A Scaffold-Free Allogeneic Construct From Adipose-Derived Stem Cells Regenerates an Osteochondral Defect in a Rabbit Model.

PURPOSE: To determine whether an osteochondral defect could be healed histologically by implanting allogeneic 3-dimensionally formed adipose-derived stem cells (ADSCs) in a rabbit model. METHODS: Thirty Japanese white rabbits (aged 15-17 weeks) were assigned to 1 of 2 groups. An osteochondral defect (diameter, 4.8 mm; depth, 3 mm) was created in the trochlear groove of the knee using a drill. The defects were left empty in the control group and were filled with cylindrical plugs of allogeneic ADSCs extracted from adipose tissue in the experimental group. Macroscopic scoring, histologic scoring, and immunohistologic stainability of type II collagen were evaluated at 4, 8, and 12 weeks postoperatively. RESULTS: The macroscopic scores of the healing tissue in the experimental group were significantly greater than those in the control group at 12 weeks (P = .031). Histologically, safranin O staining was noted at 4 weeks and increased gradually over time in the experimental group. The modified International Cartilage Repair Society histologic score in the experimental group was significantly higher than that in the controls at 8 and 12 weeks (14 vs 9 at 8 weeks [P = .008], 18 vs 10 at 12 weeks [P = .007]). The implanted tissue was positive for type II collagen, and stainability increased gradually over time. CONCLUSIONS: The 3-dimensional scaffold-free allogeneic ADSCs implanted into the osteochondral defect survived, adhered to the defect, increased the stainability of type II collagen gradually over time, and promoted histologic healing in a rabbit model. CLINICAL RELEVANCE: ADSC implantation designed to promote osteochondral healing may play an important role in osteochondral healing.

Scaffold-Free Tissue-Engineered Allogenic Adipose-Derived Stem Cells Promote Meniscus Healing.

PURPOSE: To determine whether meniscal tissue could be healed histologically by the implantation of allogenic three-dimensional formed adipose-derived stem cells (ADSCs) in a rabbit model of partial meniscectomy. METHODS: Forty Japanese white rabbits (aged 15-17 weeks) were assigned to 2 groups. Defects 1.5 mm in diameter were created in the anterior horn of the medial menisci. The defects were left empty in the control group and were filled with cylindrical plugs of allogenic ADSCs extracted from adipose tissue in the experimental group. Macroscopic scoring (range, 0-3), histological scoring (range, 0-12), and immunohistological stainability of type I collagen were evaluated at 2, 4, 8, and 12 weeks postoperatively (n = 5 rabbits for each week). RESULTS: Macroscopically, the height of the healing tissue in the experimental group was significantly greater than that of the control group at 2 weeks (3 vs 0, P = .01), 4 weeks (3 vs 1, P = .01), and 8 weeks (3 vs 2, P = .02). Histologically, safranin-O staining was noted at 2 weeks and increased gradually over time in the experimental group. In contrast, the intensity of staining was lower in controls at all weeks. Tissue quality scores were significantly higher in the experimental group than in the controls at all weeks (3 vs 0 at 2 weeks [P = .00009], 4.5 vs 2 at 4 weeks [P = .00023], 9 vs 5 at 8 weeks [P = .0047], 10.5 vs 6 at 12 weeks [P = .00026]). The implanted tissue was positive for type I collagen, and stainability was increased gradually over time. CONCLUSIONS: Three-dimensional scaffold-free allogenic ADSCs implanted into a 1.5-mm avascular meniscal defect survived, adhered to the defect, and promoted histological meniscus healing in a rabbit model. CLINICAL RELEVANCE: ADSC implantation designed to promote meniscal healing may play an important role as a tool for meniscus healing.

Relationship between the skeletal maturation of the distal attachment of the patellar tendon and physical features in preadolescent male football players.

