Hip joint device and method
View Patent ↗A medical device for implantation in a hip joint of a patient. The medical device comprises an inner and an outer surface, wherein a contacting portion of said inner surface is spherical and adapted to face a center of the hip joint when said medical device is implanted. The medical device is adapted to receive a caput femur or a prosthetic caput femur having a spherical portion. Said medical device comprises at least one extending portion adapted to clasp the caput femur, or prosthetic caput femur, for restraining said caput femur, or said prosthetic caput femur in said medical device. The extending portion comprises an elastic portion, and the medical device is adapted to release the caput femur or prosthetic caput femur from said medical device by deflecting said at least extending portion when a predetermined strain is placed on said medical device by abnormal movement of the hip joint caused by the patient.
1. A medical device for implantation in a hip joint of a patient, wherein said medical device comprises an inner and an outer surface, wherein a contacting portion of said inner surface is spherical and adapted to face a center of the hip joint when said medical device is implanted, and wherein said medical device is adapted to receive a caput femur or a prosthetic caput femur having a spherical portion, wherein
a) said medical device comprises at least one holding member for restraining said caput femur, or said prosthetic caput femur in said medical device,
b) said at least one holding member is slidable in a direction more transversal to than parallel with a center axis of a collum femur, and wherein
c) said medical device is adapted to release the caput femur or prosthetic caput femur from said medical device by sliding said at least one holding member away from the center axis of the collum femur when a predetermined strain is placed on said medical device by abnormal movement of the hip joint caused by the patient.
2. The medical device according to claim 1 , wherein said at least one holding member is spring loaded towards the center axis of the collum femur.
3. The medical device according to claim 2 , wherein said medical device comprises a spring for each at least one holding member causing said spring load on each of the at least one holding member.
4. The medical device according to claim 1 , wherein said at least one holding member is adapted to roll against the caput femur.
5. The medical device according to claim 4 , wherein said at least one holding member comprises a ball shaped part adapted to roll against the caput femur.
6. The medical device according to claim 1 , wherein said medical device comprises a second holding member for restraining said caput femur, or said prosthetic caput femur in said medical device.
7. The medical device according to claim 6 , wherein said medical device comprises a third holding member for restraining said caput femur, or said prosthetic caput femur in said medical device.
8. The medical device according to claim 1 , wherein said holding member comprises a metal material.
9. The medical device according to claim 1 , wherein said holding member comprises a ceramic material.
10. The medical device according to claim 1 , wherein said holding member comprises a polymer material.
11. The medical device according to claim 10 , wherein said holding member comprises HDPE.
12. The medical device according to claim 1 further comprising at least one calibration member for calibrating the pre-determined strain which will release the caput femur or prosthetic caput femur from said medical device.
13. The medical device according to claim 12 , wherein said at least one calibration member is a calibration screw, being rotatable to set said predetermined strain.
14. The medical device according to claim 1 , comprising a plurality of holding members placed in sleeves evenly distributed around the caput femur or a prosthetic replacement therefore.
15. The medical device according to claim 1 , wherein said at least one holding member is a circular elastic band.
16. The medical device according to claim 15 , wherein said medical device further comprises a circular sleeve in which the circular elastic band is slidably arranged.
17. The medical device according to claim 16 , wherein the circular elastic band comprises a weakened portion which may fail upon forces above said predetermined force.