Accuracy of CT-guided joint aspiration in patients with suspected infection status post-total hip arthroplasty

Objective

To determine the accuracy of guided computed tomography aspiration in the detection of septic hip prosthesis before surgery.

Materials and Methods

Sixty-three patients (35 women and 28 men; age range, 29?C86?years; mean age, 71?years) with clinically suspected septic hip prosthesis were prospectively studied with independent review board (IRB) approval. Volume and microbiological cultures of aspirated fluid and several computed tomography imaging findings such as periprosthetic fluid collections, prosthetic acetabular malposition, and heterotopic ossification were analyzed. All patients underwent revision surgery and infection was finally diagnosed in 33 patients.

Results

Statistical comparative analysis was performed comparing computed tomography aspiration and surgical findings (95% CI; level of significance at P?=?0.05 two-sided) with 70% sensitivity, 100% specificity, 84% accuracy, 100% positive predictive value, and 75% negative predictive value. Using Fisher??s exact test, the presence of periprosthetic fluid collections (P?=?0.001), prosthetic acetabular malposition (P?=?0.025) and aspirated fluid volume (P?=?0.009) were significantly higher in infected than in non-infected prostheses, whereas heterotopic ossification was not (P?=?0.429).

Conclusion

Computed tomography aspiration is accurate to preoperatively diagnose septic hip prosthesis on the basis of volume and bacterial cultures of aspirated joint fluid. Furthermore, imaging findings such as periprosthetic fluid collections and prosthetic acetabular malposition strongly suggest infected prosthesis.     

FDG and FDG-labelled leucocyte PET/CT in the imaging of prosthetic joint infection

Purpose

The demand for arthroplasty is rapidly growing as a result of the ageing of the population. Although complications such as heterotrophic ossification, fracture and dislocation are relatively rare, differentiating aseptic loosening, the most common complication of arthroplasty from infection, is a major challenge for clinicians. Radionuclide imaging is currently the imaging modality of choice since it is not affected by orthopaedic hardware. Whereas FDG PET/CT imaging has been widely used in periprosthetic infection, it cannot discriminate aseptic from septic inflammation. In this study we aimed to evaluate the role of FDG PET/CT and FDG-labelled leucocyte PET/CT in the diagnosis of periprosthetic infection.

Methods

Of 54 patients with painful joint arthroplasty who were imaged by FDG PET/CT for diagnosis of periprosthetic infection examined, 46 (36 women, 10 men; mean age 61.04?±?12.2 years, range 32 – 89 years) with 54 painful joint prostheses (19 hip, 35 knee) with grade 2 (above liver uptake) FDG accumulation on FDG PET/CT were included in the study and these 46 patients also underwent FDG-labelled leucocyte PET/CT. Final diagnoses were made by histopathological-microbiological culture or clinical follow-up.

Results

The final diagnosis showed infection in 15 (28 %) and aseptic loosening in 39 (72 %) of the 54 prostheses. FDG PET/CT was found to have a positive predictive value of 28 % (15/54). Since patients with no FDG uptake on FDG PET/CT were excluded from the study, the sensitivity, specificity, negative predictive value and accuracy could not be calculated. The sensitivity, specificity, and positive and negative predictive values of FDG-labelled leucocyte PET/CT were 93.3 % (14/15), 97.4 % (38/39), 93.3 % and 97.4 %, respectively.

Conclusion

Since FDG is not specific to infection, the specificity of FDG PET/CT was very low. FDG-labelled leucocyte PET/CT with its high specificity may be a useful method and better than labelled leucocyte scintigraphy in periprosthetic infection imaging.     

Fluoroscopy- vs ultrasound-guided aspiration techniques in the management of periprosthetic joint infection: which is the best?

Background

Fluid samples obtained from an affected joint still play a central role in the diagnosis of periprosthetic joint infection (PJI). It is the only preoperative test able to discover the causative microbiological agent. In the hip, fluid aspiration can be performed through fluoroscopy, ultrasound, or, less commonly, computed tomography. However, there is still a lack of consensus on which method is preferable in terms of efficacy and costbenefit.

