Signs and Symptoms of Quadriceps Tendinitis
Quadriceps tendinitis presents with insidious onset of localized pain at the superior pole of the patella that is load-related, initially occurring during activity but progressing to rest pain if untreated, with well-localized tenderness on palpation that reproduces the activity-related pain. 1
Primary Clinical Presentation
Pain Characteristics
- Pain develops insidiously in relation to load, typically coinciding with increased activity or new training demands 1
- Pain quality is described as "sharp" or "stabbing" 1
- Initially occurs only during activity but can progress to pain at rest if left untreated 2
- Pain is localized to the area immediately proximal to the patella, at the insertion of the quadriceps tendon 3
Physical Examination Findings
- Well-localized tenderness on palpation that reproduces the same quality and location of pain experienced during activity 2, 1
- Swelling and asymmetry may be present in the distal anterior thigh region 1, 3
- Erythema can occur in some cases 1
- In chronic cases, muscle atrophy and limited range of motion may develop 1
Secondary Features
Functional Impairments
- Patients may experience joint stiffness and loss of joint motion 4
- Quadriceps atrophy can develop, particularly in chronic presentations 4
- Poor tolerance to loaded knee flexion activities 4
- Difficulty with activities requiring knee extension against resistance 5
Associated Findings
- Joint effusions are uncommon with tendinopathy; their presence should raise suspicion for intra-articular pathology 6
- In some cases, obliterating plica formations in the suprapatellar pouch may be present on arthroscopy 7
Acute Calcific Presentations (Rare Variant)
In rare cases, patients may present with:
- Acute on chronic knee pain with pre-existing symptoms 8
- Acute collection of calcific material within the tendon 8
- Radiographic opacities visible in the distal anterior thigh (patellar whiskers) 9
- May mimic monoarticular arthritis 9
Important Clinical Pearls
This is a degenerative condition (tendinosis), not an inflammatory process (tendinitis), characterized by collagen disorientation and fiber separation rather than acute inflammation 1. The misnomer "tendinitis" can lead to overreliance on anti-inflammatory medications that provide only short-term symptomatic relief without addressing the underlying degenerative pathology 1.