Insufficient restoration of meniscal extrusion by transtibial pullout repair for medial meniscus posterior root tears.

PURPOSE: The long-term changes in the dynamics of the medial meniscus after transtibial pullout repair for medial meniscus posterior root tears (MMPRTs) are not completely understood. Thus, the aim of this study was to investigate the effects of transtibial pullout repair on MMPRTs and whether the effects would be sustained. METHODS: Nineteen knees with MMPRTs that were treated by trans-tibial pullout repair were enrolled in this study. Medial meniscus extrusion (MME) was measured by ultrasonography during knee extension (no weight-bearing with the knee at 0° extension: NW0°) and 90° flexion (no weight-bearing with the knee at 90° flexion: NW90°) with the patient in the supine position and with full weight-bearing (FW0°) preoperatively and at 3 and 12 months postoperatively. The clinical outcomes were assessed using the Knee Injury and Osteoarthritis Outcome Score, Lysholm score, and International Knee Documentation Committee score. RESULTS: The difference in MME with NW0° was not statistically significant between the preoperative (3.4 ± 1.0 mm) and 12-month postoperative (3.7 ± 0.6 mm) time points. The MME with NW90° at 3 (2.1 ± 0.7 mm) and 12 months (2.9 ± 0.6 mm) postoperatively were significantly lower than the preoperative values (3.4 ± 0.8 mm) (P < 0.05). However, the value significantly increased from 3 to 12 months postoperatively (P < 0.05). The MME with FW0° at 12 months postoperatively (4.3 ± 0.6 mm) was significantly larger than that at pre-operatively (3.6 ± 0.9 mm) (P < 0.05). All the patients' clinical conditions were significantly improved at 12 months postoperatively when compared to their preoperative clinical conditions. CONCLUSION: Surgery did not reduce the extrusion in the no weight-bearing and weight-bearing positions at knee extension, and these values increased in the postoperative period. In addition, while the surgery reduced the extrusion in the knee flexion position, the restoration achieved by the surgery was not sustained in the long term. LEVEL OF EVIDENCE: Level IV.

Hallux valgus deformity and postural sway: a cross-sectional study.

BACKGROUND: Hallux valgus deformity has been reported to be associated with increased postural sway. However, the direction and magnitude of postural sway associated with hallux valgus remain inconclusive. We assessed the association between hallux valgus deformity and postural sway using a force plate. METHODS: The subjects were 169 healthy volunteers, > 40 years old (63 males, 106 females, average age: 66.0 ± 12.4 years old), who took part in an annual medical examination. We investigated the photographic hallux valgus angle (°), total trajectory length of the gravity center fluctuation (mm), area of the center of pressure (mm2), mediolateral and anteroposterior postural sway (mm) in a standing position with 2-legged stance and eyes open, hallux pain (Numerical Rating Scale), trunk and lower limb muscle mass (kg). We classified the subjects into a hallux valgus group (n = 44, photographic hallux valgus angle of 1 or both feet ≥ 20°) and a no hallux valgus group (n = 125, photographic hallux valgus angle of both feet < 20°) and analyzed the relationship between hallux valgus and postural sway. RESULTS: The anteroposterior postural sway in the hallux valgus group (6.5 ± 2.8) was significantly greater than in the no hallux valgus group (5.4 ± 2.2, p = 0.014), and the lower limb muscle mass in the hallux valgus group (12.4 ± 2.2) was significantly smaller than in the no hallux valgus group (13.5 ± 3.2, p = 0.016). The total value of the photographic hallux valgus angle on both feet was positively correlated with the anteroposterior postural sway (p = 0.021) and negatively correlated with the lower limb muscle mass (p = 0.038). The presence of hallux valgus (p = 0.024) and photographic hallux valgus angle (p = 0.008) were independently related to the magnitude of anteroposterior postural sway. CONCLUSIONS: Hallux valgus deformity and its severity were positively associated with the magnitude of the anteroposterior postural sway. TRIAL REGISTRATION: 2017 - 135. Registered 22 August 2017.

Sagittal Inclination Angle of Graft Is Associated With Knee Stability After Anatomic Anterior Cruciate Ligament Reconstruction.