Purposes

We, therefore, asked whether (1) the benefits in terms of sensitivity and specificity and (2) the costs were comparable between fluoroscopy- and ultrasound-guided joint aspirations in a suspicious of hip PJI.

Methods

Between 2013 and 2016, 52 hip aspirations were performed on 49 patients with clinical, radiological, or serological suspicion of PJI, waiting for a revision surgery. The patients were divided in two groups: fluoroscopy- (n = 26) vs ultrasound-guided hip aspiration group (n = 26). These groups were also divided in control and infected patients. The criteria of MusculoSkeletal Infection Society (MSIS) were used, as gold standard, to define PJI.

Results

(1) Ultrasound-guided aspiration revealed valid sensitivity (89% vs 60%) and specificity (94% vs 81%) in comparison with fluoroscopic-guided aspiration. (2) The cost analysis was also in favor of ultrasound-guided aspiration (125.30€) than fluoroscopic-guided aspiration (343.58€).

Conclusions

We concluded that ultrasound-guided hip aspiration could represent a valid, safe, and less expensive diagnostic alternative to fluoroscopic-guided aspiration in hip PJI.

     

Diagnostic yield of CT-guided sampling in suspected sternoclavicular joint infection

Objective

To determine the prevalence of infection diagnosed by percutaneous computed tomography (CT)-guided sternoclavicular (SC) sampling in cases of suspected joint infection.

Materials and Methods

A retrospective search was performed in reports of SC joint CT-guided biopsies in adults from July 1992 to July 2012. We reviewed medical records, radiology, microbiology, laboratory, and surgical reports. A positive result was defined as demonstration of a pathogenic organism, either by microscopy or growth in culture, confirming the diagnosis of SC joint infection. A negative result was defined as the absence of such findings. Patients in whom sampling was unsuccessful or not subjected to microbiology were excluded. In addition, CT images were reviewed by the consensus of two musculoskeletal radiologists.

Results

A total of 41 patients (mean age 57.1 years) underwent CT-guided SC joint sampling, 27 of whom underwent microbiology studies. Sampling was performed using core biopsy alone in 19 %, fine needle aspiration alone in 44 %, and aspiration combined with core biopsy in 37 %. Positive results were found in 52 % (14/27) of patients. Related diseases and predisposing conditions for infection were found in 79 % of positive patients. Negative results were found in 48 % (13/27) of patients. There were no procedure-related complications. The dominant CT findings were soft tissue swelling (negative group), and effusion and/or capsular hypertrophy/distension (positive group).

Conclusions

CT-guided sampling is a safe procedure with positive microbiological cultures in slightly more than half of cases.     

Penetration of topical diclofenac sodium 4 % spray gel into the synovial tissue and synovial fluid of the knee: a randomised clinical trial

Purpose

The present study was designed to evaluate the penetration of diclofenac sodium 4 % spray gel in synovial tissue, synovial fluid and blood plasma after topical application in subjects with joint effusions and planned total knee arthroplasty (TKA) due to osteoarthritis.

Methods

A total of 39 patients were randomised to two- or three-times daily application of diclofenac sodium 4 % spray gel to knees requiring surgery over a treatment period of 3 days. Within 8 h after the last application, TKA was conducted, and the diclofenac concentrations in synovial tissue, synovial fluid and blood plasma were measured by liquid chromatography.

Results

The median diclofenac concentration was approximately 10–20-fold higher in synovial tissue (36.2 and 42.8 ng/g) than in synovial fluid (2.6 and 2.8 ng/mL) or plasma (3.9 and 4.1 ng/mL) in both treatment groups. Dose proportionality for any compartment or treatment groups could not be detected. Treatment-related adverse events were noted in two cases and limited to skin reactions.

