Periprosthetic Joint Infection Following Reverse Shoulder Arthroplasty Treated With Continuous Local Antibiotic Perfusion: A Case Report.

Prosthetic joint infection (PJI) is a crucial complication of reverse shoulder arthroplasty (RSA). Continuous local antibiotic perfusion (CLAP) with a high-concentration antimicrobial pharmacy administration method has recently received attention owing to its effectiveness in the treatment of bone and soft tissue infections. We herein report a case of PJI following RSA that was successfully treated with CLAP without removal of the entire implant. A 73-year-old woman with comorbidities of diabetes mellitus and hypertension underwent RSA. The wound was found to be swollen eight weeks after RSA, and purulent content that was positive for Propionibacterium granulosum was identified. Blood samples indicated a mildly elevated inflammatory response. With a diagnosis of PJI spread from the intra-articular to subcutaneous regions without implant loosening, the patient underwent surgical treatment nine weeks after RSA. The contaminated tissues were thoroughly debrided, and the prosthetic joint was preserved by replacing the glenosphere and polyethylene liner. Intra-soft tissue antibiotic perfusion (iSAP) tubes and effluent drains were placed intra-articularly and subcutaneously, and gentamicin was infused continuously for 12 days. In addition, ceftriaxone and rifampicin were administered. The patient was subsequently treated with minocycline and sulfamethoxazole/trimethoprim or clindamycin for eight weeks. The inflammatory reaction became negative six weeks postoperatively, and the patient had no recurrence at 15 months postoperatively. Treatment of PJI is considered a long-lasting, challenging process. This case report supports the feasibility of using CLAP in the treatment of PJI.

A survey and biomechanical analysis of the feasibility of the thumb test for determining the cancellous bone quality for stemless shoulder prosthesis.

BACKGROUND: The effect of the thumb test for assessing the cancellous bone quality at the resection plane of the proximal humerus on determining the application of a stemless shoulder prosthesis remains unclear. This study was conducted to survey the current utilization of the thumb test among surgeons and to investigate biomechanical features of the thumb test. METHOD: A survey among shoulder surgeons who had experience with stemless prostheses was conducted to investigate the current utilization of preoperative assessments and intraoperative thumb test when applying stemless prosthesis. Biomechanical experiments for the thumb test using artificial bone models were performed to assess the compression force, contact pressure and area. According to the preliminary survey, three compression techniques were assessed: compression perpendicular to the surface with thumb pad (P-pad technique) or tip of the thumb (P-tip technique), or compression in the vertical direction simulating compression along the longitudinal axis of the humeral shaft with tip-pad of the thumb (H-axis technique). The contact area was separated into three subregions (proximal, middle and distal) to assess the distribution of contact pressure. RESULTS: Among 38 surgeons, 66% utilized the thumb test intraoperatively. The P-pad technique was more frequently applied than the P-tip or H-axis techniques (80%, 4% and 16%, respectively). Although with wide variation among the examiners, biomechanical assessments revealed the P-pad technique showed larger contact area and less compression force than the P-tip technique. The P-pad technique provided no significant localized differences in the mean contact pressure on the compressed plane, whereas the P-tip and H-axis techniques showed significant differences among subregions. CONCLUSION: This survey demonstrated relatively frequent application of the thumb test on applying the stemless shoulder prosthesis. Biomechanical assessment revealed the thumb test can hinder objective reproducibility among examiners; therefore, further investigations to identify feasible assessments of the bone quality is required.

The quantification of muscle activities during arm elevation following reverse shoulder arthroplasty or superior capsular reconstruction for irreparable rotator cuff tears using positron emission tomography.

