Jørgen Reimers

Biographical Timeline

• Born February 6, 1931 in Copenhagen, Denmark.
• 1969 – Working in the Outpatient Department for Handicapped Children at Rigshospitalet, Copenhagen, under paediatric neurologist Preben Plum.
• 1970 – Undertook an extended study visit to Sheffield with paediatric orthopaedic surgeon W. J. W. Sharrard, whose work on muscle imbalance and deforming forces strongly influenced Reimers’ approach to neuromuscular orthopaedics.
• 1971 – Studied in Toronto with Robert Bruce Salter (1924-2010), Norris Carroll, John Hall and Mercer Rang. Reimers credited this visit with reinforcing a dynamic concept of hip stability that was “not generally accepted at that time.”
• 1973 – Published Static and dynamic problems in spastic cerebral palsy, analysing the relationship between lower-limb muscle groups, sagittal balance and deformity in cerebral palsy. 1974 – Published a prospective study of 60 patients with cerebral palsy and hamstring contracture, comparing three operative methods. He favoured proximal hamstring lengthening in selected patients over distal lengthening and the Egger procedure.
• 1975–1978 – Worked in the Department of Orthopaedic Surgery U, Rigshospitalet, under Professor C. C. Arnoldi. His major study of childhood hip stability was completed during this appointment.
• 1980 – Published his 100-page thesis The stability of the hip in children. A radiological study of the results of muscle surgery in cerebral palsy. Defined migration percentage (MP) as a quantitative measure of lateral migration of the femoral head relative to the acetabulum. Dr.med. at the University of Copenhagen
• 1982 March 13 – One of the 13 founding surgeons of the European Paediatric Orthopaedic Society (EPOS) at Hôpital Bretonneau, Paris.
• 1985 – Published on femoral-head containment following Legg–Calvé–Perthes disease.
• 1987 – Published on the treatment of acquired hip subluxation in cerebral palsy, continuing his work on neuromuscular hip instability.
• 1989 – Elected Vice-President of EPOS at the society’s eighth annual meeting in Helsinki.
• 1991 – Elected fifth President of EPOS, succeeding Henri Bensahel.
• 2000 – Retired from Children’s Orthopaedics at the National Hospital (Rigshospitalet), Copenhagen.
• Died on March 24, 2008 in Copenhagen, aged 77.

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Medical Eponyms

Reimers migration percentage

Reimers migration percentage (MP) is a radiographic measure of lateral displacement of the femoral head relative to the acetabulum, developed by Jørgen Reimers for assessment and serial follow-up of hip instability in children, particularly those with cerebral palsy.

On an AP pelvic radiograph, the width of the femoral head lying lateral to Perkins line is divided by the total horizontal width of the visible femoral head and expressed as a percentage. Hilgenreiner line provides the horizontal pelvic reference from which Perkins line is constructed.

Reimers introduced the measurement in his 1980 monograph The Stability of the Hip in Children. He deliberately chose Perkins line because it provided a direct measure of the position of the femoral head relative to the acetabulum and avoided the difficulty of locating the centre of the femoral head required for the centre-edge angle.

Reimers defined subluxation as MP ≥33% and dislocation as MP 100%. He also established age-related observations from 355 comparison hips: in children younger than four years the visible head was usually completely medial to Perkins line, while a small amount of lateral projection became increasingly common in older children.

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Key Medical Contributions

Quantification of hip migration in cerebral palsy

Reimers transformed the assessment of the spastic hip from a largely descriptive judgement into a serial quantitative measurement. Migration percentage allowed lateral displacement to be recorded repeatedly over time and provided a common outcome measure for evaluating progression and treatment. His work demonstrated that hip subluxation in cerebral palsy was commonly acquired and progressive, rather than simply a fixed congenital abnormality.

This has probably become his most enduring contribution. Modern cerebral-palsy hip surveillance programmes still regard MP as a central quantitative measure of hip displacement. A 2023 study described it as the “keystone for hip screening” and demonstrated that it can now be measured reliably by multidisciplinary clinicians using digital tools.

Muscle imbalance and the spastic hip

Reimers’ work was based on the concept that the developing hip is dynamically influenced by surrounding musculature, particularly the balance between hip abductors and adductors. His 1980 thesis followed children longitudinally and used changes in MP to examine the effects of adductor release and other soft-tissue procedures.

He found that spontaneous outward migration was common in untreated cerebral-palsy hips and that adductor surgery could arrest or reverse migration in a proportion of cases. His analyses also suggested that age and preoperative degree of migration influenced the response to treatment.

Radiographic methodology and positioning

Reimers also examined potential sources of error in measuring femoral-head coverage. He investigated hip rotation and concluded that neutral rotation was clinically suitable for standard AP radiography, while recognising that abduction and adduction alter migration percentage.

His subsequent 1981 work with Viktor Bialik further examined the effect of femoral rotation on apparent radiographic coverage. Modern studies have continued to investigate measurement error and reproducibility.

Paediatric hip disease beyond cerebral palsy

Reimers applied similar principles of femoral-head containment to Legg–Calvé–Perthes disease, demonstrating that early lateral migration could subsequently improve and that long-term coverage could approach that of the contralateral normal hip.

His earlier work also included the biomechanics of spastic cerebral palsy, hamstring contracture and operative treatment, while later studies examined foot deformity and triceps surae shortening in children.

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Major Publications

• Reimers J. Static and dynamic problems in spastic cerebral palsy. J Bone Joint Surg Br. 1973 Nov;55(4):822-7. 
• Reimers J. Contracture of the hamstrings in spastic cerebral palsy. A study of three methods of operative correction. J Bone Joint Surg Br. 1974 Feb;56(1):102-9.
• Reimers J. Stabiliteten af børns hofteled bedømt ved ét røntgenfoto [Stability of the hip-joint in children assessed by X-ray photograph]. Ugeskr Laeger. 1979 Jan 22;141(4):231-3.
• Reimers J. The stability of the hip in children. A radiological study of the results of muscle surgery in cerebral palsy. Acta Orthop Scand Suppl. 1980;184:1-100. 
• Reimers J, Bialik V. Influence of femoral rotation on the radiological coverage of the femoral head in children. Pediatr Radiol. 1981;10(4):215-8.
• Reimers J. Incidence of full containment of the femoral head after Legg-Calvé-Perthes disease and in the “normal” hip. J Pediatr Orthop. 1985 Mar-Apr;5(2):199-201.
• Reimers J. Treatment of acquired hip subluxation in cerebral palsy. J Pediatr Orthop. 1987 Sep-Oct;7(5):605-6.
• Reimers J, Pedersen B, Brodersen A. Foot deformity and the length of the triceps surae in Danish children between 3 and 17 years old. J Pediatr Orthop B. 1995;4(1):71-3.

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References

Biography

• Jørgen REIMERS. EPOS

Eponymous terms