Patients with skeletal dysplasia are prone to
developing advanced osteoarthritis of the knee requiring total knee replacement
(TKR) at a younger age than the general population. TKR in this
unique group of patients is a technically demanding procedure owing
to the deformity, flexion contracture, generalised hypotonia and ligamentous
laxity. We retrospectively reviewed the outcome of 11 TKRs performed
in eight patients with skeletal dysplasia at our institution using
the Stanmore Modular Individualised Lower Extremity System (SMILES)
custom-made rotating-hinge TKR. There were three men and five women
with mean age of 57 years (41 to 79). Patients were followed clinically
and radiologically for a mean of seven years (3 to 11.5). The mean
Knee Society clinical and function scores improved from 24 (14 to
36) and 20 (5 to 40) pre-operatively, respectively, to 68 (28 to
80) and 50 (22 to 74), respectively, at final follow-up. Four complications
were recorded, including a patellar fracture following a fall, a
tibial peri-prosthetic fracture, persistent anterior knee pain,
and aseptic loosening of a femoral component requiring revision.
Our results demonstrate that custom primary rotating-hinge TKR in
patients with skeletal dysplasia is effective at relieving pain,
with a satisfactory range of movement and improved function. It compensates
for bony deformity and ligament deficiency and reduces the likelihood
of corrective osteotomy. Patellofemoral joint complications are
frequent and functional outcome is worse than with primary TKR in
the general population.
We compared the performance of uncemented trabecular metal tibial components in total knee replacement with that of cemented tibial components in patients younger than 60 years over two years using radiostereophotogrammetric analysis (RSA). A total of 22 consecutive patients (mean age 53 years, 33 to 59, 26 knees) received an uncemented NexGen trabecular metal cruciate-retaining monobloc tibial component and 19 (mean 53 years, 44 to 59, 21 knees) a cemented NexGen Option cruciate-retaining modular tibial component. All the trabecular metal components migrated during the initial three months and then stabilised. The exception was external rotation, which did not stabilise until 12 months. Unlike conventional metal-backed implants which displayed a tilting migration comprising subsidence and lift-off from the tibial tray, most of the trabecular metal components showed subsidence only, probably due to the elasticity of the implant. This pattern of subsidence is regarded as being beneficial for uncemented fixation.
We retrospectively studied the major complications occurring after one- and two-stage bilateral unicompartmental knee replacements (UKR). Between 1999 and 2008, 911 patients underwent 1150 UKRs through a minimally invasive approach in our unit. Of these, 159 patients (318 UKRs) had one-stage and 80 patients (160 UKRs) had two-stage bilateral UKRs. The bilateral UKR groups were comparable in age and American Society of Anaesthesiology grade, but more women were in the two-stage group (p = 0.019). Mechanical thromboprophylaxis was used in all cases. Major complications were recorded as death, pulmonary embolus, proximal deep-vein thrombosis and adverse cardiac events within 30 days of surgery. No statistical differences between the groups were found regarding the operating surgeon, the tourniquet time or minor complications except for distal deep-vein thrombosis. The anaesthetic times were longer for the two-stage group (p = 0.0001). Major complications were seen in 13 patients (8.2%) with one-stage operations but none were encountered in the two-stage group (p = 0.005). Distal deep-vein thrombosis was more frequent in the two-stage group (p = 0.036). Because of the significantly higher risk of major complications associated with one-stage bilateral UKR we advocate caution before undertaking such a procedure.
The Oxford Unicompartmental Knee replacement (UKR) was introduced as a design to reduce polyethylene wear. There has been one previous retrieval study involving this implant, which reported very low rates of wear in some specimens but abnormal patterns of wear in others. There has been no further investigation of these abnormal patterns. The bearings were retrieved from 47 patients who had received a medial Oxford UKR for anteromedial osteoarthritis of the knee. None had been studied previously. The mean time to revision was 8.4 years ( These results show that very low rates of polyethylene wear are possible if the device functions normally. However, if the bearing displays suboptimal function (extra-articular, intra-articular impingement or incongruous articulation) the rates of wear increase significantly.
Treatment strategies for osteoarthritis most commonly involve the removal or replacement of damaged joint tissue. Relatively few treatments attempt to arrest, slow down or reverse the disease process. Such options include peri-articular osteotomy around the hip or knee, and treatment of femoro-acetabular impingement, where early intervention may potentially alter the natural history of the disease. A relatively small proportion of patients with osteoarthritis have a clear predisposing factor that is both suitable for modification and who present early enough for intervention to be deemed worthwhile. This paper reviews recent advances in our understanding of the pathology, imaging and progression of early osteoarthritis.
