Aim

Bumps and lumps of the hand are a common cause for consultation in general practice. However not all of these lesions are of true neoplastic nature and malignant tumours are a rarity in this location.

Intruduction: Cementless cup anchorage for total hip replacement is among the techniques widely accepted today. Attention focuses on hemispheric cups mimicking the anatomical shape of the bony acetabulum. However, the first-generation cementless hemispheric cups had a number of design flaws, which have meanwhile been attended to. We therefore never really turned away from threaded cups and began to implant a cone-shaped version of commercially pure titanium in January 1985. Introduced in January 1993, the redesigned version was unlike any other implant described in the literature in terms of its outer shape, the locking mechanism for the polyethylene liner, the cutting strength of its teeth and the thin wall of the cup shell. We wanted to know whether this implant was generally applicable for all primary THRs irrespective of the underlying anatomy, i.e. whether the exclusive consecutive use of this implant was justified.

Method: Between 1/1/1993 and 30/4/1994, 332 patients underwent primary surgery for osteoarthritis with threaded cups and titanium stems. These self-tapping double-cone cups made of pure titanium feature sharply cutting teeth for anchorage without screws. The PE liner locks into the titanium shell by a 4-level conical locking mechanism obviating the need for indentations for rotational adjustment of the liner. All cups and stems implanted during this period were uncemented. At 10 years plus, clinical and monitor-controlled radiologic follow-ups were conducted to evaluate changes in cup position, radiolucent lines, osseo-integration and revisions.

Results: 209 patients (63 males and 146 females; mean age at surgery: 62.6 years, range: 18.9 to 83.2 years) showed up for follow-up. 71 were dead, 36 without revisions were contacted by phone, 10 were lost to follow-up. The mean follow-up time was 10.2 years (range: 10.0 to 11.1 years). 2 patients had undergone cup revision, one for low-grade infection after 9.6 years and one for cup fracture after 5 years. With cup revision as the endpoint, the Kaplan-Meier survival rate was 99,2 % (CI: 96.6 to 99.8). Radiography showed altered cup inclination in two patients and radiolucent lines signalling absence of osseointegration in one patient. All other implants were stable clinically and radiologically. Gaps between the cup floor and the bone tended to be spontaneously obliterated by newly formed bone. Complete obliteration was observed even in cases with incomplete cranial implant coverage due to hip dysplasia.

Conclusion: The outcome of threaded double-cone cups at 10 years and more compares well with the best results achieved with other implants, particularly hemispheric cups. This documents that their unique design features have so far stood the test of time. It also shows that these cups have a place in all patients candidates for primary total hip arthroplasty.

Introduction: Cementless tapered straight stems of the first generation were introduced in 1979, those of the second generation in 1986. For further perfection SL-PLUS stems were introduced in early 1993. These were redesigned proximally and featured slimmer necks for a larger range of motion, a central trochanteric pull-out thread and a larger surface area in the proximal stem third.

Method: Between 01/01/1993 and 31/03/1994 339 patients were implanted with these cementless new-generation stems. In the period under review no stems other than these, e.g. cemented implants or other implant systems, were used in primary THAs.

Of the 339 patients, 218 were available for follow-up, 72 had died, 38 without revision surgery were contacted by phone and 11 were lost to follow-up.

The underlying pathology was idiopathic degenerative joint disease (153 pts.), dysplastic OA (37 pts.), femoral head necrosis (12 pts.), posttraumatic OA (6 pts.) and OA of other origins (5 pts.). To evaluate changes in stem position, radiolucent lines, osseointegration and revision, clinical and monitor-controlled radiographic follow-ups were conducted at 10 years plus.

Results: 5 patients were revised within the follow-up time because of: one aseptic loosening, one low-grade infection, two periprosthetic fractures, one traumatic subsidence.

At the 10 year follow-ups (10,0 to 11,1, mean 10,2 years) the stem position was unchanged in all of the 213 patients. The stems had been implanted in proper anatomical alignment in 196 patients, in varus in 16 and in valgus in one patient. 93 patients showed no changes of the peri-implant bone. In 96 peri-implant bone apposition was recorded in one or more zones (Gruen). 20 patients presented with radiologic evidence of both peri-implant bone apposition and some atrophy. None of these patients showed abnormalities clinically (HHS: 95.2; 76–100). At the 10-year follow-ups 2 stems had worked loose. Another 2 patients presented with intertrochan-teric osteolyses with definite progression versus the 5-year follow-up. On analysis, radiolucent lines (RLs) were seen in zone 1 in 28.6% of cases, in zones 2 and 6 in 3.3%, in zones 3, 4 and 5 in 0.5% and in zone 7 in 22.1%.

The Kaplan-Meier survival rate was 98.2% (CI 95.3 to 99.2) with revision of the stem for any reason as the end point (N = 339).

Conclusion: The outcome of this quality control study showed the stem to be universally applicable in all primary THAs so that its continued use in the indications listed is well justified.