Fluoroscopic sniff test as a diagnostic tool for phrenic nerve injury in patients with traumatic brachial plexus injury.

OBJECTIVE: Traumatic brachial plexus injury (BPI) is a high-morbidity condition with an escalating incidence. One of the treatment options is neurotization using the ipsilateral phrenic nerve. Therefore, diagnosis of nerve dysfunction is a crucial step in preoperative planning. This study aimed to assess the accuracy and reliability of the fluoroscopic sniff test for preoperative diagnosis of phrenic nerve injury in patients with traumatic BPI. METHODS: The study was conducted from June 2019 to August 2023 at a tertiary care hospital. A preoperative fluoroscopic sniff test was performed. During brachial plexus surgery, direct phrenic nerve stimulation was conducted as a gold standard of phrenic nerve function. Two nonoperating orthopedic surgeons interpreted the accuracy and reliability of the test. RESULTS: Seventy-four patients with traumatic BPI (66 males and 8 females) with a median age of 26 years were enrolled. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the fluoroscopic sniff test were 90.9% (95% CI 75.7%-98.1%), 100% (95% CI 91.4%-100%), 100% (95% CI 88.4%-100%), 93.2% (95% CI 82.3%-97.6%), and 95.9% (95% CI 88.6%-99.2%), respectively. Interobserver reliability showed excellent agreement (κ = 1, p < 0.001). CONCLUSIONS: The fluoroscopic sniff test was proven to be an accurate, reliable, and simple tool to evaluate phrenic nerve function in patients with traumatic BPI. Preoperative testing should be performed to reduce operative time to identify the phrenic nerve as a donor for nerve transfer surgery in cases in which no function is detected from the fluoroscopic sniff test.

Effect of shorter nerve graft and selective motor branch of recipient nerve on nerve transfer surgery for elbow flexion in patients with brachial plexus injury.

OBJECTIVE: The spinal accessory nerve (SAN) is commonly used as a donor nerve for reinnervation of elbow flexors in brachial plexus injury (BPI) reconstruction. However, no study has compared the postoperative outcomes between SAN-to-musculocutaneous nerve (MCN) transfer and SAN-to-nerve to biceps (NTB) transfer. Thus, this study aimed to compare the postoperative time to recovery of elbow flexors between the two groups. METHODS: A total of 748 patients who underwent surgical treatment for BPI between 1999 and 2017 were retrospectively reviewed. Among them, 233 patients were treated with nerve transfer for elbow flexion. Two techniques were used to harvest the recipient nerve: the standard dissection technique and the proximal dissection technique. The postoperative motor power of elbow flexion was assessed every month for 24 months using the Medical Research Council (MRC) grading system. Survival and Cox regression analyses were used to compare the time to recovery (MRC grade ≥ 3) between the two groups. RESULTS: Of the 233 patients who underwent nerve transfer surgery, there were 162 patients in the MCN group and 71 patients in the NTB group. At 24 months after surgery, the MCN group had a success rate of 74.1%, and the NTB group had a success rate of 81.7% (p = 0.208). When compared with the MCN group, the NTB group had a significantly shorter median time to recovery (19 months vs 21 months, p = 0.013). Only 11.1% of patients in the MCN group regained MRC grade 4 or 5 motor power 24 months after nerve transfer surgery compared with 39.4% patients in the NTB group (p < 0.001). Cox regression analysis showed that the SAN-to-NTB transfer in combination with the proximal dissection technique was the only significant factor affecting time to recovery (HR 2.33, 95% CI 1.46-3.72; p < 0.001). CONCLUSIONS: SAN-to-NTB transfer in combination with the proximal dissection technique is the preferred nerve transfer option for restoration of elbow flexion in traumatic pan-plexus palsy.

Risk prediction model for unsuccessful elbow flexion recovery after nerve transfer surgery in patients with brachial plexus injury.

