Research Projects 1998
University Hospital, Sweden
The major part of the health care consumption in orthopedics is caused by joint
diseases (osteoarthrosis and rheumatoid arthritis), fractures, back problems, injuries,
and tumors. This pattern is reflected in the research activities within the Department
of Orthopedics at Lund University Hospital.
Research on joint disease and its consequences spans from basic biochemical investigations
to applied projects which monitor nationwide the outcome of arthroplasty and includes
the following aims: Develop methods for diagnosis and monitoring of early-stage
osteoarthrosis through patient-administered outcome scores, radiography, arthroscopy,
MRI and analysis of joint fluid and serum markers of cartilage turnover as well
as investigate the disease mechanisms; Improve diagnostic and reconstructive techniques
after knee ligament injury; Improve and develop techniques for joint replacement
in the rheumatoid joint; Study the process and causes of joint implant loosening
in hip and knee; In a nationwide, prospective multicenter study investigate patterns
of knee joint implant failure related to time, implant type, age, etc. Different
methods of treatment for gangrene of the lower extremity are evaluated with regard
to quality of life, cost, etc.
Fracture research includes: A study of the process of bone induction and its
stimulation by human recombinant growth factors; In a nationwide, prospective multicenter
study investigate the epidemiology and treatment of hip fractures and its effects
on health care economics; Improve methods for osteosynthesis of hip fractures and
study effects on femoral head vitality, fracture healing, and rehabilitation.
Research on lumbar back pain and sciatica aims to optimize patient information,
operation methods, postoperative treatment, and utilization of hospital resources.
Research on soft tissue sarcomas evaluates diagnostic procedures, surgical techniques,
and prognostic classification of tumors. Research in hand surgery includes evaluation
and treatment of ligament injuries in distal radius fractures in young patients.
Research in pediatric orthopedics targets gait and function analysis in children
with cerebral palsy and pathophysiology in Perthes' disease.
Laboratory facilities exist within the Department for the following areas: biomaterial,
biomechanics, cartilage metabolism, animal experiments, bone transplantation and
radiostereometry. In addition to the some 30 M.D. clinical investigators, a total
of 6 laboratory technicians, 5 engineers/engineering students and 4 secretaries
are engaged in the research work. Currently, a total 28 graduate students are working
on their Ph.D. thesis within the Department.
These research projects thus involve the whole staff at the Department of Orthopedics
at Lund University Hospital. In the interest of simplicity, only the responsible
primary investigator of each project is listed in the project summary. For further
details on any of these projects, as well as a complete listing of participants
in each project, please contact the primary investigator. A list of publications
printed in 1997 is enclosed. This annual report has been edited by Stefan Lohmander.
For further information you may also use our homepage
The two graphs below summarize some aspects of the academic activities of the
Department during the last few years.
|Published Scientific Papers
The research is financially supported by:
- European Community
- Swedish Cancer Society
- Swedish Medical Research Council
- Foundation for Strategic Research
- Alfred ?terlund Foundation
- Sports Research Council
- Federation of Swedish County Councils
- Greta och Johan Kock Foundations
- King Gustaf V 80-year Birthday Foundation
- Lund Healthcare District
- Malm?us County Council
- Faculty of Medicine, Lund University
- National Board of Health and Welfare, Sweden
- Stiftelsen f? bist?d ? vanf?a i Sk?e
- Swedish Society of Medicine
- Thelma Zo?a Foundation
- Trygg-Hansa Research Foundation
Osteoarthrosis (OA) is a major cause of disability and early retirement. Current
methods for diagnosis and assessment of progression are based on clinical and radiographic
signs. As a consequence, the disease is diagnosed only in its final stages and progression
is difficult to assess. We monitor the progress of post-traumatic knee OA after
injury to the cruciate ligament and meniscus and correlate results of patient-administered
outcome scores, radiographs, arthroscopy, magnetic resonance imaging (MRI) and biochemical
markers of cartilage metabolism. Prospective and retrospective studies to monitor
the development of OA, and the effect of intervention, after injury to menisci or
ligaments of the knee are ongoing. The prevalence of hip OA in Iceland and Sweden
is compared. Clinical trials of the effect of intraarticular injections of hyaluronan
in knee OA have been performed, other clinical trials of non-surgical treatment
of OA are planned.
