BACKGROUND: Stress fractures of lower limbs are common for recruits and athletes, and affect their training to different extent. OBJECTIVE: To summarize the risk factors for the occurrence and development of stress fracture of lower extremity, then to raise the awareness of stress fracture of lower extremity and provide ideas for its prevention. METHODS: A computer-based search was conducted in PubMed, WanFang and CNKI databases from January 2009 to July 2019 with the keywords of “stress fracture, fatigue fracture, overuse injury, risk factors, recruits” in English and Chinese, respectively. A total of 786 relevant articles were retrieved, and 76 articles were eligible for the inclusion criteria. RESULTS AND CONCLUSION: (1) Sex and history of stress fracture have been identified as risk factors for stress fracture. Future studies should be inclined to identify the specific roles of other risk factors in the development of stress fracture. (2) In addition, biomechanical factors are likely to affect the occurrence of stress fracture of the lower limbs of recruits. (3) Therefore, improving the abnormal biomechanical parameters of the lower extremity during the training of recruits can develop a method to prevent the stress fracture of the lower limbs, and reduce the incidence of stress fracture through appropriate management.

Objective:To compare the clinical effects of external-internal four paper splints fixation at a fixed point with the routine paper splint fixation in the treatment of the unstable distal radius fracture.Methods:A total of 66 patients with type C1 or C2 distal radial fractures, from November 2016 to May 2019, were analyzed retrospectively. According to different external fixation methods, patients were divided into 2 groups with 33 patients in each group. Modified group treated with external-internal four paper splint fixation at a fixed point and normal group treated with routine paper splint fixation. The 4th and 6th weeks after the operation, the reduction of the distal radius fracture was evaluated based on anteroposterior and lateral wrist radiographs. After 3 months follow-up, the radial height, radial inclination and palm dip angle were measured and the healing time were recorded. The Gartland-Werley functional scale was used to evaluate the wrist function from four aspects of residual malformation, subjective evaluation, objective evaluation and complications, and to evaluate the clinical efficacy.Results:After 3 months follow-up, all patients got clinical healing. The loss of palm dip angle [(2.9 ± 2.4)° vs. (4.6 ± 3.2)°, t=-2.524], radial inclination [(3.4 ± 2.2)° vs. (5.0 ± 3.0)°, t=-2.506] and radial height [(2.4 ± 1.9) mm vs. (3.6 ± 2.1) mm, t=-2.302] in modified group were significantly less than those in normal group ( P<0.05). There was a lower Gartland-Werley score in modified group compared with normal group [(1.52 ± 2.75) vs. (5.76 ± 8.68); t=-2.677, P<0.05]. The excellent and good rate was 97.0% (32/33) in the modified group and 78.8% (26/33) in the nomal group. There was significant difference between two groups ( Z=-2.315, P=0.021). Conclusions:The external-internal four paper splint fixation at a fixed point can control the redisplacement of unstable distal radius fractures effectively, and maintain the reduction. The effect of modified paper splint fixation at a fixed point is better than routine paper splint fixation.

Objective:To analyze the relationship between arch index and foot kinematic parameters and their characteristics in stress fracture of lower extremity.Methods:A case-control study was performed for 108 recruits selected from a certain army unit in 2019. Before training, the recruits′ foot print images were collected by the capacitive plantar pressure measurement system to calculate their arch indices. The kinematic characteristics of the foot were analyzed by the dynamic gait posture analysis system. Spearman rank correlation analysis between arch index and foot kinematic parameters including landing elevation angle, toe-off angle, landing speed, landing varus angle, valgus amplitude and landing valgus speed were performed. Throughout the training, orthopedic physicians followed up the recruits, among whom 10 were excluded due to other types of lower extremity injuries. The arch index and foot kinematic characteristics were analyzed and compared between the remained recruits with stress fracture of lower extremity (fracture group, n=10) and those without lower extremity injury (control group, n=79). Results:(1) For the recruits, the arch index was 0.21(0.12,0.25), with landing elevation angle for (17.31±4.02)°, toe-off angle for (63.90±5.63)°, landing speed for (176.85±24.39)°/s, landing varus angle for (13.64±4.44)°, valgus amplitude for (12.16±3.42)°, and landing valgus speed for 382.50(311.05,474.80)°/s. (2) The landing varus angle ( r=0.25, P<0.01) and valgus amplitude ( r=0.14, P<0.05) were positively related to the arch index. (3) The arch index, toe-off angle and landing valgus speed were 0.20(0.07,0.24), (61.59±5.51)° and 336.00(251.02,428.67)°/s in fracture group, significantly lower than 0.23(0.17,0.26), (64.79±4.79)° and 381.20(313.63,470.92)°/s in control group ( P<0.05 or 0.01). There were no significant differences in the landing elevation angle, landing speed, landing varus angle and valgus amplitude between the two groups (all P>0.05). Conclusions:The change of the arch index can affect the landing varus angle and valgus amplitude of the foot. Recruits who suffer from stress fracture of lower extremity have the characteristics of higher arch, lower toe-off angle and lower landing valgus speed.