OBJECTIVE: Nerve transfer surgery has been a mainstay treatment of brachial plexus injury, with varying success rates. Patients undergoing unsuccessful surgery are left with a useless limb for at least 2 years. Preoperative prediction has become a topic of interest to avoid an unsuccessful nerve transfer surgery. This study aimed to find strong predictive factors and develop a prediction model for unsuccessful functional elbow flexion recovery 2 years after a nerve transfer surgery in patients with brachial plexus injury. METHODS: This retrospective study reviewed the medical records of 987 patients with traumatic brachial plexus injury who underwent brachial plexus surgery by five hand and microsurgery surgeons at a single tertiary care referral center from December 2001 to July 2018. Four hundred thirty-three patients were eligible for analysis. Patient demographic data, injury factors, surgical details, and postoperative factors were collected. Multivariable logistic regression was used to identify strong prognostic factors for unsuccessful nerve transfer surgery for elbow flexion. A simplified model was developed by rounding the coefficient to the nearest 0.5 score or an integer. Both original and simplified models were validated using the Hosmer-Lemeshow goodness-of-fit test and bootstrapping. RESULTS: A full, original prognostic model from a stepwise backward logistic regression consisted of a BMI ≥ 23 kg/m2 (p = 0.015), smoking (p = 0.046), total arm-type injury (p = 0.033), donor nerve (p < 0.001), associated upper-extremity fracture (p = 0.013), and associated ipsilateral vascular injury (p = 0.095). The areas under the receiver operating characteristic curve of the original and simplified models were 0.765 and 0.766, respectively. The Hosmer-Lemeshow test showed good agreement of predicted and observed probability of the original (p = 0.49) and simplified (p = 0.19) models. Bootstrapping estimated an average optimism (1.9%) in the original model and minimal optimism (0.1%) in the simplified model. CONCLUSIONS: The prediction model for failed elbow flexion recovery after nerve transfer surgery in traumatic brachial plexus injury was developed with good predictive value and internal validity. An alternative treatment, i.e., primary free functioning muscle transfer, should be offered in preoperative counseling in cases of a very high risk of failure.

Dorsal proximal interphalangeal joint tenderness is associated with prolonged postoperative pain after A1 pulley release for trigger fingers.

BACKGROUND: In some trigger finger patients, tenderness is found in the dorsal proximal interphalangeal (PIP) joint. The etiology and prevalence of this condition are unclear. Furthermore, surgical outcomes for trigger fingers with coexisting dorsal PIP tenderness have not been reported. This study (1) determined the prevalence and risk factors for PIP joint tenderness in trigger fingers and (2) compared postoperative outcomes for trigger fingers with and without joint tenderness. METHODS: This prospective cohort study was conducted between August 2018 and March 2020. We enrolled 190 patients diagnosed with single-digit trigger fingers undergoing open A1 pulley release. The incidence, demographic data, and surgical outcomes of patients with dorsal PIP tenderness were investigated. Factors associated with tenderness were analyzed, including patient occupation, finger involvement, trigger finger grading, duration of symptoms, previous corticosteroid injections, and presence of diabetes mellitus. A numeric pain scale, a patient-specific functional scale, and the range of motion were evaluated preoperatively and 1, 2, and 6 weeks after surgery, with telephone follow-ups at 3 and 6 months. RESULTS: Of 190 patients, 46.8% had tenderness of the dorsal PIP joint. Patients with joint tenderness had significantly more overall postoperative pain for up to 6 weeks and reported residual minor pain for up to 3 months. The functional scale and range of motion of the 2 groups did not differ during follow-up. The only risk factor observed was the occupation of the patients. CONCLUSION: Dorsal PIP tenderness is more common in trigger fingers than previously thought. It is also associated with higher and prolonged levels of postoperative pain after A1 pulley release. Therefore, patients with pre-existing PIP tenderness should be informed about the possibility of sustaining residual minor pain for up to 3 months after surgery. LEVEL OF EVIDENCE: II.

Comparative clinical and radiographic outcomes between early and delayed wrist mobilization after volar fixed-angle plate fixation of distal radius fracture.

Postoperative immobilization protocols after volar fixed-angle plate fixation of distal radius fractures (DRF) vary among surgeons. This study aimed to compare functional outcomes, radiographic parameters, and complications between early and delayed mobilization after volar fixed-angle plate fixation of DRF. This study is a randomized controlled trial. The early group was allowed to perform wrist motion exercise immediately after surgery and the delayed group was allowed to perform it after 2 weeks of external immobilization. Postoperative patient-rated wrist evaluation (PRWE), disabilities of arm, shoulder, and hand (DASH), wrist range of motion, visual analog scale (VAS) pain score, and grip strength were evaluated. Forty-eight patients with DRF were enrolled and randomly allocated to the early or delayed mobilization groups. The PRWE, DASH, VAS pain score, grip strength, and wrist motion of both groups significantly improved over time. However, there were no significant differences between groups at any timepoint. Radiographic parameters were not different between groups. There were no significant differences in functional outcomes, radiographic parameters, and complications between early and delayed mobilization after volar fixed-angle plate of DRF. Immediate postoperative wrist range-of-motion exercise can be safely initiated after volar fixed-angle plate fixation of DRF without external immobilization.Clinical trial registration: Thaiclinicaltrials.org identifier: TCTR20180927005. Registered 27/09/2018-retrospectively registered. https://www.thaiclinicaltrials.org/show/TCTR20180927005 .

