Publications by authors named "Morihito Tokai"

Background: There remain arguments regarding whether fatty degeneration of the rotator cuff muscles improves following rotator cuff repair. The purpose of this study was to prospectively investigate changes in fatty degeneration of the rotator cuff muscles, quantitatively measured on magnetic resonance imaging (MRI) with use of transverse relaxation time (T2) mapping techniques, and to assess the relationship between these changes and clinical outcomes.

Methods: Patients were included if they were scheduled for arthroscopic rotator cuff repair using the suture-bridge technique between June 2014 and December 2015, underwent preoperative MRI including the T2 mapping sequence, and consented to participate in the study.

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Purpose: To investigate and compare the pathologies and clinical outcomes of patients with traumatic anterior shoulder instability who underwent arthroscopic stabilization at 40 years or older between shoulders with initial dislocation before age 40 years and at 40 years or after.

Methods: Shoulders that underwent arthroscopic stabilization for recurrent traumatic anterior shoulder instability at 40 years or older with a minimum of 2-year follow-up were included. The subjects were divided into 2 groups according to age at initial dislocation after propensity score matching to reduce potential bias: younger than 40 years (group 1) and 40 years or older (group 2).

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Background: No consensus has been reached on the return to sports or physical work after shoulder arthroplasty due to a shortage of literature. The purpose of this study was to investigate return to sports or physical work after anatomical total shoulder arthroplasty (aTSA) and reverse shoulder arthroplasty (RSA), as well as the clinical and radiographic outcomes.

Methods: The inclusion criteria were as follows: 1) aTSA or RSA between 2012 and 2017, and 2) patients who preoperatively participated in sports or physical work.

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Purpose: To retrospectively investigate the mid-term outcomes after arthroscopic repair of isolated subscapularis tears with a relatively large number of patients and to compare them by tear size.

Methods: Medical records were reviewed for patients who underwent arthroscopic rotator cuff repair between 2010 and 2017 at our institute. The inclusion criterion was isolated subscapularis tears that underwent arthroscopic rotator cuff repair.

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Background: Teres minor atrophy can be seen in shoulders both with and without a rotator cuff tear, even among the young population. The purpose of this study was to retrospectively investigate the incidence of teres minor atrophy in young and middle-aged patients with or without a rotator cuff tear.

Methods: Patient records were reviewed to identify 10-39-year-old patients (Group Y) and 60-69-year-old patients (Group O) who underwent MRI because of shoulder disorders.

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Background: Boileau et al have reported on the unstable, painful shoulder (UPS), which was defined as painful shoulders without any recognized anteroinferior subluxations or dislocations that were associated with roll-over lesions (ie, instability lesions) on imaging or at arthroscopy. However, they included various pathologies, probably due to the ambiguity in their definitions of UPS. We redefined UPS as follows: (1) shoulder pain during daily or sports activities, (2) traumatic onset, (3) no complaint of shoulder instability, and (4) soft-tissue or bony lesions, such as Bankart or humeral avulsion of glenohumeral ligament lesion, confirmed by arthroscopy.

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Purpose: We assessed hypertrophy of preserved long head of the biceps tendon (LHBT) and vascularity in the bicipital groove after arthroscopic rotator cuff repair in ≤55-year-old patients and compared postoperative pain between shoulders with or without vascularity in the bicipital groove.

Methods: Patients who underwent arthroscopic rotator cuff repair between 2015 and 2017 were reviewed. Inclusion criteria were arthroscopic rotator cuff repair and ≤55 years old.

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Background: Few studies on the outcomes of anatomic total shoulder arthroplasty (aTSA) in Asian populations have been reported. In addition, approximately one-third of primary aTSA were performed for patients 80 years or older in Japan, but the indication of aTSA for the primary shoulder osteoarthritis in the elderly population remained unclear. The purposes of this study were (1) to investigate clinical outcomes of aTSA in Japanese patients with primary glenohumeral osteoarthritis and (2) to compare clinical outcomes between patients 80 years or older and 70 years or younger.

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Background: Various factors may be related to outcomes of reverse shoulder arthroplasty (RSA) including patient and surgical factors. Differences in shoulder kinematics might be associated with poor function after RSA; however, kinematic differences between shoulders with good or poor elevation have not been elucidated. The purpose of this study was to compare RSA kinematics between shoulders with good or poor elevation.

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Background: Recently, to treat the long head of the biceps tendon lesions in addition to rotator cuff repair has been recommended. However, the differences in clinical outcomes between biceps tenotomy and tenodesis for middle-aged and elderly females remains unclear. The purpose of this study was to compare the outcomes of biceps tenotomy and soft-tissue tenodesis that were performed concurrently with arthroscopic rotator cuff repair in ≥60-year-old females.

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Background: Many surgeons prefer bony stabilization including Bristow or Latarjet procedures for shoulder instability in collision athletes, even though several potential complications have been reported. There has been a limited number of studies on the midterm outcomes of arthroscopic soft tissue stabilization for anterior shoulder instability in competitive collision athletes.

Purpose: To assess the outcomes of arthroscopic soft tissue stabilization in combination with selective augmentation procedures for collision athletes with traumatic anterior shoulder instability.

