Are short fully coated stems adequate for "simple" femoral revisions?

BACKGROUND: Many studies suggest long femoral components should be used in revision THA. However, longer stems are more difficult to insert and reduce femoral bone stock for future revisions.

QUESTIONS/PURPOSES: We investigated (1) how frequently a short (≤ 160-mm or primary-length) fully porous-coated stem could be utilized for Paprosky Type I to IIIA femoral defects, (2) how often the tip of the old stem or cement mantle was bypassed by the revision implant, (3) Harris hip scores, radiographic signs of osseointegration, and revision frequency, and (4) complications associated with these reconstructions.

METHODS: Two surgeons performed 277 femoral revisions graded as Paprosky Types I to IIIA between 2004 and 2009. When femoral canal diameter was less than 18 mm, these surgeons generally used the shortest stem capable of achieving a minimum of 4 cm of scratch fit in the femoral isthmus. Patients were evaluated clinically using the Harris hip score and radiographically for component loosening and to determine whether the revision component bypassed the prior stem tip or cement mantle.

RESULTS: A short stem was utilized in 144 of the 277 revisions (52%). In 113 (78%), the revision femoral component did not bypass the tip of the prior stem or cement mantle. The Harris hip score improved (p < 0.001) from 36 preoperatively to 76 at a mean of 4 years (range, 2-8 years). Twelve stems required repeat revision including six (4.9%) for failed ingrowth. Complications included four intraoperative fractures, three postoperative femoral fractures, one cortical perforation, and eight dislocations.

CONCLUSIONS: Primary-length extensively coated stems provided reliable fixation for ½ of our Paprosky Type I to IIIA femoral revisions. When considering the use of such a component, the revision surgeon should take into account a small risk of failed osseointegration and technical challenges associated with this technique.