeded fibroblasts and thereby increase the mechanical strength of regenerated tendon in vivo. Study Design Controlled laboratory study. Methods The scaffolds were created from chitosan-based hyaluronan hybrid polymer fibers. Forty-eight rabbit infraspinatus tendons and their humeral insertions were removed to create defects. Each defect was covered with a fibroblast-seeded scaffold (n = 16) or a non-fibroblast-seeded scaffold (n = 16). In the other 16 shoulders, the rotator cuff defect was left free as the control. At 4 and 12 weeks after surgery, the engineered tendons were assessed by histological, immunohistochemical (n = 2), and biomechanical (n = 6) analyses. Results Type I collagen was only seen in the fibroblast-seeded scaffold and increased in the regenerated tissue. The tensile strength and tangent modulus in the fibroblast-seeded scaffold were significantly improved from 4 to 12 weeks postoperatively. The fibroblast-seeded scaffold had a significantly greater tangent modulus than did the non-fibroblast-seeded scaffold and the control at 12 weeks. Conclusion This scaffold material enhanced the production of type I collagen and led to improved mechanical strength in the regenerated tissues of the rotator cuff in vivo. Clinical Relevance Rotator cuff regeneration is feasible using this tissue engineering technique.

Autologous Osteochondral Mosaicplasty for Osteochondritis Dissecans of the Elbow in Teenage Athletes

BACKGROUND Although autologous osteochondral mosaicplasty is widely used as a procedure for osteochondritis dissecans lesions, the effectiveness of this procedure in elbow lesions remains unclear. Our aim was to clarify the surgical efficacy of mosaicplasty for teenage athletes with advanced lesions of capitellar osteochondritis dissecans. METHODS From 2001 to 2006, nineteen teenage male patients who were competitive athletes and had advanced lesions of capitellar osteochondritis dissecans underwent mosaicplasties. The mean age of the patients was 14.2 years. The surgical technique involved obtaining small-sized cylindrical osteochondral grafts with a mean diameter of 3.5 mm from the lateral periphery of the femoral condyle at the level of the patellofemoral joint and transplanting the grafts (mean, 3.3 grafts) to prepared osteochondral defects. The patients were evaluated clinically and radiographically at a mean of forty-five months after surgery. RESULTS Eighteen patients were free from elbow pain, and one had mild pain occasionally. The mean total arc of elbow motion and standard deviation increased significantly from 112 degrees +/- 17 degrees preoperatively to 128 degrees +/- 12 degrees postoperatively (p < 0.005). The mean clinical score described by Timmerman and Andrews (with a maximum of 200 points) improved significantly from 131 +/- 23 points preoperatively to 191 +/- 15 points postoperatively (p < 0.0001). All patients except one had an excellent or good clinical result. All donor knees were graded as excellent on the basis of the Lysholm knee scoring system. All patients except two returned to a competitive level of the sport they had previously played. Neither loose-body formation nor secondary osteoarthritic changes were found in any patient. CONCLUSIONS The current midterm results indicate that mosaicplasty can provide satisfactory clinical outcomes for teenage athletes with advanced capitellar osteochondritis dissecans lesions.

Arthroscopic-Assisted Repair of Avulsed Triangular Fibrocartilage Complex to the Fovea of the Ulnar Head: A 2- to 4-Year Follow-up Study

