Revision hip surgery is increasing each year. We describe a case of revision hip surgery of a fully ingrown modular stem in which the supplied manufactures replacement modular head did not fit the original taper. This resulted from a change in the manufacturing process and taper dimensions between the primary index hip replacement and the revision operation. The manufacturing company was not aware of this change in their manufacturing process. This caused problems during surgery.

A thirty-nine year old male patient had a Mittel-meier uncemented hip prosthesis performed for avascular necrosis of the femoral head in 1988. Twelve years following the index primary hip replacement the cup was loose and migrating so revision of the acetabular component was planned.

A selection of Mittelmeier heads was obtained from the company. The ceramic head was removed and the acetabular component revised for a cemented cup. It was then discovered, during the operation, that the supplied heads did not fit the taper on the stem. The manufacturers had changed the dimensions of the taper since the original prosthesis had been implanted in 1988. Several companies had marketed this prosthesis since 1988 and the current supplier was unaware of a change in the taper. With the cup already cemented in place there were limited options. By chance the Exeter heads fitted the taper on the femoral component and were used. The patient recovered uneventfully.

The Mittlemier is not the only prosthesis to change its taper during its lifetime. If as in this case the manufacturers are unaware of a change in the manufacturing process the surgeon has no way of confirming the information provided prior to the surgery. This case highlights the potential problems when trying to partially revise a modular component.

Autologous drains are used frequently in total knee replacement surgery but not in total hip replacement surgery (THR). Previous studies have shown that these drains are not cost effective in THR surgery. We studied the effectiveness of autologous drains in THR surgery compared with normal suction drains.

All the patients had an uncemented hip. The Bellovac®A.B.T (Astra) autologous drainage system was used. Patients using the drains were studied prospectively and the volume of drainage, volume of autotransfusion, amount of homologous blood transfused and the hospital stay were all recorded. A group of patients who had normal suction drains were studied retrospectively to determine the transfusion rate and hospital stay using these drains.

In the group using standard suction drains there were 43 patients with a mean age of 72. The mean drainage was 641 ml (Range 500 – 1070). 10 patients out of 43 had a transfusion (Transfusion rate 23%). A total of 21 units of blood were used. The mean hospital stay was 14 nights. In the group using autologous drains there were 38 patients with a mean age of 67. The mean drainage was 703 ml (Range 200 – 1700), and of this the mean volume of blood that was given back to the patient was 445 ml (Range 50 – 1050). 2 out of 38 patients have required a blood transfusion, a transfusion rate of 5 % . This reduction in transfusion rate is significant (p< 0.005). The mean hospital stay was 9 nights. The difference in the hospital stay was not statistically significant.

Using the autologous drainage system in uncemented total hip replacement surgery reduces the need for a homologous blood transfusion. It is simple and easy to use and avoids the complications of a blood transfusion. It was also found to be cost effective.