Reliability of capillary refill time for evaluation of tissue perfusion in simulated vascular occluded limbs.

PURPOSE: No standardized execution or evidence demonstrates the area of the digit giving the most accurate capillary refill time (CRT). This study investigated the reliability and validity of CRT, and the relative merits of areas where the test could be performed. METHODS: In all, 127 healthy volunteers were assessed for normal CRT at the fingernail, lateral paronychia, and proximal and distal pulps of the index finger. The predictive validity of the CRT for the diagnosis of compromised vascular perfusion was also investigated on 24 subjects, using an inflated tourniquet. Three raters assessed interobserver reliability. RESULTS: The mean fingernail, lateral paronychia, proximal pulp, and distal pulp CRTs were 1.93, 1.78, 1.70, and 1.57 s, respectively. The tourniquet and non-tourniquet results demonstrated significant mean differences; however, the fingernail showed a subtle difference (1.22 s) compared with the proximal pulp (4.46 s). The CRT interobserver reliability was fair at the fingernail (intraclass correlation coefficient [ICC] = 0.51), but very poor in occluded limbs (ICC = 0.13). At the lateral paronychia and finger pulp, the interobserver reliability was reasonable (ICC = 0.75-0.81 [non-tourniquet] vs 0.62-0.68 [tourniquet]). In a receiver-operating characteristic curve analysis, the proximal pulp demonstrated better discrimination (area under the curve = 0.93, 95% CI 0.89-0.97, p < 0.0001); the best cutoff point was calculated to be 3 s at the proximal pulp. CONCLUSIONS: CRT use at appropriate areas is reliable. The most dependable site is the finger pulp, and the proposed cutoff is 3 s.

Topical anaesthesia as an adjuvant to local anaesthetic injection in open trigger digit release: a randomized controlled trial.

We conducted a randomized controlled trial to compare pain scores and patient satisfaction between topical anaesthetic cream (5% lidocaine-prilocaine cream) versus placebo cream, applied approximately 90 minutes before local anaesthetic injection for open trigger digit release. One hundred participants were enrolled and randomly allocated into the two groups between May 2019 and February 2020. The visual analogue pain scores and satisfaction scores were measured. Most participants were female with Quinnell Grade 2-3 trigger digits. The pain scores during needle injection, local anaesthetic infiltration, the overall pain and satisfaction scores had no statistically significant differences between groups. There was no correlation between duration of topical anaesthetic drug application and pain scores. Subgroup analysis did not show significant differences in pain scores between genders. No complications were found during the study period. The topical anaesthetic drug was ineffective to use on the palmar skin during open trigger digit release surgery.Level of evidence: II.

Cost-saving Minimal Incision Endoscopic-assisted Cubital Tunnel Release Using Simple Surgical Instruments: Case Series.

Cubital tunnel syndrome (CuTS) is a well-recognized compressive neuropathy worldwide. With technological advancement, endoscopy is introduced to facilitate the procedure. However, there are concerns about the excessive cost that comes with special instruments. This article aims to provide the results of the cost-saving endoscopic-assisted cubital tunnel release surgical technique that uses the normally available operating instruments. A retrospective review was performed of the nine patients that were diagnosed with CuTS and underwent minimal incision endoscopic-assisted cubital tunnel release in Police General Hospital. Patients were followed up to sixth month postoperation. The modified McGowan classification was used to determine the severity of symptoms. Surgical outcomes were evaluated by the modified Bishop classification, visual analog score (VAS), and patients' satisfaction. Other factors investigated were scar pain and peri-incisional numbness and hematomas. The incisions were measured as 7-9 mm. All patients reported having a pain score of 1 on the third day. Seven of nine patients were able to return to work one day after surgery. Modified Bishop score showed five excellence, three good, and one fair after two weeks. There was no surgical-related complication found. All patients noted the excellence satisfaction of the procedure. The minimal incision endoscopic-assisted cubital tunnel release has shown favorable outcomes with the cost-saving of simple instruments. However, a large prospective trial may be needed for further study.

