Failure ofconservative treatment is the usual indication for the reconstruction of a knee with deficiency of the anterior cruciate ligament (ACL) and this depends on subjective judgement. The ability of muscles to protect the subluxing joint by reflex contraction could provide an objective measurement. We have studied 30 patients with unilateral ACL deficiency by measuring the latency of reflex hamstring contraction. We found that the mean latency in the injured leg was nearly twice that in the unaffected limb (99 ms and 53 ms respectively). There was a significant correlation between the differential latency and the frequency of 'giving way' indicating that functional instabifity may be due, in part, to loss of proprioception. Measures of proprioception, including reflex hamstring latency, may be useful in providing an objective assessment of the efficacy of conservative treatment and the need for surgery.

Decreased dynamic stability of the knee joint associated with functional disability is a feature of anterior cruciate ligament deficiency (ACLD). The purposes of this study were to examine the between-limbs difference in reflex contraction latency of the hamstring muscles in patients with unilateral ACLD and to investigate its relationship with instability and function. Fifty patients with arthroscopically diagnosed unilateral ACLD were measured bilaterally for reflex hamstring contraction latency (RHCL), and 20 normal volunteers were similarly tested. The subjects were measured in a position of single-limb full weight-bearing with the knee flexed 30 degrees. An anteriorly directed shear force was applied to the tibia, and surface electromyographs (EMGs) recorded the activity of the hamstrings in response to the applied force. The latency of contraction was defined as the time from initial tibial movement, identified by accelerometry, to the onset of increased hamstring EMG activity. Both legs were tested and a between-limbs difference was computed. A significant difference in RHCL was found between the limb with ACLD and the control limb. The mean RHCL of the limb with ACLD was nearly double that of the unaffected limb, for a significant mean between-limbs difference (p < 0.05). The mean between-limbs difference for the control subjects was not statistically significant. The conclusion is that patients with ACLD have an increased RHCL of the injured leg. As the RHCL is dependent on proprioceptive activity around the joint, it can be used as a measure of proprioceptive ability. The loss of the neurophysiological protective reflex involving the anterior cruciate ligament and hamstrings in patients with ACLD is likely to be a contributory factor in the decreased joint stability experienced by these patients.

The results of a study of the use of autograft versus allograft bone in the surgery of idiopathic adolescent scoliosis are presented.

Generalized OA (GOA) is a well-characterized subset of primary OA which is strongly associated with the occurrence of Heberden's nodes. Using gene-specific highly polymorphic markers and affected sib pair (ASP) analyses, we have investigated genetic linkage between GOA and three cartilage matrix genes: COL2A1 which encodes type II collagen; CRTL1 which encodes the cartilage link protein and CRTM which encodes the cartilage matrix protein. The analyses showed no linkage between GOA and the three genes in the 38 sib pairs examined. Since we examined a relatively modest number of sib pairs, our results can only exclude COL2A1, CRTL1 and CRTM as major susceptibility loci for GOA.

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