A critical analysis of limb symmetry indices of hop tests in athletes after anterior cruciate ligament reconstruction: A case control study.

BACKGROUND: Hop tests are frequently used to determine return to sports (RTS) after anterior cruciate ligament reconstruction (ACLR). Given that bilateral deficits are present after ACLR, this may result in a falsely high limb symmetry index (LSI), since LSI is calculated as a ratio between the values of the limbs. HYPOTHESIS: Athletes after ACLR would achieve LSI>90% for the hop test. Secondly, athletes after ACLR demonstrate decreased jump distance on the single hop for distance (SLH) and triple leg hop for distance (TLH) and decreased number of hops for the side hop (SH) for both involved and uninvolved limbs compared to normative data of sex, age and type of sports matched healthy athletes. MATERIALS AND METHODS: Fifty-two patients (38 males mean age 23.9±3.5years; 14 females mean age 21.7±3.5 years) who had undergone an ACLR participated in this study. Patients performed the 3 hop tests at a mean time of 7 months after ACLR. Hop distance, number of side hops and LSI were compared with normative data of 188 healthy athletes. RESULTS: The differences between the involved limb and the uninvolved limb were significant in all hop tests (SLH P=0.003, TLH P=0.003, SH P=0.018). For females, only significant between limb differences were found in the SLH (P=0.049). For both the SLH and the TLH, significant differences were found between the involved limb and the normative data (males; SLH P<0.001, TLH P<0.001; females; SLH P<0.001, TLH P=0.006) and between the uninvolved limb and the normative data for both males and females (males; SLH P<0.001, TLH P<0.001; females; SLH P=0.003, TLH P=0.038). For the SH, only significant differences were found between the involved limb and the normative values in males (P=0.033). CONCLUSION: Athletes who have undergone an ACLR demonstrate bilateral deficits on hop tests in comparison to age and sex matched normative data of healthy controls. Using the LSI may underestimate performance deficits and should therefore be analyzed with caution when used as a criterion for RTS after ACLR. LEVEL OF EVIDENCE: III, case control study.

Jump Landing Characteristics Predict Lower Extremity Injuries in Indoor Team Sports.

The aim of this study is to investigate the predictive value of landing stability and technique to gain insight into risk factors for ankle and knee injuries in indoor team sport players. Seventy-five male and female basketball, volleyball or korfball players were screened by measuring landing stability after a single-leg jump landing and landing technique during a repeated counter movement jump by detailed 3-dimensional kinematics and kinetics. During the season 11 acute ankle injuries were reported along with 6 acute and 7 overuse knee injuries by the teams' physical therapist. Logistic regression analysis showed less landing stability in the forward and diagonal jump direction (OR 1.01-1.10, p≤0.05) in players who sustained an acute ankle injury. Furthermore landing technique with a greater ankle dorsiflexion moment increased the risk for acute ankle injury (OR 2.16, p≤0.05). A smaller knee flexion moment and greater vertical ground reaction force increased the risk of an overuse knee injury (OR 0.29 and 1.13 respectively, p≤0.05). Less one-legged landing stability and suboptimal landing technique were shown in players sustaining an acute ankle and overuse knee injury compared to healthy players. Determining both landing stability and technique may further guide injury prevention programs.

Effect of fatigue on landing performance assessed with the landing error scoring system (less) in patients after ACL reconstruction. A pilot study.

BACKGROUND: Fatigue has been shown to affect performance of hop tests in patients after anterior cruciate ligament reconstruction (ACLR) compared to uninjured controls (CTRL). This may render the hop test less sensitive in detecting landing errors. The primary purpose of this study was to investigate the effect of lower extremity fatigue on landing performance assessed with the Landing Error Scoring System (LESS) in patients after ACLR compared to a CTRL group. It is plausible that fatigue would have an effect on confidence and risk appraisal in the ACLR group. The secondary purpose was to determine the relationship between psychological responses and LESS scores after fatigue. METHODS: Twelve patients following ACLR (6 males, 6 females) who were tested at 10 ± 2.4 months after surgery participated in the current study and were compared to 10 subjects in the control group (5 males, 5 females). Subjects performed a jump-landing task and the landing was assessed using the Landing Error Scoring System (LESS) both before and after fatigue. Digital video camcorders recorded frontal and sagittal plane views of the subject performing the task. The LESS was scored using video replay. Psychological responses in the ACLR group were assessed with the ACL-RSI questionnaire. RESULTS: Patients after ACLR had a median LESS of 6.5 which reflects a poor result (LESS >6) in the pre-fatigue condition compared to controls who had a LESS of 2.5 which is considered excellent (≤4). In the post-fatigue condition, median LESS in patients after ACLR increased to 7.0 whereas in the control group the LESS increased to 6.0 both of which reflect a poor result. The median increase in LESS was larger in the control (2.0) group compared to patients after ACLR (1.0) but the difference was not significant (p=0.165). CONCLUSIONS: Patients after ACLR have higher LESS scores at baseline compared to a control group. Fatigue resulted in an increase in scores on the LESS in both groups. LEVEL OF EVIDENCE: 3b.

Return of normal gait as an outcome measurement in acl reconstructed patients. A systematic review.

BACKGROUND: Current clinical outcome measurements may overestimate the long term success of anterior cruciate ligament reconstruction (ACLR). There is a need to understand biomechanics of the knee joint during daily activities. This systematic review provides a comprehensive overview of the literature related to gait in patients following ACLR. The purpose of this systematic review was to investigate the available literature and provide a comprehensive overview of kinematic and kinetic variables that present during gait in patients after ACLR. METHODS: A literature search was performed in AMED, CINAHL, EMBASE, Medline and Scopus between January 2000 and October 2012. Inclusion criteria included articles written in English, German or Dutch, and those reporting on gait analysis in patients after ACLR. Kinematic and/or kinetic data of the uninjured and ACLR knee and healthy controls (CTRL) were outcome measurements of interest. Each study's methodological quality was assessed using the Critical Appraisal Skills Programme critical appraisal tool. RESULTS: Twenty two studies fulfilled the inclusion criteria. A total of 479 patients with a mean age of 27.3 were examined. Time between the injury and surgery and ranged from 3 weeks to 5.7 years. Gait analysis was done at a mean of 29.3 months after surgery. Gait was found to be altered in the sagittal, frontal and transverse planes after ACLR and may take months or years to normalize, if normalization occurs at all. CONCLUSION: Patients after ACLR have altered gait patterns that can persist for up to five years after surgery. It is imperative that rehabilitation techniques are examined in order to minimize changes in knee biomechanics during gait, as they have the potential to impact on the development of osteoarthritis. LEVEL OF EVIDENCE: 3a.