Minimally invasive approaches to the hip may be divided into two categories: single mini-incisions derived from standard approaches and two-incision approaches designed specifically for minimally invasive total hip replacement. The authors have a number of specific concerns about the latter based on its apparent transgression of basic surgical principles and favour a mini-lateral approach to the hip which they describe and review.

The two-incision approach requires two short (2–5cm) incisions from two different directions. Unlike other minimally invasive techniques, these incisions run close to the major neurovascular structures, which have been damaged. Visibility is limited as demonstrated by the need for navigation systems and illuminated retractors by some groups. Accurate resection of the femoral neck is obscured by the presence of the femoral head. Precise siting of the socket may be compromised by poor visibility. Most series accomodate only the use of uncemented components. Claims for more rapid mobilisation appear to depend more on anaesthetic rather than surgical technique.

We have developed the mini-lateral approach to the hip, in parallel with others, over the last five years. It is a scaled-down version (< 10cm) of the Hardinge approach which has been used successfully for 25 years. It relies on a precise appreciation of the regional anatomy requires no additional equipment and avoids the problems posed by the two-incision approach. A short video presentation will be given.

We present a consecutive retrospective series of 99 patients having 103 cemented C-stem THA for OA over a three-year period. Patients were assessed for duration of surgery, blood loss and length of postoperative stay. At follow-up (mean 18/12) they were assessed using the Oxford Hip Score, radiographic analysis and their incisions were measured. No hips have been revised and none are considered to be at risk. No nerve or vascular injuries have been reported.

Aims: To assess the failure rate at 5 years of the Elite Plus (DePuy) femoral stem and identify reasons for early failure. Particular attention was paid to the quality of the cement mantle.

Methods: A cohort of the first 241 primary THR performed in 234 patients were identified. Each patient completed the Oxford Hip Score (OHS), and had AP and lateral radiographs. The cement mantle was graded by Mulroy’s modification of Barrack’s system using all AP and lateral radiographs.

Results: At follow up 39 patients (42 hips) had died, 14 were lost to follow up and 35 (36 hips) too unwell/ unwilling to take part leaving149 hips in 146 patients available for independent assessment. The mean follow up was 60.2 months (range 48.3–75.8 months). Five hips (3.4%), have been revised, 1 after traumatic dislocation, 1 for deep infection and 3 for aseptic loosening. In a further 11 (7.4%) patients there was radiological evidence of progressive femoral loosening, although only 2 of the 7 available for review were symptomatic. The median OHS was 20 (range 12–51). All those revised or radiologically loose had defective cement mantles (C2). A cement mantle less than 1 mm thick was associated with early failure (p< 0.03).

Conclusions: The revision rate at 5 years is 3.4%. Loosening is related to suboptimal cement mantles in particular mantle thickness of less than 1 mm. We have documented the invisible cohort of those who have loosened radiologically but are asymptomatic. Regular surveillance of this cohort is mandatory to allow comparison with longer-term results of other prostheses.

It is well known that the integrity of the bone cement interface is crucial for the long-term survival of a primary total hip arthroplasty (THR). Revision THR with impaction bone grafting has recently offered a solution to gross bone loss due to osteolysis. As graft becomes incorporated, clearly the bone graft/cement interface is as crucial as the equivalent interface in primary THR.

The aim of this study was to examine factors that influence this interface. The effects of bone particle size, cement mixing time, and impaction force were examined.

The study was designed to mimic clinical practice. Fresh femoral heads were harvested from primary THR. These were morcelised into large and small particles. The bone was impacted into a purpose built jig with measured force. Cement was pressurised onto the dried surface of the impacted bone after measured mixing times. Cement pressurisation was measured. The cement/graft specimen was extracted and transected with a band saw. Cement penetration was measured with digital image analysis.

Large fragment size was 29 mm², and small was 7. 1mm². Light impaction was 2. 2 Atm. Medium and heavy were 2. 6 Atm. and 3. 2 Atm. respectively. Cement penetration was inversely proportional to impaction force. Cement mixing time also significantly affected cement penetration. Particle size had no effect.

Allograft should be adequately but not excessively impacted, to allow good cement incursion. Cement should be introduced and pressurised perhaps as early as two minutes. Fragment size does not affect cement penetration.