Conclusion

Diclofenac sodium 4 % spray gel was found to penetrate the skin locally in substantial amounts and thus reach the desired target tissue. Concentrations were not dose-dependent, and application was well tolerated by 97.4 % of patients. Topical application of diclofenac should be considered a valuable alternative to systemic NSAID therapy in the initial treatment of osteoarthritis.     

The role of needle biopsy for focal bone lesions with complete fluid-fluid levels on magnetic resonance imaging

Objective

To assess the value of image-guided needle biopsy of bone lesions completely filled with fluid–fluid levels (FFLs) on magnetic resonance imaging (MRI) and the safety of primary surgical curettage.

Materials and methods

The radiology database was searched for all reports containing “fluid level” from 1998 to 2011 and the imaging was reviewed retrospectively. Inclusion criteria were patients with bone lesions completely filled with FFLs on MRI (defined as FFLs on every axial and/or sagittal T2-weighted or Short Tau Inversion Recovery (STIR) sequence). The pathology database was then reviewed for the outcome of needle biopsy (n?=?14) and for the outcome of surgical curettage, either post-biopsy or primary (n?=?52).

Results

There were 53 patients (mean age 18 years; M?=?34, F?=?19). Fourteen patients underwent percutaneous needle biopsy, which was diagnostic in five (36 %) and non-diagnostic in nine (64 %). Fifty-two patients had surgical curettage/resection, which was diagnostic in 50 (96 %) and non-diagnostic in two (4 %). All lesions were benign; 78 % were aneurysmal bone cysts (ABC), 8 % were lesions with ABC change, and 14 % were simple bone cysts.

Conclusions

Our results suggest that patients with bone lesions completely filled with FFLs on MRI are almost certain to be benign, provided that the clinical and radiological features are not atypical. Percutaneous needle biopsy in such cases is unlikely to be of value and these lesions can be safely managed with primary surgical curettage.     

A multimodal approach in total hip arthroplasty preoperative templating

Objectives

Accurate preoperative planning is mandatory for a successful total hip arthroplasty (THA). Templating helps to achieve multiple technical goals, including offset restoration, leg-length equality, and components positioning. This study aims to measure how successful a new stepwise method for preoperative radiographic templating is in achieving postoperative restoration of anatomy.

Methods

We measured the relationship of several radiographic landmarks on the affected limb in comparison to the unaffected limb to define the appropriate position of the components. One hundred consecutive patients with unilateral disease undergoing THA were retrospectively analyzed. The preoperative templates were compared with the postoperative radiographs.

Results

Accuracy in achieving the desired offset, leg-length discrepancy within 5 mm, was 93 % and 100 % respectively. Acetabular component positioning within 2° was replicated in 92 %.

Conclusion

We conclude that this technique can help the surgeon to accurately reproduce the anatomy of the contralateral unaffected hip.     

Fibronectin–aggrecan complex as a marker for cartilage degradation in non-arthritic hips

Purpose

To report hip synovial fluid cytokine concentrations in hips with and without radiographic arthritis.

Methods

Patients with no arthritis (Tonnis grade 0) and patients with Tonnis grade 2 or greater hip osteoarthritis (OA) were identified from patients undergoing either hip arthroscopy or arthroplasty. Synovial fluid was collected at the time of portal establishment for those undergoing hip arthroscopy and prior to arthrotomy for the arthroplasty group. Analytes included fibronectin–aggrecan complex (FAC) as well as a standard 12 cytokine array. Variables recorded were Tonnis grade, centre-edge angle of Wiberg, as well as labrum and cartilage pathology for the hip arthroscopy cohort. A priori power analysis was conducted, and a Mann–Whitney U test and regression analyses were used with an alpha value of 0.05 set as significant.

Results

Thirty-four patients were included (17 arthroplasty, 17 arthroscopy). FAC was the only analyte to show a significant difference between those with and without OA (p < 0.001). FAC had significantly higher concentration in those without radiographic evidence of OA undergoing microfracture versus those not receiving microfracture (p < 0.05).

