Background

There has been a recent increase in the number of reports of avascular necrosis (AVN) of the knee after arthroscopic surgery, typically occurring in patients over 50 years of age and associated with meniscectomy, chondroplasty, and the use of laser or radiofrequency.

Purpose

To report on a series of post-operative AVN in four healthy patients under the age of 30 after anterior cruciate ligament (ACL) reconstruction referred to the senior surgeon for treatment.

Study Design: Case Series, Level of Evidence: 4

Methods

This study involves 4 young healthy patients (mean age 24.5 years) who underwent ACL reconstructive surgery, all who developed significant skin changes and pain after surgery and were found to have AVN on repeat magnetic resonance imaging. A retrospective chart review was performed to identify clinical and surgical factors in all patients presented.

Results

Four otherwise healthy patients, 3 women and 1 man, developed AVN after ACL reconstruction. None had chondral damage noted at the time of their reconstruction, and 2 had meniscus tears which were repaired. The MRIs were obtained 7 – 24 months following ACL reconstruction (average 13 months). The only commonality was marked ecchymosis and blistering of the skin in the early post-operative period. The AVN affected the medial femoral condyle in two patients, the lateral femoral condyle in 1 patient, and both femoral condyles and the patella in the 4th patient.

Conclusion

Although rare, AVN should be considered if a patient has marked skin ecchymosis following ACL reconstruction, as this may be a hallmark of underlying dysvascular problems. While no one specific factor could be identified, it is important to note that all patients had abnormal skin ecchymosis about the knee at the initial post-operative visit. Thus, the surgeon should be alerted to the possibility of AVN if a patient presents post operatively with significantly more ecchymosis than one is accustomed.

What is known about the subject: Few case reports have described AVN after ACL reconstruction, with most occurring within the last 10 years.

What this study adds to existing knowledge: The young patients presented in this paper all demonstrated significant early postoperative skin changes prior to their diagnosis of AVN.