Conical Primary Cementless Stem in Revision Hip Arthroplasty: 94 Consecutive Implantations at a Mean Follow-Up of 12.7 years

Cementless Femoral Component in Revision Hip Arthroplasty: A Registry Comparative Study Between Primary and Revision Stems

INTRODUCTION

Femoral component choice in revision hip arthroplasty is debated. An arthroplasty registry study was designed to compare the survival rates of revision hip arthroplasties performed for femoral component failure using noncemented primary stems or noncemented revision stems, aiming to assess (1) the survival rates of primary and revision stems and (2) the survival rates of primary and revision stems, in single-taper and modular versions.

METHODS

In a regional arthroplasty registry, 5,186 revision surgeries of femoral component using noncemented stems performed on residing patients were identified: 1,127 primary stems (21.7%) and 4,069 (78.3%) revision stems. Implants were additionally categorized according to modularity. The cohorts differed for demographic and implant-related features.

RESULTS

Primary stems achieved less than 10-year survival rates than revision stems (85.9% vs. 92.3%; P < 0.0001). Primary stems achieved lower 10-year survival rates with specific end points, aseptic loosening (P = 0.0005), and periprosthetic fracture (P < 0.0001) but not primary instability (P = 0.011). The survival rates of the four cohorts stratified for modularity demonstrated different 10-year survival rates (single-taper primary stems: 84.1%; modular primary stems: 87.9%; single-taper revision stems: 94.5%; modular revision stems: 91.2%; P < 0.0001). In revision surgeries due to aseptic loosening, primary stems achieved lower survival rates, especially in women aged more than 65 years (P = 0.021). Single-taper primary stems achieved lower performances than single-taper revision stems (P < 0.001).

DISCUSSION

Primary stems should be carefully adopted in femoral component revision surgeries, especially in women aged 65 years or older. Single-taper primary stems carried a notable rate of failures at 10 years in comparison to single-taper revision stems.

LEVEL OF EVIDENCE

III, therapeutic study.

The Zweymüller primary stem is a reliable, effective, and less invasive implant in revision hip arthroplasty for Paprosky type I and II defects

Aims

Revision hip arthroplasty for femoral stem loosening remains challenging due to significant bone loss and deformities requiring specialized revision stems. The aim of this study was to evaluate the clinical and radiological outcomes, and survival, of a consecutive series of femoral revisions performed using a primary cementless stem with tapered geometry and rectangular cross-section at medium-term follow-up.

Methods

We retrospectively evaluated 113 patients (115 hips) with intraoperative Paprosky type I (n = 86) or II (n = 29) defects, who underwent femoral revision with Alloclassic Zweymüller SL stem for one-stage aseptic revision or two-stage septic revision from January 2011 to December 2020. The mean follow-up was 77.9 months (SD 33.8). Nine patients were lost to follow-up (deceased or not available), leaving 104 patients (106 hips) for the clinical and radiological analysis. Clinical assessment was performed with Harris Hip Score (HHS) and visual analogue scale (VAS) before surgery and at final follow-up.

Results

There were 60 males and 53 females with a mean age at time of surgery of 71.2 years (SD 12.6). The mean HHS and VAS significantly improved at final follow-up, from 33.7 (SD 13.0) and 5.8 (SD 1.8) preoperatively to 66.4 (SD 16.8) and 2.1 (SD 1.8) postoperatively, respectively (p = 0.001 and p = 0.001). Overall, 28 patients (25%) showed non-progressive radiolucent lines at the level of proximal femur without radiological or clinical signs of loosening. One patient had a recurrence of periprosthetic joint infection after a two-stage procedure requiring re-revision surgery. One patient underwent exchange of modular components for recurrent dislocation, and another case of dislocation was treated conservatively. The survival with aseptic loosening as endpoint was 100%, while stem revision for any reason was 99.1% at up to 152 months' follow-up.

Conclusion

Alloclassic Zweymüller SL primary stem showed favourable medium-term results and survival for revision total hip arthroplasty in Paprosky type I and II defects.

