Wounds of the fifth class were the most dangerous, but the danger was entirely a secondary one, dependent on the occurrence of infection. These injuries were liable to be accompanied by the presence of extensive irregular wounds of the soft parts, in which suppuration was frequent, and the suppuration of the joint frequently meant subsequent amputation, if not a worse result.
Course and symptoms of wounds of the joints.—The immediate result of any perforation of a joint was the development of intra-articular effusion. This consisted of synovial fluid admixed with a varying proportion of blood. The degree of synovitis was apt to vary with the amount of force expended in the production of the injury; for this reason both high velocity and irregular impact were of importance in this relation.
The constant feature, however, depended on the effusion of blood; this was not rapid, or, as a rule, very abundant, but tended to increase during the first twenty-four hours. It resulted in a swelling of the joint, which possessed some peculiar features. At first elastic and resilient, it slowly decreased in volume with the assumption of a soft doughy character on palpation. In the case of the knee, where readily palpated, it very much resembled a tubercular synovial membrane, except for its extreme regularity of surface; still more closely the condition noted in a hæmophilic knee of some duration. Absorption took place with some rapidity, and except for slight thickening, the joints might appear almost normal, in a period of from two to four weeks. With the development of the effusion there was local rise in temperature of the surface, and in a considerable number of the cases a general rise of temperature.
This latter was sometimes very marked, as in the case of all the other traumatic blood effusions, but not quite so regular in occurrence. It was important, as I have seen it give rise to the suspicion of suppuration, when tapping resulted in nothing more than the evacuation of turbid synovia mixed with blood. Pain was rarely a prominent symptom in consequence of the generally moderate degree of distension.
As a rule, these injuries were characterised by the small tendency to the development of adhesions; but this in great part depended on the care expended on their treatment. If kept too long quiet, either from necessity when the effusion was followed by much thickening, or when the external wound was large and so situated as to be harmfully influenced by movement, or in the ordinary course of treatment, troublesome stiffness, even amounting to firm anchylosis, sometimes followed. I saw several such cases, some of the most confirmed being wounds of the knee-joint complicated by injury to the popliteal vessels or nerves. The latter complication I saw altogether six times, but only once with a thoroughly bad knee, and in this case the injury had affected both the vessels and the internal popliteal nerve. The joint in that case was straightened out by continuous extension by Major Lougheed, when it came under his charge some six weeks after the primary injury, but I hear has again relapsed, and the popliteal paralysis is not much improved.
The small tendency to formation of adhesions in uncomplicated cases probably depended on the coagulation of a layer of blood over the whole internal lining of the joint. This kept the synovial surfaces apart at the lines of reflection of the membrane, and, given sufficiently active treatment, mobility was restored before any firm union could take place.
The primary escape of synovial fluid was rarely observed, as the wounds of the soft parts were too small and valvular to permit of it. Synovia in some abundance, mixed with pus, sometimes escaped in considerable quantity when infection had opened up the tracks.
Primary suppuration in any joint as a result of small and direct wounds was very rare. I observed it only on one occasion. On the other hand, a considerable number of cases in which secondary suppuration occurred came under my notice. In some of these the suppuration was secondary to comminuted fractures of the shaft of the tibia, in which the articular extremity was implicated. These offered no special peculiarity. In others infection of the joint was secondary to infection and suppuration in the deep part of long oblique wound tracks, and these were of sufficient interest to warrant the insertion of two illustrative cases.
(43) In a man wounded at Paardeberg the bullet entered the leg to the inner side of the crest of the tibia, about 3 inches below the tubercle; thence it coursed upwards to emerge about 2 inches above the cleft of the knee-joint on the outer side. Regulation dressings were applied, and a week later the man arrived at the Base, with little apparent mischief in the knee-joint. He was placed in bed and warned against movement; on the second day, however, he got up and walked to the latrine. When bending his knee to sit down he was seized with agonising pain in the joint, and had to call out for help; he was then carried back to bed in a more or less collapsed condition. The knee commenced to swell; there was rise of temperature and great pain, together with extreme restlessness. I was asked to see him two days later, and after a consultation, Major Burton, R.A.M.C., freely incised the knee-joint bi-laterally. One opening was closed, the second plugged for drainage, as there was a large quantity of pus. No improvement followed, and a week later Major Burton amputated through the thigh. An attack of secondary hæmorrhage a few days later, combined with the degree of septic infection, ended the man's life. On examination of the joint, a groove forming three-fourths of a tunnel was found in the external tuberosity of the tibia, leading into the knee-joint beneath the external semilunar cartilage. The bullet had then passed upwards over the outer border of the cartilage, bruised the margin of the external condyle of the femur in such a manner as to depress the outer compact layer, and finally escaped from the joint near the upper reflection of the synovial membrane. The synovial membrane was granular in appearance and reddened, but there was no suppuration outside the confines of the joint, except in a cavity corresponding to 2 inches of the track before it actually perforated the tibia. A localised abscess had evidently formed here and been diffused into the joint by the movement of flexion already described.
(44) A man wounded during General Hamilton's advance on Heilbron was struck on the outer aspect of the heel. An oval opening of some size led down to a track in the os calcis; the bullet was retained. The foot was dressed, and put up later in a plaster-of-Paris splint. On the tenth day the splint was removed to see to the wound, which looked satisfactory and was re-dressed.