The knee and its disorders in terms of Homoeopathy

by

Dr. Rajneesh Kumar Sharma MD (Homoeopathy)

Dr. Rajneesh Kumar Sharma

MD (Homoeopathy)

Dr. (Km) Ruchi Rajput

BHMS

Homoeo Cure Research Centre P. Ltd.,

NH 74- Moradabad Road

Kashipur (UTTARANCHAL) - INDIA

Ph- 09897618594

Abstract

he knee, largest of human joints, is compound joint. Despite its single cavity in man, it is convenient to describe it as two condylar joints between the femur and tibia and a sellar joint between the patella and femur. The former are partly divided by menisci between corresponding articular surfaces. The level of the joint is at the (palpable) proximal margins of the tibial condyles. Being too complex, the knee joint is prone to have a number of disorders. To study these problems, one must be thoroughly acquainted with anatomy and normal movements of the knee joint. Then after a very keen case taking as well as physical, radiological and pathological examinations needed, the correct diagnosis, prognosis and only then the remedial diagnosis could be made to meet the cure.

Anatomy of Knee Joint

One should study the following in detail from some standard book on anatomy-

Articular Surfaces, Fibrous Capsule, Synovial Membrane, Bursae, The ligaments of the knee, Menisci, Vessels and Nerve Supply to the Joint.

The extensor mechanism of the knee

Extension of the knee is produced by the quadriceps muscle acting through the quadriceps ligament, patella, patellar ligament and tibial tubercle.

• Weakness of extension- It leads to instability, repeated joint trauma and effusion. There is often a vicious circle of pain-

→quadriceps inhibition →quadriceps wasting →knee instability →ligament stretching and further injury →pain.

• Loss of full extension- It also leads to instability, as there is failure of the screw-home mechanism. Rapid wasting of the quadriceps is seen in all painful and inflammatory conditions of the knee.

Weakness of the quadriceps is also sometimes found in lesions of the upper lumbar intervertebral discs, as a sequel to poliomyelitis, in multiple sclerosis and other neurological disorders, and in the myopathies. Quadriceps wasting may be the presenting feature of a diabetic neuropathy or secondary to femoral nerve palsy from an iliacus haematoma.

The term ‘jumper’s knee’ is used to describe a number of conditions where there is pain in the patellar ligament or its insertion: it includes the -

Sinding–Larsen–Johansson syndrome- seen in children in the 10–14 age group, where there are X-ray changes in the distal pole of the patella.

Osgood Schlatter’s disease- (often thought to be due to a partial avulsion of the tibial tuberosity) which occurs in the 10–16 age group. In it there is recurrent pain over the tibial tuberosity, which becomes tender and prominent. Radiographs may show partial detachment or fragmentation. Pain generally ceases with closure of the epiphysis. In an older age group (16–30) the patellar ligament itself may become painful and tender. This almost invariably occurs in athletes, and there may be a history of giving-way of the knee. CT scans may show changes in the patellar ligament, the centre of which becomes expanded.

 Common Pathology about the Knee

Swelling of the knee

The knee may become swollen as a result of the accumulation within the joint cavity of excess synovial fluid (Psora/Sycosis), blood (Psora/ Syphilis) or pus (Sycosis/Syphilis). Much less commonly the knee swells beyond the limits of the synovial membrane. This is seen in soft tissue injuries of the knee when haematoma (Psora/Sycosis/Syphilis) formation and oedema (Psora) may be extensive. It is also a feature of fractures, infections (Psora) and tumours (Psora/Sycosis/Syphilis) of the distal femur, where confusion may result either from the proximity of the lesion to the joint or because it involves the joint cavity directly.

Synovitis, effusion

The synovial membrane secretes the synovial fluid of the joint; excess synovial fluid (Psora/Sycosis) indicates some affection of the membrane. Joint injuries cause synovitis by tearing or stretching the synovial membrane (Syphilis). Infections act directly by eliciting an inflammatory response (Psora). The membrane itself becomes thickened (Sycosis) and its function disturbed in rheumatoid arthritis (Syphilis/Sycosis) and villo-nodular synovitis (Psora/Sycosis); both are usually accompanied by large effusions (Sycosis). In long-standing meniscus lesions and in osteoarthritis of the knee (Sycosis/Syphilis), the synovial membrane may not be directly affected, and no effusion may be present. The recognition of fluid in the joint is of great importance. Effusion indicates damage to the joint (Syphilis), and the presence of a major lesion must always be eliminated. A tense synovitis (Sycosis) may be aspirated to relieve discomfort.

Haemarthrosis

Blood in the knee is seen most commonly where there is tearing of vascular structures. The menisci are avascular, and there may be no haemarthrosis (Psora/ Syphilis/ Sycosis) when a meniscus is torn. Bleeding into the joint will take place (Psora/ Sycosis), however, if the meniscus has been detached at its periphery or if there is accompanying damage to other structures within the knee (e.g. the cruciate ligaments) (Syphilis).