PURPOSE: The aim of this study was to compare ultrasonography stages of the tibial tuberosity development and physical features. METHODS: This study examined 200 knees in 100 male football players aged 10-15 years. Tibial tuberosity development on ultrasonography was divided into 3 stages: Sonolucent stage (stage S), Individual stage (stage I), and Connective stage (stage C). Age, height, quadriceps and hamstring muscle tightness, and muscle strength in knee extension and flexion were determined. These findings were compared with the respective stages of development. RESULTS: The tibial tuberosity was stage S in 27 knees, stage I in 69 knees, and stage C in 104 knees, with right and left sides at the same stage in 95 %. Average age and height significantly increased with advancing tibial tuberosity development. Quadriceps tightness increased with tibial tuberosity development. Hamstring tightness decreased with development. The strength of both knee extension and flexion increased with advancing development, with a greater change seen in knee extension, hamstring/quadriceps ratio: stage C, 0.74; stage A, 0.64; stage E, 0.53. CONCLUSIONS: Osgood-Schlatter pathogenesis reportedly involves increased quadriceps tightness with rapidly increasing femoral length during tibial tuberosity development. In this study, it was confirmed that quadriceps tightness increased, yet hamstring tightness decreased, suggesting that quadriceps tightness is not due to femoral length alone. Other factors, including muscle strength, may be involved. The study shows that thigh muscle tightness and thigh muscle performance change with the skeletal maturation of the distal attachment of the patellar tendon. These results add new information to the pathogenesis of Osgood-Schlatter disease.

Roles of ACL remnants in knee stability.

PURPOSE: This study evaluated knee laxity in anterior tibial translation and rotation following removal of anterior cruciate ligament (ACL) remnants using a computer navigation system. METHODS: This prospective study included 50 knees undergoing primary ACL reconstruction using a navigation system. ACL remnants were classified into four morphologic types: Type 1, bridging between the roof of the intercondylar notch and tibia; Type 2, bridging between the posterior cruciate ligament and tibia; Type 3, bridging between the anatomical insertions of the ACL on the lateral wall of the femoral condyle and the tibia; and Type 4, no bridging of ACL remnants. Anterior tibial translation and rotatory laxity were measured before and after remnant resection using a navigation system at 30°, 60°, and 90° of knee flexion. The amount of change in anterior tibial translation and rotatory laxity of each type was compared among the types. RESULTS: The different morphologic types of ACL remnants were as follows: Type 1, 15 knees; Type 2, 9 knees; Type 3, 6 knees; and Type 4, 20 knees. The amount of change in anterior tibial translation and rotatory laxity at 30° knee flexion in Type 3 was significantly larger than in the other types. There were no significant differences in either tibial translation or rotatory laxity at 60° and 90° knee flexion among the types. CONCLUSIONS: In Type 3, ACL remnants contributed to anteroposterior and rotatory knee laxity evaluated at 30° knee flexion. The bridging point of the remnants is important to knee laxity. The Type 3 remnant should be preserved as much as possible when ACL reconstruction surgery is performed. LEVEL OF EVIDENCE: Prognostic study, level II.

Outcomes and failure factors in surgical treatment for osteochondritis dissecans of the capitellum.

BACKGROUND: Osteochondritis dissecans (OCD) of the capitellum is an intra-articular lesion and one of the leading causes of permanent elbow disability. The treatment of advanced capitellar OCD remains challenging because of the limited potential of the articular cartilage for self-repair. The purpose of this study was to investigate the outcome of surgical treatment for OCD of the capitellum. METHODS: From 2000 to 2010, 32 male patients who had advanced lesions of capitellar OCD were treated operatively. The mean age of the patients was 14.4 years at the time of surgery. Twenty-nine patients played baseball and 3 played other sports. The lesions were of the centralized type in 9 patients, the lateral type in 4 patients, and the widespread type in 19 patients. For the surgical procedure, osteochondral peg fixation was selected for 13 patients and osteochondral autograft transplantation for 19 patients. Clinical outcome was measured with the elbow rating system including range of motion, and the number of patients who returned to active sports participation within 1 year after surgery was determined. RESULTS: The mean total arc of elbow motion increased from 123±17 degrees preoperatively to 132±14 degrees postoperatively. The mean clinical score improved significantly from 133±24 to 177±27. Within the first year after surgery, 81.3% of the patients returned to active sports playing. However, 4 of 8 patients (50%) in which osteochondral peg fixation was performed for lesions of the lateral widespread type required reoperation. CONCLUSIONS: Our results indicate that osteochondral peg fixation and osteochondral autograft transplantation may improve elbow rating score, and may facilitate a return to active sports participation. However, osteochondral peg fixation may be insufficient for lesions of the widespread type because of their poor stability. The large lateral condyle lesions had a worse outcome, and future studies will need to develop improved treatment for these defects. LEVEL OF EVIDENCE: Level IV (case series).

Epidemiology of trauma-related paediatric limb fracture using a unique classification: A 10-year retrospective, single-centre study.

