Doctors at the Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, have developed a new method to classify ankle malunions, a condition where the ankle bone heals in a wrong position after a fracture. This new system, called the Patel–Dhillon Classification, was created by Dr Sandeep Patel, Associate Professor in the Department of Orthopaedics, and Dr Mandeep Singh Dhillon. Their research has been published in the Indian Journal of Orthopaedics.[1]
The announcement was made in November 2025, soon after the publication of the research. PGIMER, known for its medical innovation, has contributed another milestone in orthopaedic research through this work.
Ankle fractures are common, but when they do not heal properly, patients often face pain, stiffness, and difficulty walking. This incorrect healing, called malunion, happens when bones shift or rotate slightly during healing. Such deformities can also lead to arthritis and long-term mobility problems. Dr. Sandeep Patel, Associate Professor, Department of Orthopaedics, PGIMER, Chandigarh said to The Indian Express:
Ankle malunions have long been considered difficult to manage, with fusion often seen as the only solution. Through this classification, we aim to provide clarity and direction to surgeons in analysing the deformity comprehensively and choosing corrective, joint-preserving procedures wherever possible. It represents an important step toward restoring both form and function in patients who otherwise would have lost their ankle joint.Dr. Sandeep Patel, Associate Professor, Department of Orthopaedics, PGIMER, Chandigarh
Until now, doctors had limited ways to categorise ankle malunions and plan the best treatment. In many cases, the only option for severe deformities was ankle fusion (arthrodesis), a surgery that permanently fixes the joint in one position to stop pain but also ends ankle movement.
With new surgical methods, doctors can now correct the bone alignment while keeping the joint intact. But for that, a clear system was needed to describe the deformity, understand its severity, and guide the surgery. The Patel–Dhillon Classification provides exactly that, a structured way to assess what went wrong and how it can be corrected.[1]
The new classification helps doctors study ankle malunions from three key perspectives:
Bone alignment: How far the bone has shifted from its original position.
Joint involvement: Whether the deformity affects the actual ankle joint surface.
Mechanical balance: How the misalignment impacts walking and body weight distribution.
By categorising the deformity under these parameters, surgeons can plan corrective procedures such as bone reshaping or repositioning instead of jumping directly to joint fusion. In simpler terms, the system acts as a guidebook for doctors to choose treatments that preserve natural movement whenever possible.
For patients, this new classification means more personalised care and better surgical outcomes. Someone with a previously “hopeless” ankle deformity may now have a chance to regain movement through reconstruction rather than a fusion procedure.
It also ensures that patients get consistent evaluations, no matter which doctor or hospital they visit, because the classification gives a common language for describing deformities.
While the Patel–Dhillon Classification is an important step, further studies will test how well it works across different hospitals and patient groups. Researchers will also assess whether different doctors interpret the same X-rays in the same way using this system. Once validated, it could become an international reference for orthopaedic surgeons managing ankle malunions.[1]
The Patel–Dhillon Classification, developed at PGIMER, Chandigarh, is a new scientific tool to help doctors better understand and treat ankle deformities that result from improperly healed fractures. By giving surgeons a systematic way to assess the problem, it promotes treatment options that preserve the joint, maintain mobility, and improve quality of life for patients.
1. Patel, S., Dhillon, M.S., Baburaj, V. et al. Ankle Malunion: A Systematic Case-Based Approach to Treatment and a Modified Classification. JOIO (2025). https://doi.org/10.1007/s43465-025-01582-4
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