Quadriceps strains and contusions

A muscular tear of one of the quadriceps bellies is a common disorder in sprinters and soccer players. An abrupt, vigorous contraction during a sprint breaks some of the muscle fibres and is felt as a sudden, painful ‘giving way’ at the front of the thigh. Alternatively, the muscular lesion may result from a direct contusion during contact sports (judo or American football), known as ‘Charley Horse’.

Patients who suffer an acute quadriceps strain will usually know right away. They are typically involved in sports requiring kicking, jumping, or initiating a sudden change in direction while running. Frequently, a sharp pain is felt, associated with a loss in function of the quadriceps. Sometimes pain will not fully develop during the athlete’s activity while the thigh is warm; consequently, the extent of the injury is underestimated. Stiffness, disability and pain then set in some time afterwards, e.g. late at night, and the following morning the patient can walk only with a limp.¹

Clinical examination shows a normal hip and knee, although passive knee flexion is painful or both painful and limited, depending on the size of the rupture. Resisted extension of the knee is painful and slightly weak. As a rule, the lesion is in the rectus femoris, usually at mid-thigh level.² The affected muscle belly is hard and tender over a large area. Sometimes a haematoma can be palpated. In serious lesions, a space can be detected by palpation. This is particularly the case in major ruptures just above the suprapatellar tendon, which occur mainly in patients over 40 years of age.³ In such cases, there is not only pain but also weakness during resisted extension, and the patient is unable to straighten the knee actively over the last 30°.

Ultrasonography is an excellent imaging modality for visualizing the quadriceps muscles; it has the ability to image the muscles dynamically and assess for bleeding and haematoma.⁴

Development of myositis ossificans as a complication of a thigh contusion is not uncommon in adolescents and young adults.⁵ It occurs in 9% of quadriceps contusions and seems to be associated with five risk factors (knee motion less than 120°, injury occurring during American football, previous quadriceps injury, delay in treatment of more than 3 days and ipsilateral knee effusion).⁶ Early diagnosis is important and is usually made with the help of sonography.^7,8 There is no proper treatment but the lesion undergoes spontaneous cure within 2 years.⁹ Therapy with deep transverse massage is contraindicated.

Adherent vastus intermedius

This condition occurs typically after a fracture of the femur. There is gross limitation of flexion, whereas the other knee movements are all full-range. Only surgical treatment can achieve an acceptable outcome.

Tendinous lesions about the patella

The quadriceps tendon has a superficial and a deep layer. The superficial layer runs without interruption from the quadriceps muscle, over the patella to the tibial tuberosity. The deep layer inserts all around the patellar border, effectively making the patella a sesamoid bone in the tendon. Tendinous lesions therefore occur not only at the inferior aspect of the bone but also at the superior, medial and lateral borders. Tendinosis about the patella is a typical overuse phenomenon in sports characterized by high demands on leg extensor speed and power, such as volleyball, basketball, soccer and athletics. It was first described by Sinding-Larsen in 1921¹¹ and Johansson in 1924.¹² Kulund¹³ and Ferretti¹⁴ also reported cases of tendinosis at the upper border of the patella. Cyriax¹⁵ describes three possible sites: the upper border (suprapatellar tendinosis), the apex – the classic ‘jumper’s knee’ (infrapatellar tendinosis) and at either side of the patella (tendinosis of the quadriceps expansion) (Fig. 54.2). The lesion was uncommon until the mid-1960s, when the syndrome of jumper’s knee became more and more frequent because of increased training and higher performance goals for athletes.^16,17 During the last few decades, these lesions have reached epidemic proportions¹⁸; in sports medicine centres, patellar tendinopathy is one of the leading reasons for consultation and often contributes to the decision to give up an athletic career.¹⁹

The history is obvious: during or after exertion, there is localized pain at the front of the knee. In mild examples, there is probably only a little pain after activity, whereas in a severe case pain forces the athlete to stop, and pain at rest can also supervene. The patient also states that walking upstairs or standing up from sitting is painful. The lesion can be classified by its symptoms into four stages (Table 54.1).13,20,21

Clinical examination reveals a normal knee with a full and painless range of movement and normal ligamentous tests. Only resisted extension is painful or uncomfortable. When the history suggests a slight quadriceps tendinitis but resisted extension is negative, the patient should take part in a training session and be re-examined immediately thereafter; this will probably reveal a minor lesion.

