Unicompartmental knee arthroplasty (UKA) is a potential treatment
for isolated bone on bone osteoarthritis when limited to a single
compartment. The risk for revision of UKA is three times higher
than for total knee arthroplasty (TKA). The aim of this review was
to discuss the different revision options after UKA failure. A search was performed for English language articles published
between 2006 and 2016. After reviewing titles and abstracts, 105
papers were selected for further analysis. Of these, 39 papers were
deemed to contain clinically relevant data to be included in this review.Objectives
Materials and Methods
Knee joint distraction (KJD) is a relatively new, knee-joint
preserving procedure with the goal of delaying total knee arthroplasty
(TKA) in young and middle-aged patients. We present a randomised
controlled trial comparing the two. The 60 patients ≤ 65 years with end-stage knee osteoarthritis
were randomised to either KJD (n = 20) or TKA (n = 40). Outcomes
were assessed at baseline, three, six, nine, and 12 months. In the
KJD group, the joint space width (JSW) was radiologically assessed,
representing a surrogate marker of cartilage thickness.Aims
Patients and Methods
Up to 40% of unicompartmental knee arthroplasty (UKA) revisions are performed for unexplained pain which may be caused by elevated proximal tibial bone strain. This study investigates the effect of tibial component metal backing and polyethylene thickness on bone strain in a cemented fixed-bearing medial UKA using a finite element model (FEM) validated experimentally by digital image correlation (DIC) and acoustic emission (AE). A total of ten composite tibias implanted with all-polyethylene (AP) and metal-backed (MB) tibial components were loaded to 2500 N. Cortical strain was measured using DIC and cancellous microdamage using AE. FEMs were created and validated and polyethylene thickness varied from 6 mm to 10 mm. The volume of cancellous bone exposed to < -3000 µε (pathological loading) and < -7000 µε (yield point) minimum principal (compressive) microstrain and > 3000 µε and > 7000 µε maximum principal (tensile) microstrain was computed.Objectives
Materials and Methods
To compare the gait of unicompartmental knee arthroplasty (UKA)
and total knee arthroplasty (TKA) patients with healthy controls,
using a machine-learning approach. 145 participants (121 healthy controls, 12 patients with cruciate-retaining
TKA, and 12 with mobile-bearing medial UKA) were recruited. The
TKA and UKA patients were a minimum of 12 months post-operative,
and matched for pattern and severity of arthrosis, age, and body
mass index. Participants walked on an instrumented treadmill until their
maximum walking speed was reached. Temporospatial gait parameters,
and vertical ground reaction force data, were captured at each speed.
Oxford knee scores (OKS) were also collected. An ensemble of trees
algorithm was used to analyse the data: 27 gait variables were used
to train classification trees for each speed, with a binary output
prediction of whether these variables were derived from a UKA or
TKA patient. Healthy control gait data was then tested by the decision
trees at each speed and a final classification (UKA or TKA) reached
for each subject in a majority voting manner over all gait cycles
and speeds. Top walking speed was also recorded.Aims
Patients and Methods
Since redesign of the Oxford phase III mobile-bearing unicompartmental
knee arthroplasty (UKA) femoral component to a twin-peg design,
there has not been a direct comparison to total knee arthroplasty
(TKA). Thus, we explored differences between the two cohorts. A total of 168 patients (201 knees) underwent medial UKA with
the Oxford Partial Knee Twin-Peg. These patients were compared with
a randomly selected group of 177 patients (189 knees) with primary
Vanguard TKA. Patient demographics, Knee Society (KS) scores and
range of movement (ROM) were compared between the two cohorts. Additionally,
revision, re-operation and manipulation under anaesthesia rates
were analysed.Aims
Patients and Methods
The interest in unicompartmental knee arthroplasty (UKA) for
medial osteoarthritis has increased rapidly but the long-term follow-up
of the Oxford UKAs has yet to be analysed in non-designer centres.