Molecular fragments of the joint cartilage matrix are released to the synovial
fluid after knee injury and during the development of post-traumatic OA. Concentrations
of fragments of proteoglycan, cartilage oligomeric matrix protein, collagen, and
other matrix molecules released into joint fluid remain elevated for many years
after injury. High concentrations of the metalloproteinases (MMP) as well as tissue
inhibitor of metalloproteinases are found in joint fluid after injury and in OA.
Elevated levels of MMPs identify pathological joints with high sensitivity and specificity.
Although we find very high concentrations of MMPs in joint fluid after injury, the
role of these proteinases in cartilage destruction in OA remains unclear.
We find a consistent N-terminal in proteoglycan fragments in joint fluid in OA
and in rheumatoid arthritis which corresponds to a specific cleavage of the core
protein in the interglobular domain. This suggests a common final degradation step
of proteoglycan in these joint diseases. The identity of the proteinase remains
elusive but would be of great value in efforts to identify one of the mechanisms
for proteoglycan breakdown in OA. In continued work we immunolocalize specific cleaved
matrix molecule fragments in human OA and RA cartilage and joint fluid.
A patient-administered knee and osteoarthritis outcomes score has been developed
and validated for patients with lesions of the anterior cruciate ligament and/or
meniscus and post-traumatic OA. The score assesses pain, other disease-specific
symptoms, function of daily living, function of sports and recreation, and quality
The prevalence of hip OA in Iceland is several-fold higher than in Malm?City,
Sweden. We are searching for genetic defects in the Icelandic population that may
be one of the reasons for the high prevalence of hip OA.
The long-term goals of this project are (1) to characterize the natural
history of post-traumatic OA and the effects of surgical and pharmacological intervention,
(2) to identify risk factors and disease mechanisms in OA, and (3)
to identify body fluid markers of OA which could be used in early diagnosis and
monitoring of the disease. Such knowledge would facilitate efforts to develop drugs
which could retard the destruction of joint cartilage in OA. The work is done in
collaboration with Laboratories and Departments in Sweden, Iceland, Norway, Finland,
England, Germany, USA, Canada, and Japan.
Knee injuries may affect collateral and cruciate ligaments as well as menisci
and joint cartilage. A typical injury is the consequence of an indirect twisting
force in mainly young and middle-aged people. An injury of the anterior cruciate
ligament which is left untreated may result in symptoms of instability and pain
and problems to master many sports activities and strenuous work. Our present research
relates to the sensory function of the limb after an anterior cruciate ligament
injury and the value of different training programs. The stability after anterior
cruciate ligament reconstruction is studied by radiostereometry. The value of suturing
the meniscus injury is also evaluated.
In the long prospective there is an increased risk of developing arthrosis (OA)
of the knee joint. We are studying the sensory function of the limb in arthrosis
of the knee and also after different surgical procedures like osteotomy and arthroplasty.
Treatment by wedge osteotomy has been studied in Lund since many years while osteotomy
by callus distraction (CD) has been used only the last few years. A randomized study
comparing traditional wedge osteotomy to CD osteotomy has been completed. Further
studies on CD in more advanced OA in younger patients as well as this operation
in lateral OA are also studied. Complications in callusdistraction (in a national
project), gate analysis, bony healing in CD as well as mechanical lode testing are
evaluated. The risk of pin inflammation - infection is studied in a randomized way
comparing open and closed care of the pin incision.
Operation of OA by an endoprosthetis joint replacement is one of the most successful
treatment programs in orthopedics. None optimal placement of the artificial joint
and by time the risk of loosening is one common reason for failure. Our project
is the study of loosening in relation to the perioperative mechanical trauma to
the bone tissue. The surface is studied both regarding evenness and direction of
the cut and also the possibility of bone tissue regeneration. The soft tissue is
studied with the aim to minimize surgical incision of the skin and underlying soft
tissue in order to decrease postoperative pain and to facilitate rehabilitation.
