The effect of experimental shoulder pain on contralateral muscle force and activation.

Inhibition of rotator cuff activation and force after local experimental pain has been previously shown. Clinically, strength is often indexed to the uninvolved side in order to quantify deficits during injury and recovery. This study assessed the effect of experimental subacromial pain on contralateral shoulder external rotation (ER) force and activation. We hypothesized that subacromial pain would not affect contralateral shoulder external rotation force and voluntary activation (VA) of the contralateral infraspinatus because we believe that the effects of acute experimental pain will largely exert an ipsilateral, spinal segmental effect. Twenty healthy adults were tested. External rotation force and VA were tested while participants performed maximum voluntary isometric contractions of shoulder external rotation, during which a brief electrical stimulus was applied to the infraspinatus muscle at an intensity that maximized external rotation force. To elicit pain, 1.5 ml of 5% hypertonic saline was injected into the contralateral subacromial space. Mean (SD) pain immediately after injection was 6.3/10 (0.85) resulting in a 7.6% decline in contralateral external rotation force (p < .01) and 3.3% decline in infraspinatus muscle VA (p = .48). A subset of participants (n = 9) showed a more substantial decline in both force (15.4%; p < .000001; d = -3.53) and VA (8.7%; p = .045; d = -0.98). Experimental shoulder pain had a modest effect on contralateral ER force and VA in a subset of participants; therefore, it may be important to index or compare strength bilaterally throughout rehabilitation to capture this bilateral effect as pain resolves.

Complications of open reduction and internal fixation of ankle fractures in patients with positive urine drug screen.

We conducted a study to identify complications associated with open treatment of ankle fractures in patients who tested positive for illicit drugs on urine drug screen (UDS). We hypothesized that patients who had a history of positive UDS and underwent open reduction and internal fixation of an ankle fracture would have a higher incidence of major and minor complications. We retrospectively reviewed the cases of 142 patients who had surgical stabilization of an ankle fracture during a 3-year period. Patients with a history of positive UDS were compared with matched controls with negative UDS. Outcomes measures included nonunion, malunion, and superficial or deep infection. Fisher exact test, Wilcoxon rank sum test, and univariate logistic regression were used to determine statistical significance. There were no significant differences in age, sex, fracture type, incidence of diabetes, or incidence of open fracture between the groups. Incidence of nonunion was higher in patients with positive UDS (P = .01), as was incidence of deep infection (P = .05). Incidence of pooled major complications was also higher in positive UDS patients (P = .03). Patients with a history of illicit drug use, as evidenced by positive UDS, are at increased risk for perioperative complications during treatment for ankle fracture.

Stockinette application over a non-prepped foot risks proximal contamination.

This study sought to determine if there was an increased risk for surgical site contamination during stockinette application for a lower extremity surgery draping technique. Utilizing a simulated, sterile surgical field, stockinettes were applied over 10 cadaver lower extremities that were contaminated with non-pathogenic Escherichia coli on the foot. Of those, five specimens were then disinfected with Chloroprep and another 5 did not undergo any disinfection. All the specimens in which the stockinette was applied over a non-prepped foot showed proximal contamination. No contamination occurred in any of the specimens where the foot was disinfected. Stockinette can be a source of surgical site contamination when placed over a non-prepared foot.

Experimental pain inhibits infraspinatus activation during isometric external rotation.

BACKGROUND: The effect of pain on muscle activation is poorly understood. This study examined the effects of acute experimental pain on rotator cuff muscle force and voluntary activation (VA). We hypothesized that acute subacromial pain would cause inhibition of infraspinatus VA with a corresponding decrease in external rotation force. MATERIALS AND METHODS: Seventeen healthy adults with no known shoulder pathology were tested. Isolated external rotation force was tested on a dynamometer. Participants performed 2 baseline maximum voluntary isometric contractions of external rotation, during which maximal electrical stimulation was used to assess VA. To elicit pain, 1.5 mL 5% hypertonic saline was injected into the subacromial space, and testing of maximum voluntary isometric contractions force and VA was repeated 3 times at 5-minute intervals. RESULTS: Mean ± standard deviation initial pain from the injection was 6.6 ± 1.3 points of 10 possible and produced a 32.8% decline in force and a 22.7% decline in VA (P < .05). Pain diminished over a 10-minute period. As pain resolved, force and VA improved (P < .0125). There was a strong relationship between force and VA (r(2) = 0.78, P < .05) and a moderate relationship between pain and VA (r(2) = 0.31, P < .05). CONCLUSIONS: Experimental subacromial pain elicits a decline in force and VA of the infraspinatus. Although this study only examines acute experimental pain, it supports the concept that pain affects rotator cuff muscle recruitment and function, which may contribute to abnormal shoulder mechanics in patients with rotator cuff pathology.

A comparison of glenoid morphology and glenohumeral range of motion between professional baseball pitchers with and without a history of SLAP repair.

