Anatomic Reconstruction of the Patellofemoral Joint

Study Overview
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Brief Summary
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The investigators posit that it would be advantageous to reproduce the height of the entire patellofemoral joint in order to maintain the lever arm of the quadriceps mechanism at its preoperative level. Failure to do this may cause the quadriceps mechanism to be inefficient. For example the quadriceps mechanism would have to work harder if the total patellofemoral (PF) height is diminished. Alternatively, diminished motion or increased patellar strain may occur if the overall PF height is increased. The investigators theorize that either of these sizing errors could lead to anterior knee pain. The purpose of this study is to compare the clinical outcomes between two surgical techniques: 1) a technique of reproducing the total PF joint on both sides of the articulation (Group 1) and 2) the traditional technique of reproducing only the patellar thickness on one side of the joint (Group 2).

Detailed Description
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There is no consensus on the source of the anterior pain or the most efficacious treatment. Multiple etiologies have been theorized concerning the cause of this problem including tibiofemoral instability, patellofemoral (PF) instability, PF maltracking and patella stress fractures. It has been reported that patellofemoral forces are associated with anterior knee pain. Moreover, it has been reported that a correlation exists between the tension of the quadriceps muscle and the forces on the patella. In a biomechanical, cadaver study, Browne et al. found that a longer extensor moment arm reduced the tension on the quadriceps and reduced the patellar forces.

Official Title
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Anatomic Reconstruction of the Patellofemoral Joint: A Solution for Anterior Knee Pain

Conditions
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Knee Replacement Surgery

Intervention / Treatment
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* Procedure: Measured Resection of patellofemoral joint
* Procedure: Measured resection of patella


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients presenting for a primary total knee replacement who have failed conservative medical management. Total knee replacement includes patella resurfacing. Patient is willing and able to understand, sign, and date the study specific patient informed consent, to volunteer participation in the study. Patient is psychosocially, mentally, and physically able to comply with the requirements of the study including post-op clinical evaluations and completion of questionnaires. Exclusion Criteria: Patients presenting for a unicompartmental knee replacement. Patients presenting for a revision total knee replacement. Total knee replacement does not include patella resurfacing. Patients with angular deformity greater than 15 degrees. Patients with subluxation/dislocation of the patella. Patients with severe patellar bone loss.
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Measured Resection of patellofemoral joint<br>The goal is to remove an amount of bone from the patella so that when reconstructed, the composite thickness of the entire prosthetic patellofemoral joint is recreated | Procedure: Measured Resection of patellofemoral joint<br>* The goal is to remove an amount of bone from the patella so that when reconstructed, the composite thickness of the entire prosthetic patellofemoral joint is recreated<br>|
| Active Comparator: Measured resection of patella<br>The thickness of the anterior condyle is not considered in this measurement. The goal is to restore the composite thickness of the patella only. | Procedure: Measured resection of patella<br>* The thickness of the anterior condyle is not considered in this measurement. The goal is to restore the composite thickness of the patella only.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Anterior knee Pain | Measured by visual analog scale | 1 year postoperatively | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Knee Injury and Osteoarthritis Outcome Score (KOOS) | Measure patient reported pain, symptoms, activity of daily living, sport and recreation function and knee related quality of life | 1 year postoperative | 
| Range of Motion of knee |  | 1 year postoperative |