This week we discuss outcomes with femoroacetabular impingement syndrome FAIS), defined as "as a clinical triad of symptoms, signs, and imaging findings related to the underlying hip pathology." There are three bony morphologies associated with FAIS: cam, pincer, and mixed. Cam morpohlogy is a bony growth on the femoral head/neck, while a pincer morphology is bony growth of the acetabulum. Mixed morphology is the presence of both cam and pincer changes. Symptoms of FAIS include hip/groin pain, pain worse with motion or certain positions, clicking/locking/stiffness, decreased hip strength/ROM, and impaired balance. The FADDIR test, commonly associated with a clinical diagnosis of FAIS, actually has poor sensitivity and specificity (41% and 47%). Early activity modifications may be necessary to manage symptoms, which involves generally avoiding repetitive hip flexion and internal rotation and limiting end-range stretching of the hip, especially in the presence of pain. Studies also demonstrate hip muscle weakness in the presence of FAIS symptoms, which could be a focus of rehab interventions. Conservative management of FAIS for a minimum of 3 months has shown to be successful in 39-82% of FAIS cases, and it is likely successful conservative management is related to the radiographic severity of morphology. Most reviews demonstrate that surgery has improved short term outcomes (<1 year) compared to physical therapy in young, active populations. Although, the return to play rate after hip arthroscopy was 85.4%, which took an average of 6.6 months. One article found that 1 in 4 athletes don’t return to previous level of sport participation after hip arthroscopy for FAIS.

The abstract can be found here: https://pubmed.ncbi.nlm.nih.gov/37650998/

As always, if you enjoy what you hear, be sure to follow us on your favorite podcast platform and on Instagram @readingrehabpod. If you have any article recommendations be sure to send them our way!

This week we discuss considerations when utilizing the limb symmetry index (LSI) as a metric for return to sport testing following ACL reconstruction. Limb symmetry index is a popular metric which compares the performance of the involved limb to the uninvolved limb during a test. Commonly, a 90% threshold is used to determine if there is acceptable levels of asymmetry. However, there are a few points to consider when utilizing this metric. First, after an ACL rupture the contralateral side also loses strength and functional capacity. Therefore, comparing to the post-surgical performance of the uninvolved side can give an artificially inflated LSI, so it is important to ground the test outcomes in normative data or benchmark data. Second, variability in movement is a "hallmark of normal function" and understand humnas, and sport, are not always symmetrical. Although, an argument can be made that the test is to see if you have the capacity to be symmetrical, which does not mean you have to be symmetrical all the time, especially at submaximal efforts. Is your maximal effort symmetric on each side? If not, then you may be more likely to be hurt. Third, biomechanical asymmetries can persist past 9 months post ACLR, so don't just look at the numbers: look at the movement strategy. Finally, assess the functional capacity across a load continuum via testing considering the end goal as the sport.

The abstract can be found here: https://journals.lww.com/nsca-scj/abstract/2024/08000/testing_limb_symmetry_and_asymmetry_after_anterior.3.aspx

As always, if you enjoy what you hear, be sure to follow us on your favorite podcast platform and on Instagram @readingrehabpod. If you have any article recommendations be sure to send them our way!

This week we discuss microscopic changes to muscle architecture following eccentric hamstring exercise. Twelve recreationally active participants in their mid-20s performed 9 weeks of eccentric hamstring training via Nordics: 3 session per week, progressively building from 4x6 to 5x8 at the end. After the 9 weeks of training, they had a 3 week detraining period. Eccentric hamstring strength during Nordics, passive fascicle length, and sarcomere length were measured at baseline, end of training, and end of detraining. Serial sarcomere number was calculated using fascicle length and sarcomere length. After the training block, there was significantly increased biceps femoris fascicle length, serial sarcomere number, volume, and knee flexion torque. There was a large effect for all of these metrics. There was a significant regional effect for fascicle length and serial sarcomere number: increased fascicle length at distal region compared to central, but increased serial sarcomeres centrally versus distally. During detraining, fascicle length decreased but remained logner than pre-training lengths. Muscle volume stayed the same and there was a decrease in strength but it was higher than pre-training. Takeaways from this article include evidence for a long-term adaptation of eccentric training being addition of sarcomeres in series which could be protective against hamstring strain injuries, and muscle architectural responses to detraining happen quickly! It would be interesting to investigate if addition of sarcomeres in series is an effect specific to eccentric training, or any specific hamstring muscle training would create this effect.

The abstract can be found here: https://pubmed.ncbi.nlm.nih.gov/39461588/

As always, if you enjoy what you hear, be sure to follow us on your favorite podcast platform and on Instagram @readingrehabpod. If you have any article recommendations be sure to send them our way!