Total hip arthroplasty in patients with chronic liver disease: A systematic review

INTRODUCTION

Chronic liver disease (CLD) is a significant and increasingly prevalent co-morbidity in patients undergoing total hip arthroplasty (THA). These patients may develop metabolic bone disease (MBD) and systemic dysfunction, which pose challenges to THA surgery. This systematic review of literature aims to examine clinical outcomes and complications in patients with CLD undergoing THA and provide evidence-based approaches as to the optimization of their perioperative care.

METHODS

A Pubmed search was performed, identifying eight studies on 28 514 THAs for inclusion. Two additional studies reported on 44 patients undergoing THA post liver transplant. These were reviewed separately.

RESULTS

Increased early perioperative complications are reported recurrently. Review of long-term complications demonstrates an increased postoperative infection rate of 0.5% (p < 0.001) and perioperative mortality of 4.1% (p < 0.001). The need for revision surgery is more frequent at 4% (p < 0.001). Aetiology of need for revision surgery included; periprosthestic infection (70%), aseptic loosening (13%), instability (13%), periprosthetic fracture (2%) and liner wear (2%). THA in patients with liver transplants seems to offer functional improvement; however, no studies have formally assessed functional outcomes in the patient with active CLD.

DISCUSSION

A multidisciplinary perioperative approach is suggested in order to minimize increased complication risks. Specific measures include optimizing haemoglobin and taking measures to reduce infection. This review also highlights gaps in available literature and guides future research to appraise functional outcomes, further detail long-term failure reasons and study any differences in outcomes and complications based on the range of operative approaches and available implant choices.

Systematic review of the outcome of cemented versus uncemented total hip arthroplasty following pelvic irradiation

PURPOSE

The objective of this study is to evaluate the outcomes of total hip arthroplasty (THA) in patients with radiation-related changes to the bone, and specifically whether there is a difference in outcomes between cemented and uncemented acetabular components.

METHODS

A database search was performed to identify available studies reporting adults undergoing THA who have previously had pelvic irradiation. Data were extracted and analysed with respect to the use of cemented versus uncemented acetabular components. Statistical analysis was performed using the Chi-square test for independence.

RESULTS

The all-cause revision rate was 24% in the cemented THA group (27/111), compared with 15% of uncemented THAs (22/143) (p = 0.073). Revision for acetabular aseptic loosening occurred in 16% of cases (18/111) in the cemented group and 10% (15/143) in the uncemented group (p = 0.178). Acetabular aseptic loosening was reported in 24% of cemented THAs (27/111) and 14% of uncemented THAs (20/143), which was statistically significant (p = 0.035). Not all of these went on to have revision THA. The Incidence of prosthetic joint infection was similar in both groups.

CONCLUSION

Overall outcomes appear to be better for uncemented THAs in post-radiotherapy patients, with a significantly lower rate of aseptic loosening and an appreciable (but not statistically significant) reduction in revision rate. The best outcomes seem to be associated with the use of acetabular reinforcement across both cemented and uncemented groups, but further work is needed to evaluate this.

The outcomes of total knee arthroplasty in morbidly obese patients: a systematic review of the literature

INTRODUCTION

The increasing prevalence of obesity has led to an increase in total knee arthroplasties (TKAs) being undertaken in patients with a higher body mass index (BMI). TKA in morbidly obese patients can be technically challenging due to numerous anatomical factors and patient co-morbidities. The long-term outcomes in this patient group are unclear. This systematic review aims to compare the long-term revision rates, functional outcomes and complication rates of TKAs in morbidly obese versus non-obese patients.

METHODS

A search of PubMed, EMBASE and PubMed Central was conducted to identify studies that reported revision rates in a cohort of morbidly obese patients (BMI ≥ 40 kg/m²) that underwent primary TKA, compared to non-obese patients (BMI ≤ 30 kg/m²). Secondary outcomes included Knee Society Objective Scores (KSOS), Knee Society Functional Scores (KSFS), and complication rates between the two groups. The difference in revision rates was assessed using the Chi-squared test. The Wilcoxon signed-rank test was used to compare pre-operative and post-operative functional scores for each group. KSOS and KSFS for morbidly obese and non-obese patients were compared using the Mann-Whitney test. Statistical significance was defined as p ≤ 0.05.