Pyarthrosis

Infections of the knee joint are rather uncommon, and usually blood-borne.  Sometimes the joint is involved by direct spread from an osteitis (Psora) of the femur or tibia; rarely the joint becomes infected following surgery or penetrating wounds. In acute pyogenic infections (Psora/Syphilis), the onset is usually rapid and the knee very painful (Psora); swelling is tense (Sycosis), tenderness is widespread (Psora), and movement resisted (Syphilis). There is pyrexia and general malaise (Psora). Pyogenic infections in patients suffering from rheumatoid arthritis (Syphilis/Sycosis) have often a much slower onset, often with suppressed inflammatory changes if the patient is receiving steroids. Tuberculous infections of the knee (Psora/Syphilis) have a slow onset, spread over weeks. The knee appears small and globular, with the associated profound quadriceps wasting (Syphilis) contributing to this appearance. In gonococcal arthritis (Sycosis), great pain and tenderness (Psora) (often apparently out of proportion to the local swelling and other signs), are the striking features of this condition.  When it is thought that there is pus in a joint, aspiration should be carried out to empty it and obtain specimens for bacteriological examination. If tuberculosis is suspected, synovial biopsy to obtain specimens for culture and histology is required.

Lesions of ligaments of the knee

It is important to detect ligament injuries as they may account for appreciable disability. The commonest are-

• Recurrent effusion
• Lack of confidence in the knee
• Difficulty in undertaking strenuous or athletic activities and
• Sometimes trouble in using stairs or walking on uneven ground.

The diagnosis and interpretation of instability in the knee is difficult as the main structures round the knee have primary and secondary supportive functions, and several may be damaged.

The medial ligament has superficial and deep layers. Considerable violence is required to damage it.

• If only a few fibres are torn, no instability will be demonstrated, but stretching the ligament will cause pain.
• With greater violence, the whole of the deep part of the ligament ruptures, followed in order by the superficial part, the medial capsule, the posterior ligament, the posterior cruciate ligament and sometimes finally the anterior cruciate ligament.
• Minor tears of the medial ligament in the older patient may be followed eventually by calcification in the accompanying haematoma (Sycosis), and this may give rise to sharply localised pain at the upper attachment (Pellegrini–Stieda disease).
• The lateral ligament and capsule may be damaged by blows on the medial side of the knee which throw it into varus.
• In the case of the medial ligament, increasing violence will lead to tearing of the posterior capsular ligament and the cruciates. In addition, the common peroneal nerve may be stretched and sometimes irreversibly damaged.
• Impaired anterior cruciate ligament function is seen most frequently in association with tears of the medial meniscus. In some cases this is due to progressive stretching and attrition rupture. In others, the anterior cruciate ligament tears at the same time as the meniscus, and in the most severe injuries the medial ligament may also be affected (O’Donoghue’s triad). Isolated ruptures of the anterior cruciate ligament are uncommon, but do occur.
• Chronic laxity (Sycosis) generally results from old injuries, and may cause problems from acute, chronic or recurrent tibial subluxations. There may be a history of giving way of the knee, episodic pain (Psora), and functional impairment (Psora). There is often quadriceps wasting (Syphilis) and effusion (Sycosis) and secondary osteoarthritis (Syphilis/Sycotic) may develop.
• Posterior cruciate ligament tears are produced when in a flexed knee the tibia is forcibly pushed backwards (as for example in a car accident when the upper part of the shin strikes the dashboard). Instability (Psora/ Syphilis) is not uncommon, often leading if untreated to osteoarthritis of rapid onset.

Rotatory instability in the knee-

Tibial condylar subluxations- In this group of conditions, when the knee is stressed, the tibia may sublux forwards or backwards on the medial or lateral side, giving rise to pain and a feeling of instability in the joint (Psora/ Syphilis). The main forms are as follows:

• Anteromedial rotatory instability- The medial tibial condyle subluxes anteriorly. In the most severe cases, this follows tears of both the anterior cruciate ligament and the medial ligament and capsule. The medial meniscus may also be damaged (Syphilis) and contribute to the instability (Psora/Syphilis).
• Anterolateral rotatory instability- The lateral tibial condyle subluxes anteriorly. In the more severe cases, the anterior cruciate ligament and the lateral structures are torn, and there may be an associated lesion of the anterior horn of the lateral meniscus.
• Posterolateral rotatory instability-The lateral tibial condyle subluxes posteriorly. This may follow rupture of the lateral and posterior cruciate ligaments.
• Combinations of these lesions (particularly 1 and 2, and 2 and 3) may be found, especially where there is major ligamentous disruption of the knee.

