We analysed whether a high body mass index (BMI)
had a deleterious effect on outcome following autologous chondrocyte
implantation (ACI) or matrix-carried autologous chondrocyte implantation
(MACI) for the treatment of full-thickness chondral defects of the
knee from a subset of patients enrolled in the ACI vs MACI trial
at The Royal National Orthopaedic Hospital. The mean Modified Cincinnati scores (MCS) were significantly
higher (p <
0.001) post-operatively in patients who had an ideal
body weight (n = 53; 20 to 24.9 kg/m2) than in overweight
(n = 63; 25 to 30 kg/m2) and obese patients (n = 22;
>
30 kg/m2). At a follow-up of two years, obese patients
demonstrated no sustained improvement in the MCS. Patients with
an ideal weight experienced significant improvements as early as
six months after surgery (p = 0.007). In total, 82% of patients
(31 of 38) in the ideal group had a good or excellent result, compared
with 49% (22 of 45) of the overweight and 5.5% (one of 18) in the
obese group (p <
0.001). There was a significant negative relationship between
BMI and the MCS 24 months after surgery (r = -0.4, p = 0.001). This study demonstrates that obese patients have worse knee function
before surgery and experience no sustained benefit from ACI or MACI
at two years after surgery. There was a correlation between increasing
BMI and a lower MCS according to a linear regression analysis. On
the basis of our findings patient selection can be more appropriately
targeted.
The Oxford mobile-bearing unicompartmental knee
replacement (UKR) is an effective and safe treatment for osteoarthritis
of the medial compartment. The results in the lateral compartment
have been disappointing due to a high early rate of dislocation
of the bearing. A series using a newly designed domed tibial component
is reported. The first 50 consecutive domed lateral Oxford UKRs in 50 patients
with a mean follow-up of three years (2.0 to 4.3) were included.
Clinical scores were obtained prospectively and Kaplan-Meier survival
analysis was performed for different endpoints. Radiological variables
related to the position and alignment of the components were measured. One patient died and none was lost to follow-up. The cumulative
incidence of dislocation was 6.2% (95% confidence interval (CI)
2.0 to 17.9) at three years. Survival using revision for any reason
and aseptic revision was 94% (95% CI 82 to 98) and 96% (95% CI 85
to 99) at three years, respectively. Outcome scores, visual analogue
scale for pain and maximum knee flexion showed a significant improvement
(p <
0.001). The mean Oxford knee score was 43 ( Clinical results are excellent and short-term survival has improved
when compared with earlier series. The risk of dislocation remains
higher using a mobile-bearing UKR in the lateral compartment when
compared with the medial compartment. Patients should be informed
about this complication. To avoid dislocations, care must be taken
not to elevate the lateral joint line.
The aim of this study was to define return to
theatre (RTT) rates for elective hip and knee replacement (HR and
KR), to describe the predictors and to show the variations in risk-adjusted
rates by surgical team and hospital using national English hospital
administrative data. We examined information on 260 206 HRs and 315 249 KRs undertaken
between April 2007 and March 2012. The 90-day RTT rates were 2.1%
for HR and 1.8% for KR. Male gender, obesity, diabetes and several
other comorbidities were associated with higher odds for both index
procedures. For HR, hip resurfacing had half the odds of cement fixation
(OR = 0.58, 95% confidence intervals (CI) 0.47 to 0.71). For KR,
unicondylar KR had half the odds of total replacement (OR = 0.49,
95% CI 0.42 to 0.56), and younger ages had higher odds (OR = 2.23,
95% CI 1.65 to 3.01) for ages <
40 years compared with ages 60
to 69 years). There were more funnel plot outliers at three standard deviations
than would be expected if variation occurred on a random basis. Hierarchical modelling showed that three-quarters of the variation
between surgeons for HR and over half the variation between surgeons
for KR are not explained by the hospital they operated at or by
available patient factors. We conclude that 90-day RTT rate may
be a useful quality indicator for orthopaedics. Cite this article:
We obtained pre-operative and six-month post-operative
Oxford hip (OHS) and knee scores (OKS) for 1523 patients who underwent
total hip replacement and 1784 patients who underwent total knee
replacement. They all also completed a six-month satisfaction question. Scatter plots showed no relationship between pre-operative Oxford
scores and six-month satisfaction scores. Spearman’s rank correlation
coefficients were -0.04 (95% confidence interval (CI) -0.09 to 0.01)
between OHS and satisfaction and 0.04 (95% CI -0.01 to 0.08) between
OKS and satisfaction. A receiver operating characteristic (ROC) curve
analysis was used to identify a cut-off point for the pre-operative
OHS/OKS that identifies whether or not a patient is satisfied with
surgery. We obtained an area under the ROC curve of 0.51 (95% CI
0.45 to 0.56) for hip replacement and 0.56 (95% CI 0.51 to 0.60)
for knee replacement, indicating that pre-operative Oxford scores
have no predictive accuracy in distinguishing satisfied from dissatisfied
patients. In the NHS widespread attempts are being made to use patient-reported
outcome measures (PROMs) data for the purpose of prioritising patients
for surgery. Oxford hip and knee scores have no predictive accuracy
in relation to post-operative patient satisfaction. This evidence
does not support their current use in prioritising access to care.
