System and method for joint resurface repair

• US 20040015170A1
• Filed: 07/14/2003
• Published: 01/22/2004
• Est. Priority Date: 05/01/2000
• Status: Active Grant

• Current Assignee: Arthrosurface, Inc (Anika Therapeutics Incorporated)
• Original Assignee: Arthrosurface, Inc (Anika Therapeutics Incorporated)
• Inventors: Ek, Steven W., Tallarida, Steven J.
• Granted Patent: US 7,510,558 B2
• Time in Patent Office: Days
• US Class Current: 606/71
• CPC Class Codes: A61B 17/0401 Suture anchors, buttons or pledgets, i.e. means for attaching sutures to bone, cartilage or soft tissue; Instruments for applying or removing suture anchors A61B17/0642 takes precedence; fixation devices for tendons or ligaments A61F2/0811
• CPC Class Codes: A61B 17/0487 Suture clamps, clips or locks, e.g. for replacing suture knots; Instruments for applying or removing suture clamps, clips or locks suture anchors A61B17/0401; wound clamps or clips A61B17/08; ligaturing clamps or clips A61B17/122
• CPC Class Codes: A61B 17/06166 Sutures suture materials A61L17/00; manufacture of artificial threads D01D; treatment of threads D06M
• CPC Class Codes: A61B 17/1615 Drill bits, i.e. rotating tools extending from a handpiece to contact the worked material
• CPC Class Codes: A61B 17/1635 for grafts, harvesting or transplants
• CPC Class Codes: A61B 17/1637 Hollow drills or saws producing a curved cut, e.g. cylindrical A61B10/025, A61B17/1695 take precedence
• CPC Class Codes: A61B 17/1675 for the knee
• CPC Class Codes: A61B 17/1714 for applying tendons or ligaments implements for applying tendons or ligaments A61F2/0805
• CPC Class Codes: A61B 17/1764 for the knee
• CPC Class Codes: A61B 17/7098 wherein the implant is permeable or has openings, e.g. fenestrated screw hollow surgical screws A61B17/864
• CPC Class Codes: A61B 17/8615 at the central region of the screw head
• CPC Class Codes: A61B 17/8625 Shanks, i.e. parts contacting bone tissue
• CPC Class Codes: A61B 17/863 with thread interrupted or changing its form along shank, other than constant taper
• CPC Class Codes: A61B 17/8695 Washers surrounding screw head in plate hole A61B17/8047, between bone plate and bone A61B17/8028
• CPC Class Codes: A61B 17/8805 for introducing fluid filler into bone or extracting it A61B17/7097, A61B17/8833 take precedence
• CPC Class Codes: A61B 17/8827 with filtering, degassing, venting or pressure relief means
• CPC Class Codes: A61B 17/888 the driver bit acting on the central region of the screw head
• CPC Class Codes: A61B 17/8894 holding the implant into or through which the screw is to be inserted A61B17/7082, A61B17/7091 take precedence
• CPC Class Codes: A61B 2017/00238 Type of minimally invasive operation A61B2017/00805 takes precedence
• CPC Class Codes: A61B 2017/00464 for use with different instruments with hole for different instruments A61B2017/22072
• CPC Class Codes: A61B 2017/0404 : Buttons
• CPC Class Codes: A61B 2017/0409 : Instruments for applying suture anchors for applying suture clamps, clips or locks A61B2017/0488
• CPC Class Codes: A61B 2017/044 : with a threaded shaft, e.g. screws
• CPC Class Codes: A61B 2017/0445 : cannulated, e.g. with a longitudinal through-hole for passage of an instrument
• CPC Class Codes: A61B 2017/0448 : Additional elements on or within the anchor
• CPC Class Codes: A61B 2017/045 : snug fit within the anchor
• CPC Class Codes: A61B 2034/108 : Computer aided selection or customisation of medical implants or cutting guides
• CPC Class Codes: A61B 2090/061 : for measuring dimensions, e.g. length
• CPC Class Codes: A61B 5/103 : Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes A61B5/08 takes precedence; measuring aids for tailors A41H1/00; measuring instruments specially adapted for dentistry A61C19/04
• CPC Class Codes: A61B 5/4528 : Joints A61B5/4533, A61B5/4538 take precedence
• CPC Class Codes: A61B 90/06 : Measuring instruments not otherwise provided for
• CPC Class Codes: A61B 90/11 : with guides for needles or instruments, e.g. arcuate slides or ball joints
• CPC Class Codes: A61F 2/30756 : Cartilage endoprostheses A61F2/3603 takes precedence
