Minimally invasive total knee replacement (MIS-TKR)
has been reported to have better early recovery than conventional
TKR. Quadriceps-sparing (QS) TKR is the least invasive MIS procedure,
but it is technically demanding with higher reported rates of complications
and outliers. This study was designed to compare the early clinical
and radiological outcomes of TKR performed by an experienced surgeon
using the QS approach with or without navigational assistance (NA),
or using a mini-medial parapatellar (MP) approach. In all, 100 patients
completed a minimum two-year follow-up: 30 in the NA-QS group, 35
in the QS group, and 35 in the MP group. There were no significant
differences in clinical outcome in terms of ability to perform a
straight-leg raise at 24 hours (p = 0.700), knee score (p = 0.952),
functional score (p = 0.229) and range of movement (p = 0.732) among
the groups. The number of outliers for all three radiological parameters
of mechanical axis, frontal femoral component alignment and frontal
tibial component alignment was significantly lower in the NA-QS
group than in the QS group (p = 0.008), but no outlier was found
in the MP group. In conclusion, even after the surgeon completed a substantial
number of cases before the commencement of this study, the supplementary
intra-operative use of computer-assisted navigation with QS-TKR
still gave inferior radiological results and longer operating time,
with a similar outcome at two years when compared with a MP approach. Cite this article:
In this study we randomised 140 patients who
were due to undergo primary total knee arthroplasty (TKA) to have the
procedure performed using either patient-specific cutting guides
(PSCG) or conventional instrumentation (CI). . The primary outcome measure was the mechanical axis, as measured
at three months on a standing long-leg radiograph by the hip–knee–ankle
(HKA) angle. This was undertaken by an independent observer who
was blinded to the instrumentation. Secondary outcome measures were
component positioning, operating time, Knee Society and Oxford knee
scores, blood loss and length of hospital stay. A total of 126 patients (67 in the CI group and 59 in the PSCG
group) had complete clinical and radiological data. There were 88
females and 52 males with a mean age of 69.3 years (47 to 84) and
a mean BMI of 28.6 kg/m. 2. (20.2 to 40.8). The mean HKA
angle was 178.9° (172.5 to 183.4) in the CI group and 178.2° (172.4
to 183.4) in the PSCG group (p = 0.34).
The aim of this study was to compare the biomechanical models of two frequently used techniques for reconstructing severe acetabular defects with pelvic discontinuity in revision total hip arthroplasty (THA) – the Trabecular Metal Acetabular Revision System (TMARS) and custom triflange acetabular components (CTACs) – using virtual modelling. Pre- and postoperative CT scans from ten patients who underwent revision with the TMARS for a Paprosky IIIB acetabular defect with pelvic discontinuity were retrospectively collated. Computer models of a CTAC implant were designed from the preoperative CT scans of these patients. Computer models of the TMARS reconstruction were segmented from postoperative CT scans using a semi-automated method. The amount of bone removed, the implant-bone apposition that was achieved, and the restoration of the centre of rotation of the hip were compared between all the actual TMARS and the virtual CTAC implants.Aims
Methods
The aim of this study was to evaluate whether achieving medial joint opening, as measured by the change in the joint line convergence angle (∆JLCA), is a better predictor of clinical outcomes after high tibial osteotomy (HTO) compared with the mechanical axis deviation, and to find individualized targets for the redistribution of load that reflect bony alignment, joint laxity, and surgical technique. This retrospective study analyzed 121 knees in 101 patients. Patient-reported outcome measures (PROMs) were collected preoperatively and one year postoperatively, and were analyzed according to the surgical technique (opening or closing wedge), postoperative mechanical axis deviation (deviations above and below 10% from the target), and achievement of medial joint opening (∆JLCA > 1°). Radiological parameters, including JLCA, mechanical axis deviation, and the difference in JLCA between preoperative standing and supine radiographs (JLCAPD), an indicator of medial soft-tissue laxity, were measured. Cut-off points for parameters related to achieving medial joint opening were calculated from receiver operating characteristic (ROC) curves.Aims
Methods
Total knee arthroplasty is an established treatment for knee osteoarthritis with excellent long-term results, but there remains controversy about the role of uncemented prostheses. We present the long-term results of a randomized trial comparing an uncemented tantalum metal tibial component with a conventional cemented component of the same implant design. Patients under the age of 70 years with symptomatic osteoarthritis of the knee were randomized to receive either an uncemented tantalum metal tibial monoblock component or a standard cemented modular component. The mean age at time of recruitment to the study was 63 years (50 to 70), 46 (51.1%) knees were in male patients, and the mean body mass index was 30.4 kg/m2 (21 to 36). The same cruciate retaining total knee system was used in both groups. All patients received an uncemented femoral component and no patients had their patella resurfaced. Patient outcomes were assessed preoperatively and postoperatively using the modified Oxford Knee Score, Knee Society Score, and 12-Item Short-Form Health Survey questionnaire (SF-12) score. Radiographs were analyzed using the American Knee Society Radiograph Evaluation score. Operative complications, reoperations, or revision surgery were recorded. A total of 90 knees were randomized and at last review 77 knees were assessed. In all, 11 patients had died and two were lost to follow-up.Aims
