The previous article
touched upon hip Oa and muscles which may be weak and strong allowing for more specific rehabilitation.
In addition to muscle imbalance, are there particular postures that a person adopts that aggravates the disease process? OA can affect all joints and where a lot has been said about arthiritic knees in this domain, there has not been much written regarding OA and the hip. The purpose of this article aims to briefly discuss Hip Oa and associated postures that may progress the disease process. Hip anatomy
The hip joint consists of the articulating surfaces between the symmetrical socket known as the acetabulum (of the pelvis) and the femur (thigh bone). The acetabulum is deepened by a cartilage-covered ring of fibrocartilage known as the labrum to aid in the congruency of the joint. The joint space between the acetabulum and femur are at equal points throughout, to allow adequate lubrication.
The hip joint relies heavily on surrounding capsule, ligaments (transverse, iliofemoral, pubofemoral, and ischiofemoral ligaments) and muscles to maintain it stability. Hip osteoarthritis
Essentially the disease process affects the cartilage that surrounds the joint and thus exposes the bone reducing the joint space and allowing for bone and bone contact. Hip osteoarthritis is something that affects people more commonly over the age of 50 and is exacerbated by obesity, previous hip fractures, congenital conditions and genetic predispositions. Symptoms
Arthritic hips can be very varied and transient depending on factors such as a weather. Main symptoms include:
Pain with weight bearing activities Limited range of motion Stiffness of the hip Walking with a limp Referred pain into the bottom and groin Postural habits
In a clinical setting a patient will tend to stand in a way they deem is “good posture” for the benefit of the assessing therapist. This is all well and good and provides the therapist an idea of that patient's perception and awareness of posture; However another important consideration is what posture that patient assumes during prolonged standing, or in relaxed postures in their normal environment. When looking at the hip joint, one must consider negative postures like “hanging on the hips” where the weight is shifted to one side (e.g the right) and the opposing pelvis (i.e the left) is dropped down into relative adduction. If this hip (left) is in increased adduction (shortened adductors), by default of muscles working in pairs and as opposites, the abductors on the left will be stretched (lengthened). Also in such stances, the ITB is in tension and muscle activity on the left is reduced. These are postures that are often observed by clinicians when assessing the single leg stance of patient with hip OA.
The problem with adopting such a pose is, it may lead to a phenomenon termed ‘stretch weakness’ occurring in these hip abductor muscles on the left resulting in inner range weakness. What this suggests is ‘hanging on the hip’ in adduction, where hip abductors are lengthened, overtime may actually lead to physiological changes making the muscle weaker.
Clinically this proposes that testing and strengthening hip abductors ought to be done with the leg in adduction (10 degrees) as well as in neutral to gain the most therapeutic benefit for OA patients. Interestingly there has been research suggesting that weight bearing with excessive hip adduction will also result in increased joint forces and this had been found in patients with early hip joint pathology during the stance phase of gait. Further highlighting the importance to reduce adduction and increase abduction strength. In addition to increasing the load through the joint, excessive hip adduction also has the effect of increasing the compressive load of the ITB over the greater trochanter, into which the glut. medius tendon inserts. Therefore prolonged standing in the "hanging on the hips" posture produces a significant amount of compressive loading of the glut. medius tendon and therefore possible dysfunction. Other negative postures that produce the above effects include sitting cross-legged in hip adduction, and sleeping in sidelying in hip and patients with occupations requiring prolonged standing must be correctly advised and rehabilitated. Treatment for such clients should not only look at strengthening the abductor muscles at different ranges, as already discussed but also to educate the patient about these postures to avoid lengthening the abductors and compressive loading of the ITB and Glut. medius tendon. References:
Grimaldi, A (2009)Assessing lateral stability of the hip and pelvis, Physiotec Physiotherapy, Manual Therapy:16 (2011) 26-32