Effect of pre-operative HbA1c and blood glucose level on the surgical site infection after lumbar instrumentation surgery.

BACKGROUND: This study aims to investigate the effect of pre-operative hemoglobin A1c (HbA1c) and pre-operative blood glucose control on the rate of surgical site infection (SSI) after posterior lumbar instrumentation surgery in diabetes mellitus (DM) patients. METHODS: A total of 1046 patients who had undergone posterior lumbar instrumentation surgery were reviewed. Based on pre-operative HbA1c, patients were divided into three groups: non-DM group, low HbA1c group (HbA1c < 7.0 % in DM) and high HbA1c group (≥7.0). As well, based on the status of blood glucose control in DM patients immediately before surgery, patients were divided into two groups: good control group (post-prandial blood glucose [PBG] < 200 mg/dl) and poor control group (≥200). The rate of SSI was compared among these groups. RESULTS: SSI occurred in 1.9 % in non-DM group, 2.4 % in low HbA1c group, and 9.3 % in high HbA1c group. Compared with non-DM group, high HbA1c group had significantly higher rate of SSI (p = 0.001). There was not statistically different between non-DM and low HbA1c groups (p = 0.550). SSI occurred in 2.2 % in good control group, and 10.2 % in poor control group. The rate of SSI was significantly lower in good control group (p = 0.013). CONCLUSION: This study showed that the rate of SSI after posterior lumbar instrumentation surgery tend to be higher in DM patients with high HbA1c. However, the rate might be reduced to the same level as that of non-DM group by lowering PBG to <200 mg/dl immediately before surgery.

Arthroscopic Bankart repair with additional footprint fixation using the double-row technique at the 4 o'clock position anatomically restored the capsulolabral complex and showed good clinical results.

PURPOSE: To investigate the clinical outcome and magnetic resonance imaging (MRI) findings after arthroscopic Bankart repair with additional double anchor footprint fixation (DAFF) at the 4 o'clock position, where the native footprint is widest anatomically, for recurrent anterior shoulder instability. METHODS: Forty-two patients (mean age 27.0 years) with recurrent anterior shoulder instability and without severe glenoid bone defects underwent arthroscopic Bankart repair with additional DAFF at the 4 o'clock position. Using three standard portals, single-row repair was performed at the 2, 3, and 5 o'clock positions, and DAFF with the suture bridging technique was conducted at the 4 o'clock position. MRI was performed preoperatively and at 6 months postoperatively. Patients with follow-up periods of ≥1 year were included in the present study and clinically evaluated at the final follow-up. The morphology at the 2 and 4 o'clock positions on radial MRI slices was compared between the preoperative and 6-month postoperative scans, and the footprint of the repaired capsulolabral complex at 6 months postoperatively was compared between the 2 and 4 o'clock positions. RESULTS: The average follow-up period was 19.5 ± 6.2 months. The rates of dislocation recurrence and positive apprehension test results were 2.4 and 4.8%, respectively. External rotation was restricted by 3.5°. The University of California at Los Angeles and Rowe scores at the final follow-up were 34.5 ± 1.0 points and 97.2 ± 5.7 points, respectively, representing significant improvements over the preoperative scores (p < 0.01). Although the capsulolabral complex at 6 months postoperatively was firmly repaired at both the 2 and 4 o'clock positions compared to its preoperative state, the footprint of the restored capsulolabral complex was wider at the 4 o'clock position than at the 2 o'clock position (p < 0.01). CONCLUSIONS: Additional DAFF at the 4 o'clock position improved the glenohumeral stability and function of the shoulder joint. This study suggests that this technique is a reliable and useful treatment for shoulder instability. LEVEL OF EVIDENCE: IV.

Unique environmental Symbiodiniaceae diversity at an isolated island in the northwestern Pacific.

