Sung-Weon Jung

Factors that Influence Reduction Loss in Proximal Humerus Fracture Surgery.

Objectives: This study was performed to identify the risk factors for reduction loss after locking plate fixation of proximal humerus fractures. Design: Retrospective study. Setting: University trauma center. Patients and Intervention: We retrospectively evaluated 252 patients who had been surgically treated for proximal humeral fractures with locking plates between January 2004 and December 2011. Main Outcome Measurements: Charts and standardized x-rays (true anteroposterior and axillary lateral views) were used to evaluate the Neer and AO OTA fracture types, initial neck-shaft angle (NSA, varus displacement), medial comminution, postoperative NSA (reduction adequacy), medial support restoration, healing progress, reduction loss, and implant-related problems immediately after surgery and at 2 weeks, 1 month, 3 months, 6 months, 9 months, and at least 1 year after surgery. Reduction loss was defined as (1) ≥10 of angulation in any direction, (2) ≥5 mm of height loss of the humeral head from the plate, and (3) fixation failure. Results: Reduction loss occurred in 6.7% (17 of 252) of cases; revision surgeries were performed in all cases. Univariable logistic regression analysis revealed that older age (P = 0.023), osteoporosis (P = 0.001), varus displacement (P = 0.001), medial comminution (P = 0.001), reduction adequacy (P = 0.036), and insufficient medial support (P = 0.001) had significant correlations with reduction loss. Conclusions: Multivariable regression analysis revealed that osteoporosis (less than −2.5 bone mineral density, P = 0.015), displaced varus fracture (less than 110° of NSA, P = 0.025), medial comminution (more than 1 fragment, P = 0.018), and insufficient medial support (no cortical or screw support, P = 0.001) were independent risk factors for reduction loss in the proximal humerus fractures surgery. Level of Evidence: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Indirect Reduction Maneuver and Minimally Invasive Approach for Displaced Proximal Humerus Fractures in Elderly Patients

Background This study examined the clinical outcomes of indirect reduction maneuver and minimally invasive approach for treating displaced proximal humerus fractures in patients older than 60. Methods Thirty-two patients (11 male and 21 female) who had undergone treatment for displaced proximal humerus fracture were evaluated. The mean age of the patients was 72.4 years (range, 60 to 92 years). All cases were followed up for at least 12 months. All patients were interviewed and evaluated on the visual analog scale, with gender-specific constant score correction for age, standardized X-rays to check the neck-shaft angle (NSA) and the presence of medial support, and bone mineral density. Statistical analysis was performed with a multiple regression analysis. Results The average visual analog scale score was 2.4, and the average gender-specific constant score correction for age was 80.6 points. Final functional outcomes were 8 excellent, 15 good, 7 fair, and 2 poor. The average NSA was 122.8°; and the radiological results were 20 good, 11 fair, and 1 poor. There was significant difference of the gender-specific constant score for age between the group of NSA more than 110° and the group of NSA less than 110° (p = 0.00). There were 26 cases with and 6 cases without medial support, with significant difference between the gender-specific constant score correction for age of these groups (p = 0.01). Complications occurred in 4 patients (12.5%). Conclusions The indirect reduction maneuver and minimally invasive approach were safe and reliable options for the treatment of displaced proximal humerus fractures in the elderly patients. An inadequate reduction (i.e., less than 110° NSA) or lack of medial support (e.g., no cortical or screw support) were significant factors contributing to poor functional outcomes.

Standard versus over-tensioning in the transfer of extensor indicis proprius to extensor pollicis longus for chronic rupture of the thumb extensor

PURPOSE The purpose of this study was to evaluate the functional outcomes of the over-tensioning technique compared with those of the standard tensioning technique in the transfer of extensor indicis proprius (EIP) to extensor pollicis longus (EPL) for the chronic rupture of the thumb extensor. METHODS Data were collected from patients who underwent tendon transfer using EIP between March 2003 and August 2011. 23 were treated with the standard tensioning technique and 25 patients (Group B) with the over-tensioning technique. While standard tension was maintained with the thumb in full extension and the wrist in 30° of flexion, over-tension was maintained with the thumb in full extension and the wrist in the neutral position. All patients were assessed for total range of motion, elevation and flexion deficit, the thumb grip and pinch strength, and the thumb and the index extension strength compared to the unaffected side, EIP-EPL evaluation as suggested by Lemmen et al. and Disabilities of the Arm, Shoulder, and Hand questionnaire (DASH). RESULTS Group A: total range of motion 115°, elevation deficit 2.0 cm, combined flexion deficit 1.0 cm, thumb extension strength 75%, thumb grip strength 91%, and pinch strength 87%. Functional outcomes were 13 excellent, 6 good, 3 fair, and 1 poor. Median DASH score was 21.3 points. Group B: total range of motion 125°, elevation deficit 1.0 cm, combined flexion deficit 1.5 cm, thumb extension strength 85%, thumb grip strength 88%, and pinch strength 83%. Functional outcomes were 16 excellent, 7 good, 2 fair, and 0 poor. Median DASH score was 19.8 points. There are significant differences in the range of motion, elevation deficit, and extension strength of thumb between the two groups (p=.001, p=.001, and p=.028, respectively). CONCLUSION While the functional outcomes of both groups were favorably acceptable in a majority of the patients, there were significant differences in aspects of range of motion, elevation deficit, and strength of the thumb between both groups. LEVEL OF EVIDENCE Case-control study, Level III.

In vivo biomechanical measurement and haptic simulation of portal placement procedure in shoulder arthroscopic surgery

A survey of 67 experienced orthopedic surgeons indicated that precise portal placement was the most important skill in arthroscopic surgery. However, none of the currently available virtual reality simulators include simulation / training in portal placement, including haptic feedback of the necessary puncture force. This study aimed to: (1) measure the in vivo force and stiffness during a portal placement procedure in an actual operating room and (2) implement active haptic simulation of a portal placement procedure using the measured in vivo data. We measured the force required for port placement and the stiffness of the joint capsule during portal placement procedures performed by an experienced arthroscopic surgeon. Based on the acquired mechanical property values, we developed a cable-driven active haptic simulator designed to train the portal placement skill and evaluated the validity of the simulated haptics. Ten patients diagnosed with rotator cuff tears were enrolled in this experiment. The maximum peak force and joint capsule stiffness during posterior portal placement procedures were 66.46 (±10.76N) and 2560.82(±252.92) N/m, respectively. We then designed an active haptic simulator using the acquired data. Our cable-driven mechanism structure had a friction force of 3.763 ± 0.341 N, less than 6% of the mean puncture force. Simulator performance was evaluated by comparing the target stiffness and force with the stiffness and force reproduced by the device. R-squared values were 0.998 for puncture force replication and 0.902 for stiffness replication, indicating that the in vivo data can be used to implement a realistic haptic simulator.