PURPOSE The objective of this study was to conduct a follow-up evaluation of an arthroscopic reattachment technique using an avulsed deep component of the triangular fibrocartilage complex (dc-TFCC) from the fovea of the distal ulna (ulnar fovea). METHODS A retrospective study was performed on a consecutive cohort of 12 patients who underwent arthroscopic reattachment of the avulsed dc-TFCC into the ulnar fovea over a 24-month period. The mean age was 31 years (range, 20 to 50 years). There were 6 men and 6 women. This technique anchors the avulsed portion of the dc-TFCC to the ulnar fovea by means of a repair suture passed through the created osseous tunnel from the ulnar neck to the foveal surface. Postoperative clinical and functional outcomes were quantitatively evaluated with the Modified Mayo Wrist Score. The Disabilities of the Arm, Shoulder and Hand questionnaire served to assess each patients subjective outcome. A questionnaire regarding each patients return to his or her previous job was also completed. Radiographic evaluation was based on computed tomography and magnetic resonance imaging examinations. RESULTS At the mean follow-up of 30 months, all patients had significant reduction of wrist pain. The mean Modified Mayo Wrist Score was 92.5 ± 7.5, and all patients were rated as having excellent or good clinical results. The Disabilities of the Arm, Shoulder and Hand score significantly improved from 59.5 ± 18.5 to 7.7 ± 11.9 postoperatively (P < .0001). Of the 9 working patients, 7 returned to their previous work. Two patients had occasional extensor carpi ulnaris tendinitis after surgery. Magnetic resonance images at 12 weeks postoperatively showed findings indicating attachment of the triangular fibrocartilage complex (TFCC) to the fovea. CONCLUSIONS Arthroscopic reattachment of the avulsed TFCC to the ulnar fovea by the described technique is a valid alternative for treating avulsion of the foveal TFCC insertion.

In Vivo Visualization of Vascular Patterns of Rotator Cuff Tears Using Contrast-Enhanced Ultrasound

Background Hypoxia and decreased blood supply have been proposed as risks for tendon rupture. Visualization of the vascularity of intact and torn rotator cuffs would be useful for improving treatments for rotator cuff tear. Purpose To assess vascularity inside a tendon or an adjacent rotator cuff insertion point in patients differing in age and extent of damage to the tendon. Study Design Cross-sectional study; Level of evidence, 3. Methods Ten volunteers (all men) and 15 patients (10 men, 5 women) consented to participate in the study. Contrast agent for enhanced ultrasound was injected intravenously. Enhanced ultrasound images of the torn cuff and the contralateral shoulder were recorded for 1 minute. Four small regions of interest, the articular and bursal sides of the tendon and the medial and lateral sides of the bursa, were studied in all shoulders. Results There was a significant decrease in blood flow in the intratendinous region in elderly subjects compared with young subjects, but age had no effect on blood flow in bursal tissue. Blood flow in ruptured rotator cuffs did not differ from that in intact rotator cuffs. The intraclass correlation coefficient for intraobserver reproducibility was 0.82 (95% confidence interval: 0.77-0.86). Conclusions The findings of this investigation were the hypovascular pattern in intratendinous tissue compared with the subacromial bursa, the age-related decrease in intratendinous vascularity, and the hypovascular pattern in the tendon, regardless of rupture of the tendon. Clarification of vascular patterns inside or around the torn ends of a rotator cuff will assist in the development of successful treatments for torn rotator cuffs.

Effect of cyclic three-dimensional strain on cell proliferation and collagen synthesis of fibroblast-seeded chitosan-hyaluronan hybrid polymer fiber

BackgroundTissue engineering techniques using biodegradable three-dimensional (3D) scaffolds with cultured cells offer more potential alternatives for the treatment of severe ligament and tendon injuries. In tissue engineering, one of the crucial roles of 3D scaffolds is to provide a temporary template with the biomechanical characteristics of the native extracellular matrix (ECM) until the regenerated tissue matures. The purpose of the present study was to assess the effect of various cyclic mechanical stresses on cell proliferation and ECM production in a 3D scaffold made from chitosan and hyaluronan for ligament and tendon tissue engineering.MethodsThree-dimensional scaffolds seeded with rabbit patella tendon fibroblasts were attached to a bioreactor under various conditions: static group, no strain; stretch group, tensile strain; rotational group, rotational strain; combined group, rotational and tensile strain. In the Static group, 3 weeks of stationary culture was performed. In the remaining three groups, a loading regimen of 0.5 Hz for 18 h and then 6 h rest was carried out for 2 weeks after 1 week of static culture. The DNA content was determined to quantify cell proliferation. Real-time reverse transcription polymerase chain reaction analysis was performed to assess the mRNA levels of the ECM products.ResultsDNA content of the combined group was significantly higher than that of the static and stretch groups, and that of the rotational group was significant higher than that of the static and stretch groups at 21 days after cultivation. The mRNA level of types I and III collagen and fibromodulin in the combined group was significantly higher than that in the other three groups. The amount of collagen synthesis in the combined group was higher than that in the static group, but the difference was not significant.ConclusionsMultidimensional cyclic mechanical strain to mimic the physiological condition in vivo has the potential to improve or accelerate tissue regeneration in ligament and tendon tissue engineering using 3D scaffolds in vitro.

