The relationship between performance on the modified star excursion balance test and the knee muscle strength before and after anterior cruciate ligament reconstruction.

OBJECTIVES: The objective of this study was to evaluate the dynamic balance of the injured and uninjured limb before and after the anterior cruciate ligament (ACL) reconstruction and compare with the control group. STUDY DESIGN: Prospective longitudinal. SETTING: Biomechanics laboratory. PARTICIPANTS: Participants are 24 males (mean age, 27.5 years) with unilateral ACL injury (ACLG) and 24 male healthy volunteers (CG). MAIN OUTCOMES MEASURES: The modified star excursion balance test (SEBT) and isokinetic knee extensor and flexor strength were applied in the ACLG preoperatively and after surgery. The dominant limb of CG was evaluated at a single time. RESULTS: There was no difference between the injured and the uninjured limb of the ACLG (P > 0.05) before and after surgery. Preoperatively, both ACLG limbs had a significantly lower reach distance in posteromedial (PM) and posterolateral (PL) directions and in composite reach (CR) score compared to the control group (P < 0.001). Postoperatively, no significant differences were found between ACLG and CG (P > 0.05). There was a positive correlation between preoperative PL (0.59) and CR (0.51), postoperative PM (0.36), PL (0.36) and CR (0.46) with flexor strength at 12 months after surgery. CONCLUSION: Patients with ACL injury presented a worse performance in the SEBT in the preoperative period compared to the control group. After ligament reconstruction, the performance in the SEBT became equivalent to that of the control group. The strong correlation between flexor strength and posterior directions of the injured limb demonstrates the importance of the knee flexor muscles in the neuromuscular control of patients submitted to ACL reconstruction.

Relationship among eccentric hip and knee torques, symptom severity and functional capacity in females with patellofemoral pain syndrome.

OBJECTIVE: To determine the relationships between eccentric hip and knee torques, symptom severity and functional capacity in females with patellofemoral pain syndrome (PFPS). DESIGN: Within-subject correlational study. SETTING: University biomechanics laboratory. PARTICIPANTS: 10 females diagnosed with PFPS. MAIN OUTCOME MEASURES: Eccentric strength of the hip abductors and lateral rotators, and knee extensors were assessed using an isokinetic dynamometer. A 10-cm visual analog scale was used to determine usual knee pain in the last week. The Anterior Knee Pain Scale (AKPS) was used to determine the functional capacity of the patients. RESULTS: The study found that the greater the eccentric knee extensor and hip lateral rotator torques, the higher the functional capacity of the patients (p = 0.02, r = 0.72; p = 0.02, r = 0.72). It was also shown that the greater hip lateral rotator torque, the less the usual pain reported in the last week (p = 0.004, r = -0.84). Despite the lack of statistical significance (p = 0.11), it was also found a modest negative relationship between the eccentric knee extensor torque and the usual pain reported in the last week (r = -0.56) that was considered clinically meaningful (d = 1.4). CONCLUSIONS: This study showed that eccentric knee extensor and hip lateral rotator torques were associated with functional capacity and pain level in females with PFPS. Further investigations should be carried out to verify the effects of an intervention program focused on the eccentric action of these muscles with respect to the symptoms in patients with PFPS.

Eccentric hip muscle function in females with and without patellofemoral pain syndrome.