The surgical technique is studied by traditional cutting compared to computer and
robotic cutting. This is a high technology procedure divided into three parts: planning,
registration and the cutting of the bone. This part of the project is performed
in corporation with the Rizzoli Clinic, Bologna, Italy. Another projects is unicompartmental
endoprosthesis and minimal invasive surgery. Also long time follow-up of different
cemented and noncemented prosthesis by clinical and radiographic (including radiostereometry)
methods are performed.
Instability of the cervical spine can be managed in several ways. Posterior fusion
and/or decompression may include one or several levels and different types of internal
fixation may be used. The clinical and radiographic results of different surgical
methods are under investigation. Dynamic studies of the cervical spinal canal with
magnetic resonance imaging apparatus will be started, as well as epidemiological
studies on the incidence, natural course and surgical treatment results of arthritic
involvement of the thoracic and lumbar spine.
The clinical and radiographic results of modular endoprostheses for the hip and
knee are continuously followed. Our design of a knee joint prosthesis has now been
in clinical use since 13 years, and the relation between the radiographic positioning
of the prosthesis and the clinical outcome will be defined.
A multicenter study on bipolar shoulder prostheses will start during the year.
We have recently reported the results of two different methods for arthrodesis
of the rheumatoid ankle. Endoprosthetic replacement of the ankle joint will start
in 1998 and a number of patients will be followed with roentgenstereophotogrammetric
analysis. A prospective study of different surgical methods for forefoot surgery
is also in preparation.
The JCA surgery register is under continuous development. An individual patient
information system is under development and re-examination of about 150 children
operated with different large joint prostheses will start in the near future.
The overall aim of the project is to develop improved biomaterials
for increased implant survival, to obtain a better understanding of the biomaterial
tissue interface, and to exchange knowledge between different disciplines
and institutions. The project consists of a basic/preclinical part and a clinical
part. The basic/preclinical part will (1) focus on molecular and cellular
binding patterns and mechanics of existing and new chemically and structurally tailored
surfaces. (2) The biological function of hydroxyapatites as replacement, implant
coating and as a filler in PMMA will be studied. (3) Research on material degradation
will focus on polymers in bearing surfaces and around implants to study chemical,
physical, mechanical, biological and tribological properties. From a material science
perspective a prime objective is to build a competence in artificial joint tribology
and to develop reliable in vitro screening methods for assessing the wear of material
combinations. (4) New predictive preclinical evaluation techniques for a better
joint implant fixation and survival will be developed. The clinical parts
will (5) be using RSA and several other imaging techniques measuring implant motion
and degradation. (6) Multicenter survival studies including outcome measurements
will be used for the clinical biofunction evaluation. This part includes a retrieval
and patient donor program.
Ad (1). Materials will be modified to achieve different tissue organization by
functionalization of the surface by attachment of biologically active ligands primarily
chosen from normally occurring matrix components. Techniques to characterize and
quantitate tissue organization will be refined. In the future the susceptibility
of the modified surfaces to bacterial infections will be investigated.
Ad (2). Experimental models which are closer to clinical applications will be
designed. The idea is to use ceramics or bone grafted knee prosthesis in rabbits,
in which we will try to stimulate incorporation and remodeling of the grafts by
e.g. growth factors. A micromotion chamber model will be used for further characterization.
Ad (3). Reciprocating pin-on-plate wear simulations will be carried out on different
material combinations. Novel candidate materials will be investigated, as well as
current materials (e.g. UHMWPE) that have been modified (plasma technology, microfabrication,
and polymer processing). The chemical and structural properties of the materials
will be characterized prior to and after testing by using spectroscopic and microscopic
techniques. Analysis of components from retrieved clinical and donor implants constitutes
a reference to the in vitro studies.
Ad (4). Different tissue differentiation processes in the prosthetic bone interface
are studied in a biphasic FEA program on endoprosthetic replacement with validation
of this material using experimental and clinical tools including RSA.