PURPOSE: To evaluate whether the sagittal inclination angle (SIA) of a graft is associated with postoperative knee stability after anatomic anterior cruciate ligament (ACL) reconstruction. METHODS: All patients who had undergone anatomic ACL reconstruction between April 2014 and September 2015 in addition to volunteers with no history of knee injury were eligible for inclusion in this study. The patients were evaluated by magnetic resonance imaging of the knee in full extension at 1 year after surgery, as were volunteers. The posterior tibial slope (PTS) angle and the SIA of the intact ACL and reconstructed graft were measured relative to each medial and lateral tibial plateau. The patients were examined for knee stability by the side-to-side difference in the anterior tibial translation on stress radiographs at minimum 2-year follow-up. RESULTS: We included 43 patients (26 male, 17 female, mean age 32.8 ± 14.8 years) and 12 volunteers (7 male, 5 female, mean age 28.7 ± 3.1 years) as normal controls. The mean follow-up duration was 29.8 ± 3.6 months. The mean PTS angle and mean SIA in the patients did not significantly differ from those of the intact ACL. The PTS angle in the patients was not significantly correlated with postoperative side-to-side difference in the anterior tibial translation. However, the graft SIA was significantly correlated with the postoperative anterior tibial translation (medial SIA; r = 0.42, P = .005, lateral SIA; r = 0.52, P < .001). CONCLUSIONS: Even if anatomically reconstructed, the graft SIA in reference to the tibial plateau at full knee extension is variable and is associated with postoperative knee stability. The larger graft SIA was correlated with graft laxity after anatomic ACL reconstruction. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Patient-reported evaluation on giving way is important for return to preinjury activity level after Anterior Cruciate Ligament reconstruction.

PURPOSE: The present study evaluated the rate of returning to the preinjury level of competitive sports after ACLR and influential factors. METHODS: After excluding composite ligament injury cases, 96 patients with a Tegner activity score of ≥ 6 who were managed between April 2015 and March 2016 and had been followed for ≥ 2 years were included in the present study. The patients were evaluated for instability, and the following data were collected: second-look arthroscopy findings, muscle strength, and International Knee Documentation Committee (IKDC) subjective score (follow-up rate: 88.1%). RESULTS: The rate of returning to the preinjury level of competitive sports was 62/96 (64.6%). Only the total IKDC subjective score (odds ratio, 1.052; 95% confidence interval 1.004-1.102; p = 0.035) and the subjectively evaluated item about giving way (odds ratio, 1.762; 95% confidence interval 1.066-2.911; p = 0.027) were independently associated with the returning to the preinjury level of competitive sports after ACLR in the logistic regression analysis. CONCLUSION: The rate of returning to the preinjury level of competitive sports after ACLR was 64.6%, even if a good knee stability and healing status of the sutured meniscus were acquired after ACLR. The IKDC subjective score, especially the item about giving way, was significantly associated with the returning to the preinjury level of competitive sports. The factors assessed by patient-reported evaluations concerning giving way that may be related to functional performance, including brain activity, are important to consider to improve the rate of returning to the preinjury level of competitive sports. LEVEL OF EVIDENCE: III.

Patient age as a preoperative factor associated with tunnel enlargement following double-bundle anterior cruciate ligament reconstruction using hamstring tendon autografts.

PURPOSE: A few studies have detected associations of post-operative tunnel enlargement with sex, age, and the timing of anterior cruciate ligament reconstruction (ACLR). The aim of the present study was to investigate the correlation between post-operative tunnel enlargement following ACLR using hamstring tendon autografts and preoperative factors. The authors hypothesized that tunnel enlargement is associated with age in patients undergoing ACLR. METHODS: One hundred and six patients (male, n = 57; female, n = 49; mean age, 26.9 years) who underwent double-bundle ACL reconstruction were included in the present study. The time between injury and surgery was 26.3 ± 71.4 weeks. Computed tomographic scans of the operated knee were obtained at 2 weeks and 6 months after surgery. The area of the tunnel aperture was measured for the femoral anteromedial tunnel (FAMT), femoral posterolateral tunnel (FPLT), tibial anteromedial tunnel (TAMT), and tibial posterolateral tunnel. The percentage of tunnel area enlargement was defined as the area at 2 weeks after ACLR subtracted from the area at 6 months after ACLR and then divided by the area at 2 weeks after ACLR. Spearman's correlation coefficient was calculated for each factor. The patients were divided into two groups based on age. Patients aged <40 and ≥40 years were assigned to Groups A and B, respectively. The differences in the outcomes and characteristics of the two groups were evaluated. RESULTS: The percentage of enlargement of the FAMT, FPLT, and TAMT was correlated with patient age (r = 0.31, p = 0.001; r = 0.24, p = 0.012; and r = 0.30, p = 0.002, respectively). In total, 87 and 19 knees were classified into Groups A and B, respectively, based on patient age. The percentage of enlargement of the FAMT was significantly higher in Group B than A (78 vs. 60%, respectively; p = 0.01). The percentage of enlargement of the TAMT was significantly higher in Group B than A (53 vs. 36%, respectively; p = 0.03). CONCLUSION: The percentage of enlargement of the FAMT and TAMT was associated with patient age. These findings suggest the need to consider the possibility of tunnel enlargement when double-bundle ACLR is performed for patients aged >40 years. Age was a preoperative factor associated with tunnel enlargement. LEVEL OF EVIDENCE: III.

