Ultrasonographic diagnosis of medial meniscus posterior root tear in early knee osteoarthritis: a comparative study.

INTRODUCTION: This study aimed to detect medial meniscal posterior root tear (MMPRT) diagnostic methods with high sensitivity and specificity using dynamic ultrasonographic evaluation in patients with early knee osteoarthritis (OA) and demonstrate the usefulness of dynamic ultrasonographic medial meniscal extrusion (MME) evaluation in MMPRT diagnosis using a cutoff value. MATERIALS AND METHODS: Between 2018 and 2020, a total of 120 patients were diagnosed with early knee OA using clinical and radiographic findings. Dynamic ultrasonographic evaluations and magnetic resonance imaging were performed in all patients, and 47 patients who had and 73 patients who did not have MMPRT were classified into the MMPRT and non-MMPRT groups, respectively. Age, sex, femorotibial angle, MME of knee extension and flexion, and MME at weight-bearing were compared between the two groups. Additionally, the sensitivity and specificity of significant ultrasonographic findings were calculated using a receiver operating characteristic (ROC) curve. RESULTS: The MMEs under knee extension-flexion and weight-loading in the MMPRT group were significantly larger than those in the non-MMPRT group. ROC curve analysis for each ultrasonographic evaluation condition to diagnose MMPRT indicated that the sensitivity was 72-88% and the specificity was 66-85% when the cutoff values of MME under knee flexion at 0°, 90°, and weight-loading were set at 2.55 mm, 2.00 mm, and 3.55 mm, respectively. The highest sensitivity (88%) and specificity (85%) were exhibited upon > 2 mm MME at a knee flexion of 90° and were the most useful indicators for MME diagnosis. CONCLUSIONS: Ultrasonographic MME evaluations for MMPRT diagnosis showed relatively high sensitivity and specificity in patients with early knee OA. Dynamic ultrasonographic MME evaluation may lead to appropriate additional examinations, early diagnosis, and intervention for MMPRT in patients with early knee OA.

Extrusion of the medial meniscus under a weight-loading condition in early knee osteoarthritis: an investigation using special upright magnetic resonance imaging.

BACKGROUND: Whether the medial meniscus morphology and movement occur under upright loading conditions in early knee osteoarthritis (OA) or medial meniscus posterior root tear (MMPRT) remains unknown. This study aimed to evaluate the medial and anteroposterior extrusion of the medial meniscus under unloaded and upright-loaded conditions in patients with early knee OA. METHODS: Twelve patients with early knee OA and 18 healthy adult volunteers participated in this study. Magnetic resonance imaging using special equipment was performed with the participants in the unloaded and upright-loaded conditions. Medial, anterior, and posterior extrusions of the medial meniscus against the tibial edge were evaluated and compared between the early knee OA and healthy adult control groups. Additionally, 12 patients in the early knee OA group were divided into 2 subgroups based on whether MMPRT was observed, and the extrusion of the medial meniscus was compared. RESULTS: The amount of medial extrusion of the medial meniscus in both the unloaded and upright-loaded conditions was significantly greater in the early knee OA group than in the control group (unloaded: 2.6 ± 1.0 mm vs 0.7 ± 0.5 mm; upright-loaded: 3.7 ± 0.9 mm vs 1.8 ± 0.8 mm). Similarly, the anterior and posterior extrusion of the medial meniscus in the upright-loaded condition was significantly larger in the early knee OA group (anterior: 4.6 ± 1.0 mm vs 3.7 ± 1.1 mm; posterior: -3.4 ± 1.1 mm vs -4.6 ± 1.6 mm). However, no difference was observed in meniscal extrusion between unloaded and upright-loaded conditions. The posterior extrusion of the medial meniscus in the upright-loaded condition was significantly greater in MMPRT cases than in non-MMPRT cases in the early knee OA group (MMPRT: -2.7 ± 1.1 mm; non-MMPRT -4.1 ± 1.5 mm). CONCLUSIONS: In early knee OA, significantly large meniscal extrusions of the medial meniscus in both unloaded and upright-loaded conditions were found compared with healthy adults. Among patients with early knee OA, those with MMPRT showed a large posterior extrusion of the medial meniscus in the upright-loaded condition compared with those without MMPRT. LEVEL OF EVIDENCE: Level IV.

