We report ten-year clinical and radiological
follow-up data for the Sigma Press Fit Condylar total knee replacement system
(Sigma PFC TKR). Between October 1998 and October 1999 a total of
235 consecutive PFC Sigma TKRs were carried out in 203 patients.
Patients were seen at a specialist nurse-led clinic seven to ten
days before admission and at six and 18 months, three, five and
eight to ten years after surgery. Data were recorded prospectively
at each clinic visit. Radiographs were obtained at the five- and
eight- to ten-year follow-up appointments. Of the 203 patients,
147 (171 knees) were alive at ten years and 12 were lost to follow-up.
A total of eight knees (3.4%) were revised, five for infection and
three to change the polyethylene insert. The survival at ten years
with an endpoint of revision for any reason was 95.9%, and with
an endpoint of revision for aseptic failure was 98.7%. The mean
American Knee Society Score (AKSS) was 79 (10 to 99) at eight to
ten years, compared with 31 (2 to 62) pre-operatively. Of 109 knee
with radiographs reviewed, 47 knees had radiolucent lines but none
showed evidence of loosening. Cite this article:
Gender-specific total knee replacement has generated much interest recently. We reviewed 1970 Sigma knees implanted in 920 women and 592 men with a mean age of 69.7 years. At a mean follow-up of 7.3 years (minimum, five years), we found minimal differences in the outcome between genders. At the final follow-up, men had a higher overall Knee Society score and more osteolysis (3.8% vs 1.1%). However, there were no significant differences between men and women in terms of complications or improvements in knee function, pain score or range of movement. The estimated ten-year survivorship was 97% in women and 98% in men (p = 0.96). We concluded that there was little difference in outcome between the genders treated by a modern unisex design of total knee replacement in this large multicentre study.
Locking after total knee replacement is uncommon and is generally caused by the formation of fibrous tissue around the patella. We report an unusual cause of locking resulting from intermittent occlusion of the popliteal artery, which was tethered to cement at the posterior aspect of the tibial component.
We describe the mid-term results of a prospective study of total knee replacement in severe valgus knees using an osteotomy of the lateral femoral condyle and computer navigation. There were 15 knees with a mean valgus deformity of 21° (17° to 27°) and a mean follow-up of 28 months (24 to 60). A cemented, non-constrained fixed bearing, posterior-cruciate-retaining knee prosthesis of the same design was used in all cases (Columbus-B. Braun; Aesculap, Tuttlingen, Germany). All the knees were corrected to a mean of 0.5° of valgus (0° to 2°). Flexion of the knee had been limited to a mean of 85° (75° to 110°) pre-operatively and improved to a mean of 105° (90° to 130°) after operation. The mean Knee Society score improved from 37 (30 to 44) to 90 points (86 to 94). Osteotomy of the lateral femoral condyle combined with computer-assisted surgery gave an excellent mid-term outcome in patients undergoing total knee replacement in the presence of severe valgus deformity.
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 results of hip and knee replacement surgery
are generally regarded as positive for patients. Nonetheless, they are
both major operations and have recognised complications. We present
a review of relevant claims made to the National Health Service
Litigation Authority. Between 1995 and 2010 there were 1004 claims
to a value of £41.5 million following hip replacement surgery and
523 claims to a value of £21 million for knee replacement. The most common
complaint after hip surgery was related to residual neurological
deficit, whereas after knee replacement it was related to infection.
Vascular complications resulted in the highest costs per case in
each group. Although there has been a large increase in the number of operations
performed, there has not been a corresponding relative increase
in litigation. The reasons for litigation have remained largely
unchanged over time after hip replacement. In the case of knee replacement,
although there has been a reduction in claims for infection, there
has been an increase in claims for technical errors. There has also
been a rise in claims for non-specified dissatisfaction. This information
is of value to surgeons and can be used to minimise the potential
mismatch between patient expectation, informed consent and outcome. Cite this article:
The Cementless Oxford Unicompartmental Knee Replacement
(OUKR) was developed to address problems related to cementation,
and has been demonstrated in a randomised study to have similar
clinical outcomes with fewer radiolucencies than observed with the
cemented device. However, before its widespread use it is necessary
to clarify contraindications and assess the complications. This
requires a larger study than any previously published. We present a prospective multicentre series of 1000 cementless
OUKRs in 881 patients at a minimum follow-up of one year. All patients
had radiological assessment aligned to the bone–implant interfaces
and clinical scores. Analysis was performed at a mean of 38.2 months
(19 to 88) following surgery. A total of 17 patients died (comprising
19 knees (1.9%)), none as a result of surgery; there were no tibial
or femoral loosenings. A total of 19 knees (1.9%) had significant
implant-related complications or required revision. Implant survival
at six years was 97.2%, and there was a partial radiolucency at
the bone–implant interface in 72 knees (8.9%), with no complete radiolucencies.
There was no significant increase in complication rate compared
with cemented fixation (p = 0.87), and no specific contraindications
to cementless fixation were identified. Cementless OUKR appears to be safe and reproducible in patients
with end-stage anteromedial osteoarthritis of the knee, with radiological
evidence of improved fixation compared with previous reports using
cemented fixation. Cite this article:
The June 2012 Children’s orthopaedics Roundup360 looks at; open reduction for DDH; growing rod instrumentation for scoliosis; acute patellar dislocation; management of the relapsed clubfoot; clubfoot in Iran; laughing gas and fracture manipulation; vascularised periosteal fibular grafting for nonunion; slipped upper femoral epiphysis; intramedullary leg lengthening and orthopaedic imaging and defensive medicine.
