Musculoskeletal assessment

CHAPTER 10 Musculoskeletal assessment

Section 10A Orthopaedic assessment of the lower limb


A thorough musculoskeletal assessment of the whole limb is an essential component of evaluation of a patient’s specific and often localised lower limb complaint. Apparent localised foot and ankle problems may have a genesis in proximal regions or, conversely, have secondary untoward effects on other structures. Such an assessment involves both static and dynamic assessment of musculoskeletal function.

Movement of the lower limb involves interaction between the musculoskeletal and nervous systems. The function of both systems can be compromised by vascular pathology. This chapter concentrates on the orthopaedic assessment of the musculoskeletal system. The assessment of the vascular system is covered in Chapter 6 and the neurological basis of movement and assessment of the nervous system are covered in Chapter 7. As the healthcare practitioner becomes competent, experienced and confident, essential components of these three systems will be evaluated seamlessly during the patient evaluation. Although reference is made to the weightbearing examination during this chapter, this subject, including gait analysis, is covered in greater detail in section 10B (functional assessment).

The assessment process begins with a detailed history of the patient’s complaint. Subsequent examination of the limbs is based on an approach following the methodology outlined by McRae (2004):

Qualitative, semiquantitative and quantitative measurement techniques are used. The practitioner should be aware of the likely errors that can ensue from such measurements and take these into consideration when interpreting and analysing data from the assessment (see Ch. 4).

Terms of reference

The body is divided into three cardinal planes (Fig. 10A.1):

These planes form the reference points from which are described:

Universal use of these terms of reference is important when communicating with colleagues as one can be safe in the knowledge that they will understand the nature of the pathological process being described.

Joint motion

Transverse plane

Motion in the transverse plane produces internal and external rotation of the thigh and leg and adduction and abduction of the foot.

Internal rotation occurs when the anterior surface of the distal segment rotates medially in relation to the proximal segment and external rotation when the opposite occurs – the anterior surface of the distal segment moves laterally in relation to the proximal segment (Fig. 10A.4).

In the foot, the use of the terms adduction and abduction depends upon the site of the reference point: the midline of the body or the midline of the foot. Functionally, the midline of the body is usually used as the reference point:

The mid-axial line of the forefoot is different from that of the hand. For the latter, the middle finger is taken as the mid-axial point. Muscles which abduct (dorsal interossei) and adduct (palmar interossei) the fingers take the middle finger as their reference point. Conversely in the foot the longitudinal axis has shifted pre-axially and the second toe becomes the reference point for the mid-axial line for the actions of the dorsal and plantar interossei. The adductor hallucis is inserted into the lateral side of the proximal phalanx of the hallux and is so termed because it brings about adduction of the hallux – movement of the hallux towards the midline of the foot.

Why is an orthopaedic assessment indicated?

Normal lower limb function should be free of pain and energy efficient. The main purpose of the orthopaedic assessment is to identify whether the system is functioning within the boundaries of ‘normality’. Normal function can be affected by many factors (Box 10A.1). It should be remembered that orthopaedic lower limb problems are not always isolated in origin. They may result from referred pain from a proximal source or can be part of a systemic disorder, e.g. a neuromuscular disease. It is therefore important that the lower limbs are not examined in isolation and that observation and examination of other parts of the body are undertaken where indicated.

In summary the purpose of an orthopaedic lower limb assessment is to:

The assessment process

When undertaking an assessment of the lower limb it is essential that the system is observed weightbearing (dynamic and static) and non-weightbearing. Differences between the two states can help to determine whether compensation has occurred. For example, non-weightbearing assessment may identify the presence of a forefoot varus; observation of the patient’s gait may show this problem has been fully compensated through abnormal positioning of the STJ. Conversely, information from the non-weightbearing assessment may explain the cause of a gait abnormality, e.g. a patient may have a bouncy gait due to an early heel lift; non-weightbearing assessment of the ankle joint may reveal that the cause is an ankle equinus secondary to a short gastrocnemius muscle.

To gain a full and detailed picture of the function of the locomotor system, the following factors must be assessed:

The sequence of assessment of the above varies among practitioners. There is no one correct sequence; practitioners should adopt the sequence and approach they feel most comfortable with. However, it is essential that a systematic approach is adopted to ensure vital pieces of data are not omitted. For complete assessment, the examination should involve the following three important sections:

Areas 2 and 3 are covered in greater detail in section 10B.

For successful assessment, it is important that the patient is at ease and cooperates with and has confidence in the practitioner. The practitioner should always be sensitive to the patient’s needs and explain what they are about to do and why, before undertaking the assessment. Qualitative and quantitative measurement should be undertaken where necessary, but the data must be meaningful and reproducible if they are to be of any use in assessing improvement or deterioration. Various measuring devices may be used; their use will be discussed in the appropriate sections.

General assessment guidelines

Not all the tests will be required during every lower-limb assessment. The selection of tests used will depend on the findings as the examination proceeds, and should be influenced by the preceding clinical history and observations. However, it is necessary to be thorough enough to rule out alternative pathologies. The exclusion of alternative aetiologies may require the assessment of additional systems, e.g. the cardiovascular system. Referred pain associated with local nerve entrapment or radicular patterns of pain in which spinal nerves or nerve roots are irritated need to be considered.

Remember that a problem that affects one part of the system can lead to problems elsewhere in the system. The lower limb functions as one mechanical unit and as a result a problem in one part may have to be compensated for in another part of the system. Compensation is a change in the structure, position or function of one part in an attempt to adjust to an abnormal structure, position or function in another part. For example, scoliosis of the spine may lead to an apparent leg-length discrepancy, which will affect foot function. Conversely, a problem affecting the foot, e.g. an uncompensated rearfoot varus, may lead to discomfort/pain at the knee.