Dinoflagellates in the family Symbiodiniaceae are intensively investigated as algal symbionts of corals and other invertebrates, underpinning coral reef ecosystems as primary producers. Diversity, including regional diversification, of free-living communities is less studied. In this study, an environmental Symbiodiniaceae community at an isolated island, Okinotori Island, Japan, was investigated to determine whether the community is endemic or common with other locations near continents and major ocean currents. Symbiotic algae in common corals at the island were the same type as those of the corals from other Japanese waters. In the environmental samples, genera Symbiodinium (formerly clade A), Cladocopium (clade C), Durusdinium (clade D), and clades F (including Freudenthalidium), G, and I, were identified through analysis of internal transcribed spacer region 2 of nuclear ribosomal RNA gene (ITS2) sequences. Interestingly, some sequences found were genetically different from those of previously reported genera/clades. These unknown sequences were genetically included in the Symbiodiniaceae linage, but they were differentiated from the previously known nine clades. The sequences formed a cluster in the phylogenetic tree based on 28S nrDNA. These sequences were thus considered members of a novel clade in the family (clade J). In total, 120 kinds of ITS2 sequences were produced; while 10 were identical to previously reported sequences, the majority were highly divergent. These genetically unique Symbiodiniaceae types, including novel clade J, may have evolved in isolation and reflect the environmental characteristics of the Okinotori Island.

Increased Stiffness of Rotator Cuff Tendons in Frozen Shoulder on Shear Wave Elastography.

OBJECTIVES: To evaluate the stiffness and morphologic characteristics of the capsule, rotator cuff tendons and muscles, coracohumeral ligament (CHL), and long head of the biceps in patients with frozen shoulder using shear wave elastography (SWE) with B-mode ultrasound. METHODS: Thirty-two patients with frozen shoulder were divided into freezing and frozen phases. All patients had limitations of their range of motion without rotator cuff tears. Stiffness was measured by SWE in the supraspinatus (SSp) tendon, infraspinatus (ISp) tendon, SSp muscle, ISp muscle, teres minor muscle, upper and lower trapezius muscles, posterior capsule, CHL, and long head of the biceps. The posterior capsule and CHL thicknesses were also investigated with B-mode ultrasound. All values were compared in the affected and unaffected shoulders in each phase. RESULTS: The SWE values for the SSp and ISp tendons in the freezing phase and the CHL in the frozen phase were significantly greater on the affected side than the unaffected side (mean ± SD, 280.4 ± 125.3 versus 178.1 ± 73.3, 318.4 ± 110.7 versus 240.8 ± 91.5, and 287.2 ± 135.3 versus 214.1 ± 91.1 kPa, respectively; P < .05). The posterior capsule in both the freezing and frozen phases and the CHL in the frozen phase were significantly thicker on the affected side than the unaffected side (1.3 ± 0.2 versus 0.9 ± 0.3, 1.2 ± 0.4 versus 0.9 ± 0.3, and 4.4 ± 1.4 versus 3.3 ± 1.1 mm; P < .01). CONCLUSIONS: The SWE values of the both SSp and ISp tendons increased in the freezing phase, and that of the CHL also increased in the frozen phase. Not only the change in thickness of the capsule but also the change in stiffness of the rotator cuff may correlate with frozen shoulder.

Anatomic Analysis of the Attachment of the Posteroinferior Labrum and Capsule to the Glenoid: A Cadaveric Study.

PURPOSE: To measure the height of the posteroinferior glenohumeral ligament (PIGHL) attachment to the labrum and the depth of the posteroinferior labrum to the glenoid, macroscopically, and to investigate the morphology of the attachment of the posteroinferior labrum to the glenoid, histologically. METHODS: Fifty cadaveric shoulders without exposed subchondral bone on the glenoid and detached posterior labrum were used. We examined the frequency of the heights of the PIGHL attachments to the labrum and the length of the labral attachment on the glenoid rim at the 7, 8, 9, and 10 o'clock positions, macroscopically. According to morphology of the histological labral attachments, it was divided into 3 groups. Labra attached on the articular surface and the glenoid neck were defined as the SN type, while labra attached only to the glenoid neck constituted labra attached to the bone and side of the articular cartilage (Nc type) and labra attached only to bone (Nb type). RESULTS: The PIGHL attached from 7 o'clock to 9 o'clock in 48 shoulders (96%). The mean labral attachment at the 7 o'clock position was 6.3 ± 1.0 mm (range, 4.6-9.4 mm), which was significantly longer than at the other positions (P < .05). Histologically, the frequency of SN type attachment was 49 (98%) shoulders at the 7 o'clock position. CONCLUSIONS: The PIGHL attached between 7 and 9 o'clock in 96% of the shoulders. In 98% of the shoulders, the labrum did not attach to the articular surface, but attached to both the articular cartilage and the bone of the glenoid neck at 7 o'clock. CLINICAL RELEVANCE: The posteroinferior labrum should be repaired widely at the 7 o'clock position and not on the articular surface because the labrum attached anatomically to the glenoid neck.

