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Surgeons revisit original cartilage repair techniques
Did surgeons miss the boat 25 years ago with this treatment? Periosteal grafts get a second look, too.
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Courtesy of Alpha Klinik |
Technological advances and a paradigm shift towards the importance of patient expectations have caused some surgeons to take a second look at conventional cartilage repair techniques.
Surgeons developed abrasion arthroplasty more than 25 years ago, but only now are they realizing the technique’s full potential. “Maybe [surgeons in the past] didn’t see enough good results and happy patients with it and so most of these people abandoned it,” Jürgen Toft, MD, CEO and chief surgeon at the Alpha Klinik in Munich, told Orthopedics Today . “It was basically laying by the wayside, if you will.”
The procedure, as initially conceived, involves abrading the exposed subchondral bone to the depth necessary to access vascularity, so that the punctuate bleeds into the defect would form a fibrin clot. Drilling or cutting into the cancellous bone was to be avoided.
Surgeons theorized that this would stimulate new cartilage. “One of the reasons why abrasion arthroplasty in the beginning didn’t really work in the hands of a lot of people was that they were abrading the bone way too deep which is enough of a stimulus for some replacement cartilage to grow, but [will also] jeopardize the weight bearing properties of the subchondral bone,” Toft said. “Then the patient was in pain afterwards, not for the loss of cartilage but for the weakened bone.”
Increased stress on the damaged structure caused osteonecrosis under the cartilage. Without the use of MRIs, surgeons discovered good arthroscopic findings but continued patient pain. Some surgeons began abrading less bone and combined the technique with osteotomy. These changes improved results. “Of course, when that happened the battle was almost lost because nobody believed in the technique anymore and most everybody had abandoned it,” Toft said. “And to this day, there is a very critical stance among the orthopedic community towards abrasion arthroplasty.”
In a study of nearly 300 patients who received abrasion arthroplasty with valgus osteotomy, Toft found that only 3% of patients had a total knee replacement 10-12 years postop. Oxford Knee Scores also revealed better outcomes for patients who underwent the operation compared to published results for total and uni procedures. “That amazed us because there are many more chances for a knee to be painful if you reconstruct it than if you replace it,” Toft said.
Investigators mailed Oxford questionnaires to 470 patients and received 296 responses. All of the patients had Grade III or IV medial compartment lesions and a minimum follow-up of 10 years, Toft said. He also performed all of the surgeries.
Patients reported a mean knee score of 38, Toft wrote in his study. While previous reports on osteotomy alone showed decreased scores over time, he found that patients who had the procedure with abrasion arthroplasty continued to improve. At 13-24 months postoperatively, patients had a mean score of 36.67 and those beyond 72 months reported a mean score of 40.86. A histological analysis also revealed hyaline-like tissue at nine years postop. “Considering the fact that various authors found no repair growth following an osteotomy alone, the additional attempt at resurfacing the bare bone appears to be worthwhile,” Toft wrote. “Furthermore, according to our own data and contrary to what has been claimed, the newly grown repair cartilage remains in place and matures to a hyaline-like tissue over time.”
Drilling brings pain?
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Just as researchers linked extensive abrasion to patient pain, some hypothesize that deeper punctures in drilling procedures also lead to patient pain. “Patients of mine who were drilled years ago awakened with more pain and it lasted,” Lanny Johnson, MD, a retired physician and professor from the College of Human Medicine in Michigan, told Orthopedics Today . He cited research by Scott F. Dye, MD, who noted that holes measuring 2-3mm in diameter or larger than 1cm remained hot on bone scans at two year postop. “Based on his clinical experience, Dr. Johnson concluded that it is the depth of the drill hole that correlates with pain; deeper drill holes result in more pain,” Myron Spector, PhD, a researcher at Brigham and Women’s Hospital, told Orthopedics Today .
Current techniques, such as microfracture, provide more shallow holes. “Microfracture has replaced drilling for most surgeons, but there are still some who, for orthopedic religious reasons, tradition or ignorance, still want to drill holes,” Johnson said. “The results are the same, pain for some time, and the surgeon probably attributes it to the original lesion.”
Patient subjectivity scores may also help surgeons re-evaluate traditional treatments such as periosteal grafts. In a randomized trial of patients receiving periosteal covers for chondral defects, researchers found that flaps injected with autologous chondrocyte implantation grew significantly more hyaline-like cartilage than those without chondrocytes (P<.03) at one-year postop. Yet, the early results showed no significant clinical differences between the groups. “The increased amount of hyaline-like cartilage did not result in better patient outcome after one year when measured with the KOOS score, so the significance of more hyaline-like cartilage in the treatment group needs to be evaluated,” said Micael Haugegaard, MD, an orthopedist at Glostrup University Hospital in Denmark.