Non-use of intra-articular drain after anterior cruciate ligament reconstruction does not affect postoperative knee pain and muscle strength on early period.

Introduction: This study aimed to determine the effect of using an intra-articular drain after anterior cruciate ligament (ACL) reconstruction on early postoperative pain, range of motion (ROM), muscle strength, and complications. Materials and methods: Between 2017 and 2020, of the 200 consecutive patients who underwent anatomical single-bundle ACL reconstruction, 128 patients underwent primary ACL reconstruction with hamstring tendons and were evaluated for postoperative pain and muscle strength at 3 months postoperatively. Sixty-eight patients who received intra-articular drain before April 2019 were classified as group D and 60 patients without an intra-articular drain after ACL reconstruction after May 2019 were classified as group N. Patient background, operative time, postoperative pain, number of additional analgesics used, presence of intra-articular hematoma, ROM at 2, 4, and 12 weeks postoperatively, extensor and flexor muscle strength at 12 weeks postoperatively, and perioperative complications were compared between the two groups. Results: The postoperative pain at 4 h after surgery was significantly greater in group D than in group N although no significant difference was found in the pain felt in the immediate postoperative period and at 1 day and 2 days postoperatively and in the number of additional analgesics used. No significant difference in the postoperative ROM and muscle strength was noted between the two groups. Six patients with intra-articular hematomas in group D and four patients in group N needed puncture by 2 weeks postoperatively, and no significant difference was found between the two groups. Conclusion: Postoperative pain was greater at 4 h postoperatively in group D. Furthermore, the intra-articular drain did not affect muscle strength, ROM, and complications on the early postoperative period. The usefulness of intra-articular drain after ACL reconstruction was considered low. Level of Evidence: Level IV.

Regeneration Using Adipose-Derived Stem Cell Sheets in a Rabbit Meniscal Defect Model Improves Tensile Strength and Load Distribution Function of the Meniscus at 12 Weeks.

PURPOSE: The purpose of this study was to evaluate the mechanical properties, such as the tensile strength and load distribution function, of the meniscus tissue regenerated using adipose-derived stem cell (ADSC) sheets in a rabbit meniscal defect model. METHODS: ADSC sheets were prepared from adipose tissue of rabbits. The anterior half of the medial meniscus was removed from both knees. One knee was transplanted with an ADSC sheet; the contralateral knee was closed without transplantation. Mechanical tests were performed at 4 and 12 weeks posttransplantation. In the tensile test, tensile force was applied to the entire medial meniscus, including the normal area (n = 10/group). Compression tests were performed on the entire knee, with soft tissues other than the ligament removed. A pressure-sensitive film was inserted under the medial meniscus and a 40-N load was applied (n = 5/group). RESULTS: In the tensile test, the elastic modulus in ADSC-treated knees was higher at 12 weeks (ADSC: 70.30 ± 18.50 MPa, control: 43.71 ± 7.11 MPa, P = .009). The ultimate tensile strength (UTS) in ADSC-treated knees at 12 weeks was also higher (ADSC: 22.69 ± 5.87 N, control: 15.45 ± 4.08 N, P = .038). In the compression test, the contact area was larger in the ADSC group at 4 weeks (ADSC: 31.60 ± 8.17 mm2, control: 20.33 ± 2.86 mm2, P = .024) and 12 weeks (ADSC: 41.07 ± 6.09 mm2, control: 30.53 ± 5.47 mm2, P = .04). Peak pressure was significantly lower in ADSC-treated knees at 12 weeks (ADSC: 11.91 ± 1.03 MPa, control: 15.53 ± 2.3 MPa, P = .002). CONCLUSIONS: The regenerated meniscus tissue, 12 weeks after transplantation of the ADSC sheets into the meniscal defect area, had high elastic modulus and UTS. In the meniscus-tibia compartment, the contact area was large and the peak pressure was low. CLINICAL RELEVANCE: ADSC sheets promoted regeneration of meniscus. ADSC sheet transplantation for meniscal defects could be an effective regenerative therapy.