The remnant preservation technique reduces the amount of bone tunnel enlargement following anterior cruciate ligament reconstruction.

PURPOSE: The aim of the present study was to investigate the correlation between postoperative tunnel enlargement after ACLR and remnant tissue preservation using the hamstring tendon. METHODS: One hundred and ninety-two subjects (male, n = 101; female, n = 91; mean age 27.1) who had undergone double-bundle ACL reconstruction were included in the present study. The patients were divided into two groups: the remnant tissue preservation group (Group R) and the non-remnant tissue preservation group (Group N). Computed tomographic scans of the operated knee were obtained at 2 weeks and 6 months after surgery. The area of the tunnel aperture for the anteromedial femoral tunnel (FAMT), posterolateral femoral tunnel (FPLT), anteromedial tibial tunnel (TAMT), and posterolateral tibial tunnel (TPLT) was measured. The area at 2 weeks after ACLR was subtracted from the area at 6 months after ACLR and then divided by the area at 2 weeks after ACLR. The differences in the outcomes and characteristics of the two groups were evaluated. RESULTS: Seventy-seven knees were classified into Group R, and 115 knees were classified into Group N. The age, gender, and body mass index did not differ to a statistically significant extent. The percentages of FAMT and TAMT enlargement in Group R were significantly smaller in comparison with Group N (P = 0.003 and P = 0.03, respectively). The percentage of FPLT and TPLT enlargement in the two groups did not differ to a statistically significant extent. CONCLUSION: The remnant-preserving technique reduces the amount of bone tunnel enlargement. The present findings indicate the advantages of the remnant-preserving ACLR technique, and therefore the remnant-preserving technique should be recommended. LEVEL OF EVIDENCE: II.

Evaluation of muscle activity just after straight leg raising exercise by using 18FDG-PET.

BACKGROUND: Exercise therapy is one of the recognized treatment methods for knee osteoarthritis (KOA). One such exercise technique, straight leg raising (SLR), is widely known as a home exercise method for strengthening the quadriceps femoris muscle. However, whether this exercise truly strengthens the quadriceps is not known. The objective of the present study was to investigate which lower limb muscle is stimulated and shows increased activity with SLR. METHODS: A total of 14 lower limbs in seven healthy adult male volunteers (mean age: 31.3 ± 2.2 years) were investigated. Participants were asked to perform SLR and subsequently underwent FDG-PET/CT examination for evaluation of the muscles of the entire lower limb. The maximum standardized uptake value (SUVmax) of each muscle (iliacus, psoas major, gluteus maximus, gluteus medius, gluteus minimus, vastus medialis, vastus intermedius, vastus lateralis, rectus femoris, biceps femoris, semimembranosus, semitendinosus, adductor, sartorius, gracilis, tibialis anterior, tibialis posterior, soleus, medial head of gastrocnemius, and lateral head of gastrocnemius) was measured in four cross-sections: at the trunk, pelvis, thigh, and lower leg. RESULTS: SUVmax was significantly greater in: iliacus and adductor compared to vastus medialis, vastus lateralis, biceps, semitendinosus, gracilis, tibialis anterior, and gastrocnemius; psoas major compared to all muscles except for gluteus minimus and adductor; gluteus minimus compared to all muscles except for iliacus, psoas major, gluteus medius, and adductor; and gluteus medius compared to semitendinosus and gracilis. CONCLUSIONS: After SLR, SUVmax was significantly greater in iliacus, psoas major, gluteus minimus, gluteus medius, and adductor compared to some of the other muscles. Performing SLR increased glucose metabolism of the above muscles in particular, and this may have increased their activity levels.

Relation between the stand-up test and gait speed, knee osteoarthritis, and osteoporosis using calcaneal quantitative ultrasound - Cross-sectional study.

