Influence of dual-mobility acetabular implants on revision and survivorship of cup and Kerboull-type reinforcement ring constructs in aseptic acetabular loosening

New comprehensive score for predicting difficulties in revision total hip arthroplasty

BACKGROUND

Revision total hip arthroplasty (THA) can be complex, and assessing possible difficulties is important to predict the operative time. No simple score for predicting difficulties has been assessed prospectively. We therefore developed an original score for the pre-operative evaluation of extraction and reconstruction difficulties. The objectives of this prospective study were to (1) assess correlations between score values and operative time, (2) determine whether the score predicted the need for revision implants and/or filling material, (3) determine whether the score predicted intra-operative and post-operative complications, and (4) evaluate the inter-observer and intra-observer reproducibility of the score.

HYPOTHESIS

The score is reproducible and correlates well with the operative time, thereby allowing prediction of this parameter before surgery.

MATERIAL AND METHODS

A prospective study of 103 revision THA procedures performed between March 2018 and August 2023 was conducted. The primary outcome was operative time and the secondary outcomes were use of a revision implant, use of filling material, and intra-operative and post-operative complications. The score was determined by four observers to allow evaluation of inter-observer agreement. Intra-observer agreement was assessed by having one of the observers determine the score a second time after inclusion of the last patient. The score has a maximum value of 20 and allows classification of the procedure as very difficult, difficult, and moderately difficult.

RESULTS

Mean operative time correlated with the score value: 136.0 ± 33.9 min in the very difficult group, 102.0 ± 34.8 min in the difficult group, and 75.4 ± 65.5 min in the moderately difficult group (p = 0.0002). The score predicted the use of a reinforcement ring (40 procedures: 12/17 [70%], 11/25 [44%], and 17/61 [28%] in the very difficult, difficult, and moderately difficult groups, respectively; p = 0.01) and of a long stem (20 procedures: 8/17 [47%], 7/25 [28%], and 5/61 [8%] patients in the very difficult, difficult, and moderately difficult groups, respectively; p < 0.001). The score did not predict the use of filling material (42 procedures: 10/17 [59%], 9/25 [36%], and 23/61 [37%] in the very difficult, difficult, and moderately difficult groups, respectively; p = 0.250). The score predicted both intra-operative complications (5/17 [29%], 4/25 [16%], and 4/61 [6%] procedures in the very difficult, difficult, and moderately difficult groups, respectively; p = 0.028) and post-operative complications (4/17 [23%], 0/25 [0%], and 6/61 [9%] in the very difficult, difficult, and moderately difficult groups, respectively; p = 0.15). Inter-observer agreement was strong according to Landis-Koch criteria, with kappa values ranging from 0.70 to 0.79 [0.57-0.90]. The kappa value for intra-observer agreement was 0.74 [0.63-0.85].

DISCUSSION

This score predicts surgical difficulties by adding criteria to bone destruction, in contrast to widely used classifications for revision THA. Moreover, the score is reproducible and predicts the operative time, thus potentially playing an important role during pre-operative planning.

LEVEL OF EVIDENCE

IV; prospective observational non-comparative study.

Do the porous custom implants have a position consistent with the planning and allow anatomical reconstruction of hip center of rotation in complex acetabular revisions Paprosky III?

INTRODUCTION

In revision total hip arthroplasty (THA), the advent of porous custom-made triflange acetabular implants with 3D scan planning offers a new perspective to improve implantation accuracy and anatomical restoration of the center of rotation (COR). This issue was investigated using CT-scan as the measurement tool, but in limited series (±10 cases) and without investigating the factors that may influence errors in positioning. Therefore we performed a retrospective study aiming to: (1) assess the placement accuracy of such implants with respect to the preoperative planning, (2) examine whether the volume of bone to be resected in order to apply the implant had an impact on this accuracy, (3) assess if errors in position at surgery had any influence on function, complications and survival.

HYPOTHESIS

Preoperative planning could be accurately reproduced when implanting porous custom-made acetabular implants, and that accuracy would decrease in proportion to the volume of bone to be resected METHOD: Twenty patients undergoing THA revision with porous custom-made acetabular implants were included in this single-center retrospective study. Mean follow-up was 17.9 months ± 9.4 [2-45.1]. Preoperative planning was performed using 3D scanographic modeling. A post-operative CT scan was performed to assess implantation accuracy in terms of orientation and COR restitution. Demographic data, Oxford scores, complications and survival were recorded.

RESULTS

Mean deviation from the preoperative planning in inclination, anteversion and rotation were 4.3 ° ± 2.5, 6.1 ° ± 4.7, and 7 ° ± 4.6, respectively. Restoration of the COR showed a mean deviation of 2.1 ± 1.3 mm anteroposteriorly, 2.5 ± 2 mm mediolaterally and 2.2 ± 1.3 mm proximodistally. In total, 45% (9/20) of implants were positioned with perfect restoration of orientation (±10 °) and COR (±5 mm). The mean planned bone resection was 8.1 ± 4.9 cm3, with placement accuracy and COR restitution decreasing significantly when the volume of bone to be resected exceeded 2.7 cm3. One dislocation was found (5%, 1/20). Survival at last follow-up was 100%, the mean Oxford score at follow-up was 31.7 ± 7.9 [16-52], without being influenced by errors in position or COR restitution.

CONCLUSION

In total 45% of the implants restored an orientation and a COR as planned, particularly when the volume of bone to be resected is less than 2.7 cm3. Although these are complex cases with large amounts of bone loss, 3D manufacturing could give us hope of greater precision. The link between better precision and low bone resection volume could be an area to develop with the manufacturer in order to improve results.

LEVEL OF EVIDENCE

III; diagnostic using CT in transversal retrospective study.

Use of dual mobility cup cemented into a tantalum acetabular shell for hip revision with large bone loss can decrease dislocation risk without increasing the risk of mechanical failure

BACKGROUND

Porous tantalum components and augments have demonstrated short to midterm fixation stability in acetabular total hip arthroplasty (THA) revision but do not offer a novel option to decrease the postoperative dislocation rate. Recently, dual mobility (DM) cups have gained interest to decrease the prevalence of recurrent hip instability after revision hip arthroplasty, but this issue was not confirmed combined with use of tantalum reconstruction devices. Therefore, we did a retrospective study aiming to: (1) evaluate at a 5-year minimum follow-up period the dislocation rate (and other intra- and postoperative complications), (2) assess radiographic results specifically looking at osseointegration and restoration of the hip center, (3) and also clinical results in a cohort of patients who underwent complex acetabular reconstruction with trabecular metal revision components associated with a cemented DM socket.

HYPOTHESIS

Using a DM socket cemented in porous tantalum components can reach the low risk of hip dislocation reported with DM components in revision setting without increasing the risk of a mechanical failure.

METHODS

A cross-sectional study identified 174 THA revision including an acetabular revision. Were excluded 118 revisions with acetabular defects Type 1, 2a or 2B according to Paprosky's classification, as well as 18 hips revised without a dual mobility and 3 patients (3 hips) lost to follow-up. Were thus included in this study 35 hips (35 patients) implanted with uncemented total hip arthroplasty revision using both trabecular metal acetabular cup-cage reconstruction and a cemented DM cup. Seven hips were classified Paprosky types 2C, 15 type 3A and 13 types 3B. Patients were followed with clinical and radiological evaluation regarding dislocation rate, infection, reoperation or re-revision, osseointegration and restoration of the hip center, and functional results according to the Harris hip score and psoas impingement presence.

RESULTS

At a mean follow-up of 8.1±1.8 years (5.1-12.6), one dislocation was recorded, and one acute deep infection. No patient required a cup re-revision for septic or aseptic loosening. The survivorship at 8years regarding revision for any cause as an endpoint was 96.5% (CI95%: 92-99). Osseointegration of TM implants was analyzed and found no acetabular migration at the last follow-up in the cohort. The mean hip center position was optimized from 48±7mm (37-58) to 34±5mm (29-39) vertically and from 26±5mm (-18-36) to 24±8mm (7-31) horizontally without reaching significance (p=0.1). On the last follow-up X-rays, the mean acetabular inclination was 47̊±9̊ (32̊-61̊). According to the criteria of Hirakawa, 97.1% (34/35) of the hip centers were restored. One cup (2.9%) was more than 5mm proximally from the hip center, and none more than 10mm. Clinical results assessed a Harris Hip Score improved from 36±17 (23-62) preoperatively to 82±15 (69-93) at last follow-up (p<0.0001). Two patients (2/35, 5.7%) complained of psoas impingement.