INTRODUCTION: Research regarding the epidemiology of paediatric trauma is limited. Using our unique classification, we describe paediatric trauma cases in a 10-year single-centre study to improve paediatric care. MATERIALS AND METHODS: Data regarding all paediatric trauma cases were extracted using a computerised medical record system that detected fracture diagnosis and epiphyseal injury. Registry search identified cases from January 2008 to December 2017. Age, sex, type of fracture, and details of injury mechanism were analysed, and we categorised the 'falls/turnover' mechanism using a new trauma energy classification based on speed and height. RESULTS: A total of 1379 cases (953 boys and 426 girls) were included. The highest number of injuries (553 cases, 40%) was seen in school children (aged 6 to 10 years). Forearm fracture occurred most frequently, followed by humeral fracture. The most frequent injury mechanism in falls/turnover (969 cases, 70%) was sports in 272 cases (28%), playground equipment in 179 cases (18%), furniture in 102 cases (11%), and bicycling in 87 cases (9%). We classified 956 cases of falls/turnover using our trauma energy classification scheme. Most cases (29%) were classified into the L2 category (low height and high speed), followed by the L1 category (low height and low speed) (p < 0.01). Subcategory analysis using the classification revealed that younger children were more likely to be injured by falling from high places because of their physique, whereas older children were more likely to be injured by a turnover from lower places and at higher speed. CONCLUSION: We describe the epidemiology of fractures in detail and present a new classification system, which may aid in understanding the injury mechanism independent of children's height. The fact that paediatric fractures occur at relatively low energy levels and are trended by age, activity, and sex, could be of potential universal use for their prevention and parent education.

Conscious performance and arthroscopic findings in athletes with anterior cruciate ligament injuries treated via conservative therapy during the competitive season.

PURPOSE: Athletes often receive conservative treatment for injured anterior cruciate ligaments (ACLs) so that they can continue to play to the end of their season. The purpose of this study was to examine the conscious performance and arthroscopic findings of athletes who received conservative therapy for ACL injuries. METHODS: Forty-two patients with ACL injuries underwent conservative treatment. After the season ended, ACL reconstruction was performed. We examined the following parameters: (1) time required for return to competition after injury, (2) conscious performance after return to competition, (3) whether the injured knee gave way during conservative therapy or after return to competition, and (4) cause of performance deterioration if applicable. To determine conscious performance, patients were asked to rate their performance after therapy relative to their performance before injury. RESULTS: Thirty-eight of the 42 patients (90.5%) returned to competition after conservative treatment. The mean time to return was 13.8 ± 7.6 weeks, and the mean conscious performance score was 58.4 ± 16.5%. Thirty-eight patients (90.5%) experienced their knee giving way, of whom 36 (94.9%) stated that fear of their knee giving way hampered their performance. At the time of ACL reconstruction, 9 patients had chondral injuries and 22 patients had meniscus injuries. CONCLUSION: Most athletes with damaged ACLs returned to the field within the same season after conservative treatment. However, conscious performance was only about 60%. It is possible that knees giving way caused secondary meniscus and joint cartilage damage. Therefore, conservative treatment of individuals with ACL injuries should be considered carefully.

Technique of anatomical single bundle ACL reconstruction with rounded rectangle femoral dilator.

BACKGROUND: This study aimed to present a new technique for anatomical single bundle anterior cruciate ligament (ACL) reconstruction. We developed an original rounded rectangular dilator set to create rounded rectangular femoral tunnels. This technique can increase the femoral tunnel size without roof impingement, and has the potential to reduce the graft failure rate. We investigated the tunnel position and the incidence of intraoperative complications. METHOD: The presented technique is anatomical single bundle ACL reconstruction using a semitendinosus graft (with or without the gracilis tendon). The tunnel was drilled via an additional medial portal. Rounded rectangular tunnels were created using a special dilator. Tibial tunnels were created using conventional rounded tunnels. Fixation was achieved using a suspensory device on the femoral side and a plate and screw on the tibial side. PATIENTS: Fifty patients underwent this surgery, and intraoperative complications were investigated. The femoral tunnel positions were documented postoperatively from computed tomography scans using the quadrant method. The tibial tunnel positions (anterior-to-posterior, medial-to-lateral) were documented using intraoperative X-ray scans. RESULTS: Only one patient had a partial posterior tunnel wall blowout. The femoral tunnel length varied between 30 and 40mm (mean, 34.9±3.3mm). All femoral and tibial tunnels were located within the area of the anatomical ACL insertions. CONCLUSION: We did not experience any serious intraoperative complications during anatomical single bundle ACL reconstruction using a rounded rectangle dilator, and the resulting locations of the femoral and tibial tunnels were within the anatomical ACL footprint. LEVEL OF EVIDENCE: Level IV.