The kinematics of 1-on-1 rugby tackling: a study using 3-dimensional motion analysis.

BACKGROUND: Although past studies using video analysis indicated that the arm tackle and head-in-front shoulder tackle are possible risks for shoulder dislocation, the underlying mechanisms of tackling-related shoulder dislocation have not been sufficiently investigated. This study aimed to analyze the kinematic aspects of these tackling motions in 1-on-1 tackles in an experimental setting using a 3-dimensional motion-capture system. METHODS: A total of 65 one-on-one tackles were recorded using a marker-based, automatic, digitizing motion-capture system. A documented tackle was classified into 1 of 3 types, which was decided based on the first point of contact on the ball carrier and the head position at the time of impact: shoulder tackle (reference tackle), arm tackle, and head-in-front tackle. The orientations of the head, trunk, and shoulder at impact were calculated and statistically compared with each other. RESULTS: The distribution of tackles recorded in this study was as follows: 38 shoulder, 23 arm, and 4 head-in-front tackles. In comparison with the shoulder tackle as a reference, shoulder abduction on the side of impact was higher in both the arm and head-in-front tackles, while shoulder external rotation was lower in the head-in-front tackles. In the latter type of tackle, significant decreases in neck extension and ipsilateral neck rotation were also indicated. CONCLUSION: The kinematics in both the arm tackle and the head-in-front tackle is significantly different from that in the shoulder tackle and may represent a distinct risk factor for shoulder dislocation.

Accelerated Return to Play for Professional Rugby Players After Facial Fractures.

BACKGROUND: Facial fractures may result in a significant time away from competition for professional rugby players. An understanding of the return-to-play times is an integral part of clinical decision making when treating professional athletes. A period of 8 to 12 weeks has been conventionally recommended for returning to collision sports after facial fractures. The conventional time to return to sports of 8 to 12 weeks is usually too long for professional players. However, the time of return to play after such facial fractures in elite athletes has not been well described. PURPOSE: To investigate the return to play after facial fractures in professional rugby players with an accelerated rehabilitation protocol. METHODS: Ten professional rugby players with facial fractures were identified and analyzed. The authors investigated the number of days required to return to training and full-contact play according to the trauma type. The authors also determined the presence or absence of refractures and sequelae. RESULTS: The average age of the patients was 26.9 years. Medial orbital wall fractures were the most represented pattern, followed by orbital floor fractures and zygomatic arch fractures. The players returned to jogging after 9.9 days, to sports-specific training after a mean of 10.8 days, and to full-contact training after 18.3 days. There were no cases of refractures and sequelae. CONCLUSION: Players were able to return to their regular rugby activities, earlier than the time commonly allowed to return to full activity.

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.

Shear Wave Elastography Can Predict Passive Stiffness of Supraspinatus Musculotendinous Unit During Arthroscopic Rotator Cuff Repair for Presurgical Planning.

PURPOSE: To determine the feasibility of shear wave elastography (SWE) with B-mode ultrasound in predicting the stiffness of the rotator cuff muscle before arthroscopic rotator cuff repair to evaluate the difficulty of the surgical procedure, as well as to compare SWE with the Goutallier stage on magnetic resonance imaging (MRI). METHODS: Thirty-eight patients with a full-thickness supraspinatus tear requiring arthroscopic rotator cuff repair participated. The Goutallier stage of fatty infiltration on MRI was measured before surgery, as was the SWE modulus of the anterior superficial, anterior deep, posterior superficial, and posterior deep (PD) regions of the supraspinatus muscle. To measure the stiffness of the supraspinatus musculotendinous unit during surgery, the supraspinatus tendon was axially stretched until the anatomic insertion site was reached, and force per deformation was recorded. The correlation between stiffness of the supraspinatus and SWE value in each region of the supraspinatus muscle or Goutallier stage was determined. In addition, patients were divided into 2 groups: (1) In the complete footprint coverage group, greater than 50% of the footprint was covered during the stiffness measurement, and (2) in the incomplete footprint coverage group, less than 50% of the footprint was covered during the stiffness measurement. Differences in SWE value and Goutallier stage were measured between the 2 groups. RESULTS: The best correlation of stiffness with the SWE modulus of the PD muscle of the supraspinatus was R = 0.69, and the correlation of stiffness with the Goutallier stage on MRI was R = 0.48. The SWE value of the PD region was greater in the incomplete footprint coverage group than in the complete footprint coverage group, although the Goutallier stage was not significantly different. CONCLUSIONS: The highest correlation with stiffness of the supraspinatus musculotendinous unit was with the SWE modulus of the PD muscle, as compared with SWE evaluation of the other regions or the Goutallier stage on MRI. Ultrasound SWE can predict the stiffness of the supraspinatus musculotendinous unit best. CLINICAL RELEVANCE: Rotator cuff retraction adds difficulty to arthroscopic rotator cuff repair. Ultrasound SWE may be used for presurgical planning.

