Advice
Technology overview
Technology overview
This briefing describes the regulated use of the technology for the indication specified, in the setting described, and with any other specific equipment referred to. It is the responsibility of healthcare professionals to check the regulatory status of any intended use of the technology in other indications and settings.
About the technology
The Orthosonics OSCAR 3 ultrasonic arthroplasty revision instrument helps the removal of polymethylmethacrylate bone cement during large joint revision procedures. The system uses ultrasound to soften the cement holding the implant in place. Bespoke probes are then deployed in sequence to collect and remove the softened cement from the host bone. The OSCAR 3 can also be used for cutting and removing bone in cementless press-fit prosthesis revision and when bone resection functionality is under development, but these functions are beyond the scope of this briefing.
The OSCAR 3 is the latest iteration of the OSCAR system. The first version of the technology was introduced to the UK between 1992 and 1993 and was analogue-based. This was superseded by the digital OSCAR II system which was phased in around 2000. The OSCAR 3 system was launched in 2009 and is described by the manufacturer as having enhanced digital components and increased efficiency compared with the OSCAR II.
CE marking
The OSCAR system was CE-marked as a Class IIb device to Orthosonics Ltd. in September 2002. The current certification for cemented and cementless arthroplasty including single-use probes is valid from February 2013 until February 2018.
Description
The OSCAR 3 consists of 3 main components:
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A portable, 2-channel ultrasound generator and control unit with illuminated liquid crystal display.
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A cement removal handset or an osteotome handset (for cementless revisions) connected via a cable encased in silicone rubber to either output channel of the generator. The osteotome handset produces reduced displacement amplitude and has a golden outer sleeve to differentiate it from the silver cement removal handset.
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A range of screw-threaded reusable or single-use probes and tools, which are attached to the appropriate handset using bespoke spanners. Cement removal probes have 5 mm threads and osteotome probes have 6 mm threads to ensure use with the correct handset.
The mains-powered ultrasound generator and control unit has 2 identical output channels, each operating at a specified frequency of 28 kilohertz and an output power of up to 150 Watts. Actual operating frequency ranges from 27.9 to 28.5 kilohertz depending on the resonant frequency of the attached handset. The generator automatically controls and adjusts delivered power in response to changing mechanical load during the cement removal procedure.
Probes can be single-use or reusable, and come in several shapes and sizes. Reusable bone cement removal tools, such as groover, scraper, piercer and acetabular probes, are included as part of the initial system. Optional additional tools include all single-use probes and:
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a slap hammer and single-use extraction probe to remove larger pieces of cement and the cement plug
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osteotome and hoe probes for cementless stem removal
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extension and reducer bars for reusable and single-use probes.
Probes are activated via a pushbutton hand switch on the main body of the handset or via an air-powered foot switch connected to a nozzle below the output socket. The probe is intended for intermittent operation (10 seconds on, 20 seconds off) with a maximum 'on time' of 30 seconds to avoid overheating. If the probe is operated for this maximum period, it can be reactivated within seconds. A countdown timer starts when the handset is activated and an activation tone rises in pitch as the timer approaches zero. An alarm sounds if excessive force is applied to the handset. If the probe is pushed too deeply into the cement and allowed to remain in situ, the cement behind the tip can solidify and trap the probe. A special cement release mode must then be used to remove the probe.
Optional components include a wheeled trolley with probe attachment and foot switch storage, and a portable ultrasound cleaning system for reusable cement removal probes. After surgical use, the handset with the contaminated probe is connected to the system and inserted into a single-use cleaning cell. The probe is activated for a user-selectable 15- or 30-second cleaning cycle to remove traces of tissue and cement and can be repeated if necessary prior to normal hospital sterilising procedures.
Intended use
The OSCAR 3 is intended to be used for removing polymethylmethacrylate bone cement during joint revisions, and for cutting and removing bone in orthopaedic applications.
Setting and intended user
The OSCAR 3 is intended to be used in orthopaedic operating theatres by surgeons trained in standard orthopaedic surgical procedures and specifically trained in the use of ultrasonic surgical instruments.
