We investigated changes in the axial alignment of the ipsilateral
hip and knee after total hip arthroplasty (THA). We reviewed 152 patients undergoing primary THA (163 hips; 22
hips in men, 141 hips in women) without a pre-operative flexion
contracture. The mean age was 64 years (30 to 88). The diagnosis
was osteoarthritis (OA) in 151 hips (primary in 18 hips, and secondary
to dysplasia in 133) and non-OA in 12 hips. A posterolateral approach
with repair of the external rotators was used in 134 hips and an
anterior approach in 29 hips. We measured changes in leg length
and offset on radiographs, and femoral anteversion, internal rotation
of the hip and lateral patellar tilt on CT scans, pre- and post-operatively. Aims
Patients and Methods
The aim of this study was to determine whether chilled irrigation
saline decreases the incidence of clinical upper limb palsy (ULP;
a reduction of one grade or more on manual muscle testing; MMT),
based on the idea that ULP results from thermal damage to the nerve
roots by heat generated by friction during bone drilling. Irrigation saline for drilling was used at room temperature (RT,
25.6°C) in open-door laminoplasty in 400 patients (RT group) and
chilled to a mean temperature of 12.1°C during operations for 400
patients (low-temperature (LT) group). We assessed deltoid, biceps,
and triceps brachii muscle strength by MMT. ULP occurring within
two days post-operatively was categorised as early-onset palsy.Aims
Methods
Using the transverse processes of fresh porcine lumbar spines as an experimental model we evaluated the heat generated by a rotating burr of a high-speed drill in cutting the bone. The temperature at the drilled site reached 174°C with a diamond burr and 77°C with a steel burr. With water irrigation at a flow rate of 540 ml/hr an effective reduction in the temperature was achieved whereas irrigation with water at 180 ml/hr was much less effective. There was a significant negative correlation between the thickness of the residual bone and the temperature measured at its undersurface adjacent to the drilling site (p <
0.001). Our data suggest that tissues neighbouring the drilled bone, especially nerve roots, can be damaged by the heat generated from the tip of a high-speed drill. Nerve-root palsy, one of the most common complications of cervical spinal surgery, may be caused by thermal damage to nerve roots arising in this manner.
Inflammatory markers such as the C-reactive protein (CRP), white blood cell count and body temperature are easy to measure and are used as indicators of infection. The way in which they change in the early post-operative period after instrumented spinal surgery has not been reported in any depth. We measured these markers pre-operatively and at one, four, seven and 14 days postoperatively in 143 patients who had undergone an instrumented posterior lumbar interbody fusion. The CRP proved to be the only sensitive marker and had returned to its normal level in 48% of patients after 14 days. The CRP on day 7 was never higher than that on day 4. Age, gender, body temperature, operating time and blood loss were not related to the CRP level. A high CRP does not in itself suggest infection, but any increase after four days may presage infection.
A characteristic dysfunction of the hand has been observed in various cervical spinal disorders when there is involvement of the spinal cord. There is loss of power of adduction and extension of the ulnar two or three fingers and an inability to grip and release rapidly with these fingers. These changes have been termed "myelopathy hand" and appear to be due to pyramidal tract involvement. The characteristic nature of the signs permit the distinction between myelopathy and changes due to nerve root or peripheral nerve disorder. The clinical significance of these signs has been assessed against other tests and their value in management is discussed.
