Étude à cinq ans de recul d’une tige anatomique revêtue d’hydroxyapatite

Do all anatomic stems perform equally at long-term survival? A regional registry-based study on 12,010 total hip arthroplasty implants according to stem length and neck modularity

BACKGROUND

Anatomic stems for total hip arthroplasty (THA) have been developed to achieve a precise geometric fit between the implant and the surrounding femoral bone, aiming at the improvement of primary stability of cementless implants until osteointegration occurs. The aim of the current study is to go over the regional Registry of Orthopaedic Prosthetic Implants (RIPO) to analyze survivorship of THA implants when anatomic stems are used; moreover, separate analysis for modular and nonmodular stems, and in standard and short implants, is presented.

MATERIALS AND METHODS

This retrospective registry study involved the analysis of data collected by the RIPO registry between 2000 and 2019. The study focused on THAs performed for primary hip osteoarthritis (OA) between 2000 and 2019. All patients treated by THA within this time frame and officially registered in the RIPO registry were included in the study. Exclusion criteria were: revision THAs, cemented implants, hemiarthroplasties, resurfacing procedures, megaprostheses for neoplastic and non-neoplastic conditions, and THAs performed on patients residing outside the region.

RESULTS

A total of 12,010 cementless primary THAs using curved anatomic stems were performed in Emilia-Romagna between 2000 and 2019 and formally registered in the RIPO registry. The overall survival rate for anatomic standard stems was 96.7% at 10 years (96.1-97.3%); at 15 from the surgery, the survival rate dropped to 95.1% (93.9-96.1%). A total of 473 out of 12,010 recorded THA with anatomic stems (3.93%) experienced failure requiring revision surgery. The fixed standard stem showed the lowest failure rate (0.6%), while modular short stems had the highest (7.4%) at long-term follow-up. The most common stem-related complication was periprosthetic fracture (PF) in short stems (2.0% of cases) while in standard stems it was implant breakage (0.9% of cases); PFs were significantly more frequent in female patients (p = 0.0082), with a relative risk (RR) of 1.59 compared with male patients. Implant breakage demonstrated the highest rate of incidence among standard-modular stems (1.1% of cases).

CONCLUSIONS

This registry-based study highlights that stem length and modularity significantly affect the long-term survival of anatomic femoral stems in THA. Fixed standard stems had the lowest failure rates, while modular short stems showed the highest failure rates and complications.

LEVEL OF EVIDENCE: 3

Distal femoral cortical hypertrophy not associated with thigh pain using a short stem femoral implant

BACKGROUND

Thigh pain following a well-fixed total hip arthroplasty (THA) remains problematic and a source of patient dissatisfaction. The purpose of this study is to evaluate if the development of distal femoral cortical hypertrophy (DFCH) is associated with postoperative thigh pain after THA.

METHODS

All patients who underwent an uncomplicated primary THA via a direct anterior approach with the Taperloc Microplasty (Zimmer Biomet, Warsaw, IN, USA) implant between 2011 and 2015 were mailed a pain drawing questionnaire. Radiographs were reviewed at 1 year minimum to determine cortical thickness change from immediate post-op. Thigh pain was compared to DFCH. 293 patients were included in the study.

RESULTS

Mean follow-up was 3.2 years. A total of 218 hips (74%) had cortical hypertrophy in Gruen zone 3 and 165 hips (56%) had cortical hypertrophy in Gruen zone 5. 52 hips (18%) had ⩾25% cortical hypertrophy in zone 3 and 91 hips (31%) had ⩾25% cortical hypertrophy in zone 5. A total of 44 patients (15%) reported anterior thigh pain and 43 patients (15%) reported lateral thigh pain. Development of DFCH in either Gruen zone 3 or 5 was not associated with anterior or lateral thigh pain. Stem size was positively correlated with zone 3 hypertrophy and inversely related to zone 5 hypertrophy. Thigh pain was not associated with patient age, gender, activity level or stem size.

CONCLUSIONS

The development of distal femoral cortical hypertrophy after THA with a short stem implant was high, but not associated with patient-reported anterior or lateral thigh pain.

Does femoral morphology and stem alignment influence outcomes of cementless total hip arthroplasty with proximally coated double-tapered titanium stems?

INTRODUCTION

Stem subsidence and thigh pain can cause significant patient dissatisfaction after cementless THA. The purpose of this study was to examine the effect of proximal-femoral morphology and stem alignment on clinical outcomes using a double-tapered, cementless titanium femoral component.

METHODS

We retrospectively reviewed 281 consecutive, primary THAs from 2012 to 2014 with a mean follow-up of 4 years. Preoperative radiographs were used to assess femoral neck shaft angle (FNS), canal flare index (CFI), Dorr classification, and greater trochanter (GT) overhang. Postoperative radiographs were used to determine stem alignment and 6-week follow-up radiographs were used to determine subsidence. Clinical outcomes included thigh pain, leg-length discrepancy (LLD), patient-reported outcome measures (PROMs) and revision surgeries.