Conclusion

There was a significantly higher FAC concentration in patients without radiographic OA. Additionally, those undergoing microfracture had increased levels of FAC. As FAC is a cartilage breakdown product, no significant amounts may be present in those with OA. In contrast, those undergoing microfracture have focal area(s) of cartilage breakdown. These data suggest that FAC may be useful in predicting cartilage pathology in those patients with hip pain but without radiographic evidence of arthritis.

Level of evidence

Diagnostic, Level III.     

Use of a custom alignment guide to improve glenoid component position in total shoulder arthroplasty

Purpose

Total and reverse total shoulder arthroplasty (TSA) are used to treat patients with glenohumeral joint osteoarthritis. The revision rate remains high compared with hip and knee arthroplasty. Glenoid component loosening is an important complication and may be caused by poor positioning of the component. We aimed to evaluate the safety and accuracy of a custom glenoid jig created using preoperative computed tomography (CT) imaging with 3D modelling for glenoid component implantation.

Methods

Preoperative CT scans of each shoulder (N = 7) were obtained. Implants were virtually aligned and custom templates were created for intraoperative use. A two-part custom jig was manufactured for alignment of the central peg and the peripheral screws. Three-dimensional orientation of the component and screws was evaluated in postoperative CT scans. The difference between the preoperative plan and the result was then calculated.

Results

No technical difficulties or complications occurred. The mean absolute difference between the planned alignment and the postoperative placement of the glenoid component in the three-dimensional space was 3.4 mm (SD = 1 mm). The total average difference for all screws (N = 10) was 6.3° (SD = 3.2°).

Conclusion

A CT-based custom glenoid component alignment can reliably guide the placement of the glenoid component during conventional and reverse TSA. This custom jig may be useful for optimizing glenoid component position in the setting of reverse and TSA.

Level of evidence

IV.     

Distal femur and proximal tibia replacement with megaprosthesis in revision knee arthroplasty: a limb-saving procedure

Purpose

The aim of the present study was to assess whether using megaprostheses in revision knee arthroplasty procedures allows limb salvage with an acceptable outcome and complication rate, in comparison with other limb-saving procedures.

Methods

Between 2000 and 2010, megaprosthesis implantation was required for non-oncologic indications in 20 patients (21 knees) (average age 73 years). Reconstructions involved the distal femur (n = 15), proximal tibia (n = 4), and both femur and tibia (n = 2). The indications, type, and numbers of previous operations and implants, as well as complications associated with megaprosthesis implantation, were reviewed, and the clinical and radiographic outcomes after an average follow-up period of 34 months (range 10–84 months) were evaluated.

Results

The indications for megaprosthesis implantation were periprosthetic infection (n = 5), fracture (n = 9), nonunion (n = 5), and aseptic loosening (n = 2). The types of implant placed before the megaprosthetic reconstruction were a cemented rotating-hinge arthroplasty (n = 16) and a primary total knee arthroplasty (n = 5). Six patients had an additional osteosynthesis of the distal femur. An average of 3.8 operations (range 1–7) had been carried out before megaprosthesis implantation. Complications developed in 11 patients. The Knee Society Score improved significantly, from 43 (±15) to 68 (±16.8); P < 0.05.

Conclusions

Megaprosthesis implantation in revision knee arthroplasty is an exceptional indication. Despite the high complication rate, the patients can be spared amputation in most cases, and rapid mobilization with full weight-bearing is possible.     

Revision hip arthroscopic surgery: outcome at three years

Purpose

This study describes the medium-term results of revision hip arthroscopy.

Methods

Patients with persistent hip pain and a positive impingement sign were considered for revision surgery after the exclusion of other causes of groin pain. Seventy-four consecutive patients were prospectively assessed using the modified Harris hip score for a period of 3 years after surgery. Of the 74 patients, 11 had inadequate follow-up data; thus, a total of 63 patients were qualified for the study. The mean age at index surgery was 37 years, comprising 27 males and 36 females.