BACKGROUND: Reverse shoulder arthroplasty (RSA) and superior capsular reconstruction (SCR) are recognized as surgical options for an irreparable rotator cuff tear. However, the postoperative changes of the muscle activity patterns remain unclear. The purpose of this study was to investigate the quantified muscle activities on shoulder elevation in patients treated with RSA or SCR using fluorine-18-labelled fluorodeoxyglucose-positron emission tomography. METHODS: Asymptomatic shoulders that underwent RSA or SCR and those without a rotator cuff tear were analyzed as the RSA, SCR, and control groups. All subjects underwent shoulder elevation exercise, followed by a fluorine-18-labelled fluorodeoxyglucose-positron emission tomography examination. Using previously established methods to quantify the uptake of each muscle on positron emission tomography images, the standard uptake values (SUVs) for 16 portions of the deltoid, rotator cuff, and periscapular muscles were obtained to compare the muscle activity patterns among 3 groups. RESULTS: The deltoid muscle showed the most characteristic differences according to the surgeries. The mean SUVs of the anterior, middle, and posterior deltoid were 3.3, 3.7, and 1.5 for the RSA group; 2.7, 4.2, and 1.5 for the SCR group; and 1.3, 2.0, and 0.9 for the control group, respectively. In comparison to the control group, both the RSA and SCR groups showed significantly increased SUVs at all portions of the deltoid muscle. The RSA group showed similar SUVs for the anterior and middle deltoid, whereas the SCR and control groups showed greatest SUVs at the middle deltoid. In addition, the serratus anterior, levator scapulae, and upper portion of the trapezius in the RSA group showed greater SUVs than in the control group. CONCLUSION: The deltoid muscle showed increased activity in the RSA and SCR groups. The middle deltoid was mainly used in the SCR group, whereas the anterior and middle deltoid, as well as the upward rotator muscles of the scapula, were mainly used in the RSA group.

Simultaneous Reverse Shoulder Arthroplasty and Open Reduction With Internal Fixation for Bilateral Proximal Humerus Fractures in the Elderly: A Report of Two Cases.

Simultaneous bilateral proximal humerus fractures (PHFs) caused by a single trauma are considered rare. We herein report two patients with bilateral PHFs treated based on our treatment strategy: reverse shoulder arthroplasty (RSA) to obtain rigid stability for one shoulder and open reduction with internal fixation (ORIF) to regain the mobility of external and internal rotation for the other. By using Neer's four-segment fracture classification, patients underwent RSA for one shoulder with the more advanced fracture type and ORIF for the other. In Case 1, a 74-year-old female presented with bilaterally comminuted PHFs and underwent surgical treatment with RSA and ORIF. In Case 2, a 78-year-old female with the comorbidity of rheumatoid arthritis and a history of total elbow arthroplasty for both elbows had bilateral PHFs and underwent surgical treatment with RSA and ORIF. Postoperatively, both patients were instructed to perform exercises including passive range of motion (ROM) for a week, active ROM exercises for two weeks, and muscle strengthening for six weeks after the surgery. At the follow-up, both patients were satisfied with the pain relief and functional recovery. Especially, increased ROM for external and internal rotation was obtained in shoulders with ORIF. These case reports describe a viable treatment option comprising simultaneous RSA and ORIF, and this surgical approach may restore shoulder functions in cases of bilateral PHFs.

Three-dimensional quantitative measurements of atrophy and fat infiltration in sub-regions of the supraspinatus muscle show heterogeneous distributions: a cadaveric study.

INTRODUCTION: Rotator cuff tears are common in the older population. Atrophy and fat infiltration develop un-evenly in torn supraspinatus (SSP) muscles leading to pre- and post-surgical complications. The purpose of the current study was twofold: first, to implement a volumetric and quantitative magnetic resonance imaging (MRI) approach to quantify the degree of muscle atrophy and fat infiltration within the SSP muscle and its four sub-regions (AS, PS, AD, and PD); second to compare 3-D MRI outcomes to the standard 2-D assessment and investigate their relationship with tear size. MATERIALS AND METHODS: Fifteen cadaveric shoulders were obtained and MRI performed. Quantitative 3-D outcomes included SSP muscle volume, fossa volume, fat-free muscle volume, and fat fraction for the whole SSP muscle and its four sub-regions. 2-D and qualitative measurements included tear size, 2-D fat infiltration using the Goutallier classification, tangent sign, and occupation ratio. RESULTS: Linear regression outcomes with tear size were not significant for both cross-sectional area (r = - 0.494, p = 0.061) and occupation ratio (r = - 0.011, p = 0.969). Tear size negatively correlated with fat-free muscle volume for both AS and PS sub-regions (AS: r = - 0.78, p < 0.001; PS: r = - 0.68, p = 0.005, respectively) while showing no significant correlation with fat fraction outcomes. AD and PD sub-regions positively correlated with tear size and fat fraction outcomes (AD: r = 0.70, p = 0.017; PD: r = 0.52, p = 0.045, respectively), while no significant correlation was observed between tear size and fat-free muscle volumes. CONCLUSION: Quantitative 3-D volumetric assessment of muscle degeneration resulted in better outcomes compared to the standard 2-D evaluation. The superficial supraspinatus muscle sub-regions primarily presented muscle atrophy, while the deep sub-regions were mainly affected by fat infiltration. 3-D assessments could be used pre-surgically to determine the best course of treatment and to estimate the muscles' regenerative capacity and function.

