Investigation of site and frequency of asymptomatic injury in medial structures of the elbow in adolescent baseball players using dedicated magnetic resonance imaging.

PURPOSE: Medial epicondyle (ME) and elbow joint proximal (UCL-p) and distal ulnar collateral ligament (UCL-d) asymptomatic injuries are frequently observed using magnetic resonance imaging (MRI). However, the injury rates vary among these structures in elbow screening of adolescent baseball players, despite being adjacent medial structures of the elbow. This study aimed to retrospectively determine the actual injury site and rate, and investigate the underlying reason for discrepancies anatomically and biomechanically. MATERIALS AND METHODS: Forty-four male adolescent baseball players were scanned using MRI. Two interpreters independently and retrospectively assessed the ME, UCL-p, and UCL-d injuries using the gradient echo axial, sagittal, and coronal planes. RESULTS: The injury prevalence was significantly higher in the ME and UCL-p (> 50% of the participants) than in the UCL-d (22.7%), P < 0.01 and P < 0.01, respectively. Additionally, there was a tendency toward a high-frequency injury rate of the ME or UCL-p. CONCLUSION: The injury site of the medial structures tended to be proximal. The ME and UCL-p were observed to be more frequently injured compared to the UCL-d in adolescent baseball players according to the dedicated MRI findings in this study.

Arthroscopic superior capsule reconstruction with Teflon felt synthetic graft for irreparable massive rotator cuff tears: clinical and radiographic results at minimum 2-year follow-up.

BACKGROUND: Superior capsule reconstruction (SCR) was developed to improve shoulder function and relieve pain in patients with irreparable rotator cuff tears. Here, we investigated the clinical and radiographic outcomes and postoperative complications of SCR using a Teflon graft for reconstruction. METHODS: Thirty-five consecutive patients with irreparable rotator cuff tears underwent SCR with Teflon grafts. The American Shoulder and Elbow Surgeons score, active shoulder elevation, shoulder muscle strength, visual analog scale pain scores, acromiohumeral distance, and postoperative complications were investigated. Data obtained before and after surgery were compared by using a paired t-test, χ2 test, and 1-way analysis of variance, and data from 1-layer-graft SCR (15 patients; mean age, 75.1 years) and 3-layer-graft SCR (20 patients; mean age, 76.6 years) were compared by using an unpaired t-test. The average time to final follow-up was 42 months (range, 24-69 months). RESULTS: SCR using Teflon grafts of either 1 or 3 layers significantly improved the American Shoulder and Elbow Surgeons score (by 20.8, P = .001 for a 1-layer graft; and by 31.1, P < .0001 for a 3-layer graft), visual analog scale score for motion pain (by 3.2, P = .001; and by 3.0, P < .0001), and muscle strength in shoulder abduction (by 11.9 N, P = .02; and by 10.9 N, P = .008). Active elevation at final follow-up was significantly greater in the 3-layer-graft group (142° ± 27°) than in the 1-layer-graft group (107° ± 42°) (P = .006). One year after SCR, acromiohumeral distance in the 3-layer-graft group was significantly greater than preoperatively (P = .04), whereas in the 1-layer-graft group, it was not. On postoperative magnetic resonance imaging, none of the patients in the 3-layer-graft group had graft tears, whereas 2 patients had graft tears and 1 patient had severe synovitis after 1-layer-graft SCR. CONCLUSION: SCR using a Teflon graft-especially a 3-layer graft-significantly improved shoulder function and shoulder abduction strength, with pain relief and a low rate of postoperative complications. SCR using a Teflon graft can be a viable option for irreparable rotator cuff tears, especially when an autograft or allograft is not available.

Closed reduction and minimally invasive surgical treatment of type IIIa fragility fractures of the pelvis associated with ipsilateral periprosthetic femur fracture: A case report.

Patients with fragility fractures of the pelvic ring (FFP) are elderly and, from the perspective of surgical invasion, percutaneous and stable fixation may be a superior surgical method than open reduction and internal fixation (ORIF). While in the case of FFP type IIIa, ORIF, as a rule, typically requires open reduction of the displaced ilium via an anterior intrapelvic approach and/or lateral window of the ilioinguinal approach. We have reported here the case of an 89-year-old woman who suffered from FFP type IIIa with ipsilateral periprosthetic femur fracture that was surgically treated. The iliac fracture was approached in a minimally invasive manner using the traction operation while preparing for femoral shaft fracture surgery, which did not require open reduction, and showed favorable outcomes.