• CPC Class Codes: A61F 2/30767 : Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/30942 : for designing or making customized prostheses, e.g. using templates, CT or NMR scans, finite-element analysis or CAD-CAM techniques
• CPC Class Codes: A61F 2/38 : for elbows or knees
• CPC Class Codes: A61F 2/3859 : Femoral components
• CPC Class Codes: A61F 2/4603 : for insertion or extraction of endoprosthetic joints or of accessories thereof
• CPC Class Codes: A61F 2/4618 : of cartilage
• CPC Class Codes: A61F 2/4657 : Measuring instruments used for implanting artificial joints for surgical instruments A61B90/06
• CPC Class Codes: A61F 2002/30065 : thermoplastic, i.e. softening or fusing when heated, and hardening and becoming rigid again when cooled
• CPC Class Codes: A61F 2002/30069 : elastomeric
• CPC Class Codes: A61F 2002/30113 : circular
• CPC Class Codes: A61F 2002/30143 : hexagonal
• CPC Class Codes: A61F 2002/30225 : Flat cylinders, i.e. discs
• CPC Class Codes: A61F 2002/30299 : umbrella-shaped or mushroom-shaped
• CPC Class Codes: A61F 2002/30324 : differing in thickness
• CPC Class Codes: A61F 2002/30332 : Conically- or frustoconically-shaped protrusion and recess
• CPC Class Codes: A61F 2002/30354 : Cylindrically-shaped protrusion and recess, e.g. cylinder of circular basis
• CPC Class Codes: A61F 2002/30433 : using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30448 : using adhesives
• CPC Class Codes: A61F 2002/30451 : soldered or brazed or welded
• CPC Class Codes: A61F 2002/30604 : modular
• CPC Class Codes: A61F 2002/30759 : Mosaicplasty, i.e. using a plurality of individual cartilage plugs for filling a substantial cartilage defect
• CPC Class Codes: A61F 2002/30772 : Apertures or holes, e.g. of circular cross section
• CPC Class Codes: A61F 2002/30831 : perpendicular with respect to each other
• CPC Class Codes: A61F 2002/30858 : Threads interrupted by grooves or sidewalls, e.g. flat sidewalls
• CPC Class Codes: A61F 2002/30871 : Trapezoidal threads
• CPC Class Codes: A61F 2002/30873 : Threadings machined on non-cylindrical external surfaces
• CPC Class Codes: A61F 2002/30878 : with non-sharp protrusions, for instance contacting the bone for anchoring, e.g. keels, pegs, pins, posts, shanks, stems, struts
• CPC Class Codes: A61F 2002/30879 : Ribs
• CPC Class Codes: A61F 2002/30892 : parallel
• CPC Class Codes: A61F 2002/30896 : perpendicular with respect to each other
• CPC Class Codes: A61F 2002/30943 : using mathematical models
• CPC Class Codes: A61F 2002/30948 : using computerized tomography, i.e. CT scans
• CPC Class Codes: A61F 2002/30952 : using CAD-CAM techniques or NC-techniques
• CPC Class Codes: A61F 2002/30957 : using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/4635 : using minimally invasive surgery
• CPC Class Codes: A61F 2002/4658 : for measuring dimensions, e.g. length
• CPC Class Codes: A61F 2002/4661 : for measuring thickness
• CPC Class Codes: A61F 2002/4663 : for measuring volumes or other three-dimensional shapes
• CPC Class Codes: A61F 2002/4681 : by applying mechanical shocks, e.g. by hammering
• CPC Class Codes: A61F 2210/0071 : thermoplastic
• CPC Class Codes: A61F 2220/0033 : made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2220/0041 : using additional screws, bolts, dowels or rivets, e.g. connecting screws
• CPC Class Codes: A61F 2220/005 : using adhesives
• CPC Class Codes: A61F 2220/0058 : soldered or brazed or welded
• CPC Class Codes: A61F 2230/0006 : circular
• CPC Class Codes: A61F 2230/0017 : Angular shapes
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2230/0093 : Umbrella-shaped, e.g. mushroom-shaped
• CPC Class Codes: A61F 2250/0036 : differing in thickness
• CPC Class Codes: A61F 2310/00017 : Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00029 : Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
• CPC Class Codes: A61F 2310/00059 : Chromium or Cr-based alloys
• CPC Class Codes: A61F 2310/00089 : Zirconium or Zr-based alloys
• CPC Class Codes: A61F 2310/00095 : Niobium or Nb-based alloys
• CPC Class Codes: A61F 2310/00203 : containing alumina or aluminium oxide
• CPC Class Codes: A61F 2310/00239 : containing zirconia or zirconium oxide ZrO2
• CPC Class Codes: A61F 2310/00796 : Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite

Abstract

A generic bone implant, or set of standardized implants, is created based on using a guide device to develop an axis normal to an articular surface of bone and collecting only one or two data points. A generic cutting tool is used to cut the bone to a point where a generic implant can be used. Several improved tools relating to the procedure for using such an implant, as well as methods for using implants consistent with the invention are further described, including: single-axis and biaxial drill guide tools and methods, generic single-axis implant methods and devices, generic biaxial implant methods and devices, tools and methods for holding or delivering an implant, removal or revision tools and methods, digital measuring systems and methods, and set of measuring gauges for determining the appropriate implant dimensions.

Claims

1. A guide device for locating a working axis substantially normal with respect to an articular surface of bone, said device comprising:

a shaft having an end and an aiming feature for projecting an axis; and

a contact surface comprising a plurality of points radially extending from the aiming feature of said shaft;

wherein said plurality of points of said contact surface surrounds a defect in an articular surface.

2. A guide device as claimed in claim 1, wherein said contact surface is formed by a generally toroidal member coupled to the end of said shaft.

3. A guide device as claimed in claim 1, wherein said contact surface comprises at least one fin, projection, or deformable element.

4. A guide device as claimed in claim 1, wherein said shaft is cannulated, and wherein said guide device is adapted to receive a tool for creating a pilot hole through said cannulated shaft and permit said tool to be driven substantially normal into an articular surface of bone when at least three of said plurality of points of said contact surface make contact with said articular surface of bone.

5. A guide device as claimed in claim 1, wherein said guide device is adapted to receive a guide pin or wire through said aiming feature and permit said guide pin or wire to be driven substantially normal into an articular surface of bone when at least three of said plurality of points of said contact surface make contact with said articular surface of bone.

6. A guide device as claimed in claim 1, wherein said contact surface comprises at least one aperture or transparent portion formed therein, permitting the viewing of at least a portion of an articular surface therethrough.

7. A guide device as claimed in claim 1, wherein said plurality of points of said contact surface corresponds to the plurality of points making contact with an articular surface along the perimeter of an implant.

8. A guide device as claimed in claim 1, wherein said plurality of points of said contact surface corresponds to the plurality of points along the perimeter of a portion of an articular surface to be removed.

9. A guide device for locating a working axis substantially normal with respect to an articular surface of bone, said device comprising:

a shaft having an aiming feature for projecting an axis; and

a contact surface comprising a plurality of points radially equidistant from the aiming feature of said shaft.

10. A guide device for locating a working axis substantially normal with respect to an articular surface of bone, said device comprising:

a shaft having an aiming feature for projecting an axis; and

a contact surface comprising a plurality of points equidistant from the aiming feature of said shaft.

11. A guide device for locating a working axis substantially normal with respect to an articular surface of bone, said device comprising:

a shaft having an end and a central longitudinal axis; and

a contact surface comprising a plurality of points radially equidistant from said central longitudinal axis.

12. A guide device for locating a working axis substantially normal with respect to a non-spherical articular surface of bone, said device comprising:

a first element having a longitudinal axis and a contact surface mounted to a shaft; and

a second element with a contact surface movable with respect to the contact surface of the first element, wherein, when said guide device is placed on a non-spherical articular surface, both contact surfaces make contact with said articular surface.

13. A guide device as claimed in claim 12, wherein each said contact surface comprises a plurality of arcuate sections of a generally toroidal member, wherein said generally toroidal member is formed when said contact surfaces make contact with a locally spherical articular surface.

14. A guide device as claimed in claim 12, wherein one said contact surface is biased in one direction with respect to the other said contact surface.

15. A guide device as claimed in claim 12, wherein said contact surfaces are adapted such that the contact surface of the first element make contact with a plurality of points along either one of the AP or ML curves of an articular surface, while the contact surface of said second element make contact with a plurality of points along the other of the AP or ML curves of said articular surface.

