No kind of surgery is a day in the park. Especially with age and/or extra weight being a factor. Knee surgery is one of the most often botched up surgeries you can ask for. I have a high school friend age 69, who has been wheel chair bound for 18 months following four failed attempts to fix his knee. First surgery got a bacterial infection embedded in the plastic knee parts and all of that had to be removed and replaced with new plastic which got infected and then they tried stainless, but during recovery at home he fell and broke his femur and destroyed the knee. Now his knee no longer bends and is not weight bearing. So they are giving him the choice of amputation or permanent lock. I have had three abdominal surgeries and one thoracic surgery in the last 18 months and three visits to the ER. As a result my upper body strength is about 30 percent of what it was before all of this started. I can no longer draw my 70# bow and it will be 2018 hunting season before my left shoulder is strong enough to do so. Rehab is slow at this age because the body heals slowly.