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Background: Scapular notching is a frequently observed complication after reverse shoulder arthroplasty. Impingement of the humeral plastic insert against the scapular neck is believed to be the cause of notching. There have been no in vivo studies that analyzed the positional relationship between the scapular neck and humeral insert.

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Purpose: The purpose of this study was to investigate the clinical and radiographic outcomes of arthroscopic iliac bone grafting with capsulolabral reconstruction for severe glenoid bone loss with a minimum of 5 years' follow-up.

Methods: The inclusion criterion was shoulders that underwent arthroscopic iliac bone grafting for >20%-25% glenoid defect between January 2007 and April 2014, and the exclusion criterion was <5 years' follow-up. Iliac crest bone grafts of approximately 2.

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Background: The choice of surgical option for unstable large capitellar osteochondritis dissecans (OCD) lesions in skeletally immature athletes remains controversial.

Purpose/hypothesis: The purpose was to investigate functional and radiographic outcomes after arthroscopic fragment resection and osteochondral autograft transplantation (OAT) for unstable large capitellar OCD lesions in skeletally immature athletes with a minimum 5 years' follow-up. We hypothesized that the outcomes after OAT for large capitellar OCD lesions would be superior to those after arthroscopic fragment resection.

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Distal biceps tendon ruptures have been reported to be associated with narrowing of the proximal radioulnar space. There have been no studies that three-dimensionally measured the distance between the bicipital tuberosity and the proximal ulna during active motion. The purpose of this study was to three-dimensionally measure the proximal radioulnar space during active forearm pronation in healthy subjects.

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Background: Superior labral anterior-posterior (SLAP) lesions are common among elite gymnasts and throwing athletes. Although SLAP lesions in throwers are well-described in the literature, no study has described the characteristics of SLAP lesions in gymnasts. We aimed to reveal the characteristics of SLAP lesions in gymnasts by comparing the location and extension of these lesions between gymnasts and throwers.

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Background: Type 2 failure is a big issue after suture-bridge rotator cuff repair, which may be because of stress concentration at the medial row stitches. We have been performing medial knot-tying after suture-bridge lateral row repair to avoid the stress concentration. This study aimed to evaluate clinical and radiological outcomes after arthroscopic rotator cuff repair using this technique.

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Background: No reports have been published on the clinical outcomes, including return to sport, after rotator cuff repair in middle-aged and elderly swimmers with rotator cuff tears.

Purpose: To retrospectively investigate clinical outcomes and return to sport after arthroscopic rotator cuff repair in middle-aged and elderly swimmers.

Study Design: Case series; Level of evidence, 4.

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Purpose: To investigate the incidence of axillary nerve palsy after arthroscopic shoulder stabilization and to measure the distance between the nerve and capsule in shoulders with a capsular lesion.

Methods: This retrospective study included 2,027 shoulders (1,909 patients; 1,433 male and 476 female patients; mean age, 32 years [age range, 13-81 years]) subjected to arthroscopic soft-tissue stabilization for recurrent shoulder instability from 2005 to 2017. The exclusion criteria were bone grafting or transfer and preoperative axillary nerve symptoms.

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Background: Fatty degeneration of the rotator cuff muscles is reported to be associated with retear after rotator cuff repair. The purpose of this study was to assess the relationship between retear and preoperative fatty degeneration, as quantified by T2 mapping.

Methods: This prospective cohort study included 83 large and 24 massive rotator cuff tears (average age, 67 years; range, 46-82 years).

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Background: Partial articular supraspinatus tendon avulsion (PASTA) lesions are often seen in shoulders of throwing athletes. PASTA lesions in anterior instability are also found in recurrent anterior glenohumeral instability.

Purpose: To investigate the prevalence and location of rotator cuff tears (RCTs), including PASTA lesions, in shoulders with recurrent anterior instability.

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Background: Asians generally have smaller stature than Europeans and Americans, and currently available implants used in reverse shoulder arthroplasty might not fit smaller bony anatomies. However, few articles have reported glenoid geometry in the Asian population. The purpose of this study was to measure the dimensions and orientations of the glenoid from three-dimensional computed tomography reconstructions of elderly Japanese subjects.

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Purpose: This retrospective study aimed to report repair integrity and clinical outcomes after arthroscopic suture bridge subscapularis (SSC) tendon repair.

Methods: The subjects included 101 shoulders subjected to arthroscopic suture bridge repair for full-thickness SSC tear with a minimum of a 2-year follow-up. There were 57 men and 44 women with a mean age of 66 years (range, 32-85 years).

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Background: Capitellar osteochondritis dissecans (OCD) in skeletally immature athletes has often been seen in baseball players and gymnasts. The choice of surgical procedure for unstable lesions in skeletally immature athletes remains controversial.

Purpose: To investigate functional outcomes and radiographic changes in the midterm to long-term postoperative period after arthroscopic (AS) resection for small to large capitellar OCD lesions in skeletally immature athletes.

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The implants used in reverse shoulder arthroplasty were originally designed for white patients; thus, they might not be optimal for smaller Asian patients. The selection of reverse shoulder arthroplasty systems is limited in Japan. The purpose of this study was to measure the geometry of the proximal humerus in elderly Japanese patients to inform implant selection according to humerus size.

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