Current NHS options
Current cement removal methods used during revision arthroplasty procedures comprise mechanical techniques using specifically designed hand instruments or pneumatic power tools. These are usually used in conjunction with the OSCAR 3.
NICE is aware of the following CE-marked device that appears to fulfil a similar function to the OSCAR 3:
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Ultra-Drive 3 Ultrasonic Revision System (Biomet Orthopedics).
Costs and use of the technology
The OSCAR 3 consists of several essential or optional elements, depending on the clinical procedure that is to be performed. The NHS Supply Chain catalogue lists 63 OSCAR products. The manufacturer of the OSCAR 3, Orthosonics, has provided a list of prices valid in 2014 which include (excluding VAT):
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OSCAR 3 generator: £22,549.79
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OSCAR 3 cement removal handset: £4879.11
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OSCAR 3 cleaning system: £2465.82
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OSCAR 3 reusable probes and tools: from £108.15 to £346.08 with an expected life of 6 to 9 months or 30 to 50 operations
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OSCAR 3 single-use probes and tools: from £103.00 to £154.50.
The OSCAR 3 system should be serviced annually. This includes visual checks of probes, handsets and cables; performance testing against system specifications; and medical standard electrical safety testing. The warranty cover for year 1 is free and is £3000 for year 2, rising to £6000 for year 6 onwards. The warranty covers any breakdown and an annual maintenance service.
The OSCAR 3 system is also available to rent directly from the manufacturer. Prices quoted by the manufacturer, which include reusable but not single-use tools or the cleaning system, are:
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single use – £885.80
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1 week – £1449.21
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2 weeks – £2595.60
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3 weeks – £2866.49
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1 month – £3309.39.
It is not possible to estimate the cost associated with alternative manual cement extraction techniques because of the wide range of practices and tools employed.
Likely place in therapy
The OSCAR 3 system would be used in the revision of replacement joints. Introduction of the OSCAR 3 would not be expected to significantly change NHS patient pathways before or after the revision operation.
Specialist commentator comments
One specialist commentator advised that cement extraction during large joint revision is currently done through combined use of the OSCAR system and mechanical means. The main role of the OSCAR is to remove the cement mantle from the intramedullary canal of the femur during total hip replacement revision, and the femur or tibia during total knee replacement revision. This can prevent the need for osteotomy, protect the bone by avoiding perforation or fracture and speed up the procedure.
Another specialist commentator advised that ultrasonic cement removers such as the OSCAR system have become standard tools for cement removal alongside mechanical instruments, and that the OSCAR is most useful during hip revision for the removal of well‑fixed distal femoral cement and cement plugs distal to the prosthesis. The use of the OSCAR system reduces both the risk of femoral perforation and the need for femoral osteotomy compared with the use of mechanical instruments alone. It also allows for use of shorter femoral prostheses, thus preserving distal femoral bone.
A third specialist commentator uses OSCAR in combination with cement chisels, drills and powered burrs. OSCAR applications include removing cement from the bones of patients with osteoporosis, where the risk of perforating the femoral cortex is great, and in femora with a thin layer of cement and a sloping edge that will not engage a chisel. Its use reduces the incidence of extended trochanteric osteotomy. A lack of controlled trials of OSCAR in the evidence base may be explained by ethical concerns over conducting an osteotomy in a control patient when the use of OSCAR would make it unnecessary. In addition, patient outcomes with OSCAR can be very operator dependent, requiring skill and practice to be used effectively.
Equality considerations
NICE is committed to promoting equality and eliminating unlawful discrimination. We aim to comply fully with all legal obligations to:
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promote race and disability equality and equality of opportunity between men and women
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eliminate unlawful discrimination on grounds of race, disability, age, sex, gender reassignment, pregnancy and maternity (including women post-delivery), sexual orientation, and religion or belief, in the way we produce our guidance (these are protected characteristics under the Equality Act 2010).
The OSCAR 3 is likely to be used primarily, but not exclusively, in older people because they are more likely to need large joint revisions involving cement removal. Older people are protected under the Equality Act (2010).