Microvasculature of the cruciate ligaments and its response to injury. An experimental study in dogs

The normal vascular anatomy of the cruciate ligaments was investigated in eight dogs by microangiography, histology, and tissue-clearing (Spalteholz) techniques. The vessels were found to originate predominantly from the soft tissues (infrapatellar fat pad and synovial membrane) of the joint. The vascular response to partial surgical transection of the anteromedial mid-portion of the anterior cruciate ligament was evaluated in twelve dogs. This response, which was vigorous and extensive, appeared to arise from the soft tissues. Resection of the infrapatellar fat pad and synovial membrane at the time of injury tended to decrease this response. Spontaneous healing of the defect had not occurred in either group by eight weeks.

The predominant soft-tissue, as opposed to osseous, origin of the blood supply to the cruciate ligaments may be an important consideration in the repair of these structures. The preservation and utilization of the infrapatellar fat pad and synovial envelope may optimize the vascular response and healing of the ligament.