We recently shared a series of updates on LinkedIn following a complex total hip arthroplasty (THA) revision case performed by Dr Rehbein of St. Josef's Hospital Wiesbaden, Germany in December . Today, we’re happy to report the patient is recovering well with their patient-specific hip replacement. This blog will highlight the step-by-step process towards the surgery and follow-up and understand why this solution was chosen, more details on how the process works and finally treatment outcomes.
In late October last year, Dr Rehbein contacted our team at Corin about one of his patients who required surgery for a loosened acetabular revision cup.
The failure was causing severe pain (VAS pain score = 8-9) and limiting mobility, meaning the patient could only walk short distances aided by double crutches. With ‘off the shelf’ solutions restricting his treatment options, Dr Rehbein turned to a custom solution looking to achieve excellent implant stability as well as restore and improve the patient’s biomechanics.
Starting the design
We brought in OSSIS, who collected the preliminary case information, including CT and X-ray data, and prepared an initial design for virtual review on 1 November.
In just one hour, the group managed to discuss in detail the initial designs, collect more clinical needs and cover any questions either side had. Managing the review in this way was flexible, inclusive and means design ideas can be shared and discussed easily in real time.
The following day, a full design was sent to Dr Rehbein for his final review.
The final design
Following analysis of the patient data, a patient-specific surgical plan was created. This plan aimed to align the operative cup centre with the contralateral side, achieve good initial implant stability with a custom screw plan and define areas of bone which would be removed to fit the implant successfully.
Flanges and hooks were designed to fit closely to bony landmarks and provide passive stability to the implant, while different porous structures were applied to certain areas. The augmented section, to fill the cup void, used a mechanically optimised cubic lattice structure to reduce implant mass and stiffness and bony interfaces used a bone mimicking, highly porous structure to encourage bone ingrowth and long-term stability.
From ‘data’ to ‘delivered’ in just 6 weeks
Once approved by Dr Rehbein, the design files were sent for manufacture. These custom implants are made in Titanium (Ti6Al4V) alloy by additive manufacturing (or 3D printing), in order to allow the complex, single body shapes.
The implant was manufactured, inspected, packaged, and shipped along with accompanying models and guides, to Germany by 1 December… two weeks prior to surgery, leaving plenty of time for Dr Rehbein to prepare for the case.
Successful surgery and great follow up
Surgery took place on 15 December and was incredibly successful.
“The shape of the lateral flange fitted very precisely to the ileum bone and provided excellent stability. Importantly, the centre of rotation was reconstructed perfectly with equal leg length and good offset, while the cup inclination and version was exactly as planned”, said Dr Rehbein.
At seven weeks follow-up, the patient was walking 800m or more without the use of double crutches and their VAS pain score had reduced from 8-9 to 0. The patient is very well and now living pain free.
Corin Hip Team