Screw inserting in different phase of cement affect the pull-out strength of cement augmented screws.

BACKGROUND: For large bone defects, after curettage of aggressive bone tumors; such as giant-cell tumors, cementation with supplement internal fixation was used to prevent subsequent collapse of the cement-bone constructs. The purpose of this study is to compare the pull-out strength of cement augmented screws between inserting screws in the working phase or hard phase of bone cement. HYPOTHESIS: Timing at which completed screw insertion takes place affecting the pull-out strength of cement augmented screws. METHODS: Pull-out strength was compared between screws; inserted within the working phases of cement, and after the cement was hardened in high viscos cement blocks. Each group consists of 10 cortex screws, 10 cancellous screws and 10 locking screws. The pull-out strength test was followed using the instructions of ASTM F543-13e1 Standard Specification and Test Methods, for Metallic Medical Bone Screws. RESULTS: Screws that were inserted in the working phases of cement had significantly higher pull-out strength, than those inserted in hard cement (p=0.021). The pull-out strength was statistically significant in difference among the types of screws (p<0.001), with locking screws having the highest pull-out strength. Furthermore, the pull-out strength of locking screws revealed no significant difference when either; inserted during the working or hardened phases of bone cement. CONCLUSION: Insertion of screws during the working periods of PMMA cement had higher pull out strength compared to the hard phase of cement. Hence, we recommend performing internal fixation before cementation after curettage of aggressive bone tumors. However, if the surgeon prefers to pack the cement first, for the benefit of avoiding residual bone defects, we suggest using a locking plate system to achieve comparable pull-out strength. LEVEL OF EVIDENCE: In-vitro study.

Comparing the running subcuticular technique versus the Donati technique in open carpal tunnel release: a randomized controlled trial.

BACKGROUND: There are various skin suture techniques for wound closure following carpal tunnel release, and well-performed suturing will result in low post-operative scar tenderness. The aim of this study was to compare the Donati suture technique and running subcuticular technique in terms of surgical scar, post-operative pain and functional outcome in open carpal tunnel release. METHODS: One-hundred forty-two patients were randomized using a computer-generated random number table into two groups receiving either running subcuticular suturing or Donati suturing after surgical intervention. We evaluated postoperative scarring using the Patient and Observer Scar Assessment Scale (POSAS), pain intensity using a verbal numerical rating scale, and functional outcomes using the Thai version of the Boston Carpal Tunnel Questionnaire after surgical decompression for carpal tunnel syndrome at 2, 6, and 12 weeks. Continuous data are reported as mean ± SD while normally distributed or as median (interquartile range) when the distribution was skewed. RESULTS: Lower scores at 2 weeks were given by the patients receiving the running subcuticular suture technique than the Donati suture technique (15.3 ± 4.8 vs 17 ± 4.6, respectively, P < 0.05) while the observer scores were not significantly different (15.6 ± 5.8 vs 16.7 ± 5.2, respectively, P = 0.15). At both 6 and 12 weeks post-surgical decompression both patient and observer scores were not significantly different. There were no differences between the groups in terms of VNRS pain scores and functional Boston Carpal Tunnel Scores at all time points. CONCLUSIONS: This randomized controlled trial found that although scarring assessments were slightly better in the earliest period following wound closure after surgical decompression in carpal tunnel syndrome using the running subcuticular suture, the final results at 3 months postoperative were not significantly different. TRIAL REGISTRATION: The study was registered at https://www.thaiclinicaltrials.org/ (TCTR20191204002).

Location of the radial nerve along the humeral shaft between the prone and lateral decubitus positions at different elbow positions.

Identification of the radial nerve is important during the posterior approach to a humerus fracture. During this procedure, the patient can be placed in the prone or lateral decubitus position depending on the surgeon's preference. The distance from the radial nerve to the osseous structures will be different in each position. The purpose of this study was to identify the safety zones in various patient and elbow flexion positions. The distances from the olecranon to the center of the radial groove and intermuscular septum and lateral epicondyle to the lateral intermuscular septum were measured using a digital Vernier caliper. The measurements were performed with cadavers in the lateral decubitus and prone positions at different elbow flexion angles. The distance from where the radial nerve crossed the posterior aspect of the humerus measured from the upper part of the olecranon to the center of the radial nerve in both positions at different elbow flexion angles varied from a mean maximum distance of 130.00 mm with the elbow in full extension in the prone position to a minimum distance of 121.01 mm with the elbow in flexion at 120° in the lateral decubitus position. The mean distance of the radial nerve from the upper olecranon to the lateral intermuscular septum varied from 107.13 to 102.22 mm. The distance from the lateral epicondyle to the lateral edge of the radial nerve varied from 119.92 to 125.38 mm. There was not significant contrast in the position of the radial nerve with osseous landmarks concerning different degrees of flexion, except for 120°, which is not significant, as this flexion angle is rarely used.