Results

Revision surgery was performed at a mean of 3 years from index surgery. Chondral lesion associated with labral re-injury was the most common finding at revision arthroscopy. In contrast to other authors, however, only 31 % of our patients underwent revision for persistent femoroacetabular impingement. The mean pre-operative mHHS for all 63 patients was 54 (SD 14.5). The mean post-operative mHHS was 53 (SD 14.9) at 6 weeks, 62 (SD 17.5) at 6 months, 63 (SD 16.5) at 1 year, 64 (SD 16.5) at 2 years and 59 (SD 16.5) at 3 years (p = n.s., 0.02, 0.045, 0.039 and n.s., respectively).

Conclusions

Revision arthroscopy results in improvement in outcome in the first 3 years after revision surgery with a success rate of 63.4 % at 1 year, falling to 55.6 % by 3 years.

Level of evidence

IV.     

Occurrence of coring after needle insertion through a rubber stopper: study with prednisolone acetate

Objectives

To evaluate the occurrence of coring after needle insertion through the rubber stopper of prednisolone acetate vials.

Methods

Two-hundred vials of prednisolone acetate were randomly distributed to two radiologists. Prednisolone acetate was drawn up through the rubber bung of the vials with an 18-gauge cutting bevelled needle and aspirated with a 5-ml syringe. The presence of coring was noted visually. We systematically put each core in a syringe refilled with 3 ml prednisolone acetate, and injected the medication through a 20-gauge spine needle. Computed tomography was performed to measure the size of each coring.

Results

Coring occurred in 21 out of 200 samples (10.5 %), and was visually detected in the syringe filled up with prednisolone in 11 of the 21 cases. Ten more occult cores were detected only after the syringes and needles were taken apart and rinsed. The core size ranged from 0.6 to 1.1 mm, and 1 of the 21 (4.7 %) cores was ejected through the 20-gauge needle.

Conclusion

Coring can occur after the insertion of a needle through the rubber stopper of a vial of prednisolone acetate, and the resultant core can then be aspirated into the syringe.

Key Points

? Coring occurs after needle insertion through rubber stoppers of prednisolone acetate vials ? Cores within a syringe filled with prednisolone acetate may be undetected ? The frequency of coring during the administration of prednisolone acetate is underestimated     

Infection and revision rates following primary total knee arthroplasty in patients with rheumatoid arthritis versus osteoarthritis: a meta-analysis

Purpose

This meta-analysis compared infection and revision rates in patients with rheumatoid arthritis (RA) and osteoarthritis (OA) who underwent total knee arthroplasty (TKA). Rates of superficial wound and deep periprosthetic infections were compared in the groups, as were whether revision rates associated with infectious and noninfectious causes differed in the RA and OA groups.

Methods

Studies were included in the meta-analysis if they (1) compared infection and revision rates after primary TKA in RA and OA patients; (2) directly compared superficial wound and deep periprosthetic infection rates in RA and OA patients who underwent primary TKA; and (3) reported the actual numbers of RA and OA patients who underwent TKA and developed postoperative infection and/or required revision.

Results

The rate of superficial wound infections after primary TKA was similar in the RA and OA groups (15/258 [5.8 %] vs. 77/1609 [4.7 %]; odds ratio [OR] 1.12, 95 % confidence interval [CI] 0.36–3.46; P = n.n.), but the deep infection rate was significantly higher in RA than in OA patients (229/7651 [3.0 %] vs. 642/68628 [0.9 %]; OR 2.04, 95 % CI 1.37–3.05; P < 0.001). The proportion of subjects who required revision resulting from infection after TKA was significantly higher in the RA than in the OA group (86/8201 [1.0 %] vs. 555/118755 [0.5 %]; OR 1.89, 95 % CI 1,34–2.66; P < 0.001), whereas the proportion of subjects requiring revision due to noninfectious causes did not differ significantly (46/594 [7.7 %] vs. 52/904 [5.7 %]; OR 1.22, 95 % CI 0.74–2.00; P = n.n.)