16. A guide device as claimed in claim 12, wherein said first or said second element comprises a cannula, wherein said guide device is adapted to receive a tool for creating a pilot hole through said cannula and permit said tool to be driven substantially normal into an articular surface of bone.

17. A guide device as claimed in claim 12, wherein said first or said second element comprises a cannula, wherein said guide device is adapted to receive a guide pin or wire through said cannula and permit said guide pin or wire to be driven substantially normal into an articular surface of bone.

18. A guide device as claimed in claim 12, wherein said first or said second element comprises at least one aperture or transparent portion formed therein, permitting the viewing of at least a portion of an articular surface therethrough.

19. A guide device as claimed in claim 12, wherein the outermost dimensions of said contact surfaces surround a defect in an articular surface.

20. A guide device as claimed in claim 15, wherein the plurality of points contacting said contact surfaces corresponds to the plurality of points abutting an articular surface along the perimeter of an implant.

21. A guide device as claimed in claim 15, wherein the plurality of points contacting said contact surfaces corresponds to the plurality of points along the perimeter of a portion of an articular surface to be removed.

22. A guide device for locating a working axis substantially normal with respect to an articular surface of bone having an anterior-posterior (AP) curve and a medial-lateral (ML) curve, said device comprising:

a cannulated outer shaft, said outer shaft having a central longitudinal axis and an outer component at its distal end, said outer component comprising a set of arms; and

a cannulated inner shaft slidably disposed within the cannula of said outer shaft, said inner shaft having an inner component at its distal end and sharing the central longitudinal axis of said outer shaft, said inner component comprising a set of arms.

23. A method for replacing a portion of an articular surface of bone, said method comprising:

establishing a working axis substantially normal to an articular surface of bone;

excising only a portion of said articular surface adjacent said axis, thereby creating an implant site; and

installing an artificial implant into said implant site.

24. A method as claimed in claim 23, wherein said implant comprises a bone-facing distal surface adapted to mate with said implant site, said surface comprising at least one mating feature;

and a proximal surface having a contour substantially matching or based on the original surface contour of said excised portion of said articular surface.

25. A method as claimed in claim 24, wherein said mating feature is selected from the group consisting of:

barbs, threads, ribs, fins, milled slots, tapered distal features, features to prevent rotational movement of said implant, or features to increase friction and/or contact surface between said implant and the aperture at said implant site.

26. A method for replacing a portion of an articular surface of bone, said method comprising:

establishing a working axis substantially normal to an articular surface of bone;

excising only a portion of said articular surface adjacent said axis, thereby creating an implant site;

selecting an implant corresponding to the dimensions of said implant site from a set of variously-sized implants; and

installing said selected implant into said implant site.

27. A method as claimed in claim 26, wherein said establishing step is performed using a tool comprising a shaft having an aiming feature and a distal surface comprising a plurality of points radially extending from said aiming feature.

28. A method as claimed in claim 26, wherein said implant comprises a bone-facing distal surface adapted to mate with said implant site, said surface comprising at least one mating feature;

and a proximal surface having a contour substantially matching or based on the original surface contour of said excised portion of said articular surface.

29. A method as claimed in claim 28, wherein said mating feature is at least one of the features selected from the group comprising:

barbs, threads, ribs, fins, milled slots, tapered distal features, features to prevent rotational movement of said implant, or features to increase friction between said implant- and the aperture at said implant site.

30. A method as claimed in claim 26, wherein said establishing step is performed using a tool comprising a shaft having an end and an aiming feature;

and at least one contact surface coupled to the end of said shaft, said contact surface comprising a plurality of points radially extending from said aiming feature.

31. A method as claimed in claim 26, wherein said establishing step is performed by installing a guide pin or wire into said articular surface along said axis.

32. A method as claimed in claim 26, wherein said excising step is performed using a cutting tool that rotates about said axis.

33. A method as claimed in claim 26, wherein said installing step comprises driving a fixation element into said articular surface along said axis.

34. A method as claimed in claim 33, wherein said fixation element comprises a mating feature at its proximal end.

35. A method as claimed in claim 33, wherein said fixation element comprises a screw.

36. A method as claimed in claim 34, wherein said fixation element is adapted to mate, position, or align with an element adapted to aid in the depthwise positioning of said fixation element with respect to said articular surface.