OBJECTIVE: The aim of the present study was to clarify the relationship between the stand-up test and gait speed, knee osteoarthritis (OA), and osteoporosis using calcaneal quantitative ultrasound. STUDY DESIGN: Cross-sectional study. METHODS: A total of 185 subjects (55 men, 130 women) aged ≥40 years (mean age, 63.7 years; range, 40-79 years) were evaluated using the stand-up test to screen for locomotive syndrome. We also assessed OA of the knee using X-rays and a subjective questionnaire, physical characteristics, 6-m gait speed (m/s), and bone density. If results on the stand-up test were worse than benchmarks by age group (i.e., the height at which 50% of each age group could stand-up), the subject was defined as having a risk for locomotive syndrome (L group). We analyzed the relationship between the stand-up test and other variables. RESULTS: Of 185 subjects, 50 (27.0%) were classified into the L group. In univariate analysis, there were significant differences between the L group and non-L group in bone density (p < 0.001), gait speed (p < 0.001), osteoporosis (p < 0.001), slow gait speed group (SGSG) (cut off 1 m/s), and Japanese knee osteoarthritis measure score. Multivariate logistic regression analysis adjusted for age, height, weight, and gender showed a significant association between the stand-up test and bone density (OR 0.960, 95% confidence interval (95% CI) 0.927-0.994), gait speed (m/s) (OR 0.073, 95% CI 0.016-0.342), osteoporosis (OR 3.710, 95% CI 1.410-9.764), and SGSG (OR 7.849, 95% CI 1.628-37.845). CONCLUSIONS: The stand-up test to screen for the risk for locomotive syndrome was associated with bone density, gait speed, osteoporosis, SGSG. The stand-up test is an easy test to use to screen for possible disability among the elderly.

Relationship between knee osteoarthritis and the locomotive syndrome risk tests: A cross-sectional study.

OBJECTIVE: To determine the relationship between locomotive syndrome (LS) risk tests and knee osteoarthritis (KOA). STUDY DESIGN: Cross-sectional cohort study. METHODS: In 2015, 225 people (male 84, females 141, mean age 67.9, range 30-90) were examined using LS risk tests, including the stand-up test, the two-step test, and the 25-question risk assessment, in Katashina Village in Gunma prefecture. The Japanese orthopaedic association defined LS risk test stage 1, difficulty with standing from a 40-cm-high seat using one-leg in the stand-up test, two-step test <1.3, the 25-question risk assessment ≧7, and defined stage 2, difficulty with standing from a 20-cm-high seat using both legs in the stand-up test, two-step test <1.1, the 25-question risk assessment ≧16. Persons with two or more of the following on the ultrasound (US) assessment were defined as having KOA: peripheral joint space (PJS) < 5 mm during weight-bearing; medial radial displacement (MRD) > 5 mm during weight-bearing; and osteophytes > 2 mm. If the residents had KOA in either knee, they were defined as having KOA. RESULTS: 45 residents had KOA in either knee. Logistic regression analysis adjusted for age, height, weight, gender, and knee pain was performed with stage 0 as reference. On the stand-up test, the odds ratio was 5.484 (95% confidence interval (CI) 1.966-15.297) for stage 1 and 2.067 (95% CI 0.426-10.017) for stage 2. On the two-step test, the odds ratio was 1.497 (95% CI 0.557-4.021) for stage 1 and 0.71 (95% CI 0.210-2.395) for stage 2. On the 25-question risk assessment, the odds ratio was 1.73 (95% CI 0.646-4.631) for stage 1 and 1.5 (95% CI 0.508-4.433) for stage 2. CONCLUSIONS: A stand-up test of stage 1 had a significant relationship with KOA. This might suggest that proper care of KOA is needed to prevent progressive disability.

Association between neck and shoulder pain, back pain, low back pain and body composition parameters among the Japanese general population.

BACKGROUND: Neck and shoulder pain, back pain and low back pain are common symptoms in Japanese subjects, and it is important to elucidate the pathology and associated factors of these pains due to their frequency and impact on the quality of life (QOL) and activities of daily living (ADL). The purpose of the present study was to investigate whether body composition is associated with these pains. METHODS: We collected the data of 273 Japanese subjects regarding the presence and the visual analogue scale (VAS) of neck and shoulder pain, back pain, low back pain and body composition parameters calculated using bioelectrical impedance analysis (BIA) technology. Furthermore, we investigated the association between these pains and the body composition using statistical methods. RESULTS: According to a multivariate analysis adjusted for age and gender, lower total body water ratio was significantly associated with the presence of neck and shoulder pain at present (P < 0.05); additionally, total body muscle mass (standardized ß = -0.26, 95 % CI, -0.17 - -0.008, P < 0.05), total body water (standardized ß = -0.27, 95 % CI, -0.23 - -0.04, P < 0.01), appendicular muscle mass (standardized ß = -0.29, 95 % CI, -0.36 - -0.04, P < 0.05), and the appendicular muscle mass index (AMI) (standardized ß = -0.24, 95 % CI, -1.18 - -0.20, P <0.01) were negatively correlated with the VAS of neck and shoulder pain, whereas no body composition parameters were significantly associated with back pain, low back pain at present and any type of chronic pain. CONCLUSIONS: The present study demonstrated that some body composition parameters regarding body water and body muscle were associated or correlated with the presence or intensity of neck and shoulder pain.