Ad (5). A retrieval program has been implemented for patients who are entered
into a RSA study group. Thus, approximately 200 patients have agreed to donate their
knee prostheses for post-mortal biomechanical and histological examination. The
preparation and histology will be carried out at GU and the biomechanical studies
in a new laboratory under construction in Lund.
Ad (6). A national implant and biofunction study is run by the Department of
Orthopedics in Lund, including all clinics in Sweden. In a later stage of this program
alternative material will be followed by multicenter survival analysis in the register.
Endoprosthetic components loosen at a rate of about 5_10% after 10 years, a process
in itself or in close liaison with the problem of wear of endoprosthetic components.
The project aims at understanding and alleviating this problem.
RSA has shown that prostheses usually move in relation to the bone they
are fixed to. It has recently been established that the pattern of this motion has
a clinical connotation and prostheses at risk can be identified by RSA after about
two years both in the hip and in the knee. Using the migratory pattern as end-point
and primary effect variable, changes in design, operative technique, fixation concepts
etc. can be studied prospectively in controlled studies. Thus a number of patient
cohorts are presently being followed and factors like bone preparatory technique,
cement / non-cement fixation, pressurizing cementing techniques, hydroxyapatite
coating, meniscal bearing designs and periapatite coatings are being assessed. About
800 hip- and knee arthroplasties are presently being followed by RSA.
Patients having had their knees replaced are asked to donate them post-mortem
in a retrieval program. Retrieved prostheses are processed for histologic examination
and the cellular process corresponding to migration and inducible displacement as
measured by RSA is investigated. Presently approximately 200 patients have donated
their knees and 25 cases have been retrieved. Further, retrieved specimens are tested
in an Instron materials testing machine for experimental correlates to RSA findings
from stress examinations.
Forces and motions across the bone-prosthetic interface can be modeled using
Finite Element Models (FEM). Using iterative algorithms, tissue differentiation
can be modeled and findings from retrieval specimens and animal models are being
used for validation purposes.
The development of endoprostheses over the last decades has concentrated on functionality
as assessed by gait analysis. The VICON system of OTC has been put to use
in this respect and significant relationships with RSA findings have been established.
Conventional clinical instruments for follow-up have not correlated with the proven
predictive ability of RSA. Outcome instruments in the form of questionnaires
have, however, been found to be both valid, sensitive and reproducible instruments
that can be administered though mail-outs. Within the frame-work of the Swedish
Knee Arthroplasty Project (see Optimized biomaterials for tissue reconstruction),
outcome instruments will be applied to knee arthroplasty patients in a large-scale
mail-out study in order to arrive at the finer nuances of well-being after joint
replacement. It is anticipated that differences between individual prosthetic designs
and modes of fixation can be identified.
Amputation frequency has increased during the last 50 years. More than 50% of
all amputees suffer from diabetes. A research program at our department has shown
that the number of amputations has decreased with two thirds during the last 10
years and that the amputation level is more distal than before. Twenty-five percent
of the amputations in diabetics now are performed through the foot.
A detailed analysis and follow-up of more than 1000 diabetic patients with foot
ulcer is performed, showing that two thirds of all amputations in diabetics are
initiated by a small foot ulcer second to narrow shoes or shear stresses on the
foot because of overloading. Very thin insoles with electronic sensors are placed
in the shoes of the patient and dynamic pressures are analyzed with a computer.
Special insoles and shoes are then made and the procedure is repeated to register
if the intended unloading effect is achieved, thus leading to prevention of ulcers
and eventual amputation. Special interest is focused on patients with diabetic polyneuropathy.
Factors related to healing of diabetic foot ulcers and specific treatment modalities
of diabetic foot ulcers and neuroarthropathy are evaluated. Several prospective,
randomized placebo-controlled studies are in progress: (1) supplementary nutrition
to diabetics with Wagner grade 1-2 lesions, (2) granulocyte-colony stimulating factors
to diabetics with foot infections and (3) bisphosphonates for diabetic Charcot neuroarthropathy.
Several patients with major amputation (below knee or more proximal) get problems
with the fitting of the prosthesis socket. A new concept, the Tec Interface socket
made from polyurethane, is now evaluated with respect to socket fitting and improved
walking ability with the Vicon gait analysis system which gives a 3-dimensional
view of human gait. Initial results are promising with a considerable improvement
of patient's satisfaction and walking ability compared to conventional sockets.
