Total knee arthroplasty (TKA) is a cost effective
and extremely successful operation. As longevity increases, the demand
for primary TKA will continue to rise. The success and survivorship
of TKAs are dependent on the demographics of the patient, surgical
technique and implant-related factors. Currently the risk of failure of a TKA requiring revision surgery
ten years post-operatively is 5%. The most common indications for revision include aseptic loosening
(29.8%), infection (14.8%), and pain (9.5%). Revision surgery poses
considerable clinical burdens on patients and financial burdens
on healthcare systems. We present a current concepts review on the epidemiology of failed
TKAs using data from worldwide National Joint Registries. Cite this article:
Unicompartmental knee arthroplasty (UKA) has
advantages over total knee arthroplasty but national joint registries report
a significantly higher revision rate for UKA. As a result, most
surgeons are highly selective, offering UKA only to a small proportion
(up to 5%) of patients requiring arthroplasty of the knee, and consequently
performing few each year. However, surgeons with large UKA practices
have the lowest rates of revision. The overall size of the practice
is often beyond the surgeon’s control, therefore case volume may
only be increased by broadening the indications for surgery, and
offering UKA to a greater proportion of patients requiring arthroplasty
of the knee. The aim of this study was to determine the optimal UKA usage
(defined as the percentage of knee arthroplasty practice comprised
by UKA) to minimise the rate of revision in a sample of 41 986 records
from the for National Joint Registry for England and Wales (NJR). UKA usage has a complex, non-linear relationship with the rate
of revision. Acceptable results are achieved with the use of 20%
or more. Optimal results are achieved with usage between 40% and
60%. Surgeons with the lowest usage (up to 5%) have the highest
rates of revision. With optimal usage, using the most commonly used
implant, five-year survival is 96% (95% confidence interval (CI)
94.9 to 96.0), compared with 90% (95% CI 88.4 to 91.6) with low
usage (5%) previously considered ideal. The rate of revision of UKA is highest with low usage, implying
the use of narrow, and perhaps inappropriate, indications. The widespread
use of broad indications, using appropriate implants, would give
patients the advantages of UKA, without the high rate of revision. Cite this article:
This is the second of a series of reviews of registries. This review looks specifically at worldwide registry data that have been collected on knee arthroplasty, what we have learned from their reports, and what the limitations are as to what we currently know.
Partial knee arthroplasty (PKA), either medial
or lateral unicompartmental knee artroplasty (UKA) or patellofemoral arthroplasty
(PFA) are a good option in suitable patients and have the advantages
of reduced operative trauma, preservation of both cruciate ligaments
and bone stock, and restoration of normal kinematics within the
knee joint. However, questions remain concerning long-term survival.
The goal of this review article was to present the long-term results
of medial and lateral UKA, PFA and combined compartmental arthroplasty
for multicompartmental disease. Medium- and long-term studies suggest
reasonable outcomes at ten years with survival greater than 95% in
UKA performed for medial osteoarthritis or osteonecrosis, and similarly
for lateral Cite this article:
The June 2015 Hip &
Pelvis Roundup360 looks at: neuraxial anaesthesia and large joint arthroplasty; revision total hip arthoplasty: factors associated with re-revision surgery; acetabular version and clinical outcomes in impingement surgery; hip precautions may be ineffective; implant selection and cost effectiveness; femoroacetabular impingement in the older age group; multiple revision in hip arthroplasty
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 June 2015 Knee Roundup360 looks at: Cruciate substituting
Previous studies from single centres or single-surgeon
series report good early and mid-term results for high tibial osteotomy
(HTO) in the treatment of osteoarthritis of the knee. However, the
survivorship of HTO at a national level is unknown. This registry-based
study included 3195 high HTOs performed between 1987 and 2008. Kaplan-Meier analysis
revealed an overall survivorship of 89% (95% confidence interval
(CI) 88 to 90) at five years and 73% (95% CI 72 to 75) at ten years,
when conversion to total knee replacement was taken as the endpoint.
