Limb symmetry indexes can overestimate knee function after anterior cruciate ligament injury

Elizabeth A Wellsandt, Mathew J. Failla, Lynn Snyder-Mackler

Research output: Contribution to journalReview article

45 Citations (Scopus)

Abstract

STUDY DESIGN: Prospective cohort. BACKGROUND: The high risk of second anterior cruciate ligament (ACL) injuries after return to sport highlights the importance of return-to-sport decision making. Objective return-to-sport criteria frequently use limb symmetry indexes (LSIs) to quantify quadriceps strength and hop scores. Whether using the uninvolved limb in LSIs is optimal is unknown. OBJECTIVES: To evaluate the uninvolved limb as a reference standard for LSIs utilized in returnto- sport testing and its relationship with second ACL injury rates. METHODS: Seventy athletes completed quadriceps strength and 4 single-leg hop tests before anterior cruciate ligament reconstruction (ACLR) and 6 months after ACLR. Limb symmetry indexes for each test compared involved-limb measures at 6 months to uninvolved-limb measures at 6 months. Estimated preinjury capacity (EPIC) levels for each test compared involved-limb measures at 6 months to uninvolved-limb measures before ACLR. Second ACL injuries were tracked for a minimum follow-up of 2 years after ACLR. RESULTS: Forty (57.1%) patients achieved 90% LSIs for quadriceps strength and all hop tests. Only 20 (28.6%) patients met 90% EPIC levels (comparing the involved limb at 6 months after ACLR to the uninvolved limb before ACLR) for quadriceps strength and all hop tests. Twenty-four (34.3%) patients who achieved 90% LSIs for all measures 6 months after ACLR did not achieve 90% EPIC levels for all measures. Estimated preinjury capacity levels were more sensitive than LSIs in predicting second ACL injuries (LSIs, 0.273; 95% confidence interval [CI]: 0.010, 0.566 and EPIC, 0.818; 95% CI: 0.523, 0.949). CONCLUSION: Limb symmetry indexes frequently overestimate knee function after ACLR and may be related to second ACL injury risk. These findings raise concern about whether the variable ACL return-to-sport criteria utilized in current clinical practice are stringent enough to achieve safe and successful return to sport.

Original languageEnglish (US)
Pages (from-to)334-338
Number of pages5
JournalJournal of Orthopaedic and Sports Physical Therapy
Volume47
Issue number5
DOIs
StatePublished - May 2017

Fingerprint

Knee
Extremities
Anterior Cruciate Ligament Reconstruction
Humulus
Anterior Cruciate Ligament Injuries
Confidence Intervals
Anterior Cruciate Ligament
Athletes
Sports
Leg
Decision Making
Return to Sport

Keywords

  • ACL
  • Anterior cruciate ligament
  • Rehabilitation
  • Return to sport
  • Symmetry

ASJC Scopus subject areas

  • Physical Therapy, Sports Therapy and Rehabilitation
  • Medicine(all)

Cite this

Limb symmetry indexes can overestimate knee function after anterior cruciate ligament injury. / Wellsandt, Elizabeth A; Failla, Mathew J.; Snyder-Mackler, Lynn.

In: Journal of Orthopaedic and Sports Physical Therapy, Vol. 47, No. 5, 05.2017, p. 334-338.

Research output: Contribution to journalReview article

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title = "Limb symmetry indexes can overestimate knee function after anterior cruciate ligament injury",
abstract = "STUDY DESIGN: Prospective cohort. BACKGROUND: The high risk of second anterior cruciate ligament (ACL) injuries after return to sport highlights the importance of return-to-sport decision making. Objective return-to-sport criteria frequently use limb symmetry indexes (LSIs) to quantify quadriceps strength and hop scores. Whether using the uninvolved limb in LSIs is optimal is unknown. OBJECTIVES: To evaluate the uninvolved limb as a reference standard for LSIs utilized in returnto- sport testing and its relationship with second ACL injury rates. METHODS: Seventy athletes completed quadriceps strength and 4 single-leg hop tests before anterior cruciate ligament reconstruction (ACLR) and 6 months after ACLR. Limb symmetry indexes for each test compared involved-limb measures at 6 months to uninvolved-limb measures at 6 months. Estimated preinjury capacity (EPIC) levels for each test compared involved-limb measures at 6 months to uninvolved-limb measures before ACLR. Second ACL injuries were tracked for a minimum follow-up of 2 years after ACLR. RESULTS: Forty (57.1{\%}) patients achieved 90{\%} LSIs for quadriceps strength and all hop tests. Only 20 (28.6{\%}) patients met 90{\%} EPIC levels (comparing the involved limb at 6 months after ACLR to the uninvolved limb before ACLR) for quadriceps strength and all hop tests. Twenty-four (34.3{\%}) patients who achieved 90{\%} LSIs for all measures 6 months after ACLR did not achieve 90{\%} EPIC levels for all measures. Estimated preinjury capacity levels were more sensitive than LSIs in predicting second ACL injuries (LSIs, 0.273; 95{\%} confidence interval [CI]: 0.010, 0.566 and EPIC, 0.818; 95{\%} CI: 0.523, 0.949). CONCLUSION: Limb symmetry indexes frequently overestimate knee function after ACLR and may be related to second ACL injury risk. These findings raise concern about whether the variable ACL return-to-sport criteria utilized in current clinical practice are stringent enough to achieve safe and successful return to sport.",
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AU - Failla, Mathew J.

