Gender-based differences exist in the functional knee phenotypes classification of the osteoarthritic knee.

PURPOSE: To identify gender differences in (1) the coronal alignment of functional knee phenotypes and (2) the JLCA (joint line convergence angle) in relation to the phenotype classification. METHODS: This study is a retrospective data analysis, including 12,099 osteoarthritic knee computed tomography (5025 male, 7074 female) analysed by Medacta software for hip-knee-ankle angle (HKA), femoral mechanical angle (FMA), tibial mechanical angle (TMA) and JLCA. The data were grouped into genders and combined according to the Functional Knee Phenotypes Classification. RESULTS: Out of 127 phenotypes for males and 131 for females, 17 common phenotypes were reported. The commonest four were similar for both genders with VARHKA177° NEUFMA93° NEUTMA87° (9.8% males, 9.50% females), followed by VARHKA174° NEUFMA93°VARTMA84° (7.1%) and VARHKA174°VARFMA90° NEUTMA87° (7.0%) for males and VARHKA174° NEUFMA93° NEUTMA87° (6.1%), VARHKA174° NEUFMA93°VARTMA84° (5.1%) for females. The commonest FMA and TMA (91.5° to 94.5° and 85.5° to 88.5°, respectively) were the same for both genders, however, the rest of the male population observed greater femoral varus than the female population (p < 0.001). JLCA values ranged from -28.4° to 8.2° in the overall study population. Males and females had a mean JLCA of -2.96° (±2.6° SD) and -2.66° (±2.8°7 SD), respectively, p < 0.001. CONCLUSIONS: Gender differences exist within the osteoarthritic knee phenotype. The male varus phenotype is influenced by FMA, while TMA values are similar across genders. JLCA variations show similarities to both TMA and FMA, suggesting JLCA is influenced by bone morphology more than by gender. These differences inform surgical decision-making for the personalised approach to the primary TKA. LEVEL OF EVIDENCE: Level III.

Definition of normal, neutral, deviant and aberrant coronal knee alignment for total knee arthroplasty.

PURPOSE: One of the most pertinent questions in total knee arthroplasty (TKA) is: what could be considered normal coronal alignment? This study aims to define normal, neutral, deviant and aberrant coronal alignment using large data from a computed tomography (CT)-scan database and previously published phenotypes. METHODS: Coronal alignment parameters from 11,191 knee osteoarthritis (OA) patients were measured based on three dimensional reconstructed CT data using a validated planning software. Based on these measurements, patients' coronal alignment was phenotyped according to the functional knee phenotype concept. These phenotypes represent an alignment variation of the overall hip knee ankle angle (HKA), femoral mechanical angle (FMA) and tibial mechanical angle (TMA). Each phenotype is defined by a specific mean and covers a range of ±1.5° from this mean. Coronal alignment is classified as normal, neutral, deviant and aberrant based on distribution frequency. Mean values and distribution among the phenotypes are presented and compared between two populations (OA patients in this study and non-OA patients from a previously published study). RESULTS: The arithmetic HKA (aHKA), combined normalised data of FMA and TMA, showed that 36.0% of knees were neutral within ±1 SD from the mean in both angles, 44.3% had either a TMA or a FMA within ±1-2 SD (normally aligned), 15.3% of the patients were deviant within ±2-3 SD and only 4.4% of them had an aberrant alignment (±3-4 SD in 3.4% and >4 SD in 1.0% of the patients respectively). However, combining the normalised data of HKA, FMA and TMA, 15.4% of patients were neutral in all three angles, 39.7% were at least normal, 27.7% had at least one deviant angle and 17.2% had at least one aberrant angle. For HKA, the males exhibited 1° varus and females were neutral. For FMA, the females exhibited 0.7° more valgus in mean than males and grew 1.8° per category (males grew 2.1° per category). For TMA, the males exhibited 1.3° more varus than females and both grew 2.3° and 2.4° (females) per category. Normal coronal alignment was 179.2° ± 2.8-5.6° (males) and 180.5 > ± 2.8-5.6° (females) for HKA, 93.1 > ± 2.1-4.2° (males) and 93.8 > ± 1.8-3.6° (females) for FMA and 86.7 > ± 2.3-4.6° (males) and 88 > ± 2.4-4.8° (females) for TMA. This means HKA 6.4 varus or 4.8° valgus (males) or 5.1° varus to 6.1° valgus was considered normal. For FMA HKA 1.1 varus or 7.3° valgus (males) or 0.2° valgus to 7.4° valgus was considered normal. For TMA HKA 7.9 varus or 1.3° valgus (males) or 6.8° varus to 2.8° valgus was considered normal. Aberrant coronal alignment started from 179.2° ± 8.4° (males) and 180.5 > ± 8.4° (females) for HKA, 93.1 > ± 6.3° (males) 93.8 > ± 5.4° (females) for FMA and 86.7 > ± 6.9° (males) and 88 > ± 7.2° (females) for TMA. This means HKA > 9.2° varus or 7.6° valgus (males) or 7.9° varus to 8.9° valgus was considered aberrant. CONCLUSION: Definitions of neutrality, normality, deviance as well as aberrance for coronal alignment in TKA were proposed in this study according to their distribution frequencies. This can be seen as an important first step towards a safe transition from the conventional one-size-fits-all to a more personalised coronal alignment target. There should be further definitions combining bony alignment, joint surfaces' morphology, soft tissue laxities and joint kinematics. LEVEL OF EVIDENCE: III.

