These procedures may be carried out at the same time as the sequestrum is removed, or after an interval.  In all of them, asepsis is essential for success.

The deformities resulting from osteomyelitis are more marked the earlier in life the disease occurs.  Even under favourable conditions, and with the continuous effort at reconstruction of the bone by Nature’s method, the return to normal is often far from perfect, and there usually remains a variable amount of hyperostosis and sclerosis and sometimes curving of the bone.  Under less favourable conditions, the late results of osteomyelitis may be more serious. Shortening is not uncommon from interference with growth at the ossifying junction. Exaggerated growth in the length of a bone is rare, and has been observed chiefly in the bones of the leg.  Where there are two parallel bones—­as in the leg, for example—­the growth of the diseased bone may be impaired, and the other continuing its normal growth becomes disproportionately long; less frequently the growth of the diseased bone is exaggerated, and it becomes the longer of the two.  In either case, the longer bone becomes curved.  An obliquity of the bone may result when one half of the epiphysial cartilage is destroyed and the other half continues to form bone, giving rise to such deformities as knock-knee and club-hand.

Deformity may also result from vicious union of a pathological fracture, permanent displacement of an epiphysis, contracture, ankylosis, or dislocation of the adjacent joint.

#Relapsing Osteomyelitis.#—­As the term indicates, the various forms of relapsing osteomyelitis date back to an antecedent attack, and their occurrence depends on the capacity of staphylococci to lie latent in the marrow.

Relapse may take place within a few months of the original attack, or not for many years.  Cases are sometimes met with in which relapses recur at regular intervals for several years, the tendency, however, being for the attacks to become milder as the virulence of the organisms becomes more and more attenuated.

Clinical Features.—­Osteomyelitis in a patient over twenty-five is nearly always of the relapsing variety.  In some cases the bone becomes enlarged, with pain and tenderness on pressure; in others there are the usual phenomena which attend suppuration, but the pus is slow in coming to the surface, and the constitutional symptoms are slight.  The pus may escape by new channels, or one of the old sinuses may re-open.  Radiograms usually furnish useful information as to the condition of the bone, both as it is altered by the original attack and by the changes that attend the relapse of the infective process.

Treatment.—­In cases of thickening of the bone with persistent and severe pain, if relief is not afforded by the repeated application of blisters, the thickened periosteum should be incised, and the bone opened up with the chisel or trephine.  In cases attended with suppuration, the swelling is incised and drained, and if there is a sequestrum, it must be removed.