RESULTS

Nine studies were included in this review. There were 624 TKAs in morbidly obese patients and 9,449 TKAs in non-obese patients, average BMI values were 45.0 kg/m² (range 40-66 kg/m²) and 26.5 kg/m² (range 11-30 kg/m²) respectively. The average follow-up time was 4.8 years (range 0.5-14.1) and 5.2 years (range 0.5-13.2) respectively, with a revision rate of 7% and 2% (p < 0.001) respectively. All functional scores improved after TKA (p < 0.001). Pre- and post-operative KSOS and KSFS were poorer in morbidly obese patients, however, mean improvement in KSOS was the same in both groups and comparable between groups for KSFS (p = 0.78). Overall complication rates,  including infection, were higher in morbidly obese patients.

CONCLUSIONS

This review suggests an increased mid to long-term revision rate following primary TKA in morbidly obese patients, however, these patients have a functional recovery which is comparable to non-obese individuals. There is also an increased risk of perioperative complications, such as superficial wound infection. Morbidly obese patients should be fully informed of these issues prior to undergoing primary TKA.

Total knee arthroplasty in patients with Paget’s disease of bone: A systematic review

AIM

To determine the functional outcomes, complications and revision rates following total knee arthroplasty (TKA) in patients with Paget’s disease of bone (PDB).

METHODS

A systematic review of the literature was performed. Four studies with a total of 54 TKAs were included for analysis. Functional outcomes, pain scores, complications and revision rates were assessed. The mean age was 72.0 years and the mean follow-up was 7.5 years.

RESULTS

All studies reported significant improvement in knee function and pain scores following TKA. There were 2 cases of aseptic loosening, with one patient requiring revision of the femoral component 10 years after the index procedure. Malalignment, bone loss, soft tissue contractures were the most commonly reported intra-operative challenges. There were five cases (9%) that were complicated by intra-operative patellar tendon avulsion.

CONCLUSION

The findings support the use of TKA in patients with PDB. The post-operative functional outcomes are largely similar to other patients, however there are specific perioperative challenges that have been highlighted, in particular the high risk for patellar tendon avulsion.

Total hip arthroplasty outcomes in morbidly obese patients: A systematic review

The increasing prevalence of obesity has resulted in a marked increase in the number of total hip arthroplasties (THAs) carried out in patients with a high body mass index (BMI).

THA in morbidly obese patients is often technically challenging owing to the associated co-morbidities and anatomical factors. Furthermore, the long-term clinical and functional outcomes of the procedure in these patients are not clear.

The aim of this systematic review was to compare the long-term failure rate and functional outcomes of THA in morbidly obese versus non-obese patients.

A literature search of PubMed, EMBASE and PubMed Central was conducted to identify studies that compared the outcomes of THA in patients defined as morbidly obese (BMI ≥ 35) to a control group (BMI < 30). The primary and secondary outcome measures were rate of revision and functional outcome, respectively, in the long term.

Eight studies were included in this review. There were 66,238 THAs in morbidly obese patients and 705,619 THAs in patients with a BMI < 30. The overall revision rate was 7.99% in the morbidly obese patients versus 2.75% in the non-obese controls. The functional outcome was at least comparable to non-obese patients.

This review suggests that morbidly obese patients have a slightly increased revision rate following THA. Importantly, these patients have a functional recovery at least comparable to those with a BMI < 30. Morbidly obese patients should be fully informed of these issues prior to undergoing surgery.

