Magnetic resonance imaging-based topographical differences between control and recurrent patellofemoral instability patients.

BACKGROUND: Plain films and computed tomography (CT)-based imaging were the first to establish measurements that evaluated patellar instability. Limited research has shown the efficacy of magnetic resonance imaging (MRI) in evaluating these established measurements. PURPOSE: To identify morphological differences between normal knees and those with patellofemoral instability on MRI to determine what measurements are significant and how MRI-based means differ from historical means based on radiograph and CT imaging. STUDY DESIGN: Case control study; Level of evidence, 3. METHODS: Eighty-one controls and 40 patients with recurrent patellar instability between 2006 and 2010 were reviewed. The control patients had a history and an examination negative for patellofemoral symptoms. Patients with patellar instability had a history of at least 2 frank patellofemoral joint dislocations (PFJDs). The MRI images were obtained on the nonweightbearing knee in full extension. Measurements of patellar tilt, trochlear morphologic characteristics, and tibial tuberosity-trochlear groove (TTTG) distance were evaluated on axial slices, and patellar height was measured on sagittal images. Trochlear shape was assessed at the proximal and distal trochlea. RESULTS: All measurements of patellar tilt (mean ± SD) were found to be significantly different between the 2 groups. For patellar height, the Insall-Salvati ratio (control, 1.08 ± 0.02; PFJD, 1.26 ± 0.03) and Caton-Deschamps ratio (control, 1.13 ± 0.02; PFJD, 1.29 ± 0.03) proved to be significantly different. Trochlear morphologic characteristics had numerous measurements prove to be significantly different proximally and distally. These included classic measurements such as sulcus angle (control, 148.48° ± 0.94°; PFJD, 165.57° ± 2.65°) and lateral trochlear inclination (control, 21.27° ± 0.66°; PFJD, 13.31° ± 1.36°) proximally and less established measurements such as the ratio of external (lateral) trochlea to internal (medial) trochlea (control, 1.51 ± 0.05; PFJD, 2.11 ± 0.17), a measurement of facet asymmetry. CONCLUSION: The MRI-based patellar tilt measures proved to be an excellent group of measurements for delineating between controls and those with instability. Patella alta ratios, such as Insall-Salvati and Caton-Deschamps, demonstrated a statistically significant difference between normal and recurrent dislocators. Trochlear measurements proved significantly different at the proximal and distal trochlea. Our findings demonstrate that MRI is appropriate to help discern recognized pathologic abnormalities that characterize patellofemoral instability.

A trainee-based randomized comparison of stimulating interscalene perineural catheters with a new technique using ultrasound guidance alone.

OBJECTIVE: Compared to the well-established stimulating catheter technique, the use of ultrasound guidance alone for interscalene perineural catheter insertion is a recent development and has not yet been examined in a randomized fashion. We hypothesized that an ultrasound-guided technique would require less time and produce equivalent results compared to electrical stimulation (ES) when trainees attempt interscalene perineural catheter placement. METHODS: Preoperatively, patients receiving an interscalene perineural catheter for shoulder surgery were randomly assigned to an insertion protocol using either ultrasound guidance with a nonstimulating catheter or ES with a stimulating catheter. The primary outcome was the procedural duration (in minutes), starting when the ultrasound probe (ultrasound group) or catheter insertion needle (ES group) first touched the patient and ending when the catheter insertion needle was removed after catheter insertion. RESULTS: All ultrasound-guided catheters (n = 20) were placed successfully and resulted in surgical anesthesia versus 85% of ES-guided catheters (n = 20; P = .231). Perineural catheters placed by ultrasound (n = 20) took a median (10th-90th percentiles) of 8.0 (5.0-15.5) minutes compared to 14.0 (5.0-30.0) minutes for ES (n = 20; P = .022). All catheters placed according to the protocol in both treatment groups resulted in a successful nerve block; however, 1 patient in the ES group had local anesthetic spread to the epidural space. There was 1 vascular puncture using ultrasound guidance compared to 5 in the ES-guided catheter group (P = .182). CONCLUSIONS: Trainees using a new ultrasound-guided technique can place inter-scalene perineural catheters in less time compared to a well-documented technique using ES with a stimulating catheter and can produce equivalent results.

Ultrasound guidance versus electrical stimulation for femoral perineural catheter insertion.