Palpation identifies the site. To make the deeper layers of the tendon accessible for the palpating finger, the patella must be tilted as much as possible (see pp. 716 and 717).

Conventional radiographic techniques are of no use in the diagnosis of quadriceps tendinitis. Ultrasonography, however, seems to have some value in staging the disorder.^22–24

On magnetic resonance imaging (MRI), swelling of the tendon and changes in the intrasubstance signal may be present.²⁵ However, the sensitivity and specificity of MRI is 75% and 29%, respectively. In younger patients with relatively mild symptoms, MRI does not show significant changes and in older, active patients changes may be present in asymptomatic knees.^26,27

Rupture of the quadriceps tendon

Rupture of the suprapatellar quadriceps tendon is an uncommon injury. Most of the patients are elderly, and sometimes there is diagnostic confusion with other causes of inability to use the legs, such as a mild stroke.⁴¹ The mechanism of injury usually involves forced hyperflexion or rapid extension from a weight-bearing position.⁴² Pain, swelling, a palpable gap and inability to straighten the leg against resistance are the cardinal features. Treatment is operative repair.

Lesions of the infrapatellar tendon

Tendinitis of the infrapatellar tendon (ligamentum patellae) is unusual and occurs only in rheumatic disorders. Inflammation of the peritendineum, with pain, thickening and coarse crepitus, can be found. Treatment consists of triamcinolone infiltration along the surface of the tendon.

A patellar tendon rupture may be caused by acute or chronic excessive traction force.⁴³ The tendon is then pulled from the lower pole of the patella.⁴⁴ Degenerative rheumatic disease may also give rise to rupture of the infrapatellar tendon.^45,46

Treatment is surgical.⁴⁷

Lesions of the insertion at the tibial tuberosity

Patellar fracture

Most patellar fractures are stellate fractures, occurring after a fall or a direct blow (dashboard injuries). In the last decade, an increasing number of patellar fractures in association with total knee replacement have been described.^51,52

Clinical examination shows warmth, a capsular pattern and a joint that contains blood. Resisted extension is markedly weak and painful. The combination of a gross articular pattern and marked quadriceps signs shows that the part of the quadriceps mechanism that overlies the knee joint must be at fault. Radiography confirms the diagnosis.

In young patients, an uncomplicated fracture heals quickly but early osteoarthrosis has to be expected.⁵³ When accurate reduction and stable fixation cannot be achieved, partial or total patellectomy must be considered and seems to produce satisfactory results.^54,55

Transverse fractures are uncommon, except in an elderly person with an osteoporotic patella. After the trauma, the patient can walk with pain; because the capsule enclosing the patella is not ruptured, displacement is avoided and therefore the disability is minor.⁵⁶

Introduction

Patellofemoral pain is a common condition. About 25% of the population will, at some stage in their lives, suffer from patellofemoral symptoms.⁵⁷ There is no clear consensus in the literature concerning the terminology, aetiology and treatment for pain in the anterior part of the knee. The term ‘anterior knee pain’ is suggested to encompass all pain-related problems. By excluding anterior knee pain caused by intra-articular disorders, peripatellar tendinitis or bursitis, plica syndromes, Osgood–Schlatter disease and other rarely occurring conditions, it is suggested that those remaining patients with a clinical presentation of anterior knee pain could be diagnosed as having patellofemoral pain syndrome (PFPS).⁵⁸ The term chondromalacia patellae, although once used as an all-inclusive term for anterior knee pain, is now only accepted to describe pathological lesions of the patellar articular cartilage found at arthroscopy or arthrotomy. A diagnosis of ‘chondromalacia patellae’ for anterior knee pain is made far too often.^59,60 Stougard detected cartilaginous lesions at the posterior aspect of the patella in almost every knee joint at autopsy⁶¹ and Paar and Riehl observed damage to the patellar cartilage in almost every operated knee.⁶²