Cite this article: EFORT Open Rev 2018;3:507-512. DOI: 10.1302/2058-5241.3.180011

Outcome of total knee arthroplasty in patients with poliomyelitis: A systematic review

Total knee arthroplasty (TKA) in patients affected by poliomyelitis is technically challenging owing to abnormal anatomical features including articular and metaphyseal angular deformities, external rotation of the tibia, excessive valgus alignment, bone loss, narrowness of the femoral and tibial canals, impaired quadriceps strength, flexion contractures, genu recurvatum and ligamentous laxity. Little information is available regarding the results and complications of TKA in this challenging group of patients.

We carried out a systematic review of the literature to determine the functional outcome, complications and revision rates of TKA in patients with poliomyelitis-affected knees. Six studies including 82 knees met the inclusion criteria and were reviewed. The mean patient age was 63 years (45 to 85) and follow-up was 5.5 years (0.5 to 13).

All studies reported significant improvement in knee function following TKA. There were six failures requiring revision surgery in 82 cases (7%) occurring at a mean of 6.2 years (0.4 to 12). The reasons for revision surgery were aseptic loosening (17%, n=1), infection (33%, n=2), periprosthetic fracture (17%, n=1) and instability (33%, n=2). Thirty-six knees had a degree of recurvatum pre-operatively (44%), which was in the range of 5° to 30°. Ten of these knees (28%) developed recurrent recurvatum post-operatively.

The findings support the use of TKA in patients with poliomyelitis-affected knees. The post-operative functional outcome is similar to other patients; however, the revision rate is higher. Quadriceps muscle power appears to be an important prognostic factor for functional outcome and the use of constrained implant designs is recommended in the presence of less than antigravity quadriceps strength.

Cite this article: EFORT Open Rev 2018;3:358-362. DOI: 10.1302/2058-5241.3.170028

Clinical, functional and radiological outcomes of extracorporeal irradiation in limb salvage surgery for bone tumours

AIMS

We present a retrospective review of patients treated with extracorporeally irradiated allografts for primary and secondary bone tumours with the mid- and long-term survivorship and the functional and radiographic outcomes.

PATIENTS AND METHODS

A total of 113 of 116 (97.4%) patients who were treated with extracorporeally irradiated allografts between 1996 and 2014 were followed up. Forms of treatment included reconstructions, prostheses and composite reconstructions, both with and without vascularised grafts. Survivorship was determined by the Kaplan-Meier method. Clinical outcomes were assessed using the Musculoskeletal Tumor Society (MSTS) scoring system, the Toronto Extremity Salvage Score (TESS) and Quality of Life-C30 (QLQ-30) measures. Radiographic outcomes were assessed using the International Society of Limb Salvage (ISOLS) radiographic scoring system.

RESULTS

There were 61 (54%) men with a mean age of 22 years (6 to 70) and 52 (46%) women with a mean age of 26 years (3 to 85). There were 23 deaths. The five-year patient survivorship was 82.3% and the ten-year patient survivorship was 79.6%. The mean follow-up of the 90 surviving patients was 80.3 months (2 to 207). At the last follow-up, 105 allografts (92.9%) were still in place or had been at the time of death; eight (7%) had failed due to infection, local recurrence or fracture. Outcome scores were comparable with or superior to those in previous studies. The mean outcome scores were: MSTS 79% (sd 8); TESS 83% (sd 19); QLQ 82% (sd 16); ISOLS 80.5% (sd 19). Pearson correlation analysis showed a strong relationship between the MSTS and ISOLS scores (r = 0.71, p < 0.001).

CONCLUSION

This study shows that extracorporeal irradiation is a versatile reconstructive technique for dealing with large defects after the resection of bone tumours with good functional and radiographic outcomes. Functional outcomes as measured by MSTS, TESS and QLQ-30 were strongly correlated to radiographic outcomes. Cite this article: Bone Joint J 2017;99-B:1681-8.

Total hip arthroplasty in patients with Paget’s disease of bone: A systematic review

AIM

To investigate the clinical and functional outcomes following total hip arthroplasty (THA) in patients with Paget’s disease.

