The Surgical Management of Pathological Fractures of the Humerus

J. Rush

Introduction

In recent years it has become increasingly common to treat pathological fractures of the humerus by opera- tion. Previously most patients were treated by immo- bilisation of the arm in a sling with or without a simple external splint. In general this conservative approach was very unsatisfactory; the patients continued to have troublesome pain and even if bed-ridden it was difficult to move even a limited amount in comfort. Union of the fracture was slow and uncertain.

Ten per cent of bony metastases occur in the humerus so that the problem of pathological fracture or imminent fracture in this bone is quite common.

The surgical treatment of these fractures depends very much on the level of the lesion. An important consideration is that most of these patients will require deep X-ray therapy immediately post-operatively so that achievement of fracture stability and of primary wound healing is very important.

Before operation the patient should be assessed carefully to confirm the diagnosis, to define the precise anatomy of the metastatic lesion and to document the presence of other metastatic deposits. In general this requires plain high-quality X-rays and isotope bone scan. C.T. scan of the lesion can be very helpful to define its full extent. On occasions a solitary secondary deposit is seen from renal carcinoma.

Proximal humerus

Rarely there can be metastatic deposits in the head of the humerus with or without a fracture but often with a lot of pain. If the lesion is confined to the bone and the shaft of the humerus is not involved the head of

Jonathan Rush, Senior Orthopaedic Surgeon, St. Vincent’s Hospital, Melbourne.

the humerus can be removed and a humeral head prosthesis of the Neer type inserted ie: a partial replacement arthroplasty (Fig. 1).

If the tumour is more laterally placed and there is a normal head of humerus it may be possible to excise the tumour, fill the defect with cement and then apply a short right-angled paediatric blade plate, as de- scribed by Harrington. l

Sometimes a patient presents with a solitary metastatic lesion in the upper end of the humerus either in the head or surgical neck and serious consideration should be given to wide resection of the upper third of the humerus. Replacement can be achieved by insertion of either a homograft or a tumour resection prosthesis (eg the Huckstep shoulder prosthesis or the Robert Mathy’s iso’elastic arm prosthesis Fig. 2).

Fig. l-Partial Replacement Arthroplasty

106

THE SURGICAL MANAGEMENT OF PATHOLOGICAL FRACTURES OF THE HCMERUS 107

Fig. Z-Tumour Resection prosthesis

Humeral shaft fractures

Some patients present with a large painful secondary deposit in the shaft of the humerus without fracture.

This situation can be controlled by using an intrame- dullary nail (either a Kuntscher or Pohl nail) inserted

from either the upper or lower end of the humerus.?

Following operation deep X-ray therapy can be

administered almost immediately. Such a closed intramedullary nailing technique is

also satisfactory in the management of a true patholog-

ical fracture but only if satisfactory reaming can be performed; that is, it is necessary to be able to ream

so that the largest possible nail can engage on sound

cortical bone both proximal and distal to the lesion. If the lesion is distal to the mid-shaft then the nail

should be inserted from above entering the bone through the greater tuberosity (Fig. 3). If the fracture

is proximal to the midshaft (and this is the common

situation) then the nail is best inserted from below

using a posterior approach and entering the bone just proximal to the olecranon fossa2+3 (Fig. 4).

On occasions this relatively simple closed technique

is not satisfactory particularly if there is a fracture through a large lesion and there is a lot of cortical bone

destruction. In this situation it is difficult to obtain

satisfactory rotational control with a simple intrame- dullary nail and it may be necessary to open the fracture, curette out the tumour, insert an intramedul- lary nail and pack the curetted area with bone cement.’ If there is cortical bone above and below the lesion of adequate quality the fracture may be fixed by a large compression type plate. These procedures however mean subjecting the patient, who may be debilitated, to an extensive and prolonged operation; it may be wiser to carry out the lesser procedure of closed intramedullary nailing.

Fig. 3-lntramedullary nail--inserted from above

‘To address this difficult problem of an extensive

destructive lesion of the shaft of the humerus secondary

to metastatic disease or haematological malignancy has been demonstrated4 a modular titanium segmental

defect prosthesis (a two component, bistemmed conically coupled device (Fig. 5)). This device is

biomechanically stronger than a Rush pin or a dynamic

compression plate augmented with methyl methacry- late. A similar diaphyseal prothesis is also available

(Robert Mathys Co).

A recently introduced intramedullary locking nail

(Fig. 6) has helped to overcome the problems of

rotational instability after the intramedullary fixation

Fig. 4-lntramedullary nail-inserted from below

___- _____ ___ __ -_-_ _______

108 CURRENT ORTHOPAEDICS-HOW DO IT

Fig. 5-Compression plate and cement or Segmental Defect prosthesis.

of these difficult fractures5 The nail, however, can only be introduced from above via the greater tuberosity. It has two screws to lock the upper end and a distal ‘spreading’ screw which opens up the lower end of the nail to achieve distal locking. It can therefore be used in most midshaft pathological fractures using a closed technique and yet rotational control is achieved by proximal and distal locking. There remains a need for development of locking humeral nail that can be inserted from below.

Fig. 7-Supracondylar fracture-Rush pins and cement,

-

Fig. 6-Seidel Humeral Locking nail.

Distal humerus

Finally pathological fractures may occur with lesions at the very distal end of the shaft of the humerus and these cannot be treated by the usual intramedullary nails or by plating. Internal fixation is achieved by the introduction of small Rush pins or large Kirschner wires through both the medial and lateral epicondyles; the wires pass subsequently across the fracture into the shaft of the humerus. This can be a difficult technical procedure and on occasions it is necessary to open the fracture through a posterior midline muscle splitting incision. The tumour is curetted out and the pins passed across the fracture from below after which the defect is filled with bone cement (Fig. 7).

In conclusion; in our unit it has been found most effective to fix internally most pathological fractures of the humerus and, in general it is more prudent to use closed intramedullary techniques.

References

1. Harrington K D 1988 Orthopaedic management of metastatic bone disease. St Louis: C V Mosby Co chapter 10 ~255

2. Fischer S, Hempel D 1982 Intramedullary nailing. New York: Georg Thilme Verlag Stuttgart p33

3. Rush J 1987 Closed nailing of the humerus-From down under. Aust NZ J Surg 57 : 723-125

4. Chin H-C, Frassica F J, Hein T J, Shivers T C, Pritchard D J, Sim F H, Chao E Y S 1989 Metastatic diaphyseal fractures of the shaft of the humerus. Clin Orthop 248 : 23 1

5. Seidel H 1989 Humeral locking nail: A preliminary report. Orthop 12 : 219-226