The knee is a dumb joint...
At least according to the evidence presented by Dr. Scott Greenberg, DPT, BSC, CPed, CSCS and his peers of the University of Florida Sports Performance Center.
Dr. Greenberg was one of the hosts of the world-class faculty at the Running Medicine Clinic at the Orthopedics and Sports Medicine Clinic in Gainesville, Florida on February 11th-12th, 2010.
Dr. Greenberg presented evidence that described the knee as an often painful, weak link between the ankle and the hip.
The course was presented by Course Director Kevin Vincent, MD, PhD and featured guest speaker Francis G. O'Connor, MD, MPH, COL, MC, USA.
Dr. O'Conner is the author of The Textbook of Running Medicine and the Medical Director of the Marine Corps Marathon. Dr. O'Conner also happens to be active duty Marines and just finished a tour of duty in the Middle East, caring for US Navy SEALS.
The UF running conference is an annual occurrence timed to coincide with the Five Points of Life Gainesville Marathon.
The course content was largely consistent with a surge of evidence arguing that knee pathology is often driven by hip and ankle dysfunction. Some of the most recent evidence was published, coincidently, in the February Journal of Orthopedic and Sports Physical Therapy.
Christopher Powers' PT, PhD Clinical Commentary article presents compelling data on hip biomechanics that summarizes the kinematic and kinetic data to date and may change common practice patterns for knee rehab.
View Dr. Powers slideshow on knee and hip kinematics here (JOSPT log-in required).
Two ways to move the knee
Non-weightbearing: This image is an example of the dysfunctional lateral movement of the patella in non-weightbearing (like on a knee extension machine). In this image the mobile patella is pulled laterally on a stable femur.
Weightbearing: Dr. Powers' article also describes lateral patella movement in weightbearing (like a single leg squat) where the mobile femur internally rotates under the stabilized patella.
Excessive hip internal rotation and adduction seem to be some of the most persuasive drivers behind common, high-volume conditions seen by physical therapists involving the knee.
Interestingly, Dr. Powers article presents some conflicting data: isometric assessment of hip muscle force producing capacity (strength) correlates poorly with the expected data on hip kinematics. One possible source for this conflict is the high rate of measurement error with isometric muscle testing (eg: MMT).
If hip kinematics are the main drivers behind anterior knee pain then that explains the poor outcomes of arthroscopic knee surgery in two randomized , controlled trials from 2008 and 2002.
We've known for ten years (at least) the value of non-operative treatments to the hip, knee and ankle for primary knee pain.
Runners are just one of the many niche groups that benefit from the 'functional' physical therapy diagnosis.
The knee is a dumb joint but a smart example of how physical therapist diagnosis can improve outcomes and decrease health care costs.
Rabu, 17 Februari 2010
The knee is a dumb joint...