Naomi Oizumi

A new nerve block procedure for the suprascapular nerve based on a cadaveric study.

HYPOTHESIS Shoulder pain after rotator cuff repair surgery is sometimes very severe. Suprascapular nerve block (SSNB) is a method used to relieve this shoulder pain, but is not always completely effective. The purpose of this study is to develop the new effective suprascapular nerve block procedure. METHODS To obtain an effective SSNB, we investigated an anatomic lesion of the sensory branches of the SSN in 8 cadavers and developed a new procedure. We evaluated its effectiveness by recording visual analog scale (VAS) scores in 8 patients experiencing severe pain after rotator cuff repair surgery before SSNB and for up to 24 hours postoperatively. RESULTS All cadaver shoulders had 2 or 3 sensory branches that just passed the scapular notch. The branches originated from the SSN, pursued the base of the coracoid process, perforated the supraspinatus muscle, and extended toward the subacromial bursa. The average VAS score of the 8 patients postoperatively was 5.4 +/- 2.7 before SSNB and improved to 2.8 +/- 1.6 immediately after SSNB, to 1.2 +/- 0.6 at 1 hour, and to 0.8 +/- 0.8 at 4 hours. Effective pain control was achieved, and SSNB presented no complications. CONCLUSION Our SSNB method is safe and effective for pain control in patients after open cuff repair. We expect it will be a useful management tool for pain relief after rotator cuff repair in the future. LEVEL OF EVIDENCE Basic science study.

Radial osteotomy for late-stage Kienböck’s disease: WEDGE OSTEOTOMY VERSUS RADIAL SHORTENING

We have reviewed 20 patients with stage-IIIB and stage-IV Kienböcks disease in order to examine the efficacy of two forms of radial osteotomy, namely radial wedge osteotomy and radial shortening. Lateral closing wedge osteotomies and radial shortenings were carried out on 11 and nine patients, respectively. There were no preoperative differences with respect to age, gender, and radiological stage. After a mean follow-up of 29 months, all patients, in both groups, had either a good or an excellent outcome. After the lateral closing wedge osteotomy, the radioscaphoid angle significantly increased and the Ståhl index significantly decreased. Progression of the degenerative changes at the radioscaphoid joint was found in two patients in this group. By contrast, there were no significant changes in any radiological parameters after radial shortening. Both procedures gave acceptable clinical results in stage-IIIB and stage-IV Kienböcks disease.

Will Preoperative Atrophy and Fatty Degeneration of the Shoulder Muscles Improve after Rotator Cuff Repair in Patients with Massive Rotator Cuff Tears

Recently, retear rate after repair for massive cuff tear have been improved through devised suture techniques. However, reported retear rate is relevant to preoperative atrophy and fatty degeneration. The purpose of this study was to investigate whether preoperative atrophy and fatty degeneration of rotator cuff muscles improve by successful repair. Twenty-four patients with massive rotator cuff tear were evaluated on the recovery of atrophy and fatty degeneration of supraspinatus and infraspinatus muscle after surgery. Atrophy was classified by the occupation ratio and fatty degeneration by modified Goutalliers classification. Both were assessed on magnetic resonance imaging (MRI) before and after the operation. When the cuff was well repaired, improvement of the atrophy and fatty degeneration were observed in a half and a one-fourth of the cases, respectively. In retear cases, however, atrophy and fatty degeneration became worse. Improvement of atrophy and fatty degeneration of the rotator cuff muscles may be expected in the cases with successful achievement of rotator cuff repair for large and massive tear.

Bone marrow stimulation at the footprint of arthroscopic surface-holding repair advances cuff repair integrity