Relationship between anatomical injury site of rectus femoris muscle strain and time taken to return to play in Japanese professional soccer players.

PURPOSE: The rectus femoris has three myotendinous or myoaponeurosis junctions and causes three types of muscle strain anatomically. We aimed to investigate the anatomical injury site of the rectus femoris muscle strain in professional soccer players as well as the characteristic findings on magnetic resonance imaging (MRI) and to evaluate its relationship with the time taken to return to play at competition levels. METHODS: Thirteen Japanese professional soccer players who sustained injuries to the rectus femoris were included in this study. The mechanism of injury, anatomical injury site, severity, absence of hematomas, and time taken to return to competition were evaluated. RESULTS: Ten patients were injured while kicking and three while sprinting. The anatomical injury site was the origin aponeurosis in two cases, intramuscular tendon in eight cases, and distal aponeurosis in three cases. The severity was one-degree in three cases and two-degree in 10 cases. Hematomas were observed in five cases. Cases with injuries caused by sprinting, two-degree injuries, or clear hematomas were associated with significantly longer periods of return to play than the other cases. Additionally, patients with distal aponeurosis-type injuries tended to take a long time to return to the competition. CONCLUSIONS: In rectus femoris muscle strain, it is important to evaluate the anatomical injury site, severity, and absence of hematomas on MRI. Not only the injury mechanism, a clear hematoma, and high severity but also distal aponeurosis injuries may be associated with long periods of return to play at competition levels.

Incidence and temporal changes in lumbar degeneration and low back pain in child and adolescent weightlifters: A prospective 5-year cohort study.

This study was conducted to investigate the incidence of lumbar degeneration findings and low back pain (LBP) in children and adolescent weightlifters using magnetic resonance imaging (MRI) and medical questionnaires over a 5-year period. Moreover, we aimed to reveal the temporal changes in the lumbar vertebrae caused by long-term weightlifting training during the growth period. Twelve children and adolescent weightlifters who participated in weightlifting for >2 years (six boys, six girls, 11.4±2.0 years) were enrolled. Participants underwent annual medical questionnaire surveys, including data on practice frequency, competition history, presence of LBP, and lumbar examinations using MRI during the 5-year follow-up. Lumbar disc degeneration was detected in all the participants after 4 years, and lumbar disc herniation findings were detected in 33% of participants after 5 years; one underwent herniotomy during the follow-up period. Lumbar spondylolysis was detected in 58% of patients at 5 years. Although there were three participants who had LBP in the final year, none had LBP that prevented them from returning to weightlifting. This 5-year cohort study of 12 children and adolescent weightlifters detected lumbar degeneration in all participants. High frequency weightlifting training over a long period during the growth period may increase the risk of developing current and future LBP.

Effect of introducing ultrasonography in medical examinations for elbow injuries among young baseball players.

PURPOSE: This study investigated the usefulness of ultrasonography in medical examinations for detecting elbow injuries, especially capitellar osteochondritis dissecans, among young baseball players. METHODS: Players with current or previous elbow joint pain were enrolled. Medical examinations (range of motion, tenderness, and stress tests) were performed with (2012-2016) or without (2007-2011) ultrasonography. Players with abnormal examination results were advised to undergo additional examinations at a local orthopedic clinic. Differences in the rates of capitellar osteochondritis dissecans detection, secondary examination, and elbow injury prevalence were compared between players who did and did not undergo ultrasonography. RESULTS: We identified 1045 baseball players, aged 9-12 years, who required medical examinations for elbow injuries. Medical examinations without ultrasonography were performed in 346 players (group A), and examinations with ultrasonography were performed in 556 players (group B). Capitellar osteochondritis dissecans was present in 0.3% (1/346) of group A players and 3.0% (17/556) of group B players (p = 0.003). The secondary examination consultation rates were 51.2% (62/121) and 66.0% (270/409) in groups A and B, respectively (p = 0.004). CONCLUSION: Ultrasonography performed as a part of a medical examination can help detect elbow injuries, especially capitellar osteochondritis dissecans, in baseball players. Using ultrasonography in conjunction with medical examinations may contribute to a better understanding of elbow injuries in baseball players and improve consultation rates. Thus, ultrasonography is essential for the evaluation of elbow injuries in young baseball players.