Lesions of the menisci

• Congenital discoid meniscus- This abnormality, most frequently involving the lateral meniscus, commonly presents in childhood. It may produce a very pronounced clicking from the lateral compartment, a block to extension of the joint and other derangement signs (Syphilis).
• Meniscus tears in the young adult- The commonest cause is a sporting injury, when a twisting strain is applied to the flexed, weight-bearing leg. The trapped meniscus commonly splits longitudinally, and its free edge may displace inwards towards the centre of the joint (bucket-handle tear). This prevents full extension (with physiological locking of the joint), and if an attempt is made to straighten the knee, a painful elastic resistance is felt (Psora) (‘springy block to full extension’). In the case of the medial meniscus, prolonged loss of full extension may lead to stretching and eventual rupture of the anterior cruciate ligament (Syphilis).
• Degenerative meniscus lesions in the middle-aged- Loss of elasticity in the menisci (Syphilis) through degenerative changes associated with the ageing process may give rise to horizontal cleavage tears within the substance of the meniscus; these tears may not be associated with any remembered traumatic incident, and sharply localized tenderness in the joint line is a common feature.
• Cysts of the menisci- Ganglion-like cysts (Sycosis) occur in both menisci, but are much more common in the lateral. Medial meniscus cysts must be carefully distinguished from ganglions arising from the pes anserinus (the insertion of sartorius, gracilis and semitendinosus). In true cysts there is often a history of a blow on the side of the knee over the meniscus. They are tender (Psora), and as they restrict the mobility of the menisci (Sycosis), they render them more susceptible to tears (Syphilis).

Patellofemoral instability-

The patella has always a tendency to lateral dislocation as the tibial tuberosity lies lateral to the dynamic axis of the quadriceps. Normally, at the beginning of knee flexion, the patella engages in the groove separating the two femoral condyles (the trochlea), which helps to keep it in place as flexion continues. This system may be disturbed in a number of ways-

• There may be an abnormal lateral insertion of the quadriceps
• Tight lateral structures (Psora), or
• An increase in the angle between the axis of the quadriceps and the line of the patellar ligament (e.g. as a result of knock-knee deformity or by a broad pelvis)
• The lateral condyle may be deficient (Syphilis), or
• The patella itself may be small and poorly formed (hypoplasia) (Syphilis) or
• Highly placed (patella alta)-This is often associated with genu recurvatum. (A low set patella—known as patella baja or infera—is uncommon and may follow certain surgical corrective procedures. It is not associated with any patellar instability.)

There are a number of conditions characterized by loss of normal patellar alignment-

• Acute traumatic dislocation of the patella- This injury occurs most frequently in adolescent females during athletic activities.
• Recurrent lateral dislocation- Further painful dislocations of the patella occur, often with increasing frequency and ease.
• Congenital dislocation of the patella-. The patella may be dislocated at birth in association with other congenital abnormalities (Syphilis). The dislocation is irreducible.
• Habitual dislocation of the patella- The patella dislocates every time the knee flexes (Psora) and this is pain free (Sycosis/ Syphilis). It often arises in childhood and may be due to an abnormal attachment of the iliotibial tract, from fibrosis in a quadriceps muscle, or as a feature of one of the joint laxity syndromes (Sycosis).
• Permanent dislocation of the patella- This is uncommon and may result from an untreated childhood or adolescent dislocation.

Retropatellar pain syndromes/chondromalacia patellae

These are characterized by chronic ill-localised pain at the front of the knee, often made worse by prolonged sitting or walking on slopes or stairs (Psora). It is commonest in females in the 15–35 age groups, and the pathology is often uncertain. In a number of cases there is softening (Syphilis)) or fibrillation (Sycosis) of the articular cartilage lining the patella (chondromalacia patellae), and this may lead to patellofemoral osteoarthritis (Syphilis/Sycosis). There may be no obvious precipitating cause, but in some there is evidence of patellofemoral malalignment or other of the factors responsible for recurrent dislocation (even although there may be no history of frank dislocation).

Osteochondritis dissecans

This occurs most frequently in males in the second decade of life, and most commonly involves the medial femoral condyle. A segment of bone undergoes avascular necrosis (Psora/Syphilis), and a line of demarcation becomes established between it and the underlying healthy bone. Complete separation may occur so that a loose body is formed. The symptoms are initially of aching pain and recurring effusion (Psora), with perhaps locking of the joint if a loose body is present (Sycosis).

Fat pad injuries

The infrapatellar fat pads may become tender and swollen, and may give rise to pain on extension of the knee (Psora), especially if they are nipped between the articulating surfaces of femur and tibia. This may occur as a complication of osteoarthritis, but is seen more frequently in young women when the fat pads swell in association with premenstrual fluid retention (Psora).

Loose bodies

Loose bodies are seen most often as a sequel to osteoarthritis or osteochondritis dissecans (Sycosis/Syphilis). Much less commonly, numerous loose bodies are formed by an abnormal synovial membrane in the condition of synovial chondromatosis (Sycosis).

Osteoarthritis

The stresses of weight-bearing mainly involve the medial compartment of the knee, and it is in this area that-

• Primary osteoarthritis usually first occurs. Being overweight, the degenerative changes accompanying old age, and overwork are common factors.
• Secondary osteoarthritis may follow ligament and meniscus injuries, recurrent dislocation of the patella, osteochondritis dissecans, joint infections and other previous pathology. It is seen in association with knock-knee and bow-leg deformities, which throw additional mechanical stresses on the joint.

In osteoarthritis, the articular cartilage becomes progressively thinner, leading to joint space narrowing (Syphilis). The subarticular bone may become eburnated (Syphilis), and often small marginal osteophytes and cysts are formed (Sycosis). Exposure of bone and free nerve endings gives rise to pain and crepitus on movement. Distortion of the joint surfaces may lead to loss of movement and fixed flexion deformities (Syphilis/Sycosis).

