Surgical Management of Patellofemoral Instability in the Skeletally Immature Patient

Lauren H. Redler, MD; Margaret L. Wright, MD


J Am Acad Orthop Surg. 2018;26(19):e405-e415. 

In This Article

Technical Considerations

Physeal stapling and other forms of hemiepiphysiodesis have been used to correct genu valgum; however, they are not reversible and therefore must be used in older children who will reach completion of growth before overcorrection. Figure-of-8 plates act as a tension band across the physis and slow growth relative to the lateral physis without creating permanent physeal bars or tethers.[46] They can therefore be used for growth modulation techniques in younger children, allowing for faster correction. Correction of approximately 0.7° per month in the femur and 0.5° per month in the tibia can be expected, for a combined average of 1.2° per month if used together. Valgus alignment can improve an average 8° per year with a femoral hemiepiphysiodesis and an additional 4° per year with tibial hemiepiphysiodesis.[46] Faster and greater correction can be achieved when the technique is used with two plates instead of one and when it is performed on younger children.[46] Most studies advocate for overcorrection of 5° to account for the rebound phenomenon. The plates should be removed when correction is complete to avoid overcorrection, although plates may be placed on the opposite side of the physis to reverse this complication if it occurs.[1]

There are additional considerations for when MPFL reconstruction and guided growth procedures are performed together because of the proximity of the medial femoral physis to the femoral insertion of the MPFL. A femoral plate can be placed through the same incision used for the femoral fixation of the MPFL reconstruction, but should be placed before the fixation of the MPFL so that it sits directly on the periosteum. The plate is placed on the midsagittal line, with concurrent planning of the femoral MPFL fixation so that the ideal tunnel location is not blocked by the plate. During the second surgery for plate removal, the dissection should be performed carefully so that the reconstructed ligament is not disrupted.