Acute Sports Injuries - FAT PAD BRUISE/CONTUSION

Fat pads consist of closely packed adipose cells surrounded by fibrous septa, which commonly divide the fat pad into separate compartments. The function of fat pads is not well established and may vary according to anatomical location. They appear to have roles in cushioning and facilitating joint lubrication. Fat pads are susceptible to acute compression injury when they are in their cushioning role, most commonly the calcaneal fat pad under the heel and the infrapatellar fat pad behind the patella tendon.

The plantar fat pad can be injured during landing onto the heel from a height, whilst the infrapatellar fat pad can be injured by landing on the knees or pinching the fat pad between the femoral condyles, proximal tibia and inferior pole of the patella during hyperextension of the knee. The infrapatellar fat pad is also often acutely injured when creating portals during knee arthroscopic surgery.

Fat pads are well vascularised and innervated. The blood supply contributes to haematoma formation (contusion) in response to acute injury, but also enables fat pad injuries to heal readily. The rich innervation of fat pads means that they can be a significant source of pain. The infrapatellar fat pad is reported to be the most pain evoking structure in the knee. The integrity and function of the calcaneal fat pad may be compromised if its organised compartments are disrupted; however, this is rare, with compression injuries sufficient to fracture the calcaneus not damaging the fibrous septa.

Management of fat pad injuries, beyond acute care techniques, includes externally padding using heel cups or knee pads and using tape to limit radial expansion of the calcaneal fat pad or unload the infrapatellar fat pad. These injuries can take a considerable time to heal.

REFERENCES Brukner, P., 2012. Brukner & Khan's clinical sports medicine. North Ryde: McGraw-Hill.