Surgical treatment for persistent second carpometacarpal joint pain.

The purposes of this study were to demonstrate the clinical characteristics of patients with persistent second carpometacarpal (CMC) joint pain without bony abnormalities known as the carpal boss, and to assess the clinical efficacy of surgical stabilization of the second CMC joint. Eleven patients had persistent wrist pain with characteristic symptoms, including tenderness over the second CMC joint, increased symptoms when the involved hand was placed on the ground or gripped strongly with the involved hand, a positive metacarpal stress test and temporary pain relief with the intra-articular injection of the lidocaine. The patients underwent arthrodesis of the second CMC joint. All cases showed radiologically confirmed fusion of the second CMC joint. At the final followup examination, 10 of 11 patients resulted in satisfactory clinical outcomes, excepting one patient with remnant pain and restricted range of wrist motions. This report highlights the importance of conducting a careful assessment of patients who present with persistent second CMC joint pain without the bony abnormalities, such as carpal bossing. Surgery to stabilize the second CMC joint may be an option to improve their symptoms when conservative treatment fails.

Ultrasonographic Measurement of the Median Nerve Transverse Diameter at the Wrist for Diagnosing Carpal Tunnel Syndrome.

Background: Ultrasonographically measuring the median nerve cross-sectional area (MN-CSA) is a useful and complementary method for diagnosing carpal tunnel syndrome (CTS). This study investigated the usefulness of the median nerve transverse diameter (MN-TD) as a simpler and easier technique than MN-CSA for diagnosing CTS severity. Methods: We examined 145 hands from 101 patients with CTS and 114 age- and gender-matched control hands. Based on the electrodiagnostic findings, the severity of CTS was divided into minimal, mild, moderate, severe and extreme. An ultrasonographic assessment of MN-TD and MN-CSA was performed to measure the maximal values around the carpal tunnel inlet level. The values were assessed for comparisons between the CTS and control groups and for the evaluation of differences by CTS severity. Results: The ultrasonographic measurements of MN-TD and MN-CSA were significantly increased in the CTS group compared to the normal group. Furthermore, both measurements significantly increased with increasing CTS severity. A receiver operating characteristic curve (ROC) analysis showed that participants with MN-TD > 7.2 mm had CTS with 88% specificity and 74% sensitivity, and those with MN-CSA > 12.0 mm2 had CTS with 86% specificity and 84% sensitivity. Conclusions: Ultrasonographic measurement for MN-TD may be useful for diagnosing CTS patients and predicting the severity.

Clinical Features of Ulnar Tunnel Syndrome and the Diagnostic Value of Nerve Conduction Measurements.

OBJECTIVES: The purposes of this study were to assess the clinical features of ulnar tunnel syndrome (UTS) and to investigate the diagnostic value of nerve conduction measurements for UTS. METHODS: Eighteen patients with UTS were reviewed retrospectively. Fifteen patients had intrinsic muscle atrophy and motor weakness, and 15 had numbness with hypesthesia. The compound muscle action potentials (CMAPs) from the first dorsal interosseous (FDI) muscle and the abductor digiti minimi (ADM) muscle and the sensory nerve action potential (SNAP) from the little finger were recorded and analyzed. All patients underwent ulnar tunnel release surgery and neurolysis. Static two-point discrimination test results and pinch strengths were assessed before and after surgery. RESULTS: Before surgery, FDI-CMAP was recorded in 17 patients, and ADM-CMAP in 16, and all showed delayed latency and/or low amplitude. SNAP was recorded in eight patients and two showed delayed latency. The causes of ulnar nerve lesions were ganglion in five patients, traumatic adhesion in four, ulnar artery aberrancy in four, pisohamate arch in three, anomalous muscle in one, and ulnar vein varix in one. The sites of the lesions were in zone 1 of the ulnar tunnel anatomy in 12 patients, in zone 2 in 2, and in zones 1 and 2 in 4. After surgery, all patients obtained recovery of motor function and sensation; however, postoperative FDI-CMAP and ADM-CMAP did not improve to the normal range. CONCLUSIONS: The causes of UTS were ganglion, traumatic adhesion, ulnar artery aberrancy, and pisohamate arch. Both FDI-CMAP and ADM-CMAP were valuable for electrophysiological diagnosis of UTS.