Sonographic evaluation of the medial aspect of the knee in a population-based cohort study.

PURPOSE: The aim of this study was to evaluate the medial aspect of the knee with ultrasound (US). METHODS: This study included 71 men and 154 women (450 knees) with a mean age of 65 years. US was used to evaluate the medial joint space of both knees with and without weight-bearing. In each subject, the medial radial displacement of the medial meniscus, the peripheral joint space, and the number of osteophytes were evaluated. The subjects were stratified by age into five groups: 40-49 years, 50-59 years, 60-69 years, 70-79 years, and 80 years and older, and the US findings in each group were compared. RESULTS: Statistically significant differences were noted between the 60-69 and over-80 age groups in medial radial displacements and peripheral joint spaces (p < 0.01 for both). The number of osteophytes significantly increased after 60 years of age (p < 0.01). CONCLUSIONS: We believe that US is a useful tool for making a simple evaluation of the intra-articular components in population-based studies.

Influence of the anterior-posterior femoral translation on the range of motion in cruciate-retaining total knee arthroplasty.

PURPOSE: The purpose of this study is to evaluate the post-operative range of motion (ROM) of the knee related to the anterior-posterior femoral translation on the tibia observed during surgery in cruciate-retaining total knee arthroplasty (TKA) using a navigation system. Our hypothesis is that the intraoperative anterior-posterior femoral translation is correlated with the post-operative ROM in patients undergoing cruciate-retaining TKA. METHODS: The subjects were 20 patients involving 23 joints. The passive maximum ROM was measured before and 1 year after surgery. In addition, we evaluated the intraoperative anterior-posterior femoral translation that was measured after inserting a tensor device from 10° to 120° of knee flexion. The starting point of the anterior-posterior femoral translation was defined as when the femur started to move posteriorly. The anterior-posterior femoral translation 120 was set as the amount of femoral movement from 10° to 120°. RESULTS: The subjects were divided into those with an increased or maintained ROM (group A) and those with a decreased ROM (group B). There were no significant differences between the two groups in terms of the age or pre-operative ROM. The starting point of the anterior-posterior femoral translation was significantly earlier in group B (58.0 ± 5.7° for group A, 48.7 ± 3.2° for group B) (P < 0.05). Regarding the anterior-posterior femoral translation 120, Group B showed a larger amount of femoral movement posteriorly than group A (13.0 ± 6.5 mm for group A, 19.0 ± 6.2 mm for group B) (P < 0.05). CONCLUSIONS: The present study shows that intraoperative anterior-posterior femoral translation has a significant correlation with the post-operative ROM in patients undergoing cruciate-retaining TKA. If the starting point of the anterior-posterior femoral translation is early and the anterior-posterior femoral translation 120 is large, there is likely to be a decrease in the post-operative ROM. LEVEL OF EVIDENCE: III.

Morphological evaluation and diagnosis of medial type osteoarthritis of the knee using ultrasound.

OBJECTIVE: The aim of this study was to diagnose osteoarthritis (OA) of the knee joint using ultrasound (US). METHODS: The study subjects included 27 males and 54 females (131 knees), who had a mean age of 62.8 years. US was used to evaluate the medial joint space of both knees in complete extension with and without weight-bearing. In each patient, the medial radial displacement of the medial meniscus (MRD), the peripheral joint space (PJS) and the number of osteophytes were evaluated. The subjects were divided into five groups based on the KL grade (0-4), and then each value was compared. Additionally, the subjects were divided into two groups: KL grade 0 and 1 (non-OA group) and KL grade 2-4 (OA group). We classified patients who met the following criteria as having OA on the US assessment: <5 mm of PJS during weight-bearing, >5 mm of MRD during weight-bearing, and >2 mm of osteophytes. Then we examined the diagnostic accuracy of the radiographic diagnosis (non-OA or OA of the knee) using US assessment. RESULTS: The PJS was significantly decreased and the MRD was significantly increased in the OA group compared to the non-OA group (p < 0.001). The percentage of radiographic OA of the knee that was correctly diagnosed by ultrasound was 90.8 % (sensitivity), with a specificity of 95.5 %. The positive predictive value was 97.5 % and the negative predictive value was 84.0 %. CONCLUSIONS: Our study therefore showed that US has both a high reliability and excellent diagnostic accuracy.

