Cell morphology, viability, osteocalcin activity, and alkaline phosphatase activity in milled versus unmilled surface of the femoral head.

PURPOSE: To evaluate cellular activity in milled versus unmilled surface of the femoral head in 21 patients who underwent robot-assisted total hip arthroplasty(THA).

METHODS

The femoral head of 21 consecutive patients who underwent robot-assisted THA for osteonecrosis was used. 10 cc of trabecular bone from the entire milled surface was obtained using a curette. The same amount of trabecular bone was obtained at least 1 cm away from the milled surface and served as a matched control. Cell morphology, viability, osteocalcin activity, and alkaline phosphatase activity in milled versus unmilled surface were assessed.

RESULTS

Cell morphology of the milled or unmilled surface was comparable; cells were smaller in the milled surface. Cell viability was a mean of 40% higher in the milled surface (107.4% vs. 67.2%, p<0.001); cell viability at 5 time points was comparable in each group. Osteocalcin activity of cells was slightly higher in the milled surface (1.43 vs. 1.24 ng/ml, p=0.69). Alkaline phosphatase activity of cells was slightly higher in the unmilled surface (150 105 vs. 141 789 U/L, p=0.078).

CONCLUSION

The milled and unmilled surfaces of the femoral head were comparable in terms of cell morphology, viability, osteocalcin activity, and alkaline phosphatase activity.