Aim: The aim is to reduce local bone loss, to replace bone and to stimulate
local bone formation.
Background: Bone loss is an essential problem in orthopedic conditions
such as tumors, infections, fractures, rheumatoid diseases and the loosening of
joint prostheses. If joint prostheses loosen, the surrounding and supporting bone
undergoes resorption and disappears. The reason for this bone loss is debated. Most
commonly the reaction to wear particles from the articulating surfaces are thought
to be the initiating factor. Missing bone can be replaced by bank bone, i.e. deep
frozen bone from other patients. Bank bone is associated with several problems including
the risk of transferring HIV virus. Attempts are made to replace bank bone with
porous hydroxyapatite and other materials. Bank bone and other bone replacement
materials incorporate slowly and incompletely. Incorporation of bank bone sometimes
also leads to break down and loss of its mechanical function. Similar break down
and collapse is seen for example in the femoral head after circular damage. Different
signal proteins can be utilized to stimulate bone formation. "Bone morphogenetic
proteins" (BMP's) can initiate bone formation extraskeletally in adult animals.
Bone induction by BMP's offer new therapeutic potentials for several orthopedic
problems. Other growth factors can also increase bone formation after local application
and this can be used to increase incorporation of bone replacement materials.
Animal experiments: We have developed a dozen different experimental implants
that are used in rodent experiments: Using titanium bone chambers, the reaction
of regenerating bone is studied after local application of various growth factors,
mechanical forces, fluid pressure, wear particles and also various kinds of systemic
treatment. We also use titanium plates, that are in contact with the bone surface.
The bone surface can then be subjected to a similar treatment as the regenerating
bone in the chambers. Different variants of this plate model is used to study aspects
on prosthetic loosening. We also use a knee joint endoprosthesis in rabbits.
Clinical series: We evaluate porous hydroxyapatite for bone replacement
in tibial condyle fractures. In a series of patients receiving knee join replacements,
we try to prevent prosthetic loosening by medication with a biphosphonate. We try
to enhance healing of posterolateral spinal fusions using BMP (all these series
are randomized and use roentgenstereometry as primary effect variable). We also
evaluate an injectable hydroxyapatite cement that hardens after the injection. This
is done in randomized series of distal radius fractures, partly using roentgenstereometry.
In retro- and prospective studies, distal radial fractures in younger adults are
studied in an attempt to find prognostic tools with radiography and arthroscopy
to define fracture subgroups that require surgical treatment.
Current results: Bone resorption similar to prosthetic loosening can be
induced by local fluid pressure. This is a new concept in the discussion about prosthetic
loosening. Morselization and impaction of bank bone impairs bone incorporation (contrary
to common belief), but mechanical load increases ingrowth and remodeling of the
graft. Bone callus can be induced to form hyaline cartilage by mechanical signals
only. Clodronate, but not alendronate, can reduce bone loss in a model of prosthetic
loosening. Bone and titanium can form a tensile resistant bond by chemosorption.
BMP's can decrease or stimulate bone formation depending on mechanical influence
or trauma. A good clinical effect of BMP's cannot always be anticipated. An injectable
hydroxyapatite cement enables rapid mobilization after a distal radius fracture,
but does not give a stable fixation.
Three of the participants in the project have their clinical position at the
Hand Surgery Unit in Lund.
Patients with hip fractures constitute one of the most resource consuming groups
in health care. They consume 25 percent of all bed days in orthopedic Departments
in Sweden. We have pioneered a treatment program with osteosynthesis, immediate
direct weight bearing, and continued walking rehabilitation in the patients own
home. During the last twenty years the incidence of hip fracture has doubled in
persons above 80 years of age and the total number of elderly in the population
increases. We must therefore continue the improvement in operation techniques and
rehabilitation of the hip fracture patients.
The research project contains epidemiological, prognostic, operative, technical
as well as rehabilitation and economical aspects on the hip fracture treatment.
