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Retropatellar contact stress in simulated patella infera
S A Meyer1, T D Brown, D R Pedersen
1Department of Orthopaedic Surgery, University of Iowa, Iowa City 52242, USA.
The American Journal of Knee Surgery
|July 1, 1997
Summary
Patella infera shifts knee contact areas but does not increase retropatellar stress. Symptoms may stem from other factors, not local mechanical overload in patellofemoral joints.
Area of Science:
- Orthopedic biomechanics
- Knee joint mechanics
- Patellofemoral joint analysis
Background:
- Patella infera, a condition of low-lying patella, may alter knee joint mechanics.
- Understanding retropatellar contact mechanics is crucial for diagnosing patellofemoral pain.
Purpose of the Study:
- To investigate the biomechanical effects of patella infera on retropatellar contact mechanics.
- To determine if patella infera leads to elevated patellofemoral contact stresses.
Main Methods:
- Utilized six cadaver knee joints tested under simulated stair descent conditions.
- Modeled varying degrees of patella infera using a distal offset mechanism.
- Quantified patellofemoral and tendofemoral contact areas and stresses via digital imaging analysis.
Main Results:
- Progressive patella infera caused proximal migration and reduced retropatellar contact areas.
- Peak and mean retropatellar contact stresses did not significantly increase.
- Quadriceps tendofemoral contact initiated earlier with increasing patella infera severity.
Conclusions:
- Patella infera alters contact area distribution but does not elevate patellofemoral contact stress.
- Disabling symptoms in patella infera may arise from non-mechanical overload factors.