CONCLUSION

This study suggests effectiveness of DM cups in association with a tantalum-made acetabular shell for reconstruction of large bone defect in THRs for both solving postoperative instability and aseptic loosening without increasing the re-revision rate for any reason in a midterm follow-up.

LEVEL OF EVIDENCE

IV; observational study.

Single-use versus reusable ancillaries for dual mobility cup in total hip replacement. A prospective randomized short-term safety and feasibility comparison

BACKGROUND

Single-use (SU) ancillaries for cup preparation in total hip arthroplasty (THR) aim to reduce the costs of hip replacement surgery. These devices have been recently introduced, but their safety and feasibility have not been studied. Therefore, we performed a prospective randomized study aiming to assess the impact in our department of using these SU ancillaries versus standard reusable ancillaries for dual mobility THR regarding 1) the cost, 2) operative time, 3) quality of primary fixation.

HYPOTHESIS

We hypothesized that the use of SU ancillaries for acetabular preparation would reduce maintenance costs, and so optimise the operating procedure, reduce the overall cost of surgery, save time, while maintaining the same quality of prosthesis fitting.

METHOD

We conducted a randomised, controlled, open-label, two-arm, single-centre, prospective therapeutic trial with a medico-economic objective. Inclusions were made prospectively from patients hospitalised and surgically managed in our department for arthrosis over 18 years old treated with dual mobility THR.

RESULTS

In the current study, 18/20 (90%) of the cases required the use of one SU reamer when using SU ancillaries. Only two cases (10%) required a second SU reamer (without SU failure regarding the acetabular implant) because there was too much subchondral bone left and not enough cancellous bone allowing correct cup fitting. We also found that the test implant supplied in the SU kit had a less secure press-fit than the reusable metal test implants. There was one of primary press-fit failure in the SU group requiring a different cup with additional screws. The estimated cost to the supplier per procedure was 20,105 euros using single-use reamers versus 26,666 euros using conventional ancillary kits, a saving of 6561 euros (p<0.001). For the healthcare institution, the median price per intervention on the differentiating points was 2648 euros versus 2580 euros, with no significant difference (p=0.297). The results show an average societal cost of 52,199 euros using single-use and 53,572 euros using reusable ancillary equipment, with a significant difference between the two groups (p<0.003). The average cost of Healthcare Risk Waste (HCRW) disposal in the SU group was 5.2 euros per intervention against 5.1 euros in the RU group, without significant difference (p=0.910). We found a similar result for the cost of disposal of non-HCRW waste per procedure: 0.37 euros in the SU group versus 0.34 in the RU group, without significant difference (p=0.345).

CONCLUSION

SU ancillaries significantly reduce the table set up time and have the potential to facilitate time and cost savings but further research is needed in this direction. Our study shows that the daily workload, operating times, and the number of boxes of instruments to be sterilised are decreased. The associated environmental gain is significant. Nevertheless, the economic promise of these SU ancillaries is only partially supported in this trial owing to the small number of patients. Further work will be needed to obtain a more powerful medico-economic assessment of this promising ancillary product.

LEVEL OF EVIDENCE

II; prospective randomized study.

Is Cemented Dual-Mobility Cup a Reliable Option in Primary and Revision Total Hip Arthroplasty: A Systematic Review

Background: Instability is a common complication following total hip arthroplasty (THA). The dual mobility cup (DMC) allows a reduction in the dislocation rate. The goal of this systematic review was to clarify the different uses and outcomes according to the indications of the cemented DMC (C-DMC). Methods: A systematic review was performed using the keywords "Cemented Dual Mobility Cup" or "Cemented Tripolar Cup" without a publication year limit. Of the 465 studies identified, only 56 were eligible for the study. Results: The overall number of C-DMC was 3452 in 3426 patients. The mean follow-up was 45.9 months (range 12-98.4). In most of the cases (74.5%) C-DMC was used in a revision setting. In 57.5% DMC was cemented directly into the bone, in 39.6% into an acetabular reinforcement and in 3.2% into a pre-existing cup. The overall dislocation rate was 2.9%. The most frequent postoperative complications were periprosthetic infections (2%); aseptic loosening (1.1%) and mechanical failure (0.5%). The overall revision rate was 4.4%. The average survival rate of C-DMC at the last follow-up was 93.5%. Conclusions: C-DMC represents an effective treatment option to limit the risk of dislocations and complications for both primary and revision surgery. C-DMC has good clinical outcomes and a low complication rate.