title: Neuromuscular Evaluation With Single-Leg Squat Test at 6 Months After Anterior Cruciate Ligament Reconstruction.
abstract: BACKGROUND
  Criteria for return to unrestricted activity after anterior cruciate ligament (ACL) reconstruction varies, with some using time after surgery as the sole criterion-most often at 6 months. Patients may have residual neuromuscular deficits, which may increase the risk of ACL injury. A single-leg squat test (SLST) can dynamically assess for many of these deficits prior to return to unrestricted activity.
  
  
  OBJECTIVE
  A significant number of patients will continue to exhibit neuromuscular deficits with SLST at 6 months after ACL reconstruction.
  
  
  METHODS
  Cross-sectional study; Level of evidence, 3.
  
  
  METHODS
  Patients using a standardized accelerated rehabilitation protocol at their 6-month follow-up after primary ACL reconstruction were enrolled. Evaluation included bilateral SLST, single-leg hop distance, hip abduction strength, and the subjective International Knee Documentation Committee (IKDC) score.
  
  
  RESULTS
  Thirty-three patients were enrolled. Poor performance of the operative leg SLST was found in 15 of 33 patients (45%). Of those 15 patients, 7 (45%) had concomitant poor performance of the nonoperative leg compared with 2 of 18 patients (11%) in those who demonstrated good performance in the operative leg. The poor performers were significantly older (33.6 years) than the good performers (24.2 years) (P = .007). Those with poor performance demonstrated decreased hip abduction strength (17.6 kg operative leg vs 20.5 kg nonoperative leg) (P = .024), decreased single-leg hop distance (83.3 cm operative leg vs 112.3 cm nonoperative leg) (P = .036), and lower IKDC scores (67.9 vs 82.3) (P = .001).
  
  
  CONCLUSIONS
  Nearly half of patients demonstrated persistent neuromuscular deficits on SLST at 6 months, which is when many patients return to unrestricted activity. Those with poor performance were of a significantly older age, decreased hip abduction strength, decreased single-leg hop distance, and lower IKDC subjective scores.
  
  
  CONCLUSIONS
  The SLST can be used to identify neuromuscular risk factors for ACL rupture. Many patients at 6 months have persistent neuromuscular deficits on SLST. Caution should be used when using time alone to determine when patients can return to unrestricted activity.
authors.affiliation: Kaiser Permanente Los Angeles Medical Center, Los Angeles, California, USA.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Hall
authors.affiliation: Nirschl Orthopaedic Center, Arlington, Virginia, USA.
authors.forename: Ronald S
authors.initials: RS
authors.lastname: Paik
authors.affiliation: Select Physical Therapy, Los Angeles, California, USA.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Ware
authors.affiliation: Kerlan-Jobe Orthopaedic Clinic, Los Angeles, California, USA.
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Mohr
authors.affiliation: Kerlan-Jobe Orthopaedic Clinic, Los Angeles, California, USA.
authors.forename: Orr
authors.initials: O
authors.lastname: Limpisvasti
keywords: anterior cruciate ligament; neuromuscular evaluation; return to unrestricted activity; single-leg squat test