Females and patients aged >
50 years had worse survivorship than
males or patients aged ≤ 50 years (hazard ratio (HR) 1.26 (95% CI
1.11 to 1.43) and HR 1.41 (95% CI 1.23 to 1.64), respectively).
The survivorship of HTOs performed between 1998 to 2008 was worse
than for those performed between 1987 and 1997.
The common recommended treatment for infected
total hip replacement is two-staged exchange including removal of
all components. However, removal of well-fixed femoral stems can
result in structural bone damage. We recently reported on an alternative
treatment of partial two-stage exchange used in selected cases,
in which a well-fixed femoral stem was left and only the acetabular
component removed, the joint space was debrided thoroughly, an antibiotic-laden
polymethylmethacrylate spacer was moulded using a bulb-type syringe
and placed in the acetabulum, intravenous antibiotics were administered
during the interval, and delayed re-implantation was performed.
In 19 patients treated with this technique from January 2000 to
January 2011, 89% were free of infection at a mean follow-up of
four years (2 to 11). Since then, disposable silicone moulds have
become available to fabricate spacers in separate femoral and head
units. The head spacer mould, which incorporates various neck taper adapter
options, greatly facilitates the technique of partial two-stage
exchange. We report our early experience using disposable silicone
head spacer moulds for partial two-stage exchange in seven patients
with infected primary hip replacements. Cite this article:
Advances in the treatment of periprosthetic joint
infections of the hip have once more pushed prosthesis preserving techniques
into the limelight. At the same time, the common infecting organisms
are evolving to become more resistant to conventional antimicrobial
agents. Whilst the epidemiology of resistant staphylococci is changing,
a number of recent reports have advocated the use of irrigation
and debridement and one-stage revision for the treatment of periprosthetic
joint infections due to resistant organisms. This review presents
the available evidence for the treatment of periprosthetic joint
infections of the hip, concentrating in particular on methicillin
resistant staphylococci. Cite this article:
Previous studies of failure mechanisms leading
to revision total knee replacement (TKR) performed between 1986 and
2000 determined that many failed early, with a disproportionate
amount accounted for by infection and implant-associated factors
including wear, loosening and instability. Since then, efforts have
been made to improve implant performance and instruct surgeons in
best practice. Recently our centre participated in a multi-centre evaluation
of 844 revision TKRs from 2010 to 2011. The purpose was to report
a detailed analysis of failure mechanisms over time and to see if
failure modes have changed over the past 10 to 15 years. Aseptic
loosening was the predominant mechanism of failure (31.2%), followed
by instability (18.7%), infection (16.2%), polyethylene wear (10.0%),
arthrofibrosis (6.9%) and malalignment (6.6%). The mean time to
failure was 5.9 years (ten days to 31 years), 35.3% of all revisions
occurred at less than two years, and 60.2% in the first five years.
With improvements in implant and polyethylene manufacture, polyethylene
wear is no longer a leading cause of failure. Early mechanisms of
failure are primarily technical errors. In addition to improving
implant longevity, industry and surgeons must work together to decrease
these technical errors. All reports on failure of TKR contain patients
with unexplained pain who not infrequently have unmet expectations.
Surgeons must work to achieve realistic patient expectations pre-operatively,
and therefore, improve patient satisfaction post-operatively. Cite this article:
Degenerative problems of the hip in patients
with childhood and adult onset neuromuscular disorders can be challenging
to treat. Many orthopaedic surgeons are reluctant to recommend total
hip replacement (THR) for patients with underlying neuromuscular
disorders due to the perceived increased risks of dislocation, implant loosening,
and lack of information about the functional outcomes and potential
benefits of these procedures in these patients. Modular femoral
components and alternative bearings which facilitate the use of
large femoral heads, constrained acetabular components and perhaps
more importantly, a better understanding about the complications
and outcomes of THR in the patient with neuromuscular disorders,
make this option viable. This paper will review the current literature
and our experience with THR in the more frequently encountered neuromuscular
disorders. Cite this article:
The October 2014 Hip &
Pelvis Roundup360 looks at: functional acetabular orientation; predicting re-admission following THR; metal ions and resurfacing; lipped liners increase stability; all anaesthetics equal in hip fracture surgery; revision hip surgery in very young patients; and uncemented hips.