Cable Graft: Simple Superior Capsule Reconstruction Technique for Irreparable Rotator Cuff Tear Using a Teflon Patch.

We describe a simple superior capsule reconstruction technique for irreparable rotator cuff tear using a Teflon patch. In this technique, a triple-folded Teflon patch, suture tape, and a strong suture penetrating through the graft are fixed to the glenoid and greater tuberosity using a suture anchor. This allows for reconstruction of the superior capsule while simultaneously playing a role as a spacer. This procedure's greatest advantage is its simplicity; it is easy to perform, has a short operative time, and avoids the need to collect autologous tissue. More time is saved, as suturing and tying are not required. We believe our study could aid orthopaedic surgeons in clinical decision-making when encountering irreparable rotator cuff repairs.

Angiogenesis and new bone formation in novel unidirectional porous beta-tricalcium phosphate: a histological study.

Affinos® (Kuraray Co., Ltd., Tokyo, Japan) is a beta-tricalcium phosphate (TCP) artificial bone comprising a novel unidirectional porous structure with 57% porosity. This study examined angiogenesis and bone formation over time with unidirectional porous beta-TCP (UDPTCP). Ten Japanese White rabbits were used in this study. A 5 × 8-mm rectangular area of periosteum was resected, followed by preparation of a cortical bone defect using a high-speed bur. UDPTCP was embedded in the defect in the direction of the pores, parallel to the axis of the tibia. Tissue samples were harvested at 2 weeks (n = 3) and 6 weeks (n = 7) after implantation. Just before euthanasia, the vasculature of the lower limb was perfused with saline from the femoral artery and filled with MICROFIL® (Flow Tech, Inc., Carver, MA) to create a vascular cast. The tibia was cut longitudinally at the center of the material. Decalcified sagittal sections treated with hematoxylin and eosin staining, undecalcified sagittal sections treated with Villanueva-Goldner staining, and axial unstained sections were used for histological evaluation. The lengths of the largest vessels and newly formed bone at the material border were measured in a sagittal section. Both lengths were significantly larger at 6 weeks than at 2 weeks. In the axial sections at 2 weeks, newly formed vessels filled with blue dye grew along the pores of the UDPTCP. Mature bone tissue with a lamellar structure was observed at 6 weeks. Our histological findings demonstrated that angiogenesis and bone formation occur over time in UDPTCP.

Change in MRI findings of medial collateral ligament injury in adolescent baseball players with no clinical symptoms over time.

OBJECTIVE: Elbow screening of adolescent baseball players began in 2014 using ultrasound, palpation, and dedicated magnetic resonance imaging (MRI). We frequently encountered subjects showing MCL injury on MRI but no clinical symptoms. We assessed variations in asymptomatic MCL injury findings at follow-up MRI, and clarified the pathogenesis of these findings. MATERIALS AND METHODS: Using a 0.2-T-dedicated MRI, 30 subjects with asymptomatic MCL injury at initial MRI who agreed to follow-up MRI were included. We classified the findings at repeat MRI as follows: (a) disappeared, (b) better, and (c) worse. RESULTS: There were 6, 16, and 8 subjects in groups a, b, and c, respectively. The average age at follow-up was 14.0, 12.1, and 12.4 years in groups a, b, and c, respectively. There were significant differences between groups a and b and between groups a and c. Average height at follow-up of groups a, b, and c was 1.64, 1.52, and 1.57 cm, respectively, with a statistically significant difference between groups a and b. The average size of the short axis of the MCL of subjects in group a was 2.0 cm on the dominant side and 1.5 cm on the contradominant side (P < 0.04). CONCLUSION: Players with asymptomatic MCL injury can continue to play baseball with no limitations, as these findings usually disappear around the age of 14.0 years, when the growth spurt occurs. This finding may be a precursor of 'adaptation', which is generally observed in high school baseball players, suggesting that the MCL adapts as growth occurs.

Supraspinatus muscle location changes after arthroscopic rotator cuff repair: a potential source of preoperatively predicting tear patterns.

