BIODEGRADABLE IMPLANTS IN FRACTURE FIXATION: EARLY RESULTS OF TREATMENT OF FRACTURES OF THE ANKLE

1422 many of the subjects expended very little more energy over extended periods when following their customary activity patterns than they did while in the calorimeter. The factorial calculations of daily energy expenditure which have formed the foundation of most national and international recommendations and have therefore had a strong influence in defining accepted nutritional norms are very approximate computations which combine the time spent on various activities with an energy cost assigned to each activity.2O There is clearly scope for large error in these calculations, and estimates of expenditure derived in this way usually exceed observed energy intakes." The validity of factorial estimates of energy expenditure has been challenged21 independently of double-isotope results such as ours, which appearto refute many of the assumptions used in factorial estimates and are more consistent with estimates of energy intake. The DHSS and WHO/FAO recommendations are intended to cover the requirements of all people in a given activity category and, even in the light-activity category, contain an allowance for active recreation considered necessary for the maintenance of optimal cardiovascular and muscular fitness. Many of the subjects in this study did not take part in any active sport, but even if they had spent 0’ 5 h each day in a strenuous sport their TEE/BMR would have risen only by O. 05-0.10 units. Apart from this the subjects covered a fairly wide range of social class and occupation, although none of the occupations involved heavy manual work. The very low expenditures presumably reflect the subjects’ modern lifestyle, in which labour-saving devices, motorised transport, and central heating reduce the need to expend energy to a minimum. We emphasise that we are not advocating such low levels of energy expenditure as optimal for health or suggesting that the recommended requirements should necessarily be reduced. Our data add weight to current efforts to promote sport in an attempt to counteract low-activity patterns, which have associated risks of obesity and coronary heart disease. Although the number of women studied is small and may not be entirely representative of British women, our results show that it is possible to maintain energy balance at much lower levels of intake than has hitherto been acknowledged and suggest that an energy intake equivalent to 1’5times BMR will leave considerable energy available for physical activity. We thank Dr M. Elia for

BIODEGRADABLE IMPLANTS IN FRACTURE FIXATION: EARLY RESULTS OF TREATMENT OF FRACTURES OF THE ANKLE O. BÖSTMAN K. VIHTONEN J. LAIHO M. TAMMINMÄKI

P. ROKKANEN S. VAINIONPÄÄ P. TÖRMÄLÄ J. KILPIKARI

Department of Orthopaedics and Traumatology, Helsinki University Central Hospital; and Laboratory of Polymer and Fibre Technology, Tampere University of Technology, Finland

Biodegradable polylactide-glycolide copolyimplants for fracture fixation were in rabbits. In a prospective clinical and tested developed 44 with a displaced fracture of the ankle were study patients allocated to two groups; one was treated with randomly conventional metallic implants and the other with the biodegradable implants. There were no differences between the two groups in the early results, but the biodegradable fixation method is advantageous because the removal procedure associated with metallic implants is avoided. Summary

mer

INTRODUCTION

BIODEGRADABLE surgical implants offer some definite advantages over metallic ones in fracture fixation. A biodegradable implant initially maintains the stability of the fixation, but as it gradually loses its strength and is digested the stresses are transferred to the healing bone. Thus, the adverse effects on bone of long-term stress protection provided by metallic implants are avoided. Also, use of biodegradable implants abolishes the need to remove the fixation material. In common fractures this is of considerable financial importance. The development of suitable biodegradable implants, however, has proved to be laborious and to our knowledge this is the first report on successful clinical application of biodegradable implants in fracture

fixation. METHODS

The Implants and Pre-clinical Studies

Polylactide-glycolide copolymer (’Polyglactin 910’ I) was chosen implants because of its biological properties as a well-

for the

providing clinical cover for this study.

Correspondence should be addressed to A. M.

P.