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N2 - STUDY DESIGN: Prospective cohort. BACKGROUND: The high risk of second anterior cruciate ligament (ACL) injuries after return to sport highlights the importance of return-to-sport decision making. Objective return-to-sport criteria frequently use limb symmetry indexes (LSIs) to quantify quadriceps strength and hop scores. Whether using the uninvolved limb in LSIs is optimal is unknown. OBJECTIVES: To evaluate the uninvolved limb as a reference standard for LSIs utilized in returnto- sport testing and its relationship with second ACL injury rates. METHODS: Seventy athletes completed quadriceps strength and 4 single-leg hop tests before anterior cruciate ligament reconstruction (ACLR) and 6 months after ACLR. Limb symmetry indexes for each test compared involved-limb measures at 6 months to uninvolved-limb measures at 6 months. Estimated preinjury capacity (EPIC) levels for each test compared involved-limb measures at 6 months to uninvolved-limb measures before ACLR. Second ACL injuries were tracked for a minimum follow-up of 2 years after ACLR. RESULTS: Forty (57.1%) patients achieved 90% LSIs for quadriceps strength and all hop tests. Only 20 (28.6%) patients met 90% EPIC levels (comparing the involved limb at 6 months after ACLR to the uninvolved limb before ACLR) for quadriceps strength and all hop tests. Twenty-four (34.3%) patients who achieved 90% LSIs for all measures 6 months after ACLR did not achieve 90% EPIC levels for all measures. Estimated preinjury capacity levels were more sensitive than LSIs in predicting second ACL injuries (LSIs, 0.273; 95% confidence interval [CI]: 0.010, 0.566 and EPIC, 0.818; 95% CI: 0.523, 0.949). CONCLUSION: Limb symmetry indexes frequently overestimate knee function after ACLR and may be related to second ACL injury risk. These findings raise concern about whether the variable ACL return-to-sport criteria utilized in current clinical practice are stringent enough to achieve safe and successful return to sport.

AB - STUDY DESIGN: Prospective cohort. BACKGROUND: The high risk of second anterior cruciate ligament (ACL) injuries after return to sport highlights the importance of return-to-sport decision making. Objective return-to-sport criteria frequently use limb symmetry indexes (LSIs) to quantify quadriceps strength and hop scores. Whether using the uninvolved limb in LSIs is optimal is unknown. OBJECTIVES: To evaluate the uninvolved limb as a reference standard for LSIs utilized in returnto- sport testing and its relationship with second ACL injury rates. METHODS: Seventy athletes completed quadriceps strength and 4 single-leg hop tests before anterior cruciate ligament reconstruction (ACLR) and 6 months after ACLR. Limb symmetry indexes for each test compared involved-limb measures at 6 months to uninvolved-limb measures at 6 months. Estimated preinjury capacity (EPIC) levels for each test compared involved-limb measures at 6 months to uninvolved-limb measures before ACLR. Second ACL injuries were tracked for a minimum follow-up of 2 years after ACLR. RESULTS: Forty (57.1%) patients achieved 90% LSIs for quadriceps strength and all hop tests. Only 20 (28.6%) patients met 90% EPIC levels (comparing the involved limb at 6 months after ACLR to the uninvolved limb before ACLR) for quadriceps strength and all hop tests. Twenty-four (34.3%) patients who achieved 90% LSIs for all measures 6 months after ACLR did not achieve 90% EPIC levels for all measures. Estimated preinjury capacity levels were more sensitive than LSIs in predicting second ACL injuries (LSIs, 0.273; 95% confidence interval [CI]: 0.010, 0.566 and EPIC, 0.818; 95% CI: 0.523, 0.949). CONCLUSION: Limb symmetry indexes frequently overestimate knee function after ACLR and may be related to second ACL injury risk. These findings raise concern about whether the variable ACL return-to-sport criteria utilized in current clinical practice are stringent enough to achieve safe and successful return to sport.

KW - ACL

KW - Anterior cruciate ligament

KW - Rehabilitation

KW - Return to sport

KW - Symmetry

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