Can Patients with Severe Knee Deformity Benefit from Partial Knee Replacement? Evidence from a Clinical Study

Partial knee replacement, also known as unicondylar knee arthroplasty (UKA), is a surgical option commonly discussed for patients with arthritis affecting a single compartment of the knee. Traditionally, severe knee deformity has been viewed as a relative contraindication for this procedure. However, emerging clinical research has examined whether UKA may still be considered in selected patients with more pronounced deformities. A peer-reviewed clinical study co-authored by Dr Seng Chusheng and colleagues provides insight into outcomes and implant survivorship of partial knee replacement in patients with severe knee deformity. This article outlines the study’s findings and their relevance to orthopaedic practice.

Overview of Severe Knee Deformity and Its Clinical Challenges

Severe knee deformity often occurs in the context of advanced osteoarthritis, where long-standing joint degeneration leads to significant angular deviation of the limb. This may present as varus (bow-legged) or valgus (knock-kneed) alignment, affecting load distribution across the knee joint. From a surgical perspective, such deformities can complicate implant positioning, joint balancing, and long-term function. As a result, careful assessment is required when considering surgical options, particularly when partial joint replacement is being evaluated.

What Is Partial Knee Replacement (Unicondylar Knee Arthroplasty)?

Partial knee replacement involves resurfacing only the affected compartment of the knee while preserving the remaining joint structures. Compared with total knee replacement, UKA addresses a more localised area of damage and is generally discussed for patients with disease confined to one compartment. Historically, severe deformity has raised concerns regarding alignment correction and implant longevity in UKA. These concerns have influenced patient selection criteria, making severe deformity a subject of ongoing clinical evaluation rather than routine indication.

Overview of the Singapore-Based Research Study

The referenced study, published in Knee Surgery, Sports Traumatology, Arthroscopy, examined outcomes and implant survivorship of unicondylar knee arthroplasty in patients with severe knee deformity. The research compared this group with a matched control cohort without severe deformity. The study assessed functional outcomes using validated scoring systems, alignment correction, and implant survivorship over a defined follow-up period. Dr Seng Chusheng was among the contributing authors, participating in the clinical research and analysis.

Key Findings on Outcomes and Survivorship

According to the study, patients with severe knee deformity who underwent unicondylar knee arthroplasty demonstrated functional outcomes that were comparable to those of the matched control group. Outcome measures included knee-specific functional scores and quality-of-life assessments. Implant survivorship rates reported in the study did not show a statistically significant difference between patients with severe deformity and those without. These findings suggest that, within the study population, severe deformity did not necessarily correspond to poorer short- to mid-term outcomes following UKA. It is important to note that the study’s findings are specific to the cohort examined and are influenced by surgical technique, patient selection, and follow-up duration.

Implications for Orthopaedic Practice

From an orthopaedic perspective, this study adds to the growing body of evidence examining the boundaries of partial knee replacement indications. It highlights the importance of evidence-based evaluation rather than reliance on deformity severity alone. Ongoing research and long-term follow-up studies remain important for understanding how outcomes evolve over time and how surgical decision-making can be refined.

About the Research Contributor

Dr Seng Chusheng is a Consultant Orthopaedic Surgeon with training in knee surgery and involvement in clinical research. He holds a Bachelor of Medicine and Bachelor of Surgery and a Master of Medicine in Orthopaedic Surgery from the National University of Singapore, and is a Fellow and Member of the Royal College of Surgeons of Edinburgh.

Importance of Clinical Research in Knee Surgery Decision-Making

Clinical studies play an important role in examining established assumptions in orthopaedic surgery. Research such as this provides data that may inform patient selection, guide further investigation, and support discussion between clinicians and patients when considering surgical options.

References

• Seng C.S., Ho D.C., Chong H.C., Chia S.L., Chin P.L., Lo N.N., Yeo S.J. Outcomes and survivorship of unicondylar knee arthroplasty in patients with severe deformity. Knee Surg Sports Traumatol Arthrosc. 2017. PMID: 25466278.