DA, van Santen E. Measurement of energy expenditure in humans by doubly-labelled water method. J Appl Physiol 1982; 53: 955-59. Schoeller DA, Webb P. Five-day comparison of the doubly-labelled water method with respiratory gas exchange. Am J Clin Nutr 1984; 40: 153-58. Lifson N, Gordon GB, McClintock R. Measurement of total carbon dioxide production by means of D218O. J Appl Physiol 1955, 7: 704-10. Coward WA, Prentice AM. Isotope method for the measurement of carbon dioxide production in man. Am J Clin Nutr 1985; 43: 659-61. Dallosso HM, James WPT. Whole-body calorimetry studies in adult men I The effect of fat over-feeding on 24 h energy expenditure. Br J Nutr 1984, 52: 49-64. Paul AA, Southgate DAT, McCance and Widdowson’s The composition of foods London HM Stationery Office, 1978. Cunningham JJ. A re-analysis of the factors influencing basal metabolic rate in normal adults. Am J Clin Nutr 1980; 33: 2372-74. Coward WA, Cole TJ, Sawyer MB, Prentice AM, Orr-Ewing AK Breast-milk intake measurement in mixed-fed infants by administration of deuterium oxide to their

10. Schoeller

REFERENCES

11.

1. DHSS. Recommended daily amounts offood energy and nutrients for groups of people in the United Kingdom. Rep Hlth Soc Subjects 15. Department of Health and Social Security. London: HM Stationery Office, 1979. 2. NRC. Recommended dietary allowances. 9th revised edition. Washington DC: National Academy of Sciences, National Research Council, 1980. 3. WHO/FAO. Energy and protein requirements. WHO Tech Rep Ser 522. Geneva: WHO, 1973. 4. Prentice AM. Adaptations to long-term low energy intakes. In: Pollitt E, Amante P, eds. Energy intake and activity. Current topics in nutrition and disease Vol 11. New York: Alan R Liss Inc, 1984: 3-31. 5. Whitehead RG, Paul AA Diet and the pregnant and lactating woman. In: Turner MR, ed. Nutrition and Health, a perspective. London: MTP Press, 1982: 159-68. 6. Butte NF, Garza C, Stuff JE, Smith EO’B, Nichols BL. Effect of maternal diet and body composition on lactational performance. Am J Clin Nutr 1984; 39: 296-306. 7. James WPT, Shetty PS. Metabolic adaptations and energy requirements in developing countries. Hum Nutr: Clin Nutr 1982; 36C: 331-36. 8 Coward WA, Prentice AM, Murgatroyd PR, et al. Measurement of CO2 and water production rates in man using 2H, 18O-labelled H2O; comparison between calorimeter and isotope values. Proc Euro-Nut Workshop on Human Energy Metabolism, Wageningen, 1985: 126-28. 9. Klein PD, James WPT, Wong WW, et al. Calorimetric validation of the doublylabelled water method for determination of energy expenditure in man. Hum Nutr: Clin Nutr 1984; 38C: 95-106.

12

13. 14. 15 16.

17.

mothers. Hum Nutr: Clin Nutr 1982; 36C: 141-48 18.

19

Calloway DH, Spector H. Nitrogen balance as related to calorie and protein intake in active young men. Am J Clin Nutr 1954; 2: 405-11. Ravussin E, Burnand B, Schutz Y, Jequier E Twenty-four hour energy expenditure and resting metabolic rate in obese, moderately obese, and control subjects Am J

Clin Nutr 1982; 35: 566-73. 20. Passmore R, Durnin JVGA. Energy, Work and Leisure London Heinemann Educational Books Ltd, 1967. 21. Durnm JVGA. Some problems in assessing the role of physical activity in the maintenance of energy balance In. Pollitt E, Amante P, eds. Energy intake and activity. Current topics in nutrition and disease Vol 11 New York: Alan R Liss Inc 1984: 101-13.

1423

Fig 1-Anteroposterior radiograph showing a displaced bimalleolar fracture.

’

established absorbable suture material, the ’Vicryl’ suture. The implants were made by moulding polylactide-glycolide copolymer matrix and fibres of the same composition as a reinforcing medium. This material was formed in cylinder-shaped rods 3-22 mm or 4 -5mm in diameter and 50 mm or 70 mm in length. In a pre-clinical study on rabbits an osteotomy in the cancellous bone of the distal femur was fixed with a polyglycolide rod and sutures without any external support. Healing of the osteotomy within 6 weeks was demonstrated by means of radiographic, histological, microradiographic, and oxytetracycline labelling

Fig 2-The fracture treated by open reduction and internal fixation with biodegradable material seen united at 6 weeks.

