Finger joint prosthesis made of metal

A finger joint prosthesis comprising:

• a metacarpal implant including a first stem adapted to be inserted in a cavity formed in a metacarpal bone and carrying a bearing shaft having an axis oriented transversely to the stem;
• and
• a phalange implant including a second stem adapted to be inserted in a cavity formed in a phalange bone and carrying, on an end of the stem, a generally C-shaped bearing housing adapted to fit over and pivotally engage the bearing shaft and defining edges oriented parallel to the bearing shaft, the phalangeal implant including a slit extending from the bearing housing over a substantial portion of the length of the second shaft dividing the phalangeal implant into first and second, opposing halves;
• whereby the implants can be assembled by temporarily spreading apart the first and second halves of the phalangeal implant and then moving the bearing shaft past the edges in a radial direction into the C-shaped housing and thereafter releasing the halves to fully seat the shaft in the housing;
• and
• whereby the edges of the C-shaped housing engage the first stem during relative pivotal movements of the implants and thereby limit an angle over which the implants can be pivoted with respect to each other.

A finger joint prosthesis comprising:

• a first part for implantation in a cavity of a metacarpal bone including a first stem for insertion in the metacarpal cavity, a bearing shaft, and means connecting the shaft to the first stem;
• a second part for implantation in a cavity in a phalange bone including a bearing housing having a concavely shaped bearing surface for pivotally engaging the shaft, the housing extending over an arc of less than 360.degree. to define an open area bounded by first and second edges of the housing extending along the shaft, a second stem attached to the housing, extending transversely away from the housing, ending in a free end and adapted to be inserted in the phalange bone cavity, the second part including a slit extending from the bearing surface of the housing towards the free end of the second stem to define opposing portions of the second part separated by the slit, the slit having a sufficient length to permit spreading of the first and second portions and therewith of the bearing housing edges from a closed position away from each other to enable an insertion of the bearing shaft past the housing edges while said housing edges are spread apart;
• and
• means for thereafter returning the first and second portions to and maintaining said portions in the closed position so that, thereafter, the shaft and the housing pivotally engage each other.