PURPOSE: When repairing retracted rotator cuff tears, the tear pattern (eg, crescent-shaped, L-shaped) is best determined intraoperatively by evaluating the mobility of the tendon in multiple directions. The purpose of our study was to evaluate the location of the supraspinatus (SSP) muscle belly on magnetic resonance imaging (MRI) in patients undergoing arthroscopic repair of retracted rotator cuff tears. We hypothesized that the location of the rotator cuff muscle would move after tendon repair, and that the perioperative change in muscle position would correlate with the tear pattern. METHODS: A series of primary arthroscopic repairs for rotator cuff tears with >3 cm of medial retraction from 2015 to 2016 was reviewed. MRIs were performed preoperatively and within 10 days postoperatively. The SSP muscle was assessed on sagittal MRI and evaluated for the "occupation ratio", "tangent sign", and the "location index" proposed in this study. Pre and postoperative MRIs were compared, and correlated with intraoperatively determined tear patterns. Fifty shoulders without rotator cuff pathology were also assessed for the "location index" as control. RESULTS: Fifty-nine shoulders (mean age 65.0 years) were included, among which five reverse L-shaped tears were identified. The occupation ratio and tangent sign improved postoperatively. Preoperatively, in the majority of tears, the SSP muscle was located more posteriorly in the SSP fossa, compared to the control group, and shifted anteriorly after repair. However, in reverse L-shaped tears the SSP muscle was located more centrally in the fossa, and shifted posteriorly following repair. CONCLUSION: Rotator cuff tearing and arthroscopic rotator cuff repair change the location of the SSP muscle. Although repair usually results in shifting of the muscle belly from posterior to anterior, reverse L-shaped tears demonstrated an opposite pattern. The location of the SSP muscle belly may be useful in predicting tear patterns of retracted rotator cuff tears. LEVEL OF EVIDENCE: Level IV (case series).

Bone union of the transferred coracoid graft is the key factor affecting the extent of postoperative graft changes and the clinical results following the modified Bankart and Bristow procedure: a computed tomography scan study.

BACKGROUND: The extent of postoperative changes in the coracoid process grafted during the modified Bankart and Bristow procedure remains unclear. The purpose of the present study was to quantify the postoperative changes in bone surface area as assessed on computed tomography, as well as to clarify the impact of such changes on the clinical results. METHODS: Twenty-three shoulders of 21 subjects who underwent the modified Bankart and Bristow procedure were retrospectively analyzed. Computed tomography images were obtained immediately after surgery and at the final follow-up. The changes in bone surface area of the grafted coracoid process were measured on computed tomography slices in the proximity of the screw bore. Clinical outcomes were evaluated in terms of the Rowe, Walch-Duplay, and simple shoulder test scores. RESULTS: Bone area increased in 15 shoulders (65.2%) and decreased in eight shoulders (34.8%). Bone area increased by 51.3% in shoulders with bone union in the superior part of the coracoid process graft, with no significant differences between the superior and inferior sides of the graft regarding the rate of change in bone surface area (41.4% vs. 68.9% increase). However, in shoulders with bone union in the inferior part of the coracoid process graft, the rate of change in bone area differed significantly between the superior and inferior sides of the graft, exhibiting a 42.3% decrease on the superior side and 39.8% increase on the inferior side. In shoulders with no bone union, bone area decreased by 29.5% (17.4% vs. 39.3% decrease on the superior and inferior side, respectively), whereas the Rowe and Walch-Duplay scores were significantly lower than those noted in shoulders with bone union. CONCLUSIONS: Postoperative bone formation and bone resorption in the coracoid process grafted during the modified Bankart and Bristow procedure depend on whether and where bone union occurs. Graft non-union is associated with inferior clinical results.

Normal imaging laterality on magnetic resonance imaging of the medial epicondyle of the elbow on the dominant side of adolescent male baseball players.

OBJECTIVE: Multimodality elbow screening of adolescent baseball players shows apparent laterality in morphology and signal intensity of the medial epicondyle on dedicated magnetic resonance imaging. We aimed to elucidate actual imaging laterality in the medial epicondyle by comparing magnetic resonance images of the dominant and contradominant elbows and to clarify the clinical meaning and mechanism of this phenomenon. MATERIALS AND METHODS: We used a 0.2-T dedicated magnetic resonance imaging scanner. Eighty adolescent baseball players were enrolled and divided into four age groups: 9-10 years (13 patients); 11 years (28 patients); 12 years (24 patients) and 13-14 years (15 patients). The long and short axes of the ossification center and distance of the epiphyseal plate and the cartilage of the lower pole of the medial epicondyle were measured. Signal intensity of the ossification center was visually evaluated. RESULTS: Owing to their age, ossification and cartilage size on the dominant side were significantly larger in all boys (P < 0.01). All age groups had larger ossification and cartilage in the dominant elbow (P < 0.01). Ossification showed an apparent lower signal intensity on the dominant side (P < 0.01). CONCLUSIONS: Larger ossification and cartilage size of the medial epicondyle in the dominant elbow suggested that the medial collateral ligament to the medial epicondyle induces excessive repetitive tensile stress, but without clinical symptoms. Functional or microanatomical damage of the medial epicondyle may induce a lower ossification signal in the dominant elbow, thereby decreasing fatty bone marrow and inducing sclerotic changes.