Exact union of the fracture in the reduced position was successful in all but 2 patients: 1 patient in each group slipped during the first 2 postoperative weeks, and the fixation was partially dislodged. The secondary displacement of the fragments was 1’ 5 mm and reoperation was deemed unnecessary. The mean duration of sick leave was 62 days in the metallicimplant group and 57 days in the biodegradable-fixation group.

studies.

Patients 44 consecutive adult patients with displaced malleolar fractures of the ankle and admitted to the department of orthopaedics and traumatology, Helsinki University Central Hospital, between November, 1984, and March, 1985, entered the study. Patients with an associated fracture of the posterior triangle who needed reduction and fixation or rupture of the distal tibiofibular syndesmosis and transfixation of the fibula to the tibia were not included. 30 patients had fractures of the lateral malleolus with or without rupture of the deltoid ligament, and 14 had bimalleolar fractures. All had a displacement of 2 mm or more of the malleolar fragments or of the talus (fig 1) and needed open reduction and internal fixation.2 The patients were randomly allocated to two treatment groups; one (22 patients) was treated with metallic implants and the other (22 patients) with the biodegradable implants (figs 2 and 3). The management of the two groups was otherwise identical. A padded below-the-knee plaster cast was applied immediately after the wounds were closed in the operating theatre. The length of the hospital stay varied from 3 to 5 days. Full weight-bearing was allowed after 4 weeks and the plaster was discarded at 6 weeks. RESULTS

The

duration of the operation was 34 min in the group and 42 min in the biodegradablefixation group. An anatomical reduction of the fragments was achieved in all but 1 bimalleolar fracture in the mean

metallic-implant

Fig 3-An

biodegradable-implant group.

The biodegradable rods (1) are placed within the cancellous bone in drill channels across the fracture surfaces. A figure-of-eight polylactide-glycolide I suture (2) reinforces the fixation.’

artist’s view of the fixation

technique.

1424 DISCUSSION

The Kit

There was no difference in outcome between two groups of patients with displaced fractures of the ankle treated with metallic implants and biodegradable implants, respectively. These early results will, however, be influenced by the fact that biodegradable material does not need to be surgically removed.

routinely This

We are now using in our department.

biodegradable implants

study was supported by The Academy of Finland.

Correspondence should be addressed to P. R., Toolo Hospital, Topelmksenkatu 5, SF-00260 Helsinki, Finland. REFERENCES 1.

Belg patent no 900513 and patent applications in several countries. FA, Gail M, Pee D, Fitzpatrick T, Van Herpe LB. Quantitative criteria for prediction of the results after displaced fracture of the ankle. J Bone Jt Surg 1983;

2. Pettrone

65A: 667-77. 3. Müller ME, Allgöwer M, Schneider R, Willenegger H. Manual of internal fixation. Technique recommended by the AO-group. New York: Springer, 1979: 282-99.

I have designed a portable kit for emergency tracheal intubation. Tracheal tubes are cut to size, fitted with standard 15 mm connectors, and stored in a suitable box (in this case an old pacemaker box) (see figure). The two sides of the box, one for use in children and the other for adults, close together to form a portable case 19 cm x 26 cm. The range of tracheal tubes illustrated should be adequate for most situations. The three cuffed tubes are for the resuscitation of a teenager, an average adult female, and an average adult male. For say, acute anaphylaxis, in which extreme narrowing of the upper airway may be a feature, a plain tube is included on the adult side of the kit. The additional space in the case may be used for other resuscitational aids. The mouldings of the case have been designed to ensure that the tracheal tubes retain their natural curvature in storage and also provide templates for replacement tubes. The sizes for these were based on the table by Dunnill and Crawley,6 which reflects practice in the UK. A disadvantage of the kit is that the tubes are not sterile, but this is a small price to pay for the convenience to the user and the overall safety of the patient. I thank Miss H. Ashford for typing the manuscript and the Audiovisual Department, University Medical School, Newcastle upon Tyne, for preparing the photographs. Correspondence should be addressed to 1. D. C.

