Q: Doc, I recently saw you for a torn meniscus. How long until I can drive after my surgery?
A: Here in the mountains, virtually all of us rely on driving most days. As a result, the inability to drive for a certain period of time after surgery can make life that much more difficult. Unfortunately, studies have shown that patients commonly drive while still on narcotics and while still wearing casts or splints. This fact puts other motorists, bikers, and pedestrians at significant risk.
There are no published guidelines determining a patient’s ability to drive safely. In general, law enforcement agencies determine what is impaired driving on a case by case basis. Typically, physicians feel it is safe for a patient to drive when they are no longer immobilized, they have resumed full weight bearing, and they have full grip strength. I also recommend that patients be off all narcotics during the day.
The ability to stop suddenly is critical to safe driving. Different studies have been done looking at braking quickly and effectively after surgery. In most countries, acceptable braking reaction time (which is the time it takes from when you see a stimulus to suddenly brake until your foot contacts the brake) is 750 milliseconds or less. In one study, maximum braking force was significantly reduced when a driver wore a below knee cast on the right leg and braking reaction time was also increased to unsafe levels. Wearing a below knee cast on the left leg had no effect on driving when the car had an automatic transmission and the person was not using narcotic pain pills. Having the ability to fully weight bear on the right leg is a commonly accepted criteria for fitness to drive as well as being able to walk without crutches.
In one study of patients who were treated surgically for ankle fractures, braking time was deemed safe 9 weeks after surgery or 3 weeks after the cast was removed and weight bearing started. A study looking at patients who underwent right sided hip replacement surgery found braking reaction time was actually better than before surgery at 4-6 weeks after surgery. Although it is possible to drive 1 week after left sided hip replacement surgery, you should check with your surgeon to know if the hip is safe from dislocating while sitting with the hip flexed so soon after surgery.
In another study looking at patients who underwent right knee arthroscopic meniscus surgery, the braking reaction time was decreased at 1 week from surgery but had returned to baseline at 4 weeks from surgery. In other studies looking at patients undergoing right sided knee ACL surgery and knee replacement surgery, braking reaction time was still decreased at 4-6 weeks from surgery, but returned to baseline at 8 weeks from surgery. Another similar study showed a return to normal braking reaction time in 4 weeks in these patients. As for patients undergoing left knee replacement, there was no decrease of braking reaction time.
Drivers may underestimate their ability to drive safely when immobilized after surgery. Studies have shown that driving is unsafe with any upper extremity cast in which the elbow is immobilized. In another study, drivers wearing a shoulder sling were asked to avoid certain hazards on a driving course. Although certain parameters were unaffected, drivers with a sling on were involved in significantly more crashes. Furthermore, drivers wearing a below elbow splint on the left forearm were more significantly impaired than when wearing the same splint on the right forearm.
Dr. Rick Cunningham is a Knee and Shoulder Sports Medicine Specialist with Vail-Summit Orthopaedics. He is a Physician for the US Ski Team and Chief of Surgery at Vail Valley Medical Center. Do you have a sports medicine question you’d like him to answer in this column? Visit his website at www.vailknee.com to submit your topic idea. For more information about Vail-Summit Orthopaedics, visit www.vsortho.com.