The diagnosis of periprosthetic joint infection (PJI) continues to present a significant clinical challenge. New biomarkers have been proposed to support clinical decision-making; among them, synovial fluid alpha-defensin has gained interest. Current research methodology suggests reference methods are needed to establish solid evidence for use of the test. This prospective study aims to evaluate the diagnostic accuracy of high-performance liquid chromatography coupled with the mass spectrometry (LC-MS) method to detect alpha-defensin in synovial fluid. Between October 2017 and September 2019, we collected synovial fluid samples from patients scheduled to undergo revision surgery for painful total knee arthroplasty (TKA). The International Consensus Meeting criteria were used to classify 33 PJIs and 92 aseptic joints. LC-MS assay was performed to measure alpha-defensin in synovial fluid of all included patients. Sensitivity, specificity, positive predictive value, negative predictive value, and the area under the receiver operating characteristic curve (AUC) were calculated to define the test diagnostic accuracy.Aims
Methods
Our aim was to examine the clinical and radiographic outcomes
in 257 consecutive Oxford unicompartmental knee arthroplasties (OUKAs)
(238 patients), five years post-operatively. A retrospective evaluation was undertaken of patients treated
between April 2008 and October 2010 in a regional centre by two
non-designing surgeons with no previous experience of UKAs. The
Oxford Knee Scores (OKSs) were recorded and fluoroscopically aligned
radiographs were assessed post-operatively at one and five years.Aims
Patients and Methods
This randomised trial evaluated the outcome of
a single design of unicompartmental arthroplasty of the knee (UKA) with
either a cemented all-polyethylene or a metal-backed modular tibial
component. A total of 63 knees in 45 patients (17 male, 28 female)
were included, 27 in the all-polyethylene group and 36 in the metal-backed
group. The mean age was 57.9 years (39.6 to 76.9). At a mean follow-up
of 6.4 years (5 to 9.9), 11 all-polyethylene components (41%) were
revised (at a mean of 5.8 years; 1.4 to 8.0) post-operatively and
two metal-backed components were revised (at one and five years).
One revision in both groups was for unexplained pain, one in the
metal-backed group was for progression of osteoarthritis. The others
in the all-polyethylene group were for aseptic loosening. The survivorship
at seven years calculated by the Kaplan–Meier method for the all-polyethylene
group was 56.5% (95% CI 31.9 to 75.2, number at risk 7) and for
the metal-backed group was 93.8% (95% CI 77.3 to 98.4, number at
risk 16) This difference was statistically significant (p <
0.001).
At the most recent follow-up, significantly better mean Western
Ontario and McMaster Universities Arthritis Index Scores were found
in the all-polyethylene group (13.4 This randomised study demonstrates that all-polyethylene components
in this design of fixed bearing UKA had unsatisfactory results with
significantly higher rates of failure before ten years compared
with the metal-back components. Cite this article:
Matrix-induced autologous chondrocyte implantation
(MACI) is an established technique used to treat osteochondral lesions
in the knee. For larger osteochondral lesions (>
5 cm2)
deeper than approximately 8 mm we have combined the use of two MACI
membranes with impaction grafting of the subchondral bone. We report
our results of 14 patients who underwent the ‘bilayer collagen membrane’
technique (BCMT) with a mean follow-up of 5.2 years (2 to 8). There
were 12 men and two women with a mean age of 23.6 years (16 to 40).
The mean size of the defect was 7.2 cm2 (5.2 to 12 cm2)
and were located on the medial (ten) or lateral (four) femoral condyles.
The mean modified Cincinnati knee score improved from 45.1 (22 to
70) pre-operatively to 82.8 (34 to 98) at the most recent review
(p <
0.05). The visual analogue pain score improved from 7.3
(4 to 10) to 1.7 (0 to 6) (p <
0.05). Twelve patients were considered
to have a good or excellent clinical outcome. One graft failed at
six years. The BCMT resulted in excellent functional results and durable
repair of large and deep osteochondral lesions without a high incidence
of graft-related complications.
We attempted to characterise the biological quality
and regenerative potential of chondrocytes in osteochondritis dissecans
(OCD). Dissected fragments from ten patients with OCD of the knee
(mean age 27.8 years (16 to 49)) were harvested at arthroscopy.