METHODS

We carried out a systematic review of the literature to determine the functional outcome, complications and revision rates of THA in patients with Paget’s disease. Eight studies involving 358 hips were reviewed. The mean age was 70.4 years and follow-up was 8.3 years. There were 247 cemented THAs (69%), 105 uncemented THAs (29%) and 6 hybrid THAs (2%).

RESULTS

All studies reported significant improvement in hip function following THA. There were 19 cases of aseptic loosening (5%) at a mean of 8.6 years. Three cases occurred in the uncemented cohort (3%) at a mean of 15.3 years and 16 cases developed in the cemented group (6%) at a mean of 7.5 years (P = 0.2052). There were 27 revisions in the 358 cases (8%) occurring at a mean of 7 years. Six revisions occurred in the uncemented cohort (6%) at a mean of 8.6 years and 21 in the cemented cohort (9%) at a mean of 6.5 years (P = 0.5117).

CONCLUSION

The findings support the use of THA in patients with Paget’s disease hip arthropathy. The post-operative functional outcome is largely similar to other patients; however, the revision rate is higher with aseptic loosening being the most common reason for revision. Uncemented implants appear to be associated with a lower failure rate, however, there were no modern stem designs fixed using current generation cementing techniques used in the reported studies, and as such, caution is advised when drawing any conclusions.

A loop-mediated isothermal amplification method for rapid direct detection and differentiation of nonpathogenic and verocytotoxigenic Escherichia coli in beef and bovine faeces

AIM

To develop a multiplex loop-mediated isothermal amplification (LAMP) assay capable of quantifying Escherichia coli and differentiating verocytotoxigenic E. coli (VTEC).

METHODS AND RESULTS

Primer sets were selected to amplify the phoA gene (all E. coli strains) and stx1 and/or stx2 genes (VTEC strains only). LAMP calibration curves demonstrated good quantification capability compared with conventional culture. The limits of detection 50% (LOD₅₀ ) of the multiplex LAMP assay were 2·8 (95% CI 2·4-3·3), 3·2 (95% CI 2·5-3·9) and 2·8-3·2 (95% CI 2·1-3·5) log CFU per g for the phoA, stx1 and stx2 genes, respectively. When validated by testing retail beef and bovine faeces samples, good correlation between E. coli counts indicated by the LAMP assay and culture was observed; however, false-negative LAMP assay results were obtained for 12·5-14·7% of samples.

CONCLUSIONS

A rapid, multiplex LAMP assay for direct quantification of E. coli and specific detection of VTEC in beef and faeces was successfully developed. Further optimisation of the assay would be needed to improve detection sensitivity.

SIGNIFICANCE AND IMPACT OF THE STUDY

The multiplex LAMP assay represents a rapid alternative to culture for monitoring E. coli levels on beef for hygiene monitoring purposes, and, potentially, a method for detection of VTEC in beef and faeces.

What is the minimum amount of simulated breast movement required for visual detection of blurring? An exploratory investigation

OBJECTIVE

Image blurring in mammography can cause significant image degradation and interpretational problems. A potential source is due to paddle movement during image formation. Paddle movement has been shown to be as much as 1.5 mm. No study has yet been performed to determine how much motion would be noticeable visually. The aim of this study is to determine the minimum amount of simulated breast movement at which blurring can be detected visually.

METHODS

25 artefact-free mammogram images were selected. Mathematical simulation software was created to mimic the effect of blurring produced by breast movement during exposure. Motion simulation was imposed to 15 levels, from 0.1 to 1.5 mm stepping through 0.1 mm increments. 15 degraded images and 1 without blurring were de-identified, randomized and assessed on a blinded basis by two clinical experts to determine the presence or absence of blurring. Statistical testing was carried out to determine the consistency between the two observers.

RESULTS

The probability of simulated blurred image detection is the highest for the gaussian method and the lowest for soft-edged mask estimation.

CONCLUSION

The amount of simulated breast movement at which blurring can be detected visually for gaussian blur, hard-edge mask estimation and soft-edge mask estimation is 0.4, 0.8 and 0.7 mm, respectively. Cohen's kappa for all the levels of simulated blurring is 0.689 (p < 0.05).

ADVANCES IN KNOWLEDGE

This research establishes the concept of using probability to represent visual detection of blurring rather than defining a hard cut-off level.

Extra patient movement during mammographic imaging: an experimental study

OBJECTIVE

To determine if movement external to the patient occurring during mammography may be a source of image blur.

METHODS

Four mammography machines with eight flexible and eight fixed paddles were evaluated. In the first stage, movement at the paddle was measured mechanically using two calibrated linear potentiometers. A deformable breast phantom was used to mimic a female breast. For each paddle, the movement in millimetres and change in compression force in Newton was recorded at 0.5- and 1-s intervals, respectively, for 40 s with the phantom in an initially compressed state under a load of 80 N. In the second stage, clinical audit on 28 females was conducted on one mammography machine with the 18 × 24- and 24 × 29-cm flexible paddles.

RESULTS

Movement at the paddle followed an exponential decay with a settling period of approximately 40 s. The compression force readings for both fixed and flexible paddles decreased exponentially with time, while fixed paddles had a larger drop in compression force than did flexible paddles. There is a linear relationship between movement at the paddle and change in compression force.

CONCLUSION

Movement measured at the paddle during an exposure can be represented by a second order system. The amount of extra patient movement during the actual exposure can be estimated using the linear relationship between movement at the paddle and the change in compression force.

ADVANCES IN KNOWLEDGE

This research provides a possible explanation to mammography image blurring caused by extra patient movement and proposes a theoretical model to analyse the movement.

Rapid estimation of cartilage T2 based on double echo at steady state (DESS) with 3 Tesla

The double-echo-steady-state (DESS) sequence generates two signal echoes that are characterized by a different contrast behavior. Based on these two contrasts, the underlying T2 can be calculated. For a flip-angle of 90 degrees , the calculated T2 becomes independent of T1, but with very low signal-to-noise ratio. In the present study, the estimation of cartilage T2, based on DESS with a reduced flip-angle, was investigated, with the goal of optimizing SNR, and simultaneously minimizing the error in T2. This approach was validated in phantoms and on volunteers. T2 estimations based on DESS at different flip-angles were compared with standard multiecho, spin-echo T2. Furthermore, DESS-T2 estimations were used in a volunteer and in an initial study on patients after cartilage repair of the knee. A flip-angle of 33 degrees was the best compromise for the combination of DESS-T2 mapping and morphological imaging. For this flip angle, the Pearson correlation was 0.993 in the phantom study (approximately 20% relative difference between SE-T2 and DESS-T2); and varied between 0.429 and 0.514 in the volunteer study. Measurements in patients showed comparable results for both techniques with regard to zonal assessment. This DESS-T2 approach represents an opportunity to combine morphological and quantitative cartilage MRI in a rapid one-step examination.

Quantitative T2 mapping of matrix-associated autologous chondrocyte transplantation at 3 Tesla: an in vivo cross-sectional study

OBJECTIVES

To evaluate magnetic resonance (MR) T2 mapping for characterization of cartilage repair tissue following matrix-associated autologous cartilage transplantation (MACT).

MATERIALS AND METHODS

Fifteen patients were evaluated following MACT using a 3T MR scanner. Patients were categorized into 2 postoperative intervals: I: 3-13 months, II: 19-42 months. Mean T2 relaxation times calculated from multiple spin-echo sequence were determined in regions of interest (MACT and normal hyaline cartilage) and T2 line profiles through the repair tissue and control sites were acquired.

RESULTS

Mean global T2 values of repair tissue in group I were significantly higher than at control sites (P < 0.05). Repair tissue in group II showed no significant difference to control sites. Repair tissue T2 line profiles normalized over time toward the control sites.

