Percutaneous bone cement refixation of aseptically loose hip prostheses: the effect of interface tissue removal on injected cement volumes

Percutaneous cementoplasty of periprosthetic aseptic hip loosening

Progressive population aging and improved healthcare have led to a significant increase in patients with hip arthroplasty (HA). In this patient group, the proportion of those who require a new arthroplasty (prosthetic replacement or secondary revision of the hip), has also increased. For this subgroup of patients in whom surgical prosthetic replacement should be considered but is contraindicated, a new technique has been developed since 2010: percutaneous injection of periprosthetic cement under fluoroscopic or CT control ("femoroplasty; FMP") as an alternative and less invasive treatment compared to surgery to stabilize the HA without replacing it, with excellent results on patients' quality of life. In this brief communication, we describe our positive experience regarding FMP, which we have performed for the first time in Spain on four patients (age range between 74-83 years, 2 female and 2 male patients, 3 right HA and 1 left HA), without post-complications. We highlight both the relative simplicity of this technique, which can be incorporated into radiological intervention even in regional hospitals, and the significant clinical improvement observed in all patients. In conclusion, we hope that our experience can contribute to the increased adoption of this innovative technique within the scientific community.

Percutaneous cementoplasty of periprosthetic loosening: can interventional radiologists offer an alternative to revision surgery?

OBJECTIVE

To evaluate feasibility and validate both safety and efficiency of radiological percutaneous periprosthetic bone cementoplasty (RPPBC) performed under local anesthesia as an alternative minimally invasive treatment of aseptic implant loosening.

METHODS

In this case series, seven patients (mean age 81 years, range 73 to 89 years, 2 men and 5 women) were enrolled between February 2011 and January 2020 with confirmed aseptic loosening of orthopedic implants. One patient presented with tibial component loosening of an unicompartmental knee arthroplasty, one with glenoid component loosening from a reverse shoulder arthroplasty, one femoral gamma nail, and four presented with pedicle screw loosening after staged posterior lumbar interbody fusion. All patients underwent clinical, biochemical, and imaging assessments to confirm the diagnosis of aseptic loosening. All benefited from RPPBC under dual CT and fluoroscopic guidance. All procedures were performed under local anesthesia by an experienced radiologist. Preprocedural, immediate and 6-month post-cementoplasty pain levels on a visual analogue scale (VAS), and functional outcomes were evaluated. Immediate and 6-month postprocedural CTs were performed to evaluate the treated region.

RESULTS

All RPPBC were well tolerated by patients throughout the procedure. None of the patients suffered from local or systemic infection post-RPPBC, or periprosthetic fractures. No recurrent implant loosening was observed. Six patients were pain free at 6 months. All patients expressed functional improvements during validated outcome score evaluations.

CONCLUSION

RPPBC appears to be an efficient and reliable treatment strategy for aseptic loosening of orthopedic implants in elderly patients deemed unfit for revision surgery.

KEY POINTS

• Radiological percutaneous periprosthetic bone cementoplasty offers immediate and long-lasting pain relief in elderly frail patients, or those deemed unfit for revision surgery despite presenting with symptomatic aseptic loosening of orthopedic implants. • Radiological percutaneous periprosthetic bone cementoplasty brings quick and long-lasting improvements in clinical functional outcomes and offer effective pain reduction, thereby improving the overall quality of life. • Radiological percutaneous periprosthetic bone cementoplasty is a safe, quick, reliable, and well-tolerated minimally invasive procedure which can be easily performed under simple locoregional anesthesia and requires short-term hospital stay.

Water Jet Applicator for Interface Tissue Removal in Minimally Invasive Hip Refixation: Testing the Principle and Design of Prototype

Mechanical loosening of implants is in the majority accompanied with a periprosthetic interface membrane, which has to be removed during revision surgery. The same is true if a minimal invasive (percutaneous) refixation of a loose implant is done. We describe the requirements for a waterjet applicator for interface tissue removal for this percutaneous hip refixation technique. The technical requirements were either obtained from a literature review, a theoretical analysis, or by experimental setup. Based on the requirements, a waterjet applicator is designed which is basically a flexible tube (outer diameter 3 mm) with two channels. One channel for the water supply (diameter 0.9 mm) and one for suction to evacuate water and morcellated interface tissue from the periprosthetic cavity. The applicator has a rigid tip (length 6 mm), which directs the water flow to create two waterjets (diameter 0.2 mm), both focused into the suction channel. The functionality of this new applicator is demonstrated by testing a prototype of the applicator tip in an in vitro experimental setup. This testing has shown that the designed applicator for interface tissue removal will eliminate the risk of water pressure buildup; the ejected water was immediately evacuated from the periprosthetic cavity. Blocking of the suction opening was prevented because the jets cut through interface tissue that gets in front of the suction channel. Although further development of the water applicator is necessary, the presented design of the applicator is suitable for interface tissue removal in a minimally invasive hip refixation procedure.

A fluoroscopy-based planning and guidance software tool for minimally invasive hip refixation by cement injection

Purpose

In orthopaedics, minimally invasive injection of bone cement is an established technique. We present HipRFX, a software tool for planning and guiding a cement injection procedure for stabilizing a loosening hip prosthesis. HipRFX works by analysing a pre-operative CT and intraoperative C-arm fluoroscopic images.

Methods

HipRFX simulates the intraoperative fluoroscopic views that a surgeon would see on a display panel. Structures are rendered by modelling their X-ray attenuation. These are then compared to actual fluoroscopic images which allow cement volumes to be estimated. Five human cadaver legs were used to validate the software in conjunction with real percutaneous cement injection into artificially created periprothetic lesions.

Results

Based on intraoperatively obtained fluoroscopic images, our software was able to estimate the cement volume that reached the pre-operatively planned targets. The actual median target lesion volume was 3.58 ml (range 3.17–4.64 ml). The median error in computed cement filling, as a percentage of target volume, was 5.3 % (range 2.2–14.8 %). Cement filling was between 17.6 and 55.4 % (median 51.8 %).

Conclusions

As a proof of concept, HipRFX was capable of simulating intraoperative fluoroscopic C-arm images. Furthermore, it provided estimates of the fraction of injected cement deposited at its intended target location, as opposed to cement that leaked away. This level of knowledge is usually unavailable to the surgeon viewing a fluoroscopic image and may aid in evaluating the success of a percutaneous cement injection intervention.