[Biological fixation and clinical results of the cement-free Lübecker total endoprosthesis made from spongiosa metal].

We reviewed 138 primary arthroplasties performed until March 31, 1986 clinically and radiographically. They were followed up for an average of 76 months (60 to 102). 125 (90.6%) hips could be classified as very good/good, 8 (5.8%) as fair and 5 (3.6%) as poor. The average preoperative Harris hip score was 43.6 (12.61) points and the average 6-year score was 91.2 (63-100) points. Two years after implantation, thigh pain associated with the prosthesis was of minor importance (4.4%). Histological and scanning--electron microscopical examinations of the bone--metal interface of retrieved human femoral stems were done. The three-dimensional ingrowth of lamellar and woven bone accompanied by dense fibrous tissue into the "spongiosa" metal, cancellous surface of the implant was demonstrated. The clinical consequence of this mechanical "interlocking" up to a depth of 3 mm, supported by the encouraging clinical results, is evident. Cementless spongiosa metal prosthesises should be implanted in patients older than 70 years if the bone stock will be good enough.