There has been a substantial increase in the
number of hip and knee prostheses implanted in recent years, with
a consequent increase in the number of revisions required. Total
femur replacement (TFR) following destruction of the entire femur,
usually after several previous revision operations, is a rare procedure
but is the only way of avoiding amputation. Intramedullary femur
replacement (IFR) with preservation of the femoral diaphysis is
a modification of TFR. Between 1999 and 2010, 27 patients with non-oncological
conditions underwent surgery in our department with either IFR (n
= 15) or TFR (n = 12) and were included in this study retrospectively.
The aim of the study was to assess the indications, complications
and outcomes of IFR and TFR in revision cases. The mean follow-up
period was 31.3 months (6 to 90). Complications developed in 37%
of cases, 33% in the IFR group and 4% in the TFR group. Despite
a trend towards a slightly better functional outcome compared with
TFR, the indication for intramedullary femur replacement should
be established on a very strict basis in view of the procedure’s
much higher complication rate.
We report the long-term survival of a prospective randomised consecutive series of 501 primary knee replacements using the press-fit condylar posterior cruciate ligament-retaining prosthesis. Patients received either cemented (219 patients, 277 implants) or cementless (177 patients, 224 implants) fixation. Altogether, 44 of 501 knees (8.8%) underwent revision surgery (24 cemented This single-surgeon series, with no loss to follow-up, provides reliable data of the revision rates of one of the most commonly-used total knee replacements. The survival of the press-fit condylar total knee replacement remained good at 15 years, irrespective of the method of fixation.
This multicentre study analysed 12 alumina ceramic-on-ceramic
components retrieved from squeaking total hip replacements after
a mean of 23 months
In 2004 we described the ten-year prospective results of 38 total hip replacements using the Furlong hydroxyapatite-ceramic-coated femoral component in 35 patients <
50 years old. We have now reviewed the surviving 35 arthroplasties in 33 patients at a mean of 16 years (10.3 to 19.9). The mean age of the surviving patients at the time of operation was 41.3 years (26.0 to 49.0). Of these, eight have undergone revision of their acetabular component for aseptic loosening. None of the femoral components has had revision for aseptic loosening giving a survival rate of 100% at 16 years (95% confidence interval 89% to 100%). The Furlong hydroxyapatite-ceramic-coated femoral component gives excellent long-term survival in young and active patients.
Given the growing prevalence of obesity around
the world and its association with osteoarthritis of the knee, orthopaedic
surgeons need to be familiar with the management of the obese patient
with degenerative knee pain. The precise mechanism by which obesity
leads to osteoarthritis remains unknown, but is likely to be due
to a combination of mechanical, humoral and genetic factors. Weight loss has clear medical benefits for the obese patient
and seems to be a logical way of relieving joint pain associated
with degenerative arthritis. There are a variety of ways in which
this may be done including diet and exercise, and treatment with
drugs and bariatric surgery. Whether substantial weight loss can
delay or even reverse the symptoms associated with osteoarthritis
remains to be seen. Surgery for osteoarthritis in the obese patient can be technically
more challenging and carries a risk of additional complications.
Substantial weight loss before undertaking total knee replacement
is advisable. More prospective studies that evaluate the effect
of significant weight loss on the evolution of symptomatic osteoarthritis
of the knee are needed so that orthopaedic surgeons can treat this
patient group appropriately.
We have carried out a radiostereometric study of 50 patients (54 knees) with osteoarthritis of the knee who were randomly allocated to receive a cemented or a hydroxyapatite-coated femoral component for total knee replacement. The patients were also stratified to receive one of three types of articulating surface (standard, rotating platform, Freeman-Samuelson (FS)1000) all based on the Freeman-Samuelson design. The tibial components were cemented in all cases. Radiostereometry was performed post-operatively and at 3, 12 and 24 months. The analysis was restricted to rotation of the femoral component over time. After two years, rotation of the femoral components in the transverse, longitudinal and sagittal planes did not differ between the cemented and the hydroxyapatite-coated implants (p = 0.2 to 0.9). In total knee replacements with a rotating platform, the femoral component tended to tilt more posteriorly than in the other two designs, regardless of the choice of fixation (cemented or hydroxyapatite-coated, p = 0.04). The standard version of the femoral component, whether cemented or hydroxyapatite-coated, rotated more into valgus than was observed with the rotating-platform and FS1000 designs (p = 0.005). The increased constraint provided by the FS1000 component did not appear to have any adverse effect on fixation of the femoral component.
We randomised 62 knees to receive either cemented or cementless versions of the Oxford unicompartmental knee replacement. The implants used in both arms of the study were similar, except that the cementless components were coated with porous titanium and hydroxyapatite. The tibial interfaces were studied with fluoroscopically-aligned radiographs. At one year there was no difference in clinical outcome between the two groups. Narrow radiolucent lines were seen at the bone-implant interfaces in 75% of cemented tibial components. These were partial in 43%, and complete in 32%. In the cementless implants, partial radiolucencies were seen in 7% and complete radiolucencies in none. These differences are statistically significant (p <
0.0001) and imply satisfactory bone ingrowth into the cementless implants.
