Etiology — what causes it

Load capacity mismatch at the patellofemoral joint. Contributors include hip strength deficits (gluteal weakness, hip ER weakness), quadriceps weakness, altered patellar tracking, training error, footwear changes, and sometimes anatomic factors (trochlear morphology). The classic 'maltracking' model has been broadened to a load tolerance framework.

Epidemiology — who gets it

PFPS is one of the most common knee problems in active populations, affecting up to 25% of athletes (Smith et al., PLoS One). Peak age 15–30. Female predominance roughly 2:1.

Clinical signs

Reproduction of pain with squat, step down, prolonged sitting (theater sign), and patellar grind. Hip abduction and external rotation strength deficits often present. Quad atrophy in chronic cases. No effusion, no instability, normal meniscal testing.

Symptoms

Anterior knee pain aggravated by stairs (especially descending), squatting, kneeling, running, and prolonged sitting (movie-goer sign). Often bilateral, sometimes asymmetric. Often progressive after a training spike or activity change.

Best evidence for chiropractic treatment

JOSPT 2019 CPG (Willy et al.) and the 2018 IPFRN consensus support exercise therapy as first-line — Grade A recommendation. Adding hip-focused strengthening to a knee program produces faster pain reduction and better function (Collins et al., JOSPT 2018; Lack et al., BJSM 2015). Movement re-education (cueing knee position during stair descent, single-leg squats, and running) has small-to-moderate evidence. Patellar taping and bracing have small short-term benefits as adjuncts but are not standalone solutions.

When to seek emergency care

Some symptoms need urgent medical attention — not a chiropractic visit. Call 911 or go to the nearest emergency department for: progressive limb weakness, loss of bowel or bladder control, saddle anesthesia (numbness in the groin/inner thighs), severe unrelenting pain unrelieved by position, signs of fracture after significant trauma, chest pain, stroke-like symptoms (face drooping, arm weakness, speech changes), or any rapidly worsening or unusual symptom.

Bottom line

Patellofemoral pain is a load capacity problem. Hip and quad strength are the answer — not rest, not bracing alone, and rarely surgery.