Use of the forgotten joint score (FJS)-12 to evaluate knee awareness after quadriceps tendon reconstruction.

BACKGROUND: Quadriceps tendon rupture (QTR) is a severe injury of the knee extensor apparatus. The study aims to validate the use of forgotten joint score (FJS-12) for functional outcome assessing after surgical treatment of QTR. METHODS: Fifty-seven patients who underwent surgery for QTR with transosseous suture reconstruction in a single orthopaedic surgery and traumatology center between 2015 and 2020 were eligible for enrolment in this retrospective case series. The demographic data and other pre-operative details such as age, gender, comorbidities and medication use also were extracted from the medical records. Patient reported outcome measures (PROMs) were gathered in the form of Western Ontario and McMaster Universities Arthritis Index Score (WOMAC), Tegner Activity Score (TAS), Lysholm Score and FJS-12 at a mean follow-up time of 49.84 months ± 20.64 months. The FJS-12 was validated by correlation with WOMAC, TAS and Lysholm Score. RESULTS: The mean age of all patients were 69.2 ± 13.6 years with 51 (89.5%) males and 6 (10.5%) females. The mean time from injury to surgery was 3.39 ± 5.46 days. All patients reported satisfactory functional outcomes after surgery on FJS-12, WOMAC and Lysholm scores, except the TAS, which decreased slightly from pre-operative level. There was a high negative correlation between WOMAC and FJS-12, but moderate positive correlations between FJS-12 and TAS and Lysholm scores. The Cronbach's alpha value was 0.96 for 12 items in FJS-12. CONCLUSION: This study has found that FJS-12 is a reliable and easy to assess tool for functional outcomes after QTR reconstruction. It has shown moderate to strong correlation with other commonly used outcome measures (WOMAC, TAS and Lysholm).

Comparative retrieval analysis of a novel anatomic tibial tray backside: alterations in tibial component design and surface coating can increase cement adhesions and surface roughness.

BACKGROUND: With the Persona® knee system a novel anatomic total knee design was developed, which has no pre-coating, whereas the predecessor knee system is pre-coated with polymethylmethacrylate (PMMA). Joint registry data have shown no decrease in risk of aseptic revision of PMMA pre-coated tibial components compared with non-pre-coated implants. The aim of this retrieval study was to compare the amount of cement adhesions, geometry and surface features between the two knee designs and to correlate them with the underlying reason for revision surgery. METHODS: Retrieval analysis was performed of 15 NexGen® and 8 Persona® fixed-bearing knee implants from the same manufacturer retrieved from two knee revision centres. A photogrammetric method was used to grade the amount of cement attached to the tibial tray backside. The geometry and dimensions of the tibial trays, tray projections and peripheral lips were measured using digital callipers and compared between the two different designs. To measure the surface roughness on the backside of the tibial tray, a contact profilometer was used. To investigate differences between the two designs statistical analyses (t-test) were performed. RESULTS: All Persona® trays showed evidence of cement adhesion with a % area of 75.4%; half of the NexGen® trays had cement adhesions, with a mean value of 20%. There was a significant difference in the percentage of area covered by cement between the two designs (p < 0.001). Results from the contact profilometer revealed that Persona® and NexGen® tray backsides showed a similar lateral (1.36 µm and 1.10 µm) and medial (1.39 µm and 1.12 µm) mean surface roughness with significant differentiation (p < 0.05) of the lateral and medial roughness values between the two designs. Persona® stems showed a significantly higher mean surface roughness (1.26) compared to NexGen® stems (0.89; p < 0.05). CONCLUSION: The novel anatomic knee system showed significantly more cements adhesions and a higher surface roughness which was most likely attributed to the most obvious design and coating alteration of the tibial tray. This study provides first retrieval findings of a novel TKA design recently introduced to the market.

