Abstract
Background
The use of robotics in joint arthroplasty was initiated in 1992 with the introduction of the ROBODOC® Surgical Assistant device for planning and active robotic preparation of the femoral canal in THA. From 1993–1996, an FDA trial was undertaken using pin-based fiduciary markers to register the CT to the robot coordinate system. From 2000–2006, a second FDA trial was initiated using a point-to-surface matching “pinless” registration system. Combined, these two studies offer the first long-term follow-up of robot-assisted THA using an active robotic system for preparation of the femoral canal during THA.
Methods
Due to the support of an open implant architecture, patients were implanted with either the Depuy AML, Howmedica Osteoloc, or Zimmer VerSys FMT. Combining patients from the two studies, 86 THA's were performed in 63 patients using the active robotic system. Of these 63 patients, 7 were confirmed to have died and 5 have been lost to follow-up, 2 declined to participate due to infirmity, 37 are still recruiting, and 12 are currently enrolled (16 hips). Data collected included: Harris Hip Scale, HSQ-12, WOMAC, UCLA Activity Score, VAS Pain Score as well as radiographic analysis. The demographics at follow-up were:
Results
There were no revisions of the femoral component for aseptic reasons. Of the 16 hips enrolled, only two have required reoperation for head and liner change.
Clinical results are given below:
Radiographic analysis found that peri-acetabular osteolysis was present in 12.5% of hips, AP femoral osteolysis was found in 18.8% of hips, above and lateral femoral osteolysis was found in 6.3% of cases.
Conclusions
The use of active robotics for preparation of the femoral canal in THA appears safe and effective at a long-term follow-up of 14 years. The clinical results are comparable to or better than other long term studies of cementless femoral stem prostheses in terms of Harris Hip score (Aldinger et al 2003) and WOMAC Pain, Stiffness, and Physical Function score (Popischill and Knahr 2005). Patient recruitment is still ongoing.