Conclusion

Following primary TKA, RA patients had a significantly higher rate of deep periprosthetic infections than OA patients, but their superficial infection rates were similar. The revision rate due to infectious causes was significantly higher in RA than in OA patients, but their revision rates due to noninfectious causes did not differ. Therefore, the surgeon should fully explain to RA patients scheduled to undergo primary TKA that, compared to OA patients, they are more likely to experience a deep infection postsurgery.

Level of evidence

Meta-analysis Level III.

     

Microorganisms responsible for periprosthetic knee infections in England and Wales

Purpose

This study aimed to delineate epidemiology of infecting microorganism genus in first-time revision knee arthroplasty for indication of periprosthetic joint infection in England and Wales using linked registry data.

Methods

From the National Joint Registry database for England and Wales, a consecutive series of primary knee arthroplasties performed between April 2003 and January 2014 that went on to have a revision for periprosthetic infection were identified (n = 2810). Each case was then linked to microbiology data held by Public Health England in order to identify infecting microorganism at time of revision surgery established from intra-operative cultures. Following data linkage, 403 culture results at time of revision surgery were identified in a group of 331 patients. The demographic characteristics of five microorganism groups were compared: pure staphylococcus (single genus), pure streptococcus (single genus), other gram-positive infections (single genus), gram-negative infections (single genus) and mixed genus infections.

Results

Staphylococcus species was the most common organism genus isolated after revision of a primary implant for infection and present in 72 % of cases overall (71.3 % of patients with a single-genus infection and 76.8 % of patients with mixed genus infection). A pure staphylococcal infection was present in 59 % of all cases. A single-genus infection was responsible for infection in 83.1 % of cases, and mixed genera were responsible in 16.9 % of cases. A significant difference was observed for mean age at primary procedure in the cohort of patients where there was an isolated pure streptococcal infection (73.2 years) when compared to gram-negative infections (65.0 years). No other significant differences were observed between microorganism groups in terms of BMI, gender, ASA grade, indication for primary procedure and primary implant characteristics.

Conclusion

Staphylococci were the most commonly isolated organism species responsible for periprosthetic infection of primary arthroplasty in England and Wales. This information can be used by surgeons to benchmark and audit their own practice against national, publicly available data. Furthermore, this study has shown that even when using the largest national databases available, there is a substantial volume of missing data. Antimicrobial resistance represents a growing clinical problem with significant health and social costs. In order to counteract this threat, this study would advocate the consolidation of national microbial data in order to guide effective strategies towards targeting and combating the threat of antimicrobial resistance.

Level of evidence

IV.

     

Intra-articular adhesions following hip arthroscopy: a risk factor analysis

Purpose

The purpose of this study was to evaluate possible risk factors for symptomatic adhesions after hip arthroscopy.

Methods

Data were analysed from hip arthroscopies performed between 2005 and 2009. Only primary hip arthroscopies were included. Data collected included demographics, primary treatment, rehabilitation, revision surgery, and presence of adhesions at revision.

Results

One thousand two hundred and sixty-four hips in patients 18 years or older underwent primary hip arthroscopy during the defined period. Eight underwent revision hip arthroscopy by a different surgeon. Patients under 30 years of age were 5.9 times more likely to be in the adhesion group [95 % CI 3.1–11.5]. Patients who underwent microfracture were 3.1 times less likely to have adhesions compared to patients who did not [95 % CI 1.1–8.2]. Patients who did not receive circumduction therapy were 4.1 times more likely to have adhesions compared to those who performed circumduction exercises [95 % CI 1.25–11.0].

Conclusion

Risk factors for adhesions following hip arthroscopy identified were age under 30, modified Harris Hip score under 50, no microfracture performed, and rehabilitation without circumduction.