Methods
Hip fractures in patients < 60 years old currently account for only 3% to 4% of all hip fractures in England, but this proportion is increasing. Little is known about the longer-term patient-reported outcomes in this potentially more active population. The primary aim is to examine patient-reported outcomes following isolated hip fracture in patients aged < 60 years. The secondary aim is to determine an association between outcomes and different types of fracture pattern and/or treatment implants. All hip fracture patients aged 18 to 60 years admitted to a single centre over a 15-year period were used to identify the study group. Fracture pattern (undisplaced intracapsular, displaced intracapsular, and extracapsular) and type of operation (multiple cannulated hip screws, angular stable fixation, hemiarthroplasty, and total hip replacement) were recorded. The primary outcome measures were the Oxford Hip Score (OHS), the EuroQol five-dimension questionnaire (EQ-5D-3L), and EQ-visual analogue scale (VAS) scores. Preinjury scores were recorded by patient recall and postinjury scores were collected at a mean of 57 months (9 to 118) postinjury. Ethics approval was obtained prior to study commencement.Aims
Methods
Despite the increase in the surgical repair of proximal hamstring tears, there exists a lack of consensus in the optimal timing for surgery. There is also disagreement on how partial tears managed surgically compare with complete tears repaired surgically. This study aims to compare the mid-term functional outcomes in, and operating time required for, complete and partial proximal hamstring avulsions, that are repaired both acutely and chronically. This is a prospective series of 156 proximal hamstring surgical repairs, with a mean age of 48.9 years (21.5 to 78). Functional outcomes were assessed preinjury, preoperatively, and postoperatively (six months and minimum three years) using the Sydney Hamstring Origin Rupture Evaluation (SHORE) score. Operating time was recorded for every patient.Aims
Methods
A significant percentage of patients remain dissatisfied after total knee arthroplasty (TKA). The aim of this study was to determine whether the sequential addition of accelerometer-based navigation for femoral component preparation and sensor-guided ligament balancing improved complication rates, radiological alignment, or patient-reported outcomes (PROMs) compared with a historical control group using conventional instrumentation. This retrospective cohort study included 371 TKAs performed by a single surgeon sequentially. A historical control group, with the use of intramedullary guides for distal femoral resection and surgeon-guided ligament balancing, was compared with a group using accelerometer-based navigation for distal femoral resection and surgeon-guided balancing (group 1), and one using navigated femoral resection and sensor-guided balancing (group 2). Primary outcome measures were Patient-Reported Outcomes Measurement Information System (PROMIS) and Knee injury and Osteoarthritis Outcome (KOOS) scores measured preoperatively and at six weeks and 12 months postoperatively. The position of the components and the mechanical axis of the limb were measured postoperatively. The postoperative range of motion (ROM), haematocrit change, and complications were also recorded.Aims
Methods
The purpose of this study was to determine the functional outcome and implant survivorship of mobile-bearing total ankle arthroplasty (TAA) performed by a single surgeon. We reviewed 205 consecutive patients (210 ankles) who had undergone mobile-bearing TAA (205 patients) for osteoarthritis of the ankle between January 2005 and December 2015. Their mean follow-up was 6.4 years (2.0 to 13.4). Functional outcome was assessed using the Ankle Osteoarthritis Scale, American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, 36-Item Short-Form Health Survey (SF-36) score, visual analogue scale, and range of movement. Implant survivorship and complications were also evaluated.Aims
Patients and Methods
The primary objective of this study was to compare accuracy in restoring the native centre of hip rotation in patients undergoing conventional manual total hip arthroplasty (THA) This prospective cohort study included 50 patients undergoing conventional manual THA and 25 patients receiving robotic-arm assisted THA. Patients undergoing conventional manual THA and robotic-arm assisted THA were well matched for age (mean age, 69.4 years (Objectives
Materials and Methods
We performed a randomised controlled trial comparing
computer-assisted surgery (CAS) with conventional surgery (CONV)
in total knee replacement (TKR). Between 2009 and 2011 a total of
192 patients with a mean age of 68 years (55 to 85) with osteoarthritis
or arthritic disease of the knee were recruited from four Norwegian
hospitals. At three months follow-up, functional results were marginally
better for the CAS group. Mean differences (MD) in favour of CAS
were found for the Knee Society function score (MD: 5.9, 95% confidence
interval (CI) 0.3 to 11.4, p = 0.039), the Knee Injury and Osteoarthritis
Outcome Score (KOOS) subscales for ‘pain’ (MD: 7.7, 95% CI 1.7 to
13.6, p = 0.012), ‘sports’ (MD: 13.5, 95% CI 5.6 to 21.4, p = 0.001)
and ‘quality of life’ (MD: 7.2, 95% CI 0.1 to 14.3, p = 0.046).