Is Pseudomeningocele an Absolute Sign of Root Avulsion Brachial Plexus Injury?

BACKGROUND: The finding of pseudomeningocele from cervical myelogram is widely accepted as a pathognomonic sign for diagnosing root avulsion in brachial plexus injury. In general, motor power in this setting should be absent. However, in clinical practice, we observed that motor power in some patients was still preserved. The objective of this study is to evaluate the accuracy of pseudomeningocele from cervical myelogram for predicting root avulsion in brachial plexus injury. METHODS: We retrospectively reviewed 201 patients with brachial plexus injury from 2007-2011. Four patients were excluded due to open wound injury. Motor power of the key muscle of each nerve root was evaluated by skilled hand surgeons. All cervical myelogram was interpreted by radiologists. Sensitivities, specificities, positive predictive values and negative predictive values were calculated with 95% confidence interval. RESULTS: Thirty and 29% of pseudomeningocele occurred at C7 and C8 level, respectively. The sensitivity of pseudomeningocele of each root from C5 to T1 was low (range, 10-62%). The specificity was high only at C5 (91%) and T1 (96.2%). Over 20% of patients with pseudomeningocele at C6-8 levels had some motor function. The initial muscle power of these patients was M1 or M2 and 70% of them recovered to at least M3 at the final follow-up. CONCLUSIONS: Pseudomeningocele is not an absolute sign for diagnosing of root avulsion in brachial plexus injury due to its high false positive rate when compared with preoperative motor function of each root. Careful examination of the key muscle of each root is extremely crucial to prevent unnecessary operation on that cervical nerve root.

Midterm outcome of partial radial head replacement with a contoured iliac crest bone graft in complex elbow dislocation.

PURPOSE: To report the midterm outcome of a novel reconstructive technique using a contoured iliac crest bone graft for partial radial head replacement in the treatment of complex elbow dislocation. MATERIAL AND METHODS: Between January 2008 and December 2013, 10 patients (5 women, 5 men; mean age, 43.8 years; mean follow-up duration, 65.9 months) with complex elbow dislocation who underwent the partial radial head replacement with the contoured bone graft were included in the study. The irreparable radial head defects averaged 49% of the articular surface (range, 36-60%). The fracture involved the entire head in four patients and partial head in six patients. RESULTS: At the final follow-up, the mean elbow extension was 8°, flexion 143°, supination 76.5°, and pronation 73°. The mean Mayo elbow performance index was 93.2 points and the Broberg-Morrey functional rating score was 94.1 points, with seven excellent cases, two good cases, and one fair case. Radiographic union was achieved in all but one, at an average time of 6.89 weeks (range, 6-10 weeks). The final radiographs demonstrated no evidence of degenerative change in eight patients, mild arthritis in one patient, and moderate arthritis in one patient. CONCLUSION: This technique is a viable option in the treatment of the large radial head defect in complex elbow dislocation when more than 40% of the original head is still available for incorporation.

End-to-Side Neurorrhaphy to Restore Elbow Flexion in Brachial Plexus Injury.

Background: End-to-side (ETS) neurorrhaphy is a controversial technique that is used for nerve transfer to achieve functional recovery. The advantage of this technique is the safety of donor nerve function. In this study, patients with extended upper-arm brachial plexus injury and significant hand weakness that did not meet the clinical criteria for end-to-end nerve transfer (Oberlin transfer) were treated by ETS neurorrhaphy to achieve biceps muscle reinnervation. Objective: To evaluate the outcome of ETS for biceps muscle reinnervation in brachial plexus injury patients. Material and Method: Thirteen patients with complete upper-arm and incomplete lower-arm brachial plexus injuries were treated by ETS of the motor branch of the biceps muscle to the ulnar or median nerves using the epineurial window technique. Results: Motor recovery was observed in nine of 13 patients. Good results were achieved in six patients who attained biceps motor power ≥ M3. No additional neurological deficits of the ulnar or median nerves were identified after the surgery. Conclusion: End-to-side neurorrhaphy is a viable treatment option for restoration of biceps muscle function if conventional end-to-end nerve transfer cannot be performed.

Neuropathic pain in brachial plexus injury.

