Epidemiology
1 in 10 patients with symptomatic knees have isolated PFJ OA
Aetiology
Obesity
Repetitive deep flexion
Malalignment
Lateral patella tightness
Blunt trauma
Symptoms
Anterior knee pain
- rising from chair
- ascending stairs
DDx
Plica
Tendonitis
Patella tilt
Signs
Tender patella
- especially lateral facet
Pain with movement PFJ
X-ray
Laurin View
- assess tilt
Merchant view
- assess subluxation
Lateral
Arthroscopy
Management
Non Operative
Medications
- NSAIDS
- glucosamine
Cut out braces
Exercises
- hydrotherapy
Operative
1. Lateral release
Indications
- lateral tilt
- lateral facet OA
- lateral retinacular tightness
- limited goals
Results
Aderinto et al Arthroscopy 2002
- retrospective study of 49 patients
- 80% patients felt some reduction in pain
- at 2 - 3 year follow up, 33% very satisfied and 26% satisfied
- 41% unsatisfied
2. TTT
A. Anterior transfer of TT
Maquet procedure
Elevation of TTT with insertion bone graft
- originally described elevating by 2.5 cm
- problems with skin necrosis / prominence TT / tendonitis
- reduced to only 1 cm and recommended via an anterolateral incision
Results
Largely discarded
- causes superior patella tilt
Schmid Clin Orthop Related Research 1993
- 35 knees
- 80% good, remainder fair or poor
B. Anteromedial transfer of TT
Fulkerson
Oblique osteotomy 45˚
- enables antero-medial transfer of tibial tuberosity
- unloads the PFJ and the lateral facet simultaneously
Results
Fulkerson et al Am J Sports Med 1990
- 93% good or excellent results in 30 patients at 2 years
- 75% good in 12 patients at 5 years, no excellent
3. Facetectomy
Indication
- previous fracture
- isolated OA to one facet
Options
- open
- arthroscopic
Open procedure
Midline incision
- open retinaculum medial or lateral
- excise medial or lateral facet
- leave central ridge to ensure tracking
Results
Paulos et al Arthroscopy 2008
- arthroscopic lateral release and partial lateral facetectomy
- 80% very satisfied or satisfied
4. Patellectomy
Problem
- doesn't completely relieve pain (leaves trochlea)
- extensor weakness and lag / problems with stair descent
Technique
- open retinaculum
- excise patella in full
- close retinaculum tightly
- VMO advancement
- this increases strength and decreases lag
5. PFJR
Predates TKR by 10 years
Indications
Good results in
- OA from trauma without malalignment
Poorer results in OA from unknown cause
- risk developing femoro-tibial OA
- need revision
Patient
- isolated PJF OA
- < 60 years old
Contra-indications
Inflammatory conditions
Patella maltracking and malalignment
Tibiofemoral arthritis / medial or lateral joint pain
Malalignment
Correct large Q angles preop with TTT
- some correction of maltracking can be obtained intra-op via component positioning and lateral release
Failures
PF instability
Progressive tibio-femoral degeneration
Loosening rare (< 1%)
Types
Avon (Stryker)
LCS (Depuy)
Results
Odumenya et al JBJS Br 2010
- 5 year follow up of 50 patients
- no revisions
Ackroyd et al JBJS Br 2007
- 109 patients followed up for 5 years
- survival rate 96%
- 80% good outcomes
- 28% had radiological progression of OA
Lonner et al JBJS Am 2006
- revision of 12 PFJR revised to TKR
- for progressive tibio-femoral OA or patella catching / maltracking
- good results
- all PS, no augments or stems required
Results Australian Joint Registry
7 year revision rate of 22.4%
- males and young age highest risk revision
Cause
- progression of disease 35%
- loosening 21%
- pain 11%
6. TKR