No Association Between Hamstrings-to-Quadriceps Strength Ratio and Second ACL Injuries After Accounting for Prognostic Factors: A Cohort Study of 574 Patients After ACL-Reconstruction

Sports Medicine - Open

Table 2 Hamstrings-to-quadriceps strength ratio for the odds of sustaining a second ACL injury

	Value	n (%) of event	Univariable*		Area under ROC curve (95%CI)	Multivariable**
	Value	n (%) of event	OR (95%CI)	p value	Area under ROC curve (95%CI)	OR (95%CI)	p value
HQ-ratio (ACL reconstructed side) (%)	30.9–< 52.8	33 (17.2%)
	52.8–< 61.0	14 (7.3%)
	61.0–139.0	17 (8.9%)	0.97 (0.95–1.00)	0.025	0.60 (0.52–0.67)	0.98 (0.95–1.01)	0.16
Time to RT preinjury sport level (months)	3.5–< 11.4	25 (13.1%)
	11.4–< 12.8	23 (12.0%)
	12.8–24.7	16 (8.4%)	0.96 (0.92–1.01)	0.13	0.54 (0.47–0.61)	0.96 (0.91–1.01)	0.12
Sex, n (%)	Male	38 (13.2%)
	Female	26 (9.1%)	0.65 (0.38–1.11)	0.11	0.55 (0.49–0.62)	0.73 (0.41–1.30)	0.28
Graft choice, n (%)	Hamstring tendon autograft	56 (12.1%)
	Patellar tendon autograft	6 (6.2%)	0.48 (0.20–1.15)	0.098	0.54 (0.50–0.58)	0.52 (0.20–1.34)	0.18
Age at primary reconstruction, n (%)	12.9–< 18.3	31 (16.2%)
	18.3–< 24.9	23 (12.0%)
	24.9–68.0	10 (5.2%)	0.92 (0.87–0.96)	0.0002	0.64 (0.58–0.71)	0.94 (0.89–0.98)	0.008
Tegner preinjury, n (%)	6–< 8	9 (5.1%)
	8–< 9	23 (14.8%)
	9–10	32 (13.1%)	1.32 (1.06–1.66)	0.015	0.59 (0.52–0.65)	1.17 (0.89–1.52)	0.26
Body mass index, n (%)	15.8–< 22.5	25 (13.1%)
	22.5–< 24.5	18 (9.3%)
	24.5–59.2	21 (11.1%)	1.02 (0.94–1.10)	0.60	0.48 (0.40–0.55)

A bold p-value indicates a significance (p < 0.05). ACL anterior cruciate ligament, CI confidence intervals, HQ hamstrings-to-quadriceps, n numbers, OR odds ratio, ROC receiver operating curve, RT return to, Tegner tegner activity scale
*All analyses were performed with univariable logistic regression
**Multivariable logistic regression model including the hamstrings-to-quadriceps strength ratio (ACL reconstructed side), time to return to preinjury sport level (months), sex, graft choice, age at index operation and Tegner preinjury. Area under ROC curve with 95% CI for multivariable model = 0.69 (0.62–0.76)