CONCLUSIONS

T2 mapping allows visualization of cartilage repair tissue maturation. Global T2 repair tissue values approach that of control sites after more than 1.5 years, similar behavior is seen in the zonal organization.

Simultaneous segmentation of multiple closed surfaces using optimal graph searching

This paper presents a general graph-theoretic technique for simultaneously segmenting multiple closed surfaces in volumetric images, which employs a novel graph-construction scheme based on triangulated surface meshes obtained from a topological presegmentation. The method utilizes an efficient graph-cut algorithm that guarantees global optimality of the solution under given cost functions and geometric constraints. The method's applicability to difficult biomedical image analysis problems was demonstrated in a case study of co-segmenting the bone and cartilage surfaces in 3-D magnetic resonance (MR) images of human ankles. The results of our automated segmentation were validated against manual tracings in 55 randomly selected image slices. Highly accurate segmentation results were obtained, with signed surface positioning errors for the bone and cartilage surfaces being 0.02 +/- 0.11mm and 0.17 +/- 0.12mm, respectively.

Treatment results of pathological fractures of the long bones: a retrospective analysis of 88 patients

Due to the advances in oncological therapy, the life expectancy of patients with malignant tumours and the incidence of pathological fractures have increased over the last decades. Pathological fractures of the long bones are common complications of metastatic disease; however, the outcome of different surgical techniques for the treatment of these fractures has not been clearly defined. The aim of this study was to evaluate differences in patient's survival and postoperative complications after the treatment of pathological fractures of the long bones. Eighty-eight patients with 96 pathological fractures of the long bones were analysed retrospectively. Seventy-five patients with 83 fractures received surgical treatment. The operative treatments used were intramedullary fixation, gliding screws, plate osteosynthesis or arthroplasty. Five patients were still alive at the end of data collection at a median time of 42.5 months, and 16.2% survived 1 year, 7% 2 years and 4% more than 3 years postoperatively. All surgically treated patients had a reduction of local pain and were able to walk after the operation. The overall rate of complications was 8%. Early palliative treatment of pathological fractures of the long bones is indicated in most patients in the advanced stage of metastatic disease. The low complication rate, reduction of local pain and early mobilisation justify the surgical stabilisation of fractures in this cohort of patients.

Development of injury criteria for pelvic fracture in frontal crashes

OBJECTIVE

This article assesses the position-dependent injury tolerance of the hip in the frontal direction based on testing of eight postmortem human subjects.

METHODS

For each subject, the left and right hemipelvis complex was axially loaded using a previously developed test configuration. Six positions were defined from a seated femur neutral condition, combining flexed, neutral, and extended femur positions with abducted, neutral, and adducted positions.

RESULTS

Axial injury tolerances based on peak force were found to be 6,850 +/- 840 N in the extended, neutral position and 4,080 +/- 830 N in the flexed, neutral position. From the flexed neutral orientation, the peak axial force increased 18% for 20 degrees abduction and decreased 6% for 20 degrees adduction. From the extended, neutral orientation, the peak axial force decreased 4% for 20 degrees abduction and decreased 3% for 20 degrees adduction. However, as there is evidence that increases in loading may occur after the initiation of fracture, the magnitude of the peak force is likely related to the extent of injury, not to the initial tolerance. Using the axial femur force at the initiation of fracture (assessed with acoustic crack sensors) as a potentially more relevant indicator of injury may lower the existing injury criteria. This fracture initiation force varied by position from 3,010 +/- 560 N in the flexed, neutral position to 5,470 N in the extended, abducted position. Further, there was a large position-dependent variation in the ratio of fracture initiation force to the peak axial force. The initiation of fracture was 83% of the peak axial force in the extended, abducted position, but the ratio was 34% in the extended, adducted position.

CONCLUSIONS

This may have significant implications for the development of pelvic injury criteria by automobile designers attempting to mitigate pelvis injuries.

