{"id":11112,"date":"2024-05-20T06:00:48","date_gmt":"2024-05-20T05:00:48","guid":{"rendered":"https:\/\/blogs.bmj.com\/bjsm\/?p=11112"},"modified":"2024-05-13T14:36:04","modified_gmt":"2024-05-13T13:36:04","slug":"hip-and-calf-muscle-strength-after-acl-injury","status":"publish","type":"post","link":"https:\/\/blogs.bmj.com\/bjsm\/2024\/05\/20\/hip-and-calf-muscle-strength-after-acl-injury\/","title":{"rendered":"Hip and calf muscle strength after ACL injury"},"content":{"rendered":"

Key words<\/em>:\u00a0<\/em><\/b>ACL, muscle strength, rehabilitation, hip<\/span><\/em><\/p>\n

This blog summarises the<\/span> findings from a recent <\/span>systematic review<\/span><\/a> on hip and lower leg strength after anterior cruciate ligament (ACL) injury) (1).<\/span><\/p>\n

Why is this study important?<\/b><\/p>\n

Muscle weakness is a key target of ACL injury rehabilitation, and strength deficits of the knee muscles (quadriceps and hamstrings) are often as high as 10-20% compared to uninjured controls, even several years after injury. However, less is known about muscle strength of the hip and lower leg (calf). Hip and lower leg muscles are crucial to many functional tasks and sporting activities (e.g., hopping, jumping). All\u00a0<\/span>existing evidence was reviewed to provide a single go-to summary of hip and lower leg strength for clinicians and researchers.<\/span><\/p>\n

How did we go about this?<\/b><\/p>\n

We conducted a systematic review and meta-analysis of all studies that measured hip and\/or lower leg strength after primary (first time) ACL injury. Participants were aged 18-40 years at the time of injury, but no other restrictions were placed on the people included.\u00a0<\/span>Muscle strength had to be measured with a hand-held or computerised (isokinetic) dynamometer. Studies had to report muscle strength for the ACL limb compared to either the: (i) contralateral limb (within-person comparison); or (ii) uninjured control limb (between-person comparison). We investigated both comparisons, as, while within-person comparisons are more common, the contralateral limb can also be affected by weakness after ACL injury, and comparison to an uninjured control might be more appropriate.<\/span><\/p>\n

We grouped data by the strength outcome (e.g. hip abduction) and type of comparison (between-person or within-person), and conducted meta-analyses where two or more studies were available.\u00a0<\/span><\/p>\n

What did the study find?<\/b><\/p>\n

We included 28 studies of 1103 ACL injured people (38% women) and 1145 uninjured controls (81% women). All except one study followed people after ACL reconstruction (ACLR), and most studies looked at strength in the first year post-surgery.<\/span><\/p>\n

16 studies used a hand-held dynamometer (similar to common methods in clinical practice);12 studies measured strength with an isokinetic dynamometer.<\/span><\/p>\n

Overall, there was no consistent evidence for major or widespread hip or lower leg muscle weakness:<\/span><\/p>\n