Autologous osteochondral mosaicplasty for osteochondritis dissecans of the elbow in teenage athletes: surgical technique.

BACKGROUND Although autologous osteochondral mosaicplasty is widely used as a procedure for osteochondritis dissecans lesions, the effectiveness of this procedure in elbow lesions remains unclear. Our aim was to clarify the surgical efficacy of mosaicplasty for teenage athletes with advanced lesions of capitellar osteochondritis dissecans. METHODS From 2001 to 2006, nineteen teenage male patients who were competitive athletes and had advanced lesions of capitellar osteochondritis dissecans underwent mosaicplasties. The mean age of the patients was 14.2 years. The surgical technique involved obtaining small-sized cylindrical osteochondral grafts with a mean diameter of 3.5 mm from the lateral periphery of the femoral condyle at the level of the patellofemoral joint and transplanting the grafts (mean, 3.3 grafts) to prepared osteochondral defects. The patients were evaluated clinically and radiographically at a mean of forty-five months after surgery. RESULTS Eighteen patients were free from elbow pain, and one had mild pain occasionally. The mean total arc of elbow motion and standard deviation increased significantly from 112° ± 17° preoperatively to 128° ± 12° postoperatively (p < 0.005). The mean clinical score described by Timmerman and Andrews (with a maximum of 200 points) improved significantly from 131 ± 23 points preoperatively to 191 ± 15 points postoperatively (p < 0.0001). All patients except one had an excellent or good clinical result. All donor knees were graded as excellent on the basis of the Lysholm knee scoring system. All patients except two returned to a competitive level of the sport they had previously played. Neither loose-body formation nor secondary osteoarthritic changes were found in any patient. CONCLUSIONS The current midterm results indicate that mosaicplasty can provide satisfactory clinical outcomes for teenage athletes with advanced capitellar osteochondritis dissecans lesions.

In vitro and finite element analysis of a novel rotator cuff fixation technique

The purpose of this investigation was to assess the biomechanic strength and stress dispersion at the repair site of surface-holding repair techniques for rotator cuff repair compared to the double-row technique. Eighteen bovine infraspinatus tendons were repaired using 3 different repair techniques: double-row repair, surface-holding repair with transosseous sutures, and surface-holding repair with knotless anchors. Biomechanical testing and two-dimensional finite element analysis were performed. The surface-holding repair with transosseous sutures provided 87.9% more stiffness than the double-row repair. The number of tendon-suture site failures of the surface-holding repair with transosseous sutures was smaller than the other 2 techniques. The finite element analysis showed that the surface-holding repair model had a more dispersing stress pattern compared to a double-row repair model. It suggests that these repair techniques can prevent high stress concentration compared to the double-row repair.

