DNS for Femoroacetabular Impingement

Dynamic Neuromuscular Stabilization Applied to Anterior Acetabulofemoral (Hip) Impingement


The patient (a physiotherapist) in this video reports chronic anterior hip pain, unresponsive to previous conservative care. He reports the classic signs and symptoms of anterior hip impingement - pain localized to the anterior hip that is provoked by activities that require hip flexion and internal rotation.

Examination reveals marked limitation of hip flexion and hip internal rotation with pain localized to the anterior hip. We do not have imaging, and given chronicity of the complaint I would recommend he get standard x-rays of the hip to assess for CAM or pincer deformity; these findings and the severity of them will alter our prognosis, i.e. if there is a large CAM and/or pincer deformity we are not likely restore full pain free hip flexion-adduction-internal rotation. There may be an anterior labral tear; there may be iliopsoas tendinopathy and bursitis. Given the nature of the presenting complaint I’d suggest all are likely. 

Regardless of the patho-anatomical diagnosis the goals of rehabilitation remain the same – to improve quality of life through improved function and reduced pain with activities of daily living. We have lots of therapeutic options here and the intent of this article is not to review them all, just to review one of the most effective options, namely the 7 month side-sit and quadruped position as introduced by Pavel Kolar et al in Dynamic Neuromuscular Stabilization courses.

Preface: For those unfamiliar with postural ontogenesis and developmental kinesiology, I should clarify the language used in “7 month side sit”. DNS or Dynamic Neuromuscular Stabilization is a strategy of rehabilitation based on postural ontogenesis and developmental kinesiology. “7 months” refers to the posture that a baby can ideally achieve by 7 months. At 7 months an ideally developing baby can roll from supine to side support and upright onto the elbow-forearm to the position formally known as the immature oblique sit or 7 month side sit. They are not yet able to raise up onto the hand, but, they can support on the elbow-forearm with the support zones in lower extremity being the posterior to lateral gluteal fascia / hip toward lateral condyle of the femur.  Note that the intention is always to move toward something, i.e. Mom/Dad, a toy, etc.

The immature and mature oblique sit exercises facilitate eccentric loading of the hip external rotators and abductors with well coordinated activity of the hip internal rotators / adductors to facilitate ideal hip kinematics, effectively reducing the pain of anterior impingement in previously painful positions.  Of course there are many ways to lengthen and relax the hip external rotators and abductors. Mulligan Mobilizations with Movement, or belt assisted end range of motion mobilizations for hip flexion, adduction, and internal rotation are excellent options to accomplish this goal. You can combine Progressive Angular Isometric Loading (PAILs) and Regressive Angular Isometric Loading (RAILs) contractions into your end range mobilization to retrain neuromuscular control and regain strength in these positions. ALL GOOD! 

The beauty however of the immature and mature oblique sitting positions is the requirement for the person to control the trunk and pelvis over shoulder and hip. The patient’s ability to control the pelvis on hip is after all an essential component to any weight-bearing exercise and therefore an essential component of rehabilitation. It is not sufficient nor is it wise to retrain the hip function with concentrically biased exercises. The clam shell and side lying leg raise exercises that we perform with our patients are excellent at improving endurance and/or promoting blood flow to the hip external rotators and abductors; we can add resistance to them and perhaps call them “strengthening” exercises as well. These exercises have also been shown to facilitate the gluteal muscles. Although in some contexts this can be a good thing, in the presence of pain we often see shortening of the hip external rotators, or better stated the inability for the external hip rotators and gluteal muscles to eccentrically stabilize the hip (which is essential). Aside from very rudimentary neuromuscular coordination, these exercises will not retrain the pattern of loading or activity required to differentiate and stabilize the pelvis on hip in a closed kinetic chain. 

The 7 Month Side Sit – Set Up

Position the patient in a side support on elbow/forearm and gluteal fascia with downside hip in 80-90 of hip flexion. Rest the top leg in a comfortable position behind the bottom leg. Start by ensuring ideal alignment of trunk on pelvis, thorax on scapulae. The axis of the rib cage and pelvis should be parallel to each other; inferior anterior ribs in a position of expiration; the breathing pattern should result in three dimensional filling of the abdominal wall posteriorly to inferiorly and anteriorly with lateral anterior expansion of the thorax (not superior migration or elevation of ribs). The spine is long and relaxed. 

The movement

Initiate support through the downside lateral femoral condyle and initiate turning or rotation of the pelvis and trunk over the downside hip. It can be helpful to place your hand under on the lateral knee with subtle to significant medial superior force to encourage appropriate support. Ensure that the patient does not sink toward the table while turning and encourage strong support through the elbow, forearm and downside hip through femur.  Do not move into pain; find the edge of discomfort and back off slightly. From a pain free position we have lots of options:

Load the pattern be resisting it, placing hand on ASIS and asking patient to “pull” pelvis over into rotation while not allowing further rotation; 
Facilitate it by pushing the pelvis over the downside hip while the patient resists the rotation. 
You can also do as I did in the video, which is to encourage uprighting and rotation of the pelvis over femur, following through with the reaching movement. 

Most often I am performing all three of these options within one session, with the initial intent being to teach the patient how to create appropriate support with rotational control, with the goal being to perform the full pattern pain free. An advanced version would have the patient stepping forward with the “swing” leg such that both upper and lower extremity are performing the stepping forward function in an ipsilateral pattern. Regardless of the variation performed, as we saw in this patient this technique often results in impressive changes in ROM and function.

(note: in video I stated “5 month” side support… that was a brain fart; 5 month is side lying and on elbow is 7 month)