Osteoarthritis of the knee affects millions of Americans and is painful, debilitating and interferes with the quality of life of many of our patients. Total Knee Replacement has been the gold standard treatment for end-stage disease, but the procedure can often be associated with pain, significant blood loss, medical risk, and recovery can often take months to years. Because of this, plus fear of hospitalization and a period of incapacitation, may patients elect not to undergo the procedure. Of those that do undergo total knee replacement, as many as 20 to 25% of patients end up not satisfied with their outcome. At JFK’s Orthopedic Institute we are pioneering a procedure which may offer new hope. We have been performing uni and bi-compartmental knee arthroplasty on an outpatient or overnight stay basis for over a year now. The procedures utilize Conformis Patient Specific Resurfacing implants called the i-Uni and i-Duo. Soon, JFK will be one of the first centers performing total knee resurfacing with the recent FDA approval of the iTotal device.
The knee joint has three compartments (lateral, medial, and patellofemoral). One, two or all three of these can be affected with osteoarthritis. The implants, made specifically for each patient, are constructed off of a pre-operative ct-scan. The technology, designed in conjunction with doctors from Harvard Medical School, has been FDA approved since 2007. The advantage of the procedure is that it leaves the healthy parts of the knee and only addresses the diseased part or parts. Because of this, the procedure is typically associated with less pain, minimal blood loss, shorter hospitalization, and a quicker recovery. Minimal rehabilitation is required when compared with total knee replacement. Patients typically say that it feels like their own knee, which is not typically heard of with total knee replacement.
Initial results have been promising. In the first 50 cases in 45 patients, we performed 37 medial iUni’s, 7 lateral iUni’s, 5 medial iDuo’s, and 1 lateral iDuo. Average operative time was 62 minutes. Mean drop in hemoglobin was only 1.7 gms. Mean length of stay was 1.3 days and recently 10 cases have been done on an outpatient basis. Because of the diminished pain with the procedure, we have eliminated the use of continuous femoral nerve blocks for these patients in favor of other multi-modal pain control techniques. Return to function is usually rapid with minimal physical therapy and mean flexion in the group was 125 degrees.
For those concerned about longevity of partial knee replacements, when one looks at recent follow up studies of modern partial knee designs, results are encouraging. A study in 2004 demonstrated 96% survival at 15 years of follow-up. In 2009, a study compared follow-up of partial versus total knee replacement, and found that 15 years after the procedures the partial knee group had higher survival and higher knee scores than the total knees.
We look forward to following the long term outcomes of these devices and are actively participating in a post-market clinical trial of the iUni device. In addition, we are hopeful that the iTotal will address many of the shortcomings of traditional total knee replacement and meet the expectations of higher demand patients. For more information visit www.conformis.com.
By Gregory M. Martin, M.D. Medical Director, Orthopedic Institute @ JFK