BACKGROUND:Displacement of the distal fracture fragment is one of the most important facts that lead to cubitus varus fol owing pediatric supracondylar humeral fracture. Mainstream technique emphasized the restoration of posterior-ulnar deviation of the distal fragment. However, there is an absence of supportive evidences from biomechanical studies. OBJECTIVE:To establish models of extension-ulnar type of supracondylar humeral fracture and investigate the mechanical stability of reduced fracture with residual displacements within functional restoration standard, so as to provide mechanic evidences supporting the empirical rule of manipulative reduction-“better anterior than posterior, better radial than ulnar”. METHODS:The fresh cadaveric bone of right upper extremity from a 7-year-old child was scanned using CT. Models of supracondylar humeral fracture differing in contact area of the fracture site and displacement direction of the distal fragment were established and underwent loading tests. Stress in both anterior and posterior margin of the fracture site and Baumann angle were recorded, and data were analyzed and compared. RESULTS AND CONCLUSION:In comparison of stress in the posterior margin, the value was significantly greater in the posteromedial-displacement group than the others. Stress value in fracture with 75%contact area was significantly greater than the other three groups. In comparison of stress in the anterior margin, a significantly greater value was obtained in the posteromedial-displaced group. Stress value in fracture with 85%contact area was significantly greater. When comparing stress in posterior margin and anterior margin, the absolute increment of stress value was greater in posterior displacement group than in anterior displacement group. Baumann angle increased significantly when fragment displaced medial y. Above findings indicated that displacement direction altered the location of stress concentration. Stress augmentation was greater in posterior displacement group. Stress in related area significantly increased constantly when contact area of the fracture site reduced. Baumann changed obviously when fragment displaced medial y. The results preliminarily verify the hypothesis that displacement of the distal fragment was the main contributor to cubitus varus fol owing supracondylar humeral fracture. These findings provided certain evidences supporting the empirical rule“better anterior than posterior, better radial and ulnar”.

Objective:To analyze the applicability of Guo's massage system for tendon management in the treatment of chronic lateral ankle instability (CLAI).Methods:Randomized controlled trial design. A total of 82 CLAI patients in our hospital from January 2021 to January 2022 were selected as observation subjects and divided into two groups using a random number table method, with 41 patients in each group. The control group received ankle rehabilitation exercise (3 times for 1 course, 6 courses), while the research group received Guo's massage and tendon manipulation therapy (3 times for 1 course, 6 courses). Before and after treatment, ankle joint range of motion and Y-balance tests were performed. The American Association of Foot and Ankle Surgeons (AOFAS) ankle posterior foot function score was used to evaluate ankle joint function, the VAS scale was used to evaluate patient pain, and the Foot Ankle Energy Scale (FAAM) was used to evaluate the degree of ankle joint function damage and evaluate clinical efficacy.Results:The total effective rate was 95.12%(39/41) in the research group and that in the control group was 78.05%(32/41) ( χ2=5.15, P=0.023). The range of motion of plantar flexion, range of dorsiflexion, varus range of motion, valgus range of motion, anterior extension distance, posterior inward extension distance, and posterior outward extension distance increased in the research group after treatment were significantly higher than those in the control group ( t=11.32, 14.02, 8.70, 18.09, P<0.01). Forward, rear Inner, and rear outer extension distances of the ankle Y-balance test in the research group were significantly higher than those of the control group. The AOFAS score in the research group was significantly higher than that of the control group ( t=5.94, P<0.01), VAS score was significantly lower than that of the control group ( t=13.38, P<0.01). The daily activity score and exercise score in FAAM in the research group were significantly higher than those in the control group ( t=9.14, 14.99, P<0.01). Conclusion:The use of Guo's massage system for tendon management can improve the ankle function of CLAI patients, reduce their pain level, and promote the recovery of the patients.