We assessed proprioception using threshold levels for the perception of knee movement at slow angular velocities (0.1°/s to 0.85°/s) in 20 patients with unilateral tears of the anterior cruciate ligament (ACL) and 15 age-related control subjects. Failure to detect movement was also analysed. The threshold levels of detection did not differ between the damaged and undamaged knees in the patients or between the patients and the control group. Failure to appreciate movement, however, was significantly greater in knees with ACL loss compared with the undamaged knees of patients and the control group. Our findings show a proprioceptive deficit in the absence of the ACL. Measurements of threshold levels of detection of passive movement alone are not suitable for the evaluation of proprioceptive loss in ACL deficiency; assessment of failure to appreciate movement is essential

Aims

To fully verify the reliability and reproducibility of an experimental method in generating standardized micromotion for the rat femur fracture model.

Aims

Wear of the polyethylene (PE) tibial insert of total knee arthroplasty (TKA) increases the risk of revision surgery with a significant cost burden on the healthcare system. This study quantifies wear performance of tibial inserts in a large and diverse series of retrieved TKAs to evaluate the effect of factors related to the patient, knee design, and bearing material on tibial insert wear performance.

1 . The results of compression arthrodesis of the hip have been studied in fifty-six patients. There was one post-operative death from pulmonary embolism on the tenth day. 2. Bony union for the whole series (fifty-five patients) was achieved in 76·4 per cent. Sound fibrous ankylosis, indistinguishable from bony union clinically and functionally, was achieved in 10·9 per cent. Residual movement occurred in 12·7 per cent. 3. Thirty-five patients were treated by the standard technique of eight weeks in plaster, followed by full weight bearing, irrespective of whether any movement was detected on clinical testing. 82·8 per cent achieved sound bony union; 5·7 per cent achieved sound fibrous ankylosis, and residual movement occurred in 11·4 per cent. 4. Ten patients were treated without plaster protection; six achieved bony union; three had sound fibrous ankylosis and one had residual movement. Healing was delayed in this group and there was more residual deformity. 5. 67·5 per cent of all patients recovered full knee range. Only one patient with reduced range had knee flexion of less than 90 degrees. Twenty-four of the thirty-five patients treated by the standard technique of eight weeks in plaster were examined. Fifteen had full knee movement; in only four was knee flexion less than 120 degrees and in no case was it less than 90 degrees. 6. Return to full activity was rapid. Sixty per cent of patients returned to work within six months and 80 per cent within nine months of surgery. Five of the six patients examined with residual movement in the hip joint were back at work within six months of surgery. 7. This study lends support to the view that arthrodesis of the hip, in the presence of normal function in the opposite hip, is compatible with vigorous and full activity

Aims. The aims of this study were to determine the proportion of patients with outlier varus or valgus alignment in kinematically aligned total knee arthroplasty (TKA), whether those with outlier varus or valgus alignment have higher forces in the medial or lateral compartments of the knee than those with in-range alignment and whether measurements of the alignment of the limb, knee and components predict compartment forces. Patients and Methods. The intra-operative forces in the medial and lateral compartments were measured with an instrumented tibial insert in 67 patients who underwent a kinematically aligned TKA during passive movement. The mean of the forces at full extension, 45° and 90° of flexion determined the force in the medial and lateral compartments. Measurements of the alignment of the limb and the components included the hip-knee-ankle (HKA) angle, proximal medial tibial angle (PMTA), and distal lateral femoral angle (DLFA). Measurements of the alignment of the knee and the components included the tibiofemoral angle (TFA), tibial component angle (TCA) and femoral component angle (FCA). Alignment was measured on post-operative, non-weight-bearing anteroposterior (AP) scanograms and categorised as varus or valgus outlier or in-range in relation to mechanically aligned criteria. Results. The proportion of patients with outlier varus or valgus alignment was 16%/24% for the HKA angle, 55%/0% for the PMTA, 0%/57% for the DLFA, 25%/12% for the TFA, 100%/0% for the TCA, and 0%/64% for the FCA. In general, the forces in the medial and lateral compartments of those with outlier alignment were not different from those with in-range alignment except for the TFA, in which patients with outlier varus alignment had a mean paradoxical force which was 6 lb higher in the lateral compartment than those with in-range alignment. None of the measurements of alignment of the limb, knee and components predicted the force in the medial or lateral compartment. Conclusion. Although kinematically aligned TKA has a high proportion of varus or valgus outliers using mechanically aligned criteria, the intra-operative forces in the medial and lateral compartments of patients with outlier alignment were comparable with those with in-range alignment, with no evidence of overload of the medial or lateral compartment of the knee. Cite this article: Bone Joint J 2017;99-B:1319–28

