In a 37-year-old active male with right knee pain that worsens with squatting and deep knee flexion, what is the most likely diagnosis and recommended initial management?

Patellofemoral Pain Syndrome (PFPS)

This 37-year-old male most likely has patellofemoral pain syndrome, and should immediately begin a structured program of knee-targeted exercise therapy combined with hip strengthening exercises, supported by patient education about the benign nature of the condition. 1, 2

Clinical Diagnosis

The presentation of knee pain worsening with squatting and deep knee flexion is pathognomonic for PFPS. 2 Key diagnostic features include:

• Retropatellar or peripatellar pain that develops gradually rather than from acute trauma 1
• Pain provocation during activities requiring knee flexion under load, particularly squatting, stair climbing, and running 1, 2
• Pain during prolonged sitting with knees flexed (the "theater sign") 3
• Squatting bilaterally is the most sensitive physical examination finding for PFPS 4

PFPS accounts for 11-17% of all knee pain presentations in primary care and is caused by imbalances in forces controlling patellar tracking during knee flexion and extension. 2, 3

Initial Management Without Imaging

Imaging is not necessary before starting treatment in this patient. 3 Radiographs should only be ordered if: 3

• History of trauma or prior knee surgery exists
• Joint effusion is present
• Patient is older than 50 years (to rule out osteoarthritis)
• No improvement after 6-8 weeks of consistent conservative therapy 1, 2

Evidence-Based Treatment Protocol

Foundation: Exercise Therapy

Knee-targeted exercise therapy combined with hip strengthening must form the cornerstone of treatment. 1, 2 This approach addresses the fundamental biomechanical dysfunction:

• Knee exercises: Progressive quadriceps strengthening with emphasis on terminal knee extension 1
• Hip exercises: Hip abductor strengthening (side-lying leg raises, clamshells) and hip extensor exercises, as hip weakness is a consistent predictor of PFPS 2, 4
• Bilateral treatment: Address both limbs even though symptoms are unilateral, as bilateral muscle deficits exist regardless of symptom laterality 4
• Exercise parameters: Modify based on symptom severity and irritability 2

Critical Patient Education Component

Education must underpin all interventions to prevent the poor long-term outcomes seen in over 50% of patients who fail to persist with exercise therapy. 1, 2 Explain:

• Pain does not correlate with tissue damage and does not indicate progressive joint destruction 1, 2
• PFPS represents imbalances in patellar tracking forces, not structural damage 2
• Recovery requires consistent exercise adherence over several months 3, 5
• The condition is benign but requires active participation in rehabilitation 2

Adjunctive Interventions

Prefabricated foot orthoses should be considered if: 1, 2

• Patient responds favorably to treatment direction tests (symptom improvement during functional tasks with orthoses in place) 1, 2
• Evidence of overpronation or biomechanical dysfunction exists 2
• Most beneficial in the short term and should be customized for comfort 1

Manual therapy and taping can facilitate exercise therapy when: 1

• High symptom severity or irritability hinders rehabilitation 1
• Fear of movement is present 1
• Soft tissue mobilization of lateral retinacular structures and iliotibial band may be helpful 1

Biomechanical Assessment Details

Perform objective evaluation including: 1, 2

• Hip and knee strength assessment using hand-held dynamometry 2
• Movement pattern analysis during single leg squat 2
• Observation of knee alignment: Knee translocation forward past the toes during squatting is a major contributing factor 6
• Assessment of tissue tolerance to load 1

Common Pitfalls to Avoid

Focusing only on knee exercises without addressing hip strength is a frequent error that leads to treatment failure. 1, 4 Additional pitfalls include:

• Over-reliance on passive treatments without emphasizing active exercise therapy leads to poor long-term outcomes 2
• Inadequate patient education about the importance of exercise persistence contributes to the high rate of chronic symptoms beyond 5 years 2
• Overemphasis on imaging without adequate trial of conservative management 1
• Routine use of knee braces or NSAIDs has little supporting evidence 3

Reassessment Timeline

If no improvement after 6-8 weeks of consistent therapy, reassess the diagnosis and consider: 1, 2

• Radiographs to rule out osteoarthritis, osteophytes, or loose bodies 1, 2
• MRI if structural abnormalities such as meniscal tears, ligamentous injuries, or osteochondral lesions are suspected 2
• Referral to orthopedic surgery only after failure of comprehensive rehabilitation program 3

Activity Modification

Patients must be educated about avoiding aggravating activities during the rehabilitation phase: 5

• Reduce activities involving significant knee flexion under load (deep squatting, running, jumping) 5
• Knee flexion between 60-90 degrees creates maximal tension overload 6
• Gradual return to activities as symptoms improve, with pain guiding progression 2