Level of evidence

IV.     

MR-guided stereotactic breast biopsy using a mixed ferromagnetic-nonmagnetic coaxial system with 12- to 18-gauge needles: clinical experience and long-term outcome

Purpose

This study investigated the clinical application of a magnetic-resonance (MR)-guided breast biopsy (MRBB) system consisting of a nonmagnetic coaxial needle and a ferromagnetic core biopsy needle.

Materials and methods

MRBB was performed on 70 breast lesions. The biopsy device consisted of a nonmagnetic 14- to 16-gauge coaxial needle and a ferromagnetic 16- to 18-gauge biopsy needle.

Results

Of the 70 lesions, 29 were malignant and 41 nonmalignant. All 29 malignant lesions underwent surgery and were confirmed as malignant at final histology. Of the 41 nonmalignant lesions, 35 underwent follow-up breast MR imaging (mean, 26±19 months), which demonstrated no lesions changes; six lesions underwent surgery because of poor radiological-pathological correlation; of these 6 lesions, 3 were nonmalignant, one was borderline (lobular carcinoma in situ) and two were malignant (well-differentiated tubular carcinoma and infiltrating ductal carcinoma). Sensitivity, specificity, positive and negative predictive values and diagnostic accuracy were, respectively, 93.5%, 100%, 100%, 95.1% and 97.1% if the lobular carcinoma in situ was considered a nonmalignant histological result, and 90.6%, 100%, 100%, 92.7% and 95.7% if the lobular carcinoma in situ was considered malignant.

Conclusions

MRBB with a ferromagnetic-nonmagnetic coaxial system represented an easy way to perform a biopsy procedure and was easily applicable in the routine clinical setting.     

Revision total knee arthroplasty with varus–valgus constrained prosthesis versus posterior stabilized prosthesis

Purpose

The aims of this retrospective study were to provide the basis for the choice of prosthesis in revision total knee arthroplasty (TKA) and to evaluate the outcome with varus–valgus constrained prosthesis compared with posterior stabilized (PS) prosthesis.

Methods

One hundred and five patients (121 knees) received revision TKA; of which thirty-seven patients (42 knees) received PS prosthesis and sixty-eight patients (79 knees) received varus–valgus constrained prosthesis. The mean follow-up duration was 64.8 ± 31.5 months and 63.2 ± 28.1 months in the PS and varus–valgus constrained groups, respectively. The criterion of prosthesis choice was a subjective laxity assessed by the surgeon intraoperatively. A multivariate analysis was performed to evaluate the preoperative factors in the choice of the prosthesis.

Results

The grade of femoral bone defect was the only factor that affected the choice of prosthesis. Clinical results improved significantly in both groups after surgery. There were no significant differences in clinical results between the two groups. Complication rates were 9.5 % in the PS group and 10.1 % in the varus–valgus constrained group, and the Kaplan–Meier survivorship analysis revealed 8-year component survival rates of 83.1 and 93.0 % in the PS and varus–valgus constrained groups, respectively.

Conclusions

Femoral bone defect is an important factor to be considered in the choice of prosthesis for revision TKA. The varus–valgus constrained prosthesis showed an outcome similar to that of the PS prosthesis. For clinical relevance, varus–valgus constrained prosthesis is recommended in revision TKA when the PS prosthesis seems unsuitable for the management of instability.

Level of evidence

III.     

The use of sonoelastographic elasticity index to differentiate benign and malignant thyroid nodules

Purpose

The aim of this study is to evaluate the elasticity index of thyroid nodules by sonoelastographic imaging, and to determine the cut-off value to distinguish malignant nodules from benign nodules with optimum sensitivity and specificity.

Materials and methods

Fine needle aspiration biopsy (FNAB) of 84 cases were evaluated with B-mode US and Sonoelastography (USE) preoperatively. The elasticity score (ELX 2/1) index of the nodules were calculated. Seventy-three patients with diagnostic biopsy results were included in this study.

