Incidence of anterior cruciate ligament injury patterns in Japanese judo players from a nationwide insurance database.

Objective: This study aimed to characterize the age- and sex-specific Anterior cruciate ligament (ACL) injury rates and related injury patterns in judo players in Japan using the nationwide insurance database. Methods: This was a descriptive epidemiological study. We examined a total of 2142 adolescents with anterior cruciate ligament injuries registered in the insurance system of the Japan Sports Council between January 2009 and December 2018. The age- and sex-specific incidences were estimated for the levels of 7th, 8th, and 9th grades of junior high school and 10th, 11th, and 12th grades of high school. The anterior cruciate ligament injury circumstances were classified into three patterns based on the impact to the involved knee: high-impact valgus force, low-impact trunk displacement, or no-impact knee twisting. Results: The incidence of anterior cruciate ligament injury from the 7th to 12th grades were 0.5, 0.9, 0.9, 6.9, 8.6, and 6.1 per 1000 athlete-years in male players and 1.3, 3.8, 3.4, 16.8, 19.5, and 13.6 per 1000 athlete-years in female players. The most prevalent injury pattern was a low-impact contact injury (42.6%) with Osoto-gari, followed by a high-impact contact injury (29.8%). The concomitant medial collateral ligament (MCL) injury rate was 18.1%, which was correlated with a high-impact contact injury (p = 0.005) by multiple regression analysis. Conclusions: The highest incidence of age- and sex-specific anterior cruciate ligament injury was 19.5 per 1000 athlete-years in female high school students in the 11th grade. The most frequent injury pattern was low-impact contact injury with trunk displacement, indicating that trunk stabilization training could help prevent anterior cruciate ligament injury in judo.

Fifth metatarsal strain distribution during cutting motions in soccer.

The objective of this study was to determine the fifth metatarsal strain generation mechanism during cutting motions performed while playing soccer using a finite element foot model. Five collegiate soccer players performed the side-step cutting and the cross-step cutting motions to measure the three-dimensional foot kinematics, ground reaction force, and plantar pressure distribution. In addition, a finite-element model of a foot consisting of bony structures, ligaments, and skin was constructed from computed tomography images. Simulations were conducted to perform the cutting motions, using the measured foot motion and distributed load on the plantar surface as boundary conditions for the model. During the side-step cutting, the maximum principal strain on the fifth metatarsal was correlated to forefoot adduction angle during stepping out. For cross-step cutting, the maximum principal strain was correlated with plantar pressure at the distal end of the fifth metatarsal. Therefore, to prevent a fracture, it is necessary to take measures to reduce the lateral bending deformation of the forefoot while stepping out during side-step cutting and to reduce the plantar pressure on the distal end of the fifth metatarsal during cross-step cutting.

Comparing Accuracy of the Final Height Prediction Models for Elite Football Players and Developing a New Model.

Objective: This study aimed to assess the accuracy of previously developed height prediction models in male Japanese football players and create new height prediction models. Materials: The participants were elite academy male football players. We collected current height, parent's height, calendar age and bone age in 6th grade of primary school and obtained actual final height at 20 to 28 years old. Methods: We compared the accuracy of two conventional models for predicting final height. These used current height, calendar age and either bone age (Model 1) or parental height (Model 2). We then developed a new model to optimize the coefficients of Model 1 (Model 3). The final model added parental height to Model 3 and optimized the coefficients (Model 4). Results: Prediction accuracy was higher for Model 2 (R = 0.52, P < 0.001) than Model 1 (p = 0.33, P < 0.001). The equation of Model 3 was final height = 0.63229313×actual measured height-8.2541327×calendar age-2.3009853×bone age (TW2)+206.627184. The R-square was 0.49 (P < 0.0001). The equation of Model 4 was final height = 0.32156081×actual measured height - 4.6652063×calendar age+0.41903909×father's height+0.34952508×mother's height-0.740469×bone age(TW2)+62.1007751. The R-square was 0.61 (P < 0.0001). Conclusions: In the two previous conventional models, a formula using parental height had better predictive accuracy. We developed a new height prediction model using current height, calendar age, father's and mother's height and bone age.

Lateral Collateral Ligament Repair for Hallux Metatarsophalangeal Joint Instability in a Collegiate Sumo Wrestler: A Case Report.

