CLINICAL MOVEMENT ANALYSIS - A CASE FOR INTEGRATION OF TECHNIQUES AVAILABLE - a complicated diabetic foot

by Jonathan Small
Royal Leamington Spa Rehabilitation Hospital Gait and Movement Analysis Service

Summary
Gait assessment laboratories have been used very successfully for many years to assess children with cerebral palsy.  The use of such laboratories enables precise surgical intervention, physiotherapy and orthoses to be prescribed.  However, until recently, there has been no equivalent clinical service in the UK for adults who have had strokes, head injuries and other neurological problems, including those with diabetic neuropathy.
This paper intends to highlight the advantages of a multidisciplinary, technologically-advanced Gait and Movement Analysis (GAMA) Service for medical patients through discussion of a specific case report.

A view of the GAMA lab with Vicon, five team members and an undernourished visitor

Background
The Royal Leamington Spa Rehabilitation Hospital is a 30-bed unit that specialises in the rehabilitation of adults who have suffered neurological injury (e.g. stroke, head injury) and the GAMA Service is primarily used for assessment of those patients.  However, it was soon realised that other client groups could benefit from this specialised service, referrals from various medical fields have been accepted, including rheumatology, orthopaedics, general surgery, paediatrics, neurology, and diabetology.  Through charitable donations and Trust support the laboratory now has state-of-the-art equipment and a highly-trained multidisciplinary team, which enables the following to be performed:

* Full clinical assessment.

* 3D kinematic analysis using Vicon 370 3D motion analysis system (Oxford Metrics, UK).

* 3D kinetic analysis using Vicon 370 3D motion analysis system in conjunction with an AMTI Force Platform (Advanced Mechanical Technology Incorporated, USA).

* Balance assessment using Vicon 370.

* Foot pressure analysis using Pedar Foot Pressure Measurement System (Novel, Germany).

* Observational video analysis using 3-camera JVC system linked to an s-VHS video recorder.

The Case Report

Introduction
The complications of diabetes are well-known and well-published.  One of the major complications that affects both quality and quantity of life is diabetic foot ulceration.  This is commonly associated with foot deformity and sensory neuropathy, and can lead to significant financial burdens for both the patient and the NHS.
Current high-technology research emphasis in the diabetic foot is in foot pressure measurement, particularly in shoe techniques.  It is known that high plantar pressures result in ulceration in the diabetic neuropathic foot, and management techniques are geared towards reduction of those pressures.  However, there has been little research that looks at the effect of diabetes on other gait parameters.  Clinical movement analysis laboratories in the UK are few and far between, and those that integrate three-dimensional motion analysis techniques with in-shoe foot pressure measurement techniques are even harder to find.
This is a case study that describes the combined use of these techniques in the assessment of a patient with complex problems and difficulties.

History
The patient was diagnosed with type 2 diabetes in 1989, which is now controlled with daily insulin injections.  Around that time, he underwent a lumbar spine laminectomy and nerve root decompression at S1 level.  For the next five years his diabetes was not well controlled.
In 1995 he developed a painful callosity on his right foot, located under the right 5th metatarso-phalangeal (MTP) joint which was subluxed.  This was managed in a hospital-based, multidisciplinary Diabetic Foot Clinic utilizing pressure-relieving insoles and special/modified footwear.  In 1997 sub-callous ulceration developed. Conservative treatment failed to cope with the problem, and a year later he underwent surgery in an attempt to correct the plantarflexed 5th metatarsal with dorsally-displaced 5th proximal phalanx. The surgery involved a metatarsal osteotomy and joint arthroplasty, which allowed the plantar ulceration to heal without recurrence to date.
A few months post operatively a painful, swollen mass appeared near the right lateral malleolus with develop-ment of an inversion deformity of the right rearfoot.  There was generalised lateral pain in the right foot, which was treated with footwear modifi-cations. These were partially successful, but nerve conduction studies in 1999 confirmed generalised axonal sensorimotor neuropathy.
The patient was referred separately by both the Consultant Diabetologist and the Consultant Orthopaedic Surgeon to the Gait and Movement Analysis (GAMA) Service, Royal Leamington Spa Rehabilitation Hospital (RLSRH). The latter Consultant was considering extensive rearfoot surgery in an attempt to relieve the discomfort and reduce further foot deformity, but was reluctant to proceed due to other possible diabetic foot complications e.g. Charcot neuroarthropathy.

Assessment
A full clinical gait analysis assessment was therefore carried out at the laboratory. The specialist multidisciplinary clinical team then analysed the results of the gait analysis, involving collation and interpretation of data from video, kinematics, kinetic, clinical examination, foot pressure measurement, and radiology.  An extensive report was produced, of which the main findings and recommendation have been included here.

Main findings:
* Very limited motion of pelvis in sagittal plane, leading to probable reduced ability to absorb shock.
* Increased loading response bilaterally, but left more than right with increased knee extending moment.
* Abduction of right hip throughout gait with reduced hip abducting moment.
* Pain in left hip on end of range of internal and external rotation.
* Reduced plantarflexion and corresponding reduction in total ankle power of right foot at final contact. Altered biomechanics of ankles and feet bilaterally:
- both heels remain inverted throughout gait, more so on the right
with associated increased ankle abducting moment
- fixed plantarflexion of the hallux bilaterally limiting normal pronatory lowering of the foot and associated rearfoot eversion,
- all toes remain hyperextended at the metatarso-phalangeal joints,
- the lesser digits are clawed.
* Localized areas of excessive perpendicular pressure under the sole of the foot during walking which increases the risk of ulceration due to diabetic neuropathy;
- high peak pressure areas under both lateral heel and both 5th metatarsophalangeal joints,
- high mean and peak pressure under the left 1st metatarso-phalangeal joint,
- high mean pressure under the right styloid process area.
* Stress fracture of base of 4th metatarsal proximally (x-ray dated 22/02/1999 and noted in radiology report).
* Possible avulsion of tuberosity of right cuboid noted on the x-ray dated 20/08/1998 (not noted in radiology report) which could have resulted from any of the following:
- increased weight-bearing pressure directly on the area from the inverted position of the foot leading to weakening, rarefraction, then shearing of the boney prominence,
- increased pull on peroneii in an attempt to evert the inverted foot,
- any combination of the above.

Recommendations
* MRI of foot for further investigation of right cuboid area with the possibility of surgical intervention.
* Repeat x-ray of right foot to investigate the fracture site and monitor any deterioration.
* Close monitoring for Charcot neuroarthropathy, which is a destructive complication of diabetes that can develop after pathological fracture.
* Continued provision of diabetic boot-style footwear with casted palliative insoles due to cavoid foot shape and to provide ankle support.
* Lateral heel flare modification to diabetic footwear to limit foot inversion in early stance.
* Modifications to existing insoles to further reduce plantar pressures and alter foot function. A lateral forefoot wedge modification is required, but care should be taken to gradually increase the degree of wedge correction until maximum improvement is achieved.
* Repeat foot pressure assessment after provision of footwear and insole modifications to assess efficacy.
* X-ray of left hip to investigate cause of pain.