Surface extraction and thickness measurement of the articular cartilage from MR images using directional gradient vector flow snakes

The accuracy of the surface extraction of magnetic resonance images of highly congruent joints with thin articular cartilage layers has a significant effect on the percentage errors and reproducibility of quantitative measurements (e.g., thickness and volume) of the articular cartilage. Traditional techniques such as gradient-based edge detection are not suitable for the extraction of these surfaces. This paper studies the extraction of articular cartilage surfaces using snakes, and a gradient vector flow (GVF)-based external force is proposed for this application. In order to make the GVF snake more stable and converge to the correct surfaces, directional gradient is used to produce the gradient vector flow. Experimental results show that the directional GVF snake is more robust than the traditional GVF snake for this application. Based on the newly developed snake model, an articular cartilage surface extraction algorithm is developed. Thickness is computed based on the surfaces extracted using the proposed algorithm. In order to make the thickness measurement more reproducible, a new thickness computation approach, which is called T-norm, is introduced. Experimental results show that the thickness measurement obtained by the new thickness computation approach has better reproducibility than that obtained by the existing thickness computation approaches.

Matrix-based autologous chondrocyte implantation for cartilage repair with Hyalograft®C: Two-year follow-up by magnetic resonance imaging

OBJECTIVE

Monitoring of articular cartilage repair after matrix-associated autologous chondrocyte implantation with HyalograftC by a new grading system based on non-invasive high-resolution magnetic resonance imaging.

PATIENTS AND METHODS

In 23 patients, postoperative magnetic resonance imaging (MRI) was performed between 76 and 120 weeks. In nine of these patients, five MRI examinations were performed at 4, 12, 24, 52 and 104 weeks after HyalograftC implant. The repair tissue was described with separate variables: degree of defect repair in width and length, signal intensity of the repair tissue and status of the subchondral bone. For these variables a grading system with point scale evaluation was applied.

RESULTS

CONCLUSION

High-resolution MRI provides a non-invasive tool for monitoring the development of cartilage repair tissue following HyalograftC technology, shows a good correlation with clinical outcome and may help to differentiate abnormal repair tissue from a normal maturation process.

Matrix-based autologous chondrocyte implantation for cartilage repair with HyalograftC: two-year follow-up by magnetic resonance imaging

OBJECTIVE

Monitoring of articular cartilage repair after matrix-associated autologous chondrocyte implantation with HyalograftC by a new grading system based on non-invasive high-resolution magnetic resonance imaging.

PATIENTS AND METHODS

In 23 patients, postoperative magnetic resonance imaging (MRI) was performed between 76 and 120 weeks. In nine of these patients, five MRI examinations were performed at 4, 12, 24, 52 and 104 weeks after HyalograftC implant. The repair tissue was described with separate variables: degree of defect repair in width and length, signal intensity of the repair tissue and status of the subchondral bone. For these variables a grading system with point scale evaluation was applied.

RESULTS

CONCLUSION

High-resolution MRI provides a non-invasive tool for monitoring the development of cartilage repair tissue following HyalograftC technology, shows a good correlation with clinical outcome and may help to differentiate abnormal repair tissue from a normal maturation process.

Treatment of posttraumatic adhesive capsulitis of the ankle: a case series

BACKGROUND

Adhesive capsulitis of the ankle is a challenging diagnostic and therapeutic problem. Limited information concerning diagnosis and treatment is available in the musculoskeletal literature.

METHODS

This study retrospectively reviewed a series of patients treated with corticosteroid injections or arthroscopic debridement of posttraumatic adhesive capsulitis of the ankle. The Foot Function Index was used to assess the final treatment outcomes.

RESULTS

Forty-one patients with chronic posttraumatic ankle pain were identified. Five were confirmed to have posttraumatic adhesive capsulitis by arthrogram. Four of the five patients failed to respond to steroid injections and three had arthroscopic surgery. Foot Function Index scores indicated that two of these patients treated with arthroscopic debridement had improved function.

