High medium-term survival of Zweymüller SLR-plus stem used in femoral revision

Abstract

Revision after failed THA resulting from loosening of the femoral component can be challenging even for experienced surgeons. Aseptic loosening usually is associated with some degree of bone loss. We asked whether the Zweymüller SLR-Plus((R)), along with allograft reconstruction of the deficient femoral bone stock, would provide survivorship, osseointegration, and stability similar to or better than previously reported implants for femoral revision. We retrospectively reviewed 69 selected patients (70 hips) who underwent revision of the femoral component using the SLR-Plus((R)) stem during a 10-year period. The indications for revision included aseptic and septic failure of biologic fixation, incorrect implantation, and periprosthetic fracture. Seven patients died and four were lost to followup. Fifty-eight of the 69 patients (59 hips) were available at a mean 8.3 +/- 2.7 years (range, 4-14 years) after revision surgery. There were 14 men and 44 women (mean age, 69 years; range, 42-89 years). Four stems (7%) were rerevised. With rerevision for aseptic reasons, the survival at 10 years was 95% (95% confidence interval, 86%-98%). No femoral periprosthetic osteolysis occurred around the stem and 91% of stems appeared stable radiographically (osseointegration, fibrous). Based on the survival data, we believe the SLR-Plus((R)) stems are reliable for patients undergoing hip revision surgery with central bone loss.

Level of evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Fig. 1

The Zweymüller SLR-Plus^® cementless titanium stem for femoral revision has a dual-tapered rectangular shape that addresses the issue of initial secure axial positioning and rotational stability and is available in lengths of 181 to 227 mm.

Fig. 2

The survivorship of the SLR-Plus^® stem at 10 years according to the Kaplan-Meier method is 94% (95% CI, 84%–98%) with removal of the stem for any cause as the end point.

Fig. 3

The survivorship of the SLR-Plus^® stem at 10 years according to the Kaplan-Meier method increases to 95% (95% CI, 86%–98%) with removal of the stem resulting from aseptic loosening as the end point.

Fig. 4

The survivorship of the SLR-Plus^® stem at 10 years according to the Kaplan-Meier method decreases to 86% (95% CI, 72%–93%) with the worst-case scenario (removal of the stem and counting patients lost to followup as having failed results) as the end point.

Fig. 5

This graph shows the number of hips at risk at each interval.

Fig. 6A–B

(A) In this postoperative radiograph of an SLR-Plus^® stem implanted in a 69 year old man, the stem is in full contact with the femoral canal. (B) After 31/2 years followup, loosening of the stem was evident. The arrows indicate the radiolucent areas around the proximal 2/3 of the stem.

Fig. 7

Results of the clinical evaluation according to the SF-36 Health Survey are shown in the graph. All eight domains of the SF-36 Health Survey were improved at the latest followup. The percentage of improvement is shown at the upper part of the graph. (GH = General Health; PF = Physical Functioning; BP = Bodily Pain; VT = Vitality; MH = Mental Health; SF = Social Functioning; RP = Role-Physical; RE = Role-Emotional).