Shigeto Nakazora

The cleavage of N-cadherin is essential for chondrocyte differentiation.

The aggregation of chondroprogenitor mesenchymal cells into precartilage condensation represents one of the earliest events in chondrogenesis. N-cadherin is a key cell adhesion molecule implicated in chondrogenic differentiation. Recently, ADAM10-mediated cleavage of N-cadherin has been reported to play an important role in cell adhesion, migration, development and signaling. However, the significance of N-cadherin cleavage in chondrocyte differentiation has not been determined. In the present study, we found that the protein turnover of N-cadherin is accelerated during the early phase of chondrogenic differentiation in ATDC5 cells. Therefore, we generated the subclones of ATDC5 cells overexpressing wild-type N-cadherin, and two types of subclones overexpressing a cleavage-defective N-cadherin mutant, and examined the response of these cells to insulin stimulation. The ATDC5 cells overexpressing cleavage-defective mutants severely prevented the formation of cartilage aggregates, proteoglycan production and the induction of chondrocyte marker gene expression, such as type II collagen, aggrecan and type X collagen. These results suggested that the cleavage of N-cadherin is essential for chondrocyte differentiation.

Tendoscopic Double-Row Suture Bridge Peroneal Retinaculum Repair for Recurrent Dislocation of Peroneal Tendons in the Ankle

Traumatic dislocation of peroneal tendons in the ankle is an uncommon lesion that mainly affects young adults. Unfortunately, most cases lead to recurrent dislocation of the peroneal tendons of the ankle (RPTD). Therefore, most cases need operative treatment. One of the most common operative procedures is superior peroneal retinaculum (SPR) repair. Recently, surgery for RPTD has been achieved with less invasive arthroscopic procedures. In this article, tendoscopic surgery for RPTD using a double-row suture bridge technique is introduced. This technique consists of debridement of the lateral aspect of the fibula under an intrasheath pseudo-cavity, suture anchor insertion into the fibular ridge, and reattachment of the SPR to the fibula using a knotless anchor screwed into the lateral aspect of the fibula. This technique mimics the double-row suture bridge technique for rotator cuff tear repair. The double-row suture bridge technique requires more surgical steps than the single-row technique, but it provides a wider bone-SPR contact surface and tighter fixation than the single-row technique. This procedure is an attractive option because it is less invasive and has achieved results similar to open procedures.

Double-Layered Lateral Meniscus Accompanied by Meniscocapsular Separation

We report an extremely rare case of double-layered lateral meniscus accompanied by meniscocapsular separation. The upper accessory meniscus was connected with the posterior horn and middle segment of the lower normal meniscus and was more mobile than the lower normal meniscus. A meniscocapsular separation was evident at the overlapping middle segment. Clinical symptoms were significantly improved by the resection of the upper accessory meniscus and the repair of the meniscocapsular separation. Careful arthroscopic analysis of other associated pathologies together with this rare abnormality was needed to achieve clinical improvement.

Endoscopic All-inside Repair of the Flexor Hallucis Longus Tendon in Posterior Ankle Impingement Patients

Longitudinal flexor hallucis longus (FHL) tendon tears are sometimes complicated by posterior ankle impingement syndrome (PAIS), especially in ballet dancers. In recent years, PAIS has been treated endoscopically, but it is difficult to suture FHL tendon tears endoscopically. In this report, we describe how to suture the FHL tendon endoscopically with the Meniscal Viper Repair system (Arthrex, Naples, FL). Without our endoscopic technique, when a patient is found to have a longitudinal tear of the FHL under endoscopy, we must choose to either neglect the tear or convert to an open repair. Open tendon suture techniques have reportedly had relatively good results but require a longer skin incision than endoscopic surgery for PAIS. Compared with the open repair, the advantages of our technique include earlier recovery, less pain, a lower rate of soft tissue complications, and improved healing through better preservation of the blood supply. This technique is an attractive and useful option because it is an easy and safe method for longitudinal FHL tendon tears.

Transverse Stress Fracture of the Proximal Patella: A Case Report.