37. A method as claimed in claim 34, wherein said mating feature is adapted to mate, position, or align with the distal portion of an implant.

38. A method as claimed in claim 37, wherein said mating feature is adapted to prevent movement of said implant with respect to said fixation element.

39. A method as claimed in claim 33, wherein said fixation element comprises a tapered distal feature and/or aggressive distal threads.

40. A method for replacing a portion of an articular surface of bone generally defined by a first and a second curve, said method comprising:

establishing an axis generally normal to the portion of an articular surface of bone to be replaced based on a first curve and a second curve of said articular surface;

excising only a portion of said articular surface adjacent said axis, thereby creating an implant site;

fabricating an artificial implant corresponding to the dimensions of said implant site; and

installing said artificial implant into said implant site.

41. A method as claimed in claim 40, wherein said implant comprises a bone-facing distal surface adapted to mate with said implant site, said surface comprising at least one mating feature;

and a proximal surface having a contour substantially matching or based on the original surface contour of said excised portion of said articular surface.

42. A method as claimed in claim 41, wherein said mating feature is selected from the group consisting of:

barbs, threads, ribs, fins, milled slots, tapered distal features, features to prevent rotational movement of said implant, or features to increase friction between said implant and the aperture at said implant site.

43. A method for replacing a portion of an articular surface of bone generally defined by a first and a second curve, said method comprising:

establishing an axis generally normal to the portion of an articular surface of bone to be replaced based on a first curve and a second curve of said articular surface;

excising only a portion of said articular surface adjacent said axis, thereby creating an implant site;

selecting from a set of variously-sized artificial implants an artificial implant corresponding to the dimensions of said implant site; and

installing said selected implant into said implant site.

44. A method as claimed in claim 43, wherein said first and second curves are anterior-posterior (AP) and medial-lateral (ML) curves.

45. A method as claimed in claim 43, wherein said excising step is performed by cutting at least a portion of said articular surface radially symmetrically about said axis.

46. A method as claimed in claim 43, wherein said implant comprises a bone-facing distal surface adapted to mate with said implant site, said surface comprising at least one mating feature;

and a proximal surface having a contour substantially matching or based on the original surface contour of said excised portion of said articular surface.

47. A method as claimed in claim 46, wherein said mating feature is selected from the group consisting of:

barbs, threads, ribs, fins, milled slots, tapered distal features, features to prevent rotational movement of said implant, or features to increase friction between said implant and the aperture at said implant site.

48. A method as claimed in claim 43, wherein said establishing step is performed using a tool comprising a first element having an aiming feature and a contact surface mounted to a shaft, and a second element with a contact surface movable with respect to the contact surface of the first element, wherein, when said tool is placed on a non-spherical articular surface, both contact surfaces make contact with said articular surface.

49. A method as claimed in claim 43, wherein said establishing step is performed by installing a guide pin or wire into said articular surface along said axis.

50. A method as claimed in claim 43, wherein said excising step is performed using a cutting tool that rotates about said axis.

51. A method as claimed in claim 43, wherein said installing step comprises driving a fixation element into said articular surface along said axis.

52. A method as claimed in claim 51, wherein said fixation element comprises a mating feature at its proximal end.

53. A method as claimed in claim 51, wherein said fixation element comprises a screw.

54. A method as claimed in claim 52, wherein said mating feature is adapted to mate, position, or align with an element adapted to aid in the depthwise positioning of said fixation element with respect to said articular surface.

55. A method as claimed in claim 52, wherein said mating feature is adapted to mate with the distal portion of an implant.

56. A method as claimed in claim 55, wherein said mating feature is adapted to prevent movement of said implant with respect to said fixation element.

57. A method as claimed in claim 51, wherein said fixation element comprises a tapered distal feature and/or aggressive distal threads.

58. A tool for holding an implant, said tool comprising:

at least one element adapted for connection to an activatable suction source; and

an elastomeric suction tip adapted to receive an implant, said tip being coupled to said at least one element.

59. A tool as claimed in claim 58, further comprising a rigid tip disposed within the elastomeric suction tip, whereby a force in the direction of the delivery site of said implant permits said rigid tip to contact said implant while said implant is being held by said suction tip.

60. A method for holding an implant comprising:

coupling a suction source to an implant; and

activating said suction source.

61. A method for delivering an implant comprising:

coupling an active suction source to an implant;

approximating said implant to its delivery site; and

applying a force to said implant in the direction of said delivery site.