Does glenoid remodeling occur with an erosion-type bone loss after arthroscopic Bankart repair?

INTRODUCTION: Fragment-type glenoid bone loss is known to remodel after arthroscopic Bankart repair. To our knowledge, no studies have been reported about the morphologic changes of the erosion-type bone loss. AIM: To determine the morphologic changes of erosion-type glenoid bone loss after arthroscopic Bankart repair. METHODS: Twenty-eight patients (mean age: 31 years) with traumatic anterior glenohumeral instability with an erosion-type glenoid bone loss <25% underwent arthroscopic Bankart repair. The minimum follow-up was 2 years. Pre- and postoperative bilateral computed tomography scans were performed in all patients. The width and surface area of the glenoid were measured by a software program and compared pre- and postoperatively. RESULTS: The recurrence rate was 7.1% (2 of 28 shoulders). The size of the bone loss was 7.2% ± 5.3% (mean ± standard deviation). The preoperative glenoid width and area were 24.9 ± 2.2 mm and 7.0 ± 0.8 cm2, respectively, and the postoperative ones (2 years after surgery) were 24.7 ± 2.2 mm and 6.8 ± 0.8 cm2, respectively. There were no significant differences between the pre- and postoperative glenoid width and area. DISCUSSION AND CONCLUSION: Unlike the fragment-type bone loss, the erosion-type bone loss <25% did not show any morphologic changes of the glenoid at least 2 years after arthroscopic Bankart repair.

Mechanism and patterns of bone loss in patients with anterior shoulder dislocation.

BACKGROUND: Bony defects are common injuries associated with anterior shoulder dislocation. It is generally thought that these bony defects are created at the time of dislocation. However, there have been no biomechanical reports demonstrating the exact time point when these lesions occur. The purpose of this study was to clarify when, how, and which types of bony defects were created during experimental dislocation in cadaveric shoulders. METHODS: Fifteen fresh-frozen cadaveric shoulders (mean age at the time of death, 79 years) were fixed in a custom testing machine. First, the glenohumeral joint was inspected by arthroscopy. Then, the arm was held at 60° of abduction and maximum external rotation and was manually extended horizontally under fluoroscopy until an anterior dislocation occurred. Next, a force of 800 N was applied to a Kirschner wire inserted in the humeral head in the direction of the pectoralis major with use of an air cylinder. We waited until the arm came to equilibrium under this condition. Finally, the glenohumeral joint was arthroscopically examined. We further performed x-ray micro-computed tomography and histologic examination in 1 shoulder with a bipolar lesion. RESULTS: After the anterior dislocation, a Bankart lesion was created in 9 of 15 shoulders and a fragment-type glenoid defect (avulsion fracture) was created in 4. A Hill-Sachs lesion, on the other hand, was not observed after the dislocation. The equilibrium arm position was 40° ± 17° in flexion, 45° ± 22° in abduction, and 27° ± 19° in external rotation. In this arm position, newly created lesions were Hill-Sachs lesions in 6 shoulders and erosion-type glenoid defects (compression fracture) in 7. Micro-computed tomography, performed in a single specimen, showed a flattened anterior glenoid rim with collapse of trabecular bone. Histologic analysis of nondecalcified sections using hematoxylin-eosin staining indicated that the anterior rim of the glenoid was compressed and flattened. The cortex of the anterior glenoid rim could be clearly observed. CONCLUSION: The fragment-type glenoid defect (avulsion fracture) was observed at the time of dislocation, whereas the erosion-type defect (compression fracture) was observed when the arm came to equilibrium in the midrange of motion. Hill-Sachs lesions were created not at the time of dislocation but after the arm came to equilibrium.

Shoulder arthroplasty in patients with immunosuppression following solid organ transplantation.