We have examined our ten- to 15-year clinical and radiological follow-up
data for the Oxford Phase III UKAs. Between January 1999 and January 2005 a total of 138 consecutive
Oxford Phase III arthroplasties were performed by a single surgeon
in 129 patients for medial compartment osteoarthritis (71 right
and 67 left knees, mean age 72.0 years (47 to 91), mean body mass
index 28.2 (20.7 to 52.2)). Both clinical data and radiographs were
prospectively recorded and obtained at intervals. Of the 129 patients,
32 patients (32 knees) died, ten patients (12 knees) were not able
to take part in the final clinical and radiological assessment due
to physical and mental conditions, but via telephone interview it
was confirmed that none of these ten patients (12 knees) had a revision
of the knee arthroplasty. One patient (two knees) was lost to follow-up.Aims
Patients and Methods
An evidence-based radiographic Decision Aid for meniscal-bearing
unicompartmental knee arthroplasty (UKA) has been developed and
this study investigates its performance at an independent centre. Pre-operative radiographs, including stress views, from a consecutive
cohort of 550 knees undergoing arthroplasty (UKA or total knee arthroplasty;
TKA) by a single-surgeon were assessed. Suitability for UKA was
determined using the Decision Aid, with the assessor blinded to
treatment received, and compared with actual treatment received, which
was determined by an experienced UKA surgeon based on history, examination,
radiographic assessment including stress radiographs, and intra-operative
assessment in line with the recommended indications as described
in the literature.Aims
Patients and Methods
The objective of this study was to determine if the use of fascia lata as a tendon regeneration guide (placed into the tendon canal following harvesting the semitendinosus tendon) would improve the incidence of tissue regeneration and prevent fatty degeneration of the semitendinosus muscle. Bilateral semitendinosus tendons were harvested from rabbits using a tendon stripper. On the inducing graft (IG) side, the tendon canal and semitendinosus tibial attachment site were connected by the fascia lata, which was harvested at the same width as the semitendinosus tendon. On the control side, no special procedures were performed. Two groups of six rabbits were killed at post-operative weeks 4 and 8, respectively. In addition, three healthy rabbits were killed to obtain normal tissue. We evaluated the incidence of tendon tissue regeneration, cross-sectional area of the regenerated tendon tissue and proportion of fatty tissue in the semitendinosus muscle.Objectives
Materials and Methods
The role of arthroscopy in the treatment of soft-tissue
injuries associated with proximal tibial fractures remains debatable.
Our hypothesis was that MRI over-diagnoses clinically relevant associated
soft-tissue injuries. This prospective study involved 50 consecutive
patients who underwent surgical treatment for a split-depression fracture
of the lateral tibial condyle (AO/OTA type B3.1). The mean age of
patients was 50 years (23 to 86) and 27 (54%) were female. All patients
had MRI and arthroscopy. Arthroscopy identified 12 tears of the
lateral meniscus, including eight bucket-handle tears that were
sutured and four that were resected, as well as six tears of the
medial meniscus, of which five were resected. Lateral meniscal injuries
were diagnosed on MRI in four of 12 patients, yielding an overall
sensitivity of 33% (95% confidence interval (CI) 11 to 65). Specificity
was 76% (95% CI 59 to 88), with nine tears diagnosed among 38 menisci
that did not contain a tear. MRI identified medial meniscal injuries
in four of six patients, yielding an overall sensitivity of 67%
(95% CI 24 to 94). Specificity was 66% (95% CI 50 to 79), with 15
tears diagnosed in 44 menisci that did not contain tears. MRI appears to offer only a marginal benefit as the specificity
and sensitivity for diagnosing meniscal injuries are poor in patients
with a fracture. There were fewer arthroscopically-confirmed associated
lesions than reported previously in MRI studies. Cite this article:
We have shown in a previous study that patients with combined lesions of the anterior cruciate (ACL) and medial collateral ligaments (MCL) had similar anteroposterior (AP) but greater valgus laxity at 30° after reconstruction of the ACL when compared with patients who had undergone reconstruction of an isolated ACL injury. The present study investigated the same cohort of patients after a minimum of three years to evaluate whether the residual valgus laxity led to a poorer clinical outcome. Each patient had undergone an arthroscopic double-bundle ACL reconstruction using a semitendinosus-gracilis graft. In the combined ACL/MCL injury group, the grade II medial collateral ligament injury was not treated. At follow-up, AP laxity was measured using a KT-2000 arthrometer, while valgus laxity was evaluated with Telos valgus stress radiographs and compared with the uninjured knee. We evaluated clinical outcome scores, muscle girth and time to return to activities for the two groups. Valgus stress radiographs showed statistically significant greater mean medial joint opening in the reconstructed compared with the uninjured knees (1.7 mm (