The purpose of this study was to measure the
radiological parameters of femoral component alignment of the Oxford
Phase 3 unicompartmental knee replacement (UKR), and evaluate their
effect on clinical outcome. Multiple regression analysis was used
to examine the relative contributions of the radiological assessment
of femoral component alignment in 189 consecutive UKRs performed
by a single surgeon. The American Knee Society scores were compared
between groups, defined as being within or outside recommended tolerances
of the position of the femoral component. For the flexion/extension
position 21 UKRs (11.1%) lay outside the recommended limits, and for
posterior overhang of the femoral component nine (4.8%) lay outside
the range. The pre-operative hip/knee/ankle (HKA) angle, narrowest
canal distance from the distal femoral entry point of the alignment
jig and coronal entry-point position had significant effects on
the flexion/extension position. Pre-operative HKA angle had a significant
influence on posterior overhang of the femoral component. However,
there was no significant difference in American Knee Society scores
relative to the position of the femoral component.
Smart trials are total knee tibial trial liners
with load bearing and alignment sensors that will graphically show quantitative
compartment load-bearing forces and component track patterns. These
values will demonstrate asymmetrical ligament balancing and misalignments
with the medial retinaculum temporarily closed. Currently surgeons
use feel and visual estimation of imbalance to assess soft-tissue
balancing and tracking with the medial retinaculum open, which results
in lower medial compartment loads and a wider anteroposterior tibial
tracking pattern. The sensor trial will aid the total knee replacement
surgeon in performing soft-tissue balancing by providing quantitative
visual feedback of changes in forces while performing the releases
incrementally. Initial experience using a smart tibial trial is
presented.
We compared thromboembolic events, major haemorrhage
and death after knee replacement in patients receiving either aspirin
or low-molecular-weight heparin (LMWH). Data from the National Joint
Registry for England and Wales were linked to an administrative
database of hospital admissions in the English National Health Service.
A total of 156 798 patients between April 2003 and September 2008
were included and followed for 90 days. Multivariable risk modelling
was used to estimate odds ratios adjusted for baseline risk factors
(AOR). An AOR <
1 indicates that risk rates are lower with LMWH
than with aspirin. In all, 36 159 patients (23.1%) were prescribed aspirin
and 120 639 patients (76.9%) were prescribed LMWH. We found no statistically
significant differences between the aspirin and LMWH groups in the
rate of pulmonary embolism (0.49% These results should be considered when the existing guidelines
for thromboprophylaxis after knee replacement are reviewed.
Obesity is an epidemic across both the developed
and developing nations that is possibly the most important current
public health factor affecting the morbidity and mortality of the global
population. Obese patients have the potential to pose several challenges
for arthroplasty surgeons from the standpoint of the influence obesity
has on osteoarthritic symptoms, their peri-operative medical management,
the increased intra-operative technical demands on the surgeon,
the intra- and post-operative complications, the long term outcomes
of total hip and knee arthroplasty. Also, there is no consensus
on the role the arthroplasty surgeon should have in facilitating
weight loss for these patients, nor whether obesity should affect
the access to arthroplasty procedures.
