Orthopaedic Surgery in CP: Multi-Level Surgery (MLS) for problems affecting the ability to walk

What is it?

Multi-Level Surgery in the lower limbs is the preferred technique for the treatment of problems associated with walking in children with Cerebral Palsy (CP).

CP is a common motor disability with features causing abnormalities of posture, balance and gait that may be of variable severity. Orthopaedic problems relate to abnormal muscle and joint function affecting the ability to walk normally. Many of these problems can become worse with time and growth and therefore need to be treated appropriately.

What are the common problems seen with the ability to walk?

Gait feature	Description
Antalgic gait	Pain affects the ability to put pressure on the affected side
Ataxic Gait	Unsteady and uncoordinated with a wide base of support
Dystonic Gait	Involuntary movements making the gait jerky and irregular
Short leg Gait	Short side foot drops down to equalize length OR long side knee stays bent

Features at the foot and ankle
Foot drop	Toe drag, tripping with reduced ability to lift the foot to clear the ground
Toe-toe gait	Heel doesn’t contact the ground- common feature with calf muscle involvement
In-toeing	Feet point inward
Out-toeing	Feet point outward

Features at the knee
Flexion (Crouch Gait)	Knee does not straighten when walking
Recurvatum	Knee straightens up too much- almost bending backwards
Stiff knee	Reduced arc of movement while walking

Features around the hip
Scissoring	Knees seem to hit each other while walking
Circumduction	Swinging leg out to avoid catching the knees or feet
Trendelenburg	Pelvis drops down and trunk sways to compensate for this

Trunk and Pelvis
Anterior Pelvic Tilt	Also associated with lumbar lordosis- increased arching of the lower back
Trunk Sway	Increased movement of the trunk: side to side or front to back.

How do you assess this?

In growing children with CP, in addition to the primary features of weakness, change in tone, selective motor control, there is also a continuing interaction between abnormal muscle activity and skeletal development. This allows a level of function that we understand using the Gross Motor Function Classification System (GMFCS).

Children who can walk are between Levels I to III. Reduction in ability is commonly due to ‘Lever Arm Dysfunction’, which refers to the disruption of a muscle- joint complex resulting in functional weakness and diminished power generation.

A decision-making pathway to understand this follows a typical process:

A comprehensive Medical History including parental questionnaires like the FAQ and the GOAL
A Detailed Physical Examination
Appropriate Imaging: XR, CT, EOS to identify and measure deformity of the skeletal structure
Instrumented Gait Analysis- also called 3DGA: to provide a detailed representation of the way the child walks.

This is analysed and discussed in a multi-disciplinary setting and problems with gait and function are identified as impairments. The solutions to these problems are then outlined and the suitable plan agreed by the team. Team members involved are the surgeon, physiotherapists, OT, orthotists, bio-medical engineers, rehabilitation specialists, case managers and social workers.

How do you treat these problems?

‘The decision is more important than the incision’.

Much thought, planning and discussion goes into the decision-making process. A list of options is considered, and the suitable choice is evaluated for benefit versus risk. The choice depends on the individual circumstances of each case and the nuance often calls for judgement in picking the right modality of treatment.

If surgery is selected as the preferred option, the final dose of surgery at each level is confirmed by an examination under anaesthesia, that confirms the pre-operative findings and fine tunes the decision-making process. Most of the surgical techniques are designed and executed to allow recovery and rehabilitation to be as quick and smooth as possible. Plans are in place to ensure the therapy and orthotic support is available as needed to facilitate a return to the pre-operative level of function as soon as feasible.

Femoral Derotation osteotomy with internal fixation with a Blade Plate: