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.