RESULTS

271 stems (96%) did not subside (<4 mm) and 10 (4%) showed evidence of subsidence (>4 mm). Subsidence was significantly associated with subsequent revision surgery (p < 0.01). 278 stems (99%) were in neutral alignment and 3 in varus (1%). Alignment did not significantly influence subsidence, thigh pain, LLD, revisions, or PROMs. Femoral morphology measures (FNS, CFI, Dorr classification, and GT overhang) were not significantly associated with stem alignment, subsidence, LLD, or revisions. CFI was significantly associated with intraoperative calcar fractures (p = 0.02). GT overhang was associated with thigh pain (p = 0.03) and FNS was inversely associated with postoperative HOOS scores.

CONCLUSIONS

Subsidence and proximal-femoral morphology are potential sources of postoperative morbidity in certain cementless THA patients. In accordance with prior studies, CFI was identified as a potential risk factor for intraoperative calcar fractures. More research into preoperative femoral morphologies, such as GT overhang and FNS, is warranted as these may contribute to unsatisfactory results related to cementless THA.

Radiographic alterations in short-stem total hip arthroplasty: a 2-year follow-up study of 216 cases

INTRODUCTION

In recent years a variety of short-stems have been introduced. Stable osteointegration is a key factor for a satisfactory long-term result. The purpose of this study was to evaluate postoperative radiological alterations and subsidence, as a result of using a newly developed device, over a 2-year follow-up.

METHODS

216 short-stems were implanted in combination with a cementless cup. Patients were allowed full weight-bearing on the first day postoperatively. Pre- and postoperative x-rays were done using a standardised technique. Radiological alterations, such as bone resorption, radiolucency, osteolysis and cortical hypertrophy were detected and located using modified Gruen zones, and subsidence was measured via a conventional digital technique over a 2-year follow-up. In addition, Harris Hip Score (HHS), rest pain and load pain on the visual analogue scale (VAS) were assessed respectively.

RESULTS

At 2-year follow-up 6 stems (2.9%) showed nonprogressive radiolucent lines with a maximum width of 2 mm. Resorption of femoral bone stock was detected in a total of 8 cases (3.9%). Femoral cortical hypertrophy was seen in a total of 9 hips (4.4%). No patient showed osteolysis. A measureable subsidence of at least 2 mm was observed in a total of 15.7% (32 cases) after 6 weeks, corresponding to an initial settlement given full weight-bearing ambulation. Only 1.1% (2 cases) showed further progression at the 6-month follow-up, whereas at the 1- and 2-year follow-ups no further subsidence was observed. After 2 years HHS was 98.1 (65.0-100.0), rest pain on the VAS was 0.2 (0.0-7.0) while load pain was 0.4 (0.0-7.0).

CONCLUSIONS

The results of this radiographic analysis give support to the principle of using metaphyseal anchoring, calcar guided short-stems. The low incidence of bony alterations after a follow-up of 2 years indicates a physiological load distribution. After mild initial subsidence a stable osteointegration can be achieved over time.

High 10-year survival rate with an anatomic cementless stem (SPS)

BACKGROUND

Proximal cementless fixation using anatomic stems reportedly increases femoral fit and avoids stress-shielding. However, thigh pain was reported with the early stem designs. Therefore, a new anatomic cementless stem design was based on an average three-dimensional metaphyseal femoral shape. However, it is unclear whether this stem reduces the incidence of thigh pain.

QUESTIONS/PURPOSES

We asked whether this stem design was associated with a low incidence of thigh pain and provided durable fixation and high function.

METHODS

One hundred seventy-one patients (176 THAs) who had the anatomic proximal hydroxyapatite-coated stem implanted were reviewed. Eleven (6%) patients were lost to followup and 34 (20%) died without revision surgery. We used the Harris hip score (HHS) to assess pain and function. We evaluated femoral stem fixation and stability with the score of Engh et al. and also calculated a 10-year survival analysis. We assessed 126 patients (131 hips) at a mean followup of 10 years (range, 8-11 years)

RESULTS

At last followup, two patients described slight thigh pain that did not limit their physical activities. All stems appeared radiographically stable and one stem was graded nonintegrated but stable. Five patients had revision surgery: one on the femoral side (for posttraumatic fracture) and four on the acetabular side. Considering stem revision for aseptic loosening as the end point, survivorship was 100% (range, 95.4%-99.9%) at 10 years.

CONCLUSION

This anatomic cementless design using only metaphyseal fixation with a wide mediolateral flare, a sagittal curvature, and torsion, allowed durable proximal stem stability and fixation.