We performed a systematic review and meta-analysis
to compare the efficacy of intermittent mechanical compression combined
with pharmacological thromboprophylaxis, against either mechanical
compression or pharmacological prophylaxis in preventing deep-vein
thrombosis (DVT) and pulmonary embolism in patients undergoing hip
or knee replacement. A total of six randomised controlled trials,
evaluating a total of 1399 patients, were identified. In knee arthroplasty,
the rate of DVT was reduced from 18.7% with anticoagulation alone
to 3.7% with combined modalities (risk ratio (RR) 0.27, p = 0.03;
number needed to treat: seven). There was moderate, albeit non-significant,
heterogeneity (I2 = 42%). In hip replacement, there was
a non-significant reduction in DVT from 8.7% with mechanical compression
alone to 7.2% with additional pharmacological prophylaxis (RR 0.84)
and a significant reduction in DVT from 9.7% with anticoagulation
alone to 0.9% with additional mechanical compression (RR 0.17, p
<
0.001; number needed to treat: 12), with no heterogeneity (I2 =
0%). The included studies had insufficient power to demonstrate
an effect on pulmonary embolism. We conclude that the addition of intermittent mechanical leg
compression augments the efficacy of anticoagulation in preventing
DVT in patients undergoing both knee and hip replacement. Further
research on the role of combined modalities in thromboprophylaxis
in joint replacement and in other high-risk situations, such as fracture
of the hip, is warranted.
The treatment of infected nonunions is difficult.
Antibiotic cement-coated (ACC) rods provide stability as well as delivering
antibiotics. We conducted a review of 110 infected nonunions treated
with ACC rods. Patients were divided into two groups: group A (67
patients) with an infected arthrodesis, and group B (43 patients)
with an infected nonunion in a long bone. In group A, infected arthrodesis,
the success rate after the first procedure was 38/67 (57%), 29/67
(43%) required further surgery for either control of infection or
non-union. At last follow-up, five patients required amputation,
representing a limb salvage rate of 62/67 (93%) overall. In all,
29/67 (43%) presented with a bone defect with a mean size of 6.78
cm (2 to 25). Of those with a bone defect, 13/29 (45%) required
further surgery and had a mean size of defect of 7.2 cm (3.5 to
25). The cultures were negative in 17/67 (26%) and the most common
organism cultured was methicillin-resistant Cite this article:
Medium-term survivorship of the Oxford phase
3 unicompartmental knee replacement (UKR) has not yet been established
in an Asian population. We prospectively evaluated the outcome of
400 phase 3 Oxford UKRs in 320 Korean patients with a mean age at
the time of operation of 69 years (48 to 82). The mean follow-up
was 5.2 years (1 to 10). Clinical and radiological assessment was
carried out pre- and post-operatively. At five years, the mean Knee
Society knee and functional scores had increased significantly from
56.2 (30 to 91) pre-operatively to 87.2 (59 to 98) (p = 0.034) and
from 59.2 (30 to 93) to 88.3 (50 to 100) (p = 0.021), respectively.
The Oxford knee score increased from a mean of 25.8 (12 to 39) pre-operatively
to 39.8 (25 to 58) at five years (p = 0.038). The ten-year survival
rate was 94% (95% confidence interval 90.1 to 98.0). A total of
14 UKRs (3.5%) required revision. The most common reason for revision
was dislocation of the bearing in 12 (3%). Conversion to a total
knee replacement was required in two patients who developed osteoarthritis
of the lateral compartment. This is the largest published series of UKR in Korean patients.
It shows that the mid-term results after a minimally invasive Oxford
phase 3 UKR can yield satisfactory clinical and functional results
in this group of patients.
The August 2014 Research Roundup360 looks at: Antibiotic loaded ceramic of use in osteomyelitis; fibronectin implicated in cartilage degeneration; Zinc Chloride accelerates fracture healing in rats; advertisements and false claims; Net Promoter Score: substance or rhetoric?; aspirin for venous thromboembolism prophylaxis and dissection, stress and the soul.