Methods and Devices TRACHEAL INTUBATION KIT FOR RESUSCITATION

REFERENCES

I. D. CONACHER

Department of Cardiothoracic Anaesthesia, Freeman Hospital, High Heaton, Newcastle upon Tyne TRACHEAL intubation is often needed for the isolation and

protection of the airway of patients requiring surgery, artificial ventilation, or cardiopulmonary resuscitation. The

of a tube that is

long may result in endobronchial intubation, possibly leading complications such as hypoxaemia, and gradual detachment of a tube from the trachea is a danger of the use

too

1. Hahn RW, Martin JJ, Lillie JC. Vocal cord paralysis with endotracheal intubation Arch Otolaryngol 1970; 92: 226. 2. Ellis PD, Pallister WK. Recurrent laryngeal nerve palsy and endotracheal intubation. J Laryngol Otol 1975; 89: 823-26. 3. Welsh BE, Conn AW. Jig for measuring endotracheal tube lengths. Can Anaesth Soc J 1970; 17: 187-88. 4. Saha AK. The estimation of the correct length of oral endotracheal tubes in adults Anaesthesia 1977; 32: 919-20. 5. Allen CTB. Apparatus for emergency intubation in laryngeal obstruction Anaesthesia 1976; 31: 263-67. 6. Dunnill RP, Crawley BE. Clinical and resuscitative data. Oxford: Blackwell Scientific Publications, 1977: 21.

to

insertion of tubes that

are too

short. Vocal cord

damage

and

laryngeal nerve injurydue, possibly, to the effects of incorrect siting of inflated cuffs on tracheal tubes have also been reported. Regular practitioners of tracheal intubation tend to cut tubes of appropriate internal diameter to a safe length before insertion. A jig for measuring tube lengths in paediatric practice has been described,3and there are tables which aid the selection of optimum lengths,4 but none of these is likely to be readily available in an emergency situation. With the exception of kits for specialist paid to the presentation of tracheal tubes.

needs5

little attention is

Portable kit for tracheal intubation. The 7 tubes for paediatric use (right) range from 2 - 5 mm to 6 - 0 mm (internal diameter). The tubes for use in adults (left) include a 6 -5mm plain tube and 3

cuffed tubes with internal diameters of 7-0 0 mm, 8-5 5 mm, and 9-0 0 mm.

Reviews of Books Free Radicals in

Biology and Medicine

Barry Halliwell, King’s College, London, and John M. C. Guttendge, National Institute for Biological Standards and Control, London. Oxford: Oxford University Press. 1985. Pp 346. 30. IN the past decade Lancet readers have been intermittently nudged about the existence of free radicals through reviews (eg, Free radical oxidation and antioxidants, 1978); editorials (eg, Pregnancy and the arachidonic acid cascade, 1982); preliminary communications (eg, Lipid peroxidation products in bile in patients with pancreatic disease, 1983); hypotheses (eg, A radical interpretation of immunity to malaria parasites, 1983); and letters to the editor (eg, Metronidazole and tissue zinc/iron ratio in cancer therapy, 1976). The variety and scope of these articles should at least have impressed upon us the ubiquitous nature, protean effects, and potential biological importance of free radicals. Yet, I suspect that most clinicians gloss over these unorthodox writings, quickly turning to more familiar and comfortable territory. This book, the brainchild of two scientists who are recognised authorities in the free radical field, is timely, for there is little doubt that the evidence for the involvement of free radicals in human diseases will rise exponentially in the next decade. Clinicians can no longer ignore the topic: getting to grips with basic chemistry, and free radical chemistry at that, is a painful process but the authors have achieved their aim-"to lead the reader as painlessly as possible" into an area whose importance has for long been appreciated by food and industrial chemists. For medical readers the appendix of 15 pages on atomic structure and bonding provides an invaluable starting point. However, the resolve of even the most