Long term results with the interlocking uncemented long stem in revision hip arthroplasty: a mean 15-year follow-up

Revision of total hip arthroplasty by long locking stem with fully hydroxyapatite-coated modular metaphysis (Reef™): A continuous series of 78 cases at a minimum 2-year follow-up

INTRODUCTION

Since the Wagner and Vives stems were introduced in the 1980s, the range of uncemented implants for femoral revision has grown with increasing demand. Cementless modular implants with a wide range of lengths and diameters improved adaptation to the bone and secondary metaphyseal integration. Data are sparse for the Reef™ locking stem (Depuy-Synthes, Saint-Priest, France) and we therefore conducted a retrospective study at more than 2 years' follow-up, in a continuous series of total hip arthroplasty (THR) revision procedures using this long fully-hydroxyapatite-coated modular locking stem, assessing (1) implant survival, (2) clinical and functional results, and (3) radiographic results.

HYPOTHESIS

The study hypothesis was that all-cause≥2-year survival is>90%.

PATIENTS AND METHODS

Between 2007 and 2018, 413 femoral stem exchanges were performed in our center, a Reef™ model being needed in 93 cases. Etiologies comprised: Vancouver B2 or B3 periprosthetic fracture (57%, n=53), aseptic loosening (33%, n=30), septic loosening (10%, n=9) and 1 case of aseptic non-union under the stem (1%, n=1). Clinical and functional assessment used Harris Hip Score (HHS), Postel Merle d'Aubigné score (PMA) and Oxford-12 Hip Score (OHS). Radiographic assessment used immediate postoperative views and last follow-up radiographs, assessing osseointegration, filling index and stress shielding. Implant survival was estimated following Kaplan-Meier with 95% confidence intervals.

RESULTS

Mean follow-up was 6±3 years (range, 2-12). Last follow-up included 78 cases for analysis (12 deaths [13%] and 3 patients lost to follow-up before 2 years [3%]). Ten-year Reef™ implant survival was 98.7% (95% CI: 96.3-100) free of aseptic loosening (n=1) and 94% (95% CI: 87-100) for all causes (n=3). The failures related to aseptic loosening involved femoral stem fracture away from the modular part; the 2 cases of septic loosening did not undergo reimplantation for medical reasons. Preoperatively (scheduled surgeries, excluding periprosthetic fractures: n=40), mean HHS was 43±12 and 77±12 at last follow-up (81±13 in scheduled surgery [n=40] and 73±11 in emergency surgery for periprosthetic fracture [n=53]), mean PMA score was 13±2 and mean OHS was 26±9. The infection rate was 11% (n=9) including 7.6% new infection (n=6). The dislocation rate was 6% (n=5). The radiographic stress shielding rate was 11% (n=9) and significantly associated with low metaphyseal filling index (76±7% vs. 83±8% [p=0.009]).

DISCUSSION

Like other recent data, the present good survival results support the trend for uncemented stems in femoral revision, as encouraged by the 1999 symposium of the French Society of Orthopedic Surgery and Traumatology (SoFCOT). Primary diaphyseal fixation enables secondary metaphyseal integration on an implant with modularity ensuring good bone adaptation. Close contact between the bone and hydroxyapatite surfaces is a key-point in the surgical strategy.

LEVEL OF EVIDENCE

IV, retrospective study.

Influence of Geometry and Extent of Coating on Survival of Cementless Distal-Locking Revision Stems at 7 to 18 Years

BACKGROUND

We aimed to compare the long-term clinical outcomes, complications, and survival of 2 revision stems with different geometries, extents of coating, and distal-locking mechanisms.

METHODS

We retrospectively compared outcomes at a minimum of 7 years following revision THA using 2 proximally coated distal-locking stems: 98 Ultime first-generation (G1) and 116 Linea second-generation (G2) stems. Ten-year Kaplan-Meier survival was assessed considering stem re-revision for any reason and for aseptic reasons. At final follow-up, Harris Hip Score and Oxford Hip Score were collected, and any thigh pain or complications were noted.

RESULTS

Considering re-revision for any reason, survival was 69% for G1 stems and 91% for G2 stems. Considering re-revision for aseptic reasons, survival was 77% for G1 stems and 92% for G2 stems. Re-revisions were due to fracture of 6 G1 stems but no G2 stems. Complications that required reoperation without stem or cup removal occurred in 3 of the G1 stems and 1 of the G2 stems. Compared to the G1 stems, the G2 stems resulted in better Harris Hip Score (83 vs 71, P = .001), Oxford Hip Score (22 vs 27, P = .019), less thigh pain (4% vs 39%, P < .001), and fewer nonoperated complications (9% vs 15%).

CONCLUSION

The second-generation stem had significantly better survival and clinical outcomes than the first-generation stem. The differences in survival and clinical outcomes could be attributed to the larger coated surface of the G2 stem and to the fact that the G1 stem was originally intended as a temporary implant to be followed by de-escalation.

Management of Vancouver B2 and B3 Periprosthetic Proximal Femoral Fractures by Distal Locking Femoral Stem (Cannulok) in Patients 75 Years and Older

BACKGROUND

Periprosthetic fracture following total hip arthroplasty is a significant problem faced by hip surgeons, and its management in elderly patients remains a considerable challenge.

METHODS

We retrospectively reviewed 28 Vancouver B2 and B3 periprosthetic femoral fractures (PFF) treated with revision of the femoral stems by distally locked, hydroxyapatite-coated uncemented stems (Cannulok). Patients were aged 75 years or older at the time of surgery.

RESULTS

The mean follow-up was 44.6 months (range, 24-102). The mean postoperative Oxford hip score was 30.1 (range, 10-46). The rate of fracture union was 95.8%, and the survivorship of the stem was 100% at the end of follow-up.

CONCLUSION

The management of PFF in elderly is associated with increased postoperative morbidity and mortality. The use of a distally locked, hydroxyapatite-coated femoral stem is a valid option for the treatment of PFF to achieve fracture union with a low rate of revision.