Structural bone grafting for glenoid deficiency in primary total shoulder arthroplasty.

BACKGROUND: Glenoid bone grafting can be useful to restore an asymmetrically eroded glenoid to better support the glenoid component and improve positioning. The purpose of this study was to evaluate the clinical and radiographic results of patients undergoing structural bone grafting for glenoid deficiency with placement of a cemented glenoid component during primary total shoulder arthroplasty. METHODS: Between January 1, 1976, and December 31, 2008, 24 patients (25 shoulders) of 2607 shoulders undergoing primary total shoulder arthroplasty (0.96%) had structural bone grafting with a humeral head autograft and screw fixation. The mean clinical follow-up was 8.7 years, and the mean radiographic follow-up was 7.6 years. RESULTS: Twenty-three shoulders experienced pain relief, and patients expressed satisfaction with the operation in these shoulders. Postoperative active elevation averaged 148°, and external rotation with the arm at the side averaged 60°. On radiographic evaluation, 10 shoulders had glenoids at risk for component loosening. Two of these shoulders were symptomatic and underwent revision surgery to address glenoid component loosening. The Neer result rating was excellent in 18 shoulders, satisfactory in 5, and unsatisfactory in the 2 shoulders undergoing revision. CONCLUSION: Structural bone grafting in primary total shoulder arthroplasty is uncommonly necessary. When it is performed, the clinical outcomes are favorable; however, radiographic analysis shows a moderate rate of failure of glenoid component fixation. It seems likely that alternative treatment methods may prove to be more effective in addressing glenoid wear.

Posterior branch of the axillary nerve transfer to the lateral triceps branch for restoration of elbow extension: case report.

We report a nerve transfer to the triceps using the posterior branch of the axillary nerve to restore elbow extension in an 18-year-old woman with a C7-T1 injury. Elbow extension strength improved from M0 to M4, whereas deltoid strength was minimally affected. Her Disabilities of the Arm, Shoulder and Hand score improved 14 points. This method may be considered for restoring triceps function in lower pattern brachial plexus injury.

Radiographic survival in total shoulder arthroplasty.

BACKGROUND: Glenoid component loosening is thought to be a major cause of failure. This study assesses radiographic and clinical failure in shoulder arthroplasty, identifying factors predictive of loosening. METHODS: Three-hundred two shoulder arthroplasties were implanted utilizing a cemented, keeled glenoid component, mean clinical follow-up 8.6 years. One-hundred fifty one shoulders had preoperative, early postoperative, and most recent radiographs, mean radiographic follow-up 8.0 years, minimum 4 years or less if revision was performed (2 cases). RESULTS: Fifty-two of 151 glenoid components (34%) showed a shift in position or a complete lucent line ≥1.5 mm. Four humeral components (3%) shifted or showed a 2-mm lucency in 3 zones. Component survival (Kaplan-Meier) free from radiographic failure at 5 and 10 years were 99% (95% CI) (98-100%) and 67% (95% CI) (58-78%). Glenoid components with lines at the keel on initial radiographs were at risk for radiographic failure, hazard ratio 4.6 95% CI 1.2-17.2, P = .02. No associations were found between radiographic survival and age, gender, diagnosis, glenoid erosion, and preoperative or early subluxation. Late subluxation superiorly was associated with the glenoid at risk for radiographic failure (P = .006). Glenoid component survivals free from revision at 5 and 10 years for the 302 shoulders were 99% (95% CI) (97-100%) and 93% (95% CI) (90-97%). CONCLUSION: Glenoid radiolucencies are seldom seen early, except beneath the faceplate. Glenoid radiolucencies develop, with notable changes 5 or more years following surgery. Humeral components seldom loosen. Revision rates remain low. The high frequency of late radiographic changes dictates the need for innovation.

Feed-forward excitation of striatal neuron activity by frontal cortical activation of nitric oxide signaling in vivo.

The gaseous neurotransmitter nitric oxide plays an important role in the modulation of corticostriatal synaptic transmission. This study examined the impact of frontal cortex stimulation on striatal nitric oxide efflux and neuron activity in urethane-anesthetized rats using amperometric microsensor and single-unit extracellular recordings, respectively. Systemic administration of the neuronal nitric oxide synthase inhibitor 7-nitroindazole decreased spontaneous spike activity without affecting activity evoked by single-pulse stimulation of the ipsilateral cortex. Train (30 Hz) stimulation of the contralateral frontal cortex transiently increased nitric oxide efflux in a robust and reproducible manner. Evoked nitric oxide efflux was attenuated by systemic administration of 7-nitroindazole and the non-selective nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester. Train stimulation of the contralateral cortex, in a manner identical to that used to evoke nitric oxide efflux, had variable effects on spike activity assessed during the train stimulation trial, but induced a short-term depression of cortically evoked activity in the first post-train stimulation trial. Interestingly, 7-nitroindazole potently decreased cortically evoked activity recorded during the train stimulation trial. Moreover, the short-term depression of spike activity induced by train stimulation was enhanced following pretreatment with 7-nitroindazole and attenuated after systemic administration of the dopamine D2 receptor antagonist eticlopride. These results demonstrate that robust activation of frontal cortical afferents in the intact animal activates a powerful nitric oxide-mediated feed-forward excitation which partially offsets concurrent D2 receptor-mediated short-term inhibitory influences on striatal neuron activity. Thus, nitric oxide signaling is likely to play an important role in the integration of corticostriatal sensorimotor information in striatal networks.

Anatomic shoulder arthroplasty as treatment for locked posterior dislocation of the shoulder.

BACKGROUND: Chronic locked shoulder dislocations account for 2% to 5% of all shoulder dislocations. There is little information regarding the mid-term to long-term results of anatomic shoulder arthroplasty for treatment of this problem. METHODS: Thirty-two shoulder arthroplasties were performed in thirty-two patients who had chronic locked posterior dislocation of the shoulder. Eighteen patients were treated with a hemiarthroplasty and fourteen, with a total shoulder arthroplasty. Inclusion criteria included moderate or severe pain and functional limitations. Structural indications included an impression fracture involving ≥45% of the humeral head, fibrosis of the articular cartilage, and/or severe osteopenia of the humeral head. When one-third or more of the glenoid was devoid of articular cartilage, a glenoid component was placed. All patients were followed for a minimum of two years (mean, 8.2 years) or until a reoperation. RESULTS: The operations led to pain relief, with the median pain score decreasing from 4 (on a 5-point scale) preoperatively to 3 postoperatively (p < 0.01), and improvement in shoulder external rotation, from a preoperative median of -15° to a postoperative median of 50° (p < 0.001). Instability recurred in three patients in the early postoperative period. Nine patients underwent a reoperation for various reasons. According to a modified Neer rating system, there were four excellent, fifteen satisfactory, and thirteen unsatisfactory outcomes. CONCLUSIONS: Although shoulder arthroplasty for locked posterior dislocation can provide pain relief, improved shoulder external rotation, and a low risk of recurrent instability, the overall rate of satisfaction is inferior to that following anatomic arthroplasty for treatment of glenohumeral osteoarthritis.