John F. Orwin

Suprascapular nerve entrapment by ganglion cysts: a report of six cases with arthroscopic findings and review of the literature.

Suprascapular nerve entrapment by a ganglion cyst can produce pain and shoulder dysfunction. We report six cases with the associated arthroscopic intraarticular findings of a posterior capsulolabral injury (only the second such description) and review the literature. Based on the current literature and our experience, we document our treatment algorithm for suprascapular nerve entrapment secondary to a ganglion cyst. We believe it is necessary to evaluate and treat the intraarticular pathology as well as the ganglion cyst/nerve entrapment to successfully manage these patients.

Width of high signal and extension posterior to biceps tendon as signs of superior labrum anterior to posterior tears on MRI and MR arthrography

OBJECTIVE The purpose of our study was to determine the accuracy of two signs for superior labrum anterior to posterior (SLAP) tears: increased width of high signal between the superior labrum and glenoid, and high signal posterior to the biceps tendon. MATERIALS AND METHODS Forty-one patients with SLAP tears and 40 patients without a tear at surgery who had undergone MRI or MR arthrography were retrospectively evaluated. The MR studies were combined and interpreted in a blinded manner. The reviewers measured the width of high signal that extended to the articular surface on oblique coronal images and determined whether the high signal extended posterior to the biceps. A Students t test was used to determine statistical significance between the means of the signal width. RESULTS High-signal width was greater in patients with a SLAP tear than in the control group on both MRI and MR arthrography (both p = 0.003). The sensitivity and specificity of at least 2.0 mm on MRI are 39% (11/28) and 89% (24/27) and at least 2.5 mm on MR arthrography are 46% (6/13) and 85% (11/13). The sensitivity and specificity of high signal posterior to the biceps are 54% (15/28) and 74% (20/27) on MRI and 69% (9/13) and 54% (7/13) on MR arthrography. CONCLUSION Increased width of high signal has a moderate specificity but a poor positive predictive value for distinguishing a SLAP tear from a normal recess. In addition, labral signal posterior to the biceps tendon is not rare in patients with no SLAP tear.

Diagnosis of partial and complete rotator cuff tears using combined gradient echo and spin echo imaging

Most magnetic resonance (MR) studies evaluating the rotator cuff for tears have used T2-weighted imaging in the coronal oblique and sagittal oblique planes, T2*-weighted gradient echo imaging, however, has advantages over spin echo imaging, including contiguous slices without cross-talk, high contrast around the cuff, and intrinsically shorter imaging times which can be used to increase the number of signals averaged and thus improve the signal-to-noise ratio. We reviewed the shoulder MR scans of 87 consecutive patients who underwent both a MR scan and a shoulder arthroscopy during which the size of tears, if present, was graded. The reviewers were blinded as to the history and arthroscopic results. The MR scans included oblique coronal T2*-weighted gradient echo and oblique sagittal T2-weighted spin echo images. MR cuff grades were correlated with arthroscopic findings. For complete tears, the sensitivity of MR was 0.91 and the specificity 0.95. For partial tears, the sensitivity was 0.74 and the specificity 0.87. This accuracy is similar to two-plane T2-weighted imaging as previously reported in the literature. There was a statistically significant correlation (p < 0.0005) between the cuff grade as determined by MR and the arthroscopic findings.

THE EFFECT OF TOURNIQUET USE ON POSTOPERATIVE STRENGTH RECOVERY AFTER ARTHROSCOPIC MENISCECTOMY

The purpose of this prospective study was to determine the effect of pneumatic tourniquet use during arthroscopic meniscectomy on postoperative recovery of quadriceps and hamstring strength. Thirty-four patients with no ligamentous instability underwent arthroscopic meniscectomy after random assignment to the tourniquet or no tourniquet group. Tourniquet pressure was determined with a nomogram that considered thigh circumference and systolic blood pressure at time of induction. Quadriceps and hamstring strengths were tested preoperatively and at 1 week and 4 weeks postoperatively on a Biodex isokinetic dynamometer and expressed as a percentage of the uninvolved side. No significant differences in quadriceps or hamstring strength were noted between groups at any time periods. The findings of this study indicate that recovery of quadriceps and hamstring strength after arthroscopic meniscectomy is not adversely affected by tourniquet use if tourniquet times and pressures are carefully controlled.

Fat-suppressed fast spin-echo mid-TE (TE[effective]=34) MR images: comparison with fast spin-echo T2-weighted images for the diagnosis of tears and anatomic variants of the glenoid labrum

Abstract Objective. To compare the sensitivity, specificity, and accuracy of fat-suppressed fast spin-echo (FSE) mid-TE (TE[effective]=34) images with fat-suppressed FSE T2-weighted images for the diagnosis of labral abnormalities. Design and patients. The study included 27 consecutive patients who had axial fat-suppressed FSE T2-weighted and fat-suppressed FSE mid-TE MR images, and had labral abnormalities diagnosed at arthroscopy. The acquisition time was about 5 min for each sequence, but the mid-TE sequence allowed a higher spatial resolution than the T2-weighted images (256×256 versus 256×192). Twenty-eight age-matched patients with arthroscopically normal labra were included as a control group. The labrum was graded on the MR images as normal or abnormal separately by two musculoskeletal radiologists who were masked to the history and arthroscopic results. The surgical findings were used as the gold standard for calculating the sensitivity, specificity, and accuracy for interpreting the correct location of a labral abnormality. The sensitivity, specificity, and accuracy for the two sequences were compared with a McNemar test, and significance defined as P<0.05. Results. For observer 1, the sensitivity for labral abnormalities was 0.59 on the T2-weighted images, and 0.78 on the mid-TE images (P=0.12). The specificity was 0.54 for the T2-weighted, and 0.64 for the mid-TE images (P=0.51). The accuracy was 0.56 for the T2-weighted, and 0.71 for the mid-TE images (P=0.08). For observer 2, the sensitivity/specificity/accuracy was 0.67/0.93/0.80 for the T2-weighted, and 0.70/0.86/0.78 for the mid-TE images (all P>0.5). Conclusion. In this small study there is no statistically significant difference for demonstrating labral abnormalities between FSE T2-weighted images, and higher-resolution fat-suppressed FSE mid-TE (TE[effective]=34) images obtained with a similar acquisition time. Although there was a general trend toward higher sensitivity and accuracy with the mid-TE sequence, particularly for one of the two observers, a larger study is needed to determine whether this is the preferred single axial pulse sequence for conventional MR imaging of the labrum.

Effect of field of view on MR diagnosis of rotator cuff tears

AbstractPurpose. To determine the effect of decreasing the field of view (FOV) on the accuracy of MR for diagnosing rotator cuff tears. Material and methods. One hundred shoulder MR scans with surgical correlation were evaluated for the presence or absence of a cuff tear. The sensitivity and specificity of MR relative to the surgical results were determined for the 59 patients scanned with a 24-cm FOV, and the 41 patients scanned with an 18-cm FOV. All other imaging parameters including acquisition time were identical. The sensitivity and specificity of the two groups were compared using a t-test. Results. The specificity of MR for diagnosing a rotator cuff tear improved from 0.65 for the 24-cm FOV group to 0.89 for the 18-cm FOV group (P = 0.04). The sensitivity changed from 0.91 to 0.96 (P = 0.25). Conclusion. Reducing the FOV from 24 cm to 18 cm results in a statistically significant improvement in specificity of MR for diagnosing rotator cuff tears.

Arthroscopy on Anticoagulated Patients: A Retrospective Evaluation of Postoperative Complications

Anticoagulation is commonly needed for multiple medical conditions. The indications to discontinue anticoagulation for a simple procedure are controversial. Other surgical subspecialties have shown that keeping patients on warfarin during a simple procedure is safe. The purpose of this retrospective study was to evaluate the postoperative complications encountered for patients undergoing simple arthroscopic procedures while on warfarin. We hypothesized that anticoagulated patients undergoing simple arthroscopic procedures would have few surgical bleeding complications.Arthroscopic procedures performed over a 10-year period on warfarin-anticoagulated patients were retrospectively evaluated. Data collected included the procedure and orthopedic problem, the type of anesthesia, the medical condition requiring anticoagulation, the international normalized ratio (INR) at surgery, and all postoperative complications (bleeding, hematoma, delayed healing, prolonged postoperative course, infection, and medical complication). Twenty-four patients met the inclusion criteria. All had abnormal INR levels at time of surgery. Four patients were operated on emergently for septic joints, and 20 patients had elective arthroscopic procedures (10 knees, 10 shoulders). There were no major intraoperative bleeding problems. Seven patients had minor postoperative surgical complications: 2 prolonged effusions and 5 prolonged ecchymosis. No medical complications were seen. Oral warfarin appeared to be a safe alternative to manipulating anticoagulation during the preoperative period for simple arthroscopic procedures. Minor bleeding complications consisting of ecchymosis were seen, but no medical complications were identified.

Concentric and eccentric shoulder rehabilitation biomechanics.

Abstract The use of an impulse-momentum (IM) exercise technique was investigated for end-stage shoulder rehabilitation. The objectives of this study were to: (a) quantify the net shoulder joint forces and moments while using an IM system and (b) test the influence of gender and muscle loading type (concentric or eccentric) on kinetic and kinematic parameters. Fourteen healthy adults (eight males, six females) performed a repeated measures experiment on an instrumented device utilizing a cabled shuttle system. While maintaining 90° of shoulder abduction and 90° of elbow flexion, the subjects externally rotated their upper arm from 0° to 90° (concentric acceleration) and then internally rotated their upper arm back from 90° to the 0° position (eccentric deceleration). Shoulder joint forces and moments as well as rotational work and power were calculated using inverse dynamics (free-body forces and moments calculated at intersegmental joint centres). Overall concentric peak forces and moments were greater than eccentric peak forces and moments (P < 0.0001). Joint forces and moments reached a maximum during the initial phase of concentric loading (0° to 45°) compared with any other rotational position in the loading cycle (concentric 45° to 90° or eccentric 90° to 0°). The results also indicate that males experienced higher (P < 0.0001) average resultant peak joint forces (concentric 0° to 45°=108.0 N and eccentric 90° to 45°=87.2 N) than females (concentric 0° to 45°=74.7 N and eccentric 45° to 0°=56.0 N). In addition, males experienced higher (P < 0.0001) average resultant peak joint moments (concentric 0° to 45°=30.4 N m and eccentric 45° to 0°=21.0 N m) than females (concentric 0° to 45°=19.7 N m and eccentric 45° to 0°=12.8 N m).