Examination of the pelvis and the hip
For the initial medical examination no specific equipment is necessary unless the patient’s condition is so severe to require emergency care and resuscitation. The patient’s part of the body of interest should be uncovered and all other parts of the body gowned prior to medical examination. Some critical elements of the investigation such as testing for limb movement may not be applicable if a fracture is suspected. For any musculoskeletal pathology it is essential to have a thorough understanding of the anatomy, as the examination will assess differences to normal structures and functions. It is necessary to acquire information on pre-existing conditions or trauma, including the mechanisms of injury, changes in motility and function, swelling and received treatments. A clear description of current symptoms must be provided to the examiner.
Prompt assessment of injuries or degenerative conditions to the pelvis and hip are critical. Traumatic injuries in this highly vascularised region where important organs reside can become life threatening. Similarly, chronic pathologies to the pelvis and hip can severely compromise ambulation and affect the quality of life and ability to work. Medical examination of the pelvis and hip focuses on establishing accurately the exact pathology in order to develop an optimal therapeutic plan. Examination is also the key to impairment assessment to determine the impact of the pathology on the overall impairment of the patient, including the ability to return to work.
Important landmarks of the pelvis and the hip
Anatomical landmarks represent a guide in the examination of the specific region of the body that may be compromised by injury or degenerative conditions. In the pelvis and hip, there are bony and soft tissue landmarks. The bony landmarks are the edges of bones that are easily identifiable with palpation whereas the soft tissue landmarks include a variety of tissues, vessels and nerves.
Bony landmarks
Pubic symphysis
Anterior superior iliac spine
Iliac crest
Greater trochanter of the femur
Ischial spine
Ischial tuberosity
Coccyx
Inspection
For general inspection, the patient is in a standing position with minimal clothing and no shoes. The examiner aims to detect any changes in the appearance such as muscle wasting, scars, Deformities, Contractures, Differences in leg length, Ability to stand, Pelvic obliquity (asymmetry of the iliac crests), Discrepancy in leg length. Other criteria for detecting any anatomical changes of the pelvis and hip are:
Bryant’s triangle
The Bryant’s triangle is useful for the examination of the hip. It is an imaginary triangle formed by a horizontal line at the level of the anterior-superior iliac spine (ASIS) and a vertical line through the greater trochanter at a 90° angle.
If the distance between the greater trochanter and the ASIS is smaller than 5 cm, it indicates pathology of the femoral neck, possibly a fracture.
Palpation
Palpating the bony landmarks of the pelvis including the iliac spine and the great trochanter of the femoral bone assists in detecting pelvic obliquity due to leg length difference. If differences persist in spite of manual repositioning of the pelvis further tests are required as described below:
Flexion Contracture
Hip held in flexion
Knee in flexion
Hyperlordosis at the lumbar spine
Pelvic Obliquity (tilting of the pelvis)
Functional Scoliosis
External Rotation – Often seen in osteoarthritis to help relieve pain by increasing the joint space.
Muscles – Look for wasting of gluteal muscles
Range of movement of the hip
To ascertain the function of the hip, the patient is asked to perform some tests to assess changes in the range of movement, joint instability and pain level. During the examination it is critical to monitor the non-injured region of the body to achieve an overall functional status of the patient.
If abnormalities are detected, the examiner will perform passive tests to measure increased or impaired range of movements. Subsequently, specific instability tests will follow to identify the exact underlying pathology. Based on individual tests, normal range of movement of the hip is:
Flexion – from 0° to 100°- 135° in a spine position with knee flexed.
Extension
from 0° to 15°- 30° in a prone position with knee flexed or straight
Abduction
from 0° to 40°- 45° in a supine position
Adduction
abnormal if angle between transverse axis of pelvis and limb is < 90°
External Rotation
from 0° to 40°- 60° in a supine position
Internal Rotation
from 0° to 30°- 40° in a spine position
These movements can be done with either straight or flexed knees.
Thomas’ test
Named after Dr Hugh Owen Thomas, this test is used for assessment of hip flexion contracture. The test consists of three steps.
The patient lays in a supine position. The examiner places the hand under the lumbar spine to identify lumbar lordosis.
The healthy hip is flexed towards the chest to obliterate the lumbar lordosis.
Measure the angle between the thigh of the pathologic hip side and the table to detect a flexion deformity of the hip.
This test reveals possible:
Pelvic obliquity (tilting of the pelvis)
Functional scoliosis
External rotation – e.g. in osteoarthritis to relieve pain by increasing the joint space
Muscles wasting of the glutei
Femoral nerve tension test
This is an alternative to the stretch test above for the impingement of the femoral nerve root. The patient lies prone and the examiner passively flexes the knee completely. The test is positive when a sharp pain is felt at the inguinal area, thigh, buttocks or lumbar spine.
Vascular tests
Following an injury to the pelvis and hip a comprehensive neurologic and vascular should be performed to detect any damage that may compromise blood flow and neural function of the limbs. For common vascular testing, the patient pulses are taken in various regions of the limb from the inguinal area to the foot. Testing is repeated after surgical intervention to exclude any damage caused intraoperatively.