The December 2014 Knee Roundup360 looks at: national guidance on arthroplasty thromboprophylaxis is effective; unicompartmental knee replacement has the edge in terms of short-term complications; stiff knees, timing and manipulation; neuropathic pain and total knee replacement; synovial fluid α-defensin and CRP: a new gold standard in joint infection diagnosis?; how to assess anterior knee pain?; where is the evidence? Five new implants under the spotlight; and a fresh look at ACL reconstruction
Despite a lack of long-term follow-up, there
is an increasing trend towards using femoral heads of large diameter
in total hip replacement (THR), partly because of the perceived
advantage of lower rates of dislocation. However, increasing the
size of the femoral head is not the only way to reduce the rate
of dislocation; optimal alignment of the components and repair of
the posterior capsule could achieve a similar effect. In this prospective study of 512 cemented unilateral THRs (Male:Female
230:282) performed between 2004 and 2011, we aimed to determine
the rate of dislocation in patients who received a 22 mm head on
a 9/10 Morse taper through a posterior approach with capsular repair
and using the transverse acetabular ligament (TAL) as a guide for the
alignment of the acetabular component. The mean age of the patients
at operation was 67 years (35 to 89). The mean follow-up was 2.8
years (0.5 to 6.6). Pre- and post-operative assessment included
Oxford hip, Short Form-12 and modified University of California
Los Angeles and Merle D’Aubigne scores. The angles of inclination
and anteversion of the acetabular components were measured using
radiological software. There were four dislocations (0.78%), all
of which were anterior. In conclusion, THR with a 22 mm diameter head performed through
a posterior approach with capsular repair and using the TAL as a
guide for the alignment of the acetabular component was associated
with a low rate of dislocation. Cite this article:
Using data from the Norwegian Hip Fracture Register,
8639 cemented and 2477 uncemented primary hemiarthroplasties for
displaced fractures of the femoral neck in patients aged > 70 years
were included in a prospective observational study. A total of 218
re-operations were performed after cemented and 128 after uncemented
procedures. Survival of the hemiarthroplasties was calculated using
the Kaplan-Meier method and hazard rate ratios (HRR) for revision
were calculated using Cox regression analyses. At five years the
implant survival was 97% (95% confidence interval (CI) 97 to 97)
for cemented and 91% (95% CI 87 to 94) for uncemented hemiarthroplasties.
Uncemented hemiarthroplasties had a 2.1 times increased risk of
revision compared with cemented prostheses (95% confidence interval
1.7 to 2.6, p < 0.001). The increased risk was mainly caused
by revisions for peri-prosthetic fracture (HRR = 17), aseptic loosening
(HRR = 17), haematoma formation (HRR = 5.3), superficial infection
(HRR = 4.6) and dislocation (HRR = 1.8). More intra-operative complications,
including intra-operative death, were reported for the cemented
hemiarthroplasties. However, in a time-dependent analysis, the HRR
for re-operation in both groups increased as follow-up increased. This study showed that the risk for revision was higher for uncemented
than for cemented hemiarthroplasties.
Haematomas, drainage, and other non-infectious
wound complications following total knee replacement (TKR) have
been associated with long-term sequelae, in particular, deep infection.
However, the impact of these wound complications on clinical outcome
is unknown. This study compares results in 15 patients re-admitted
for wound complications within 90 days of TKR to 30 matched patients
who underwent uncomplicated total knee replacements. Patients with
wound complications had a mean age of 66 years (49 to 83) and mean
body mass index (BMI) of 37 (21 to 54), both similar to that of
patients without complications (mean age 65 years and mean BMI 35). Those
with complications had lower mean Knee Society function scores (46
(0 to 100 Cite this article:
The April 2014 Hip & Pelvis Roundup360 looks at: Recent arthroplasty and flight; whether that squeak could be a fracture; diagnosing early infected hip replacement; impaction grafting at a decade; whether squeaking is more common than previously thought; femoral offset associated with post THR outcomes; and periprosthetic fracture stabilisation.