BACKGROUND: In Thailand, brachial plexus injury is a common traumatic injury that affects the function of the upper extremity. The current treatments focus mainly on improving the motor and sensory function. Apart from the motor and sensory deficit, these patients usually suffer from pain. OBJECTIVE: The purpose of this study was to determine the prevalence and factors that relate to neuropathic pain in patients with brachial plexus injury. METHODS: We collected data from March 2008 to July 2011. The DN4 Questionnaire was used to diagnose neuropathic pain in 95 patients. RESULTS: The prevalence of neuropathic pain was as high as 76%. Majority of patients presented with hypoesthesia to pin prick, hypoesthesia to touch and numbness. Severity of neuropathic pain was significantly correlated with the type of brachial plexus injury. There was no difference between demographic characteristics of patients. CONCLUSION: Our study showed that the prevalence of neuropathic pain was high in brachial plexus injured patients. Therefore, surgeons should be aware of this common, yet underestimated, problem in brachial plexus injured patients.

Effectiveness and safety of home-based muscle electrical stimulator in brachial plexus injury patients.

OBJECTIVE: To evaluate the effectiveness and safety of home-based muscle electrical stimulation system in brachial plexus injury patients. MATERIAL AND METHOD: Forty brachial plexus injury patients underwent muscle electrical stimulation using a custom designed electrical stimulator. Effectiveness of the system, visual analog pain score, skin temperature, superficial skin condition, overallpatient satisfaction, and location of treatment preference were evaluated after the intervention. A follow-up telephone call was used to evaluate late-onset complications. RESULTS: Thirty-three men and seven women with an average age of 32 years were enrolled in the present study. According to our predefined definitions, 39 of 40 stimulation sessions were successfully completed, which resulted in a total system effectiveness of 97.5%. All patients tolerated the stimulation well. The average visual analog pain score was significantly decreased from 4 to 3 after the stimulation. There were no adverse incidents reported. The average patient satisfaction score was 7.8 out of 10. Thirty-five of 40 patients (88%) preferred to use home-based electrical stimulation vs. hospital-based treatment. CONCLUSION: The custom designed muscle electrical stimulator used in this study has demonstrated adequate effectiveness and safety for clinical home use for brachial plexus injury patients.

An experimental study to determine and correlate choline acetyltransferase assay with functional muscle testing after nerve injury.

OBJECT Choline acetyltransferase (ChAT) is an enzyme synthesized within the body of a motor neuron whose role is to form the neurotransmitter acetylcholine. Quantification of ChAT levels in motor or mixed nerves has been proposed to provide information regarding the viability of a proximal nerve stump for motor neurotization following brachial plexus injury. To do so requires information regarding normal ChAT levels and those in injured nerves, as well as the correlation of ChAT level determined at surgery with eventual motor recovery. The purpose of this study was to determine ChAT activity in the normal and injured sciatic/peroneal nerve in a rat model, evaluate the correlation between ChAT and motor recovery, find the relationship between ChAT activity and isometric muscle force, and elucidate the parallel between ChAT activity and acetylcholinesterase (AChE) activity. METHODS Sixty animals were divided into 3 groups. The sciatic nerves in Group 1 were transected without repair. Nerves in Group 2 were transected and repaired. Nerves in Group 3 sustained a crush injury followed by transection and reconstruction. All animals were allowed 12 weeks of recovery followed by evaluation of ChAT levels in the peroneal nerve, correlated with measures of maximal isometric tibialis anterior muscle force and muscle weight (the operated side normalized to the control side). Karnovsky AChE staining of peroneal nerve segments was also compared with radiochemical assay of ChAT activity in the same nerve. RESULTS A significant difference in the tibialis anterior isometric tetanic force and the tibialis anterior muscle weight index (TAMI) was noted between Group 1 and Groups 2 and 3 (p < 0.0001); no significant difference was found comparing Group 2 with Group 3. The correlation between the force measurement and the TAMI was 0.382. Both AChE measurement and ChAT activity demonstrated significantly fewer fibers in the operated nerve compared with the contralateral nerve. Intergroup variability could also be illustrated using these tests. The correlation coefficient between the isometric tetanic force measurement and the ChAT analysis in Groups 1 and 2 was 0.468. The correlation for the AChE staining and the isometric tetanic force measurement was 0.111. The correlation between the TAMI and the ChAT levels was 0.773. The correlation between the TAMI and the AChE-stained fibers was 0.640. Correlating AChE staining to the ChAT analysis produced a correlation of 0.712. CONCLUSIONS The great variability in all groups and weak correlations to the functional muscle assessments and the ChAT radiochemical assay made this technique an unreliable method of determining motor nerve viability.

