Introduction: Revision surgery for stem loosening and peri-implant bone loss of variable extent is a major challenge for orthopedic surgeons. Our strategy has been to use cementless straight stems of rectangular cross-section for revisions. To ascertain the value of this implant we analyzed the results at a minimum follow-up of 10 years.

Material and Method: Between October 1991 and end 1998, 125 patients (134 hips) underwent revision surgery. Of these, 39 were males and 86 were females. Sixty-seven of the original implants were cemented and as many were cementless. Cementless revision stems (SLR; Plus Orthopedics, Aarau, Switzerland) size 3 to 11 (180 to 223 mm in length) were used for revisions. Patient age at the time of surgery was 37.8 to 89.3 (mean, 71.0) years.

Fifty patients (53 hips) died post revision 0.0 to 13.5 (mean, 6.8) years. Their implants had been followed-up radiographically for 0.0 to 9.2 (mean, 3.6) years. At the time of revision these patients had been 48.9 to 89.3 (mean, 76.7) years old. One of them had undergone stem revision for aseptic loosening one year post surgery. Another 6 were revised 1.4 to 13.9 years post surgery, 5 for low grade infection and 1 for peri-implant fracture.

Seven patients refused to present for follow-up because of advanced age and poor cooperation. Eight were contacted by telephone. These 15 patients were not re-operated. Five patients were altogether lost to follow-up, thus leaving a total of 53 hips (49 patients) for analysis at a follow-up time of at least 10 years. The follow-up time was 10.0 to 16.1 (mean, 11.6) years.

For radiographic follow-ups monitor-guided a.-p. and axial radiographs were recorded. These were analyzed by Gruen zones.

Results: All stems were properly aligned along the long femoral axis, except in 1 patient, who had sustained a peri-implant fracture during a fall with axial stem subsidence responding to conservative treatment. In 38 patients peri-implant bone apposition was detected in all 7 Gruen zones. This was combined with bone resorption in other zones in 2 patients. Four patients presented with osteolytic lesions. In one of them with metal-on-metal articulating surfaces, the lesion extended to several segments and will necessitate revision. All other stems were stable. None of them was at risk.

Conclusion: This analysis showed that the SLR revision stem performs well for an intermediate follow-up time of at least 10 years.

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.

Introduction: Stable cup anchorage in dysplastic hips is a key problem of THA. The pupose of this study was to evaluate the usefulness of a cementless cup without acetabuloplasty based on medium term Results: Method 53 patients, 47 females and 6 males aged 20 to 76 (mean 49) years at surgery were followed-up after 4.9 to 11.4 (mean 8.8) years. Crowe’s dysplasia classification showed 30 hips to be grade I, 23 grade II and 1 grade III pre-operatively. All patients were implanted with threaded pure-titanium double-cone cups. Acetabuloplasty was omitted and care was taken to achieve primary stability in the bone stock available. Pre-operative leg length discrepancy versus contralateral was 0 to 7 (mean 3.9) cm.

Results: On postoperative radiography 45 cups were completely covered by bone in position I. Of 6 cups 3 quarters were covered, of 1 cup 2 thirds and of another one ½ of the cranial circumference. All of the incompletely covered cups were stable at follow-up. Altogether 51 cups had maintained their position by radiographic evidence and were firmly anchored in bone. Cup loosening in Crowe grade I and II necessitated 2 revisions. Leg length was equalized in 39 patients with mean lengthening by 3.4 (1.2 to 4.5) cm.

Conclusion: In the management of dysplastic hips the system used provides stable anchorage in the bone stock without additional acetabuloplasty. Even pronounced soft tissue tension on substantial leg lengthening does not impair implant stability.

Summary: Primary stable implantation of a cementless titanium cup in hip dysplastia cases without additional acetabuloplasty is achieving good medium term results.