BACKGROUND Bone marrow stimulation (BMS) at the footprint of arthroscopic rotator cuff repair has not been fully evaluated according to the preoperative tear size and surgical technique. In this study, we investigated the effect of BMS on cuff repair integrity after an arthroscopic surface-holding (ASH) repair. MATERIALS AND METHODS A total of 111 patients (mean age, 64.5 years) with chronic rotator cuff tears who underwent treatment by the ASH method with BMS by drilling of multiple holes at the footprint (67 shoulders) or without BMS (44 shoulders) were studied, and all patients were observed prospectively. Sugayas classification was used to evaluate cuff integrity by postoperative magnetic resonance imaging, with types IV and V classified as rotator cuff retears. RESULTS The mean scores for cuff integrity were 2.2 ± 0.2 and 1.7 ± 0.2 in the non-BMS and BMS groups, respectively. The mean scores were similar between the 2 groups for medium tears; however, scores for large-massive tears were significantly lower in the BMS group. The overall retear rate was 23.9% in the non-BMS group and 9.1% in the BMS group, and the distribution of repair types differed significantly. For large-massive tears, the retear rate was much higher in the non-BMS group (28.6%) than in the BMS group (4.5%), although the rates for medium tears were comparable between the 2 groups. CONCLUSIONS These findings demonstrate that applying BMS to the footprint during ASH repair results in improved cuff repair integrity, particularly in large-massive tears, and suggest the importance of biologic treatment for rotator cuff healing after arthroscopic rotator cuff repair.

Predictors of Clinical Results of Radial Osteotomies for Kienböck’s Disease

The factors affecting the clinical results after radial osteotomies for Kienböck’s disease are unknown. In the current study, we reviewed the data of 41 patients treated with radial osteotomies for Kienböck’s disease and analyzed which preoperative factors significantly affected the clinical results of these procedures. Lateral closing wedge osteotomies of the radius were done for 22 patients (six patients with Lichtman Stage II disease, three patients with Lichtman Stage IIIA disease, 12 patients with Lichtman Stage IIIB disease, and one patient with Lichtman Stage IV disease) with zero or positive ulnar variance, and radial shortenings were done for 19 patients (four patients with Stage II disease, two patients with Stage IIIA disease, 12 patients with Stage IIIB disease, and one patient with Stage IV disease) with negative ulnar variance. The mean age of the patients at surgery was 36 years and the average followup was 38 months. To statistically assess the prognostic factors, multiple regression analysis focused on the postoperative clinical score as a dependent variable and preoperative patient data as independent variables. In the current analysis, patient age was the preoperative factor most clearly predictive of clinical results after radial osteotomies for Kienböck’s disease. We think that the lower effectiveness of radial osteotomies must be considered in doing these procedures for elderly patients.

In vitro and finite element analysis of a novel rotator cuff fixation technique

The purpose of this investigation was to assess the biomechanic strength and stress dispersion at the repair site of surface-holding repair techniques for rotator cuff repair compared to the double-row technique. Eighteen bovine infraspinatus tendons were repaired using 3 different repair techniques: double-row repair, surface-holding repair with transosseous sutures, and surface-holding repair with knotless anchors. Biomechanical testing and two-dimensional finite element analysis were performed. The surface-holding repair with transosseous sutures provided 87.9% more stiffness than the double-row repair. The number of tendon-suture site failures of the surface-holding repair with transosseous sutures was smaller than the other 2 techniques. The finite element analysis showed that the surface-holding repair model had a more dispersing stress pattern compared to a double-row repair model. It suggests that these repair techniques can prevent high stress concentration compared to the double-row repair.

Interlocking intramedullary nailing for nonunion of the proximal humerus with the Straight Nail System

Nonunion of the proximal humerus is a challenging problem. Since 1996, we have performed interlocking intramedullary nailing for the treatment of proximal humeral nonunions with the Straight Nail System and bone grafting. The objective of this study was to investigate the clinical outcomes of this procedure in patients with proximal humeral nonunion. We investigated 14 consecutive patients (mean age, 74.3 +/- 8.7 years). One patient was excluded because of associated brachial plexus palsy. All but 2 were initially treated conservatively. Range-of-motion exercises were started 1 week after the operation. The mean follow-up period was 37.8 months. Union was achieved in all cases without any evidence of malunion. All patients had improved range of motion of the shoulder and were satisfied with the surgical results. Mean flexion of the shoulder was 122 degrees +/- 14 degrees, and mean external rotation was 35 degrees +/- 10 degrees. Interlocking intramedullary nailing with the Straight Nail System and bone grafting offered a successful method of stable internal fixation in these complex proximal humeral nonunion cases.

