Radiographic location does not ensure precise femoral fixation site in MPFL reconstruction

Currently, it is widely accepted that the choice of an anatomic femoral fixation site is crucial for a successful medial patellofemoral ligament reconstruction. Given that it is difficult to perform reproducible medial patellofemoral ligament (MPFL) reconstructions based on palpation only, several different reproducible radiologic methods to establish an anatomic femoral tunnel have been described.

Nowadays, the most common method used to determine the anatomic femoral fixation site is the one described by Schoettle and colleagues in 2007. In a recent study, we have shown that most cases radiologic methods do not allow for an anatomic tunnel placement in MPFL reconstruction.

Therefore, we believe the final placement of the femoral attachment must be based on a thorough understanding of the relevant anatomy of this area of the knee. We must palpate the medial structures of the knee (adductor magnus tendon, adductor tubercle, medial joint line and medial epicondyle) and mark them. Then we make an incision, about 4-cm long, which extends from the adductor magnus tendon to the medial epicondyle, dissecting until we can put a hemostat under the adductor tendon and see its insertion right next to the adductor tubercle. The femoral attachment of the MPFL is distal to the apex of the adductor tubercle and parallel with the long axis of the femur. The mean linear distance between the two points is 10.6 mm.

Thus, the adductor tubercle can be used as an osseous landmark for intraoperative drilling during anatomical MPFL reconstruction.

We have concluded in our study that C-arm identification of the femoral graft placement site is only an approximation and should not be the sole basis for femoral attachment location. The only accurate way we can be sure of an anatomic femoral placement of the graft to perform an accurate execution of an MPFL reconstruction is to make a large enough incision to unequivocally identify the most important anatomic landmark, the adductor tubercle.

Reference:

Sanchis-Alfonso V, et al. Knee Surg Sports Traumatol Arthrosc. 2015; doi:10.1007/s00167-015-3523-x.

Vicente Sanchis-Alfonso, MD, PhD, is a consultant orthopedic surgeon, Hospital Nisa 9 de Octubre, Valencia, Spain. He is also member of the International Patellofemoral Study Group. He can be reached at Valle de la Ballestera # 59, 46015, Valencia, Spain; email: vicente.sanchis.alfonso@gmail.com.

Cristina Ramírez-Fuentes, MD, is a radiologist, Hospital Universitario y Politécnico La Fe, Valencia, Spain. She can be reached at Avinguda de Fernando Abril Martorell # 106, 46026, Valencia, Spain; email: crisramirezfuentes@gmail.com

Disclosures: Sanchis-Alfonso and Ramírez-Fuentes report no relevant financial disclosures.