In a double-blinded randomised controlled trial,
83 patients with primary osteoarthritis of the hip received either
a ceramic-on-metal (CoM) or metal-on-metal (MoM) total hip replacement
(THR). The implants differed only in the bearing surfaces used.
The serum levels of cobalt and chromium and functional outcome scores
were compared pre-operatively and at six and 12 months post-operatively. Data were available for 41 CoM and 36 MoM THRs (four patients
were lost to follow-up, two received incorrect implants). The baseline
characteristics of both cohorts were similar. Femoral head size
measured 36 mm in all but two patients who had 28 mm heads. The
mean serum cobalt and chromium levels increased in both groups,
with no difference noted between groups at six months (cobalt p
= 0.67, chromium p = 0.87) and 12 months (cobalt p = 0.76, chromium
p = 0.76) post-operatively. Similarly, the mean Oxford hip scores,
Western Ontario and McMaster Universities Osteoarthritis index and
University of California, Los Angeles activity scores showed comparable improvement
at 12 months. Our findings indicate that CoM and MoM couplings are associated
with an equivalent increase in serum cobalt and chromium levels,
and comparable functional outcome scores at six and 12-months follow-up.
We reviewed 39 patients with displaced three- and four-part fractures of the humerus. In 21 patients (group A) we had used an anatomical prosthesis for the humeral head and in 18 (group B) an implant designed for fractures. When followed up at a mean of 29.3 months after surgery the overall Constant score was 51.9 points; in group A it was 51.5 and in group B 52.4 points. The subjective satisfaction of the patients was assessed using a numerical rating scale and was similar in both groups. In group A complete healing of the tuberosities was found in 29% and 50% in group B. Partial integration was seen in 29% of group A and in only one patient in group B, while resorption was noted in 43% of group A and 44% of group B. The functional outcome was significantly better in patients with complete or partial healing of the tuberosities (p = 0.022). The specific trauma prosthesis did not lead to better healing of the tuberosities. The difference in clinical outcome obtained by the two designs did not reach statistical significance.
We have compared the outcome of hemiarthroplasty of the shoulder in three distinct diagnostic groups, using survival analysis as used by the United Kingdom national joint registers, patient-reported outcome measures (PROMs) as recommended by Darzi in the 2008 NHS review, and transition and satisfaction questions. A total of 72 hemiarthroplasties, 19 for primary osteoarthritis (OA) with an intact rotator cuff, 22 for OA with a torn rotator cuff, and 31 for rheumatoid arthritis (RA), were followed up for between three and eight years. All the patients survived, with no revisions or dislocations and no significant radiological evidence of loosening. The mean new Oxford shoulder score (minimum/worst 0, maximum/best 48) improved significantly for all groups (p <
0.001), in the OA group with an intact rotator cuff from 21.4 to 38.8 (effect size 2.9), in the OA group with a torn rotator cuff from 13.3 to 27.2 (effect size 2.1) and in the RA group from 13.7 to 28.0 (effect size 3.1). By this assessment, and for the survival analysis, there was no significant difference between the groups. However, when ratings using the patient satisfaction questions were analysed, eight (29.6%) of the RA group were ‘disappointed’, compared with one (9.1%) of the OA group with cuff intact and one (7.7%) of the OA group with cuff torn. All patients in the OA group with cuff torn indicated that they would undergo the operation again, compared to ten (90.9%) in the OA group with cuff intact and 20 (76.9%) in the RA group. The use of revision rates alone does not fully represent outcome after hemiarthroplasty of the shoulder. Data from PROMs provides more information about change in pain and the ability to undertake activities and perform tasks. The additional use of satisfaction ratings shows that both the rates of revision surgery and PROMs need careful interpretation in the context of patient expectations.