Population-based study of the relationship between medial meniscus radial displacement, determined by use of ultrasound screening, and knee pain.

PURPOSE: The purpose of this population-based study was to clarify the incidence of knee pain by use of ultrasound (US). METHODS: Medical check-ups were conducted for residents of a mountain village in Japan. The subjects were 149 males and 252 females (802 knees) with a mean age of 63.5 ± 12.5 years. US was used to evaluate the medial joint space of both knees, with and without weight-bearing. For each patient, medial radial displacement of the medial meniscus (MRD) and number of osteophytes were evaluated. A questionnaire was used to determine whether the subjects were currently experiencing knee pain while walking, climbing stairs, or resting that had lasted more than one month. A visual analog scale was used to assess knee pain. The subjects were divided into two groups, those with knee pain (P group) and those without knee pain (non-P group), on the basis of whether a visual analog scale (VAS) was less than or more than 20 mm during walking, climbing stairs, or resting. Logistic regression analysis was used to identify the factors associated with knee pain. RESULTS: Significantly different weight-bearing MRD (WMRD), osteophytes, and pain while walking, climbing stairs, or resting (p < 0.01) were found between the two groups. Logistic regression analysis showed that WMRD was significantly associated with knee pain during walking or while climbing stairs. CONCLUSION: We found that WMRD was significantly associated with knee pain while walking or climbing stairs, which are weight-bearing activities. On the basis of the findings of this study, we believe US is a useful tool for evaluating the factors associated with knee pain in a population-based study. LEVEL OF EVIDENCE: Level III.

The Usefulness of Posterior Shiny Corner Lesions in the Early Diagnosis of Medial Meniscus Posterior Root Tears.

INTRODUCTION:  Posterior shiny corner lesions (PSCLs) have been reported to be useful for the early diagnosis of medial meniscus posterior root tears (MMPRTs) in surgical patients. However, the usefulness of PSCLs in outpatients, particularly regarding the optimal timing of magnetic resonance imaging (MRI) examinations after injury, remains unknown. We hypothesized that PSCLs would normally be observed in patients with MMPRTs within one month of injury. MATERIALS AND METHODS:  This study included 144 patients with knee pain who visited our hospital between January 2021 and May 2023. MRI findings within and after one month were examined. Fisher's exact test was performed for PSCLs, cleft signs, ghost signs, radial tear signs, bone cysts, and medial meniscus extrusion (MME), which are findings used for the diagnosis of MMPRTs. Time-dependent receiver operating characteristic (ROC) curve analysis was performed for each MRI finding. A binomial logistic regression analysis was performed for age, sex, PSCL, ghost sign, and MME. RESULTS: PSCLs were observed on 82.6% of the MRI scans within one month, but the positivity rate decreased after one month. After one month, a high percentage of patients had cleft signs and ghost signs. The results of a time-dependent ROC curve analysis showed that the PSCL had better diagnostic ability than the cleft sign, ghost sign, radial tear sign, and MME at a relatively early stage. Additionally, the area under the curve (AUC) of PSCL peaks around 35 days and then declines, reaching 0.8 or less around 40 days. On the other hand, the AUC of the cleft sign and ghost sign began to increase around 30 days after injury, and it exceeded 0.8 after approximately 100 days. The results of the binomial logistic regression analysis revealed significant PSCLs and ghost signs. Independent associations between the PSCL, or ghost sign, and the MMPRT were demonstrated. CONCLUSION:  This study suggests that PSCLs have a superior diagnostic capability for MMPRT during the early stages of injury compared with other MRI findings in outpatients. In particular, PSCLs have a high positivity rate within one month after injury and a high diagnostic capacity up to 40 days after injury.

Protective Effects of Extracorporeal Shockwave Therapy on the Degenerated Meniscus in a Rat Model.