Diaphragmatic height index: new diagnostic test for phrenic nerve dysfunction.

OBJECT: The diaphragmatic height index (DHI) was developed to measure the difference in diaphragm levels. The purpose of this study was to set definite DHI values and test the accuracy of these values for use as a new diagnostic test for phrenic nerve dysfunction. METHODS: All data for this study were obtained from medical charts and retrospectively reviewed. RESULTS: One hundred sixty-five patients with brachial plexus injury who had undergone nerve transfers between 2005 and 2008 were divided into Groups A and B. Group A consisted of 40 patients (mean age 28.0 years) who had sustained concomitant injury of the brachial plexus and phrenic nerves. Patients in Group A1 had right phrenic nerve injury and those in Group A2 had left phrenic nerve injury. Intraoperative direct electrical stimulation of the phrenic nerve was considered the gold standard in assessing nerve function in all patients with brachial plexus injury. Group B consisted of 125 patients (mean age 28.7 years) with brachial plexus injury and normal phrenic nerve function. Group C, the control group, consisted of 80 patients with nonbrachial plexus injury (mean age 34.0 years) who had undergone other kinds of orthopedic operations between April and June 2009. Standard posteroanterior chest radiographs were blindly interpreted using the Siriraj inhouse picture archiving and communication system in all 245 patients in the study. First, a reference line (R line) was drawn along the inferior endplate of T-10. Then, 2 lines (lines A and B) were drawn through the highest point of each diaphragm and parallel to the R line. The difference between these 2 lines divided by the height of T-10 was defined as the DHI. The cutoff points of the DHI for diagnosing right and left phrenic nerve dysfunction were analyzed with a receiver operating characteristic curve. The accuracy of these DHI values was then evaluated. The DHI in Group C was 0.64 ± 0.44, slightly higher than the DHI in Group B, with no significant difference. Diaphragmatic height indexes in Groups A1 and A2 were 2.0 ± 0.99 and -1.04 ± 0.83, respectively, which were significantly different from those in Groups B and C (p < 0.05). The cutoff point of the DHI for diagnosing right phrenic nerve dysfunction was > 1.1, and that for left phrenic nerve dysfunction was < 0.2. The sensitivity and specificity of right and left DHI values were 90.5% and 86.3%, and 94.7 and 88.3%, respectively. CONCLUSIONS: Data in this study show that diaphragm paralysis can be simply and reliably predicted by the DHI. Diaphragmatic height index values > 1.1 and < 0.2 are proposed as the new diagnostic test for right and left phrenic nerve dysfunction with a high degree of accuracy. This index is applicable in diagnosing phrenic nerve dysfunction that occurs concomitantly with brachial plexus injury or from other etiologies.

Long-term results of cemented metal-backed glenoid components for osteoarthritis of the shoulder.

BACKGROUND: There has been recent renewed interest in the use of metal-backed glenoid components in total shoulder arthroplasty. However, little information is available on the long-term results. The purpose of this study was to determine the results, the risk factors for an unsatisfactory outcome, and the failure rates of total shoulder arthroplasty with a cemented metal-backed glenoid component. METHODS: Between 1985 and 1991, 100 total shoulder arthroplasties with Neer cemented metal-backed glenoid components were performed at our institution to treat osteoarthritis. Ninety-five shoulders were followed for a minimum of two years (mean, 10.8 years) or until the time of revision surgery. Patients were assessed with use of a modified Neer rating system at the time of the latest follow-up. Radiographs of eighty-three shoulders were assessed for the presence of glenoid erosion, glenohumeral subluxation, periprosthetic lucency, and a shift in component position. RESULTS: Total shoulder arthroplasty with a cemented metal-backed glenoid component was significantly associated with pain relief (p < 0.001) as well as with an improvement in abduction from a mean of 92 degrees to 146 degrees (p < 0.001) and external rotation from a mean of 26 degrees to 60 degrees (p < 0.001). According to the modified Neer result-rating system, the result was excellent in forty-seven shoulders, satisfactory in twenty-seven shoulders, and unsatisfactory in twenty-one shoulders. Five patients underwent revision surgery because of component loosening (two patients), component subluxation (one patient), a fracture distal to the stem (one patient), and polyethylene wear (one patient). Glenoid periprosthetic lucency was present in sixty-nine (83%) of eighty-three shoulders at a minimum radiographic follow-up of two years. CONCLUSIONS: The data from this study suggest that total shoulder arthroplasty with a cemented metal-backed glenoid component for the treatment of osteoarthritis is associated with pain relief and improvement in motion. However, the high rate of glenoid periprosthetic lucency is concerning and requires additional follow-up and investigation. These results are not better than those that have been reported for all-polyethylene cemented glenoid components.