OBJECTIVE: Continuous femoral nerve blocks provide potent analgesia and other benefits after knee surgery. Perineural catheter placement techniques using ultrasound guidance and electrical stimulation (ES) have been described, but the optimal method remains undetermined. We tested the hypothesis that ultrasound guidance alone requires less time for femoral perineural catheter insertion and produces equivalent results compared with ES alone. METHODS: Preoperatively, patients receiving a femoral perineural catheter for knee surgery were randomly assigned to either ultrasound guidance with a nonstimulating catheter or ES with a stimulating catheter. The primary outcome was the catheter placement procedure time (minutes) starting when the ultrasound transducer (ultrasound group) or catheter insertion needle (ES group) first touched the patient and ending when the catheter insertion needle was removed after catheter insertion. RESULTS: Perineural catheters placed with ultrasound guidance (n = 20) took a median (10th-90th percentiles) of 5.0 (3.9-10.0) minutes compared with 8.5 (4.8-30.0) minutes for ES (n = 20; P = .012). All ultrasound-guided catheters were placed according to the protocol (n = 20) versus 85% of ES-guided catheters (n = 20; P = .086). Patients in the ultrasound group had a median procedure-related discomfort score of 0.5 (0.0-3.1) compared with 2.5 (0.0-7.6) for the ES group (P = .015). There were no vascular punctures with ultrasound guidance versus 4 in the ES group (P = .039). CONCLUSIONS: Placement of femoral perineural catheters takes less time with ultrasound guidance compared with ES. In addition, ultrasound guidance produces less procedure-related pain and prevents inadvertent vascular puncture.

Continuous interscalene brachial plexus block via an ultrasound-guided posterior approach: a randomized, triple-masked, placebo-controlled study.

BACKGROUND: The posterior approach for placing continuous interscalene catheters has not been studied in a controlled investigation. In this randomized, triple-masked, placebo-controlled study, we tested the hypothesis that an ultrasound-guided continuous posterior interscalene block provides superior postoperative analgesia compared to a single-injection ropivacaine interscalene block after moderately painful shoulder surgery. METHODS: Preoperatively, subjects received a stimulating interscalene catheter using an ultrasound-guided, in-plane posterior approach. All subjects received an initial bolus of ropivacaine. Postoperatively, subjects were discharged with oral analgesics and a portable infusion device containing either ropivacaine 0.2% or normal saline programmed to deliver a perineural infusion over 2 days. The primary outcome was average pain on postoperative day (POD) 1 (scale: 0-10). Secondary outcomes included least and worst pain scores, oral opioid requirements, sleep disturbances, patient satisfaction, and incidence of complications. RESULTS: Of the 32 subjects enrolled, 30 perineural catheters were placed per protocol. Continuous ropivacaine perineural infusion (n = 15) produced a statistically and clinically significant reduction in average pain (median [10th-90th percentile]) on POD 1 compared with saline infusion (n = 15) after initial ropivacaine bolus (0.0 [0.0-5.0] versus 3.0 [0.0-6.0], respectively; P < 0.001). Median oral opioid consumption (oxycodone) was lower in the ropivacaine group than in the placebo group on POD 1 (P = 0.002) and POD 2 (P = 0.002). Subjects who received a ropivacaine infusion suffered fewer sleep disturbances than those in the placebo group (P = 0.005 on POD 0 and 1 nights) and rated their satisfaction with analgesia higher than subjects who received normal saline (P < 0.001). CONCLUSIONS: Compared to a single-injection interscalene block, a 2-day continuous posterior interscalene block provides greater pain relief, minimizes supplemental opioid requirements, greatly improves sleep quality, and increases patient satisfaction after moderate-to-severe painful outpatient shoulder surgery.

Arthroscopic versus mini-open rotator cuff repair: a comprehensive review and meta-analysis.

BACKGROUND: Controversy remains regarding the results of all arthroscopic rotator cuff repairs compared with the mini-open approach. The purpose of this study was to perform a comprehensive literature search and meta-analysis of clinical trials comparing the results of arthroscopic rotator cuff repairs and mini-open rotator cuff repairs. HYPOTHESIS: There is no difference between the clinical results obtained from all arthroscopic rotator cuff repairs compared with mini-open repairs. STUDY DESIGN: Meta-analysis. METHODS: A computerized search of articles published between 1966 and July 2006 was performed using MEDLINE and PubMed. Additionally, a search of abstracts from 4 major annual meetings each held between 2000 and 2005 was performed to identify Level I to III studies comparing the results of arthroscopic rotator cuff repair and mini-open repair. Studies that included follow-up of an average of over 2 years and a minimum of 1 year and included the use of 1 of 4 validated functional outcome scores used to study shoulder injuries were included in the present meta-analysis. All outcome scores were converted to a 100-point scale to allow for outcome comparison. RESULTS: Five studies that met the inclusion criteria were identified. There was no difference in functional outcome scores or complications between the arthroscopic and mini-open repair groups. CONCLUSION: Based on current literature, there was no difference in outcomes between the arthroscopic and mini-open rotator cuff repair techniques.