Reaming
The acetabulum is reamed such that the sub-chondral bone is retained to seat the cup. To ensure good biological fixation, the cup must be implanted in sub-chondral, bleeding bone. For the first reaming, the smallest reamer is applied, reaming straight down without any angulation (Fig. 9)

Successive reamers, which increase in size by 2mm increments, are used approaching the acetabulum at a 40° - 45° angle with the required anteversion. Ream until the trial cup is stable and sufficiently covered by the bone of the acetabulum. When using the final reamer, do not use excessive rotational movement to avoid oversizing the cavity (Figs. 10 & 11).

Insertion of thetrial cup
A trial cup of the same diameter as that of the definitive implant (exact fit) is impacted into the acetabulum, matching the anteversion and the inclination of the reamer (Fig. 12). The trial cup must be completely stable in the acetabulum. The holes in the trial cup allow verification of intimate contact between the implant and the host bone. The diameter of the trial cup is identical to that of the definitive implant. If the trial cup is unstable, a check should be made to see if there is capsular or other soft tissue protruding beyond the periphery and interfering with cup impaction. Instability may, however, be due to insufficient reaming; in such cases, stability will be improved by some slight additional reaming of the acetabulum, using a reamer 2 - 4mm smaller than the size of the trial cup. Following this, another stability check must be made. The trial cup is removed. Any subchondral bone cysts are opened, curetted, and packed with cancellous bone obtained from the femoral head.

Fig. 12 Insertion of the trial cup to check stability and identify final cup size.

Insertion of the ABG™II no-hole cup
Fixation of spikes
This is the preferred cup for use in primary hip replacement. After opening the inner packaging, the cup is mounted on the cup holder. Two 8mm spikes are normally used.* The spikes must be screwed in with the “spikedriver”, to occupy two adjacent holes in the row of holes nearest the pole of the cup. The spikes must be screwed flush as firmly as possible (Fig. 13).
*Bone quality permitting, a single spike may be used.

Insertion of no-hole cup
The cup is mounted on the cup impactor, and the cup holder is removed. The cup is impacted into the acetabulum, at 45° inclination and approximately 15° anteversion. The cup is inserted with the spikes positioned superiorly at 11 o’clock and 1 o’clock (Fig. 14).

The cup is then tapped in with a mallet until it is correctly positioned in the acetabulum (the inferior margin of the metal cup should be level with the upper border of the obturator foramen). A check is made for cup stability. If stability is found to be insufficient, the cup is removed, to check for capsular or other softtissue interposition. Sometimes, stability may be improved by the addition of a third 8mm spike, in a triangular pattern; this spike should be screwed into the row of holes nearest the cup equator. The metal cup is re-inserted, and another check is made for stability. The cup impactor is removed, and a trial insert is placed in the cup.

Fig. 13 Spikes can be used with the No-Hole Cup for additional rotational stability.

Fig. 14 The cup is implanted with the spikes positioned superiorly.

Insertion of the ABG™II 5-hole cup
Spike fixation
This cup is used in primary hip arthroplasty; however, it is mainly intended for revision surgery.
After opening the inner packaging, the cup is mounted on the cup holder.
Two 7mm or 9mm spikes are normally used. The spikes must be screwed into the inside of the cup with the hexagonal screwdriver, to occupy two adjacent holes in the row of holes nearest the pole of the cup. The spikes must be screwed flush as firmly as possible (Fig. 15).
The cup is mounted on the cup impactor, and the cup holder is removed (Fig. 16). The cup is impacted into the acetabulum, at 45° inclination and approximately 15° anteversion. The cup is inserted with the spikes positioned superiorly at 11 o’clock and 1 o’clock.

The cup is then tapped in with a mallet until it is correctly positioned in the acetabulum (the inferior margin of the metal cup should be level with the upper border of the obturator foramen).
A check is made for cup stability, and the cup impactor is removed.

If stability is found to be insufficient, a check should be made for capsular or other soft-tissue interposition.

Obturator screws
The ABG™II obturator screw can be used to seal any vacant holes in the 5-Hole cup. The obturator screw provides a water-tight seal to reduce the risk of particulate debris migration. Ensure that the obturator is firmly screwed into position with the hexagonal socket screwdriver and sits flush.

Insertion of cancellous screws
In some cases of cup instability, or in revision surgery, the spikes may be replaced by 6mm cancellous screws. A drill guide is provided for this purpose. The end of the guide can be screwed into the intended hole in the cup, using the hexagonal socket screwdriver. A drill bit of the required length is introduced into the guide, to drill the cancellous bone. The drill guide is removed. The screw length gauge allows the screw length to be determined; the screw itself is inserted with the hexagonal socket screwdriver. In order to prevent impingement, it is important to ensure that the screw, which is held in the cup with its double thread, is fully recessed in the cup. For cup fixation, one screw or several screws may be used.

Next, the trial insert is placed in the cup.

Fig. 15 Fixation of spikes to the                                Fig. 16 Fixation of the cup
5-hole cup implant (if required).                                to the impactor.