title: Return to sport: Does excellent 6-month strength and function following ACL reconstruction predict midterm outcomes?
abstract: OBJECTIVE
  The purpose of this study was to determine whether patients with excellent 6-month functional testing after ACL reconstruction had (1) higher risk of subsequent ACL tears, (2) superior knee function, and (3) increased activity levels compared to those with delayed clearance for return to sports at midterm follow-up.
  
  
  METHODS
  A total of 223 patients underwent primary ACL reconstruction by a single surgeon and had functional and isokinetic testing performed 6 months post-operatively between 1998 and 2005. Of the 223 patients, 52 (23 %) made the excellent group and were allowed return to sport at 6 months, and the remaining 171 (77 %) constituted the delayed group. Rate of ACL graft tear and native contralateral ACL tear was compared between groups. In addition, IKDC and Tegner scores were compared at a mean 4-year follow-up.
  
  
  RESULTS
  The graft rupture rate was similar in the excellent group (3.8 %, n = 2) compared to the delayed group (4.7 %, n = 8; p = 0.30). However, there was a higher rate of contralateral ACL tear in the excellent group (15.4 %, n = 8 vs. 5.3 %, n = 9; p = 0.003). The excellent 6-month group had superior IKDC scores (94.3 ± 6.4 vs. 90.9 ± 9.7; p = 0.04) and Tegner scores (6.6 ± 1.8 vs. 5.7 ± 1.6; p = 0.01).
  
  
  CONCLUSIONS
  Patients with an excellent performance on their isokinetic strength and functional testing at 6 months after ACL reconstruction have superior knee function and higher activity levels at midterm follow-up. However, these patients appear to be at greater risk of contralateral ACL injury, which may be related to their increased activity level. When isokinetic and functional testing is used for return-to-sport decisions, physicians should caution patients about the risk of contralateral ACL injury for high performing patients.
  
  
  METHODS
  Retrospective Review with Control, Level III.
authors.affiliation: Department of Orthopedic Surgery and The Sports Medicine Center, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
authors.forename: Paul L
authors.initials: PL
authors.lastname: Sousa
authors.affiliation: Department of Orthopedic Surgery and The Sports Medicine Center, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Krych
authors.affiliation: Department of Orthopedic Surgery and The Sports Medicine Center, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Cates
authors.affiliation: Department of Orthopedic Surgery and The Sports Medicine Center, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Levy
authors.affiliation: Department of Orthopedic Surgery and The Sports Medicine Center, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Stuart
authors.affiliation: Department of Orthopedic Surgery and The Sports Medicine Center, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA. Dahm.Diane@Mayo.edu.
authors.forename: Diane L
authors.initials: DL
authors.lastname: Dahm
mesh_terms: D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000503:physiopathology / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries / Q000503:physiopathology / Q000534:rehabilitation / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods / Q000534:rehabilitation*; D001182:Arthroscopy; D016022:Case-Control Studies; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D020127:Recovery of Function; D012189:Retrospective Studies; D000068958:Return to Sport; D016896:Treatment Outcome; D055815:Young Adult
keywords: ACL reconstruction; Functional testing; Isokinetic strength; Outcomes; Return to sport