BACKGROUND: Loss of meniscal function in association with degenerative changes affects the development and progression of knee osteoarthritis, for which there is currently no effective treatment. Extracorporeal shockwave therapy (ESWT) is an established treatment for musculoskeletal disorders. However, the therapeutic effect of ESWT on meniscal degeneration remains unclear. PURPOSE: To evaluate the therapeutic effect of ESWT on the degenerated meniscus in an anterior cruciate ligament transection (ACLT) model. STUDY DESIGN: Controlled laboratory study. METHODS: Twelve-week-old male Wistar rats were randomly assigned to 3 groups (normal, ESWT-, and ESWT+). Unilateral ACLT of the right knee was performed in the latter 2 groups. At 4 weeks after ACLT, the ESWT+ group received 800 shockwave impulses at an energy flux density of 0.22 mJ/mm2 in a single session. Histological changes were examined in the posterior portion of the medial meniscus after ESWT (n = 15 per group). Real-time polymerase chain reaction (PCR) was performed after ESWT (n = 5 per group) to analyze the expression of connective tissue growth factor/CCN family member 2 (CTGF/CCN2), sex determining region Y-box 9, vascular endothelial growth factor α, aggrecan, collagen type 1 alpha 2, and collagen type 2 alpha 1 (Col2α1). Immunohistochemistry was used to analyze the expression of CTGF/CCN2 and Ki-67 (n = 5 per group) after ESWT. RESULTS: The meniscal histopathological score at 4 weeks after ACLT was significantly higher than that in the normal group, and the score in the ESWT+ group was significantly lower than that in the ESWT- group at 4 and 12 weeks after ESWT. Real-time PCR revealed that the mRNA expression of CTGF/CCN2 and Col2α1 decreased 4 weeks after ACLT. In the ESWT+ group, real-time PCR revealed that the mRNA expression of CTGF/CCN2 increased 24 hours after ESWT, and the expression of Col2α1 increased 4 weeks after ESWT (all significant data were P < .05). The ratio of CTGF/CCN2-positive cells and Ki67-positive cells was significantly higher in the ESWT+ group after ESWT. CONCLUSION: The present study revealed that ESWT might suppress ACLT-induced meniscal degeneration by stimulating cartilage repair factors and inducing collagen type 2. CLINICAL RELEVANCE: ESWT can be an effective treatment to protect the degenerated meniscus in a rat model of ACLT.

Postoperative Medial Tilting of the Joint Line and Preoperative Kinematics Influence Postoperative Medial Pivot Pattern Reproduction in Total Knee Arthroplasty.

Background: Reproducing the medial pivot pattern after total knee arthroplasty (TKA) is known to improve patient satisfaction. However, the factors affecting the postoperative medial pivot pattern in TKA are controversial. The purpose of this study was to examine the factors affecting the postoperative medial pivot pattern in posterior-stabilized TKA. Methods: This study involved 30 cases with knee osteoarthritis who underwent primary posterior-stabilized TKA. The preoperative and postoperative kinematics were measured using a computed tomography-free navigation system, and the patients were divided into the following 2 groups: the medial pivot pattern (MP) group and non-medial pivot pattern (non-MP) group. In addition, we measured each of the following angles on X-ray films (preoperative and postoperative femorotibial angle, hip-knee-ankle angle, mechanical lateral distal femoral angle, medial proximal tibial angle). We examine the factors affecting the postoperative medial pivot pattern. Results: There were 14 cases in the MP group and 16 cases in the non-MP group at the preoperative knee kinematic assessment and 17 cases in the MP group and 13 cases in the non-MP group at the postoperative knee kinematic assessment. The preoperative kinematic pattern was conserved after the surgery at a rate of 76.7%. The postoperative MP-group showed a significantly smaller preoperative femorotibial angle and hip-knee-ankle and a significantly smaller postoperative mechanical lateral distal femoral angle and medial proximal tibial angle in comparison to the postoperative non-MP group. Conclusions: Preoperative kinematics and postoperative mechanical lateral distal femoral angle and medial proximal tibial angle may be important factors that affect the postoperative medial pivot pattern.

Arthroscopic evaluation of preserved ligament remnant after selective anteromedial or posterolateral bundle anterior cruciate ligament reconstruction.

