Medial Meniscus Posterior Root Repair Restores Contact Pressure and Contact Area to Its Native State Even After Opening-Wedge High Tibial Osteotomy: A Cadaveric Biomechanical Study.

PURPOSE: To elucidate the effect of medial meniscus posterior root (MMPR) repair during opening-wedge high tibial osteotomy (OWHTO) in terms of contact pressure (CP) and contact area (CA). METHODS: Nine fresh-frozen human cadaveric knee specimens were included. Each specimen was tested under 9 conditions comprising 3 different degrees of correction during OWHTO (neutral, 5° of valgus, and 10° of valgus) and 3 different types of MMPR conditions (intact, torn, and repaired). The prepared specimens were attached to a customized tibiofemoral jig in a fully extended state. The CP and CA generated by a tibiofemoral axial load of 650 N was recorded using the Tekscan sensor's pressure mapping software. Statistical analysis was performed using a repeated measures analysis of variance. RESULTS: The increased CP and decreased CA in torn MMPR was decreased and increased, respectively, to the intact MMPR after repairing, irrespective of whether OWHTO was performed. The mean CP at a correction angle of 5° of valgus was 0.4067 ± 0.0768 MPa for intact MMPR, which increased to 0.7340 ± 0.1593 MPa for the torn MMPR and decreased to 0.3614 ± 0.0639 MPa for the repaired MMPR. In addition, the proportion of decrease in CP and increase in CA after MMPR repair was constant, compared with the torn MMPR, irrespective of the degree of correction during OWHTO. CONCLUSIONS: MMPR repair decreases CP and increases CA, irrespective of whether OWHTO is performed. The biomechanical advantage of repairing torn MMPR is maintained, regardless of the degree of correction during OWHTO. CLINICAL RELEVANCE: Both OWHTO and MMPR repair are known to protect the medial compartment of the knee. However, there are concerns in performing 2 procedures simultaneously. Results of our study showed that concurrent repair of the MMPR during OWHTO is useful for protecting the medial compartment of the knee with respect to tibiofemoral contact biomechanics.

The Improved Proximal Phalanx Osteotomy for Reducing Sesamoid in Hallux Valgus Surgery-A Cadaver Study.

A metatarsal osteotomy is known to have the effect of reduction of the sesamoid. However, the reduction of the sesamoid is not always completed by a metatarsal osteotomy alone. The purpose of this cadaver study was to show that the improved technique of a modified Akin proximal phalanx osteotomy (MPO) could be helpful for the reduction of the sesamoids in hallux valgus surgery. Ten feet of cadavers were used; the cadavers had hallux valgus on both feet. The first trial of two feet underwent only the MPO. The other eight feet underwent a proximal metatarsal chevron osteotomy and MPO simultaneously. The hallux valgus angle, intermetatarsal angle, Hardy's grade, and Smith's grade were measured. To predict possible complications, cadavers were dissected after surgery. In the feet that underwent an MPO only, the hallux valgus angle and sesamoid position were improved. In the feet that underwent an MPO and metatarsal osteotomy, the hallux valgus deformity was completely corrected, and the sesamoid position was improved. Overall, the hallux valgus angle and intermetatarsal angle improved from 30.6 to 8.4 degrees and from 11.2 to 4.1 degrees, respectively. The sesamoid position was reduced from 5.3 to 2.5 (Hardy) and from 1.7 to 0.7 (Smith). The MPO combined with the metatarsal osteotomy were helpful for reducing the sesamoids compared to the metatarsal osteotomy only.

Stabilization of the Distal Radioulnar Joint with or without Triangular Fibrocartilage Complex Tear by an External Wrist Band Brace: A Cadaveric Study.

The purpose of this study was to investigate whether a watch-shaped external wrist band brace improves distal radioulnar joint (DRUJ) stability. Seven fresh cadaveric arms were used. Using a customized testing system, volar and dorsal translation forces were applied to the radius externally while the ulna was fixed. The test was performed with the forearm in neutral, 60° pronated, and 60° supinated positions, once without the brace and once with the brace applied. In each condition, the amount of translation was measured. Then, the triangular fibrocartilage complex (TFCC) was detached from the ulnar styloid process and the fovea ulnaris, and the same tests were performed again. Detachment of the TFCC significantly increased volar and dorsal translations in all forearm rotations compared to the intact condition (p < 0.05), except for the pronated dorsal translation of the radius (p = 0.091). Brace application significantly reduced volar and dorsal translations in all forearm rotations both in intact specimens and in TFCC-detached specimens (p < 0.05), except for pronated volar and dorsal translations in TFCC-detached specimens (p = 0.101 and p = 0.131, respectively). With the brace applied, the TFCC-detached specimens showed no significant difference in volar or dorsal translation in all forearm rotations compared to the intact specimens (p > 0.05). The external wrist band brace improved DRUJ stability in both normal and TFCC-torn wrists and reduced the DRUJ instability caused by TFCC tear to a near-normal level.

The sex difference of the volume and surface area of the human axial skeleton.