Investigating the histological and structural properties of tendon gel as an artificial biomaterial using the film model method in rabbits.

PURPOSE: This study aimed to evaluate the properties of tendon gel by investigating the histological and structural differences among tendon gels under different preservation periods using a rabbit model. METHODS: Forty mature female rabbits were divided into four groups, each containing ten rabbits, on the basis of in-vivo preservation periods of tendon gels (3, 5, 10, and 15 days). We created the Achilles tendon rupture models using the film model method to obtain tendon gels. Tensile stress was applied to the tendon gel to promote maturation. Histological and structural evaluations of the tendon gel were performed before and after applying the tensile force, and the results obtained from the four groups were compared. RESULTS: Although the day-3 and day-5 tendon gels before applying tensile stress were histologically more immature than the day-10 and day-15 gels, type I collagen fibers equivalent to those of normal tendons were observed in all groups after the tensile process. Based on the surface and molecular structural evaluations, the day-3 tendon gels after the tensile process were molecularly cross-linked, and thick collagen fibers similar to those present in normal tendons were observed. Structural maturation observed in the day-3 tendon gels caused by traction was hardly observed in the day-5, -10, and -15 tendon gels. CONCLUSIONS: The day-3 tendon gel had the highest regenerative potential to become a normal tendon by applying a traction force.

Usefulness of ultrasonography for dynamic evaluation of medial meniscus hoop function in early knee osteoarthritis.

This study aimed to evaluate the dynamics of the medial meniscus during knee flexion-extension by ultrasonography and compare them with MRI findings to confirm the usefulness of ultrasonography for evaluating early knee osteoarthritis (KOA). In total, 100 patients were diagnosed with early KOA using clinical and radiographical findings. Dynamic ultrasonographic evaluation and MRI were performed in all patients. Medial meniscal extrusion (MME) and medial meniscal tears were evaluated via ultrasonography and MRI. Abnormal MME was defined as MME > 2 mm on ultrasonography during knee extension. Patients with abnormal MME were divided into two groups: a decrease group (group D) and a non-decrease group (group N). Age, sex, absence or type of meniscus tear, and MME were compared between the two groups. Of the 100 patients, 75 demonstrated MME > 2 mm at knee extension. MME at all assessment positions using ultrasonography and MRI were significantly greater in group N (n = 34) than that in group D (n = 41). Medial meniscus posterior root tears or radial tears were observed in most cases in group N. A lack of decrease in MME from 0° to 90° of flexion on ultrasonography was a characteristic finding in patients with a loss of meniscal hoop function.

Skeletally immature patient showed lower graft maturity than skeletally mature patient after ACL reconstruction with a rounded rectangular femoral tunnel.

To compare the clinical results and ligamentization of anterior cruciate ligament reconstruction (ACLR) between skeletally immature and mature patients. Two-hundred-and-two patients who underwent primary ACLR were evaluated retrospectively. The clinical outcomes were compared between skeletally immature (immature group 1, n = 27) and mature (control group 1, n = 175) groups. Graft ligamentization of the reconstructed anterior cruciate ligament (ACL) using magnetic resonance imaging (MRI) signal intensity at 6 months postoperatively was compared between immature group 2 (n = 16), which included participants from immature group 1, and control group 2 (n = 32), created by recruiting data-matched controls from control group 1. Immature group 1 had significantly higher revision (14.8%) and pivot shift test positive (22.2%) rates than control group 1 (2.9% and 4.0%, respectively) (P = 0.020 and 0.003, respectively). The signal intensity in immature group 2 were significantly higher at the mid-substance and distal site of the reconstructed ACL than those in control group 2 (P = 0.003 and 0.034, respectively). Skeletally immature patients had higher graft revision and residual rotational laxity rates. Reconstructed ACL in skeletally immature patients showed higher signal intensity on MRI at 6 months postoperatively.

Vertebra-Pediculoplasty: A New Approach to Treatment of Split-Type and Delayed-Union Osteoporotic Vertebral Fracture with a Risk of Cement Dislodgement.

