Future directions

Treatment of hyaline injuries requires an aggressive approach, and still th ere will be failures.(1, 2) A clear preoperative diagnosis of the extent of articular injury is important, however, and requires the use of weightbear ing radiographs and magnetic resonance imaging. One must clearly differenti ate the difference between an isolated articular lesion (I explain it to my patients with the term "pothole") and the progression to an arthritic lesi on involving both sides of the joint. Evidence of kissing lesions, radiogra phic evidence of narrowing, or tricompartment involvement changes the diagn osis and treatment to that of early aged arthritis; these factors are contr aindications for autologous osteochondral transplant ("OATS," Arthrex, Napl es, FL), or autologous chondrocyte implantation ("ACI," Genzyme, Boston, MA ).(3, 4) The ability to produce or "grow" a new joint is in the future, and would be a tremendous step in arthritis management that conceivably could replace the metallic joint replacement. Regardless, the first future direct ion with any osteochondral injury is to treat early and aggressively before wear and tear creates an arthritic joint. Excision of an articular fragment must be weighed carefully as part of any hyaline injury treatment option.(2, 5, 6) Removal of any weightbearing surf ace dooms the patient to a poor result in over 70% at long-term follow-up o f patients with osteochondritis dissecans.(5) I am still surprised to see 1 2-year-old patients with an excised osteochondritis dissecaus (OCD) lesion facing combinations of treatment including OATS, ACI, and, sadly, osteotomy . The presence of a loose body or partially attached articular fragment sho uld be given the chance for internal fixation. The advancement of biodegrad able internal fixation devices, including screws and Fins, allows for fixat ion of fragments without metal and with ingrowth and device resorption, and may aid in healing. Obviously some fragments are too small, or are located in non weightbearing areas, and require excision. Nonetheless, the surgeon should weigh the consequences and realize that excision will create an iso lated area of fibrocartilage and eventual arthritis. Lastly, the repair of hyaline surfaces will continue to evolve and eventual ly will be decided by reproducibility, patient comfort, and cost. Comparing two commonly used procedures (OATS and ACI) is enlightening. The lesion si ze fur an OATS procedure dictates the applicability due to donor site limit ations and multiple graft edge healing limitations. ACI can be used for any size lesion, but requires two surgeries and insurance coverage (more than 16% of Americans are now without insurance, and thus are not candidates). T he cost of an OATS procedure involves only one surgery, and the cost of the cartilage harvest device. Donor site morbidity is present in both options, but is more significant in an OATS procedure. For properly indicated isola ted femoral weightbearing lesions, however both options produce a hyaline r epair that is durable and reverses the arthritic condition. What is common to both processes that must be duplicated in any future repair technique? i n my opinion as well as others, it is the chondrocyte. The presence of norm al matrix depends on a normal functioning chondrocyte. As such, cartilage-p roducing cells always will be a necessary ingredient in any hyaline repair schema. The future of successful repair minimizing donor site morbidity wil l involve the further isolation and successful creation and application of stem cell lines that recreate the hyaline surface. Until that time, however , we must treat hyaline surface injuries early, aggressively, with appropri ate indications, and use techniques that involve normal cartilage cells.