The TriFit hip replacement platform, integrated with OPSInsight™, the smart way to operate! – a case review

Designed for patient fit


The TriFit hip replacement platform is designed to provide flexibility for surgeons to perform total hip arthroplasty through their preferred approach, while choosing the stem that best fits patient anatomy. TriFit TS, a unique tapered wedge stem and TriFit CF, a “fit-and-fill” stem, incorporate the following features:



                         Fig. 1: TriFit hip replacement platform


The flexibility provided with TriFit, when combined with Corin’s OPSInsight preoperative planning system, helps surgeons evaluate the patient’s unique joint biomechanics to plan and execute an optimised total hip arthroplasty.

One unique feature of the customized OPSInsight report is the radiodensity analysis. This feature provides a colour map that helps to visualise the radiodensity of the bone at the intersection of the surface of the templated implants based on the intensity of Hounsfield Units (HFU) values from the CT DICOM. The scale represented in the colour map is linear between blue and red as follows:


Fig 2. Radiodensity scale (Housefield Units)            

Fig. 2: Radiodensity scale (Hounsfield Units)



Fig. 3: TriFit TS radiodensity pattern using OPSInsight (left hip).


TriFit TS has an optimised proximal-to-distal ratio and proximal flare that aim to promote stability. The stem is designed to fill the largest M-L dimension of the femoral canal.

Fig. 3 shows a templated TriFit TS stem. The radiodensity tool shows areas of cortical contact in the calcar region (red area) and contact with medium density bone in the metaphysis (green). The stem is planned to avoid distal cortical contact in the diaphysis, which can be linked to thigh pain.


Fig. 4: TriFit CF radiodensity pattern using OPSInsight (left hip): left, anterior view; right, lateral view.


TriFit CF is a “fit and fill” stem. This stem philosophy aims to fill the femoral canal to achieve fixation. In the anterior view of the radiodensity analysis we can see how the stem has contact with medium density bone (green) throughout the canal, with different areas of contact with high density bone (red). We do not see large blue areas throughout the femoral canal, which could be an indication of under-sizing.

For this specific patient the surgeon decided to select a TriFit CF stem as the patient had a Dorr type C or pipe type femur. In the preop AP X-ray, we see the thin cortical bone and a wide femoral canal. In this situation, the surgeon templated TriFit TS and TriFit CF using OPSInsight, and compared the radiodensity patterns with both stems (Fig. 3 and Fig. 4). Based on the surgeon’s clinical knowledge, TriFit CF was the preferred option for this specific patient. The surgeon used the radiodensity pattern as part of the information available to guide his clinical decision. The surgeon felt that for this case he could achieve better stability and recreate the patient’s biomechanics using TriFit CF.


Fig. 5: Preoperative AP X-ray in a patient suffering from osteoarthritis (OA) of the right hip shown in OPSInsight.


Fig. 6: Postoperative AP X-ray showing the implanted TriFit CF and Trinity cup.


In these two images we can compare the preoperative X-ray showing the OA suffered by the patient in the right hip (Fig. 5) and the postoperative X-ray for the patient after using OPSInsight as a preoperative and intraoperative tool, with TriFit CF and Trinity.

The TriFit platform offers different options to adapt to each individual patient’s needs and OPSInsight provides powerful insights to drive better outcomes. In combination, both systems offer the surgeon versatility to provide the best solution for each patient.


Corin Hip Team.