BACKGROUND: The clinical outcomes of balloon kyphoplasty (BKP) for split-type osteoporotic vertebral fractures (OVF) are poor. These may be owing to the vertebral body bifurcating anteriorly and posteriorly when a load is applied and the filled cement being unstable. We report the usefulness of BKP combined with pediculoplasty using cannulated screws (vertebra-pediculoplasty) for OVF with a risk of cement dislodgement. METHODS: Between April 2020 and February 2021, this surgery was performed on 10 patients with split-type and delayed-union OVF. The diagnosis was made using imaging findings on preoperative computed tomography or intraoperative images during balloon inflation. Early postoperative ambulatory rehabilitation was performed, and clinical outcomes were evaluated. RESULTS: Early pain relief was obtained in all patients. The stability of the fractured vertebrae was demonstrated using both supine and seated radiographs from the early postoperative period, and good clinical results were obtained. The cement in this surgery was stabilized using a cannulated screw in the vertebral body, anteroposteriorly, and craniocaudally. The cement mass integrated with the cannulated screw was stabilized with the vertebral lamina and pedicle as a stopper. CONCLUSIONS: Vertebra-pediculoplasty could be an effective method for managing OVF with a high risk of cement dislodgement, which has been difficult to treat using conventional BKP.

Skeletal muscle metabolism on whole-body positron emission tomography during pitching.

BACKGROUND: Electromyography (EMG) has been used for evaluating skeletal muscle activity during pitching. However, it is difficult to observe the influence of movement on skeletal muscle activity in deep-lying regions of the trunk and extremities using EMG. An alternative method that may be used is the measurement of glucose metabolism of skeletal muscle using positron emission tomography-computed tomography (PET-CT). This technique is a reliable measure of muscle metabolism, demonstrating a high correlation with the intensity of muscle activity. This study aimed to evaluate whole-body skeletal muscle metabolism during pitching using PET-CT. METHODS: Ten uninjured, skilled, adult pitchers, who were active at college or professional level, threw 40 baseballs at maximal effort before an intravenous injection of 37 MBq of 18F-fluorodeoxyglucose (FDG). Subsequently, additional 40 balls were pitched. PET-CT images were obtained 50 min after FDG injection, and regions of interest were defined within 72 muscles. The standardized uptake value (SUV) of FDG by muscle tissue per unit volume was calculated, and the mean SUV of the pitchers was compared with that of a healthy adult control group who did not exercise before the measurements. Statistical analysis was performed using a t-test, and P < 0.05 was considered statistically significant. RESULTS: Whole-body PET images showed a significant increase in glucose metabolism in the muscle groups of the fingers and toes in both the throwing and non-throwing sides. Additionally, asymmetric increases in glucose metabolism were observed in the muscles of the thigh. CONCLUSIONS: This is the first study to evaluate whole-body muscle metabolism during pitching using PET-CT. Our findings would be useful in determining the training required for pitchers, and can be further applied to other sporting activities that involve throwing.

Clinical study of anatomical ACL reconstruction using a rounded rectangular dilator.

BACKGROUND: The aim of this study was that to compare clinical results between the rounded rectangular femoral tunnel ACL reconstruction (RFTR) and the conventional round femoral tunnel ACL reconstruction using a hamstring tendon. The hypothesis was that ACL reconstruction performed using the rounded rectangular dilator technique was better than that performed using the conventional round femoral tunnel technique in terms of clinical results and bone tunnel enlargement. METHODS: We conducted retrospective study. After exclusions, 40 patients were included in the conventional anatomical single-bundle ACL reconstruction (ASBR) group and 40 patients were included in the RFTR group. The evaluation items were knee stability, Lysholm knee score, IKDC subjective score at 2 years after surgery and bone tunnel enlargement. RESULTS: The RFTR group had a larger femoral tunnel area (average area, 53.1 ± 4.0 mm2 vs. 46.1 ± 7.0 mm2; P < 0.01), better anteroposterior stability, and higher Lysholm scores than the ASBR group (average side-to-side difference for anterior tibial translation, 0.6 ± 0.8 mm vs. 1.6 ± 1.4 mm; P < 0.01; average Lysholm score, 98.5 ± 2.1 vs. 97.5 ± 3.5; P < 0.01). Further, bone tunnel enlargement ratio was significantly lower in the RFTR group (73 ± 38% vs. 107 ± 41%; P < 0.01). CONCLUSIONS: We designed and developed an original rounded rectangular dilator to perform a novel ACL surgery. This technique can create a larger bone tunnel and improve clinical results than the conventional round anatomical single-bundle ACL reconstruction.

