Histomorphochemical comparison of microfracture as a first-line and a salvage procedure: is microfracture still a viable option for knee cartilage repair in a salvage situation?

Abstract

Microfracture is considered as the first-line procedure for knee cartilage

repair, but the results of microfracture seem less predictable and rather

controversial in a salvage situation. Thus, the purpose of the study was to

histomorphochemically compare microfracture as a salvage procedure with

microfracture as a first-line procedure in a rabbit model. We hypothesized that

microfracture in a salvage situation would result in histomorphochemically

inferior cartilage repair compared to microfracture as a first-line procedure,

and the inferiority would be attributed to less migration of reparable marrow

cells to the defect due to destruction of microarchitecture of the subchondral

bone. Thirty-six New Zealand white rabbits were divided into three groups: (i)

untreated full-thickness chondral defect, (ii) single microfracture treatment

(first microfracture group), and (iii) repeated microfracture in 8 weeks after

the first procedure (second microfracture group). In each group, rabbits were

sacrificed at the end of 8 weeks, and osteochondral specimens at the repair sites

were obtained for histomorphochemical analysis. Results showed that microfracture

as a salvage procedure resulted in overall inferior cartilage repair

histomorphochemically compared with microfracture as a first-line procedure,

which correlated with deteriorative changes in the quality of underlying

subchondral bone rather than intrinsic incapability to recruit the reparative

cells in the defect area. In conclusion, although a comparable number of

reparable cells and a mechanically weakened subchondral bone are anticipated,

more study is necessary to clearly determine when a microfracture should be

performed in a situation.