A sample of cartilage from the intercondylar notch was taken from
the same joint and from the notch of ten patients with a traumatic
cartilage defect (mean age 31.6 years (19 to 52)). Chondrocytes
were extracted and subsequently cultured. Collagen types 1, 2, and
10 mRNA were quantified by polymerase chain reaction. Compared with
the notch chondrocytes, cells from the dissecate expressed similar
levels of collagen types 1 and 2 mRNA. The level of collagen type
10 message was 50 times lower after cell culture, indicating a loss
of hypertrophic cells or genes. The high viability, retained capacity
to differentiate and metabolic activity of the extracted cells suggests
preservation of the intrinsic repair capability of these dissecates.
Molecular analysis indicated a phenotypic modulation of the expanded
dissecate chondrocytes towards a normal phenotype. Our findings
suggest that cartilage taken from the dissecate can be reasonably
used as a cell source for chondrocyte implantation procedures.
Autologous chondrocyte implantation is an option in the treatment of full-thickness chondral or osteochondral injuries which are symptomatic. The goal of surgery and rehabilitation is the replacement of damaged cartilage with hyaline or hyaline-like cartilage, producing improved levels of function and preventing early osteoarthritis. The intermediate results have been promising in terms of functional and clinical improvement. Our aim was to explore the hypothesis that the histological quality of the repair tissue formed after autologous chondrocyte implantation improved with increasing time after implantation. In all, 248 patients who had undergone autologous chondrocyte implantation had biopsies taken of the repair tissue which then underwent histological grading. Statistical analysis suggested that with doubling of the time after implantation the likelihood of a favourable histological outcome was increased by more than fourfold (p <
0.001).
We report a consecutive series of 16 revision total knee arthroplasties using the Total Condylar III system in 14 patients with inflammatory arthritis which were performed between 1994 and 2000. There were 11 women and three men with a mean age of 59 years (36 to 78). The patients were followed up for 74 months (44 to 122). The mean pre-operative Knee Society score of 37 points (0 to 77) improved to 88 (61 to 100) at follow-up ( These results suggest that the Total Condylar III system can be used successfully in revision total knee arthroplasty in inflammatory arthritis.
We investigated the prognostic indicators for collagen-covered autologous chondrocyte implantation (ACI-C) performed for symptomatic osteochondral defects of the knee. We analysed prospectively 199 patients for up to four years after surgery using the modified Cincinnati score. Arthroscopic assessment and biopsy of the neocartilage was also performed whenever possible. The favourable factors for ACI-C include younger patients with higher pre-operative modified Cincinnati scores, a less than two-year history of symptoms, a single defect, a defect on the trochlea or lateral femoral condyle and patients with fewer than two previous procedures on the index knee. Revision ACI-C in patients with previous ACI and mosaicplasties which had failed produced significantly inferior clinical results. Gender (p = 0.20) and the size of the defect (p = 0.97) did not significantly influence the outcome.
Autologous chondrocyte implantation (ACI) is used widely as a treatment for symptomatic chondral and osteochondral defects of the knee. Variations of the original periosteum-cover technique include the use of porcine-derived type I/type III collagen as a cover (ACI-C) and matrix-induced autologous chondrocyte implantation (MACI) using a collagen bilayer seeded with chondrocytes. We have performed a prospective, randomised comparison of ACI-C and MACI for the treatment of symptomatic chondral defects of the knee in 91 patients, of whom 44 received ACI-C and 47 MACI grafts. Both treatments resulted in improvement of the clinical score after one year. The mean modified Cincinnati knee score increased by 17.6 in the ACI-C group and 19.6 in the MACI group (p = 0.32). Arthroscopic assessments performed after one year showed a good to excellent International Cartilage Repair Society score in 79.2% of ACI-C and 66.6% of MACI grafts. Hyaline-like cartilage or hyaline-like cartilage with fibrocartilage was found in the biopsies of 43.9% of the ACI-C and 36.4% of the MACI grafts after one year. The rate of hypertrophy of the graft was 9% (4 of 44) in the ACI-C group and 6% (3 of 47) in the MACI group. The frequency of re-operation was 9% in each group. We conclude that the clinical, arthroscopic and histological outcomes are comparable for both ACI-C and MACI. While MACI is technically attractive, further long-term studies are required before the technique is widely adopted.