PURPOSE: The purpose of this study was to evaluate the clinical results and morphology of the preserved bundle remnants by second-look arthroscopy postoperatively 1 year after selective anteromedial (AM) or posterolateral (PL) bundle ACL reconstruction. METHODS: Between July 2004 and September 2009, 1,000 patients underwent arthroscopic anterior cruciate ligament (ACL) reconstruction at our hospital. Among them, 20 (2%) underwent selective AM bundle (group A) or PL bundle (group P) ACL reconstruction surgery with hamstring tendon autografts. At 1 year after surgery, 19 patients (7 male and 12 female patients; age range, 15 to 57 years) underwent second-look arthroscopic evaluations. The follow-up mean was 40.2 months (range, 24 to 70 months). We evaluated the results of manual knee laxity, anterior knee laxity measured by a Telos device (Telos, Marburg, Germany) at 130 N, Lysholm scores, and International Knee Documentation Committee evaluation form and performed evaluations of morphology by second-look arthroscopy. RESULTS: The side-to-side difference in anterior translation by use of the Telos device at 130 N was improved to 2 ± 2 mm (postoperatively) from 6 ± 2.3 mm (preoperatively) in group A and to 1.02 ± 1.26 mm from 4.93 ± 1.73 mm in group P. By second-look arthroscopy, the graft and preserved remnant of each case was considered to have acceptable synovial coverage and to be taut. CONCLUSIONS: The preserved ACL remnants possess acceptable morphology and the functions of anterior-posterior and rotational stability after surgery. Our procedure can be recommended for surgery on partial ACL tears. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Deep Infrapatellar Bursitis in Preadolescent Baseball Players: A Cross-Sectional Study.

Background: Deep infrapatellar bursitis (DIB) has been detected in cases of Osgood-Schlatter disease (OSD). However, the clinical implications of DIB in the apophyseal stage, during the period when OSD has not yet developed, remain unclear. Purpose: To investigate the factors related to DIB in the apophyseal stage in preadolescent baseball players. Study Design: Cross-sectional study, Level of evidence, 3. Methods: The study participants were junior baseball players who participated in a medical checkup in 2020. We included knees in the apophyseal stage evaluated using ultrasonography, and classified them into the bursitis and no-bursitis groups using color-enhanced Doppler ultrasonography. We also investigated bone lesions of the tibial tuberosity, determined by fragmentation of the bone and irregularity of the ossification center. Demographic data, practice duration, pressure pain on tuberosity, pain while playing baseball (visual analog scale), heel-buttock distance (HBD), straight-leg raise angle, and range of hip internal and external rotation were evaluated. Group comparisons were performed using the Mann-Whitney U test and Fisher exact test, and a logistic regression analysis was performed. Results: A total of 261 knees (139 male players; age 10.5 ± 1.1 years) were included, 30 in the bursitis group and 231 in the no-bursitis group. Bone lesions were present in 4 knees in the bursitis group and in 32 knees in the no-bursitis group; there was no significant relationship between the presence of bone lesions and bursitis. Compared with the no-bursitis group, the bursitis group had a significantly longer practice duration (12.9 ± 3.3 vs 15.2 ± 3.8 hours/week, respectively; P = .003) and larger HBD (0.5 ± 1.3 vs 1.4 ± 2.4 cm, respectively; P = .003). The logistic regression analysis showed that practice duration (P = .001) and HBD (P = .004) were significantly related to the presence of bursitis. Conclusion: DIB in the apophyseal stage was related to practice duration and thigh muscle tightness. These findings may help predict overload and thigh muscle tightness at a very early stage.

Medial meniscus extrusion as a predictor for a poor prognosis in patients with spontaneous osteonecrosis of the knee.

BACKGROUND: Risk factors for the progression of spontaneous osteonecrosis of the knee (SONK) remain unclear. The purpose of this study was to investigate the association between magnetic resonance imaging (MRI) findings of the meniscus and the prognosis of SONK. METHODS: A total of 78 consecutive patients (female 85%; mean age 75.6 ± 7.2 years old) diagnosed with SONK were included. Of these, 30 patients did not receive surgery within 1 year from the onset of SONK (conservative group), while the remaining 48 patients underwent unicompartmental knee arthroplasty due to worsening of symptoms (UKA group). Using MRI findings obtained within 3 months of the onset, we compared the types of meniscus tear and medial meniscus extrusion between the conservative group and UKA group. We performed a receiver operating characteristics (ROC) analysis to estimate the cut-off value. RESULTS: Patients in the UKA group showed greater medial meniscus extrusion (absolute value, 4.2 mm ± 1.9 vs. 2.8 mm ± 1.2, P = 0.001; relative percentage of extrusion (RPE), 45.7% ± 21.5 vs. 30.7% ± 12.9, P = 0.001) and a higher prevalence of radial tear (P = 0.021) than those in the conservative group. In the multivariate analysis, RPE remained a relevant independent factor (P = 0.035) for future UKA. An ROC analysis found that the cut-off point of RPE was 33% (sensitivity, 81.2%; specificity, 63.3%). CONCLUSION: RPE was a predictor of the prognosis of patients who underwent UKA within 1 year after the onset of SONK. Our results suggest that patients with RPE ≥ 33% are at high risk for progression.