Grafted tendon healing in femoral and tibial tunnels after anterior cruciate ligament reconstruction.

PURPOSE: To evaluate tendon-to-bone healing after anterior cruciate ligament (ACL) reconstruction in the fibrous interzone (FIZ) of the femoral and tibial tunnels using magnetic resonance imaging (MRI). METHODS: Five men and 5 women (mean age, 29 years) underwent arthroscopic ACL reconstruction by a single surgeon, using the semitendinosus and gracilis tendon. The tendon-to-bone healing in the FIZ was evaluated using sagittal and coronal MRI at 1, 3, 6, 9, 12, and 24 weeks, with the knee flexed at 60º and the tendon graft straight in both images. The signal intensity of the FIZ was visually assessed by comparing it with anatomic landmarks in the same patient's knee, and classified into 4 grades. It was grade 3 when similar to that of the patellar tendon, grade 2 when similar to that of skeletal muscle, grade 1 when greater than that of muscle but less than that of joint fluid, and grade 0 when similar to that of joint fluid. At 24 weeks, subjective and objective functional outcomes were evaluated using the Lysholm score and the International Knee Documentation Committee score. RESULTS: At 24 weeks, no patient had knee laxity. All patients had an International Knee Documentation Committee score of A, and their mean Lysholm score was 98.5. In the femoral tunnel, the FIZ did not change during the first 9 weeks (in particular the anterior part), but healing occurred rapidly thereafter. In the tibial tunnel, the FIZ healed over time in all locations, and healing was complete in the lateral and posterior parts at 12 weeks, and in all locations at 24 weeks. The mean signal intensity grade was significantly higher in the tibial than femoral FIZ at 3 to 12 weeks (p<0.01). CONCLUSION: After ACL reconstruction, the tendon-to- bone healing in the FIZ of the tibial tunnel was faster than that of the femoral tunnel.

Oblique coronal and oblique sagittal MRI for diagnosis of anterior cruciate ligament tears and evaluation of anterior cruciate ligament remnant tissue.

BACKGROUND: The purpose of this study was to investigate the efficacy of additional oblique magnetic resonance imaging (MRI) for the diagnosis of anterior cruciate ligament (ACL) tear and evaluation of ACL remnant tissue. METHODS: We retrospectively reviewed the records of 54 knees. Three independent readers evaluated the MR images by the use of three methods: orthogonal sagittal images only (method A); orthogonal sagittal and additional oblique sagittal images (method B); and orthogonal sagittal and oblique coronal images (method C). The sensitivity, specificity, and accuracy for the diagnosis of an ACL tear and the detection of the condition of the ACL remnant tissue by the use of each method were calculated in comparison with arthroscopic findings as the reference standard. RESULTS: The arthroscopic records revealed 27 knees with intact ACLs and 27 with torn ACLs. Among the 27 knees with torn ACLs, 9 did not have continuous remnant tissue and 18 had certain remnant tissue attached to the femur or the posterior cruciate ligament. The specificities and accuracies of methods B and C for diagnosing an ACL tear were higher than those for method A. The sensitivity, specificity, and accuracy of method C for the detection of ACL remnant tissue were higher than those for method A and B. CONCLUSIONS: Additional use of oblique MRI improved the accuracy of diagnosis of ACL tear and showed a reasonable level of efficacy in detecting ACL remnant tissue. LEVEL OF EVIDENCE: Level IV (case series).

Whole body muscle activity during the FIFA 11+ program evaluated by positron emission tomography.

PURPOSE: This study investigated the effect of the FIFA 11+ warm-up program on whole body muscle activity using positron emission tomography. METHODS: Ten healthy male volunteers were divided into a control group and a group that performed injury prevention exercises (The 11+). The subjects of the control group were placed in a sitting position for 20 min and 37 MBq of (18)F-fluorodeoxyglucose (FDG) was injected intravenously. The subjects then remained seated for 45 min. The subjects of the exercise group performed part 2 of the 11+for 20 min, after which FDG was injected. They then performed part 2 of the 11+for 20 min, and rested for 25 min in a sitting position. Positron emission tomography-computed tomography images were obtained 50 min after FDG injection in each group. Regions of interest were defined within 30 muscles. The standardized uptake value was calculated to examine the FDG uptake of muscle tissue per unit volume. RESULTS: FDG accumulation within the abdominal rectus, gluteus medius and minimus were significantly higher in the exercise group than in the control group (P<0.05). CONCLUSION: The hip abductor muscles and abdominal rectus were active during part 2 of the FIFA 11+ program.