Bates, Nathaniel

AbstractIntroduction Second anterior cruciate ligament (SACL) injuries are a devastating complication following return to sport (RTS). Appropriate and safe RTS criteria that reduce the risk of SACL injuries are needed. The goal of this study was to investigate the relationship between functional and isokinetic testing at 6 months following primary ACL reconstruction (ACLR) as risk factors for SACL injuries.Methods Patients with primary ACLR from 1990 to 2010 were identified. Those with 6-month postoperative functional and isokinetic testing and a minimum of 2-year follow-up were included. Functional testing included vertical jump, single-leg hop, and single-leg triple hop. Isokinetic testing included concentric quadriceps and hamstrings (HSs) strength at 60 and 180 degree/s speeds. Statistical analysis evaluated the significance of the various tests between those with and without a secondary tear.Results In total, 344 patients with a mean age of 26.0 ± 9.8 years at an average time of 9.1 ± 3.5 years of follow-up were analyzed. Fifty-nine patients (17%) experienced SACL injuries at an average time of 4.8 years following ACLR with 34 (58%) ipsilateral graft ruptures and 25 (43%) contralateral tears. Several isokinetic measures were significantly different between the NO SACL and the SACL groups: quadriceps 60 degree/s limb symmetry index (LSI) (75 vs. 82% p = 0.01), HS 60 degree/s LSI (92 vs. 97%, p = 0.04), quadriceps 180 degree/s involved/body weight (BW) (41 vs. 47%, p = 0.04), and HS 180 degree/s involved/BW (30 vs. 34%, p = 0.04). Patients with involved limb peak quadriceps torque value greater than 65 or 50% of BW (60 and 180 degree/s) had a 2.2 and 3.1 times higher risk of an SACL injury.Conclusions Patients with certain elevated isokinetic scores in the injured limb at 6 months after ACLR experienced a higher rate of subsequent ACL injuries than those who had lower peak torque. Although a quantitative only analysis may not be sufficient to determine RTS criteria, clinicians should caution high-performing patients about the risk of subsequent ACL injury.Level of Evidence Cohort study; 3.

Background Eccentric hamstring strength and hamstring/quadriceps strength ratios have been identified as modifiable risk factors of hamstring strains. Additionally, those strength and flexibility characteristics are commonly used as clinical tests to monitor progress of athletes with acute or chronic hamstring strains. Although hamstring strains are common among basketball athletes, normative values of knee strength and flexibility characteristics are scarce. Normative values for these athletes would be important in prevention and management of hamstring strains. Purpose To establish quadriceps and hamstring isokinetic strength and flexibility values among high school basketball athletes and examine the effects of sex and age. Study Design Cross-sectional research Methods Isokinetic knee muscular strength (concentric quadriceps [QuadC], concentric hamstring [HamC], eccentric hamstring [HamE], and strength ratios ([HamC/QuadC and HamE/Quad]), flexibility of hip flexors and quadriceps during a Modified Thomas test, and flexibility of hip extensors and hamstring during passive straight leg raise (SLR) and passive knee extension (PKE) tests were measured. Effects of sex and age were analyzed using t-tests and analysis of variance, respectively with Bonferroni corrected post hoc tests ( p ≤0.01). Results A total of 172 high school basketball athletes (64 males/108 females; mean age (range): 15.7 (14-18) years old) participated in the study. Male athletes were significantly stronger than female athletes (QuadC: p <0.001; HamC: p <0.001) while no differences were observed in strength ratio (HamC/QuadC: p =0.759-0.816; HamE/QuadC: p =0.022-0.061). Among male athletes, a significant effect of age on quadriceps and hamstring strength was observed: older male athletes were stronger than younger male athletes. Contrarily, there were no effects of age on strength among female athletes. There were significant sex differences in quadriceps flexibility, SLR, and PKE (female athletes were more flexible; p =0.001-0.005) while no sex differences were found in hip flexor flexibility ( p =0.105-0.164). There were no effects of age for any flexibility variables within male and female athletes ( p =0.151-0.984). Conclusion The current results provide normative values for hamstring strength and flexibility in high school basketball athletes. These normative values may further assist sports medicine specialists to develop screening tests, interventions, and return-to-sport criteria in this population. Level of Evidence 3B