Quadriceps femoris strength deficits early in rehabilitation after ACL reconstruction identify risk of future contralateral ACL injury following return to sport in young athletes: A Preliminary analysis.
Mark V Paterno, Matthew P Ithurburn, Staci Thomas and 2 others
PMID 40638970WHAT IT FOUND
Young athletes who failed to reach 80% quadriceps strength symmetry about 14 weeks after ACL reconstruction had 4.4 times higher odds of injuring their opposite knee within 3 years of returning to sport.
However, they had 90% lower odds of re-injuring the operated knee.
Key findings
01Failure to achieve >80% quadriceps strength limb symmetry index at the early testing session was associated with approximately 4 times higher odds of sustaining a contralateral second ACL injury.
02Failure to achieve >80% quadriceps strength limb symmetry index at the early testing session was associated with approximately 90% lower odds of sustaining an ipsilateral second ACL injury.
03Early quadriceps strength limb symmetry index was strongly and positively associated with patient-reported outcomes, functional hop testing, and quadriceps strength at the time of medical clearance to return to sport.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
Read the rest of this summary
You get three full summaries a month, free, and we do not ask for a card. Search, the TL;DRs and your library stay unlimited either way.
What it does not show
The sample size was small (51 participants), and the authors describe this as preliminary pilot work. Rehabilitation protocols and surgical graft types were not standardized or controlled across participants. The study population was highly specific: young athletes intending to return to Level I/II pivoting and cutting sports, so results may not generalize to older adults or those returning to lower-level activities. The finding that low early strength reduced the risk of ipsilateral re-injury is counter-intuitive and may reflect compensatory loading of the opposite limb rather than a protective effect. Confounding variables such as age, sex, and graft type were not significantly associated with injury risk in the logistic regression, but the small sample limits the ability to fully adjust for these factors.
Declared interests
No specific conflicts of interest or funding sources are disclosed in the provided text.
The easy way to misread this
Do not interpret the 90% lower odds of ipsilateral re-injury in the low-strength group as evidence that weak quadriceps protect the operated knee. This finding likely reflects a compensatory shift of load to the opposite limb, which explains the simultaneous increase in contralateral injury risk.
Summarised by AI from the full paper, without a clinician reviewing it. Check it against the source before it changes what you do. Read it on PubMed →