There are multiple pulses
Femoral pulse at the groin
Popliteal pulse at the popliteal fossa with leg partially flexed
Posterior tibial pulse on the back of the knee
Anterior tibial pulse just above the inner ankle
The Ankle–Brachial Index (ABI)
The ankle-brachial index is a more precise measure of blood perfusion in the lower limbs compared to a simple pulse. The ABI index is calculated as the ratio of systolic blood pressure in the lower legs (ankle) and systolic blood pressure in the arms. A blockage of the limb arteries is suspected with lower blood pressure in the limb. If the ABI ratio is less than 0.9, it is recommended to perform an arteriography and consult a vascular surgeon.
Trendelenburg test
This test is used to investigate abductor function in patients with suspected hip dislocation. While the examiner is facing the patient, the patient stands upright on one leg, keeping the opposite leg with the hip and knee flexed at 90°.
In healthy patients the pelvic crests remain on the same level. However, when the pelvis is inclined towards the elevated leg it may indicate neurological dysfunction of the abductor muscles or hip dislocation and hip fracture.
Gait test
With an underlying pathology of the hip the gait pattern is usually altered. These changes are a compensatory reaction to pain of the affected side generating an asymmetric gait pattern and a limp. Major gait alterations are:
Antalgic gait (alleviating pain): more time is spent on the healthy side compared to the pathologic side. This results in a shortened stride length (stance phase) for the contra lateral limb and an increased/double support time
Short leg gait: consists in evident shift of the body from the centre of gravity towards the shorter limb. The stance phase is of equal length on both sides
Trendelenburg gait: drop of the pelvis on the contralateral side of the stance leg
Gluteus maximus gait: weakness of the gluteus maximus (muscle hip extensor) is compensated with a forward thrust of the pelvis and a backwards thrust of the upper body.
Leg measurement tests
Measurement of leg length discrepancy is important to improve gait abnormalities, which over time can be detrimental to the hip and spine. A leg length inequality of 2 cm or less can be compensated with a shoe lift. However, leg length inequalities beyond 5 cm are functionally a problem and require a solution such as foot-in-foot prosthesis. Different methods are available for leg length measurement:
Exact (real) measurement is taken from the centre of the femoral head to the inner or medial malleolus at the tibial bone while the patient lies in a supine position
Apparent method is measured from a midline point of the body (umbilicus, xiphisternum (or lower sternum)) to the medial malleolus (less accurate)
If the lower leg is shorter, the measurement is taken from the knee to the heel with both legs bent and the feet touching the table
Teleroentgenogram is a single antero-posterior X-ray of the lower extremity with an integrated ruler
Orthoradiography involves three X-ray exposures (hip, knee and ankle)
Scanography is similar to orthoradiography but the exposure size is reduced to obtain all three exposures on one film
Computer tomogram (CT) is increasingly used as it relies on less radiation and is more accurate than conventional radiographic techniques for leg length measurement
Ely’s test
This test reveals tightness of the rectus muscle due to rectus femoris contracture. With the patient in a prone position, the knee is passively bent towards the glutei. The test is positive when the patient raises the hip from the examination bed.
Ober’s test
This test shows tightness due to a contracture of the ilio-tibial band or fasciae latae of the lateral thigh. With the patient lying on the healthy side, the hip is passively extended and abducted. The test is positive when the leg remains abducted and is unable to return to neutral or adducted position.
Apprehension test
This test is used to diagnose labral pathology of the hip with the patient in a supine position. The examiner passively flexes the patient’s knee and gently abducts the hip with an external rotation. The test is positive if this movement triggers pain at the hip, which may suggest a labral tear. The additional hip apprehension test is done with the patient supine and the knee bent at the edge of the table and the leg hanging free. When the leg is extended and externally rotated the patients feels pain at the hip.
Tripod sign
Tripod sign is used to determine tightness in the hamstrings. The patient sits with the knees flexed at 90°. The examiner passively extends the knee completely. The test is positive when this movement forces the patient to lean back. This is caused by hip extension and requires arms support. (Differential Diagnosis sciatica)
Phelps test
Phelps test is used to detect a tight gracilis muscle. The patient lies in a prone position with the knees fully extended and the examiner passively abducts the hips. This is repeated with the knee flexed. The test is positive if hip abduction is too large.
Piriformis syndrome test
This test consists in the compression of the sciatic nerve on the posterior thigh along the piriformis muscle. The patient lies on the side with a stabilised pelvis while keeping the hip flexed at 45° and the knee at 90°. The examiner rotates the hip internally. This test is positive if this movement triggers sciatic pain.
Femoral nerve stretch test
This tests is used to diagnose femoral nerve root impingement. It consists in the patient lying on the side and passively extending the leg at the hip with the knee bent at 90°. If pain, numbness or tingling is felt on the anterior or lateral thigh, the test is positive.