The success of total knee replacement (TKR) depends on optimal soft-tissue balancing, among many other factors. The objective of this study is to correlate post-operative anteroposterior (AP) translation of a posterior cruciate ligament-retaining TKR with clinical outcome at two years. In total 100 patients were divided into three groups based on their AP translation as measured by the KT-1000 arthrometer. Group 1 patients had AP translation < 5 mm, Group 2 had AP translation from 5 mm to 10 mm, and Group 3 had AP translation >  10 mm. Outcome assessment included range of movement of the knee, the presence of flexion contractures, hyperextension, knee mechanical axes and functional outcome using the Knee Society score, Oxford knee score and the Short-Form 36 questionnaire. At two years, patients in Group 2 reported significantly better Oxford knee scores than the other groups (p = 0.045). A positive correlation between range of movement and AP translation was noted, with patients in group 3 having the greatest range of movement (mean flexion: 117.9° (106° to 130°)) (p < 0.001). However, significantly more patients in Group 3 developed hyperextension > 10° (p = 0.01). In this study, the best outcome for cruciate-ligament retaining TKR was achieved in patients with an AP translation of 5 mm to 10 mm

Aims. A failed total ankle arthroplasty (TAA) is often associated with much bone loss. As an alternative to arthrodesis, the surgeon may consider a custom-made talar component to compensate for the bone loss. Our aim in this study was to assess the functional and radiological outcome after the use of such a component at mid- to long-term follow-up. Patients and Methods. A total of 12 patients (five women and seven men, mean age 53 years; 36 to77) with a failed TAA and a large talar defect underwent a revision procedure using a custom-made talar component. The design of the custom-made components was based on CT scans and standard radiographs, when compared with the contralateral ankle. After the anterior talocalcaneal joint was fused, the talar component was introduced and fixed to the body of the calcaneum. Results. At a mean follow-up of 6.9 years (1 to 13), 11 ankles were stable with no radiological evidence of loosening. Only one was lost to follow-up. The mean arc of movement was 21. °. (10. °. to 35. °. ). A total of nine patients (75%) were satisfied or very satisfied with the outcome, two (17%) were satisfied but with reservations and one (8%) was not satisfied. All but one patient had an improvement in the American Orthopaedic Foot and Ankle Society hindfoot score (p = 0.01). Just one patient developed deep infection, leading to arthrodesis. Conclusion. A custom-made talar component yielded satisfactory results with regard to function, stability and satisfaction. This should encourage the use of such components as an alternative to arthrodesis of the ankle in patients with a failed TAA. Cite this article: Bone Joint J 2017;99-B:231–6

Cervical spinal disc replacement is used in the management of degenerative cervical disc disease in an attempt to preserve cervical spinal movement and to prevent adjacent disc overload and subsequent degeneration. A large number of patients have undergone cervical spinal disc replacement, but the effectiveness of these implants is still uncertain. In most instances, degenerative change at adjacent levels represents the physiological progression of the natural history of the arthritic disc, and is unrelated to the surgeon. Complications of cervical disc replacement include loss of movement from periprosthetic ankylosis and ossification, neurological deficit, loosening and failure of the device, and worsening of any cervical kyphosis. Strict selection criteria and adherence to scientific evidence are necessary. Only prospective, randomised clinical trials with long-term follow-up will establish any real advantage of cervical spinal disc replacement over fusion

We studied the effect of 'dynamisation' on tibial fractures in six patients treated by the Dynamic Axial Fixator. In the early stages, peak cyclic movement at two to four weeks averaged 0.75 mm (0.19 to 1.02) on the medial side of the bone and 0.86 mm (0.21 to 1.25) on the lateral side. The amount of movement correlated with the applied load and the fracture stiffness. After unlocking the fixator column at six weeks, progressive closure of the gap averaged 1.3 mm (0.1 to 3.5). Cyclic movement is produced by early weight-bearing with the fixator column locked. Progressive closure occurs after unlocking the column, and is often associated with a reduction in cyclic movements. The effects of dynamisation on movement at the fracture site should be defined separately, in terms of cyclic movement and of progressive closure