Usefulness of lateral femoral cutaneous nerve block in combination with femoral nerve block for anterior cruciate ligament reconstruction: a prospective trial.

INTRODUCTION: The study aimed to compare the combination of femoral nerve block (FNB) with interspace between the popliteal artery and the capsule of posterior knee (IPACK) block (IPACK group) with the combination of FNB with lateral femoral cutaneous nerve (LFCN) block (LFCN group) for postoperative pain control in patients undergoing anterior cruciate ligament (ACL) reconstruction. We hypothesized that the lower pain scores and decreased suppository use would be noted in patients administered a combination of FNB and IPACK block. MATERIALS AND METHODS: A non-randomized prospective controlled clinical trial was conducted. The IPACK and LFCN groups included 40 patients each. The patients received IPACK block and LFCN block alternately. Thirty minutes prior to the surgery and after administration of general anesthesia, patients received an ultrasound-guided FNB and IPACK block or LFCN block. After ACL reconstruction, the visual analog scale pain scores were recorded at 30 min, 4 h, 8 h, 12 h, 24 h, 48 h, and 72 h after the surgery. The administration and use of analgesic suppositories were assessed. These measures were compared among the treatment types at each time-point using the Welch's t-test. RESULTS: Suppository use was significantly less in the LFCN group than in the IPACK group. The pain scores were significantly lower in the LFCN group at 30 min, 4 h, 48 h, and 72 h after the surgery. CONCLUSION: The combination of FNB with LFCN block during ACL reconstruction significantly reduces pain in the early postoperative period compared to a combination of FNB with IPACK block. LEVEL OF EVIDENCE: Prospective control trial, Level II.

Flexibility of infrapatellar fat pad affecting anterior knee pain 6 months after anterior cruciate ligament reconstruction with hamstring autograft.

This study aimed to identify factors affecting anterior knee pain (AKP) after anterior cruciate ligament reconstruction (ACLR) with hamstring tendon autograft using ultrasonography. Forty-two patients were evaluated by ultrasound, 6 months after ACLR. The thickness of the superficial part of the infrapatellar fat pad was measured, as well as the thickness change ratio between the two angles. Color Doppler evaluated the rate of blood flow in the fat pad. AKP was assessed with the Kujala Scale. The correlations between AKP and age, body mass index, the thickness change ratio, and the grade of increased blood flow were examined. Independent variables showing significant correlations with AKP were used for multiple linear regression analysis. There were significant correlations between AKP and age (r = - 0.68), body mass index (r = - 0.37), the thickness change ratio of the fat pad (r = 0.73) and the grade of increased blood flow (r = - 0.42), respectively. Age and the thickness change ratio of the fat pad affected the AKP score (R2 = 0.56). After ACLR, older age and a decrease in the thickness change ratio of the superficial area of the infrapatellar fat pad appear to affect post-operative AKP after 6 months.

Partial resection of the infrapatellar fat pad during anterior cruciate ligament reconstruction has no effect on clinical outcomes including anterior knee pain.