CONCLUSIONS

Results of small series and information from the literature suggest that intra-articular injection of corticosteroid followed by arthroscopic synovectomy and scar resection can be effective as treatment for posttraumatic adhesive capsulitis of the ankle.

Injury tolerance and response of the ankle joint in dynamic dorsiflexion

Forced dorsiflexion in frontal vehicle crashes is considered a common cause of injury to the ankle joint. Although a few studies have been published on the dynamic fracture tolerance of the ankle in dorsiflexion, this work reexamines the topic with increased statistical power, adds an evaluation of articular cartilage injury, and utilizes methods to detect the true time of fracture. The objective of this study was to measure the response and injury tolerance of the human ankle in a loading condition similar to that found in a vehicle crash with toepan intrusion. A test fixture was constructed to apply forefoot impacts to twenty cadaveric lower limbs, that were anatomically intact distal to the femur mid-diaphysis. Specimen instrumentation included implanted tibial and fibular load cells, accelerometers, angular rate sensors, and an acoustic sensor. Following the tests, specimens were radiographed and dissected to determine the extent of injury. Eleven of the twenty specimens sustained fracture of the ankle joint. Fractures of the medial malleolus were the most common, while two specimens sustained bimalleolar fractures, and two a talar neck fracture. Other injuries included ligament tears, osteochondral fractures, and cartilage abrasions. Analysis of the acoustic emission indicated that fracture did not always occur at the peak ankle moment. Based on the results of this study, an ankle joint moment of 59 N-m represents a 25% risk of ankle fracture in dorsiflexion for a 50(th) percentile male. When applied to the Thor-Lx dummy, the 25% risk of injury occurs at 36 degrees of dorsiflexion as measured by the ankle potentiometer.

Mode of action and application of Scorpion primers to mutation detection

Scorpion primers can be used to detect PCR products in homogeneous solution. Their structure promotes a unimolecular probing mechanism. We compare their performance with that of the same probe sequence forced to act in a bimolecular manner. The data suggest that Scorpions indeed probe by a unimolecular mechanism which is faster and more efficient than the bimolecular mechanism. This mechanism is not dependent on enzymatic cleavage of the probe. A direct comparison between Scorpions, TaqMan and Molecular Beacons on a Roche LightCycler indicates that Scorpions perform better, particularly under fast cycling conditions. Development of a cystic fibrosis mutation detection assay shows that Scorpion primers are selective enough to detect single base mutations and give good sensitivity in all cases. Simultaneous detection of both normal and mutant alleles in a single reaction is possible by combining two Scorpions in a multiplex reaction. Such favourable properties of Scorpion primers should make the technology ideal in numerous applications.

Arthropod toxins as leads for novel insecticides: an assessment of polyamine amides as glutamate antagonists

In the search for new toxins, preferably with new sites of action, the polyamine amides represent a new class of compounds with potential as insecticides and as pharmaceutical agents due to their antagonism of ligand-gated cation channels. In particular, they are potent antagonists of the L-glutamate receptors of insect skeletal muscle. In this paper, we report on synthetic studies to produce hybrid analogues based upon the argiotoxin spider toxins and philanthotoxin-433 which is obtained from a solitary, parasitic wasp. We speculate upon possible modes and sites of action for these antagonists and we discuss their potential as insecticides and in the possible treatment of ischaemic damage. The synthesis and characterization of 4-hydroxyphenylpropanoylspermine is reported and the locust muscle biological assay is described. Using this pharmacological screen, structure-activity relationships have been determined in our laboratories. These are reviewed in the light of the current literature. Voltage clamp studies of the synthetic analogue philanthotoxin-343 and the effects of this polyamine amide on glutamate receptors expressed in Xenopus oocytes are outlined. In conclusion, a description of our current ideas and understanding of the many sites and modes of action of the polyamine amides, based both upon our own studies and also upon those recently reported, is presented.