- See:
TKR Menu:
- Natural History of Painful TKR:
- references:
-
Pain and Depression Influence Outcome 5 Years after Knee Replacement Surgery.
-
Impact of Psychological Distress on Pain and Function Following Knee Arthroplasty
- Potential Causes of TKR failure:
-
early failures:
- references:
-
Early failures in total knee arthroplasty.
-
Early failures among 7,174 primary total knee replacements: a follow-up study from the Norwegian Arthroplasty Register 1994-2000.
-
infected TKR
-
bone scans:
- may indicate loosening after 6-12 months, but can not distinguish between septic and aseptic loosening;
- aspiration: for gm stain & culture:
- most accurate method of dx, and is required prior to all revisions;
- remember that knee aspiration can yield false positives up to 25% of the time;
-
sed rate and
CRP
- Use of Erythrocyte Sedimentation Rate and C-Reactive Protein Level to Diagnose Infection Before Revision Total Knee Arthroplasty
-
component misplacement:
-
rotation of the femoral component:
-
rotation of tibial component:
- references:
-
Rotational malalignment of the femoral component in total knee arthroplasty.
-
Rotational malalignment of the components may cause chronic pain or early failure in total knee arthroplasty.
-
mis-sizing of components
- tibial overhang;
- over-sizing the femoral component;
-
knee arthroplasty instability:
-
patellar problems:
-
patellar frx
-
patellar clunk syndrome
-
patellar subluxation
- eccentric patellar button placement (causing patellar tilt and contact between the lateral patellar facet and the lateral femoral condyle);
- asymmetric patellar resurfacing:
- tendency to underresface the medial patellar facet;
-
component failure:
-
fibrous ingrowth:
- pain resulting from fibrous ingrowth should always be considered in a patient with a press fit femoral or tibial component;
-
polyethylene failure:
- look for asymmetrical polyethylene thickness;
- polyethylene may wear out, especially postero-medially;
- may be associated w/ osteolysis;
- polyethylene wear may yield green fluid aspirate;
-
tibial component frx:
-
patellar frx:
- Radiographs:
- comparing sunrise views and lateral films to the native knee (or ipsilateral pre-op films) can help clarify patellofemoral problems
(tracking, "stuffed" patellofemoral joint, lateral facet contact due to an undersized component, etc.)
-
component loosening:
- loosening w/ knee replacements is most often due to subsidence, in which component actually sinks into bone;
- malalignment, esp. varus alignment, usually has a causal relationship to this failure mode;
- when its unclear whether loosening or slight subsidence is present, consider obtaining radiographs under flouroscopic control;
- also consider need for subtraction arthrogram inorder to emphasize the space between bone
and cement or between cement and prosthesis;
- also indicated for sublte femoral component loosening, which is difficult to diagnose on plain radiographs;
- in study by Vyskocil et al, JBJS 1999, authors found that flourscopically assisted xrays identified significantly more radioluncent lines in femoral
components than were found by conventional xrays;
- authors note that deviation of x-ray beam of only 2.3 deg to component interface could obscure a radiolucent line of 2 mm, but despite this,
authors were unable to demonstrate a significant advantage to flouroscopically assisted radiographs to detect tibial loosening;
- references:
- Radioluncent lines and component stability in knee arthroplasty. Standard versus flouroscopically assisted radiographs.
P. Vyskocil et al. JBJS. Vol 81-B. No 1. Jan 1999. p 24.
-
Fluoroscopic evaluation of the painful total knee arthroplasty.
-
Radionuclide imaging of asymptomatic versus symptomatic total knee arthroplasties.
-
Treatment Options:
-
Role of Arthroscopy following TKR:
-
Revision TKR:
-
Physical Therapy following TKR
Mechanisms of failure of the femoral and tibial components in total knee arthroplasty.
Understanding pain in osteoarthritis
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