Aims

Acetabular edge-loading was a cause of increased wear rates in metal-on-metal hip arthroplasties, ultimately contributing to their failure. Although such wear patterns have been regularly reported in retrieval analyses, this study aimed to determine their in vivo location and investigate their relationship with acetabular component positioning.

The biomechanical function of the anteromedial (AM) and posterolateral (PL) bundles of the anterior cruciate ligament (ACL) remains controversial. Some studies report that the AM bundle stabilises the knee joint in anteroposterior (AP) translation and rotational movement (both internal and external) to the same extent as the PL bundle. Others conclude that the PL bundle is more important than the AM in controlling rotational movement. The objective of this randomised cohort study involving 60 patients (39 men and 21 women) with a mean age of 32.9 years (18 to 53) was to evaluate the function of the AM and the PL bundles of the ACL in both AP and rotational movements of the knee joint after single-bundle and double-bundle ACL reconstruction using a computer navigation system. In the double-bundle group the patients were also randomised to have the AM or the PL bundle tensioned first, with knee laxity measured after each stage of reconstruction. All patients had isolated complete ACL tears, and the presence of a meniscal injury was the only supplementary pathology permitted for inclusion in the trial. The KT-1000 arthrometer was used to apply a constant load to evaluate the AP translation and the rolimeter was used to apply a constant rotational force. For the single-bundle group deviation was measured before and after ACL reconstruction. In the double-bundle group deviation was measured for the ACL-deficient, AM- or PL-reconstructed first conditions and for the total reconstruction. We found that the AM bundle in the double-bundle group controlled rotation as much as the single-bundle technique, and to a greater extent than the PL bundle in the double-bundle technique. The double-bundle technique increases AP translation and rotational stability in internal rotation more than the single-bundle technique

Aims

The aim of this study was to establish a reliable method for producing 3D reconstruction of sonographic callus.

Advanced osteoarthritis of the wrist or the distal articulation of the lunate with the capitate has traditionally been treated surgically by arthrodesis. In order to maintain movement, we performed proximal row carpectomy with capsular interposition arthroplasty as an alternative to arthrodesis in eight patients with advanced arthritis and retrospectively reviewed their clinical and radiographic outcomes after a mean follow-up of 41 months (13 to 53). The visual analogue scale (VAS) for pain at its worst and at rest, and the patient-rated wrist evaluation score improved significantly after surgery, whereas ranges of movement and grip strength were maintained at the pre-operative levels. Progression of arthritis in the radiocapitate joint was observed in three patients, but their outcomes were not significantly different from those without progression of arthritis. Proximal row carpectomy with capsular interposition arthroplasty is a reasonable option for the treatment of patients with advanced arthritis of the wrist

Aims

Medial pivot (MP) total knee arthroplasties (TKAs) were designed to mimic native knee kinematics with their deep medial congruent fitting of the tibia to the femur almost like a ball-on-socket, and a flat lateral part. GMK Sphere is a novel MP implant. Our primary aim was to study the migration pattern of the tibial tray of this TKA.

Aims

Cam and pincer morphologies are potential precursors to hip osteoarthritis and important contributors to non-arthritic hip pain. However, only some hips with these pathomorphologies develop symptoms and joint degeneration, and it is not clear why. Anterior impingement between the femoral head-neck contour and acetabular rim in positions of hip flexion combined with rotation is a proposed pathomechanism in these hips, but this has not been studied in active postures. Our aim was to assess the anterior impingement pathomechanism in both active and passive postures with high hip flexion that are thought to provoke impingement.

