C-Brace: The future of orthotic technology

by Articles , June 20, 2014

Orthotic bracing is changing. As new technology, extensive research and new light-weight materials emerge we can expand the way we practice.
For people with problems ranging from isolated quadricep weakness, to polio, post-polio, multiple sclerosis, unilateral paralysis, incomplete spinal cord injury and some traumas, walking can be a challenge. Technology is helping us overcome this challenge and a new wave of orthotic bracing is pushing the boundaries of orthotic care.

In recent years, Stance Control Orthoses, and now Stance and Swing Control (SSCO®) have changed the way we approach bracing – from a static, always-locked or always-unlocked approach to new dynamic systems that unlock only when needed. Compared to walking with a locked leg brace, a stance-control orthosis is a brace that helps create a more natural stride. Stance control means that instead of stability coming from a locked knee joint, the brace is able to lock and unlock at just the right time while walking.

So what does this new technology mean for the user? You may have seen or experienced a hip hike or other unnatural motions that come from walking with a locked knee brace. A stance control brace helps avoid the physical strain and damage these abnormal movements can cause over time. Stance control braces closely mimic natural gait (or walking), and help the wearer cover the variable terrain they face every day, from carpet and grass to uneven, rocky ground. This all means more energy can be spent moving forward with a great deal less wear and tear on the body.

New Technology
This year, the world’s first intelligent, electronic orthosis has pushed the boundaries of stance control and is allowing people who were previously wheelchair-bound, to walk again. The C-Brace, the world’s first Stance and Swing Phase Control Orthosis (SSCO), is a custom orthosis controlled by a computer and sensors.

The C-Brace® orthotronic mobility system is made by manufacturer Ottobock and is the culmination of their advanced prosthetic technology and orthotic expertise. With this new technology has come a new word – ‘orthotronics’. Orthotronic is the use of electronic or computer-controlled orthotic bracing that creates a sophisticated way to measure gait. Unlike conventional orthoses, the C-Brace (SSCO) reacts intelligently to its environment. The unique combination of sensor technology and an integrated microprocessor make it possible to control hydraulic stance and swing phase in real time. This means the patient is supported in every position throughout their gait pattern.

The intuitive function of the C-Brace improves the user’s mobility and safety, so the user doesn’t have to concentrate on every step. It adapts to movements that most of us take for granted, such as changing walking speeds, handling sudden obstacles, descending stairs and ramps step over step, walking on uneven ground and even bearing weight with flexed knees – such as sitting down or standing up. The microprocessor in the brace allows it to be completely customised for the individual and additional settings can even be tailored to activities such as bike riding.

The benefits of orthotronics are not limited to day-to-day comfort and stability for the user. The C-Brace promotes a natural posture and can prevent or reduce excessive unilateral physiological stress and the long-term damage it may cause.

A 59-year-old patient Karin describes, “I put on the orthosis system, started walking and it was a whole new experience. Somehow my locked leg had always been in the way. Now I move more smoothly, normally. Stepping down, for example when walking down stairs, is much more natural.” She has also noticed an improvement in her health. “Since my gait is supported now, I experience less back pain, especially when walking down slopes. My sound left side is not subject to as much strain.” Karin likes to play with her grandchildren in the playground. She can now easily crouch down, walk on sand, react quickly and sit down without effort. Her dog Pepi benefits from her new-found mobility too, enjoying long hikes and bike rides in any weather. “The whole family has noticed I’m much more mobile these days!”

Construction & Function

The C-Brace is made from PrePreg fibre composite material and consists of upper and lower leg shells and a foot piece, which are all hydraulically controlled by the lateral C-Brace joint unit. A sensor-integrated fibre composite spring connects the foot element with the shell of the lower leg. From this spring element, an ankle movement sensor transmits the current gait phase to the knee unit, which is integrated into a carbon fibre frame along with the electronics. At the same time, a knee angle sensor continuously measures the flexion of the knee joint and its angular velocity.

Key features
Stumble Control: Resistance to uncontrolled knee flexion when sensors read a moment of instability gives the time necessary to recover.
Real-time Gait Analysis: Every period of gait in the gait cycle is controlled dynamically and in real time, allowing the patient to walk with more ease and less concentration and also with less compensation of the sound side and torso.
Standing and 2nd mode: Additional modes allow for comfortable static standing and additional settings (for therapy or other activities).
Stance Extension Damping: Progressive resistance allows natural movement to occur without uncontrolled and early knee and hip extension at Terminal Stance, resulting in a more natural movement, without abrupt changes to the centre of gravity, lower back and lower limb joints.
Stance Flexion Damping: Controlled, partial knee flexion while weight bearing allows the patient to maintain knee control when walking down hills and ramps, descending stairs step over step, and while sitting down onto a chair.

The microprocessor in the brace recognises in real time the phase of the user’s gait cycle and, as such, regulates the hydraulic resistances and controls flexion and extension. Due to the continuous calculation (50 times a second), the C-Brace is able to optimise the gait pattern in every single phase.

The primary indications for C-Brace include: lower limb involvement with weakness or paresis of the quadriceps muscle or the inability to maintain knee extension during stance phase, e.g. incomplete paraplegia with segmental levels of L1 to L5 or polio, post polio syndrome. Contraindications include:
Moderate to severe lower limb spasticity.
Hip flexor strength of less than
grade 3. Ability to advance the limb by compensatory trunk movement is permitted.
Fixed knee valgus greater than 10 degrees beyond anatomic neutral.
Fixed knee varus.
Less than 2 degrees of relative ankle dorsiflexion.
Body weight over 125 kg/275 lbs.

For the Clinician

This new technology is pushing the boundaries of our knowledge and experience as orthopaedic technicians. Therefore, Ottobock as the manufacturer offers obligatory certifications for orthopaedic technicians so they can provide patient fittings and are able to take advantage of the many functions C-Brace has to offer.

The course provides extensive knowledge about stance control as well as the technical details of the fitting process. Use of the adjustment software ‘C-Soft 2.6’ for individual configuration of the orthosis is also included in the C-Brace certification course. This easy-to-use software allows clinicians to monitor the patient’s movement cycle while at the same time analysing each and every gait phase via Bluetooth.

As the world’s first stance and swing phase-controlled orthosis, C-Brace opens up unprecedented possibilities in the field of neuro-orthopaedics. User-friendly software allows the orthopaedic technician to adapt the orthosis to fit the user’s needs and lifestyle. The materials are light-weight, flexible and robust and power is supplied by a long-life lithium battery, ensuring it is comfortable and easy to use. The combination of these innovative characteristics means the C-Brace can offer more mobility and security for patients suffering from paralysis of the lower extremities.
It does take time and dedication to learn to walk with these devices, and to unlearn the compensating movements used to walk with a locked knee brace. That investment is well worth it, though, to be able to more easily navigate through life.

Custom built, light-weight, strong and stable, the future of orthotics is most certainly in stance control orthotic braces and it will be exciting to see how the technology continues to evolve to benefit those with limited mobility.