Rheumatoid arthritis

Characteristically, the knee is warm to touch (Psora); there is effusion (Psora/Sycosis), limitation of movements (Syphilis), muscle wasting (Syphilis), synovial thickening (Sycosis),   tenderness and pain (Psora). Fixed flexion (Syphilis/Sycosis), valgus and (less commonly) varus deformities are quite common. Generally other joints are also involved, although the monoarticular form is occasionally seen.

Reiter’s syndrome

This usually presents as a chronic effusion (Sycosis) accompanied by discomfort in the joint. It is often bilateral, with an associated conjunctivitis (Psora/Sycosis/Syphilis), and there may be a history of urethritis (Psora/Sycosis/Syphilis) or colitis (Psora/Sycosis/Syphilis).

Ankylosing spondylitis

The first symptoms of ankylosing spondylitis are generally in the spine, but occasionally the condition presents at the periphery, with swelling and discomfort in the knee joint. Stiffness of the spine (Psora) and radiographic changes in the sacroiliac joints are nevertheless almost invariably present (Syphilis/Sycosis).

Disturbances of alignment

• Genu varum (bow leg) - This commonly occurs as a growth abnormality of early childhood, and usually resolves spontaneously. Rarely genu varum is caused by a growth disturbance (Psora) involving both the tibial epiphysis and proximal tibial shaft (tibia vara). In adults genu varum most frequently results from osteoarthritis, where there is narrowing of the medial joint compartment (Syphilis). It also occurs in Paget’s disease and rickets. It is less common in rheumatoid arthritis.
• Genu valgum (knock knee) - This occurs most frequently in young children where it is usually associated with flat foot. Nearly all cases resolve spontaneously by the age of 6. It is also seen in plump adolescent females and may be a contributory factor in recurrent dislocation of the patella Psora). In adults, it most frequently occurs in rheumatoid arthritis, after uncorrected depressed fractures of the lateral tibial table, and as a sequel to a number of paralytic neurological disorders (Syphilis) where there is ligament stretching and altered epiphyseal growth (Psora/Sycosis).
• Genu recurvatum- Hyperextension at the knee is seen after ruptures of the anterior cruciate ligament and in girls where the growth of the upper tibial epiphysis may be retarded from much point work in ballet classes or from the wearing of high heeled shoes in early adolescence. In the latter cases there is corresponding elevation of the patella (patella alta), contributing to a tendency to recurrent dislocation or chondromalacia patellae. More rarely, the deformity is seen in congenital joint laxity (Sycosis), poliomyelitis (Psora/Syphilis) and Charcot’s disease (Psora/Syphilis)- (amyotrophic lateral sclerosis (ALS) a disease of the motor tracts of the lateral columns and anterior horns of the spinal cord, causing progressive muscular atrophy, increased reflexes, fibrillary twitching, and spastic irritability of muscles; associated with a defect in superoxide dismutase. A number of cases are inherited as an autosomal dominant trait. This disorder affects adults, is 90–95% sporadic in nature, and is usually fatal within 2 to 4 years of onset. Variants include progressive spinal muscle atrophy, in which only a lower motor neuron component occurs, and progressive bulbar palsy, in which isolated or predominantly lower brainstem motor involvement is seen. Syn: Aran-Duchenne disease, Charcot's disease, creeping palsy, Cruveilhier's disease, Duchenne-Aran disease, Lou Gehrig's disease, muscular trophoneurosis, progressive muscular atrophy, progressive spinal amyotrophy, wasting palsy, wasting paralysis.)

Bursitis

Cystic swelling occurring in the popliteal region is usually referred to as enlargement (Sycosis) of the semimembranosus bursa. This may communicate with the knee joint, and fluctuate in size. Rupture may lead to the appearance of bruising on the dorsum of the foot, and this may help to distinguish it from deep venous thrombosis (Psora/Syphilis/Sycosis) or cellulites (Psora/Sycosis). Fluctuant bursal swellings (Psora) may also occur over the patella (prepatellar bursitis or housemaid’s knee) or the patellar ligament (infrapatellar bursitis or clergyman’s knee).

Chronic prepatellar bursitis (Sycosis), with or without local infection, is common in miners where it is referred to as ‘beat knee’; it is also associated with other occupations where prolonged kneeling is unavoidable (e.g. it is common in plumbers and carpet layers).

DIAGNOSIS OF A KNEE COMPLAINT

1. Patient’s age and sex- bearing in mind the following important distribution of the common knee conditions.

Infections are comparatively uncommon and occur in both sexes in all age groups. Reiter’s syndrome occurs in adults of both sexes; ankylosing spondylitis nearly always occurs in male adults. Ligamentous and extensor apparatus injuries are rare in children.

2. Swelling of the knee - An effusion (Psora/Sycosis/Syphilis) indicates the presence of pathology which must be investigated. (However, that the absence of effusion does not necessarily eliminate significant pathology.)

