Non-Traumatic Anterior Knee Pain Care Pathway

8. Diagnosis

 

Diagnosis requires a thorough understanding of the patient's condition. It integrates patient stories; clinical findings; risk factor evaluations; and physical, psychological, social, and environmental aspects of pain.

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1. Patellofemoral Pain Syndrome (PFPS)

• Definition: Anterior knee pain resulting from physical and biomechanical changes.

• Prevalence: Patellofemoral pain is a common musculoskeletal condition with an estimated prevalence between 23% - 29%.

• Risk Factors: Psychosocial factors (e.g., stress, lack of social support, anxiety, depression); pain sensitization; sociodemographic factors (e.g., female sex); physical factors (e.g., low knee extensor, hip extensor, hip abductor, and hip external rotator strength); lifestyle factors (e.g., high levels of physical activity, prolonged sitting, kneeling, ascending stairs).

• Pain Location: Anterior retropatellar and/or peripatellar regions.

• Duration: Symptom onset can develop gradually or acutely. Symptoms can recur and may persist for more than 5 years in 50% of adults with patellofemoral pain.

• Signs/Symptoms: Pain in the anterior knee. Pain with lower limb loading activities (squatting, stairs, jumping).

• Physical and Neurological Examination: Pain with functional testing (squatting, stairs, jumping). Typically, there are no neurological deficits.

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Includes:

• Chondromalacia Patellae: Softening and breakdown of the cartilage on the underside of the patella, leading to pain during knee flexion activities.

• Plica Syndrome: Irritation of the synovial plica causing medial knee pain and a clicking sensation.

• Quadriceps Tendinopathy: Pain above the patella associated with jumping or running, with tenderness over the quadriceps tendon.

• Patellar Tendinopathy (Jumper's Knee)/Infrapatellar Tendinopathy: Pain at the patellar tendon (inferior pole of patella), especially with jumping or running activities, with tenderness on palpation.

• IT Band Syndrome: Pain on the lateral aspect of the knee, especially with activities such as running.

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2. Knee Bursitis (Prepatellar, Infrapatellar, Suprapatellar, Pes Anserine)

• Definition: Inflammation of a bursa at the knee.

• Prevalence: Common, particularly in individuals who engage in activities that involve prolonged kneeling or repetitive knee movements. Frequently seen in athletes, tradespeople, and older adults.

• Risk Factors: Direct trauma, repetitive actions, sustained pressure (e.g., kneeling), infection.

• Pain Location: Anterior or medial knee. Location varies based on the affected bursa.

• Duration: Acute (sudden onset) or chronic.

• Signs/Symptoms: Pain, swelling, occasionally redness.

• Physical and Neurological Examination: Point tenderness, no warmth to touch; no neurological deficits.

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3. Osgood-Schlatter Disease

• Definition: Inflammation of the patellar ligament at the tibial tuberosity.

• Prevalence: Common in adolescents, particularly those involved in sports.

• Risk Factors: Rapid growth during puberty, high levels of physical activity, overuse.

• Pain Location: Tibial tuberosity.

• Duration: Often self-limiting, symptoms can persist for months.

• Signs/Symptoms: Pain and swelling at the tibial tuberosity, often in adolescents during growth spurts; worsens with activity.

• Physical and Neurological Examination: Tenderness and swelling over the tibial tuberosity; no neurological deficits.

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4. Hoffa's Syndrome (Infrapatellar Fat Pad Impingement)

• Definition: Impingement and inflammation of the infrapatellar fat pad.

• Prevalence: Can occur in active individuals and those with repetitive knee stress.

• Risk Factors: Overuse, direct trauma to the knee, hyperextension injuries.

• Pain Location: Infrapatellar region.

• Duration: Can be chronic with intermittent exacerbations.

• Signs/Symptoms: Anterior knee pain, especially when the knee is in extension; worsens with activity.

• Physical and Neurological Examination: Tenderness around the fat pad, pain with knee extension; no neurological deficits.

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5. Osteoarthritis (OA)

• Definition: Degenerative joint disease affecting the knee.

• Prevalence: Common in older adults and those with a history of joint injury.

• Risk Factors: Older age, obesity, previous joint injury, repetitive stress on the knee joint.

• Pain Location: Affects the medial, lateral, or patellofemoral compartments of the knee.

• Duration: Chronic with intermittent exacerbations.

• Signs/Symptoms: Pain with activity, stiffness after rest, crepitus, and sometimes swelling; improves with rest.

• Physical and Neurological Examination: Joint line tenderness, bony enlargement, decreased range of motion, crepitus with movement, and possibly effusion; no neurological deficits.