Catalogue No. 1 One of the first prototypes of an acrylic femoral hemiarthroplasty, intended for fixation by means of a nut-and-bolt system

Catalogue No. 2 The first acrylic implant. First inserted in 1946. Implanted only in the femoral neck, by means of a stem. Anterior approach to the hip joint, resection of head, followed by shaping of the neck with a hand tool to fit the implant base. The tip of the stem might protrude from the femoral shaft cortex. First complications were subsidence and protrusion of the tip below the trochanter, and stem breakage.

Catalogue No. 3 Acrylic hemiarthroplasty with metal-reinforced stem. Subsidence was still a problem; the implant might also go into varus.

Catalogue No. 4 Acrylic implant with slanting head base, designed to resist movement into varus. First problems with acrylic head wear.

Catalogue No. 5 Metal implant with slanting base, 1952. Metal (stainless steel, later 'neutralium') was chosen to control the problem of wear. The slanting base prevents shear stress. Fixation still confined to the epiphysis. Acetabular wear is becoming a problem.

Catalogue No. 6 'Parachute" prosthesis. Attempt to protect the acetabulum by interposing a sheet of nylon fabric or skin over the femoral head.

Catalogue No. 7 The 'jockey cap', 1953. Teflon acetabular cup, with a tab fixed to the acetabular rim by means of a screw.

Catalogue No. 8 Oblique-head hemiarthroplasty. Implant supported by the head, and in the neck and shaft. Introduced after the Austin-Moore device. Intended to replace only the upper portion of the femoral head, in cases of OA and of necrosis.

Catalogue No. 9 Total-head hemiarthroplasty. Intended to replace the femoral head and the entire femoral neck, especially in the management of fractures. Differs from the Austin-Moore in that it has a thinner stem, and an anti-rotation wing. Unusual seating pattern in the femoral neck ('egg in an egg-cup').

Tableau 10 Total hip replacement, with short stem. Designed to transmit stresses to the trochanter only. First consideration of how to prevent stress shielding. The cup is snap-fitted onto the stem, and held by a detachable ring to prevent displacement during cementing. This design was required by the technique used for implant insertion: Anterior approach, on an orthopaedic table. Preparation of the acetabulum and the femur. Cementing of stem. Introduction of cement into the acetabulum, followed by reduction of the femoral component complete with snap-on cup into the acetabulum. Ring prevents tilting of cup during cementing. After curing of the cement, the ring is removed.

Catalogue No. 11 Long-stem THR, designed to cope with the frequent migration into varus of the stems previously used.

Catalogue No. 12 The Tory-Bloc prosthesis. Unlike the others in this collection, this is a trunnion-type prosthesis, with an additional joint between the head and the neck. Early failures due to wear and trunnion breakage.

Catalogue No. 13 Cementless THR. First implanted in 1971. Cast in a stellite alloy; two original features: biological fixation as a result of bone ingrowth into a porous surface ('porometal'); and a morse taper, as a first step on the road to modular implants. Cylindrical socket, as a compromise between the requirement for primary stability and machining constraints. Stabilizers on the femoral component: an anti-rotation wing, taken over from the total-head hemiarthroplasty; a collar; and a square-section stem.

Catalogue No. 14 'Saturn ring' cementless socket, designed for implantation into the iliac wing in cases of high CDH with OA.

Catalogue No. 15 Further development of cementless socket (1978). Improvement of primary stability by use of screws in addition to press-fit. Interchangeable PE insert.

Screw-fixed cementless socket at 13 years: Note elastic bands used to manage an intraoperative shaft fracture.