3. Mechanical problem (internal derangement) - according to the symptoms of the patient, this can be done by-

• Obtaining a convincing history of an initiating injury-
  • The degree of violence, and its direction.
  • The initial incapacity is important: for example, a footballer is unlikely to be able to finish a game with a freshly torn meniscus.
  • Whether there was bruising (not a feature of meniscal injuries) or
  • Swelling after the injury (Psora), and
  • Whether the patient was able to weight-bear.
• Asking if the knee ‘gives way’-
  • ‘Giving way’ of the knee on going down stairs or
  • Jumping from a height follows cruciate ligament tears, loss of full extension in the knee and quadriceps wasting (Syphilis).
  • ‘Giving way’ on twisting movements or walking on uneven ground follows many meniscus injuries.
• Asking if the knee ‘locks’-
  • Patients often confuse stiffness and true locking. The position of knee if it locks should be seen. Normally the knee never locks in full extension.
  •  Locking which is due to a torn meniscus generally allows the joint to be flexed fully or nearly fully, but the last 10° to 40° of extension are impossible.  Attempts to obtain full extension are accompanied by pain.
  • What produces any locking; with long-standing meniscus lesions, a slight rotational force, such as the foot catching on the edge of a carpet, may be quite sufficient.
  • In chronic lesions, weight-bearing is not an essential factor, locking not infrequently occurring during sleep.
  • If the knee is not locked at the time of the patient’s attendance, it should be asked how it became free: unlocking with a click is suggestive of a meniscus lesion.
  • Locking from a loose body may occur in various degrees of flexion.
  • There may be deformity with locking from a dislocating patella.
•  Asking about pain-
  • The circumstances in which it is present and the patient if he can localize it by pointing to the site with one finger should be identified.

Additional investigations

Occasionally a firm diagnosis cannot be made on the basis of the history and clinical examination alone. The following additional investigations are often helpful-

• Suspected internal derangement
  • Arthroscopy- may give much useful information, and in conjunction with the clinical examination will permit a firm, accurate diagnosis to be made in the majority of cases. Incorrect diagnoses are most common in lesions involving the menisci in their posterior thirds. An increasing number of conditions are amenable to arthroscopic surgery which can often be performed after diagnostic arthroscopy as a follow-on procedure during the same session.
  • MRI scans- can be useful in diagnosing lesion of the menisci and ligaments where there is uncertainty. Although an accuracy of 90% is claimed, there is often an increase in the signal intensity in the region of the posterior third of the medial meniscus which can lead to false interpretations.
  • Arthrography- may be helpful, although interpretation of the radiographs is specialized and often difficult.
  • Examination under anesthesia- If pain prevents full examination (e.g. by preventing flexion) anesthesia may allow this to be performed. This may be followed up by arthroscopy.
• Suspected acute infections
  • Aspiration and culture of the synovial fluid.
  • Blood culture.
  • Full blood count, including differential white count, and estimation of the sedimentation rate and C-reactive protein.
• Suspected tuberculosis of the knee
  • Chest radiograph.
  • Synovial biopsy, with specimens of synovial membrane being sent for both histological and bacteriological examination. At the same time, synovial fluid specimens are also sent for bacteriology and sensitivities.
  • Mantoux test.
• Suspected rheumatoid arthritis
  • Examination of other joints.
  • Estimations of rheumatoid factor.
  • Full blood count and sedimentation rate.
  • Serum uric acid.
• Further investigation of poor mineralization, bone erosions, etc-.
  • Estimation of serum calcium, phosphate and alkaline phosphatase.
  • Estimation of rheumatoid factor.
  • Serum uric acid.
  • Full blood count and differential count.
  • Skeletal survey and chest radiograph.
  • Radioisotope scan.
  • Bone biopsy.
• Further investigation of chronic effusion, aspirate negative
  • Tests as for suspected rheumatoid arthritis.
  • Brucellosis agglutination tests.
  • Radiography of the chest and sacroiliac joints.
  • Arthroscopy and synovial biopsy.
• Further investigation of severe undiagnosed pain.
• X-ray examination of the chest, pelvis and hips.
• Arthroscopy or exploration.
• Aspiration of the knee joint- Indications include the presence of a tense haemarthrosis or to obtain specimens for bacteriology in suspected infections.

ASSESSMENT

Inspection

Swelling-

a-      If there is any swelling, note if it is confined to the limits of the synovial cavity and suprapatellar pouch,

b-     Suggesting effusion, haemarthrosis, pyarthrosis or a space-occupying lesion in the joint. Note if any swelling extends beyond the limits of the joint cavity,

c-      Suggesting infection (of the joint, femur or tibia), tumour or major injury. Examine any local swelling, e.g. prepatellar bursitis (housemaid’s knee)

d-     infrapatellar bursitis (clergyman’s knee)

e-      Meniscus cyst, occurring in the joint line.

f-       Diaphyseal aclasis (exostosis, often multiple and sometimes familial).

Skin appearance-

g-      Note any bruising which suggests trauma to the superficial tissues, or knee ligaments. Bruising is not usually seen in meniscus injuries. Redness suggests inflammation.

h-      Note scars of previous injury or surgery—the relevant history must be obtained

i-        Sinus scars are indicative of previous infections, often of bone, and with the potential for reactivation

j-       Evidence of psoriasis, with the possibility of psoriatic arthritis. In beat knee.