It also includes a nationwide study of parameters for quality assurance. Projects:
(1) Fracture epidemiology, background factors, screening and prevention.
(2) Comparison of operation methods for multifragment trochanteric fractures.
(3) Investigation of femoral head vitality after femoral neck fracture.
(4) Hip joint tamponade after trauma. (5) Traction: Importance for
early reposition of cervical hip fracture. (6) Bone transplantation. (7)
Osteonecrosis. (8) Nationwide, multicenter registration of quality in treatment
of patients with hip fractures. Techniques: epidemiology, balance testing, patient
inquiries, skeletal scintimetry, tetracycline marking, bone biopsy, histology, MRI,
CT, X-ray, ultrasound, pressure measurement.
Surgical treatment of lumbar spine disorders based on improved resolution in
neuroimaging techniques is studied in a large prospective and consecutive study.
Pre- and postoperative patient related parameters are recorded and the outcome is
determined two years postoperatively. This database is continually expanding, and
a protocol for national registration of lumbar spine surgery has been composed and
is supported by the National Board of Health and Welfare. Preliminary results, so
far presented in more than 40 scientific papers, define suitable types of diagnostic
procedures and results after different types of spinal surgery. Outcome of decompressive
surgery for lateral stenosis, lumbar spine surgery in the elderly, and various stabilizing
procedures have been reported and clinical pictures have been scrutinized and prognostic
factors for surgery identified. A 5-year follow-up of operated central spinal stenosis,
carried out by an independent observer, has recently been concluded.
The study constitutes the basis for a treatment algorithm, enabling optimization
of (1) method and technique of operation, (2) postoperative treatment, (3) patient
information on treatment and long-term results, and (4) utilization of hospital
The analysis of motion and bone healing in the spine after surgery by roentgen
stereophotogrammetric analysis (RSA) forms an important aspect of this project.
With this technique, normal healing after uninstrumented posterolateral lumbar spine
fusion has been determined to occur between 6 and 12 months postoperatively. Further,
the significance of different types of postoperative orthoses has been explored.
A 5-month treatment regimen yields better results than a 3-month period. The type
of orthosis used, soft, stiff, or with hip immobilization, seems to be of minor
significance and the effect of the orthosis probably is exerted by minimizing gross
body motions instead of intervertebral mobility at the level of fusion. The healing
after instrumented posterolateral fusion occurs more rapidly and frequently than
without instruments. A concept for comparing the in vivo behavior of different types
of spinal implants has been developed. Fixation with biodegradable rods enhances
the fusion rate of the lumbosacral level. The external fixation test according to
Magerl is a valid prognostic instrument from the biomechanical point of view as
demonstrated by RSA. Lumbar spine mobility after decompressive surgery, mobility
after operation for thoracolumbar fracture, and comparative studies of different
implants in the lumbar spine are currently examined by RSA technique in separate
studies. One study evaluates in a prospective randomized fashion by means of RSA
the effect of bone morphogenetic protein (BMP) on fusion healing in humans for the
RSA analysis in degenerative disorders of the lumbar spine will increase our
understanding of intervertebral mobility in normal and pathological conditions.
The effects on function and ADL activities of lumbar disc surgery are being explored.
Non-invasive techniques for treating lumbar disc herniation are studied experimentally.
Soft tissue sarcoma comprises less than one percent of all malignancies. It is
a heterogeneous group of tumors; more than 30 different histologic types have been
defined. The clinical course varies, some tumors can be controlled by simple surgery,
others have a strong propensity both for local recurrence and distant metastases.
Prognostic factors are poorly defined.
Treatment: The principal treatment of soft tissue sarcoma is surgical
removal of the primary tumor. Amputation has been replaced by limb-sparing surgery,
sometimes combined with adjuvant radiotherapy. We evaluate the value of fine-needle
aspiration cytology for diagnosis, radiologic criteria for definition of tumor topography,
quality of surgical margins necessary for a low local recurrence risk, and the indications
for adjuvant radio- and chemotherapy.