BACKGROUND: The purpose was to determine the risk and outcomes of primary shoulder arthroplasties in patients with immunosuppression who had undergone solid organ transplantation. METHODS: Using a single institution's total joint registry, we reviewed 30 primary shoulder arthroplasties in 25 post-transplantation patients, including 12 total shoulder arthroplasties, 10 hemiarthroplasties, and 8 reverse shoulder arthroplasties, between 1985 and 2012. Therapy and patient variables were recorded, including immunosuppressive therapy protocols, the date of preceding solid organ transplantation, and specific medications taken in the perioperative period. We matched a cohort of control patients for age, sex, type of implant, and year of surgery at a ratio of 4:1. Two groups were compared regarding mortality risk, complications, and clinical outcomes (pain score, range of motion, and American Shoulder and Elbow Surgeons score). RESULTS: No periprosthetic infections occurred in the post-transplantation group at a mean follow-up of 39 months. However, the post-transplantation group showed an increased risk of periprosthetic fractures compared with the control group (hazard ratio, 8.18; 95% confidence interval, 1.22-70.98; P = .03). Despite the increase in fractures, the overall number of complications did not differ between the groups. Furthermore, postoperative shoulder function and outcome scores were not significantly different between patients who had a prior transplant and those who did not. CONCLUSION: Primary shoulder arthroplasty in patients with immunosuppression who underwent solid organ transplantation is a successful procedure to treat glenohumeral arthritis. In contrast, there may be an increased risk of periprosthetic fractures in patients with a history of a solid organ transplant.

Comparison of best-fit circle versus contralateral comparison methods to quantify glenoid bone defect.

BACKGROUND: Several measurement techniques have been reported to quantify glenoid bone defect in patients with anterior shoulder instability. Among them, the method that uses a best-fit circle and another that uses the contralateral glenoid as a control are most commonly used. However, to our knowledge, no study has been reported that compared the reliability of these methods. The purpose of this study, therefore, was to determine which of these methods has higher reproducibility. METHOD: In this study, 3-dimensional computed tomography data from 94 patients (mean age 29 years) with unilateral anterior shoulder instability were used. Three examiners measured the glenoid bone defect of each patient 3 times using 2 techniques: the best-fit circle method and the contralateral comparison method. Intra- and interobserver reliabilities were measured using intraclass correlation coefficient (ICC). RESULTS: The intraobserver reliability was found to be 0.91 for the best-fit circle method and 0.98 for the contralateral comparison method. The interobserver reliability was 0.77 for the best-fit circle method and 0.88 for the contralateral method. The percentage of glenoid defect was 11.5% when using the best-fit circle and 10.7% with the contralateral method. CONCLUSION: The contralateral comparison method was more reliable than the best-fit circle method for quantifying the amount of glenoid bone loss.

Peripheral-Track and Central-Track Hill-Sachs Lesions: A New Concept of Assessing an On-Track Lesion.

BACKGROUND: It has been demonstrated biomechanically that 25% is a critical size defect of the glenoid. However, a recent clinical study reported that a bone loss between 13.5% and 20% (subcritical bone loss) led to impairment of quality of life but not a recurrence of instability. PURPOSE: To clarify whether a subcritical bone loss exists in assessing a Hill-Sachs lesion via a disease-specific quality of life questionnaire. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Fifty patients (mean age, 27 years) with <25% glenoid defect who were treated with arthroscopic Bankart repair for recurrent anterior dislocation were assessed at a mean follow-up of 28 months. All had an on-track Hill-Sachs lesion. The Western Ontario Shoulder Instability Index (WOSI) and Rowe scores were used for the clinical evaluation. The Hill-Sachs interval was measured on 3-dimensional computed tomography images and divided by the glenoid track width, defined as the Hill-Sachs occupancy (in percentages). The glenoid track was divided into 4 zones based on the percentage of the Hill-Sachs occupancy: zone 1, <25%; zone 2, 25% to <50%; zone 3, 50% to <75%; and zone 4, ≥75%. RESULTS: The recurrence rate was 6% (3 of 50 shoulders). The Rowe score significantly improved from 45.2 ± 4.7 (mean ± SD) preoperatively to 92.3 ± 6.5 at the final follow-up (P < .05). The WOSI score also significantly increased from 46.6% ± 19.3% preoperatively to 72.3% ± 21.0% at the final follow-up (P < .001). The WOSI score of patients in zone 4 (peripheral-track lesion) (n = 10) was significantly lower than those in the other zones (central-track lesion) (P = .0379). Of the 10 patients with the peripheral-track lesion, 5 had a <40% WOSI score, similar to the preoperative WOSI score (46.6%). CONCLUSION: Patients with on-track lesions can be divided into 2 subgroups: those with the Hill-Sachs occupancy ≥75% (peripheral-track lesion) showed significantly worse WOSI score without recurrent instability events than those with the Hill-Sacks occupancy <75% (central-track lesion).