We assessed the sex difference in the volume and surface area of the bone using three-dimensional bone models generated from computer tomography images of axial skeletal elements from 110 Korean cadavers. The volume and surface area of all bones were significantly different between females and males. The accuracy of sex determination ranged from 55.6%-93.7% in univariate discriminant function analysis, with the second thoracic vertebra showing the highest accuracy. In discriminant analysis using paired bone combinations, 22 combinations of bone volume and surface area yielded > 90% accuracy in sex determination. The highest accuracy in the stepwise analysis was 94.7% when using the surface area of the ribs, sternum, and vertebrae for determining sex. This result shows a higher or similar accuracy than previous metric and non-metric studies using the axial skeleton, however, it shows lower accuracy than previous study which used volume and surface area of the appendicular skeleton. Nevertheless, this method might have advantage that is possible to determine sex quickly due to base on the computation with medical images.

An Anatomical Study of the Palmaris Brevis, Transverse Carpal Ligament, and the Recurrent Motor Branch of the Median Nerve.

Background: The anatomical structures in relation to the carpal tunnel release are the palmaris brevis muscle (PBM), transverse carpal ligament (TCL), and the recurrent motor branch of the median nerve (RMBMN). Our aim is to describe the gross morphology in the Korean population of the PBM, TCL, and RMBMN specifically looking for anomalies, and to determine the muscles encountered during a standard carpal tunnel release. Material and Methods: A total of 30 cadaveric hands were dissected. A longitudinal line drawn from the third web space to the midpoint of the distal wrist crease served as the reference line (RL). The PBM and TCL were classified according to its shape and location. The length, width, and thickness of the TCL were measured. The ratio of the lengths of PBM and TCL to RL was calculated. The course of the RMBMN was dissected specifically looking for anomalies. We also looked at the muscle fibers encountered during a standard carpal tunnel release to identify the muscle. Results: PBM was classified into three different types based on the shape. The average thickness of the PBM and TCL were 0.89 ± 0.16 mm and 1.43 ± 0.40 mm, respectively. The distal border of the TCL was thicker than the proximal border. The average ratio of the length of the PBM to the RL was 25.65 ± 8.62% and TCL to the RL was 24.00 ± 3.37%. The distribution of the RMBMN was classified into three different types. A few accessory branches of the RMBMN were also noted. And 36 muscle fibers were noted within the TCL in line with the RL. Conclusion: We clarified findings and added quantitative information about the anatomical structures surrounding carpal tunnel. A thorough knowledge of the anatomy and anomalies around the carpal tunnel is helpful for surgeons to ensure optimal surgical results.

Morphological symmetry of the radius and ulna-Can contralateral forearm bones utilize as a reliable template for the opposite side?

The most important precondition for correction of the affected forearm using data from the contralateral side is that the left and right bone features must be similar, in order to develop patient-specific instruments (PSIs) and/or utilize computer-assisted orthopedic surgery (CAOS). The forearm has complex anatomical structure, and most people use their dominant hand more than their less dominant hand, sometimes resulting in asymmetry of the upper limbs. The aim of this study is to investigate differences of the bilateral forearm bones through a quantitative comparison of whole bone parameters including length, volume, bowing, and twisting parameters, and regional shape differences of the forearm bones. In total, 132 bilateral 3D radii and ulnae 3D models were obtained from CT images, whole bone parameters and regional shape were analyzed. Statistically significant differences in whole bone parameters were not shown. Regionally, the radius shows asymmetry in the upper section of the central part to the upper section of the distal part. The ulna shows asymmetry in the lower section of the proximal part to the lower section of the central part. Utilizing contralateral side forearm bones to correct the affected side may be feasible despite regional differences in the forearm bones of around 0.5 mm.

Safety of Retrograde Flow of Internal Mammary Vein: Cadaveric Study and Anatomical Evidence.

BACKGROUND: Additional second vessels may be required to handle multiple flaps used to add breast volume, boost blood flow for supercharging, or use salvage recipient vessels. In these situations, retrograde internal mammary vessel flow can be used although this causes doubts and concerns. PATIENTS AND METHODS: Forty sides of the chests of 20 fresh cadavers with intact thoracic cages and internal mammary veins (IMV) were used in the study. IMV valve numbers and locations were checked, and the bifurcation was confirmed. A retrograde fluorescent angiography and a saline infusion test were followed to confirm flow direction. RESULTS: Twenty-eight vessels were identified in 40 sides of the chest; of them, 45% had no valves. A mean 0.7 valves per chest side were identified; 23 (82.1%) of 28 valves were located above the second intercostal space (ICS). A mean 1.76 communicating veins were found between the IMV bifurcation. In all cadavers, a crossing vein connecting the left and right medial IMV was confirmed just below the xiphoid process. Fluorescent angiography and a saline infusion test proved that the retrograde flow was caudal through the bifurcated IMV to the communicating, intercostal, and crossing veins. CONCLUSION: The IMV valve was present in 55% of our subjects and located concentrically above the second ICS level. It is highly unlikely that the retrograde flow was disturbed because the retrograde anastomosis level was below the second ICS. Furthermore, the bifurcation, intercostal, and crossing veins across the xiphoid process enabled valve-less detour flow. Thus, retrograde IMV flow is considered safe.