Prognosis: Tumors are classified by light microscopy, electron microscopy,
immunohistochemistry, DNA-ploidy, proliferation factors determination, chromosomal
analysis, and molecular genetics. The findings from these investigations are correlated
with conventional histologic classification and clinical outcome.
Several of the projects are in cooperation with the Scandinavian Sarcoma Group,
the European Musculoskeletal Oncology Group and the Chromosomes and Morphology Study
Fractures of the distal radius are frequent in elderly, osteoporotic patients
and have been relatively well studied. In younger patients, higher energy trauma
is often involved and concomitant ligament injuries could be expected. The incidence
and severity of these injuries are largely unknown.
In an epidemiological study, distal radius fractures in young patients will be
analyzed, e.g., regarding fracture types and mechanisms of injury. Patients who
sustained a fracture 1-2 years ago, will be examined for carpal ligament injuries
using arthrography and arthroscopy. The relationship between ligament injuries and
subjective complaints will be studied.
In a prospective study, all younger patients with dislocated distal radius fractures
will be offered arthroscopic examination of the wrist in order to detect and classify
concomitant injuries of the carpal ligaments. Ligament injuries of different degrees
have been found in almost all of the more than 30 patients already examined. After
a one year follow-up of these patients, we hope to be able to detect which types
of ligament injuries that are likely to give permanent complaints. Different methods
of treatment of these ligament injuries will be studied in prospective, randomized
There is a substantial risk of increasing contractures of hip, knee and foot
in cerebral palsy. The untreated hip joint will often end up with dislocation. Apart
from threatening dislocation and impaired walking ability, hip contracture also
leads to sitting difficulties, hygienic inconveniences as well as increased tendency
of decubitus. An established dislocation is often painful with developing arthrosis
even in late teenage. If ominous signs are observed early enough deterioration can
be prevented by rather simple measures (orthoses, intensified physiotherapy, tendon
elongation etc.) and dislocation can likely be prevented. Today uniform follow-up
as well as firm rules for preventive treatment and follow-up of these children are
lacking. There is neither international consensus concerning prevention of late
complication by means of early taken measures; it is probably unique for Sweden
to manage a follow-up program of several years' duration.
A health-care program is designed with standardized assessment, treatment and
follow-up of all spastic diplegic and tetraplegic children in southern Sweden. A
central group (pediatric orthopedic surgeon, habilitation neurologist, physiotherapist,
orthopedic technician, radiologist, secretary) has been established responsible
for realization of the project.
Continuous directed controls are executed by the child's individual physiotherapist.
When necessary this is supplemented with radiological examination or video based
gait analysis as well as early taken measures according to defined criteria of treatment.
The purpose of the project is to:
- reduce the number of serious joint contracture and hip dislocation
- reduce the need for major late orthopedic operations in children
- reduce the requirement for more complicated sitting devices Continuous databased
documentation facilitates comparison with other treatment procedures and outlines
optimized way of treatment.
The etiology in LCPD is a disturbed blood supply to the proximal femoral epiphysis
resulting in an aseptic necrosis. The cause of this disturbance is unknown but scintimetric
studies indicate that synovitis with effusion in the hip joint and subsequently
increased intracapsular pressure is important. We have measured the intracapsular
pressure in LCPD and have found pressures that could compromise the blood supply
to the proximal femoral epiphysis.
A sonographic technique was developed to diagnose and follow the synovitis with
ensuing effusion. It was correlated to the corresponding findings on CT. Sonography
proved a very sensitive diagnostic tool in various forms of synovitis and subsequent
Synovitis causes cartilage edema and ensuing cartilage hypertrophy with a risk
of joint deformation, incongruency and poor containment. Serial MRI and plain radiography
was used to follow the development of the femoral head. In cases of incongruency
we have performed a proximal femoral varus derotation osteotomy. A recent follow
up study indicates that this results in a reduced cartilage incongruency and an
improved sphericity of the femoral head. The advantage with MRI in these cases is
the possibility to monitor the cartilage contour development of the head of femur
as well as the epiphyseal necrosis and synovitis. The cartilage reacts earlier and
more rapid on MRI than the bony contour as visualized on plain radiographs.