PURPOSE: We sought to examine the relation among glenoid morphology, glenohumeral range of motion (ROM), and history of shoulder injury in professional baseball pitchers. METHODS: We studied 58 professional baseball pitchers. Internal rotation (IR) and external rotation (ER) ROM was measured at 90° of abduction. Horizontal adduction (HAdd) ROM was also measured. Glenoid superior inclination and glenoid retroversion (GRV) were then measured radiographically. Separate mixed-model analyses of variance were used to compare dependent measures between the dominant and nondominant shoulders of pitchers with or without a history of SLAP repair. Significant interaction effects were interpreted by use of a test for simple main effects (α = .05). RESULTS: GRV was significantly greater on the dominant side (8.7° ± 5.6°) versus nondominant side (5.5° ± 5.2°) (P = .001), whereas glenoid superior inclination was equivalent (99.5° ± 4.3° for dominant side v 99.2° ± 4.4° for nondominant side, P = .853). Post hoc analysis indicated that pitchers with a history of SLAP repair did not display an adaptive increase in dominant GRV compared with nondominant GRV (P = .016). There were no statistical differences between groups for ER (P = .29), IR (P = .39), or HAdd (P = .39). The dominant shoulder displayed greater ER (mean increase, 6.2° ± 12.2°) with a complementary decrease in IR (mean decrease, 5.8° ± 13.2°) and HAdd (mean decrease, 8.9° ± 13.7°) compared with the nondominant side. CONCLUSIONS: Our findings suggest that the development of increased GRV in the dominant shoulder of professional baseball pitchers may be a protective adaptive change not reflected in glenohumeral ROM measures. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

The inter-rater reliability and diagnostic accuracy of patellar mobility tests in patients with anterior knee pain.

BACKGROUND: Patients with patellofemoral pain syndrome (PFPS) often have nonspecific findings on clinical examination. A tight knee and diminished patellar mobility in particular, may contribute to anterior knee pain. METHODS: Qualifying patients with anterior knee pain of > 4 weeks were sequentially examined by 2 physicians who used the patellar mobility tests. The tests evaluated for diminished patellar translation superior-inferiorly and medial-laterally, diminished patellar tendon mobility, and absent inferior pole tilt. Each of the 4 tests was scored as 1 (diminished/absent) or 0 (nondiminished/normal), with the sum of the scores determining the patellar mobility scale. Inter-rater reliability and diagnostic accuracy were determined and analyzed. Receiver operating characteristic analysis was used to determine the capacity of the patellar mobility scale to predict PFPS. RESULTS: 98 patients participated in the study. The inter-rater reliability for the 4 individual patellar mobility tests was moderately strong, with diminished medial-lateral patellar mobility demonstrating the strongest reliability (Kappa value [K], 0.59; 95% confidence interval [CI], 0.42-0.72), followed by diminished superior-inferior mobility (K), 0.55; 95% CI, -0.37 to 0.69), inferior pole tilt (K, 0.48; 95% CI, -0.28 to 0.61), and patellar tendon mobility (K, 0.45; 95% CI, -0.27 to 0.56). The diagnostic accuracy of the individual patellar mobility tests in diagnosing PFPS was fair to moderate, with the individual diminished patella tendon mobility test having the highest level of diagnostic accuracy (sensitivity, 49%; specificity, 83%; likelihood ratio [LR] ± 2.8; 95% CI, 1.3-7.3) and also having the highest positive predictive value (0.88). Diminished medial-lateral mobility was second in diagnostic accuracy (sensitivity, 54%; specificity, 69%; LR ± 1.8; 95% CI, 0.9-3.6). Receiver operating characteristic analysis showed only moderate levels of diagnostic capacity (area under the curve, 0.65) because combining all 4 patellar mobility tests to form the patellar mobility scale did not improve the diagnostic accuracy. CONCLUSION: The clinical importance of diminished patellar and/or patellar tendon mobility findings in the evaluation of patients with anterior knee pain remains unclear. We determined that individual patellar mobility tests had moderate levels of inter-rater reliability, the best agreement found with medial-lateral mobility. The accuracy of the patellar mobility scale for diagnosing PFPS was marginal. As a tool, this cluster of examination techniques may be used by physicians to better understand their patients' conditions and descriptively communicate their findings. However, the patellar mobility scale cannot be used alone for determining the diagnosis of PFPS, as defined in our study. Future studies aim to determine whether post-treatment symptomatic improvements correlate with an improvement on the patellar mobility scale.

Two-layer repair of a chronic patellar tendon rupture: a novel technique and literature review.

Neglected rupture of the patellar tendon can be a debilitating problem. Various techniques have been described to reconstruct chronic tears. This article presents a simple technique for 2-layer repair of chronic patellar tendon ruptures using Achilles allograft augmentation. A manual laborer presented to the orthopedic clinic 5 years after sustaining an unrecognized patellar tendon rupture. Despite this significant delay between injury and reconstruction, our patient enjoyed excellent range of motion and full quadriceps strength 19 months after reconstruction. We believe our technique provides several advantages. By design, the tibial trough was shallower than the depth of the bone block, thus minimizing patellofemoral contact pressure. Transpatellar drilling with the use of a Beath pin makes suture passage easier and provides strong repair permitting early mobilization. Furthermore, our technique spares the remaining native patellar tendon tissue, preserves its insertions, and does not require the use of a tension cerclage wire.

Evaluation of the upper esophageal sphincter (UES) using simultaneous high-resolution endoluminal sonography (HRES) and manometry.

The aim of this study was to characterize the motion, morphology, and pressure of the upper esophageal sphincter (UES). The UES and its surrounding structures were evaluated in seven normal subjects and four human cadavers, using simultaneous high-resolution endoluminal sonography and manometry. The UES musculature on ultrasound is a C-shaped structure with an angle of 107 +/- 19 degrees. The mean peak resting UES pressure was 74 mm Hg, with a total cross-sectional area (CSA) of 0.87 +/- 0.33 cm2. During swallowing, the UES moved in an orad direction. Localizing the UES sonographically, the peak UES pressure in the cadavers was 19.7 +/- 10.0 mm Hg. The UES has a greater muscular CSA and resting pressure than the upper esophageal body. In the cadaver studies, the UES was imaged in conjunction with a significant increase in pressure, indicating that the pressure is due to passive mechanical conformational changes.