Introduction

Since 1989 we have been using custom lateral-flare stems. Using this stem, its lateral flare can produce high proximal fit and less fit in distal part. Applying this automatic designing software to the average femoral geometries, we can make off the shelf high proximal fit stem (Revelation ®). Putting the off the shelf stem, the original center of the femoral heads were well reproduced. But in DDH cases, severe deformities around hip sometimes make complicated difficulty for better functional reconstruction. They are high hip center such as Crowe II-IV, shortening of the femoral neck, high anteversion etc. DDH cases are well known to have higher anteversion than non DDH cases. There would be no definite explanations for it. The high anteversion would not always be harmful for the preoperative patients. But in some cases, osteophytes are observed at posterior side of the femoral head which make another sphere with different centre. We can guess that the patient's biomechanics had not been matched with the original anteversion. Then posterior osteophytes can correct inappropriate anteversion (self-reduction.) (Fig.1) In those patients, reduction of the anteversion by putting stems twisted into the canal or using modular stems are sometimes done by the surgeons' decision.

Younger DDH cases can also be treated with THA, because of the complicated deformities or biomechanical disorders. Short stems are expected to reduce operative invasion and stress shielding then can reserve bone quality and quantity. From these point of view to improve the understanding of the characteristics of the DDH anteversion, and design a DDH oriented short stem could be one of good solution for those cases.

Background

Cement implantation syndrome characterized by hypotension, hypoxemia, cardiac arrhythmia or arrest has been reported in the literature. The purpose of the present study was to monitor blood pressure soon after cementing.

Purpose

One of the drawbacks of cemented total hip arthroplasty (THA) is aseptic loosening after long period, major reason for which is bioinertness of PMMA bone cement. To improve longevity of THA, interface bioactive bone cement (IBBC) technique which is characterized with smearing hydroxyapatite (HA) granules just before cementation has been used in our institute.

One of the drawbacks of cemented total hip arthroplasty (THA) is aseptic loosening after long period, major reason for which is bioinertness of PMMA bone cement. To improve longevity of THA, interface bio-active bone cement technique combined with modern cementing technique has been used in our institute, and was evaluated clinically and radiologically.

The present study includes 44 cases of primary THA with an average age at operation of 64 years old (ranging 48 to 81). Mean postoperative follow up period was 4 (ranging 3.5 to 5) years.

Pre- and postoperative evaluation using Merle d’Aubigné score were 8.0 and 16.2 points, respectively. Postoperative cementing grade using Barrack’s classification was A or B. At final follow up, radiolucent line at bone-cement interface was not observed, except one case of rheumatoid arthritis patient at zone 3 described by Delee and Charnley in the acetabular side. Neither osteolysis nor loosening was observed in every case. No major complications, such as infection, dislocation, pulmonary embolization, were observed.

The present study revealed excellent short-term result was obtained by IBBC technique combined with modern cementing technique for primary THAs. Most important technical point required for IBBC is to obtain dry bony surface just before cementing. Compressive reamed bone and gauze packing was effective for complete hemostasis just before cementing for the acetabular side, and plugging the isthmus using bone chips was effective for reducing bleeding for the femoral side.