San Francisco, CA (PRWEB) March 23, 2010 — Biologic Joint Reconstruction, rather than bionic (artificial) replacement, may be an appropriate first step for many people with knee joint arthritis, Kevin R. Stone, MD, chairman, the Stone Research Foundationstated at the American Academy of Orthopaedic Surgeons Annual Meeting in New Orleans, LA. These research results could have significant impact on the long-term feasibility of artificial knee replacement – the number of artificial joint replacement surgeries is predicted to increase to 3.4 million by 2030, with proportionate increases in cost.
The procedure involves combining articular cartilage repair techniques such as stem cell paste grafting with meniscus allograft replacement. Dr. Stone presented on a long-term meniscus allograft follow up study involving 115 patients (119 cases; 83 males, 32 females; average age: 46.9 years, range: 14.1 – 73.2 yrs) with severely damaged articular cartilage. Patients underwent combined meniscus allograft transplantation and articular cartilage repair and were followed for an average of 5.8 years (range: 2.1 months – 12.3 years). Patients reported their pain, activity, and function levels using validated subjective outcomes assessments before surgery and then at 2, 3, 5, 7, 10, and 12 years after surgery. Significant improvements in pain, activity, and function were found over the course of follow-up; indicating that patients improve significantly within the first 2 years after surgery and that these improvements are maintained over time.
Kaplan-Meier survival analysis calculated average procedure survival time at 9.93 years. This study is unique because severe articular cartilage damage is often considered a contraindication for meniscus allograft transplantation. However in the study procedures, arthritic cartilage was repaired often with a stem cell repair technique called paste grafting. In the repair technique, stem cells, bone and cartilage from the patients knee are removed and combined into a paste and then grafted onto the damaged area at the same time as replacement of the meniscus cartilage with a donor tissue from a cadaver.
Procedure failure was defined as progression to artificial joint replacement, or removal of the meniscus allograft without revision. Revision meniscus allograft transplantation was carried out in 8 cases (6.7%); only one of these cases ultimately failed. Twenty-five of the 119 meniscus allograft transplantations failed (20.1%) with a mean failure time of 4.65 years (range, 2.1 months – 10.37 years). The Cox proportional hazards model was used to evaluate the relationship between procedure failure and many factors. Medial versus lateral allograft, degree of joint space narrowing, malalignment, and gender had no significant effect on risk of failure.
Malalignment – being excessively knock-kneed or bowlegged – is a common contraindication for meniscus allograft transplantation. Alignment did not affect outcome in this study. “It may be that it takes more than the duration of this study for malalignment to produce negative effects on cartilage, but it also suggests that an osteotomy or angle correction of the leg may not be necessary to have good pain relief if the meniscus is replaced,” said Dr. Stone.
Increased age and increased number of previous surgeries increased the risk of failure but only slightly. Sixty six patients were younger than 50 years old at time of surgery, with an average age of 39 years. Fifty three patients were older than 50 years old at time of surgery with an average age of 56 years. Average procedure survival time for a 39 year old patient was calculated at 10.7 years; for a 56 year old patient it was calculated at 8.8 years. “Even with the effect of age, telling a 56 year old that meniscus allograft transplantation is predicted to last an average of 8.8 years is clinically significant. Most of my older patients are interested in buying time, continuing to play sports and delaying artificial joint replacement,” said Dr. Stone.
The 18 cases in the study that did progress to artificial joint replacement did so at average time of 4.8 years after meniscus allograft transplantation. Average age at time of subsequent knee arthroplasty was 60.9 years (range: 52.1 – 72.2 yrs). “With the increasing costs of primary and revision artificial joint replacement, the economic impact of delaying primary knee arthroplasty using an outpatient arthroscopic procedure for even 5 years is of interest,” said Dr. Stone.
Articular cartilage paste grafting, which combines an extensive marrow stimulating technique with stem cells, cartilage and bone grafting for articular cartilage repair was used in 56.3% of cases for treatment of severe articular cartilage damage at the time of meniscus allograft transplantation Other smaller cartilage lesions underwent a variety of more traditional cartilage repair techniques. “We speculated that addressing the damaged articular cartilage at the time of meniscus allograft transplantation allows for successful results of meniscus transplantation in patients with arthritis,” Dr. Stone said.
This long-term follow-up study, which represents the longest and largest evaluation of its kind, demonstrates that meniscus allograft transplantation in combination with articular cartilage repair provides lasting pain relief and improved function in patients with severe articular cartilage damage. All study patients presented with severe articular cartilage changes and 44.5% of the population was older than 50 at time of surgery, criteria which are commonly contraindicated for meniscus allograft transplantation. “Meniscus replacement can improve symptoms, even in severe osteoarthritis. Meniscus replacement should not be limited to young patients without articular cartilage damage,” concludes Dr. Stone. This study was also displayed in the poster sessions during the 56th Annual Meeting of the Orthopaedic Research Society, New Orleans, LA March 6 – 9, 2010.
Co-authors of the study with Dr. Stone are Ann W. Walgenbach, RNNP; Wendy Adelson, MS; Jonathan Pelsis, MHP; and Tom Turek ofThe Stone Research Foundation, San Francisco.
About The Stone Research Foundation:
The Stone Research Foundation is an independent, public, non-profit research institute based in San Francisco. Its mission is to research and develop ways to prevent, treat, and reverse arthritis and joint injuries.