Range limitation in hip internal rotation and fifth metatarsal stress fractures (Jones fracture) in professional football players.

PURPOSE: To identify unknown risk factors associated with fifth metatarsal stress fracture (Jones fracture). METHODS: A case-controlled study was conducted among male Japanese professional football (soccer) players with (N = 20) and without (N = 40) a history of Jones fracture. Injury history and physical examination data were reviewed, and the two groups were compared. Univariate and multivariate logistic regression controlling for age, leg dominance and body mass index were used to obtain odds ratios (ORs) and 95% confidence intervals (CIs) to describe the association between physical examination data and the presence or absence of Jones fractures. RESULTS: From 2000 to 2014, among 162 professional football club players, 22 (13.6%; 21 Asians and one Caucasian) had a history of Jones fracture. Thirteen out of 22 (60%) had a Jones fracture in their non-dominant leg. The mean range of hip internal rotation (HIR) was restricted in players with a history of Jones fracture [25.9° ± 7.5°, mean ± standard deviation (SD)] compared to those without (40.4° ± 11.1°, P < 0.0001). Logistic regression analyses demonstrated that HIR limitation increased the risk of a Jones fracture (OR = 3.03, 95% CI 1.45-6.33, P = 0.003). Subgroup analysis using data prior to Jones fracture revealed a causal relationship, such that players with a restriction of HIR were at high risk of developing a Jones fracture [Crude OR (95% CI) = 6.66 (1.90-23.29), P = 0.003, Adjusted OR = 9.91 (2.28-43.10), P = 0.002]. In addition, right HIR range limitation increased the risks of developing a Jones fracture in the ipsilateral and the contralateral feet [OR = 3.11 (1.35-7.16) and 2.24 (1.22-4.12), respectively]. Similarly, left HIR range limitation increased the risks in the ipsilateral or the contralateral feet [OR (95% CI) = 4.88 (1.56-15.28) and 2.77 (1.08-7.08), respectively]. CONCLUSION: The restriction of HIR was associated with an increased risk of developing a Jones fracture. Since the HIR range is a modifiable factor, monitoring and improving the HIR range can lead to prevent reducing the occurrence of this fracture. LEVEL OF EVIDENCE: III.

Return to Play of Rugby Players After Anterior Cruciate Ligament Reconstruction Using Hamstring Autograft: Return to Sports and Graft Failure According to Age.

PURPOSE: To assess return to play and the frequencies of graft failure in rugby players after anterior cruciate ligament (ACL) reconstruction using a hamstring autograft augmented with an artificial ligament and to compare outcomes between rugby players aged <20 and ≥20 years over the long term. METHODS: A consecutive series of 146 rugby players who underwent ACL reconstruction with a hamstring autograft augmented with an artificial ligament were retrospectively reviewed. The study population was further divided into 2 groups aged <20 years and >20 years and compared. RESULTS: Twenty-five patients could not be followed up, and 121 (83%) were evaluated. Most patients (90%, <20 years; 92%, ≥20 years) returned to play after ACL reconstruction. At an average follow-up period of 56.5 months, 16% of the patients sustained an ACL graft rupture. Regarding age, <20 years (n = 58, 48%) and ≥20 years (n = 63, 52%), younger players had a significantly higher failure rate (23% vs 5%, respectively; P = .006) and a shorter time to failure (22.8 ± 13.2 vs 35.4 ± 15.4 months, respectively; P = .006) than older players. CONCLUSIONS: Rugby players were likely to return to play after ACL reconstruction with a hamstring autograft. However, there was a higher risk of graft failure in younger players than in older players. On the basis of this study, we conclude that the hamstring autograft may not be an appropriate graft source to use in a younger active population, including rugby players. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Infrared spectroscopy of phenol-triethylsilane dihydrogen-bonded cluster and its cationic analogues: intrinsic strength of the Si-H···H-O dihydrogen bond.

