In July 2010, plaintiff Dorothy Pedersen, a woman in her 80s, underwent a total right knee replacement by Dr. John Keohane, an orthopedic surgeon. After the prosthesis was placed, residual cements were noted in the knee. As a result, on Nov. 18, 2010, Keohane performed revision surgery on Pedersen to clean out the alleged cements. However, Pedersen claimed that after the second surgery, she had balance problems with her knee, requiring another revision surgery by a different surgeon. This time the whole prosthesis was replaced and a more constrained device was used instead. Pedersen sued Keohane and Keohane’s practice group, Mt. Tam Orthopedics. Pedersen alleged that the defendants failed to properly perform the first two surgeries and that their failures constituted medical malpractice. Mt. Tam Orthopedics was ultimately dismissed from the case via a motion for summary judgment. Thus, the matter continued against Keohane only. Pedersen claimed that during the first surgery, Keohane left residual cements in the knee, requiring the need for a second surgery. She also claimed that during the second surgery, Keohane negligently failed to check for appropriate ligament balancing in her right knee, requiring the need for a third surgery, which was performed by a different surgeon. The plaintiff’s expert orthopedic surgeon opined that Keohane left cements in the right knee and failed to check appropriate ligament balancing during the revision surgeries. Defense counsel argued that any alleged cement in the right knee was not caused by Keohane’s surgeries and that the cements can appear even in absence of violations of the standard of care. Counsel also argued that Keohane appropriately checked ligament balancing during the revision surgery. The defense’s expert orthopedic surgeon opined that the imaging suggested calcifications, not cements, in the knee and that these calcifications were natural. The expert also opined that Keohane would have checked for balance in the revisions, as it was part of every joint surgery, and that the failure to do so would be likened to wearing pants without buckling or zipping them up. The orthopedic surgery expert contended that checking ligament balancing would include a check of the range of motion after the prosthesis was placed, while the incision was still open, to see whether there was appropriate flexion and extension. The expert further contended that the check would include looking at the prosthesis and making sure everything was tracking and stable., Pedersen claimed that she had balance problems after her last surgery with Keohane. She subsequently underwent a second revision surgery by another surgeon on June 6, 2011, during which the whole prosthesis was replaced. Pedersen claimed that the subsequent surgery was more invasive and that she still has no improvement in her knee. Thus, she claimed that she is left with ongoing pain and instability. Defense counsel contended that Pedersen had hip problems prior to the knee surgeries and that Pedersen did not disclose this condition to Keohane. Thus, the defense’s orthopedic surgery expert opined that Pedersen’s alleged ongoing pain and instability were not from her knee surgeries, but were related to her end-stage arthritic hip.