Temperature- Note should be made for any increased local heat and its extent, suggesting in particular rheumatoid arthritis or infection. There may also be increased local heat as part of the inflammatory response to injury, and in the presence of rapidly growing tumours. Both sides must always be compared. A warm knee and cold foot suggest a popliteal artery block. Always should be checked if any warm bandage the patient may have been wearing just prior to the examination, and the peripheral pulses must be checked.

The quadriceps muscle- Slight wasting and loss of bulk are normally apparent on inspection. Examination of the contracted quadriceps by-

a-      Placing a hand behind the knee

b-     And asking the patient to press against it. The muscle tone may be felt with the free hand

c-      Now asking the patient to dorsiflex the inverted foot to show and feel the tone in the important vastus medialis portion of the muscle. Substantial wasting may be confirmed by measurement, assuming the other limb is normal. This objective test may be valuable for repeat assessments and in medico-legal cases.

d-     To begin by locating the knee joint and marking it with a ball-point pen.

e-      To make a second mark on the skin 18 cm above this.

f-       To repeat on the other leg. Compare the circumference of the legs at the marked levels. Wasting of the quadriceps occurs most frequently as the result of disuse, generally from a painful or unstable lesion of the knee, or from infection or rheumatoid arthritis.

Extensor apparatus-

A- With the patient sitting with his legs over the end of the examination couch

g-      Ask him to straighten the leg while you support the ankle with one hand.

h-      Feel for quadriceps contraction and

i-        Look for active extension of the limb.

Loss of active extension of the knee (excluding paralytic conditions) follows-

(1) Rupture of the quadriceps tendon;

(2) Many patellar fractures;

(3) Rupture of the patellar ligament;

(4) Avulsion of the tibial tubercle.

B- The site of the pathology may be determined by looking for tenderness, palpable gaps in the components of the extensor apparatus, and proximal patellar displacement.

Effusion- Small effusions are detected most easily by inspection.

a-      The first signs are bulging at the sides of the patellar ligament and obliteration of the hollows at the medial and lateral edges of the patella.

b-     With greater effusion into the knee the suprapatellar pouch becomes distended. Effusion indicates synovial irritation from trauma or inflammation.

c-      Patellar tap test- Squeeze any excess fluid out of the suprapatellar pouch with the index and thumb, slid firmly distally from a point about 15 cm above the knee to the level of the upper border of the patella.

d-     Place the tips of the thumb and three fingers of the free hand squarely on the patella, and jerk it quickly downwards. A click indicates the presence of effusion. N.B. If the effusion is slight or tense, the tap test will be negative.

e-      Fluid displacement test- Small effusions may be detected by this manoeuvre.  Evacuate the suprapatellar pouch as in the patellar tap test.

f-       Stroke the medial side of the joint to displace any excess fluid in the main joint cavity to the lateral side of the joint.

g-      Now stroke the lateral side of the joint

h-      While closely watching the medial. Any excess fluid present will be seen to move across the joint and distend the medial side. This test will be negative if the effusion is gross and tense. In a haemarthrosis, the joint has a doughy feel in the suprapatellar region, while in a pyarthrosis there is widespread tenderness.

Tenderness

It is the first essential to identify the joint line quite clearly.

a-      Begin by flexing the knee and looking for the hollows at the sides of the patellar ligament; these lie over the joint line. Then confirm by feeling with the fingers or thumb for the soft hollow of the joint with the firm prominences of the femur above and the tibia below.

b-     Begin by palpating carefully from in front and then back along the joint line on each side. Localised tenderness here is commonest in meniscus, collateral ligament and fat pad injuries.

c-      Now systematically examine the upper and lower attachments of the collateral ligaments. Associated bruising and oedema is a feature of acute injuries.

d-     In children and adolescents, tenderness is found over the tibial tubercle (which may be prominent) in Osgood–Schlatter’s disease and after acute avulsion injuries of the patellar ligament and its tibial attachment.

e-      Tenderness over the lower pole of the patella is found in Sinding–Larsen–Johansson disease.

f-       Where a problem with the patellar ligament is suspected in an athletic patient, look for patellar ligament tenderness, especially while the patient is attempting to extend the leg against resistance. In suspected osteochondritis dissecans

g-      flex the knee fully and look for tenderness over the femoral condyles). Note that osteochondritis dissecans most frequently involves the medial femoral condyle.

Movements

Extension (normal = 0°) - Normally the line of the tibia and femur should coincide, with full extension being recorded as 0°. Loss of full extension may he described as ‘the knee lacks X° of extension’.

a-      Try to obtain full extension if this is not obviously present. A springy block to full extension is very suggestive of a bucket handle meniscus tear. A rigid block (commonly described as a fixed flexion deformity) is often present in the arthritic knee.

b-     Hyperextension (genu recurvatum) - is present if the knee extends beyond the point when the tibia and femur are in line, and is recorded as ‘X° hyperextension’. It is often seen in girls associated with a high patella, chondromalacia patellae and recurrent dislocation of the patella. It sometimes accompanies tears of the anterior cruciate, medial ligament, or medial meniscus. If severe, look for other signs of joint laxity.