62. A tool for removing an implant from its delivery site, said tool comprising:

an element with a generally leading edge and a barb element disposed proximally to the leading edge; and

at least one structural element that creates sufficient bias of the leading edge of the tool to rigidly couple to a surface of the implant to be removed.

63. A tool as claimed in claim 62, further comprising means for coupling said tool to a slap hammer or slide hammer capable of applying a pulling force to an implant held at said barb element.

64. A tool for removing an implant from its delivery site, said tool comprising:

a cylindrical structure having an end;

said end comprising a longitudinal central axis, a circular blade portion having a leading edge comprising a blade surface turned on the distal-most portion, and a lip portion disposed proximally with respect to the leading edge; and

a plurality of slits parallel to the longitudinal central axis of said end formed along the length of said cylindrical structure, so as to permit sufficient outward expansion of the distal end to accommodate the top edge of an implant therein.

65. A tool as claimed in claim 64, further comprising means for coupling said tool to a slap hammer or slide hammer capable of applying a pulling force to an implant held in said distal end.

66. A method for removing an implant from its delivery site, said method comprising:

disposing the lip portion of the leading edge of the end of a removal tool over the upper edge of an implant seated in its delivery site; and

applying a pulling force to said removal tool.

67. A method as claimed in claim 66, wherein said pulling force is applied using a slap hammer or slide hammer.

68. A device for measuring a portion of an articular surface of bone, said device comprising:

a handpiece;

a shaft disposed within said handpiece, said shaft comprising a feature for aligning with a working axis or mating to a fixed element;

a contact tip moveably coupled to said shaft; and

at least one measuring element coupled to said contact tip or said shaft.

69. A device as claimed in claim 68, further comprising recording means for recording measurements taken by said at least one measuring element.

70. A device as claimed in claim 69, wherein translation and/or rotation of the contact tip with respect to the handpiece or shaft causes said at least one measuring element to measure travel of the contact tip, and the recording means to record at least one measurement taken by at least one said measuring element.

71. A device as claimed in claim 70, further comprising machine-readable code to analyze said at least one recorded measurement and output to a user the dimensions of an implant to be used in said articular surface.

72. A device as claimed in claim 70, further comprising machine-readable code to analyze said at least one recorded measurement and compare said measurement to at least one previously taken measurement.

73. A device as claimed in claim 70, further comprising machine-readable code to analyze said at least one recorded measurement, select an implant corresponding to said at least one measurement from a set of variously-sized implants, and output to a user said selection.

74. A device for mapping a portion of an articular surface of bone, said device comprising:

a handpiece;

an inner shaft running along the length of and disposed within said handpiece, said inner shaft comprising a mating feature for mating with a fixed element located substantially normal with respect to an articular surface;

a contact tip slidably and rotatably disposed about said inner shaft;

a rotary measuring element coupled to and rotating with said contact tip; and

a linear measuring element nested concentrically and coaxially to said rotary measuring element, and coupled to and moving linearly with said contact tip.

75. A device as claimed in claim 74, further comprising recording means for recording measurements taken by said measuring elements.

76. A device as claimed in claim 75, wherein translation and/or rotation of the contact tip with respect to the handpiece or shaft causes said measuring elements to measure travel of the contact tip, and the recording means records measurements taken by the measuring elements simultaneously, when the mating feature of said inner shaft is mated with said fixed element and/or said contact tip is fixably aligned to a working axis.

77. A device as claimed in claim 76, further comprising machine-readable code to analyze said recorded measurements and output to a user the dimensions of an implant to be used in said articular surface.

78. A device as claimed in claim 76, further comprising machine-readable code to analyze said recorded measurements, select an implant corresponding to said measurements from a set of variously-sized implants, and output to a user said selection.

79. A set of guide devices for locating a working axis substantially normal with respect to an articular surface of bone or for determining the dimension of an implant to be installed in an articular surface of bone, said set comprising:

a plurality of variously dimensioned guide devices, each said guide device having a handling tab or shaft and a contact surface;

said contact surface comprising a plurality of points radially extending from said handling tab or shaft;

wherein, when at least one said guide device is placed on an articular surface, said contact surface makes contact with said articular surface, and said plurality of points of said contact surface surrounds a defect in said articular surface.

80. A set of guide devices as claimed in claim 79, wherein said plurality of points of at least one said guide device do not all lie in the same plane.