Isometric tetanic force measurement method of the tibialis anterior in the rat.

Tetanic force measurements of rat tibialis anterior (TA) muscles have been described, but with a variety of stimulation parameters. This study presents a novel functional method of force measurement of the rat TA muscle and describes the optimization of stimulation parameters. Bilateral TA muscles in 10 male Lewis rats were attached to a force transducer after the corresponding hindlimb was fixed. Preload, stimulus intensity, duration, and frequency were optimized for each individual muscle and the isometric maximal tetanic muscle force was measured. The mean left side tetanic force as a percentage of the right was 100.0 +/- 4.4% and was statistically equivalent. Large standard deviations between sides (35-50%) were observed in the optimized parameters (preload, stimulus intensity, duration, and frequency). Optimization of the variables affecting isometric tetanic force resulted in reproducible and reliable side-to-side measurements of the TA muscle in the rat model.

An anatomic study of the spinal accessory nerve: extended harvest permits direct nerve transfer to distal plexus targets.

An anatomic study of the distal spinal accessory nerve (SAN) to determine the number of myelinated axons and feasibility of posterior harvest for direct neurotization of distal targets was performed. Ten fresh human cadavers were studied. A supraclavicular approach was performed followed by a posterior approach. The relationship of the SAN to bony landmarks (T1 spinous process, acromioclavicular joint, posterolateral corner of the acromium, and angle at the superior medial border of the scapula) as well as maximal harvestable length was recorded. After posterior dissection, the SAN was mobilized and the ability to reach both anterior infraclavicular and posterior targets was assessed. Axon counts were also performed at the proximal, mid, and distal points along the course of the nerve. The posteriorly harvested SAN was identified reliably with respect to bony landmarks. When harvested posteriorly, the SAN could reach the infraclavicular part of the brachial plexus (i.e., terminal branches), and posteriorly, the suprascapular nerve (SSN) both proximal and distal to the suprascapular ligament, the latter for selective reinnervation of the infraspinatus branch. The average number of myelinated fibers at the proximal end of the nerve was 1,328 axons, at the mid-way point was 1,021 axons, and at terminal end of the nerve was 817 axons. Harvest of the SAN from a posterior approach based on these landmarks is feasible, allowing direct transfer of the nerve to the infraclavicular brachial plexus and to the SSN both proximal and distal to the suprascapular ligament, without the use of interposition nerve grafts.

Intraobserver and interobserver reliability of two ultrasound measures of humeral head position in infants with neonatal brachial plexus palsy.

BACKGROUND: Ultrasonographic evaluation of the hip in infants is considered both reliable and reproducible in the diagnosis of developmental dysplasia of the hip. Ultrasonographic evaluation of the shoulder in infants has been reported as a valuable diagnostic aid in dysplastic development following neonatal brachial plexus palsy. To our knowledge, there has been no study of the intraobserver reproducibility and interobserver reliability of sonography of the shoulder in infants with and without suspected posterior shoulder dislocation. METHODS: Two identical but randomly ordered sets of the same deidentified sonographic images of shoulders in infants were given to radiologists, pediatric orthopaedists and orthopaedic residents, and fellows with varying degrees of experience in the evaluation of shoulder pathology in infants, who measured the position of the humeral head relative to the axis of the scapula. Intraobserver reproducibility and interobserver reliability of the measurements were assessed. RESULTS: For the position of the humeral head with respect to the glenoid in both normal and abnormal conditions, the Pearson correlation coefficient for intraobserver reproducibility was 0.91 and the intraclass correlation coefficient for interobserver reliability was 0.875. For estimating the percentage of the humeral head posterior to the axis of the scapula, the Pearson correlation was 0.85 and the intraclass correlation coefficient was 0.77. CONCLUSIONS: Ultrasonographic examination of the shoulder in infants to assess for the position of the humeral head with respect to the scapula showed high intraobserver reproducibility and interobserver reliability. It is recommended as a reliable technique for evaluating shoulder position in infants with neonatal brachial plexus palsy.