Flexion (normal = 135° or more) –

c-      Measure the range of flexion using a goniometer. Flexion of 135° and over is regarded as normal, but compare the two sides. Loss of flexion is common after local trauma, effusion and arthritic conditions.

d-     Alternatively, measure the heel to buttock distance with the leg fully flexed. (This can be a very accurate way of detecting small alterations in the range, with 1 cm = 1.5° approximately, and is useful for checking daily or weekly progress.)

The range of movements in the examples would be recorded as follows:

(A) 0–135° (normal range);

(B) 5° hyperextension–140° flexion; (C) 10–60° (or 10° fixed flexion deformity with a further 50° flexion).

Genu valgum and varus

a-      In children, it should be noted if any genu valgum (knock- knee) is unilateral or bilateral. a- Assess by bringing the legs together, to touch lightly at the knees. Normally the knees and malleoli should touch. Make sure the patellae are pointing upwards. Measure the intermalleolar gap. In the older 10–16 age group, < 8 cm in females and < 4 cm in males is regarded as normal.

b-     Genu varum (bow leg) may be assessed by measuring the distance between the knees, using the fingers as a gauge. The patient should be weight-bearing, and the patellae should be facing forwards. In the 10–16 age groups, < 4 cm in females and < 5 cm in males is regarded as being within normal limits.

Radiographs may help. In (A) rickets, note the wide and irregular epiphyseal plates. In (B) tibia vara, notable is the sharply down-turned medial metaphyseal border. Note that radiological varus is normal till a child is 18 months old.

In adults, genu valgum deformity is seen most often in association with rheumatoid arthritis. It is also common in teenage girls. It is best measured by X-ray, and the films should be taken with the patient taking all his weight on the affected side (C) (and preferably in 30° flexion). The degree of valgus (vl) may be roughly assessed by measuring the angle formed by the tibial and femoral shafts and deducting the ‘normal’ tibiofemoral angle (tf), which is approximately 6° in the adult. The shaded area represents genu valgum. (Note that the tibiofemoral angle is virtually the same as the Q-angle used in the assessment of patellar instability.) Genu varum (D) may be assessed by adding the ‘normal’ tibiofemoral to the actual (negative) angle (na). It is seen most commonly in osteoarthritis and Paget’s disease etc.

Knee instability

The following potential deformities may be looked for:

(A) Valgus- (when the medial ligament is torn: severe when the posterior cruciate is also damaged);

(B) Varus- (when the lateral ligament is torn: severe when the posterior cruciate is also torn);

(C) Anterior displacement of the tibia (anterior cruciate tears: worse if medial and/or lateral structures torn);

(D) Posterior displacement of the tibia (posterior cruciate ligament tears).

Rotatory-

(1) The medial tibial condyle subluxes anteriorly (anteromedial instability): this is usually due to combined tears of the anterior cruciate and medial structures;

(2) The lateral condyle subluxes anteriorly (anterolateral instability): this is usually due to tears of the anterior cruciate plus the lateral structures;

(3) The lateral tibial condyle subluxes posteriorly (posterolateral instability) or

(4) The medial tibial condyle subluxes posteriorly (posteromedial instability);

(5)  Combinations of these instabilities.

Types (3) and (4) are mainly due to tears of the posterior cruciate and lateral or medial structures.

Examining for valgus stress instability- Begin by examining the medial side of the joint, and the medial ligament in particular. Tenderness in injuries of the medial ligament is commonest at the upper (femoral) attachment and in the medial joint line. Bruising may be present after recent trauma, but haemarthrosis may be absent. Extend the knee fully.

a-      Use one hand as a fulcrum, and

b-     with the other attempt to abduct the leg. Look for the joint opening up, and the leg going into valgus.

c-      Moderate valgus is suggestive of a major medial and posterior ligament rupture.

d-     Severe valgus may indicate additional cruciate (particularly posterior cruciate) rupture. If in doubt, the thumb or index, placed over the joint line may be used to detect any opening up as it is stressed. If there is still some uncertainty, compare the two sides.

a-      If no instability has been demonstrated with the knee fully extended, repeat the tests with the knee flexed to 30° and

b-     the foot internally rotated. Some opening up of the joint is normal, and it is essential to compare sides.

c-      Demonstration of an abnormal amount of valgus suggests less extensive involvement of the medial structures (e.g. partial medial ligament tear.

d-     If the knee is very tender and will not permit the pressure of a hand as a fulcrum, attempt to stress the ligament with a cross-over arm grip, with one hand placed over the proximal part of the tibia distal to the knee joint.

e-      Stress films. If there is still some doubt, then compare radiographs of both knees, taken while applying a valgus stress to each. (In (e) there is evidence of opening up of the join, suggestive of a medial ligament tear when compared with the other side.) If a haemarthrosis is present (and this is not always the case), preliminary aspiration of the joint may allow a more meaningful examination of the joint.

Examination under anesthesia- If the knee remains too painful to permit examination, the joint should be fully tested under anesthesia; there should be provision to carry on with a surgical repair or with an arthroscopy should major instability be demonstrated (i.e. where there is the involvement of several major structures).

