Artificial intelligence can help doctors better predict how well patients with hip osteoarthritis will recover after hip surgery. Researchers at the Karlsruhe Institute of Technology (KIT) have developed an AI model that analyses movement patterns and, based on this, provides insight into the expected walking ability after a total hip replacement. The approach also makes it possible to better tailor rehabilitation programmes to individual patients.
Total hip replacement is one of the most commonly performed orthopaedic procedures. In Germany alone, approximately 220,000 people receive an artificial hip each year, usually due to hip osteoarthritis resulting from wear and tear of the cartilage in the femoral head and acetabulum. Although the operation often leads to pain reduction and improved mobility, recovery varies greatly from patient to patient. Some people walk almost normally afterwards, while others continue to experience limitations.
Movement data as the key
Understanding these differences is central to a joint research project between Universitätsmedizin Frankfurt and the Institute of Sports and Sports Science at KIT. In the project, which is supported by the German research funding organisation DFG, researchers are combining clinical data with advanced data analysis.
The basis for the AI model consists of so-called gait biomechanics data: detailed measurements of walking movements before and after surgery. This data, collected and processed in Frankfurt, was used by KIT to recognise and classify patterns in patients' walking patterns.
‘The biomechanical data describing human movement are extremely complex,’ says Bernd J. Stetter, researcher at KIT and corresponding author of the study. ‘With our AI model, we make this data applicable in clinical practice. This is an important step towards personalised care.’
Three recovery profiles
For the study, published in Arthritis Research & Therapy, the researchers analysed the walking movements of 109 patients with unilateral hip osteoarthritis before surgery. Measurements were also taken again after the operation from 63 of them. In addition, 56 healthy individuals served as a control group. Joint angles and loads were calculated using three-dimensional motion models.
The AI analysis distinguished three groups of patients with clearly different patterns of change in their gait. Certain parameters, such as hip angle and joint load, proved crucial in classifying patients. The groups differed not only biomechanically, but also in age, physique, walking speed and severity of osteoarthritis.
After the operation, the groups responded differently. In some patients, the gait pattern improved significantly and approached that of the healthy control group. In others, clear abnormalities remained.
Prediction model
According to Stetter, the model makes it possible to better predict in advance who will benefit greatly from hip surgery and who will need extra intensive care afterwards. ‘Our model can predict which patients will recover particularly well and which will need additional therapy,’ he says. ‘Because the algorithms are explainable and transparent, we expect a high degree of clinical acceptance.’
Although the model has now been developed for the hip, the researchers see opportunities to extend the approach to other joints and conditions in the future. This research shows how AI and biomechanics can work together to contribute to more realistic expectations, better decision-making and more personalised rehabilitation in orthopaedic care.
3D-printed hip
A few weeks ago, the Dutch Anna Hospital performed the world's first implantation of a custom-made, 3D-printed hip implant in a human being. The procedure, performed by orthopaedic surgeon Rintje Agricola in collaboration with the LUMC, marks an important innovation in the treatment of hip dysplasia. This condition is caused by an insufficiently formed hip socket and can lead to pain, instability and premature wear of the joint.
The current standard treatment is major pelvic surgery with a long recovery time. The new 3DHIP approach is based on successful applications in veterinary medicine, where similar implants in dogs led to better recovery and less pain. The patient-specific implant supports the hip without major bone correction and can contribute to better mobility and delay the need for an artificial hip in the long term.