The cause of patellofemoral pain is unknown.⁶³ Currently, there are two theories to explain its origin: the mechanical and the neural theory.⁶⁴

Mechanical theory

Most authors stress the importance of the congruency between the articular surfaces of the femur and the patella.^65–67 During the last decade, a great deal of emphasis was given to the idea of imbalance of the soft tissues surrounding the patella as the prime cause of patellar ‘maltracking’. The soft tissue balance is particularly critical in the first 20° of knee flexion, where the position of the patella in relation to the femur is determined by the interaction of the medial and the lateral soft tissue structures; after this 20° of motion, the patella engages the femur and the bony architecture becomes more important for the position of the patella relative to the femur.⁶⁸ Any imbalance in the soft tissue structures in the first 20° of flexion will mean that the patella does not encounter the trochlea optimally, which may lead to undue stress on various tissues around the joint and thus to pain. The imbalance may be the consequence of multiple biomechanical defaults. Weakness of the vastus medialis obliquus is thought to be the single most important factor causing momentary patellar subluxation.⁶⁹ Also, the passive stabilizing structures are usually more extensive and stronger on the lateral than on the medial side. Active stabilization is provided by the quadriceps muscle – on the lateral side the vastus lateralis and on the medial side the vastus medialis. The fibres of the vastus medialis are divided functionally into two compartments: the vastus medialis longus and the vastus medialis obliquus (VMO). The latter does not play a role in active extension of the knee but keeps the patella centred in the trochlea of the femur throughout knee extension.⁷⁰

The VMO is the only active stabilizer of the patella (Fig. 54.9); therefore the timing and the amount of activity in the VMO is critical to patellofemoral function and it is hypothesized that small changes in its activity may have considerable effects on the patellar position.⁷¹ Electromyography (EMG) studies have revealed that, in patients with patellofemoral pain, the VMO contracts at a significantly slower rate than the vastus lateralis, whereas in normal subjects the reflex response time of both muscles is equal.^72–74 A recent MRI study examined VMO size in patients with patellofemoral problems and found atrophy in all of them. Although it is not clear whether this atrophy is a result or a cause of PFPS, there is obviously a strong relationship between the two.⁷⁵

Other biomechanical factors that may contribute to the development of patellofemoral pain are tightness in the lateral structures, increased Q angle (see p. 722) and faulty foot mechanisms.76–78 In a retrospective study on 282 male and female students enrolled in physical education classes, Witvrouw et al found a significant correlation between four parameters and the development of patellofemoral pain: a shortened quadriceps muscle, an altered VMO muscle reflex response time, a decreased explosive strength and a hypermobile patella.⁷⁹

Neural theory

The normal articular cartilage is aneural, so defects in the surface are not thought to produce pain. It has therefore been suggested that irritation of the subchondral bone produces the pain.⁸⁰ Schneider et al could reproduce the typical pain sensation by raising intrapatellar pressure in about 40% of patients suffering from persistent patellofemoral pain. This subgroup was treated with a new method of intraosseous drilling and decompression. Of the patients so treated, 90% experienced pain relief more than 3 years postoperatively, which may indicate osseous hypertension as a cause of the pain.⁸¹

Some authors have sought the origin of the pain in soft tissue structures around the knee. Nociceptive nerve fibres and neural markers (S-100 protein, neurofilament protein, substance P and neural growth factor) have been demonstrated in the medial and lateral retinacula and in the infrapatellar fat pad.^82,83

From the existing studies it can be concluded that both theories are complementary rather than exclusive: the neural factor precipitates the symptoms in patients with certain biomechanical anomalies who subject their knee to overuse.

Clinical examination

It is important to stress the fact that most anterior knee pain is not caused by patellofemoral disorders but stems from infra-, supra- or peripatellar tendinitis, or a coronary ligament lesion. A basic functional examination should therefore always be performed first (see Box 54.1). However, if specific symptoms warrant, and the basic functional examination is totally negative, attention must be directed towards any peculiarities found during inspection of the patella and surrounding tissues.