Management of Severe Bone Defects in Femoral Revision following Total Hip Arthroplasty

Treatment of femoral bone defects continues to be a challenge in revision total hip arthroplasty (THA); therefore, meticulous preoperative evaluation of patients and surgical planning are required. This review provides a concise synopsis of the etiology, classification, treatment strategy, and prosthesis selection in relation to femoral bone loss in revision THA. A search of literature was conducted for identification of research articles related to classification of bone loss, management of femoral revision, and comparison of different types of stems. Findings of a thorough review of the included articles were as follows: (1) the Paprosky classification system is used most often when defining femoral bone loss, (2) a primary-length fully coated monoblock femoral component is recommended for treatment of types I or II bone defects, (3) use of an extensively porouscoated stem and a modular fluted tapered stem is recommended for management of types III or IV bone defects, and (4) use of an impaction grafting technique is another option for improvement of bone stock, and allograft prosthesis composite and proximal femoral replacement can be applied by experienced surgeons, in selected cases, as a final salvage solution. Stems with a tapered design are gradually replacing components with a cylindrical design as the first choice for femoral revision; however, further confirmation regarding the advantages and disadvantages of modular and nonmodular stems will be required through conduct of higher-level comparative studies.

Cementless Primary Stems in Revision Hip Arthroplasty: A Narrative Review

Cementless primary stems in revision hip arthroplasties may be conservative options to preserve bone stock and provide adequate reconstruction of the hip biomechanics. However, there is still little evidence about indications, limitations, and outcomes. This narrative review showed that conventional standard stems were adopted in different revision settings, up to Paprosky IIIA grade bone defects. In cases of acceptable metaphyseal bone stock, when a scratch fit of at least 4 cm can be achieved, a conventional cementless stem may be an adequate solution. Mid-term clinical and radiographic outcomes and survival rates were similar to long revision stems, whereas complications, surgical time, and costs were lower among conventional stems. However, unsuitable contexts for conventional stems included canal diameters larger than 18 mm and failed revision stems with cortical weakening. Even short stems can be considered in revisions, in order to preserve bone stock and stay proximal to femoral remodeling zones and bone/cement plugs. Short stems were successfully adopted up to Paprosky IIIA bone defects, achieving mid-term survival rates not inferior to long revision stems. Ageing, osteoporosis, and intraoperative femoral fractures were the main negative prognostic factors. In very select cases, a downsizing technique (from longer to shorter stems) may be adopted to simplify the procedure and reduce complications.

[Strategies for stem revision : Surgery planning, implant removal and reimplantation]

BACKGROUND AND PLANNING

Femoral revision represents a challenging procedure in its surgical planning and technical execution. The results are mainly dependent on the bone loss present, the quality of the implant removal and the choice of revision system. Patient-specific factors such as age, comorbidities, bone quality or even the localization of the cement have a decisive influence on the surgical strategy. Appropriate preoperative preparation, including the presence of the necessary special instruments, which are essential for gentle implant removal, is indispensable to achieve the best possible result.

THERAPY

A bone-sparing implant removal can be particularly challenging, especially in the case of well-fixed stems and cement residues, which may extend far beyond the isthmus. In such situations, a transfemoral approach should be considered. Cementless reimplantation using modular or non-modular titanium stems is currently the preferred treatment of choice for most revisions. In elderly, low-demand patients or with poor bone quality, cemented revision remains a good alternative treatment option.

Cementless primary or revision stem in revision hip arthroplasty for aseptic stem loosening with Paprosky type I/II femoral defect?

BACKGROUND

The use of primary or revision stem during revision total hip arthroplasty (THA) for aseptic stem loosening with Paprosky type I/II femoral defect remains controversial. The aim of this study was to compare the outcomes of patients who underwent revision THA with a primary or revision stem.

METHODS

We retrospectively reviewed 78 patients who received revision THA for aseptic stem loosening using primary (N = 28) or revision stems (N = 50). The bone defects were classified as Paprosky type I or II. The mean follow-up duration was 72.3 ± 34.7 months. The primary outcome domains included surgical complications and implant failures. The secondary outcome domains included medical complications, 30- and 90-day readmission, and Harris hip score (HHS).

RESULTS

The use of revision stem was associated with a higher incidence than primary stem of patient complications (60.0% vs. 32.1%, p = 0.018), including intraoperative femur fracture (28.0% vs. 7.1%, p = 0.029) and greater trochanter fracture (16.0% vs. 0%, p = 0.045). The implant survival rate was comparable between groups. HHS at the final follow-up was similar.

CONCLUSION

With a lower risk of surgical complications and a similar rate of mid-term implant survival, cementless primary stem appears superior to revision stem in revision THA for aseptic stem loosening with Paprosky type I/II femoral defect.