Although sprains of the hallux metatarsophalangeal (MTP) joint ligaments occur in barefooted martial arts athletes, few studies discuss the surgical treatments for lateral collateral ligament damage. We report herein a case of lateral collateral ligament repair for chronic hallux MTP joint instability. A 21-year-old male collegiate sumo wrestler injured his left hallux by snagging it on a sumo straw bale at 14 years of age. After entering university (4 years after the injury), he could no longer put weight on his foot at the left hallux; his athletic performance deteriorated, and he was referred to our department by his doctor. He had instability in the MTP joint of the left hallux, and magnetic resonance imaging revealed a tear in the attachment of the lateral collateral ligament to the metatarsal bone. Conservative treatment, such as taping, did not improve the symptoms; thus, surgery was performed, which consisted of passing a strong suture attached to the capsular ligament through a burr hole made in the metatarsal bone and fixing it to the burr-hole wall using an anchor. Postoperatively, the patient's joint instability improved, and he returned to competitive wrestling 4 months after surgery. He was able to put weight on his left hallux, and his athletic performance improved. The follow-up period after surgery was 2 years. In competitive sumo wrestling, hallux weakness and joint instability lead to a significant reduction in performance. Thus, ligament repair is an effective treatment for hallux MTP joint instability that cannot be treated by conservative means.

Second Anterior Cruciate Ligament Injuries After Anterior Cruciate Ligament Reconstruction in Professional Sumo Wrestlers: A Case Series.

BACKGROUND: Anterior cruciate ligament (ACL) injury is one of the most common traumatic injuries in professional sumo wrestlers. Further, ipsilateral reinjuries or contralateral ACL injuries after ACL reconstruction can occur in sumo wrestlers. The incidence of ipsilateral reinjury and contralateral ACL injury after ACL reconstruction ranges from 3% to 13% in a healthy athletic population. PURPOSE: To investigate the current status of second ACL injuries after ACL reconstruction in sumo wrestlers. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Between 1988 and 2015, a total of 139 primary ACL reconstructions were performed in professional sumo wrestlers at our hospital. After exclusion of cases of multiple ligament knee reconstruction and patients in whom the contralateral ACL had been injured previously, 110 cases were included in this study. We investigated the number of second injuries, time from primary reconstruction to second injury, treatment method, and change in official sumo ranking after second injuries. The chi-square test, Student t test, and Fisher exact text were used for statistical analysis. RESULTS: Among 110 wrestlers who underwent ACL reconstruction, second injuries after primary ACL reconstruction occurred in 22 cases (20.0%). Among them, 14 cases (12.7%) entailed ipsilateral reinjury, 11 (10.0%) entailed contralateral injury, and 3 involved combined rerupture and contralateral injury. As for surgical treatment, 5 revision ACL reconstructions were performed for ipsilateral reinjury (35.7%), and 7 ACL reconstructions were performed for contralateral injury (63.6%). Surgical treatment was not performed for the remaining cases. Wrestlers who were treated by revision or contralateral ACL reconstruction after the second injury were demoted in rank for 3 to 4 tournaments but overtook the nonoperative treatment group in ranking by 2 years postoperatively; all athletes initially were demoted in rank after the second injury. CONCLUSION: This study is the first to investigate instances of ipsilateral reinjuries and contralateral ACL injuries after ACL reconstruction in professional athletes in heavyweight combat sports. The incidences of ipsilateral reinjury and contralateral ACL injury after ACL reconstruction in professional sumo wrestlers were relatively higher than those reported in previous studies.

Jones Fractures in Sumo Wrestlers: Three Case Reports.

Jones fractures sometimes occur in athletes and are known to have complications, such as nonunion, delayed union, and recurrence, even with treatment. We describe three cases of Jones fractures in sumo wrestlers with treatment-related difficulties. All patients discontinued treatment at their own discretion. The two conservative cases had nonunion or delayed union, and the operative case had a broken screw. However, all patients continued sumo wrestling, with little impact on their careers. The risk factors of Jones fractures in sumo wrestling may be heavy weight, and training or competition characteristics unique to sumo wrestling. In cases of a complete Jones fracture, operative treatment is most commonly selected, as the risk for nonunion or refractures is less than that for conservative treatment. However, in the case of sumo wrestlers, there are risks of infection and problems with treatment compliance. As taking a rest may result in a lowered rank, completing a sufficient duration of treatment is difficult. Treatment is difficult and controversial in sumo wrestlers; all three patients discontinued treatment of their own accord. These cases suggest that it is important to thoroughly inform sumo wrestlers of the treatment options, and to decide the most appropriate treatment method for each patient.

Surgical Treatment of Lumbar Herniated Nucleus Pulposus Combined with Residual Bony Fragment of Apophyseal Ring Fracture in High-Level Athletes†:†A Report of Two Cases.