The routine administration of prophylactic antibiotics for dental interventions to prevent haematogenous spread of infections to prosthetic joints is a contentious issue. In this editorial we discuss the potentially harmful effects of this practice and propose an alternative solution.
We evaluated the incidence of heterotopic ossification
following total ankle replacement to determine whether the degree
of ossification was associated with the clinical outcome. We evaluated
90 ankles in 81 consecutive patients who underwent total ankle replacement,
and heterotopic ossification was assessed according to proportional involvement
of the ankle joint. Correlation analysis was used to investigate
the association between heterotopic ossification and outcome. No significant association was found between the formation of
heterotopic ossification and the clinical outcome. The degree of
heterotopic ossification in the posterior ankle joint was not significantly
correlated with posterior ankle pain (p = 0.929), the American Orthopaedic
Foot and Ankle Society score (p = 0.454) or range of movement (p
= 0.283). This study indicates that caution should be observed in attributing
symptoms and functional limitation to the presence of heterotopic
ossification in the posterior ankle joint when considering excision
of heterotopic bone after total ankle replacement.
Since the Oxford knee was first used unicompartmentally
in 1982, a small number of bearings have fractured. Of 14 retrieved
bearings, we examined ten samples with known durations
The effect of weight-bearing on the height of the patellar using four radiological indices was studied in 25 healthy men using lateral radiographs of the knee in 30° of flexion non-weight-bearing and weight-bearing. The position of the patella was quantified using the Insall-Salvati, the modified Insall-Salvati, the Blackburne-Peel and the Caton indices. The contraction of the quadriceps on weight-bearing resulted in statistically significant proximal displacement of the patella with all four indices studied. The mean Insall-Salvati index was 0.919 ( The effect of quadriceps contraction should be considered in clinical studies where the patellar position indices are reported.
We compared thromboembolic events, major haemorrhage
and death after total hip replacement in patients receiving either
aspirin or low-molecular-weight heparin (LMWH). We analysed data from
the National Joint Registry for England and Wales linked to an administrative
database of hospital admissions in the English National Health Service.
A total of 108 584 patients operated on between April 2003 and September 2008
were included and followed up for 90 days. Multivariable risk modelling
and propensity score matching were used to estimate odds ratios
(OR) adjusted for baseline risk factors. An OR <
1 indicates
that rates are lower with LMWH than with aspirin. In all, 21.1%
of patients were prescribed aspirin and 78.9% LMWH. Without adjustment, we
found no statistically significant differences. The rate of pulmonary
embolism was 0.68% in both groups and 90-day mortality was 0.65%
with aspirin and 0.61% with LMWH (OR 0.93; 95% CI 0.77 to 1.11).
With risk adjustment, the difference in mortality increased (OR
0.84; 95% CI 0.69 to 1.01). With propensity score matching the mortality difference
increased even further to 0.65% with aspirin and 0.51% with LMWH
(OR 0.77; 95% CI 0.61 to 0.98). These results should be considered
when the conflicting recommendations of existing guidelines for
thromboprophylaxis after hip replacement are being addressed.
We evaluated the safety and efficacy of total
knee replacement in patients receiving continuous warfarin therapy. We identified 24 consecutive patients receiving long-term warfarin
therapy who underwent total knee replacement between 2006 and 2008
and compared them with a group of age- and gender-matched patients
not on long-term anticoagulation. Primary observations were changes
in haemoglobin, transfusion rates and complications. Secondary observations
were fluctuations in the international normalised ratio (INR) and
post-operative range of movement. There was no significant difference between the two groups in
pre- or post-operative haemoglobin, incidence of transfusion or
incidence of post-operative complications. There were no surgical
delays due to a high INR level. The mean change in INR during the
peri-operative phase was minimal (mean 0.4; Current American College of Chest Physicians guidelines recommend
bridging therapy for high-risk patients receiving oral anticoagulation
and undergoing major orthopaedic procedures. We have shown that
a safe alternative is to continue the steady-state warfarin peri-operatively
in patients on long-term anticoagulation requiring total knee replacement.
Post-discharge surveillance of surgical site infection is necessary if accurate rates of infection following surgery are to be available. We undertook a prospective study of 376 knee and hip replacements in 366 patients in order to estimate the rate of orthopaedic surgical site infection in the community. The inpatient infection was 3.1% and the post-discharge infection rate was 2.1%. We concluded that the use of telephone interviews of patients to identify the group at highest risk of having a surgical site infection (those who think they have an infection) with rapid follow-up by a professional trained to diagnose infection according to agreed criteria is an effective method of identifying infection after discharge from hospital.