Bojan Zoric, M.D.
Since the first documented arthroscopy of the hip performed in the early 1930’s, our understanding of the anatomy and function of the hip has evolved significantly. Labral pathology is one of the most common diagnoses among adolescent and young-adult patients who present for treatment of hip pain. The reported prevalence in the clinical population ranges anywhere from 22 to 55 percent. Our understanding of the biomechanical role of the acetabular labrum in the physiology of the joint has increased substantially which has led to increased efforts of labral preservation in recent years. Preserving labral function is thought to maintain a seal around the femoral head, which subsequently helps lubricate the hip joint and preserve a layer of pressurized intra-articular fluid. The labrum also creates an increased contact area between the femoral head and the acetabulum. The composite effect is that the functional labrum provides a biomechanical advantage that leads to increased hip stability, joint lubrication, load distribution and decreased contact stress. Therefore, recent studies have shown that surgical procedures that maintain and preserve functional hip anatomy, such as labral repair and FAI correction, have shown short-term superior results in terms of pain reduction, increased function and ability to return to activities than procedures where the labrum is debrided.
The concept of labral reconstruction has emerged to preserve the biomechanical advantages of a functional labrum. First described in 2009, labral reconstruction is a surgical procedure where a graft is used to reconstruct the native labrum. The indications for labral reconstruction have come to include patients where the labrum is irreparable, severely hypotrophic, ossified or segmentally deficient. Biomechanical analysis has shown improved hip contact area and restoration of intra-articular fluid pressurization, and distractive stability of the hip after labral reconstruction. Although the clinical literature is still very limited, the existing studies seem to corroborate the biomechanical data and have shown early promising results.
It should be noted that labral reconstruction is a technically demanding procedure and has a steep learning curve. This is a procedure that requires meticulous planning and preparation. The literature describes both the use of segmental and circumferential labral reconstruction grafts.
It is vital that several key steps are achieved during the procedure. First and foremost, appropriate bony work should be performed to remove any bony impingement as determined preoperatively from X-rays, MRIs and CT scans.
Adequate visualization and preparation of the acetabular rim is paramount for both placement of anchors and sizing of the graft; however, the capsule should be maintained and kept intact as much as possible to repair at the end of the case.
Careful preparation of the graft is mandatory. Multiple graft types have been reported, including the most commonly used Fascia Lata, semitendinosus auto or allograft tissue. Currently, my preference is to use Fascia Lata allograft and tubularize the graft into a 6mm tight tube. This gives the graft excellent rigidity and handling properties during the reconstruction surgery. Dr. Brian White explains that “the graft needs to be maneuvered in an aqueous environment for 30-60 minutes and cannot swell, fray or unravel. Meticulous preparation of the graft is essential. Take your time and work directly with your assistant to ensure that you have a tightly compressed, uniform in diameter (5-6 mm) and aesthetically pleasing graft that is durable. The key step is the start. Roll the graft tight to select the best section that is the most uniform in substance and diameter, and try to estimate how much will be needed to achieve the desired graft size when it is ultimately compressed with the running sutures.”
Once the graft is prepared and sized, fixation and tensioning of the graft to the acetabulum needs to be performed sequentially and through the use of multiple arthroscopic portals. The graft should approximate the normal position of the labrum so that it recreates the suction seal on the femoral head and maintains the biomechanical properties of a native labrum.
Finally, the capsule should be repaired to restore the normal stabilizing effect of the capsule.
In summary, labral reconstruction is a technically demanding procedure that is still very new and further investigation needs to be performed to identify the ideal patient population and refine the technical steps. However, the short-term results appear to be promising in a complex patient population.