At one-year follow-up, differences favouring CAS were found for
KOOS ‘sports’ (MD: 11.0, 95% CI 3.0 to 19.0, p = 0.007) and KOOS
‘symptoms’ (MD: 6.7, 95% CI 0.5 to 13.0, p = 0.035). The use of
CAS resulted in fewer outliers in frontal alignment (>
3° malalignment),
both for the entire TKR (37.9% Cite this article:
Large femoral heads have become popular in total
hip replacement (THR) as a method of reducing the risk of dislocation.
However, if large heads are used in ceramic-on-ceramic THR, the
liner must be thinner, which may increase the risk of fracture.
To compare the rates of ceramic fracture and dislocation between
28 mm and 32 mm ceramic heads, 120 hips in 109 patients (51 men
and 58 women, mean age 49.2 years) were randomised to THR with either
a 28 mm or a 32 mm ceramic articulation. A total of 57/60 hips assigned
to the 28 mm group and 55/60 hips assigned to the 32 mm group were
followed for at least five years. No ceramic component fractures
occured in any patient in either group. There was one dislocation
in the 32 mm group and none in the 28 mm group (p = 0.464). No hip
had detectable wear, focal osteolysis or prosthetic loosening. In
our small study the 32 mm ceramic articulation appeared to be safe
in terms of ceramic liner fracture. Cite this article:
The aim of this study was to evaluate the effects of using a
portable, accelerometer-based surgical navigation system (KneeAlign2)
in total knee arthroplasty (TKA) on the alignment of the femoral
component, and blood loss. A total of 241 consecutive patients with primary osteoarthritis
of the knee were enrolled in this prospective, randomised controlled
study. There were 207 women and 34 men. The mean age of the patients
was 74.0 years (57 to 89). The KneeAlign2 system was used for distal
femoral resection in 121 patients (KA2 group) and a conventional intramedullary
femoral guide was used in 120 patients (IM group).Aims
Patients and Methods
Patient-specific cutting guides (PSCGs) are designed
to improve the accuracy of alignment of total knee replacement (TKR).
We compared the accuracy of limb alignment and component positioning
after TKR performed using PSCGs or conventional instrumentation.
A total of 80 patients were randomised to undergo TKR with either of
the different forms of instrumentation, and radiological outcomes
and peri-operative factors such as operating time were assessed.
No significant difference was observed between the groups in terms
of tibiofemoral angle or femoral component alignment. Although the
tibial component in the PSCGs group was measurably closer to neutral
alignment than in the conventional group, the size of the difference
was very small (89.8° ( Cite this article:
A high radiographic inclination angle (RI) contributes
to accelerated wear and has been associated with dislocation after
total hip arthroplasty (THA). With freehand positioning of the acetabular
component there is a lack of accuracy, with a trend towards a high
radiographic inclination angle. The aim of this study was to investigate
whether the use of a digital protractor to measure the operative
inclination angle (OI) could improve the positioning of the acetabular
component in relation to a ‘safe zone’. We measured the radiographic inclination angles of 200 consecutive
uncemented primary THAs. In the first 100 the component was introduced
freehand and in the second 100 a digital protractor was used to
measure the operative inclination angle. The mean difference between the operative and the radiographic
inclination angles
(∆RI–OI) in the second cohort was 12.3° (3.8° to 19.8°). There was
a strong correlation between the circumference of the hip and ∆RI–OI.
The number of RI outliers was significantly reduced in the protractor
group (p = 0.002). Adjusting the OI, using a digital protractor and taking into
account the circumference of the patient’s hip, improves the RI
significantly (p <
0.001) and does not require additional operating
time. Cite this article:
Patient specific cutting guides generated by
preoperative Magnetic Resonance Imaging (MRI) of the patient’s extremity
have been proposed as a method of improving the consistency of Total
Knee Arthroplasty (TKA) alignment and adding efficiency to the operative
procedure. The cost of this option was evaluated by quantifying the
savings from decreased operative time and instrument processing
costs compared to the additional cost of the MRI and the guide.
Coronal plane alignment was measured in an unselected consecutive
series of 200 TKAs, 100 with standard instrumentation and 100 with
custom cutting guides. While the cutting guides had significantly lower
total operative time and instrument processing time, the estimated
$322 savings was overwhelmed by the $1,500 additional cost of the
MRI and the cutting guide. All measures of coronal plane alignment
were equivalent between the two groups. The data does not currently
support the proposition that patient specific guides add value to
TKA.