A Retrospective Evaluation of Magnetic Resonance Imaging Effectiveness on Capitellar Osteochondritis Dissecans Among Overhead Athletes

Background: Magnetic resonance imaging (MRI) has been widely used to characterize osteochondritis dissecans (OCD) lesions. However, the usefulness of MRI for predicting fragment stability in OCD of the humeral capitellum (capitellar OCD) remains unclear. Hypothesis: Preoperative MRI cannot accurately diagnose fragment instability of capitellar OCD in overhead athletes. Study Design: Cohort study (diagnosis); Level of evidence, 1. Methods: Twenty-seven male overhead athletes who had undergone surgery for capitellar OCD were included in the study. A single senior musculoskeletal radiologist blindly reviewed preoperative MRI of these OCD lesions. The radiologist reported the presence or absence of each of the 4 MRI signs indicating fragment instability as described by De Smet et al. The lesions were also classified according to the MRI staging system of Dipaola et al for characterizing the lesions. Intraoperative assessment of fragment stability was used as the gold standard. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were determined for fragment instability as assessed by MRI. Results: According to the MRI criteria by De Smet et al and the Dipaola et al staging system, 21 (78%) and 20 (74%) lesions were defined as unstable, respectively. The obtained results yielded a sensitivity of 89% and a specificity of 44% for diagnosing fragment instability using the De Smet et al MRI criteria and a sensitivity of 83% and a specificity of 44% using the Dipaola et al MRI staging system. The PPV and NPV for fragment instability were 76% and 67% using the De Smet et al criteria and 75% and 57% according to the Dipaola et al staging system, respectively. The overall correlation rate of Dipaola et al MRI and intraoperative stages was 41%. Conclusion: Preoperative MRI cannot precisely diagnose fragment instability of capitellar OCD that requires operative treatments in overhead athletes. Especially, MRI indicating stable lesions is considered not to be useful in predicting intraoperative instability of capitellar OCD in this study population.

Recovery of sensory disturbance after arthroscopic decompression of the suprascapular nerve

BACKGROUND The existence of sensory branches of the suprascapular nerve (SSN) has recently been reported, and sensory disturbance at the lateral and posterior aspect of the shoulder has been focused on as a symptom of SSN palsy. We have performed arthroscopic release of SSN at the suprascapular notch in patients with sensory disturbance since 2006. The purposes of this study were to introduce the arthroscopic surgical technique and investigate postoperative recovery of sensory disturbance. MATERIALS AND METHODS The study included 11 men and 14 women (25 shoulders), with an average age of 63.9 years (range, 41-77 years). Arthroscopic decompression of the SSN was performed using a suprascapular nerve (SN) portal as a landmark for approaching the suprascapular notch. Sensory disturbance of the shoulder was evaluated preoperatively and postoperatively. The average follow-up was 18.5 months (range, 12-30 months). RESULTS The arthroscopic procedures were performed safely. The preoperative sensory disturbance fully recovered postoperatively in all shoulders. CONCLUSION Arthroscopic release of the SSN is a useful procedure for SSN entrapment at the suprascapular notch. The sensory disturbance at the lateral and posterior aspect of the shoulder can be used as one of the criteria of diagnosing SSN palsy, especially in shoulders with massive rotator cuff tear, in which diagnosing and assessing the treatment results of associated SSN palsy is usually difficult.

Biomechanical and histologic evaluation of tissue engineered ligaments using chitosan and hyaluronan hybrid polymer fibers: a rabbit medial collateral ligament reconstruction model.

In this study, we used a rabbit medial collateral ligament reconstruction model to evaluate a novel chitosan-based hyaluronan hybrid polymer fiber scaffold for ligament tissue engineering and to examine whether mechanical forces exerted in an in vivo model increased extracellular matrix production by seeded fibroblasts. Scaffolds were used 2 weeks after incubation with fibroblasts obtained from the same rabbit in a cell-seeded scaffold (CSS) group and without cells in a noncell-seeded scaffold (NCSS) group. At 3, 6, and 12 weeks after surgery, the failure loads of the engineered ligaments in the CSS groups were significantly greater than those in the NCSS groups. At 6 weeks after surgery, the reconstructed tissue of the CSS group was positive for type I collagen, whereas that in the NCSS group was negative for type I collagen. At 12 weeks after surgery, the reconstructed tissue stained positive for type I collagen in the CSS group, but negative in the NCSS group. Our results indicate that the scaffold material enhanced the production of type I collagen and led to improved mechanical strength in the engineered ligament in vivo.