Formation of osteon-like structures in unidirectional porous hydroxyapatite substitute.

Unidirectional porous hydroxyapatite (UDPHAp) bone substitute comprises a microstructure of cross-sectionally oval pores with diameters ranging from 30 to 300 µm. Bone remodeling within the UDPHAp is expected upon implantation into bone; however, the mechanism and factors influencing this bone growth remain unclear. The objectives of the present study were to assess the vasculature and microstructure of newly formed bone and to determine how bone formation is affected by load transfer and UDPHAp pore size. Formation of osteon-like structures, defined by the presence of lacunae, canaliculi and a central lumen containing capillaries, was observed within the implanted UDPHAp material in all animals after six weeks. The number of osteocytes and osteon-like structures in areas adjacent to the cortex of recipient bone was significantly higher than in areas next to the medullary cavity throughout the recovery period. Notably, osteon-like structures tended to form in smaller diameter pores. Continuous bone remodeling might be promoted by the rapid formation of unidirectional capillaries and the osteocyte lacunae-canalicular system. Load transfer and smaller pore size could positively affect cortical bone regeneration. © 2018 The Authors Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2665-2672, 2018.

Shoulder motion assistance using a single-joint Hybrid Assistive Limb® robot: Evaluation of its safety and validity in healthy adults.

PURPOSES: To evaluate the feasibility of using the single-joint Hybrid Assistive Limb® robot (HAL) to assist with shoulder flexion-extension in healthy adults, and to assess the capacity of the HAL to analyze the bioelectrical signals of muscle activity for shoulder flexion-extension. METHODS: This cross-sectional feasibility study included six healthy adult men with no impairment in shoulder motion. The single-joint HAL was fixed to a custom-designed platform and upper arm attachment, and aligned 3 cm below the acromion process. Vital signs, shoulder fatigue, and shoulder pain were evaluated before and after the shoulder elevation exercise performed with and without the HAL. Activity of selected muscles of the shoulder was recorded using a wireless superficial electromyography device. Shoulder movement was captured using a three-dimensional motion analysis system. RESULTS: The HAL supported smooth flexion-extension of the arm at the shoulder joint, with no negative effects on vital signs, shoulder fatigue, and shoulder pain. The HAL decreased muscle activity levels, with a 55% decrease in trapezius muscle activity. The upward rotation angle of the scapula was significantly lower with the HAL at 120° of shoulder flexion. CONCLUSION: The single-joint HAL provided safe and effective assistance to scapular plane shoulder flexion-extension among healthy adults.

Autologous Concentrated Bone Marrow Grafting for the Treatment of Osteonecrosis of the Humeral Head: A Report of Five Shoulders in Four Cases.

Five shoulders in four patients affected by advanced osteonecrosis of the humeral head were treated with autologous concentrated bone marrow grafting. Bone marrow sample was aspirated from the iliac crests, concentrated by a centrifugation technique, and injected into the necrotic site. The shoulders were evaluated radiologically with X-ray scoring and clinically with measurement of range of motion and pain score (visual analogue scale, VAS). The mean follow-up period was 49.4 (range, 24-73) months. The concentration ratio of nucleated cells was calculated and the number of transplanted mesenchymal stem cells (MSC) was estimated by a colony-forming assay. All four shoulders with stage 3 disease achieved joint sparing. One shoulder with stage 4 disease required replacement surgery. Clinical evaluation of the spared joints showed improvement in range of motion in two cases and deterioration in two cases. VAS scores were 0 after surgery in three cases. The mean concentration ratio was 2.73, and the mean number of transplanted MSC was 1125. The outcomes of autologous concentrated bone marrow grafting for advanced osteonecrosis of the humeral head were varied. Further research is needed to determine the effectiveness and the indications of the present surgery.

Clinical interpretation of asymptomatic medial collateral ligament injury observed on magnetic resonance imaging in adolescent baseball players.

