A TAPERED TITANIUM FEMORAL STEM INSERTED WITHOUT CEMENT IN A TOTAL HIP-ARTHROPLASTY - RADIOGRAPHIC EVALUATION AND STABILITY

The results of 416 total hip arthroplasties performed in 372 patients with insertion of a Mallory-Head titanium femoral component without ce ment were reviewed retrospectively, to determine the stability and the radiographic parameters of stability for this type of stein, The aver age duration of clinical and radiographic follow-up was 3.7 years (ran ge, 2.0 to 6.5 years), No revisions were performed to treat instabilit y of the stem, pain, or osteolysis by the time of the latest follow-up examination Although the clinical results were excellent, the radiogr aphic signs of fixation that have been well described for chromium-cob alt sterns were frequently absent, So-called endosteal spot welds, com monly seen in association, with long, extensively coated stems, were s een. infrequently, Resorptive bone-remodeling rarely extended beyond z ones 1 and 7 of Gruen et al, Both endosteal and periosteal distal cort ical hypertrophy was common, but the cause was unknown. Osteolysis of the distal aspect of the femur, shedding of the porous coating, and br eakage of the stem mere not seen, Forty-four sterns (11 per cent) had initial subsidence; however, it nearly always stabilized within six mo nths postoperatively and did not affect the eventual stability at the time of the short-term follow-up, The short-term clinical outcome conf irmed the stability of these stems that had been determined from the r adiographic findings and the lack of revisions, At the latest follow-u p examination, 323 (87 per cent) of the patients (362 [87 per cent] of the hips) had no or slight pain in the lower limb over-all and only t wenty-two (6 percent) of the patients (twenty-seven [6 per rent] of th e hips) had pain in the thigh, This tapered titanium femoral component appears to provide excellent short-term stability without resorptive bone-remodeling, osteolysis, or a high prevalence of pain in the thigh , Radiographic evaluation of stability of this stem is clearly differe nt from that of chromium-cobalt stems - particularly extensively coate d anatomic medullary locking stems - in that so-called spot welds and severe resorptive bone changes were uncommon and distal cortical hyper trophy was common.