Anatomic Reconstruction of the Patellofemoral Joint

OrthoCarolina Research Institute, Inc.

Status and phase: Completed; Phase 4

Conditions: Knee Replacement Surgery

Treatments: Procedure: Measured Resection of patellofemoral joint; Procedure: Measured resection of patella

Study type: Interventional

Funder types: Other

Identifiers

NCT01375231

10019

Details and patient eligibility

About

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).

Full description

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.

Enrollment: 52 estimated patients

Sex: All

Volunteers: No Healthy Volunteers

Inclusion criteria

1. Patients presenting for a primary total knee replacement who have failed conservative medical management.
2. Total knee replacement includes patella resurfacing.
3. Patient is willing and able to understand, sign, and date the study specific patient informed consent, to volunteer participation in the study.
4. 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

1. Patients presenting for a unicompartmental knee replacement.
2. Patients presenting for a revision total knee replacement.
3. Total knee replacement does not include patella resurfacing.
4. Patients with angular deformity greater than 15 degrees.
5. Patients with subluxation/dislocation of the patella.
6. Patients with severe patellar bone loss.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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52 participants in 2 patient groups

Measured Resection of patellofemoral joint

Active Comparator group

Description:

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

Treatment:

Procedure: Measured Resection of patellofemoral joint

Measured resection of patella

Active Comparator group

Description:

The thickness of the anterior condyle is not considered in this measurement. The goal is to restore the composite thickness of the patella only.

Treatment:

Procedure: Measured resection of patella