New home device to treat severe stiffness and pain following knee surgery

Dr Sara Aspinall

Director, STAK Orthopaedics

Patients with arthrofibrosis — a debilitating condition characterised by excessive scar tissue around the knee joint — suffer from loss of motion, stiffness and sometimes significant pain.

Arthrofibrosis (commonly known as stiffness) poses challenges in treatment, as conventional physiotherapy typically falls short, offering limited appointments. Home exercises lack the necessary intensity required to break down dense scar tissue, the cause of the problem.

Knee device for severe stiffness and pain 

Dr Sara Aspinall, a specialist knee physiotherapist, has introduced a groundbreaking solution for knee replacement patients suffering from stiffness. Her innovation offers hope to the approximately 20% of knee replacement recipients who are left dissatisfied. 

Dr Aspinall’s research has led to the development of the STAK (Self-Treatment Assisted Knee) — a medical stretching device designed to empower patients with high-intensity stretching that can be performed in the comfort of their homes. This novel approach restores the knee’s range of motion and enhances overall quality of life. 

Improving range of motion 

In an eight-week clinical trial published in the Bone & Joint Journal, patients using the STAK achieved a remarkable 30° increase in range of motion on average, compared to just 8° for those receiving standard physiotherapy. When the standard treatment group incorporated the device for an additional eight weeks, they saw an additional mean increase of 20°. 

Patients report immediate benefits,
with increased mobility and comfort
after their initial session.

Feedback from professionals 

The device has earned widespread praise from leading surgeons, physiotherapists and patients throughout the UK. Professor Robert Ashford, from UHL NHS Trust, describes it as: “A simple yet highly effective daily routine with really excellent functional results.” Fellow consultant orthopaedic surgeon Steven Godsiff lauded it as a: “Fantastic, low-cost and highly effective alternative treatment.”  

Liz Jacobs and Jack Codd, knee specialist physiotherapists at the Royal Devon and Exeter Hospital, highlight the device’s user-friendliness and convenience. “Patients can control the stretch intensity, track their progress, ensuring a safe, effective and motivating rehabilitation process.” 

Professor Andrew Toms, National Clinical Lead for Revision Knee Surgery, highlights the importance of addressing stiffness in knee replacements. “Our role as surgeons, physios and researchers is to keep innovating to help solve this difficult multifactorial problem. The STAK tool gives us a new approach and has the advantage of being an active technique, with a prolonged flexion stretch.”  

Benefiting patients with severe knee stiffness 

Sara explains: “Patients report immediate benefits, with increased mobility and comfort after their initial session.” Gillian, 67, shared after her first session: “It feels as if I’ve loosened something off, and I can bend my knee more already!” Rhiannon, 73, expressed joy after four weeks of treatment: “I’m really happy I’ve got back to full life, and I feel 10 years younger.” With this device, there is hope for a pain-free future for patients who have endured the challenges of stiffness for too long.