# Patella disorder

- Category: chronic
- Review status: reviewed (every claim checked against a document named on this page)
- Sources: ICPC-3 (WONCA International Classification of Primary Care, 3rd edition) class LD69 - condition scope only, no dose · No dose - referral pathway, no medicine given in primary care · Patellofemoral Syndrome - StatPearls - NCBI Bookshelf - https://www.ncbi.nlm.nih.gov/books/NBK557657/
- Verified date: 2026-08

## Verified against

- No dose - referral pathway, no medicine given in primary care
- Patella disorder - disease-level clinical article (patella-disorder-full.txt)

## Treatment metadata

- No drug therapy in primary care (Referral & Advice)

## Complete treatment card

```text
PATELLA DISORDER
Sources: ICPC-3 (WONCA International Classification of Primary Care, 3rd edition) class LD69 -
         condition scope only, no dose · No dose - referral pathway, no medicine given in primary
         care · Patellofemoral Syndrome - StatPearls - NCBI Bookshelf -
         https://www.ncbi.nlm.nih.gov/books/NBK557657/
Review status: REVIEWED against No dose - referral pathway, no medicine given in primary care,
               Patella disorder - disease-level clinical article (patella-disorder-
               full.txt)  (2026-08)

IS IT THIS? - reference only, to read alongside your own examination
  SYMPTOMS - what the patient reports (2)
    - A twisting knee injury with a felt pop, swelling, and a sense of the knee giving way suggests
      dislocation  [joint instability]
    - Chronic cases bring anteromedial pain, clicking, and catching that worsens with kneeling and
      deep flexion  [locking]
  SIGNS - what you find (4)
    - Acute dislocation typically produces a knee effusion or hemarthrosis, rarely seen in chronic
      cases  [hemarthrosis]
    - Tenderness is most pronounced at the medial edge of the kneecap on palpation
    - A positive J sign, the kneecap drifting laterally as the knee straightens, suggests
      instability
    - Guarding when the kneecap is pushed sideways with the knee bent 20 to 30 degrees is a positive
      apprehension sign  [guarding]
  TESTS (4)
    - AP, lateral, and sunrise knee radiographs look for fracture, loose bodies, and patella alta
    - An Insall-Salvati ratio over 1.2 signals patella alta, and under 0.8 signals patella baja
    - A CT-measured TT-TG distance above 20mm is considered abnormal and supports instability
    - MRI after a full dislocation classically shows bruising of the lateral femoral condyle and
      medial kneecap, plus MPFL tearing
  IF NOT THIS - what else fits (3)
    - ACL and MCL injuries are also considered on the differential for an acute knee injury with
      swelling
    - Meniscal injury and patellofemoral syndrome are further differentials for anterior knee pain
    - Medial synovial plica and chondromalacia are also considered for this pattern of knee pain
  Source  StatPearls "Patella Dislocation" - disease-level clinical article
  Status  traced to the source above

1. NO DRUG THERAPY IN PRIMARY CARE (REFERRAL & ADVICE)    [1st line]
   Adult    Umbrella term for kneecap disorders including recurrent patellar instability; the GP
            manages pain and refers for physiotherapy or surgical stabilisation when instability
            recurs. - Refer, with advice
   Peds     Children follow the same pathway: recognise and refer. No primary-care medicine is
            implied.
   Source   No dose - referral pathway, no medicine given in primary care
   Why      Umbrella term for kneecap disorders including recurrent patellar instability; the GP
            manages pain and refers for physiotherapy or surgical stabilisation when instability
            recurs.
   Caution  Recurrent frank dislocation, large knee effusion, locking suggesting a loose body.
            No medicine is prescribed for this in primary care - this entry is for recognition and
            referral. Anything given is decided by the service it is referred to.
            RED FLAG - First-time patellar dislocation accompanied by an osteochondral fracture or
            loose body requires prompt surgical evaluation/management.
            RED FLAG - Failure to improve with conservative management in the presence of
            predisposing anatomical factors warrants surgical referral.

Prices are indicative (dataset snapshot 2026-06); verify with the pharmacy.
```

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