| Summary: | 碩士 === 國立成功大學 === 物理治療研究所 === 99 === Background: Anterior cruciate ligament (ACL) rupture is common injury among young athletes. The patients might suffer functional impairment and instability, and ACL reconstruction (ACLR) surgeries were generally recommended to restore knee function and stability. Besides, numerous studies endeavored to develop an optimal rehabilitation program to restore knee function or to design injury prevention programs. However, these studies mainly focused on sagittal plane analysis in landing phase. On the other hand, recent studies have shown that single-bundle ACL reconstruction may not restore tibial rotation even though anterior tibial translation has been reestablished. Although current literature demonstrates that small knee flexion angle during landing was the major ACL loading mechanisms, several biomechanical studies have shown that tibial internal rotation was also the risk factor forACL injury. However, little has been done to investigate the control strategy on transverse plane in one-leg hopping test or to investigate the effects of exercise training focusing on tibial rotatory control. Purpose: To investigate the landing strategies for the patients with ACLR 2 years post surgery and the effects of neuromuscular training focusing on the control of tibial rotation. Methods: 10 ACLR subjects (9 subjects with BPTB and 1 subject with ST/G) were recruited to execute the neuromuscular training for at least three months. The assessments for knee function, ACL laxity, knee strength, the circumference of thigh, and one leg hopping test were conducted before and after training. Kinematic and electromyography data were collected simultaneously during one leg hopping test. Landing strategies were especially analyzed focusing on the control of tibial rotation immediately after landing. Several Wilcoxon signed ranked tests were conducted to examine the differences in the related measurements between the reconstructed legs and the uninvolved legs for the base-line assessment and the assessment after training. The training effects for the reconstructed legs were also examined by the Wilcoxon signed ranked tests. Results: Significantly improved knee function, stronger knee flexors and extensors, and significantly larger hopping distance were found in the reconstructed legs after completing the training protocol. After neuromuscular training, symmetry index of hopping distance was decreased from 13.1％ to 4.9％. Moreover, significant alternations in landing strategies were observed in all subjects who had hopped with more dangerous landing strategy (TIR). After training, all the subjects adopted TER landing strategies with significantly improved neuromuscular efficiency of hamstrings and a trend of more knee flexion angle and less internal rotation angle at landing. Conclusion: This study was the first research to identify the landing strategies focusing on tibial rotation control immediately after landing for patients with single-bundle ACLR. Nearly one third of patients were found to adopt TIR landing strategies which might render ACL into higher re-injury rate. However, after undertaking more than 3 months of neuromuscular training, alternations of tibial rotation control were found in subjects with TIR strategies and significantly improved hopping distance were found in all ACLR subjects. In this study, abnormal landing strategies have been proved to be a modifiable factor. With properly designed neuromuscular training program, significantly improvement in knee function, knee strength and hopping performance were reported and the reduction of ACL re-injury rate could be expected.
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