One goal of total hip arthroplasty is to restore normal hip anatomy.
The aim of this study was to compare displacement of the centre
of rotation (COR) using a standard reaming technique with a technique
in which the acetabulum was reamed immediately peripherally and
referenced off the rim. In the first cohort the acetabulum was reamed to the floor followed
by sequentially larger reamers. In the second cohort the acetabulum
was only reamed peripherally, starting with a reamer the same size
as the native femoral head. Anteroposterior pelvic radiographs were
analysed for acetabular floor depth and vertical and horizontal position
of the COR.Aims
Patients and Methods
This prospective randomised controlled trial was designed to
evaluate the outcome of both the MRI- and CT-based patient-specific
matched guides (PSG) from the same manufacturer. A total of 137 knees in 137 patients (50 men, 87 women) were
included, 67 in the MRI- and 70 in the CT-based PSG group. Their
mean age was 68.4 years (47.0 to 88.9). Outcome was expressed as
the biomechanical limb alignment (centre hip-knee-ankle: HKA-axis)
achieved post-operatively, the position of the individual components
within 3° of the pre-operatively planned alignment, correct planned
implant size and operative data (e.g. operating time and blood loss).Aims
Patients and Methods
This study used CT analysis to determine the rotational alignment of 39 painful and 26 painless fixed-bearing total knee replacements (TKRs) from a cohort of 740 NexGen Legacy posterior-stabilised and cruciate-retaining prostheses implanted between May 1996 and August 2003. The mean rotation of the tibial component was 4.3° of internal rotation (25.4° internal to 13.9° external rotation) in the painful group and 2.2° of external rotation (8.5° internal to 18.2° external rotation) in the painfree group (p = 0.024). In the painful group 17 tibial components were internally rotated more than 9° compared with none in the painfree group (p <
0.001). Additionally, six femoral components in the painful group were internally rotated more than 6° compared with none in the painfree group (p = 0.017). External rotational errors were not found to be associated with pain. Overall, 22 (56.4%) of the painful TKRs had internal rotational errors involving the femoral, the tibial or both components. It is estimated that at least 4.6% of all our TKRs have been implanted with significant internal rotational errors.
A retrospective study was conducted to investigate
the changes in metal ion levels in a consecutive series of Birmingham
Hip Resurfacings (BHRs) at a minimum ten-year follow-up. We reviewed
250 BHRs implanted in 232 patients between 1998 and 2001. Implant
survival, clinical outcome (Harris hip score), radiographs and serum chromium
(Cr) and cobalt (Co) ion levels were assessed. Of 232 patients, 18 were dead (five bilateral BHRs), 15 lost
to follow-up and ten had been revised. The remaining 202 BHRs in
190 patients (136 men and 54 women; mean age at surgery 50.5 years
(17 to 76)) were evaluated at a minimum follow-up of ten years (mean
10.8 years (10 to 13.6)). The overall implant survival at 13.2 years
was 92.4% (95% confidence interval 90.8 to 94.0). The mean Harris
hip score was 97.7 (median 100; 65 to 100). Median and mean ion
levels were low for unilateral resurfacings (Cr: median 1.3 µg/l,
mean
1.95 µg/l (<
0.5 to 16.2); Co: median 1.0 µg/l, mean 1.62 µg/l
(<
0.5 to 17.3)) and bilateral resurfacings (Cr: median 3.2 µg/l,
mean 3.46 µg/l (<
0.5 to 10.0); Co: median 2.3 µg/l, mean 2.66
µg/l (<
0.5 to 9.5)). In 80 unilateral BHRs with sequential ion
measurements, Cr and Co levels were found to decrease significantly
(p <
0.001) from the initial assessment at a median of six years
(4 to 8) to the last assessment at a median of 11 years (9 to 13),
with a mean reduction of 1.24 µg/l for Cr and 0.88 µg/l for Co.
Three female patients had a >
2.5 µg/l increase of Co ions, associated with
head sizes ≤ 50 mm, clinical symptoms and osteolysis. Overall, there
was no significant difference in change of ion levels between genders
(Cr, p = 0.845; Co, p = 0.310) or component sizes (Cr, p = 0.505;
Co, p = 0.370). Higher acetabular component inclination angles correlated
with greater change in ion levels (Cr, p = 0.013; Co, p = 0.002).
Patients with increased ion levels had lower Harris hip scores (p
= 0.038). In conclusion, in well-functioning BHRs the metal ion levels
decreased significantly at ten years. An increase >
2.5 µg/l was
associated with poor function. Cite this article: