FAQ & Clinical Evidences
Clinical Evidences
Established technology with proven efficacy as demonstrated by many studies.
NICE
National Institute for Health and Care Excellence
Medtech innovation briefing [MIB13]
The OSCAR 3 Ultrasonic arthroplasty revision instrument for removing bone cement during prosthetic joint revision
Birnbaum, K. and Gutknecht, N., 2010.
Lasers in medical science, 25(4). pp.595-603.
Scanning electron microscopy investigation of PMMA removal by laser irradiation (Er: YAG) in comparison with an ultrasonic system and curettage in hip joint revision arthroplasty
Smith, P.N. and Eyres, K.S., 1999.
The Journal of arthroplasty, 14(2), pp.235-238.
Safe Removal of Massive Intrapelvic Cement Using Ultrasonic Instruments
Fletcher, M., Jennings, G.J. and Warren, P.J., 2000.
Archives of orthopaedic and trauma surgery, 120(10), pp.559-561.
Ultrasonically driven instruments in the transfemoral approach–an aid to preservation of bone stock and reduction of implant length
Goldberg, S.H., Cohen, M.S., Young, M. and Bradnock, B., 2005.
JBJS, 87(3), pp.583-591.
Thermal Tissue Damage Caused by Ultrasonic Cement Removal from the Humerus
Shewale, S.B. and Briggs,R.D., 2005.
Acta orthopaedica, 76(5), pp.647-650.
Gas chromatography-mass spectroscopy analysis of emissions from cement when using ultrasonically driven tools
Frequently asked Questions
Click on one of the questions to expand text
Oscar™
Probe Stuck in Cement
This is most likely to occur when a piercer is being used. If the tip of the piercer is pushed too deeply into the cement and allowed to remain in situ, then the cement behind the tip is liable to solidify and trap the probe. If this happens, the load on the probe may be excessive preventing normal resonance because of the mass of cement now attached to the probe. If this occurs the generator will automatically enter a ‘stuck in cement’ mode and display CEMENT RELEASE MODE Energise the handset, but do not apply any pressure on the handset for the first 2 seconds of use ( this gives the channel a better chance to find a resonant feature ). The generator will perform repeated scans of the handset, sounding a double beep as it does so. Whilst this occurs, gently remove the probe from the cement. When free from cement the channel mode will return to normal operation. If the display shows WAIT – REDUCE PRESSURE just wait for 4 seconds and the module will reset automatically. Again, energise handset but apply little pressure on the handset for the first two seconds of use, then slowly remove probe.
This procedure may lead to an OVER-TEMPERATURE message on the LCD. Allow the channel to cool for several minutes. When the channel resets attempt removal again. This process may take a couple of attempts, depending how deep the probe is stuck in the cement.
Metal Fatigue
This can occur if the probe comes into contact with metal and becomes scratched, causing a stress riser to appear. When this happens, fragments of the probe are at risk of coming off during operation.
Solution: Change the probe and replace at the earliest opportunity.
Intermittent Powe During Operation
If the handset/probe suffers from intermittent power and a clicking noise, caused by the tripping of relays, coming from the generator, then the cable connecting the handset to the generator will have fractured.
Solution: Change the cable associated with the defective system.
Low Power During Operation
i. The probe will appear to be working inefficiently if it is pressed too hard into the cement. The generator will alert the surgeon by sounding an alarm.
Solution: Ease of pressure to enable the probe to work at maximum efficiency always press the tip gently into the cement and use gentle force:- allow the ultrasound to do the work. Avoid excessive force at all times.
ii. Lack of power during cutting can be due to the interface between the probe and the handset being slack.
Solution: Tighten the connection using the 9mm spanner provided. The power level can also be diminished if this interface is not clean and has been damaged due to the presence of particles. Should this occur, it is necessary to re surface the interface, which can be done by Orthofix Srl.
Should the stud attached to the probe become loose, it must be returned to Orthofix Srl for repair.
iii. Loss of power when cutting cement can also be due to the crystals in the handset overheating. The crystals will heat up naturally during normal use, but if excessive force is used for prolonged periods of time this heating will affect performance. As the handset warms up its resonant frequency will drop. If the handset becomes too warm the frequency will drop out of the handsets’ working range and the channel will shut down. The LCD will display FREQUENCY TOO LOW
Solution: Use another handset and allow the hot handset to cool down. The channel will reset automatically when the handset is cool.
Oscar PRO™
Probe Stuck in Cement
This is most likely to occur when a Piercer is being used. If the tip of the Piercer is pushed too deeply into the cement and allowed to remain in situ, then the cement behind the tip is liable to solidify and trap the probe. If this happens, the load on the probe may be excessive, preventing normal resonance because of the mass of cement now attached to the probe. An error message will appear on the generator screen warning the user about probe in ‘stuck in cement’ mode. In order to remove the probe from cement, energize the handset but do not apply any pressure to the handset for the first 2 seconds of use (this gives the channel a better chance to find a resonant feature). The generator will perform repeated scans of the handset, sounding a double beep as it does so. Whilst this occurs, gently remove the probe from the cement. When free from cement the channel mode will return to normal operation. This procedure may lead to an OVER-TEMPERATURE message on the screen. Allow the channel to cool for several minutes or switch channels. When the channel resets, attempt removal again. This process may take a couple of attempts, depending how deep the probe is stuck in the cement.