Effect of subcritical glenoid bone loss on activities of daily living in patients with anterior shoulder instability.

BACKGROUND: It has been biomechanically demonstrated that 20% to 25% is a critical glenoid bone loss. Recently, there are several reports describing that a bone loss less than 20% to 25% needed to be treated because patients may have decreased quality of life without recurrent instability events. The purpose of this study was to clarify the presence of subcritical bone loss that would affect postoperative instability or quality of life. METHODS: Subjects were 43 patients aged≤40years with less than 25% glenoid bone loss who had undergone arthroscopic Bankart repair. These patients were assessed at a mean follow-up of 32months. The Western Ontario Shoulder Instability (WOSI) and Rowe scores were used for the clinical evaluation. Patients were divided in 3 groups based on the percentage of bone loss: group 1: <8%; group 2: 8% to 17%; and group 3: >17%. RESULTS: The recurrence rate was 7% (3/43 shoulders). A weak negative correlation was seen between bone loss and sports/recreation/work domain of the WOSI score (r=-0.304, p=0.0191). The WOSI for group 3 was significantly lower than that for group 1 and 2 (p=0.0009). The male WOSI scores were significantly lower than the female ones (p=0.0471). The WOSI scores of the contact athletes were significantly lower than those of non-contact athletes (p=0.0275). All the patients in Group 3 were males and participated in contact sports. CONCLUSION: Glenoid bone loss between 17% and 25% is considered to be a "subcritical bone loss" in our series, especially in male patients who are involved in sports or high-level activities. LEVEL OF EVIDENCE: III, retrospective study.

Curved-guide system is useful in achieving optimized trajectory for the most inferior suture anchor during arthroscopic Bankart repair.

BACKGROUND: A curved-drill guide system was recently introduced to achieve a better trajectory for a low anteroinferior anchor during arthroscopic Bankart repair. However, the clinical performance of such a device remains unclear. The purpose of this study was to evaluate the trajectory and position of the low anteroinferior suture anchor with use of the curved-guide system in clinical cases. METHODS: We enrolled 41 cases of arthroscopic Bankart repair in this study. Of these cases, 9 were repaired using the curved drill guide whereas 32 were repaired using a conventional straight guide. Postoperative computed tomography scans were obtained, and 3-dimensional models of the scapula were reconstructed. Notable perforations of the opposite cortex by the most inferior anchors were recorded. The clock-face angle, insertion angle, and insertion distance were measured. RESULTS: The anchor perforation rate in the curved-guide group (11%) was significantly lower than that in the straight-guide group (56%) (P = .02). The insertion distance in the curved-guide group was significantly shorter than that in the straight-guide group (4.0 ± 1.6 mm vs. 7.0 ± 2.4 mm, P < .01). The clock-face angle and insertion angle were significantly greater in the perforated straight-guide group than in the nonperforated groups. The percentage of anchors in the absolute safe zone (clock-face angle > 135° and < 165° and insertion angle < 100°), where no anchors perforated, was greater in the curved-guide group than the straight-guide group. CONCLUSION: Compared with the conventional straight guide, the curved-guide system provides better placement of the most inferior suture anchor during arthroscopic Bankart repair.

Fatty degeneration and wnt10b expression in the supraspinatus muscle after surgical repair of torn rotator cuff tendon.

PURPOSE: In the torn rotator cuff muscles, decreased expression of wnt10b prior to elevation of peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα) has previously been reported. The purpose of this study is to elucidate the expression profiles of these adipogenesis-related genes after rotator cuff detachment and reattachment in a rabbit model. METHODS: We investigated gene expression profiles of PPARγ, C/EBPα, and wnt10b in different parts of rabbit supraspinatus (SSP) muscle after tendon detachment (n = 6 for each time point). In addition, we assessed expression of the same genes after SSP reattachment with different intervals from initial detachment (n = 6). Fatty degeneration of the SSP muscle was examined by Oil red-O staining. Gene expression profiles were examined by quantitative real-time polymerase chain reaction. RESULTS: After SSP detachment, Oil red-O-positive oil deposits increased after 3 weeks. In the SSP reattachment model, numerous Oil red-O-positive cells were present at 5-week reattachment, following 2- and 3-week detachment. PPARγ and C/EBPα messenger ribonucleic acid expression exhibited a significant increase at 2 and 3 weeks after SSP detachment and remained increased at 5-week reattachment after 2- and 3-week detachment. A decreased expression of wnt10b was observed from 1 week after SSP detachment. Expression of wnt10b was recovered not in the central area of the SSP muscle but in the periphery after reattachment. Adipogenic change was not observed when SSP tendon was reattached after 1-week detachment. CONCLUSIONS: These results may suggest that once the adipogenic transcription factors, PPARγ and C/EBPα, were elevated, repair surgery after rotator cuff tear could not prevent the emergence of fat in the SSP muscle.

