Chondromalacia Patellae

Definition

 

Patella Chondromalacia

 

Softening and fibrillation of articular cartilage of patella

 

Problem

- softening and fibrillation often seen in asymptomatic population

- can have typical anterior knee pain without retro-patellar changes

 

Epidemiology

 

Female adolescent

- recent increase in activity

 

Query on continuum to OA

May be a separate pathology

 

Aetiology

 

Unknown / varied

 

Mechanical

 

Acute

- direct trauma

- PFJ dislocation

 

Chronic

- PFJ instability / chronic maltracking

- LPPS (lat patellar pressure syndrome)

- quadriceps imbalance

- VMO weakness

 

Biological

 

Idiopathically abnormal cartilage unable to tolerate load

- inflammatory arthritis

- recurrent haemarthrosis

- sepsis

 

Iatrogenic

- repeated intra-articular steroids

- prolonged immobilisation

 

Degenerative

- primary OA

 

Pathology

 

Basal degeneration of cartilage at deep level

- pain due to nerve endings in subchondral bone being stimulated by variations in pressure

 

Classification

 

Grade 1 

- localised softening with no break in surface

 

Grade 2 

- fibrillation or fissured

 

Patella Fibrillation ArthroscopyPatella Grade 2 Chondromalaciae

 

Grade 3 

- fissuring to bone

- crab meat appearance

 

Patella Grade 3 ArthroscopyChondromalacia Patella Grade 3

 

Grade 4 

- bone exposed / full thickness chondral defect

 

Patella Grade 4 Arthroscopy

 

Symptoms

 

Anterior Knee Pain

 

Non-specific

- dull aching discomfort anterior knee

- cinema sign / sitting flexed generates pain

- stairs

- catch & pseudo-locking

- swelling

 

Signs

 

PFJ crepitus

- seen in 60% asymptomatic teens

 

Exclude malalignment

 

Xray

 

Exclude malalignment

 

Management

 

Non-operative

 

NSAIDS

Quadriceps exercises

Activity modification

Cut out brace & taping

 

Injections

- cortisone - last 2 - 6 weeks

- Hyaluronic acid - last 3 - 6 months

 

Operative

 

Options

 

Patellar Shaving

 

Federico et al Am J Sports Med 1997

- arthroscopic shaving in 36 patients with grade 2 or worse

- no malalignment

- all had some improvement

- only 50% good or excellent result

 

Unlikely to be a good option

 

Full thickness localised chondral defect

 

Subchondral Drilling / Abrasion

 

MACI

 

Gobi et al Am J Sports Med 2009

- chondral lesions on patella and trochlea

- all had reasonable symptomatic results

- tended to decline over time in patella and with multiple lesion

 

Other

 

Lateral Release

 

Indications

- chronic maltracking

 

OE

- tight lateral retinaclum

 

MRI

- tilt / lateral subluxation

- full thickness chondral lesion lateral facet

 

Fulkerson's osteotomy

 

Anteromedialisation of the tibial tubersity

 

TKR / PFJ replacement