PURPOSE: Magnetic resonance imaging (MRI) of medial collateral ligament (MCL) injury of the elbow was often observed in asymptomatic adolescent baseball players. We aimed to clarify the clinical interpretation of "asymptomatic MCL injury observed on MRI" by comparing MRI, ultrasonography (US), and physical findings. MATERIALS AND METHODS: Sixty-four asymptomatic adolescent baseball players (mean 11.2 years) were enrolled. An open-type 0.2T MRI was used. MCL function was evaluated by measuring the opening of the ulnohumeral joint using US. Physical findings included MCL tenderness, the moving valgus test, and the Milking test. The correlation between MRI and US, and MRI and physical findings were analyzed. RESULTS: Thirty-four subjects (53.1%) showed MCL injury by MRI. The mean laterality of the ulnohumeral joint opening showed no significant difference (P = 0.16) between the group with (0.29 ± 1.06 mm) and without (0.08 ± 0.96 mm) MCL injury on MRI. There was no correlation between MRI and physical findings except for a weak correlation between subjects with positive Milking test and MCL injury on MRI (φ coefficient = 0.3, P = 0.02). CONCLUSION: 'Asymptomatic MCL injury on MRI' had little correlation to ligament dysfunction. It might represent the transition period to MCL thickening called "adaptation."

Feasibility and Efficacy of Autologous Bone Marrow Aspirate Transplantation Combined with Human Parathyroid Hormone 1-34 Administration to Treat Osteonecrosis in a Rabbit Model.

No studies have examined the transplantation of a bone marrow aspirate (BMA) containing mesenchymal stem cells (MSCs) combined with human parathyroid hormone 1-34 (hPTH1-34) administration. Therefore, we evaluated the feasibility and efficacy of autologous BMA transplantation combined with hPHT1-34 administration in a bone necrosis model. The metatarsal bones of rabbits were necrotized using liquid nitrogen, and the rabbits received a BMA transplantation or saline injection followed by hPTH1-34 (30 µg/kg) or saline administration three times per week (n = 3-4 per group). The rabbits were euthanized at 12 weeks after the initiation of treatment. No systemic adverse effects or local neoplastic lesions were observed. Importantly, the rabbits in the BMA transplantation plus hPTH1-34 group showed the highest bone volumes and histological scores of new bone. These data confirmed the feasibility of BMA transplantation combined with hPTH1-34, at least during the experimental period. The observed efficacy may be explained by a synergistic effect from the stimulation of MSC differentiation to osteoblasts with hPTH1-34-mediated suppression of apoptosis in osteoblasts. These results indicate the promising potential for BMA transplantation combined with hPTH1-34 administration in bone necrosis treatment. Longer term experiments are needed to confirm the safety of this therapeutic strategy.

Nontraumatic central fracture dislocation of the hip in a patient with chronic kidney disease and post gastrectomy.

OBJECTIVE: PATIENTs with secondary hyperparathyroidism caused by chronic kidney disease (CKD) develop secondary osteoporosis, which increases fracture risk. We report a case of insufficiency fractures complicated by secondary osteoporosis caused by chronic renal failure and gastrectomy. PATIENT: A 78-year-old man with a medical history of nephrotic syndrome and gastric cancer experienced an occult intertrochanteric fracture of his left femur after falling. RESULTS: Ten days after the first fracture, the patient was treated with hemodialysis for acute uremic symptoms. Eight weeks after this fracture, he sustained a right insufficiency acetabular fracture and was treated with total hip arthroplasty (THA). CONCLUSION: For patients with CKD, effective fracture prevention is difficult. THA with reconstruction of the acetabulum was an effective therapy in a patient with nontraumatic central fracture dislocation of the hip.

Bone Regeneration and Remodeling within a Unidirectional Porous Hydroxyapatite Bone Substitute at a Cortical Bone Defect Site: Histological Analysis at One and Two Years after Implantation.

Unidirectional porous hydroxyapatite (UDPHAp) is an artificial bone substitute with a unique microstructure consisting of 100-300-µm oval pores that present the material unidirectionally. UDPHAp has a compression strength of 14 MPa and a porosity of 75%, which promotes cell migration and capillary formation within the material. Despite these advantageous properties, bone remodeling and bone formation with UDPHAp remain unclear. To examine long-term remodeling and differences in bone formation based on the defect site, trapezoidal prism-shaped UDPHAp blocks were implanted into rectangular-shaped cortical bone defects in the proximal tibia of Japanese white rabbits. Histological analysis performed at 52 and 104 weeks after implantation revealed that bone and capillaries had formed within the implanted UDPHAp material. Bone formed within the UDPHAp implanted in the cortical defect of rabbit tibia and remodel up to two years. The percentage of new bone area within UDPHAp was larger in cortical lesions than that in medullary lesions. These findings suggest that UDPHAp is a promising material for the repair of non-critical-sized cortical bone defects.