Advice

Summary

Summary

The OSCAR 3 ultrasonic arthroplasty revision instrument is a tool to aid the removal of cement during operations to revise replacement joints. It would be used by orthopaedic surgeons, in combination with standard mechanical methods of cement removal.

Effectiveness

  • Three clinical studies reporting on the use of the OSCAR were identified: 1 retrospective case series (n=17) and 2 case reports (both n=1). Also, 2 laboratory studies were identified where the safety of the device was investigated.

  • The retrospective case series reviewed 17 hip revision cases, 13 of which were performed with the OSCAR and 3 with standard care (1 case was excluded as cementless revision.)

  • The case series found that, compared with expected osteotomy length from pre-operative planning, the OSCAR was associated with significantly shorter osteotomies (mean reduction 7 cm, p=0.001) and shorter replacement prostheses (in 8/13 cases, p=0.006). There was no statistically significant reduction in osteotomy or prosthesis length in the standard care group compared with predicted results.

  • One case report described the successful removal of a large intrapelvic mass of cement from a woman aged 83 years having hip revision.

  • No efficacy studies were found for elbow, knee or shoulder revisions.

Adverse events and safety

  • A single case report described an incident of thermal necrosis of bone caused by the OSCAR during elbow revision, resulting in post-operational radial nerve palsy and pathological fracture of the humerus.

  • No reports of adverse events using the OSCAR were found for shoulder, knee or hip revisions.

Cost and resource use

  • The 2014 costs of the OSCAR 3 include £22,550 for the generator, £4879 for the cement removal handset, £2466 for the cleaning system, and costs ranging from £103 to £154 for single-use probes and £108 to £346 for reusable probes. Annual maintenance charges also apply.

  • The OSCAR 3 system can be rented, with prices ranging from £886 for a single surgical procedure to £3309 for 1 month's use.

  • The use of the OSCAR 3 system would not be expected to impact on service provision before or after surgery.

Technical factors

  • One study found that high bone temperatures generated by the OSCAR in human bodies could be mitigated by using intermittent pulses of ultrasound and irrigating the area with chilled saline.

  • One measurement study showed that the release of potentially toxic chemicals during cement vaporisation with the OSCAR was well below occupational exposure standards.

  • One qualitative study using ex vivo femur samples found less bone loss with the OSCAR compared with cement removal by curettage. The researchers also attributed the presence of microscopic cracks in the bone to the use of ultrasound.