Examining for varus stress instability- First examine the lateral side of the joint, looking for tenderness over the lateral ligament and capsule: then attempt to produce a varus deformity by placing one hand on the medial side of the joint and forcing the ankle medially. Carry out the test as in the case of valgus stress instability, first in full extension and then in 30° flexion, and compare one side with the other. Varus instability in extension as well as flexion, suggests tearing of the posterior cruciate ligament as well as the lateral ligament complex. Check the common peroneal nerve. Stress films and examination under anesthesia may be required.

Anterior instability

A-     The anterior drawer test- Flex the knee to 90°, with the foot pointing straight forwards, and steady it by sitting on or close to it. Grasp the leg firmly with the thumbs on the tibial tubercle.

B-     Check that the hamstrings are relaxed, and jerk the leg towards you. Repeat with the knee flexed to 70°, and compare the sides. Note that significant displacement (i.e. the affected side more than the other) confirms anterior instability of the knee. When the displacement is marked (say 1.5 cm or more), the anterior cruciate is almost certainly torn (s), and there is a strong possibility of associated damage to the medial complex (medial ligament and medial capsule) and even the lateral complex. If the displacement is less marked, and one tibial condyle moves further forward than the other, the diagnosis is less clear: it may suggest an isolated anterior cruciate ligament laxity or a tibial condylar subluxation (rotatory instability).

C-    Repeat the test with the foot in 15° of external rotation. Excess excursion of the medial tibial condyle suggests a degree of anteromedial (rotatory) instability, with possible involvement of the medial ligament as well as the anterior cruciate ligament.

D-    Now turn the foot into 30° of internal rotation, and repeat the test. Anterior subluxation of the lateral tibial condyle suggests some anterolateral rotational instability, with possibly damage to the posterior cruciate and the posterior ligament as well as the anterior cruciate ligament. Beware of the following fallacy: a tibia already displaced backwards as a result of a posterior cruciate ligament tear may give a false positive (fp) in the drawer tests. This also applies to the following Lachman tests. Check by inspection of the contours of the knee prior to the examination.

E-     The Lachman tests- These are also used to detect anterior tibial instability. In the manipulative Lachman test, the knee should be relaxed and in about 15° flexion. One hand stabilizes the femur while the other tries to lift the tibia forwards. The test is positive if there is anterior tibial movement (detected with the thumb in the joint (t)), with a spongy end point. Feagin and Cooke recommend that the test be performed with the patient prone with the thigh supported with a sandbag (G).

F-     In the active Lachman test- the relaxed knee is supported at 30° and the patient asked to extend it. If the test is positive, there will be anterior subluxation of the lateral tibial plateau as the quadriceps contracts, and posterior subluxation when the muscle relaxes. It is considered that this is best seen from the medial side. Repeat, resisting extension by applying pressure to the ankle.

G-    Radiological analysis of anterior cruciate function- The lower thigh is supported by a sandbag, and the leg extended against the resistance of a 7 kilo weight. The limb should be in the neutral position, with the patella pointing upwards, and the X-ray film cassette placed between the legs. On the films, draw two lines parallel to the posterior shaft of the tibia, with one tangent to the medial tibial plateau and the other tangent to the medial femoral condyle. Measure the distance between them.

Normal = 3.5 mm ± 2 mm.

Ruptured anterior cruciate = 10.2 mm ± 2.7 mm.

The latter figure is slightly increased if the medial meniscus is also torn. The diagnostic reliability of this examination is high.

Posterior instability

a-      Testing the posterior cruciate ligament- Rupture, detachment or stretching of the posterior cruciate ligament may permit the tibia to sublux backwards, often with a diagnostic deformity. (The knee should be flexed 20°, with a sandbag under the thigh.)

b-      Ask the patient to lift the heel from the couch, while observing the knee from the side. Any posterior subluxation should normally correct.

c-      Now place the thumb on one side of the joint line and the index on the other to assess any tibial movement.

d-      Try to pull the tibia forwards with the other hand. If the posterior cruciate ligament is torn, and the tibia subluxed posteriorly, the forward movement as the tibia reduces will be easily felt.

e-      If the posterior cruciate is lax or torn, but subluxation has not yet occurred (uncommon), then backward pressure on the tibia will normally produce a detectable, excessive posterior excursion of the tibia (posterior drawer test). 

Radiological examination of posterior cruciate ligament function- A sandbag is placed behind the thigh, and the proximal tibia forcibly pressed backwards (with a force equivalent to 25 kilos). This is repeated, and after the second preloading cycle, radiographs are taken while the same force is maintained. The gap between the medial femoral and tibial condyles (m) is measured, along with that between the lateral condyles (l). A displacement in the order of 8 mm on each side is indicative of an uncomplicated posterior cruciate tear. Excessive movement on the lateral or medial sides indicates posterolateral or posteromedial instability. Note that MRI scans allow an accurate assessment of the state of the cruciate ligaments in 80% of cases, although this is inferior to clinical assessment. The cruciates may also be inspected by arthroscopy.

Rotatory instability-

a-      Begin by looking for bruising, tenderness

b-      or oedema over the collateral ligaments. Perform the drawer tests, noting any variations.

c-      Test for laxity on valgus stress (often positive in anterior subluxations of the medial tibial condyle), and on varus stress (usually positive when the lateral tibial condyle subluxes forwards or backwards).