In this paper, we present 2 cases of herniated nucleus pulposus (HNP) combined with the residual bony fragment of apophyseal ring fracture. HNP typically exists at the narrow lateral recess formed by the bony fragment, and so it has been reported that symptoms may persist. Case 1 was a 22-year-old man, a high-level javelin thrower and Paralympic athlete. He had a history of persistent pain for 4 years due to HNP, and so we performed surgical removal. Case 2 was a 23-year-old male professional baseball player. He was referred to us only 17 days after the onset of pain and presented with muscle weakness, a feature which may prolong the clinical course in addition other features such as pain. Thus, we performed a comparatively quick intervention of surgical removal. In both cases, we had excellent clinical outcomes and better function and performance. In conclusion, in cases with HNP and apophyseal ring separation, surgical intervention in the comparatively early phase can be recommended, particularly if the patients desire quick return to their original level of activity. J. Med. Invest. 66 : 358-361, August, 2019.

Tackler's head position relative to the ball carrier is highly correlated with head and neck injuries in rugby.

OBJECTIVES: To characterise the tackler's head position during one-on-one tackling in rugby and to determine the incidence of head, neck and shoulder injuries through analysis of game videos, injury records and a questionnaire completed by the tacklers themselves. METHODS: We randomly selected 28 game videos featuring two university teams in competitions held in 2015 and 2016. Tackles were categorised according to tackler's head position. The 'pre-contact phase' was defined; its duration and the number of steps taken by the ball carrier prior to a tackle were evaluated. RESULTS: In total, 3970 tackles, including 317 (8.0%) with the tackler's head incorrectly positioned (ie, in front of the ball carrier) were examined. Thirty-two head, neck or shoulder injuries occurred for an injury incidence of 0.8% (32/3970). The incidence of injury in tackles with incorrect head positioning was 69.4/1000 tackles; the injury incidence with correct head positioning (ie, behind or to one side of the ball carrier) was 2.7/1000 tackles. Concussions, neck injuries, 'stingers' and nasal fractures occurred significantly more often during tackles with incorrect head positioning than during tackles with correct head positioning. Significantly fewer steps were taken before tackles with incorrect head positioning that resulted in injury than before tackles that did not result in injury. CONCLUSION: Tackling with incorrect head position relative to the ball carrier resulted in a significantly higher incidence of concussions, neck injuries, stingers and nasal fractures than tackling with correct head position. Tackles with shorter duration and distance before contact resulted in more injuries.

Outcome of Low-Intensity Pulsed Ultrasound (LIPUS) for Opening Wedge High Tibial Osteotomy.

OBJECTIVE: Opening Wedge High Tibial Osteotomy (OWHTO) for knee osteoarthritis and for osteonecrosis has reported good results. Use of low intensity pulsed ultrasound (LIPUS) after OWHTO had become an option for the treatment of OWHTO since April 2016. The purpose of this study was to examine whether LIPUS has an accelerating effect on synostosis after OWHTO. MATERIALS AND METHODS: The control subjects were 24 patients with a total of 26 knees (9 male with knees and 15 female with 17 knees treated) treated with OWHTO only. OWHTO was performed from April 2015 to March 2016 (non-LIPUS control group). The average age of the patients was 61 years. The test subjects were 25 patients with a total of 27 knees (8 male with 9 knees and 17 female with 18 knees treated) treated with OWHTO and LIPUS. OWHTO was performed from April 2016 until the present. LIPUS was started after the surgery (LIPUS + group). The average age was 64.6 years. FTA, ROM, intraoperative open angle, and the time to bone union were examined. RESULTS: There was no difference between the 2 groups in FTA, ROM, and open angle. Synostosis was obtained in 18 knees in the control group (no LIPUS) with an average duration of 8.4 months. The LIPUS + group had a short observation period with none of the patients experiencing bone union. DISCUSSION: The synostosis promoting effect of LIPUS is expected. In this study, there were no bone union cases because of the short observation period. It is necessary to extend the follow-up period, and clarify the utility of LIPUS.

Plantar fascia rupture in a professional soccer player.

We report the case of a 29-year-old male professional soccer player who presented with symptoms of plantar fasciitis. His symptoms occurred with no remarkable triggers and gradually worsened despite conservative treatments including taping, use of insoles, and physical therapy. Local corticosteroid injection was given twice as a further intervention, but his plantar fascia partially ruptured 49 days after the second injection. He was treated conservatively with platelet-rich plasma, and magnetic resonance imaging showed regenerative change of the ruptured fascia. Five months after the rupture, he returned to his original level of training. If professional athletes find it difficult to refrain from athletic activity, as in the present case, the risk of rupture due to corticosteroid injection should not be overlooked.

Anatomic study of the attachment of the medial patellofemoral ligament and its characteristic relationships to the vastus intermedius.