This prospective study describes the outcome of the first 1000 phase 3 Oxford medial unicompartmental knee replacements (UKRs) implanted using a minimally invasive surgical approach for the recommended indications by two surgeons and followed up independently. The mean follow-up was 5.6 years (1 to 11) with 547 knees having a minimum follow-up of five years. At five years their mean Oxford knee score was 41.3 ( The incidence of implant-related re-operations was 2.9%; of these 29 re-operations two were revisions requiring revision knee replacement components with stems and wedges, 17 were conversions to a primary total knee replacement, six were open reductions for dislocation of the bearing, three were secondary lateral UKRs and one was revision of a tibial component. The most common reason for further surgical intervention was progression of arthritis in the lateral compartment (0.9%), followed by dislocation of the bearing (0.6%) and revision for unexplained pain (0.6%). If all implant-related re-operations are considered failures, the ten-year survival rate was 96% (95% confidence interval, 92.5 to 99.5). If only revisions requiring revision components are considered failures the ten-year survival rate is 99.8% (confidence interval 99 to 100). This is the largest published series of UKRs implanted through a minimally invasive surgical approach and with ten-year survival data. The survival rates are similar to those obtained with a standard open approach whereas the function is better. This demonstrates the effectiveness and safety of a minimally invasive surgical approach for implanting the Oxford UKR.
The February 2013 Children’s orthopaedics Roundup360 looks at: ABC treated with suction and curettage; peri-acetabular osteotomy; cast index; Perthes’ disease associated with accidental injury; brachial plexus birth palsy; MRI assessment of DDH; total meniscectomy; and paediatric septic arthritis.
The June 2012 Knee Roundup360 looks at: ACI and mosaicplasty; ACI after microfracture; exercise therapy and the degenerate medial meniscal tear; intra-articular bupivacaine or ropivacaine at knee arthroscopy; lateral trochlear inclination and patellofemoral osteoarthritis; bone loss and ACL reconstruction; assessing stability using the contralateral knee; tranexamic acid and a useful review of knee replacement.
Current analysis of unicondylar knee replacements
(UKRs) by national registries is based on the pooled results of medial
and lateral implants. Consequently, little is known about the differential
performance of medial and lateral replacements and the influence
of each implant type within these pooled analyses. Using data from
the National Joint Registry for England and Wales (NJR) we aimed
to determine the proportion of UKRs implanted on the lateral side
of the knee, and their survival and reason for failure compared
with medial UKRs. By combining information on the side of operation
with component details held on the NJR, we were able to determine
implant laterality (medial
The February 2013 Knee Roundup360 looks at: mobile-bearing TKRs; arthroscopic ACL reconstruction; the use of chondrocytes for osteochondral defects; ACL reconstruction and the return to pivoting sports; ACLs and the MOON study; the benefit of knee navigation; and trabecular metal.
The objective of this study is to determine an optimal antibiotic-loaded
bone cement (ALBC) for infection prophylaxis in total joint arthroplasty
(TJA). We evaluated the antibacterial effects of polymethylmethacrylate
(PMMA) bone cements loaded with vancomycin, teicoplanin, ceftazidime,
imipenem, piperacillin, gentamicin, and tobramycin against methicillin-sensitive Objectives
Methods
The significance of weight in the indications
for unicompartmental knee replacement (UKR) is unclear. Our hypothesis was
that weight does not affect the long-term rate of survival of UKRs. We undertook a retrospective study of 212 UKRs at a mean follow-up
of 12 years (7 to 22). The patients were distributed according to
body mass index (BMI; <
The ten-year rates of survival were similar in the two weight
subgroups (≥ 82 kg: 93.5% (95% confidence interval (CI) 66.5 to
96.3); <
82 kg: 92.5% (95% CI 82.5 to 94.1)) and also in the
two BMI subgroups (≥ 30 kg/m2: 92% (95% CI 82.5 to 95.3);
<
30 kg/m2: 94% (95% CI 78.4 to 95.9)). Multimodal
regression analysis revealed that weight plays a part in reducing
the risk of revision with a relative risk of 0.387, although this
did not reach statistical significance (p = 0.662). The results
relating weight and BMI to the clinical outcome were not statistically
significant. Thus, this study confirms that weight does not influence
the long-term rate of survival of UKR. Cite this article: