Injury, Int. J. Care Injured 32 (2001) 689–691

Interface pressure produced by the traction post on a standardorthopaedic table

Claire J. Topliss *, J.M. WebbDepartment of Trauma and Orthopaedics, Southmead Hospital, North Bristol NHS Trust, Westbury on Trym, Bristol BS10, UK

Accepted 27 March 2001

Abstract

Lower limb traction is applied with counter traction in the groin. The resultant tissue pressures can be high and may result inskin necrosis or nerve palsies.

Volunteers were positioned on a fracture table and traction applied to the left leg. Perineal contact pressures were measuredusing pressure transducers connected to a laptop computer. Pressure readings and pain scores were recorded with different typesof padding, whilst the leg was repositioned.

Maximal pressures exceeded the 70 mmHg limit known to cause tissue damage. Larger (10 cm) padding devices significantlyreduced the pressures. When employing the perineal traction post, care should be taken to pad this carefully to avoid the sequelaeof high tissue pressure. © 2001 Elsevier Science Ltd. All rights reserved.

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1. Introduction

Orthopaedic procedures commonly require applica-tion of lower limb traction, with counter-traction ap-plied at a post placed against the groin. Review ofthe literature reports: perineal sloughing [1]; pressuresores [2] and pudendal nerve palsies [3–6].

Tissue pressures of 70 mmHg applied for 2h havebeen shown to result in microscopic tissue change [7],whilst pressures of 1.4 kg/cm2 for 90 minutes pro-duced severe or complete nerve conduction block [3].

In this observational study we identified the inter-face pressures exerted by the perineal traction post.

2. Methods and materials

Nine healthy volunteers were positioned supine onan orthopaedic traction table, with the right lowerlimb supported in flexion and abduction (Fig. 1a).

The left lower limb was positioned in neutral and hadlongitudinal traction applied through the boot (Fig.1b). Previous work on traction force profiles in eightpatients [8] identified an average traction force of 345N and a mean maximum force of 460 N throughoutthe course of an operation. To approximate theseforces we used a standard load: a weight of 40 kg(392 N).

Pressures were measured using a calibrated pressurepad consisting of individual, inch-square pressure cells(Force Sensing Array, Vista Medical Limited,Canada). The pad was placed around the tractionpost next to the groin and connected to a laptopcomputer. Five different types of padding were usedaround the standard 3 cm diameter traction post:gamgee (cotton wool gauze); small gel pad; 10 cm gelbolster; soft 10 cm foam roll; hard 10 cm foam roll.With each type of padding, the leg was positioned inneutral, internal rotation, external rotation and ad-duction. Pressure readings and pain scores wererecorded with each manoeuvre. The measurementswere recorded at one point in time, once the pressurereadings had stabilised. Data were entered onto aspreadsheet (Microsoft Excel) and analysed with astatistics package (SPSS).

* Corresponding author. Present address: University Departmentof Orthopaedics, Level 5, Bristol Royal Infirmary, Bristol BS2 8HW,UK..

E-mail address: Toplisscj@hotmail.com (C.J. Topliss).

0020-1383/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved.PII: S 0 0 2 0 -1383 (01 )00043 -2

C.J. Topliss, J.M. Webb / Injury, Int. J. Care Injured 32 (2001) 689–691690

Fig. 1a. The position of the limbs during the study. Fig. 2. Graph showing the average area over which pressure wasexerted.

Fig. 3. Graph showing average pressure exerted over the area foreach padding type, at the point when the pressure readings hadstabilised. Range depicted by the vertical line and the mean by thethick horizontal line.

Fig. 1b. The position of the limbs during the study

3. Results

In the small-diameter padding group, the area overwhich pressure was exerted was less (Fig. 2), and theaverage and maximum pressures were higher (Figs. 3and 4). In all subjects the maximum pressure readingswere observed with the gamgee wrap (Fig. 4). Allsubjects noted their highest pain score here. Peak pres-sures of 100 mmHg were observed over the ischialtuberosity and adductor tendons. The most comfort-able devices, and those with significantly lower pres-sures (P�0.01, Mann Whitney), were those with alarger diameter (10 cm soft foam roll, 10 cm hard foamroll and 10 cm gel bolster). In the large diameterpadding group, there was no significant difference be-tween the three padding types. Of the different posi-tions, adduction resulted in highest pressures and painscores though this was not significant.

4. Discussion

The highest measured pressures exceeded the 70mmHg limit known to cause tissue damage. We havedemonstrated that these pressures can be reduced withalteration of the padding around the traction post. Thetype of padding is not critical but the diameter shouldbe at least 10 cm. In all procedures, the time spent withthe high traction loads applied, with the leg in theadducted position, should be kept to a minimum.

Acknowledgements

The authors thank Mr Guy Rooker, Consultant Or-thopaedic Surgeon and Mr Andrew Houston, SeniorOrthopaedic Nurse (Cheltenham General Hospital), the

Fig. 4. Graph showing maximum pressures exerted for each paddingtype when the pressure readings had stabilised. The format is thesame as Fig. 3.

C.J. Topliss, J.M. Webb / Injury, Int. J. Care Injured 32 (2001) 689–691 691

staff of the Wheelchair Assessment Units (CheltenhamGeneral Hospital and Avon Orthopaedic Centre, Bris-tol), and finally the volunteers who kindly gave theirtime in this sometimes painful project.

References

[1] Callanan I, Choudhry V, Smith H. Perineal sloughing as a resultof pressure necrosis from the traction post during prolongedbilateral femoral nailing. Injury 1994;25:472.

[2] Shaw J, Hughes A. Pressure sores and the orthopaedic traction-yetanother skin area to protect. NATNews 1985;Sept:34–6.

[3] Lindenbaum SD, Fleming LL, Smith DW. Pudendal nerve palsiesassociated with closed intramedullary femoral fixation. J Bone Joint

Surg 1982;64-A:934–8.[4] Hofmann A, Jones RE, Schoenvogel R. Pudendal nerve neuro-

praxia as a result of traction on the fracture table. J Bone Joint Surg1982;64-A:136–8.

[5] France MP, Aurori BF. Pudendal nerve palsy following fracturetable traction. Clin Orthop Relat Res 1992;276:272–6.

[6] Brumback RJ, Ellison S, Molligan H, Molligan DJ, Mahaffey S,Schmidhauser C. Pudendal nerve palsy complicating in-tramedullary nailing of the femur. J Bone Joint Surg 1992;74-A:1450–5.

[7] Kosiak M. Etiology of decubitus ulcers. Arch Phys Med Rehabil1961;Jan:19–29.

[8] Kruger DM, Kayner DC, Hankin FM, Falahee MH, Kaufer H,Matthews LS, Goldstein SA. Traction force profiles associated withthe use of a fracture table: a preliminary report. J Orthop Trauma1990;4:283–6.