PURPOSE: The aim of this study was to investigate the attachment of the medial patellofemoral ligament (MPFL) using cadaver specimens and establish an anatomic basis for optimal MPFL reconstruction to achieve better patella stability. METHODS: Sixteen knees of eight cadavers were used in this study. The relationship of the MPFL with quadriceps muscles was investigated from outside after removal of the distal part of the vastus medialis and the rectus femoris and then evaluated from intra-articular side after release of lateral margin of the vastus lateralis muscle, patella and patella tendon. RESULTS: The proximal fibres of MPFL were mainly attached to the vastus intermedius tendon, without tight adhesion to the vastus medialis. The distal fibres of MPFL were interdigitated with the deep layer of the medial retinaculum that was attached to the medial margin of the patella tendon. CONCLUSION: These findings imply that MPFL, which was directly attached to the vastus intermedius and patella and indirectly continued to the patella tendon, could keep pulling them medially as one unit and consequently make the patella move smoothly on the trochlea during whole movement of the knee. Clinically, dysfunction of both proximal and distal MPFL fibres should be considered in the diagnosis and treatment of patella instability after traumatic patella dislocation. MPFL reconstruction with both fibres has a possibility to lead ideal function of MPFL and better instability of the patella.

Graft length change and radiographic assessment of femoral drill hole position for medial patellofemoral ligament reconstruction.

PURPOSE: Medial patellofemoral ligament (MPFL) reconstruction has been recognized as a useful treatment method for patella instability. However, the optimal fixation site has not been well investigated, and few reports have examined intraoperative graft length change. The purpose of the study is to evaluate the intraoperative graft length change and femoral drill hole position to find the optimal graft placement. METHODS: The graft length change between the two points on patella and femur was measured using Isotac(®) and Isometric Positioner(®) during passive knee motion in 27 cases of MPFL. The location of Isotac(®) was also evaluated on the 2-directional radiograph. The pre- and postoperative radiographic assessments have been done in order to evaluate the effect of MPFL reconstruction on patellofemoral alignment. RESULTS: There were 10 cases in which the distance between the two points became longer during knee flexion, 8 cases in which it became shorter and the remaining 9 cases in which the distance changed within 2 mm. The femoral drill hole position was assessed assuming that the maximum anterior-posterior (AP) diameter of the femur on the lateral radiograph was defined as 100%. The distance of the femoral tunnel position from the articular surface averaged 50% overall, 46% in the short group, 55% in the longer group and 48% in the isometric group (P < 0.001). Patella height seemingly affected the length change character. The intraoperative length change influenced the early recovery of knee range motion postoperatively. CONCLUSIONS: The femoral tunnel position is reaffirmed to be an essential determinant for the graft length change in the MPFL reconstruction. Both graft length change measurements and intraoperative radiographic assessment are practical for proper graft placement.

Visual analog scale assessment after medial patellofemoral ligament reconstruction: with or without tibial tubercle transfer.

BACKGROUND: We studied the efficacy of medial patellofemoral ligament (MPFL) reconstruction, with or without tibial tubercle (TT) transfer, for recurrent dislocation of the patella, based on subjective functional assessment using the visual analog scale (VAS). METHODS: Forty-two consecutive knees of 40 patients who underwent MPFL reconstruction using a hamstring tendon were followed up for an average of 4.3 years. Twenty-nine knees underwent MPFL reconstruction (MPFL group) and 13 knees underwent MPFL reconstruction combined with medial transfer of TT (TT+MPFL group). Clinical results, including the VAS score at the latest follow-up in both groups, were assessed. RESULTS: An apparent deficit in the range of motion was observed in two cases from the TT+MPFL group. The ratio of negative apprehension test was significantly improved from 3% preoperatively to 79% postoperatively in the MPFL group and from 8% to 69% in the TT+MPFL group. The Lysholm scores were significantly improved from 70 points preoperatively to 92 points postoperatively in the MPFL group and from 72 points to 90 points in the TT+MPFL group. There was no significant difference between the two groups in the ratios of negative apprehension tests and the Lysholm scores after surgery as well as before surgery. In the VAS assessment, the MPFL group scored significantly higher than the TT+MPFL group in "Japanese full sitting" (average score 92 vs 62). The scores of the two groups were not significantly different in any of the other items, although the total average score was significantly higher in the MPFL group (91 vs 81). CONCLUSIONS: MPFL reconstruction without TT transfer achieved satisfactory results including high scores on subjective functional assessments without disadvantage caused by the TT transfer. Isolated MPFL reconstruction has been suggested to be a useful treatment method for recurrent dislocation of the patella.