AbstractAmong stress fractures associated with sports activities, patellar stress fracture is rare. Regarding patella stress fractures, so far only distal transverse or lateral longitudinal fractures have been reported, but there are no reports of transverse fractures occurring in the proximal patella. We describe an extremely rare case of transverse stress fracture of proximal patella in a 9-year-old athlete.A 9-year old boy, who participated in sports (sprints and Kendo) presented with left knee pain without any external injury. In plain radiographs, a fracture line was observed in the proximal 1/3 of the left patella, and a patella stress fracture was diagnosed. For treatment, because 7 months of conservative therapy showed no improvement, internal fixation was carried out using Acutrak screws, and bone union was thus achieved. Three months after the operation, he was able to return to his previous level of athletic sports activity.Regarding the mechanism of onset, it is believed that the causes are longitudinal traction force and patellofemoral contact pressure. On the other hand, the contact region of the patella with the femur changes with the flexion angle of the knee. In the current case, the fracture occurred at a site where the patella was in contact with the femur at a flexion angle of >90°, so it is believed that it occurred as a clinical condition from being subjected to repeated longitudinal traction force and patellofemoral contact pressure at a flexion angle of >90°, during the sports activities of sprints and Kendo. The nonunion of the transverse stress fracture of his proximal patella was successfully treated with internal fixation using Acutrak screws.

Use of the Tendoscopic Modified Das De Procedure for Recurrent Peroneal Tendon Dislocation

Category: Sports Introduction/Purpose: Traumatic peroneal tendon dislocation is an uncommon lesion that mainly affects young adults. It occurs most frequently during sports activities and generally during an ankle sprain. Unfortunately, most cases lead to recurrent peroneal tendon dislocation (RPTD). Therefore, most cases need operative treatments. Many surgical techniques for the treatment of RPTD have been described. One of the most popular operative procedures is the modified Das De procedure, which is the superior peroneal retinaculum (SPR) repair. Since 2014, we have performed the procedure along with tendoscopy. The purpose of this study is a preliminary report on the tendoscopic modified Das De procedure. Methods: We performed surgery for RPTD in 5 consecutive patients (4 men and 1 woman, mean age 21.4 years). All the patients were injured during sports activities. This procedure was performed with the patient in the lateral decubitus position. Two portals were made. Three anchors were inserted in the fibula. An 18-gauge needle, into which a shuttle relay had been looped (2-0 Prolene), was used to thread through the SPR. Six passes were made (Image), and the sutures were tightened in order to reattach the SPR to the fibula. A knotless anchor was screwed into the lateral aspect of the fibula to allow for suturing by using the bridge technique. For postoperative care, a short-leg cast was applied for 3 weeks. The patients were allowed partial and full weight bearing at 2 and 3 weeks, respectively. Evaluation parameters included the operation time, complications, return to regular sports activities, and recurrence. Results: The mean operation time was 88.8 minutes (range: 69–125 minutes), which was relatively longer than that of our previous open modified Das de procedure (mean: 40.0 minutes). However, compared with the initial cases, recent cases tended to have shorter surgical times. No complications occurred. All the patients could return to regular sports activities within 4 months after surgery. No recurrence was observed during the follow-up period (mean: 11.4 months; range: 9–14 months). Conclusion: The tendoscopic modified Das De procedure for RPTD required a longer operation time compared to open surgeries. However, the operation time is expected to be shortened as the surgeon gains experience. In addition, this procedure was not associated with any early severe complications and allowed patients to return to sports activities within a short period. Long-term studies involving a large number of cases are needed. However, this procedure is an attractive option because it is less invasive and has achieved similar results as those in open procedures.

Gait Analysis of Patients Suffering From Hallux Valgus

Category: Midfoot/Forefoot Introduction/Purpose: Hallux valgus that is defined as HVA (hallux valgus angle) >20 is one of the most common forefoot problems and can lead to alterations of the plantar pressure pattern. In addition, it can cause clinically gait alterations. Hence, we investigated the plantar pressure pattern and the gait-related factors using the gait analyzer. The purpose of this study was to examine the relationship between gait alterations or motor function and hallux valgus deformity. Methods: In 2009, we examined 309 inhabitants (male, 105; female, 204; age, >65 years) of Miyagawa village in Mie, Japan and compared the plantar pressure pattern between the subjects who has hallux valgus (HVA, >20; n=88) and those who does not have hallux valgus (HVA, < 20; n = 221). Furthermore, we compared gait-related factors among mild group (20< HVA < 30; n=88), moderate group (30< HVA < 40; n=24), and severe group (HVA, >40; n=9). If the right and left hallux valgus varied in severity, we selected severe side. The plantar pressure pattern and the gait-related factors such as stride, step width, foot angle (Figure 1), and gait speed were measured using the gait analyzer (Walk way MW 1000; Anima, Tokyo, Japan). Statistical analyses were performed using t-test, Chi-Square test, or logistic analysis adjusted age, gender and height. P < 0.05 was considered significant. Results: The average weight and height of hallux valgus group were significantly lower, and age of hallux valgus group were significantly higher than those of normal group. About the plantar pressure pattern, ratio of the subjects in hallux valgus group who can use the hallux ball in toe off were significantly less than those of normal group. However, the gait-related factors were not significantly different between 2 groups. On the other hand, when we compared by severity, step width tended to increase with progression of hallux valgus. Moreover, stride, gait speed, and foot angle of severe group were the lowest among 4 groups (normal, mild, moderate, and severe). Especially stride of severe group was significantly lower than those of other 3 groups. Conclusion: Mild hallux valgus can cause alterations of the plantar pressure pattern, but didn’t cause motor functional decline. However, when hallux valgus become severe, hallux valgus can cause not only gait alterations but also motor functional decline.

