Variables Associated With Return to Sport After ACL Surgery
Variables Associated With Return to Sport After ACL Surgery
Anterior cruciate ligament (ACL) tears are the most commonly reported knee injury in athletes, with nearly 300,000 ACL reconstructions (ACLRs) performed yearly in the USA. Previous reports indicate that 98% of orthopaedic surgeons recommend surgery if patients wish to return to sport, but not all patients return to sport following ACLR. Clinical guidelines suggest that patients should be expected to return to sport by 9 months postsurgery, but many patients have not achieved this activity level up to 18 months after receiving clearance to return to sport. Declines in sports participation compared with preinjury levels are noted as far as 5 and 7 years postsurgery, though reasons for activity level changes may be unrelated to knee function.
Improved understanding of variables influencing patients' ability to return to sports is needed. Return to sport recommendations following ACLR are varied and often based on clinical experience or reviews reporting the criteria utilised in randomised controlled trials (RCTs). Most return to sport criteria following ACLR includes assessments of knee impairment and function, such as knee range of motion (ROM), quadriceps strength and functional test performance. Achieving knee ROM equivalent to the uninvolved limb is frequently emphasised as ROM asymmetry between limbs has been linked to worse subjective outcomes 10 years postsurgery, though the ability of these patients to return to sport is unknown. Quadriceps and hamstring strength are the most commonly utilised objective criteria when determining patient readiness to return to sport, and published reports note persistent quadriceps weakness years after surgery. Typical criteria include a quadriceps limb symmetry index (LSI) equivalent to >80–90% of the opposite side. Although quadriceps weakness may alter knee kinematics during running and cutting, the actual relationship between quadriceps strength and functional test performance such as hop testing is unclear. Single-leg hop LSI ≥90% is also often cited, but the relationship between functional test performance and athletic performance is not well established. Despite postsurgical emphasis on strengthening and functional performance, abnormal lower limb kinematics are evident during hopping and jumping 2–4 years following ACLR. The ability of these frequently utilised clinical criteria to predict athletes' ability to return to sport is unknown.
Some patients without impairments in ROM or strength may choose not to return to their preinjury level of sports participation for reasons unrelated to knee function, such as lifestyle changes. Conversely, some patients reporting substantial knee impairments after ACLR return to competitive sport. Psychological variables may partially explain the lack of association between physical function and return to sport. Fear of movement and reinjury, or kinesiophobia, is one of the most commonly cited reasons for patients not returning to sport following ACLR. Although kinesiophobia declines during rehabilitation, it is still reported in as high as 20–24% of patients. Higher perceived self-efficacy (one's judgement about whether one can perform a task) and an internal health locus of control have been linked to better quality of life scores, knee function and subjective outcomes post-ACLR. Despite these reports, psychological measures are not typically used in current return to sport criteria following ACLR.
The evidence supporting current clinical criteria used to allow patients to return to sport following ACLR has not been thoroughly examined. The primary purpose of this systematic review was to summarise the published literature reporting on knee impairment, functional and psychological variables proposed to be associated with return to sport following ACLR. Knowledge of variables associated with athletes' return to play following surgery may aid clinicians in counselling patients and focusing rehabilitation programmes. The secondary purpose of this review was to provide recommendations for future research to develop evidence-based return to sport criteria.
Background
Anterior cruciate ligament (ACL) tears are the most commonly reported knee injury in athletes, with nearly 300,000 ACL reconstructions (ACLRs) performed yearly in the USA. Previous reports indicate that 98% of orthopaedic surgeons recommend surgery if patients wish to return to sport, but not all patients return to sport following ACLR. Clinical guidelines suggest that patients should be expected to return to sport by 9 months postsurgery, but many patients have not achieved this activity level up to 18 months after receiving clearance to return to sport. Declines in sports participation compared with preinjury levels are noted as far as 5 and 7 years postsurgery, though reasons for activity level changes may be unrelated to knee function.
Improved understanding of variables influencing patients' ability to return to sports is needed. Return to sport recommendations following ACLR are varied and often based on clinical experience or reviews reporting the criteria utilised in randomised controlled trials (RCTs). Most return to sport criteria following ACLR includes assessments of knee impairment and function, such as knee range of motion (ROM), quadriceps strength and functional test performance. Achieving knee ROM equivalent to the uninvolved limb is frequently emphasised as ROM asymmetry between limbs has been linked to worse subjective outcomes 10 years postsurgery, though the ability of these patients to return to sport is unknown. Quadriceps and hamstring strength are the most commonly utilised objective criteria when determining patient readiness to return to sport, and published reports note persistent quadriceps weakness years after surgery. Typical criteria include a quadriceps limb symmetry index (LSI) equivalent to >80–90% of the opposite side. Although quadriceps weakness may alter knee kinematics during running and cutting, the actual relationship between quadriceps strength and functional test performance such as hop testing is unclear. Single-leg hop LSI ≥90% is also often cited, but the relationship between functional test performance and athletic performance is not well established. Despite postsurgical emphasis on strengthening and functional performance, abnormal lower limb kinematics are evident during hopping and jumping 2–4 years following ACLR. The ability of these frequently utilised clinical criteria to predict athletes' ability to return to sport is unknown.
Some patients without impairments in ROM or strength may choose not to return to their preinjury level of sports participation for reasons unrelated to knee function, such as lifestyle changes. Conversely, some patients reporting substantial knee impairments after ACLR return to competitive sport. Psychological variables may partially explain the lack of association between physical function and return to sport. Fear of movement and reinjury, or kinesiophobia, is one of the most commonly cited reasons for patients not returning to sport following ACLR. Although kinesiophobia declines during rehabilitation, it is still reported in as high as 20–24% of patients. Higher perceived self-efficacy (one's judgement about whether one can perform a task) and an internal health locus of control have been linked to better quality of life scores, knee function and subjective outcomes post-ACLR. Despite these reports, psychological measures are not typically used in current return to sport criteria following ACLR.
The evidence supporting current clinical criteria used to allow patients to return to sport following ACLR has not been thoroughly examined. The primary purpose of this systematic review was to summarise the published literature reporting on knee impairment, functional and psychological variables proposed to be associated with return to sport following ACLR. Knowledge of variables associated with athletes' return to play following surgery may aid clinicians in counselling patients and focusing rehabilitation programmes. The secondary purpose of this review was to provide recommendations for future research to develop evidence-based return to sport criteria.