In 100 patients the fulcrum axis which is the line connecting the anterior tip of the coracoid and the posterolateral angle of the acromion, was used to position true anteroposterior radiographs of the shoulder. This method was then compared with the conventional radiological technique in a further 100 patients. Three orthopaedic surgeons counted the number of images without overlap between the humeral head and glenoid and calculated the amount of the glenoid surface visible in each radiograph. The analysis was repeated for intraobserver reliability. The learning curves of both techniques were studied. The amount of free visible glenoid space was significantly higher using the fulcrum-axis method (64 vs 31) and the comparable glenoid size increased significantly (8.56 vs 6.47). Thus the accuracy of the anteroposterior radiographs of the shoulder is impaired by using this technique. The intra and interobserver reliability showed a high consistency. No learning curve was observed for either technique.
This study compared the effect of a computer-assisted and a traditional surgical technique on the kinematics of the glenohumeral joint during passive abduction after hemiarthroplasty of the shoulder for the treatment of fractures. We used seven pairs of fresh-frozen cadaver shoulders to create simulated four-part fractures of the proximal humerus, which were then reconstructed with hemiarthroplasty and reattachment of the tuberosities. The specimens were randomised, so that one from each pair was repaired using the computer-assisted technique, whereas a traditional hemiarthroplasty without navigation was performed in the contralateral shoulder. Kinematic data were obtained using an electromagnetic tracking device. The traditional technique resulted in posterior and inferior translation of the humeral head. No statistical differences were observed before or after computer-assisted surgery. Although it requires further improvement, the computer-assisted approach appears to allow glenohumeral kinematics to more closely replicate those of the native joint, potentially improving the function of the shoulder and extending the longevity of the prosthesis.
In a prospective study between 2000 and 2005, 22 patients with primary osteoarthritis of the shoulder had a total shoulder arthroplasty with a standard five-pegged glenoid component, 12 with non-offset humeral head and ten with offset humeral head components. Over a period of 24 months the relative movement of the glenoid component with respect to the scapula was measured using radiostereometric analysis. Nine glenoids needed reaming for erosion. There was a significant increase in rotation about all three axes with time (p <
0.001), the largest occurring about the longitudinal axis (anteversion-retroversion), with mean values of 3.8° and 1.9° for the non-offset and offset humeral head eroded subgroups, respectively. There was also a significant difference in rotation about the anteversion-retroversion axis (p = 0.01) and the varus-valgus (p <
0.001) z-axis between the two groups. The offset humeral head group reached a plateau at early follow-up with rotation about the z-axis, whereas the mean of the non-offset humeral head group at 24 months was three times greater than that of the offset group accounting for the highly significant difference between them.
Mechanical loosening which begins with early-onset migration of the prosthesis is the major reason for failure of the Souter-Strathclyde elbow replacement. In a prospective study of 18 Souter-Strathclyde replacements we evaluated the patterns of migration using roentgen stereophotogrammetric analysis. We had previously reported the short-term results after a follow-up of two years which we have now extended to a mean follow-up of 8.2 years (1 to 11.3). Migration was assessed along the co-ordinal axes and overall micromovement was expressed as the maximum total point movement. The alignment of the prosthesis and the presence of radiolucent lines were examined on conventional standardised radiographs. All the humeral components showed increased and variable patterns of migration at the extended follow-up and four humeral components were revised. The maximum total point movement at two years in the revised prostheses was 1.8 mm (
Glenoid replacement is technically challenging. Removal of a cemented glenoid component often results in a large osseous defect which makes the immediate introduction of a revision prosthesis almost impossible. We describe a two-stage revision procedure using a reversed shoulder prosthesis. Freeze-dried allograft with platelet-derived growth factor was used to fill the glenoid defect. Radiological incorporation of the allograft was seen and its consistency allowed the placement of a screwed glenoid component. There were no signs of new mature bone formation on histological examination. The addition of platelet-derived growth factor to the allograft seems to contribute to an increase in incorporation and hardness, but does not promote the growth of new bone.
Secure fixation of displaced proximal fractures of the humerus is a challenging problem. A total of 32 patients with acutely displaced three- or four-part proximal fractures of the humerus were treated by open reduction and internal fixation using the proximal humeral internal locking system (PHILOS) plate. There were 23 women and nine men with a mean age of 59.9 years (18 to 87). Data were collected prospectively and the outcomes were assessed using the Constant score. The mean follow-up was for 11 months (3 to 24). In 31 patients (97%) the fracture united clinically and radiologically at a mean of 10 weeks (8 to 24). The mean Constant score at final review was 66.5 (30 to 92). There was no significant difference in outcome when comparing patients aged more than 60 years (18 patients) with those aged less than 60 years (14 patients) ( This plate provides an alternative method of fixation for fractures of the proximal humerus. It provides a stable fixation in young patients with good-quality bone sufficient to permit early mobilisation. Failure of the screws to maintain fixation in the elderly remains a problem.
