The patient was an 11-year-old boy who was referred to a physical therapist for a chief complaint of left anterior/lateral hip pain. Prior to referral to the physical therapist, radiographs were completed and interpreted as normal. Initially, his hip pain did not limit his participation in athletic activities; however, following a prescription of an exercise program, the patient reported worsening left hip pain that caused an inability to participate in lacrosse, as well as 2 episodes of severe night pain. The patient was immediately referred to his physician, where magnetic resonance imaging revealed signs most concerning for an infectious process/osteomyelitis in the region of the proximal femur and greater trochanter.

J Orthop Sports Phys Ther 2013;43(2):106. doi:10.2519/jospt.2013.0404

KEY WORDS: magnetic resonance imaging, osteomyelitis, radiography

STUDY DESIGN: Cross-sectional study. OBJECTIVES: To investigate the impact of quadriceps femoris (QF) muscle strength asymmetry at the time of return to sport on self-reported function and functional performance of individuals following anterior cruciate ligament reconstruction (ACLR). BACKGROUND: Evidence-based QF strength guidelines for return-to-sport decision making are lacking. Objective guidelines necessitate understanding the impact of QF strength deficits at the time of return to sport on function and performance. METHODS: Fifty-five individuals (mean age, 17.3 years) who were cleared for return to sport following primary ACLR (ACLR group) and 35 uninjured individuals (mean age, 17.0 years) in a control group participated in the study. QF strength (maximum voluntary isometric contraction) was assessed, and the quadriceps index (QI) was calculated [(involved strength/uninvolved strength) × 100%]. The ACLR group was further subdivided into 2 groups, based on the QI: high quadriceps (QI of 90% or greater) and low quadriceps (QI of less than 85%). The International Knee Documentation Committee Subjective Knee Evaluation Form score was used to assess self-reported function, and hop tests were used to assess functional performance. Multivariate analysis of variance and hierarchical regression analyses were performed. RESULTS: The individuals in the ACLR group were weaker, reported worse function, and performed worse on hop tests compared to those in the control group (P<.05). The low-quadriceps group demonstrated worse performance on the hop tests compared to the high-quadriceps group and the control group (P≤.016). Hop test performance did not differ between the high-quadriceps and control groups (P≥.14). QF strength predicted performance on the hop tests beyond graft type, presence of meniscus injury, knee pain, and knee symptoms. CONCLUSION: At the time of return to sport, individuals post-ACLR who had weaker QF (QI of less than 85%) demonstrated decreased function, whereas those with minimal QF strength deficits (QI of 90% or greater) demonstrated functional performance similar to uninjured individuals. QF strength deficits predicted hop test performance beyond the influences of graft type, presence of meniscus injury, knee pain, and knee symptoms.

J Orthop Sports Phys Ther 2012;42(9):750-759, Epub 19 July 2012. doi:10.2519/jospt.2012.4194

KEY WORDS: ACL, ACL reconstruction, function, hop test, knee, performance, weakness

The patient was a 34-year-old male recreational marathon runner referred to a physical therapist with a chief complaint of worsening right lateral hip pain of 3 months duration that was insidious in nature. Following a physical examination, the physical therapist discussed his suspicions with the referring physician. Magnetic resonance imaging revealed findings consistent with a stress fracture at the inferomedial right femoral neck, a mild cam-type deformity of the right femoral neck, and a mild degree of heterogeneity of the right superior anterior labrum, representing a possible tear.

J Orthop Sports Phys Ther 2011;41(11):905. doi:10.2519/jospt.2011.0423

KEY WORDS: hip, magnetic resonance imaging

STUDY DESIGN: Controlled laboratory, cross-sectional, cohort design. OBJECTIVE: To determine if a sex-specific pattern of lower limb asymmetries is present during a drop vertical jump (DVJ) maneuver at the time of return to sport after anterior cruciate ligament (ACL) reconstruction. BACKGROUND: A high incidence of second ACL injury is reported after reconstruction; however, the underlying mechanisms of this injury are unclear. While asymmetrical dynamic loading patterns predictive of primary ACL injury in healthy female athletes were observed in female athletes 2 years after ACL reconstruction, it is unknown if similar asymmetries are present in male athletes after ACL reconstruction at the time of return to sport. METHODS: A total of 98 participants were included in the study, 56 of whom had unilateral ACL reconstruction (35 female, 21 male) and had been released to return to unrestricted level 1 and 2 sports, and 42 of whom were uninjured, activity-matched control participants (29 female, 13 male). Lower extremity kinetic data were analyzed during a bilateral drop vertical jump maneuver from a 31-cm box. Peak vertical ground reaction force (VGRF) was calculated during the landing phase of the drop vertical jump and normalized to body weight (BW). A 2-by-2-by-2 analysis of variance was used to determine differences between side (involved versus uninvolved), group (ACL reconstruction versus control), and sex (female versus male) for the peak VGRF. RESULTS: A significant side-by-group interaction for peak VGRF (P = .002) was observed during the landing phase of the drop vertical jump in the entire cohort. The involved limb of the ACL reconstructed group displayed significantly lower VGRF (mean ± SD, 1.77 ± 0.35 BW) than the uninvolved limb (2.2 ± 0.4 BW, P<.001) and both the preferred limb (2.0 ± 0.4 BW, P = .002) and nonpreferred limb (2.09 ± 0.42 BW, P<.001) in the control group. No effect of sex was noted. CONCLUSION: After ACL reconstruction, both male and female participants at the time of return to sport demonstrated involved limb asymmetries in peak VGRF during landing from a bipedal task. These deficits, which persist at the time of return to sport, may increase the risk of future injury and indicate that rehabilitation after ACL reconstruction may require more targeted interventions to address involved limb biomechanical deficits in athletes of both sexes prior to return to sport participation.

J Orthop Sports Phys Ther 2011;41(8):553-559. doi:10.2519/jospt.2011.3591

KEY WORDS: ACL, drop vertical jump, female, male, vertical ground reaction force

STUDY DESIGN: Controlled cohort repeated-measures experimental design. OBJECTIVES: To determine if a neuromuscular training program (NMTP) focused on core stability and lower extremity strength would affect performance on the star excursion balance test (SEBT). We hypothesized that NMTP would improve SEBT performance in the experimental group and there would be no side-to-side differences in either group. BACKGROUND: The SEBT is a functional screening tool that is used to assess dynamic stability, monitor rehabilitation progress, assess deficits following an injury, and identify athletes at high risk for lower extremity injury. The SEBT requires lower extremity coordination, balance, flexibility, and strength. METHODS: Twenty uninjured female soccer players (13 experimental, 7 control) participated. Players trained together as a team, so group allocation was not randomized. The SEBT was administered prior to and following 8 weeks of NMTP in the experimental group and 8 weeks of no NMTP in the control group. A 3-way mixed-model ANOVA was used to determine the effect of group (experimental versus control), training (pretraining versus posttraining), and limb (right versus left). RESULTS: After participation in a NMTP, subjects demonstrated a significant improvement in the SEBT composite score (mean ± SD) on the right limb (pretraining, 96.4% ± 11.7%; posttraining, 104.6% ± 6.1%; P = .03) and the left limb (pretraining, 96.9% ± 10.1%; posttraining, 103.4% ± 8.0%; P = .04). The control group had no change on the SEBT composite score for the right (pretraining, 95.7% ± 5.2%; posttraining, 94.4% ± 5.2%; P = .15) or the left (97.4% ± 7.2%; 93.6% ± 5.0%; P = .09) limb. Further analysis identified significant improvement for the SEBT in the posterolateral direction on both the right (P = .008) and left (P = .040) limb and the posteromedial direction of the left limb (P = .028) in the experimental group. CONCLUSION: Female soccer players demonstrated an improved performance on the SEBT after NMTP that focused on core stability and lower extremity strength. LEVEL OF EVIDENCE: Performance enhancement, level 2b-.

J Orthop Sports Phys Ther 2010;40(9):551-558, Epub 6 August 2010. doi:10.2519/jospt.2010.3325

KEY WORDS: core stability, core strengthening, injury prevention training, trunk neuromuscular control

Study Design: Controlled single-group pretest/posttest design. Objective: The purpose of this study was to determine if a 6-week neuromuscular training program designed to decrease the incidence of anterior cruciate ligament (ACL) injuries would improve single-limb postural stability in young female athletes. We hypothesized neuromuscular training would result in an improvement in postural stability, with the greatest improvement taking place in the medial-lateral direction. Background: Balance training has become a common component of programs designed to prevent ACL injury. Rehabilitation programs can improve postural stability following ACL injury and reconstruction; however, there is limited information available which quantifies improvement of postural stability following neuromuscular training designed to prevent ACL injuries in a healthy population. Methods and Measures: Forty-one healthy female high school athletes (mean age, 15.3 years; age range, 13-17 years) participated in this study. Single-limb postural stability for both lower extremities was assessed with a Biodex Stability System. The neuromuscular training program consisted of three 90-minute training sessions per week for 6 weeks. Following the completion of the training program, each subject was re-evaluated to determine change in total, anterior-posterior, and medial-lateral single-limb stability. Two-way analysis of variance models were used to determine differences between pretraining and posttraining and between limbs. Results: The subjects showed a significant improvement in single-limb total stability (P = .004) and anterior-posterior stability (P = .001), but not medial-lateral stability (P = .650) for both the right and left lower extremity following training. In addition, the subjects demonstrated significantly better total postural stability on the right side as compared to the left (P = .026). Conclusions: A 6-week neuromuscular training program designed to decrease the incidence of ACL injuries improves objective measures of total and anterior-posterior single-limb postural stability in high school female athletes.

J Orthop Sports Phys Ther. 2004;34(6):305-316. doi:10.2519/jospt.2004.1325

Key Words: anterior cruciate ligament, balance, knee, prevention, proprioception

Traditionally, open kinetic chain rehabilitation and evaluation have been used as the primary tool to assess a patient's strength and readiness to progress to a higher functional level. More recently, closed kinetic chain activities have been developed and well documented as an alternate means to prepare and evaluate a patient's ability to return to a higher functional level. However, a dearth in recent literature comparing the correlation between an open kinetic chain isokinetic strength test and performance on a functional performance test exists. Therefore, the purpose of this study was to examine the relationship between a knee extensor strength and functional performance test, specifically the 1-legged hop for distance. Twenty subjects (x¯ = 20.7 years), with no prior history of lower extremity injury, participated in the study consisting of isokinetic evaluation of the quadriceps muscle using a Kinetic Communicator and a 1-legged hop for distance. Isokinetic testing was performed at 240°/sec. All tests were performed on the dominant and nondominant limbs. Pearson product moment correlation coefficients for peak torque and distance hopped were .78 for the dominant leg and .65 for the nondominant leg (p < .05). These results support the belief that isokinetic strength does not correlate strongly with functional tasks.

J Orthop Sports Phys Ther. 1995;22(5):202-206.

Key Words: functional testing, muscle strength, knee

Rehabilitation following anterior cruciate ligament (ACL) reconstruction has undergone a relatively rapid and global evolution over the past 25 years. However, there is an absence of standardized, objective criteria to accurately assess an athlete’s ability to progress through the end stages of rehabilitation and safe return to sport. Return-to-sport rehabilitation, progressed by quantitatively measured functional goals, may improve the athlete’s integration back into sport participation. The purpose of this clinical commentary is to introduce an example of a criteria-driven algorithm for progression through return-to-sport rehabilitation following ACL reconstruction. Our criteria-based protocol incorporates a dynamic assessment of baseline limb strength, patient-reported outcomes, functional knee stability, bilateral limb symmetry with functional tasks, postural control, power, endurance, agility, and technique with sport-specific tasks. Although this algorithm has limitations, it serves as a foundation to expand future evidence-based evaluation and to foster critical investigation into the development of objective measures to accurately determine readiness to safely return to sport following injury.

J Orthop Sports Phys Ther. 2006; 36(6):385-402. doi:10.2519/jospt.2006.2222

Key Words: anterior cruciate ligament, knee rehabilitation, lower extremity, sport injury