BACKGROUND: Anterior knee pain (AKP) is a major complication that occurs after anterior cruciate ligament reconstruction (ACLR), even when hamstring tendon (HT) grafts are used. Damage to the infrapatellar fat pad (IPFP) during arthroscopy can cause AKP. The purpose of this study was to evaluate the influence of IPFP preservation on clinical outcomes, including AKP, in patients who underwent ACLR with HT autografts using the inside-out technique. METHODS: Forty-two patients who underwent primary ACLR with HT autografts were prospectively assessed for 2 years after surgery. They were randomly selected to undergo treatment with as much intercondylar IPFP preservation as possible or with intercondylar IPFP resection to confirm the ACL origin on the femoral and tibial sides, especially the femoral footprint in deep flexion of the knee joint. The total IPFP volume was calculated using sagittal MR images before and 6 months after surgery. The patients completed a subjective knee score questionnaire and were assessed for patellar tendon tenderness and pain with the half-squat test or single-leg hop test at 6 months and 2 years postoperatively. RESULTS: There were no differences in the patient characteristics, including age, sex, BMI, time from injury to surgery, and meniscus tear. The difference in the total size of the IPFP preserved was significant (P = 0.004). However, there were no significant differences in the subjective knee scores. Moreover, there were no differences in the clinical assessment parameters between the IPFP preservation and resection groups. CONCLUSIONS: The size of the IPFP decreased more in the resection group than in the preservation group at 6 months after surgery. However, partial IPFP resection, which was used to better visualize the origin of the ACL, had no effect on the clinical outcomes, including AKP. LEVEL OF EVIDENCE: Level II.

Autologous Adipose-Derived Stem Cell Sheet Has Meniscus Regeneration-Promoting Effects in a Rabbit Model.

PURPOSE: This study investigated meniscal regeneration-promoting effects of adipose-derived stem cell (ADSC) sheets in a rabbit meniscal defect models. METHODS: ADSCs were extracted from the interscapular fat pad adipose tissue of 42 mature female Japanese white rabbits. Once cells reached confluence at the third passage, the culture medium was supplemented with ascorbic acid. Within a week, the cells in culture formed removable sheets, which were used as ADSC sheets. Cell death (CD) sheets were created by killing ADSCs by freezing to investigate the need for viable ADSCs in ADSC sheets. The anterior half of the medial meniscus from the anterior root to the posterior edge of the medial collateral ligament was removed from both limbs. An autologous ADSC or CD sheet was transplanted to one knee (ADSC sheet or CD sheet group). The contralateral limb was closed without transplantation following meniscal removal (control group). Rabbits were euthanized 4 and 12 weeks after transplantation to harvest the entire medial menisci. The meniscal tissue area, transverse diameter on the inside of the medial collateral ligament, and histologic score were compared between the 3 groups. RESULTS: The area and transverse diameter of regenerated tissues were larger in the ADSC sheet group than in the control group at 4 and 12 weeks. Further, the histologic score in the ADSC sheet group (8) was significantly greater than that in the control group (4.5) at 4 weeks (P = .02) and greater than that in the CD sheet group (9) (ADSC = 12.5, P = .009) and control group (6) (ADSC = 12.5, P = .0003) at 12 weeks. CONCLUSIONS: Transplantation of the ADSC sheet into the meniscal defect increased the volume and improved the histologic score of the regenerated meniscal tissue. ADSC sheets may have meniscal regeneration-promoting effects in a rabbit model with meniscal defects. CLINICAL RELEVANCE: ADSC sheets do not require a scaffold for implantation in the rabbit model, and this evidence suggests that some tissue regeneration occurs at the site of a surgically created meniscal defect.

Intraoperative fluoroscopy shows better agreement and interchangeability in tibial tunnel location during single bundle anterior cruciate ligament reconstruction with postoperative three-dimensional computed tomography compared with an intraoperative image-free navigation system.