The multicenter study included 39 patients diagnosed with Grade IV defects located on the femoral condyle. “All defects were greater than 2cm2,” Haugegaard said during his presentation at the 6th Symposium of the International Cartilage Repair Society. “During our study, we had to exclude one patient who appeared to develop rheumatoid arthritis,” he said.
The researchers randomized patients to a treatment group, which received autologous chondrocyte implanted (ACI)-covered flaps, or a control group (grafts containing a cultured serum). The groups showed similar demographics for weight, gender and age. The oldest patients in each group were 56 and 58 years old. Surgeons used a Peterson and Brittberg technique on all of the patients. “All patients, surgeons and observers were blinded [to group allocation],” Haugegaard said.
In the on-going study, investigators have collected one-year outcomes for 38 patients and 29 biopsies. “Four patients left the study prematurely, but this was after the clinical follow-up,” he said. The researchers found four cases of periosteal hypertrophy, two superficial infections and one patient with deep vein thrombosis.
Biopsies revealed increased hyaline-like cartilage in the ACI-treated group. “This study shows that the addition of autologous grown cartilage cells to a periosteal chondral defect resulted in a maturation of the reparative tissue towards hyaline cartilage,” Haugegaard said.
Despite this, the investigators discovered no differences between the cohorts on KOOS scores. “ … We didn’t do any statistics on this, but both groups improved on every question on the KOOS score,” he said. Future research will determine if these results continue at 24 and 60 months postop.
Surgeons using osteochondral allografts found steady results with the procedure over time. “The results have pretty well been consistent right from the beginning,” Allan E. Gross, MD, FRCSC, chief of orthopedic surgery at Mount Sinai Hospital told Orthopedics Today. “So the early results were enough to encourage us to continue with the program right up until the present. The volume of patients, if anything seems to be getting larger because there’s such a renewed interest in cartilage transplantation.”
Researchers have now amassed 25 years worth of data on the procedure. “Our long term results at 10 years are about 85% [survivorship],” Gross said. “At 15 years, they start to drop off between 70% to 75%.” Retrieval analysis also demonstrates chondrocyte viability. “We have evidence, in our longest biopsy, [which] is a patient that just got converted to a total knee, of cartilage viability at 25 years,” he said. Surgical indications include post-traumatic unipolar defects measuring >3 cm in diameter and 1 cm in depth.
Long-term survivorship
In an examination of 60 osteochondral allografts placed in the femoral side of the knee, Gross found a 95% graft survivorship at five years postop, 85% at 10 years and 75% survived at 15 years postoperatively. Researchers defined graft failure as graft removal alone, conversion to a total knee arthroplasty or awaiting an arthroplasty, Gross said during his presentation at the 6th Symposium of the International Cartilage Repair Society. Nine patients later received TKR and three grafts were removed. Seven patients also developed osteoarthritis after five years.
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In a second study, the researchers found similar survivorship rates using osteochondral allografts near the tibia. At five years, 95% of grafts survived vs. 71% at 15-year follow-up. Investigators examined 64 patients with a mean follow-up of 12 years. All patients had prior knee surgery.
At 12 year postop, researchers discovered that 21 patients went on to a TKR and two patients were indicated for the procedure. X-rays revealed no or mild arthritis in 61% of patients and severe arthritis in 7% of cases. “Our MRIs are showing loss of cartilage at 10 years, which is what we would expect. But still our X-rays are looking good at 12 years.”
Researchers also now know that a prior allograft does not affect the surgical difficulty of a future TKR. “What we found was that, in fact, the allograft actually restores bone stock,” Gross said. “We had some problems with total knee replacement, but the problems were much more related to the associated osteotomy — not to the graft.”
For more information:
- Gross A. Fresh osteochondral allografting. #4a-A.
- Haugegaard M, Jørgensen U, Nicolaisen T, et al. Treatment of isolated cartilage defects in the knee in patients with chronic knee pain. A double blinded prospective randomized trial with periosteal cover +/- autologous chondrocyte implantation (ACI). #2-4. Both presented at the 6th Symposium of the International Cartilage Repair Society. Jan. 8-11, 2006. San Diego.