Reversed shoulder prostheses are increasingly being used for the treatment of glenohumeral arthropathy associated with a deficient rotator cuff. These non-anatomical implants attempt to balance the joint forces by means of a semi-constrained articular surface and a medialised centre of rotation. A finite element model was used to compare a reversed prosthesis with an anatomical implant. Active abduction was simulated from 0° to 150° of elevation. With the anatomical prosthesis, the joint force almost reached the equivalence of body weight. The joint force was half this for the reversed prosthesis. The direction of force was much more vertically aligned for the reverse prosthesis, in the first 90° of abduction. With the reversed prosthesis, abduction was possible without rotator cuff muscles and required 20% less deltoid force to achieve it. This force analysis confirms the potential mechanical advantage of reversed prostheses when rotator cuff muscles are deficient.
We retrospectively identified 18 consecutive patients with synovial chrondromatosis of the shoulder who had arthroscopic treatment between 1989 and 2004. Of these, 15 were available for review at a mean follow-up of 5.3 years (2.3 to 16.5). There were seven patients with primary synovial chondromatosis, but for the remainder, the condition was a result of secondary causes. The mean Constant score showed that pain and activities of daily living were the most affected categories, being only 57% and 65% of the values of the normal side. Surgery resulted in a significant improvement in the mean Constant score in these domains from 8.9 (4 to 15) to 11.3 (2 to 15) and from 12.9 (5 to 20) to 18.7 (11 to 20), respectively (unpaired We found that arthroscopic debridement of the glenohumeral joint and open debridement and tenodesis of the long head of biceps, when indicated, are safe and effective in relieving symptoms at medium-term review.
This study evaluated the effect on movement under load of three different techniques for re-attachment of the tuberosities of the humerus using test sawbones. In the first, the tuberosities were attached both to the shaft and to each other, with one cerclage suture through the anterior hole in the prosthesis. The second technique was identical except for omission of the cerclage suture and in the third the tuberosities were attached to the prosthesis and to the shaft. An orthogonal photogrammetric system allowed all segments to be tracked in a 3D axis system. The humeri were incrementally-loaded in abduction, and the 3D linear and angular movements of all segments were calculated. Displacement between the tuberosities and the shaft was measured. The first and second techniques were the most stable constructs, with the third allowing greater separation of fragments and angular movement. Separation at the midpoint of the tuberosities was significantly greater using the latter technique (p <
0.05). The cerclage suture added no further stability to the fixation.
This study reviews the predisposing features, the clinical, and laboratory findings at the time of diagnosis and the results of single-stage revision of prosthetic replacement of the elbow for infection. Deep infection occurred in six of 305 (1.9%) primary total elbow replacements. The mean follow-up after revision was 6.8 years (6 months to 16 years) and the mean age at the time of revision was 62.7 years (56 to 74). All six cases with infection had rheumatoid arthritis and had received steroid therapy. The infective organism was
Replacement of the shoulder in juvenile idiopathic arthritis is not often performed and there have been no published series to date. We present nine glenohumeral hemiarthroplasties in eight patients with systemic or polyarticular juvenile idiopathic arthritis. The mean follow-up was six years (59 to 89 months). The mean age at the time of surgery was 32 years. Surgery took place at a mean of 27 years after diagnosis. The results indicated excellent relief from pain. There was restoration of useful function which deteriorated with time, in part because of progression of the systemic disease in this severely affected group. No patient has required revision to date and there has been no radiological evidence of loosening or osteolysis around the implants. We discuss the pathoanatomical challenges unique to this group. There was very little space for a prosthetic joint and, in some cases, bony deformity and the small size necessitated the use of custom-made implants.