The human acetabulofemoral joint is commonly modelled as a pure ball-and-socket joint, but there has been no quantitative assessment of this assumption in the literature. Our aim was to test the limits and validity of this hypothesis. We performed experiments on four adult cadavers. Cortical pins, each equipped with a marker cluster, were implanted in the pelvis and the femur. Movements were recorded using stereophotogrammetry while an operator rotated the cadaver’s acetabulofemoral joint, exploiting the widest possible range of movement. The functional consistency of the acetabulofemoral joint as a pure spherical joint was assessed by comparing the magnitude of the translations of the hip joint centre as obtained on cadavers, with the centre of rotation of two metal segments linked through a perfectly spherical hinge. The results showed that the radii of the spheres containing 95% of the positions of the estimated centres of rotation were separated by less than 1 mm for both the acetabulofemoral joint and the mechanical spherical hinge. Therefore, the acetabulofemoral joint can be modelled as a spherical joint within the considered range of movement (flexion/extension 20° to 70°; abduction/adduction 0° to 45°; internal/external rotation 0° to 30°)

A total of 187 patients with primary osteoarthritis (OA) of the knee undergoing total knee replacement (TKR) were randomly divided into two groups, one of which underwent synovectomy. The patients and assessors were blinded to the randomisation both before and after surgery. The duration of surgery, hospitalisation period, concealed bleeding, drainage volume, blood transfusion rate and range of movement of the knee at three days after the operation were analysed. Patients were followed up at four weeks and 12 months after their operation, and a visual analogue score (VAS) for pain, Knee Society score (KSS) and a patellar ballottement test were compared between the groups. The mean amount of concealed bleeding was higher in the synovectomy group compared with the control group (1.24 l (0.08 to 3.28) vs 1.03 l (0.16 to 2.94); p = 0.042), as was the mean drainage volume (0.90 l (0.35 to 1.81) vs 0.81 (0.25 to 1.65); p = 0.030). The mean operating time was also higher in the synovectomy group compared with the controls (1.50 hours (1.34 to 1.75) vs 1.41 hours (1.21 to 1.79); p = 0.006). There were no significant differences in blood transfusion rate (p = 0.882), hospital stay (p = 0.805) or range of movement of the knee (p = 0.413) between the two groups. At four weeks and 12 months post-operatively there were no statistically significant differences in any of the measured parameters. We concluded that synovectomy confers no clinical advantages in TKR for primary OA while subjecting patients to higher levels of bleeding and longer operating times. Cite this article: Bone Joint J 2013;95-B:1197–200

We assessed the long-term (20 years) outcome of closed reduction and immobilisation in 19 patients with an isolated fracture of the posterior malleolus of the ankle treated at a single hospital between 1985 and 1990. The assessments used were an Olerud functional questionnaire score, physical examination using a loaded dorsal and plantar range of movement measurement, radiological analysis of medial joint space widening, the Cedell score for anatomical alignment of all three malleoli, and the radiological presence of osteoarthritic change. . There were excellent or good results in 14 patients (74%) according to the Olerud score, in 18 patients (95%) according to loaded dorsal and plantar range of movement assessment, in 16 patients (84%) as judged by the Cedell score, and for osteoarthritis 18 patients (95%) had an excellent or good score. There were no poor outcomes. There was no correlation between the size of the fracture gap and the proportion of the tibiotalar contact area when compared with the clinical results (gap size: rho values -0.16 to 0.04, p ≥ 0.51; tibiotalar contact area: rho values -0.20 to -0.03, p ≥ 0.4). Conservative treatment of ‘isolated’ posterior malleolar fractures resulted in good clinical and radiological outcome in this series at long-term follow-up.

Assessment of bony union after anterior fusion of the lumbar spine has previously relied on the skilled interpretation of plain radiograph. A biplanar radiographic technique was used to measure small movements between vertebrae and to give a quantitative measure of bony union in 11 patients who had undergone interbody fusion with autogenous bone chips at one level in the lumbar spine. The investigation gave three types of results: bony union, where the fused level showed marked restriction of movement relative to the rest of the lumbar spine; paradoxical movement, where the fused joint showed marked reverse movement (when the patient flexed, the fused level of the lumbar spine extended) which was thought to be due to an anterior bony bar which caused an altered pattern of movement; and non-union, where the level of fusion showed no restriction of movement. The intervertebral joint above the level of fusion was shown to move more than the other joints in the lumbar spine. The study showed that bony union is possible with the use of autogenous cancellous bone chips, and that biplanar radiographic technique can determine the extent of union