Stress distribution patterns at the coracoacromial arch in rotator cuff tear measured by computed tomography osteoabsorptiometry

When a rotator cuff tear occurs, forces compressing the humeral head toward the glenoid are disturbed, and the kinematics of the glenohumeral joint change. Therefore, stress distributions at the coracoacromial arch in cuff tear shoulders should differ from those in normal shoulders. To investigate this hypothesis, we studied stress distribution patterns at the coracoacromial arch in normal and cuff tear shoulders using a computed tomography (CT) osteoabsorptiometry method, in which bone density correlates directly with long‐term physiologic loading. Eight normal subjects and 11 patients with cuff tear were examined. The stress distributions at the undersurface of the acromion and the posterolateral surface of the coracoid process differed markedly between normal and cuff tear shoulders. In cuff tear shoulders, a high‐density area was located at the anterior or the anterolateral part of the undersurface of the acromion, while it was located at the posterior part in all but one normal shoulder. Additionally, a high‐density area was located at the superior or the lateral part of the coracoid process in most of the cuff tear shoulders; on the other hand, it was located at the base in all but one normal shoulder. We believe that the differences in stress distribution patterns are due to impingement at the coracoacromial arch in cuff tear shoulders. CT osteoabsorptiometry can provide useful information in performing coracoacromial arch decompression for cuff tear shoulders.

Recovery of sensory disturbance after arthroscopic decompression of the suprascapular nerve

BACKGROUND The existence of sensory branches of the suprascapular nerve (SSN) has recently been reported, and sensory disturbance at the lateral and posterior aspect of the shoulder has been focused on as a symptom of SSN palsy. We have performed arthroscopic release of SSN at the suprascapular notch in patients with sensory disturbance since 2006. The purposes of this study were to introduce the arthroscopic surgical technique and investigate postoperative recovery of sensory disturbance. MATERIALS AND METHODS The study included 11 men and 14 women (25 shoulders), with an average age of 63.9 years (range, 41-77 years). Arthroscopic decompression of the SSN was performed using a suprascapular nerve (SN) portal as a landmark for approaching the suprascapular notch. Sensory disturbance of the shoulder was evaluated preoperatively and postoperatively. The average follow-up was 18.5 months (range, 12-30 months). RESULTS The arthroscopic procedures were performed safely. The preoperative sensory disturbance fully recovered postoperatively in all shoulders. CONCLUSION Arthroscopic release of the SSN is a useful procedure for SSN entrapment at the suprascapular notch. The sensory disturbance at the lateral and posterior aspect of the shoulder can be used as one of the criteria of diagnosing SSN palsy, especially in shoulders with massive rotator cuff tear, in which diagnosing and assessing the treatment results of associated SSN palsy is usually difficult.

Long-Term Stress Distribution Patterns Across the Elbow Joint in Baseball Players Assessed by Computed Tomography Osteoabsorptiometry

Background: The distribution pattern of subchondral bone density is considered to highly reflect the stress distribution across a joint under long-term physiologic loading conditions. Therefore, the biomechanical characteristics over the elbow joint surface under long-term loading conditions of baseball pitching can be determined by a measurement of the distribution pattern. Hypothesis: Stress distribution over the elbow joint surface alters with long-term pitching activities. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Computed tomography (CT) imaging data from the dominant elbow of 10 nonthrowing athletes, 10 college baseball fielders, and 10 college baseball pitchers were collected for the current analysis. The distribution of subchondral bone density through the distal articular surface of the humerus was measured using a CT osteoabsorptiometry method. The quantitative analysis of the obtained data focused on location and size of the maximum density area at the articular surface. Results: The maximum density area of subchondral bone across the articular surface of the distal humerus was located in the posterior part of the trochlea in all subjects. This maximum density area was significantly increased in the pitcher group, compared with that in other groups. Additionally, the pitcher group demonstrated a significant distribution of the maximum density area in the anterior part of the capitellum. Conclusion: The results indicate that actual stress across the elbow is concentrated in the posterior part of the trochlea in humans. Baseball pitching may produce excessive or repetitive stress against not only this part, but also the anterior part of the capitellum. The majority of osteochondritis dissecans lesions affecting the elbow are found in the anterior part of the capitellum in throwing athletes. The results may support an important role of mechanical conditions in the cause of elbow osteochondritis dissecans.