Hans Wingstrand and
Roentgenstereophotogrammetry (RSA) has developed into the most exact instrument
to study micromotion in the locomotor system and is used in the development of joint
arthroplasties in the knee, hip and shoulder joints as well as in fracture surgery,
rheuma surgery, plastic surgery and in stereotactic surgery. The prerequisite in
RSA is however the peroperative implantation of 0,8 mm tantalum ball indicators
in the skeleton. Thus the method can be used only in limited prospective studies.
The purpose of this project is to evaluate and further develop a promising non-invasive
method, "Einbild R?tgen Analyse" (EBRA) originally developed at the Orthopaedic
Department, University of Innsbruck.
By developing EBRA into a clinically useful and cost/efficient method for the
study of acetabular cup migration and loosening, a non-invasive method with acceptable
precision for larger retrospective as well as prospective studies on hip joint endoprosthesis
loosening is now available. Four non-invasive methods; EBRA, Sulzer, Wetherell and
Sutherland were compared with RSA; EBRA proved to be the only non-invasive method
with acceptable precision. EBRA was used to study cup wear, migration and cup deformation
in total hip artrhoplasties.
In another project, the biomechanics of the hip joint capsule and its influence
on clinical symptoms, radiological findings and subsequent loosening is studied.
Another study concerns the effect of cement particles on surface structure and
wear in the polyethylene cup.
The long term results on a 10-year follow up of the ScanHip arthroplasty concerning
revision rate and clnical and radiographic data are studied.
Inaugurated in May, 1997, the biomechanics laboratory combines Ph.D.-students
from both the technical and medical faculties, involved in an array of different
research programs. The unit is constituted by 1) an Instron laboratory, 2) an RSA-laboratory
and office space for about a dozen researchers / engineers. The Swedish Knee Arthroplasty
project is also located in these localities. Additionally, a 20-person training
facility (work shop) for surgical interventions forms a part of the unit. The training
facility is supplied with tools and power machines for operations on bone such as
insertion of prostheses, fixation of fractures, arthroscopy phantoms, etc. The unit
is connected to the orthopedic operating theaters by a video-loop and two-way communication
and has comprehensive AV-equipment. In immediate geographical proximity to the biomechanics
unit is the Orthopedic Technical Center for prosthetics and orthotics situated.
Here a comprehensive system for gait analysis -VICON - is installed, which represents
a powerful addition to the unit's ability to analyze functional biomechanics
- The Instron laboratory is built around an Instron 8511, 15kN tension / torsion
testing machine supplied with the MAX software for data retrieval and wave-form
generation. The room is lead shielded for simultaneous RSA investigations. Presently
the Instron is being used in connection with research programs on endoprosthetic
fixation, bone cement, ligament and fracture fixation etc.
- Roentgen stereophotogrammetric analysis (RSA) was developed in Lund by the
late G?an Selvik. The method involves perioperative marking of objects of interest
such as endoprostheses, fracture fragments, ligament insertions. Subsequent
radiographs of the patient and a calibration object are digitized using precision
hard-ware (precision < 10?m) and 2-D coordinates are processed to arrive at
a comprehensive description of motion using Euler rigid body kinematics. The
accuracy of RSA has been determined to about one order of magnitude better than
conventional radiography. The laboratory is equipped with two complete RSA units
using both UmRSA (Unicum, Ume? and WinRSA (Tilly Medical, Lund) software. Presently,
radiography in Sweden is rapidly converting to digital technology and PACS for
data storage. Consequently the unit is involved in converting to handling digital
image data and automation of the digitizing process. The methods is extensively
used in a number of application in the department of Orthopedics, see further
this report e.g. endoprosthetic fixation, lumbar pain and sciatica and optimized
biomaterials for tissue reconstruction.
- Work-station Silicon Graphics equipped with FEM soft ware (Marc) offers
the possibility for analytical work using FEM-models. Presently used to model
implants in the hip and the knee to study interface behavior, fluid flow etc.
Also used to model animal implants for validation purposes.
of Orthopaedics, Lund University Hospital, 221 85 Lund, Sweden
+46-46-171510 Fax: +46-46-130732 Email: email@example.com