There is a large amount of evidence available
about the relative merits of unicompartmental and total knee arthroplasty
(UKA and TKA). Based on the same evidence, different people draw
different conclusions and as a result, there is great variability
in the usage of UKA. The revision rate of UKA is much higher than TKA and so some
surgeons conclude that UKA should not be performed. Other surgeons
believe that the main reason for the high revision rate is that
UKA is easy to revise and, therefore, the threshold for revision
is low. They also believe that UKA has many advantages over TKA
such as a faster recovery, lower morbidity and mortality and better
function. They therefore conclude that UKA should be undertaken
whenever appropriate. The solution to this argument is to minimise the revision rate
of UKA, thereby addressing the main disadvantage of UKA. The evidence
suggests that this will be achieved if surgeons use UKA for at least
20% of their knee arthroplasties and use implants that are appropriate
for these broad indications. Cite this article:
The June 2015 Research Roundup360 looks at: Tranexamic acid: just give it – it’s not important how!; The anterolateral ligament re-examined; Warfarin a poor post-operative agent; Passive exoskeleton the orthosis of the future?; Musculoskeletal medicine: a dark art to UK medical students?; Alendronic acid and bone density post arthroplasty; Apples with oranges? Knee functional scores revisited
Mobile-bearing unicompartmental knee replacements
(UKRs) with a flat tibial plateau have not performed well in the
lateral compartment, owing to a high dislocation rate. This led
to the development of the Domed Lateral Oxford UKR (Domed OUKR)
with a biconcave bearing. The aim of this study was to assess the
survival and clinical outcomes of the Domed OUKR in a large patient
cohort in the medium term. We prospectively evaluated 265 consecutive knees with isolated
disease of the lateral compartment and a mean age at surgery of
64 years (32 to 90). At a mean follow-up of four years ( The Domed Lateral OUKR gives good clinical outcomes, low re-operation
and revision rates and a low dislocation rate in patients with isolated
lateral compartmental disease, in the hands of the designer surgeons. Cite this article:
This prospective study reports the 15-year survival and ten-year
functional outcome of a consecutive series of 1000 minimally invasive
Phase 3 Oxford medial UKAs (818 patients, 393 men, 48%, 425 women,
52%, mean age 66 years; 32 to 88). These were implanted by two surgeons
involved with the design of the prosthesis to treat anteromedial
osteoarthritis and spontaneous osteonecrosis of the knee, which
are recommended indications. Patients were prospectively identified
and followed up independently for a mean of 10.3 years (5.3 to 16.6). At ten years, the mean Oxford Knee Score was 40 (standard deviation
( This is the only large series of minimally invasive UKAs with
15-year survival data. The results support the continued use of
minimally invasive UKA for the recommended indications. Cite this article:
The June 2015 Children’s orthopaedics Roundup360 looks at: ACL reconstruction in paediatric knees; Hips, slips and cams; The adolescent clavicle; 3D fluoroscopy in DDH?; The psychiatric aspects of hip pain in adolescents; Adolescent bunions: dealer’s choice?; Medial epicondylar fractures revisited
The anatomy and microstructure of the menisci
allow the effective distribution of load across the knee. Meniscectomy
alters the biomechanical environment and is a potent risk factor
for osteoarthritis. Despite a trend towards meniscus-preserving
surgery, many tears are irreparable, and many repairs fail. Meniscal allograft transplantation has principally been carried
out for pain in patients who have had a meniscectomy. Numerous case
series have reported a significant improvement in patient-reported
outcomes after surgery, but randomised controlled trials have not
been undertaken. It is scientifically plausible that meniscal allograft transplantation
is protective of cartilage, but this has not been established clinically
to date. Cite this article:
The April 2015 Knee Roundup360 looks at: Genetic determinants of ACL strength; TKA outcomes influenced by prosthesis; Single- or two-stage revision for infected TKA?; Arthroscopic meniscectomy: a problem that just won’t go away!; Failure in arthroscopic ACL reconstruction; ACL reconstruction in the over 50s?; Knee arthroplasty for early osteoarthritis; All inside meniscal repair; Steroids, thrombogenic markers and TKA