Spectroscopic and theoretical investigations have been carried out for neutral phenol-triethylsilane clusters to reveal an intrinsic nature of the Si-H···H-O type dihydrogen bond. On the basis of the laser-induced fluorescence and infrared spectra, four isomers are identified. Three of them have a structure in which the dihydrogen bond and the dispersion interaction are competing in the stabilization of the cluster. However, the other isomer is found to have a distinct structure in which the dihydrogen bond is much stronger than the other isomers. In addition to the neutral clusters, cationic phenol(+)-diethylmethylsilane and phenol(+)-triethylsilane clusters are investigated by infrared photodissociation spectroscopy. It is found that the dihydrogen bond is the dominant intermolecular interaction in these clusters. On the basis of the red shifts of the OH stretching bands, it is revealed that the strength of the Si-H···H-O dihydrogen bond is stronger than that of the π-type hydrogen bond. The proton affinities of triethylsilane and diethylmethylsilane estimated by the theoretical calculation are larger than those of benzene and ethylene. These results are consistent with our experimental observations.

Incidence of and risk factors for traumatic anterior shoulder dislocation: an epidemiologic study in high-school rugby players.

BACKGROUND: The incidence of reinjuries due to glenohumeral instability and the major risk factors for primary anterior shoulder dislocation in youth rugby players have been unclear. PURPOSE: The purpose of this study was to investigate the incidence, mechanisms, and intrinsic risk factors of shoulder dislocation in elite high-school rugby union teams during the 2012 season. METHODS: A total of 378 male rugby players from 7 high-school teams were investigated by use of self-administered preseason and postseason questionnaires. RESULTS: The prevalence of a history of shoulder dislocation was 14.8%, and there were 21 events of primary shoulder dislocation of the 74 overall shoulder injuries that were sustained during the season (3.2 events per 1000 player-hours of match exposure). During the season, 54.3% of the shoulders with at least one episode of shoulder dislocation had reinjury. This study also indicated that the persistence of glenohumeral instability might affect the player's self-assessed condition, regardless of the incidence during the current season. By a multivariate logistic regression method, a history of shoulder dislocation on the opposite side before the season was found to be a risk factor for contralateral primary shoulder dislocation (odds ratio, 3.56; 95% confidence interval, 1.27-9.97; P = .02). CONCLUSIONS: High-school rugby players with a history of shoulder dislocation are not playing at full capacity and also have a significant rate of reinjury as well as a high risk of dislocating the other shoulder. These findings may be helpful in deciding on the proper treatment of primary anterior shoulder dislocation in young rugby players.

Do stingers affect scapular kinematics in rugby players?

BACKGROUND: Scapular dyskinesis is observed in subjects with pathologic conditions of the shoulder; however, there is limited information about the factors related to scapular dyskinesis among participants in rugby. The purpose of this study was to investigate the incidence, reliability, and relationships between scapular dyskinesis and variables related to the shoulder in high-school rugby players. METHODS: A total of 164 Japanese high-school rugby players were evaluated with questionnaires, physical examinations, and a video analysis during their preseason. After evaluation of the inter-rater reliability of a classification of scapular dyskinesis, the outcomes were analyzed to assess the relationships between scapular dyskinesis and other variables during the preseason. The data were assessed with a logistic regression analysis calculating the odds ratios (OR). RESULTS: The inter-rater reliability among 3 blinded observers based on the Fleiss κ value and percentage agreement was .52 and 79.0%, respectively, which indicates that the method is moderately reliable. Scapular dyskinesis was identified in 16 (10.1%) shoulders among 159 players, with type I being prominent. A multivariate logistic regression analysis revealed that a type I dyskinesis was significantly associated with a past history of stingers with projected pain to the affected side of the shoulder (OR, 3.7) and the player's competitive grade at the time of the survey (OR, 3.9). CONCLUSIONS: Scapular dyskinesis is significantly associated with a past history of stingers. This suggests that stingers are a causative factor of scapular dyskinesis in the rugby population. Our method of evaluating scapular dyskinesis in collision athletes exhibits moderate reliability.

Arthroscopically Assisted Coracoclavicular (CC) Stabilization Using a Suture Button Device for Lateral Clavicle Fractures with CC Ligament Injury.

Background: Lateral clavicle fractures represent approximately 10-15% of all clavicle fractures. However, controversy exists regarding the optimal surgical treatment because of instability associated with the coracoclavicular (CC) ligament injury and a small lateral fragment. The purpose of this study was to evaluate the radiological and clinical outcomes of arthroscopically assisted CC stabilization using a suture button device for lateral clavicle fractures accompanied by CC ligament injury. Methods: A retrospective observational study involved six patients with modified Neer type IIB fractures, which were treated with the technique and followed for 12 months. Postoperative range of motion (ROM) and X-rays were evaluated every 3 months. Shoulder functional scores (University of California Los Angeles score, Japanese Orthopedics Association score) and visual analog scale (VAS) scores for pain (at rest, at night, and during motion) and for satisfaction were analyzed 12 months after surgery. Results: Early phase ROM recovery and excellent outcomes were achieved. All patients achieved bone union. Slight superior clavicle displacement and bone hole dilation occurred with no critical complications. Conclusions: Arthroscopically assisted CC stabilization with a suture button device for unstable lateral clavicle fractures can produce satisfactory radiological and clinical results.

Reference intervals of serum hyaluronic acid corresponding to the radiographic severity of knee osteoarthritis in women.

BACKGROUND: While serum levels of hyarulonic acid (sHA) is known to be useful for a burden of disease biomarker in knee OA, it is far from practical. The reference intervals must be established for biomarkers to be useful for clinical interpretation. The aim of this study was to establish the reference intervals of sHA corresponding to the radiographic severity of knee OA for elucidating whether sHA can be useful as a burden of disease marker for individual patient with knee OA. METHODS: 372 women with Kellgren & Lawrence grade (K/L) 1 through 4 painful knee OA were enrolled in this study. The patients included 54 with K/L 1, 96 with K/L 2, 97 with K/L 3, and 118 with K/L 4. Serum samples were obtained from all subjects on the day that radiographs taken. A HA binding protein based latex agglutination assay that employed an ELISA format was used to measure sHA. Age and BMI adjusted one way ANOVA was used to set the reference intervals of sHA. RESULTS: The reference intervals for sHA corresponding to the patients with K/L 4 (49.6 - 66.5 ng/ml) was established without any overlap against to those with K/L 1, 2 and 3, while those with K/L 1, 2 and 3 showed considerable overlap. CONCLUSIONS: These results indicate that sHA can be available as a burden of disease marker for the individuals with severe knee OA (K/L 4), while it is not for those with primary to moderate knee OA (K/L 1-3).

Computed tomography osteoabsorptiometry for assessing the density distribution of subchondral bone as a measure of long-term mechanical stress in the "rugby shoulder".

BACKGROUND: Rugby is a collision sport with a high risk of shoulder injury. Although traumatic anterior shoulder instability is common, the long-term effects of rugby and joint instability on the shoulder have not been described; thus, this study assessed the effects of rugby itself, and joint instability, on the glenoid cavity. MATERIALS AND METHODS: Both sides of the shoulders from 25 rugby players and 17 control patients with unilateral shoulder instability were prospectively evaluated by means of computed tomography osteoabsorptiometry, which represents the distribution of mineralization in subchondral bone plate (DMSB) as a marker of the long-term loading history of a joint. For the quantitative analysis, intergroup differences of maximum Hounsfield unit (HU) values in 7 areas on the glenoid were assessed in the uninjured intact shoulder to characterize the influence of rugby. Side-to-side differences of the HUs in each area were assessed in each participant to characterize the effects of shoulder instability. For the qualitative analysis, associations between the patterns of each DMSB and each group were assessed by means of correspondence analysis. RESULTS: All examined areas on the glenoid had a significantly higher HUs in rugby players. Shoulder instability affected the HUs in both groups. A qualitative analysis demonstrated that the maximum HU tended to be shifted more inferiorly in rugby players and in the unstable shoulders. CONCLUSIONS: Rugby affects the shoulder joint, regardless of any history of instability, suggesting that "rugby shoulder" tends to involve degenerative changes, such as osteoarthritis or labral tears.

Association of Lumbar Spondylolytic Spondylolisthesis With the Incidence and Prognosis of Anterior Ring Apophyseal Abnormalities of the Vertebrae in Young Gymnasts.

Background: Although anterior apophyseal abnormalities of the vertebrae and spondylolytic spondylolisthesis (SS) are prevalent in gymnasts during growth spurts, no studies have examined the relationship between apophyseal abnormalities and SS. Hypothesis: A significant relationship will exist between anterior apophyseal abnormalities and SS in young gymnasts. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 306 gymnasts (123 male, 183 female; age range, 6-28 years) with >2 weeks of back pain were enrolled in this study. Apophyseal abnormalities were evaluated using radiography. In the primary analysis, multiple logistic regression analysis was performed to assess the odds ratio (OR) for multivariate factors (age, body mass index, sex, skeletal maturity, competitive level, and presence of spondylolysis or SS) influencing the incidence of apophyseal abnormalities. In the secondary analysis, 90 of the 306 gymnasts were followed up radiographically for a minimum of 2 years, and factors contributing to the worsening of apophyseal abnormalities were identified. Results: In the primary analysis, the chi-square test revealed a relationship between anterior ring apophyseal abnormalities and SS at the L5-S1 segment (OR, 7.6). Multiple logistic regression analysis demonstrated that the presence of SS at L5-S1 (OR, 9.5) and competitive level (international: OR, 6.7; national: OR, 4.5) correlated with the incidence of apophyseal abnormalities. The secondary analysis identified the presence of SS at L5-S1 (OR, 5.9) as a significant factor contributing to the worsening of apophyseal abnormalities. Conclusion: The presence of SS was a factor affecting the incidence and prognosis of anterior apophyseal abnormalities.

Risk Factors for Concussion in Under 18, Under 22 and Professional Men's Rugby Union: A Video Analysis of 14,809 Tackles.

OBJECTIVE: This study aimed to identify the risk factors for tackle-related concussion observed in matches involving under (U) 18, U 22 and professional men's Rugby Union players through video analysis. STUDY DESIGN: Descriptive epidemiology study. METHODS: Twenty Rugby Union matches each for high school (U18), university/college (U22) and professional (Elite) were randomly selected from 202 matches in the 2018/2019 season. Both one-on-one and tackles involving multiple tacklers were analyzed for the 60 matches. The 28 categorical and continuous variables (e.g., tackle characteristics and duration before the tackle) were applied as risk factors to a least absolute shrinkage and selection operator (Lasso) regression analysis. To identify high-risk situations, a simulation model with coefficients obtained from the Lasso regression was used. Statistical analysis was conducted according to tackle direction. RESULTS: A total of 14,809 tackles and 41 concussions involving 1800 players were included in the analyses. The incidence rate of concussions (injuries/1000 tackles) was greater in Elite players (4.0) compared with U18 (1.9) and U22 (2.4) players. The factors most highly associated with concussions were head-in-front tackles (where the tackler's head is placed forward, impeding a ball carrier's forward movements, 11.26/1000 tackles), and were more often observed among U18 players. A simulation model predicted that the highest risk tackle situation in Elite players was a head-in-front, side-on tackle below the hip of the ball carrier (predicted incidence rate 18.07/1000 tackles). CONCLUSION: The risk factors associated with concussion need to be assessed cautiously. Avoiding head-in-front, side-on tackles to the lower extremities of a ball carrier should be considered to reduce injury risks.

Does scapular dyskinesis affect top rugby players during a game season?

BACKGROUND: Scapular dyskinesis represents a considerable risk of shoulder injury to overhead athletes; however, there is a shortage of detailed epidemiologic information about scapular dyskinesis among the participants in collision sports. PURPOSE: To describe the incidence and relationship of scapular dyskinesis to shoulder discomfort and variables related to the shoulder in top rugby players. METHODS: One hundred twenty top rugby football players in Japan were evaluated by means of questionnaires, physical examinations, and a video analysis during their preseason. Data were assessed by a logistic regression analysis calculating odds ratios. The primary outcome was processed to assess the relationship between scapular dyskinesis and other variables at the preseason. The secondary outcome was processed to assess an influence of scapular dyskinesis to shoulder discomfort during their regular season that were reassigned by second questionnaires. RESULTS: Scapular dyskinesis was identified in 33 (32%) shoulders, and type III was prominent. Scapular dyskinesis was significantly associated with shoulder discomfort (OR [odds ratio] = 4.4), and was also associated with variables of the affected shoulder. In addition, the players with asymptomatic scapular dyskinesis at the preseason would have high incident with shoulder discomfort during their regular season (OR = 3.6). CONCLUSIONS: Scapular dyskinesis was associated significantly with both subjective and objective symptoms of the affected shoulder. These appearances may be of particular relevance in the early screening of chronic shoulder disorders in the rugby population. Further study to investigate and evaluate its reliability is needed to characterize its impact on the participants in collision sports.