The process of assessment follows a standard format:

Examination of joint movement

Features of an inflamed joint are redness (rubor), heat (calor), pain (dolor), swelling (tumour) and loss of function. Inflammation of a joint may be due to a range of factors, e.g. trauma, arthritis and infection. Examination of the joint, information from the medical and social history and results of radiological and laboratory investigations will enable a diagnosis to be made. If a patient complains of a painful joint, the characteristic features of the pain should be recorded.

Before examining a joint, it is helpful to ask the patient to move the affected limb to assess the likely range of pain-free movement. The process of joint assessment should include the following:

ROM is the amount of motion at a joint and is usually measured in degrees. The ROM at a joint can be compared with the expected ROM for that joint, e.g. if only 20° of motion occurs at the first MTPJ when the expected norm is 70° (28% of the normal ROM) it can be concluded that the ability of this joint to carry out normal function is impaired (hallux limitus). Often a guesstimate of the amount of joint motion is made from observation. Protractors, tractographs and goniometers can be used to quantify joint motion (Fig. 10A.8).

A joint may show normal ROM but the direction of the motion may be abnormal. It is, therefore, important to note the direction as well as the range. For example, the total ROM of transverse plane rotation at the hip is 90°; 45° internal rotation and 45° external rotation. If the ROM is 90° but there is 70° of external rotation and 20° of internal rotation then the ROM would be normal but the direction of the motion would be abnormal. Normal joint motion should occur without crepitus, pain or resistance (quality of motion). The ROM and direction of motion of a joint, e.g. hip, should be the same for both limbs (symmetry of motion). The presence of asymmetry of motion should always be noted.

Joint motion can be affected by the ligaments around the joint. It is important as part of joint assessment to identify any dysfunction of the ligaments, e.g. ligament tear or rupture. Finally, joints should be assessed as to whether they are subluxated or dislocated. Dislocation occurs where there is no contact between articulating surfaces of the joint and subluxation where there is only partial contact.

The range of active and passive movement of each respective lower limb joint should be examined, documented, and compared with the contralateral side. It is useful to assess whether passive movement of the joint provokes any pain or guarding (sometimes seen in hallux limitus). In addition, it is valuable to document the response to resisted testing (strong/weak/painless/painful) and stability of the joint. This will determine the integrity of the articulating surfaces and ligaments. Provoking crepitus on joint movement is an indication of joint damage.

Muscle assessment

Muscles allow active motion at joints. They should be tested for:

Non-weightbearing examination

imageThe prime purpose of the non-weightbearing examination is assessment of the joints and muscles of the lower limb and other important soft-tissue structures. A flat couch is required for the patient to lie on. Patients should feel comfortable and relaxed and should not be wearing restrictive clothing. Non-weightbearing examination involves an assessment of the following:

Examination of the hip

The hip joint is regarded as a stable ball and socket synovial joint. It has sufficient mobility to allow economic gait and stance while being more restricted than its counterpart in the upper limb, the shoulder joint (glenohumeral joint), which tolerates greater potential instability in exchange for increased motion. The hip joint’s stability is provided by:

Frontal plane movement

This should be assessed with the patient lying flat and supine, with room to assess both limbs. An exaggerated impression of available hip abduction may be gained if the pelvis is not stabilised by the examiner placing their hand on the contralateral iliac crest as the limb is moved. Then the limb is moved outwards and the arc of movement from the midline noted. If possible, when dealing with unilateral pathology, start with the normal side. Usually, enough abduction is available in the healthy hip to allow the leg to hang dependent over the couch with the knee flexed. This allows further stabilisation of the pelvis and allows comparison with the contralateral side. Normal hip abduction is at least 40°.

Adduction is best assessed after abduction. Less adduction is available than abduction – usually about 25°. It can be assessed in several different ways:

Tightness of the adductors on attempted abduction is common in osteoarthritis and other common hip pathologies. In cerebral palsy, it can lead to a scissors-type gait when one or both legs have a tendency to cross over during gait.

Transverse plane movement

Internal and external hip rotation can be assessed in several different ways. The recorded measurement might be slightly different according to the method employed. It is important that the way the assessment was conducted is recorded in the notes. Essentially there are three methods:

With the patient supine, rotation can be assessed with the hips and knees extended, i.e. the legs straight. Observe the patient from the foot of the bed and assess rotation in each limb simultaneously. Hold each heel in the palm of your hands and first externally rotate and then internally rotate each limb. In this position, rotation is derived from the hip, unless there is any knee instability. It is useful to observe the movement of the patellae as a gauge of the amount of rotation from the hip. The alternative method with the patient supine is to flex to 90° the hip and knee joints. This may be difficult if hip flexion is painful and restricted. The hip is moved both internally and externally and the angle is measured by comparing the position of the shin with respect to the midline.

With the patient prone, rotation can be assessed by flexing the knees to 90°. The legs can be simultaneously rotated outwards to assess and compare internal rotation. External rotation can be assessed with one limb extended and the other leg moved towards the midline. Alternatively, external rotation can be compared by crossing the legs. For all these manoeuvres it is important that rotation is not exaggerated by the pelvis lifting alternatively off each side.

In health, 45° of comfortable internal and external rotation is possible. In certain conditions, e.g. unilateral excessive femoral anteversion, the total rotational arc may be the same in both hips, but with a skew in one rotational direction in one hip compared to the other. Females tend to show more internal rotation than males (Svenningsen et al 1990). The range of transverse plane motion at the hip decreases with age and most hip pathologies.

Imaging of the hip joint

Aug 10, 2016 | Posted by in PHYSICAL MEDICINE & REHABILITATION | Comments Off on Musculoskeletal assessment
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