Endoscopic Resection for Talocalcaneal Coalition Using Posteromedial Approach: Report of Three Cases

Category: Hindfoot Introduction/Purpose: Initial treatment of symptomatic talocalcaneal coalition (TCC) is reduced activity or cast immobilization. If these conservative treatments does not relieve symptoms, surgical treatment is recommended. The operation for TCC is usually treated by an open procedure. We report the results of the three cases by endoscopic resection using posteromedial approach. Methods: Three consecutive patients (3 feet, 2 men and 1 female) who underwent surgery for TCCs were reviewed. Patient’s age at the time of surgery were 12, 13, 19 years respectively. All patients suffered from a foot pain after ankle sprain. Two patients didn’t play sports because of this pain. This operation is performed in the supine position. Two portals are each created at the proximal and distal to the vertex of the medial malleolus. Portal positions are marked by use of sonography to avoid the injury of tendons and neurovascular. By use of a shaver a radiofrequency device, as much soft tissue must be removed as possible to allow easy coalition resection, the surgeon performs sufficient resection of the coalition using an abrader until the normal articular surface can be confirmed. Movements of ankle and toes are encouraged from immediately post-operatively. Weight bearing is permitted 1 week after surgery. Results: All patients had a relief of pain. The mean preoperative and final follow-up AOFAS ankle-hind foot scale scores were from 65.3 to 92.3. Two patients returned to playing sports by three months. The mean operation time was 123 minutes (range: 97–148 minutes). However, compared with the initial cases, recent cases tended to have shorter surgical times. No complications occurred. Conclusion: A posteromedial approach for TCC is a useful technique because the advantage of allowing (1) a direct approach to both the middle- and posterior-facet coalitions without obstruction, (2) the creation of sufficient working space, (3) the obtuse insertion angle between the endoscope and instrument. On the basis of these advantage, endoscopic resection of a TCC using the posteromedial approach is considered a useful technique. To decrease the risk of neurovascular damage and tendon injury, portal positions are marked in advance by use of sonography, so that, a safe endoscopic resection of the coalition is performed.

Entrapment of Common Peroneal Nerve by Surgical Suture following Distal Biceps Femoris Tendon Repair.

We describe entrapment of the common peroneal nerve by a suture after surgical repair of the distal biceps femoris tendon. Complete rupture of the distal biceps femoris tendon of a 16-year-old male athlete was surgically repaired. Postoperative common peroneal nerve palsy was evident, but conservative treatment did not cause any neurological improvement. Reexploration revealed that the common peroneal nerve was entrapped by the surgical suture. Complete removal of the suture and external neurolysis significantly improved the palsy. The common peroneal nerve is prone to damage as a result of its close proximity to the biceps femoris tendon and it should be identified during surgical repair of a ruptured distal biceps femoris tendon.

Ultrasound Guidance in Performing a Tendoscopic Surgery to Treat Posterior Tibial Tendinitis: A Useful Tool?

A 25-year-old man with a pronation-external rotation type of fracture was surgically treated using a fibular plate. Five years later, he underwent resection of bone hyperplasia because of the ankle pain and limitation of range of motion. Thereafter, the left ankle became intermittently painful, which persisted for about one year. He presented at the age of 43 with persistent ankle pain. Physical and image analysis findings indicated a diagnosis of posttraumatic posterior tibial tendinitis, which we surgically treated using tendoscopy. Endoscopic findings showed tenosynovitis and fibrillation on the tendon surface. We cleaned and removed the synovium surrounding the tendon and deepened the posterior tibial tendon groove to allow sufficient space for the posterior tibial tendon. Full weight-bearing ambulation was permitted one day after surgery and he returned to his occupation in the construction industry six weeks after surgery. The medial aspect of the ankle was free of pain and symptoms at a review two years after surgery. Although tendoscopic surgery for stage 1 posterior tibial tendon dysfunction has been reported, tendoscopic surgery to treat posttraumatic posterior tibial tendinitis has not. Our experience with this patient showed that tendoscopic surgery is useful not only for stage 1 posterior tibial dysfunction, but also for posttraumatic posterior tibial tendinitis.