The use of a polyglycolide lactide cement plug restrictor in cemented femor
al fixation during total hip arthroplasty was evaluated. Femoral cement pre
ssurization was evaluated in vitro in a cadaveric model and the host respon
se to polymer degradation was evaluated in vivo in a canine total hip arthr
oplasty model. Sixteen embalmed anatomic specimen femurs were prepared for
cement femoral fixation, The intramedullary canal was plugged with either a
n ultrahigh molecular weight polyethylene cement plug restrictor or a polyg
lycolide lactide cement plug restrictor, Peak pressures in the proximal, mi
d, and distal portions of the cement mantle were recorded during cement ins
ertion, cement pressurization, and implant insertion, There was no differen
ce between the two plug groups in peak pressures throughout the cement mant
le during cement insertion, pressurization, or implant insertion. Total hip
arthroplasty using a cementless acetabular component and a cemented femora
l stem was performed in 24 dogs, The femoral intramedullary canal was plugg
ed with a polyethylene or a biodegradable cement plug restrictor. The dogs
were sacrificed at 7 weeks, 10 months, or 15 months. Radiographically, no o
steolytic lesions were seen around either plug type. Histomorphometrically,
the polyglycolide lactide plugs appeared intact at 7 weeks and partially d
egraded by 10 and 15 months. Ln both plug groups, a mild fibrohistiocytic r
eaction with infiltration of fibrocytes, histocytes, and endothelial cells
was seen. No osteolysis was observed. The results of the current study show
that femoral cement pressurization can be attained in vitro using a biodeg
radable cement plug restrictor and that for as long as 15 months in the in
vivo canine model there were no adverse reactions associated with use of th
ese plugs compared with conventional ultrahigh molecular weight polyethylen
e plugs.