Surgical decision making based on the on-track/off-track concept for anterior shoulder instability: a case-control study.

BACKGROUND: The purpose of this study was to assess the clinical outcomes of patients with anterior shoulder instability who underwent surgical treatment according to the on-track/off-track concept. METHODS: We retrospectively analyzed patients who underwent surgical treatment according to the glenoid track concept with a minimum of 2 years' follow-up. By use of preoperative 3-dimensional computed tomography images, surgical options were selected: arthroscopic Bankart repair (ABR) for patients with on-track lesions and the Latarjet procedure or ABR with the remplissage procedure for patients with off-track lesions. The recurrence rate was assessed at 2-year follow-up after surgery. RESULTS: Among 92 patients enrolled in this study, 81 had on-track lesions and underwent ABR. Of the 11 patients with off-track lesions, 1 underwent ABR with the remplissage procedure and 10 underwent the Latarjet procedure. Recurrences occurred in 4 patients treated by ABR (5%), whereas no recurrences were observed in off-track cases treated by the remplissage or Latarjet procedure. CONCLUSION: Clinical application of the on-track/off-track concept for determining surgical options in preoperative planning seems to be useful to prevent recurrent instability after surgery.

Arthroscopic Excision of Intra-Articular Osteoid Osteoma at the Elbow.

Osteoid osteoma (OO) apparent in the intra-articular region of the elbow is very rare. Although computed tomography-guided excision and radiofrequency ablation have been recognized as useful treatment options, arthroscopic excision has recently received focus as an alternative strategy for lesions close to neurovascular structures or intra- and juxta-articular lesions. We herein report a 17-year-old female who underwent arthroscopic treatment for intra-articular OO located at the olecranon/coronoid fossa. Her symptoms included elbow pain that was exacerbated at night and contracture of elbow flexion-extension, and she was diagnosed with intra-articular OO after 12 months of symptomatic history. Arthroscopically, thorough synovectomy for both the anterior and posterior aspects of the joint enabled definition of the tumor margin with hyperemic alteration and excision of the lesion as an en bloc specimen. At the 12-month follow-up, the patient had no recurrence of elbow limitation or pain. This case report describes the advantages of arthroscopic treatment, including a low-invasive approach and easy accessibility to the whole intra-articular space, which can provide clear visualization of the tumorous lesion.

Efficacy of collagenase Clostridium histolyticum injection for Dupuytren's contracture in East-Asian population.

BACKGROUND: Treatment with injection of collagenase Clostridium histolyticum (CCH) has been recognized as an effective option for the Dupuytren's contracture (DC) in Europe and North America. However, there are no studies describing mid-term efficacy of CCH treatment in East-Asian population. The purpose of this study was to assess 2-year outcomes following CCH treatment in Japanese patients. METHODS: Twenty hands (28 joints) from 18 DC patients underwent CCH injection with manipulation according to the product specifications with 2-year follow-up. Patients were assessed for extension deficit on treated metacarpophalangeal (MCP) and/or proximal interphalangeal (PIP) joints before treatment, at 4 weeks and 2 years after the treatment. RESULTS: At 4 weeks after CCH treatment, contracture of treated joints significantly improved from the mean extension deficit of 45° before treatment to 3° for MCP joints, and from 41° to 14° for PIP joints (P < 0.001, <0.001, respectively). Improved contracture was maintained with 4° and 23° at 2 years after CCH treatment (P < 0.001, <0.05, respectively). Successful correction defined as ≤ 5° extension deficit was obtained in 14/16 MCP and 5/12 PIP joints at 4 weeks; of these, 11 MCP and 1 PIP joints maintained the corrected range of motion at 2-year follow-up. CONCLUSION: CCH treatment could be a useful option to improve contracture in Japanese patients. During 2-year follow-up, this treatment could provide comparable effect durability to previous studies from Western countries. Moreover, our results support the evidence that better correction of the contracture can be obtained in the MCP joints than PIP joints after CCH treatment.