Results

According to the FNAB results, 9 (12 %) nodules were malignant, 64 (88 %) nodules were benign. All malignant nodules were papillary carcinoma, and their diagnosis was confirmed with thyroidectomy. The ELX 2/1 index of all malignant nodules was higher than 1.65. The ELX 2/1 index of 45 (70.3 %) benign nodules was lower than 1.65 whereas the ELX 2/1 index of 19 (29.7 %) benign nodules was higher than 1.65. Using an ELX 2/1 index cut-off value of 1.65 led to a sensitivity of 100 % and a specificity of 71 % in detecting papillary thyroid carcinomas.

Conclusions

Assessing the ELX 2/1 index as a screening test and deciding on FNAB accordingly, in addition to gray-scale ultrasound findings of the nodules, will be beneficial in order to prevent unnecessary biopsies.     

Patient reported outcome measures after revision of the infected TKR: comparison of single versus two-stage revision

Purpose

Two-stage revision is the ‘gold standard’ treatment for infected total knee replacement. Single-stage revision has been successful in the hip and, in carefully chosen knee revisions, may offer the advantage of a single surgical insult with improved functional outcome.

Methods

Patient Reported Outcome Measures (PROMs) for 33 single- and 89 two-stage revisions performed for infection were analysed in combination with data from the National Joint Registry for England and Wales. Outcomes including the Oxford Knee Score (OKS), Euroqol-5D (EQ5D) and patient satisfaction were examined with the aim of investigating the following questions: does single- or two-stage revision for infection result in (1) better knee function; (2) better overall perception of health status; (3) better patient perceived success and satisfaction?

Results

No statistical difference was found between the groups for any reported outcome measure. Mean OKS following surgery was 24.9 (95 %CI, 20.5–29.4) for single- and 22.8 (95 %CI, 20.2–25.4) for two-stage (n.s.). Mean EQ5D index following surgery was 0.495 (95 %CI, 0.357–0.632) for single and 0.473 (95 %CI, 0.397–0.548) for two-stage (n.s.). Patients reporting Excellent/Very good/Good satisfaction were similar between the groups (single = 61 % vs. two stage = 57 %, (n.s.)). In total, 66 % single- and 60 % two-stage operations were rated ‘successful’ (n.s.).

Conclusions

This study found no demonstrable benefit of single-stage compared to two-stage revision for the infected total knee replacement using a variety of PROMs. Thus, we recommend that decision making must be based on other factors such as re-infection rate.

Level of evidence

IV.     

Real-time virtual sonography (RVS)-guided vacuum-assisted breast biopsy for lesions initially detected with breast MRI

Purpose

To report on our initial experiences with a new method of real-time virtual sonography (RVS)-guided 11-gauge vacuum-assisted breast biopsy for lesions that were initially detected with breast MRI.

Materials and methods

RVS-guided 11-gauge vacuum-assisted biopsy is performed when a lesion with suspicious characteristics is initially detected with breast MRI and is occult on mammography, sonography, and physical examination. Live sonographic images were co-registered to the previously loaded second-look spine contrast-enhanced breast MRI volume data to correlate the sonography and MR images.

Results

Six lesions were examined in six consecutive patients scheduled to undergo RVS-guided 11-gauge vacuum-assisted biopsy. One patient was removed from the study because of non-visualization of the lesion in the second-look spine contrast-enhanced breast MRI. Five patients with non-mass enhancement lesions were biopsied. The lesions ranged in size from 9 to 13 mm (mean 11 mm). The average procedural time, including the sonography and MR image co-registration time, was 25 min. All biopsies resulted in tissue retrieval. One was fibroadenomatous nodules, and those of four were fibrocystic changes. There were no complications during or after the procedures.

Conclusion

RVS-guided 11-gauge vacuum-assisted breast biopsies provide a safe and effective method for the examination of suspicious lesions initially detected with MRI.