BACKGROUND: Fluoroscopy and navigation systems provide an accurate and reproducible method of guiding anatomical tunnel positioning during anterior cruciate ligament reconstruction (ACLR). The aim was to evaluate the differences in tibial tunnel location assessed by both an intraoperative navigation system and fluoroscopy, validated using a one-week postoperative three-dimensional computed tomography (3DCT). METHODS: The tibial tunnel location in a consecutive series of 35 patients who received a single-bundle ACLR was evaluated by intraoperative navigation system, fluoroscopic image and compared with postoperative 3DCT position. The location to the anterior-posterior (AP) and medial-lateral (ML) direction were compared between all three methods. RESULTS: The tibial tunnel locations were 46.7 ± 4.5%, 44.5 ± 1.9%, and 43.6 ± 2.4% in ML direction, and 42.8 ± 7.6%, 37.9 ± 3.8%, and 37.9 ± 3.7% in AP direction using an intraoperative navigation system, fluoroscopic image and postoperative 3DCT, respectively. Significant differences between the navigation system and fluoroscopic image (ML, P = 0.001; AP, P = 0.006), and the navigation system and 3DCT (ML, P = 0.001; AP, P < 0.001) were seen. However, there was no significant difference between fluoroscopy and 3DCT (ML, P = 0.315; AP, P = 0.999). There was a significant lack of agreement for analyses measured using a navigation system and 3DCT. Fluoroscopy and 3DCT demonstrated an acceptable agreement (ML, rpt = -0.21, P = 0.232; AP, rpt = 0.04, P = 0.826). CONCLUSIONS: A tibial tunnel location assessed by intraoperative fluoroscopy shows better agreement and interchangeability with one-week postoperative 3DCT validation during single-bundle ACLR compared with an intraoperative image-free navigation system.

Partial lateral meniscus anterior root injuries during anatomical single-bundle anterior cruciate ligament reconstruction are likely to occur in women with small skeletons.

PURPOSE: This study aimed to investigate the occurrence and characteristics of lateral meniscus anterior root injuries during anatomical single-bundle anterior cruciate ligament (ACL) reconstruction. METHODS: Between 2011 and 2018, 70 women who had ACL injuries without lateral meniscal tears underwent anatomical single-bundle ACL reconstruction. Using computed tomography, the anatomical relationship between the predicted lateral meniscus anterior root insertion and the tibial tunnel was retrospectively assessed, and the patients were divided into partial lateral meniscus anterior root injury and intact groups. The demographic characteristics, the distances between bony landmarks, the tibial tunnel sizes, and lateral meniscal extrusion assessed by magnetic resonance imaging were compared between the two groups. RESULTS: Thirteen of the 70 patients had suspected partial lateral meniscus anterior root injuries. Patient height was significantly shorter in the injury group than in the intact group (157.7 ± 6.4 vs. 161.4 ± 5.4 cm: p = 0.03); the distance from the apex to the bottom of the slope of the medial intercondylar ridge was significantly shorter in the injury group than in the intact group (15.1 ± 1.9 vs. 16.7 ± 1.4 mm: p = 0.001). CONCLUSIONS: Partial lateral meniscus anterior root injury during anatomical single-bundle ACL reconstruction was suspected in 18% of cases. Patient height and the distance between bony landmarks were significantly shorter in the injury group than in the intact group. Surgeons should understand that even a slight deviation of the tibial tunnel position can lead to partial lateral meniscus anterior root injury in patients with small skeletons. LEVEL OF EVIDENCE: IV.

Incidence of injury in young handball players during national competition: A 6-year survey.

BACKGROUND: An updated injury surveillance of young handball players is needed because of the increased risk of injury in recent handball games with increased intensity. This study examined acute injuries in young handball players during games. METHODS: We retrospectively assessed the injuries occurring during 6 national competitions, including 550 games from 2013 to 2018, held in March of each year. All players were 13 or 14 years old. RESULTS: In total, 169 injuries were reported. The number of match injuries per 1000 player hours was 26.5. The injury incidence in boys was higher than that in girls (p = 0.001). No significant differences were found in injury incidence according to the position and date during the tournament (p = 0.108 and 0.483, respectively). Of all injuries, 43.2% were in the lower extremities and 20.7% affected the upper extremities. Most injuries occurred in the head/face (n = 53, 31.4%), followed by the ankle/foot (n = 41, 24.3%), knee (n = 23, 13.6%), and wrist/hand (n = 22, 13%). The most common injury type was sprain (n = 64, 37.9%), followed by contusion (n = 50, 30.0%) and wound (n = 35, 20.7%). In field players, ankle sprain was the most frequent diagnosis, followed by head/face wound and contusion. In contrast, contusion was the main cause of injury in goalkeepers, followed by wound on the head/face. CONCLUSIONS: Preventive measures focussing on sprains in the lower extremity and improved skill in ball-handling technique should be considered to prevent head/face and wrist/hand injuries, especially in boys. STUDY DESIGN: Retrospective cohort study.