We have investigated the errors in the identification of the transepicondylar axis and the anteroposterior axis between a minimally-invasive and a conventional approach in four fresh-frozen cadaver knees. The errors in aligning the femoral prosthesis were compared with the reference transepicondylar axis as established by CT. The error in the identification of the transepicondylar axis was significantly higher in the minimal approach (4.5° of internal rotation,
In a global environment of rising costs and limited funds, robotic and computer-assisted orthopaedic technologies could provide the means to drive a necessary revolution in arthroplasty productivity. Robots have been used to operate on humans for 20 years, but the adoption of the technology has lagged behind that of the manufacturing industry. The use of robots in surgery should enable cost savings by reducing instrumentation and inventories, and improving accuracy. Despite these benefits, the orthopaedic community has been resistant to change. If the ergonomics and economics are right, robotic technology just might transform the provision of joint replacement.
Pain is the main indication for performing total knee replacement (TKR). In most patients after TKR there is an improvement, but a few continue to have pain. Generally, the cause of the pain can be addressed when it is identified. However, unexplained pain can be more difficult to manage because revision surgery is likely to be unrewarding in this group. In our study of 622 cemented TKRs in 512 patients with a mean age of 69 years (23 to 90) treated between January 1995 and August 1998, we identified 24 patients (knees) with unexplained pain at six months. This group was followed for five years (data was unavailable for 18 knees) and ten patients (55.5%) went on to show an improvement without intervention. In the case of unexplained pain, management decisions must be carefully considered, but reassurance can be offered to patients that the pain will improve in more than half with time.
We describe our experience with the ‘four-in-one’ procedure for habitual dislocation of the patella in five children (six knees). All the patients presented with severe generalised ligamentous laxity and aplasia of the trochlear groove. All had a lateral release, proximal ‘tube’ realignment of the patella, semitendinosus tenodesis and transfer of the patellar tendon. The mean age at the time of the operation was 6.1 years (4.9 to 6.9), and the patients were followed up for a mean of 54.5 months (31 to 66). The clinical results were evaluated using the Kujala score. There has been no recurrence of dislocation. All the patients have returned to full activities and the parents and children were satisfied with the clinical results. The mean Kujala score was 95.3 (88 to 98). Two patients had marginal skin necrosis which healed after debridement and secondary closure. These early results in this small group have shown that the ‘four-in-one’ procedure is effective in the treatment of obligatory dislocation of the patella in children with severe ligamentous laxity and trochlear aplasia.
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.
Matrix-assisted autologous chondrocyte transplantation (MACT)
has been developed and applied in the clinical practice in the last
decade to overcome most of the disadvantages of the first generation
procedures. The purpose of this systematic review is to document
and analyse the available literature on the results of MACT in the
treatment of chondral and osteochondral lesions of the knee. All studies published in English addressing MACT procedures were
identified, including those that fulfilled the following criteria:
1) level I-IV evidence, 2) measures of functional or clinical outcome,
3) outcome related to cartilage lesions of the knee cartilage.Objectives
Methods
The outcome of arthroscopic medial release of 255 knees in 173 patients for varying grades of osteoarthritis involving the medial compartment is reported. All operations were performed by a single surgeon between January 2001 and May 2003. The Knee Society score for pain and the patient’s subjective satisfaction were used for the outcome evaluation. Overall, satisfactory outcome was reported for 197 knees (77.3%) and the mean Knee Society score for pain improved from 17.6 (95% confidence interval, 16.7 to 18.5), pre-operatively to 39.4 (95% confidence interval, 37.9 to 41.1) (p <
0.001). There were minor manageable complications of persistent effusion in 16 knees and prolonged wound discomfort in 11. In total, 15 of the 21 knees with poor results were converted to total knee replacements and two other patients (three knees) were offered this option after a mean period of 16 months. Based on these observations arthroscopic medial release is an effective treatment for osteoarthritis of the medial compartment of the knee joint and can be expected to reduce the pain in the majority of patients for at least four years post-operatively.
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.
Radiological assessment of total and unicompartmental
knee replacement remains an essential part of routine care and follow-up.
Appreciation of the various measurements that can be identified
radiologically is important. It is likely that routine plain radiographs
will continue to be used, although there has been a trend towards
using newer technologies such as CT, especially in a failing knee,
where it provides more detailed information, albeit with a higher
radiation exposure. The purpose of this paper is to outline the radiological parameters
used to evaluate knee replacements, describe how these are measured
or classified, and review the current literature to determine their
efficacy where possible.
There remains a lack of data on the reliability of methods to
estimate tibial coverage achieved during total knee replacement.
In order to address this gap, the intra- and interobserver reliability
of a three-dimensional (3D) digital templating method was assessed
with one symmetric and one asymmetric prosthesis design. A total of 120 template procedures were performed according to
specific rotational and over-hang criteria by three observers at
time zero and again two weeks later. Total and sub-region coverage
were calculated and the reliability of the templating and measurement
method was evaluated.Objectives
Methods
We examined the placement of the stem in relation to the medial tibial cortex when using total knee replacements (TKRs) with medially-offset tibial stems in Korean patients. Measurements were performed on the pre- and post-operative radiographs of 246 osteoarthritic knees replaced between January 2005 and May 2006 using the Genesis II or E-motion TKR with a medially-offset stem. Pre-operatively, we measured the distance between the mechanical axis and that of the tibial shaft and post-operatively, that between the midline of the tibial stem and the axis of the shaft. Knees were identified in which there was radiological contact between the tip of the stem and the medial tibial cortex. The mechanical axis was located medial to the axis of the shaft in 203 knees (82.5%). Post-operatively, the midline of the tibial stem was located medial to the tibial shaft axis in 196 knees (79.7%). In 16 knees (6.5%) there was radiological contact between the tibial stem or cement mantle and the medial tibial cortex. Our study has shown that the medially-offset stem in the tibial component may not be a good option for knees undergoing replacement for advanced osteoarthritis in some Korean patients.