CONTEXT: Patellofemoral pain syndrome (PFPS) is a common knee condition in athletes. Recently, researchers have indicated that factors proximal to the knee, including hip muscle weakness and motor control impairment, contribute to the development of PFPS. However, no investigators have evaluated eccentric hip muscle function in people with PFPS. OBJECTIVE: To compare the eccentric hip muscle function between females with PFPS and a female control group. DESIGN: Cross-sectional study. SETTING: Musculoskeletal laboratory. PATIENTS OR OTHER PARTICIPANTS: two groups of females were studied: a group with PFPS (n = 10) and a group with no history of lower extremity injury or surgery (n = 10). INTERVENTION(S): Eccentric torque of the hip musculature was evaluated on an isokinetic dynamometer. MAIN OUTCOME MEASURE(S): Eccentric hip abduction, adduction, and external and internal rotation peak torque were measured and expressed as a percentage of body mass (Nm/kg x 100). We also evaluated eccentric hip adduction to abduction and internal to external rotation torque ratios. The peak torque value of 5 maximal eccentric contractions was used for calculation. Two-tailed, independent-samples t tests were used to compare torque results between groups. RESULTS: Participants with PFPS exhibited much lower eccentric hip abduction (t(18) = -2.917, P = .008) and adduction (t(18) = -2.764, P = .009) peak torque values than did their healthy counterparts. No differences in eccentric hip external (t(18) = 0.45, P = .96) or internal (t(18) = -0.742, P = .47) rotation peak torque values were detected between the groups. The eccentric hip adduction to abduction torque ratio was much higher in the PFPS group than in the control group (t(18) = 2.113, P = .04), but we found no difference in the eccentric hip internal to external rotation torque ratios between the 2 groups (t(18) = -0.932, P = .36). CONCLUSIONS: Participants with PFPS demonstrated lower eccentric hip abduction and adduction peak torque and higher eccentric adduction to abduction torque ratios when compared with control participants. Thus, clinicians should consider eccentric hip abduction strengthening exercises when developing rehabilitation programs for females with PFPS.

The effect of additional strengthening of hip abductor and lateral rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot study.

OBJECTIVES: To study the effect of additional strengthening of hip abductor and lateral rotator muscles in a strengthening quadriceps exercise rehabilitation programme for patients with the patellofemoral pain syndrome. DESIGN: Randomized controlled pilot trial. SETTING: Clinical setting with home programme. PARTICIPANTS: Fourteen patients with patellofemoral pain syndrome. INTERVENTION: The subjects were randomly assigned to the intervention group (strengthening of quadriceps plus strengthening of hip abductor and lateral rotator muscles) or to the control group (strengthening of quadriceps). Both groups participated in a six-week home exercise protocol. MAIN OUTCOME MEASURES: The perceived pain symptoms, isokinetic eccentric knee extensor, hip abductor and lateral rotator torques and the gluteus medius electromyographic activity were assessed before and after treatment. Parametric and non-parametric tests were used to compare the groups before and after treatment with alpha=0.05. RESULTS: Only the intervention group improved perceived pain symptoms during functional activities (P=0.02-0.04) and also increased their gluteus medius electromyographic activity during isometric voluntary contraction (P=0.03). Eccentric knee extensors torque increased in both groups (P=0.04 and P=0.02). There was no statistically significant difference in the hip muscles torque in either group. CONCLUSION: Supplementation of strengthening of hip abductor and lateral rotator muscles in a strengthening quadriceps exercise programme provided additional benefits with respect to the perceived pain symptoms during functional activities in patients with patellofemoral pain syndrome after six weeks of treatment.

A abordagem funcional dos músculos do quadril no tratamento da síndrome da dor femoro-patelar / Hip muscle's functional approach in the of patellofemoral pain syndrome treatment

A Síndrome da dor femoro-patelar(SDFP) é uma das afecções mais comuns da articulação do joelho. Recentemente, tem-se dado atenção ao fortalecimento e treino funcional da musculatura do quadril no tratamento da SDFP. O objetivo desta revisão foi discutir a função dos músculos do quadril na manifestação e no tratamento da SDFP. Foram encontradas evidências de alterações na função dos músculos abdutores e rotadores laterais do quadril em indivíduos com SDFP quando comparados a indivíduos saudáveis. Os estudos de tratamento da SDFP encontrados, com ênfase na musculkatura do quadril, demonstraram sucesso no tratamento. Assim, a fraqueza e o retardo no tempo de ativação da musculatura do quadril parecem contribuir para a manifestação da SDFP e devem ser consideradas na avaliação e tratamento dos pacientes portadores da SDFP. Estudos com melhor qualidade metodológica são necessários para definir qual a melhor abordagem de tratamento para a melhora funcional e da sintomatologia dolorosa nos pacientes com estas alterações.