Female athletes with ligament dominance exhibiting altered hip and ankle muscle co-contraction patterns compared to healthy individuals during single-leg landing

BackgroundAnterior cruciate ligament (ACL) injury is one of the most serious knee injuries and occurs frequently during exercise. Altered hip and ankle muscle co-contraction patterns may contribute to dynamic knee valgus and ACL injury mechanisms. Lack of dynamic control of ground reaction force (GRF) is known to be contributing factor for ACL injury by placing excessive force on passive structures. Muscle co-contraction is a dynamic mechanism for GRF absorption. Therefore, any alterations in co-contraction might be a risk factor for ACL injury. Ligament dominance is a term to define individuals who rely more on ACL ligament for GRF control.Research questionThis study aimed to compare the muscle co-contraction patterns of distal and proximal knee muscles during single leg landing in female athletes with and without ligament dominance.MethodsThis is a cross-sectional study. A total of 54 female athletes were assigned to the healthy (n = 27) and ligament dominance (n = 27) group based on their Tuck Jump test scores. The electromyography activity of the gluteus medius, adductor longus, tibialis anterior, peroneus longus, medial and lateral gastrocnemius was measured by an electromyography in drop down a 30-cm-high stair. A Multivariate Analysis of Variance (MANOVA) was used for statistical analysis (p ≤ 0.05).ResultsThe two groups demonstrated an overall significantly different muscle co-contraction patterns (P < 0.05). There was a decreased in co-contraction of proximal group and an increased co-contraction in the distal muscles in ligament dominant group.SignificanceThe findings have provided evidence to support the notion of neuromuscular imbalances in ligament dominance deficit. These findings can be useful for the coaches and experts to design preventive exercises and modify the current programs for the people affected by ligament dominance.     

后路全椎板切除减压并椎弓根内固定治疗胸椎后纵韧带骨化合并黄韧带骨化

目的探讨对胸椎后纵韧带骨化(ossification of posterior longitudinal ligament,OPLL)合并黄韧带骨化(ossification of ligamentum flavum,OLF)患者行后路全椎板切除减压并椎弓根内固定治疗的临床疗效。方法回顾性研究2008年7月~2013年4月,15例胸椎OPLL并OLF患者行后路全椎板切除减压并椎弓根内固定术治疗。分别统计患者一般情况、手术时间、出血量、卧床时间、术后并发症发生率、术前术后日本骨科学会(Japanese Orthopaedic Association,JOA)评分,并进行比较。结果平均随访38.7个月,患者术前、术后3个月及末次随访时JOA评分分别为3.9±1.2、8.1±2.2及10.3±2.5,差异具有统计学意义(P<0.05)。术中1例患者出现脑脊液漏,术后1例患者出现浅表伤口感染,1例患者出现血肿。结论胸椎OPLL并OLF患者行全椎板切除减压并椎弓根内固定术治疗,可获得满意的临床疗效。但该术式容易造成严重脊髓损伤,对术者技巧要求较高。     

Unstable Simple Elbow Dislocation Treated with the Repair of Lateral Collateral Ligament Complex

Background

Unstable simple elbow dislocation (USED) repair is challenged by the maintenance of joint reduction; hence, primary repair or reconstruction of disrupted ligaments is required to maintain the congruency and allow early motion of the elbow. We evaluated the effectiveness and the outcome of lateral collateral ligament (LCL) complex repair with additional medial collateral ligament (MCL) repair in cases of USED.

Methods

We retrospectively reviewed 21 cases of diagnosed USED without fractures around the elbow that were treated with primary ligament repair. In all cases, anatomical repair of LCL complex with or without common extensor origin was performed using suture anchor and the bone tunnel method. Next, the instability and congruency of elbow for a full range of motion were evaluated under the image intensifier. MCL was repaired only if unstable or incongruent elbow was observed. Clinical outcomes were evaluated using the Mayo elbow performance score (MEPS) and radiographic outcomes on last follow-up images.

Results

All cases achieved a stable elbow on radiographic and clinical results. LCL complex repair alone was sufficient to obtain the stable elbow in 17 of 21 cases. Four cases required additional MCL repair after restoration of the LCL complex. The overall mean MEPS was 91 (range, 70 to 100): excellent in 12 cases, good in 7 cases, and fair in 2 cases. All 17 cases with LCL complex repair only and 2 of 4 cases with additional MCL repair had excellent or good results by MEPS.

Conclusions

USED requires surgical treatment to achieve a congruent and stable joint. If the repair of lateral stabilizer such as LCL complex acquires enough joint stability to maintain a full range of motion, it may not be necessary to repair the medial stabilizer in all cases of USED.