The hip joint is a “ball and socket” joint. The head of the thigh bone makes up the ball portion and the “socket” is made up by the cup shaped acetabulum of the pelvic bone.
A smooth articular cartilage covers the bone ends to allow pain free motion in the joint. Normally, the hip joint allows movements such as flexion, extension, abduction, adduction, internal and external rotation including circumduction.
Hip joint is a weight-bearing joint and prone to damage by wear and tear, sports injury, motor vehicle accidents, degenerative disease or major falls. In all these cases you can experience pain and functional limitation. Hip pain is usually felt in the groin region but can also be experienced in front of the thigh, the knee and buttocks. Therefore it is essential for your doctor to assess the exact cause for the pain to treat accordingly.
During the physical examination your doctor collects information about your symptoms and activity restrictions such as how long and how far you can manage to walk without walking aids. Then your doctor starts the physical examination by examining your gait. You will be asked to take a few steps forward and come back during which the symmetry of your gait will be observed.
General inspection is done while you are in a standing position. Your doctor observes from the front to check your posture, the position of your shoulders, and for signs of muscle wasting. Observation from the side is done to check for body inclination and from the back, for abnormal curvature of spine.
The doctor measures the leg lengths and also examines the area for scars and sinuses around the hip joint. Leg length measurements are taken with you lying on the table with both legs fully stretched out. Your doctor measures the length from the umbilicus to the medial malleolus. If leg lengths vary, an additional examination, block testing, is done for confirmation. For this examination the shorter leg is raised using blocks with your feet flat on the floor and until pelvis is level.
The next step in a physical examination of the hip is palpation or feeling for abnormalities and tenderness in the joint. Certain hip conditions can be distinguished by eliciting tenderness while palpating in a particular area of the joint. Tenderness in the greater trochanter region hints at the possibility of trochanteric bursitis and tenderness over the lesser trochanter suggests a muscle strain caused by sports injury.
The movements of the hip joint are tested passively by your doctor. Flexion of the hip is tested by keeping the left hand under the lower back and checking for the range of flexion in each hip at a time. The normal range of flexion is from neutral position to 120 degrees.
To test for abduction and adduction, the left hand is placed on the opposite iliac crest in order to stabilize the pelvis and with the right hand the extended leg is abducted until a tilting of the pelvis is felt. The normal range is 45 degrees. Similarly, adduction will be tested by crossing over the leg and moving it medially. The normal range of movement is 25 degrees.
Internal and external rotational movement is tested by maintaining the leg in fully extended position and rolling the leg over the table. The foot indicates the range of rotation. Rotation is also tested with 90 degrees of knee flexion. The leg is moved medially to check for external rotation and also moved laterally to check for internal rotation. The normal range for each movement is 45 degrees.
For assessing range of hip extension of the hip, you must lie on the table in the face down position. Your doctor holds the left hand over the sacrum to detect any movement and gently lift up your legs, one at a time. The normal range varies from the neutral position to 20 degrees of extension.
In addition to the above mentioned tests, your doctor may perform some special tests for diagnosing certain conditions. These special tests include:
Trendelenburg’s Test: For this test, you will stand on one leg for about 30 seconds and then alternate legs. In normal conditions, the position of the iliac crest remains unaltered regardless of the leg lifted. However, if the iliac crest inclines to one side when the leg is lifted, it suggests an abnormality or weak hip abduction.
Thomas’s Test: Thomas’s test is contraindicated in patients with hip replacement because of the risk of dislocation. This test is performed to check for fixed flexion deformity of the hip joint. While lying down on an examination table, your doctor places his hand under your lower back and bends the leg opposite the hip being tested up to the chest. The hip joint on the non-test side is then examined. If this leg is raised off the table and there is inability to completely extend the joint the test is positive for fixed flexion deformity.
Physical examination of the hip joint is a necessary assessment tool in the detection of hip joint disorders. An attentive and orderly method of examination helps your doctor to prepare a proper treatment plan.