Ethnical Differences in Knee Phenotypes Indicate the Need for a More Individualized Approach in Knee Arthroplasty: A Comparison of 80 Asian Knees with 308 Caucasian Knees.

The purpose of this study was to determine the distribution of functional knee phenotypes in a non-osteoarthritic Asian population. The Stryker Orthopaedic Modeling and Analytics (SOMA) database was searched for CT scans of the lower limb meeting the following inclusion criteria: patient age at time of image >18 and <46 years, no signs of fractures and/or previous surgery and/or degenerative changes, Asian ethnicity. A total of 80 CT scans of 40 patients were included (24 males, 16 females). The hip-knee-ankle angle (HKA), femoral mechanical angle (FMA) and tibial mechanical angle (TMA) were measured. Based on these measurements, each limb was phenotyped according to the previously introduced functional knee phenotype concept. All angles and phenotypes of the present study were compared with previously published data of a non-osteoarthritic Caucasian population (308 legs of 160 patients, 102 males, 58 females). Asian knees had a significantly lower TMA (both genders p < 0.001) but a higher FMA (males p < 0.05, females p < 0.001) than Caucasian knees but showed no difference in the HKA. Asian knees differed significantly with regard to femoral and tibial phenotypes (p < 0.01), but not with regard to limb phenotypes. The high variability of all coronal alignment parameters highlights the importance of a detailed analysis prior to TKA. Ethnical differences underline the need for a more individualized approach in TKA.

Diagnostics of infrapatellar saphenous neuralgia-a reversible cause of chronic anteromedial pain following knee surgery.

OBJECTIVES: To evaluate the impact of diagnostic nerve block and ultrasound findings on therapeutic choices and predict the outcome after concomitant surgery in patients with suspected neuropathy of the infrapatellar branch of the saphenous nerve (IPBSN). METHODS: Fifty-five patients following knee surgery with suspicion of IPBSN neuralgia were retrospectively included. Ultrasound reports were assessed for neuroma and postsurgical scarring (yes/no). Responders and non-responders were assigned following anesthetic injection of the IPBSN. The type of procedure (neurectomy/interventional pain procedure/other than nerve-associated therapy) and pain score at initial follow-up were recorded and patients were assigned as positive (full pain relief) or negative (partial/no pain relief) to therapeutic nerve treatment. Factors associated with a relevant visual analog scale (VAS) reduction were assessed using uni- and multivariate logistic regression models and chi-square for quantitative and qualitative variables (p ≤ 0.05). RESULTS: Responders (37/55) more often had an entrapment or an evident neuroma of the IPBSN (97% vs. 6%). A positive Hoffmann-Tinel sign (p = 0.002) and the absence of knee joint instability (p = 0.029) predicted a positive response of the diagnostic nerve block (90%; 26/29). In the follow-up after therapeutic nerve treatment, all patients with full pain relief showed neuromas or entrapment of the IPBSN. Patients negatively responding to therapeutic nerve treatment more frequently showed an additional knee joint instability (25% vs. 4%). CONCLUSION: Selective denervation for neuropathic knee pain is beneficial in selected patients with significant VAS reduction after diagnostic nerve block. Non-responders following diagnostic nerve block but sonographic evidence of IPBSN pathologies need to be evaluated for other causes such as knee joint instability. KEY POINTS: • Sonographic diagnosis of neuroma or entrapment of the IPBSN is frequently seen in patients with anteromedial knee pain and leads to a good response to diagnostic nerve block following knee surgery. • The vast majority of patients with clinical signs of IPBSN neuropathy and response to a diagnostic nerve block sustained full pain relief following therapeutic nerve treatment. • Patients not responding to therapeutic IPBSN treatment have to be evaluated for other causes of anteromedial knee pain such as knee joint instability.

Osteoarthritic and non-osteoarthritic patients show comparable coronal knee joint line orientations in a cross-sectional study based on 3D reconstructed CT images.

PURPOSE: Recently introduced total knee arthroplasty (TKA) alignment strategies aim to restore the pre-arthritic alignment of an individual patient. The native alignment of a patient can only be restored with detailed knowledge about the native and osteoarthritic alignment as well as differences between them. The first aim of this study was to assess the alignment of a large series of osteoarthritic (OA) knees and investigate whether femoral and tibial joint lines vary within patients with the same overall lower limb alignment. The secondary aim was to compare the alignment of OA patients to the previously published data of non-OA patients. This information could be useful for surgeons considering implementing one of the new alignment concepts. MATERIAL: Coronal alignment parameters of 2692 knee OA patients were measured based on 3D reconstructed CT data using a validated planning software (Knee-PLAN®, Symbios, Yverdon les Bains, Switzerland). Based on these measurements, patients' coronal alignment was phenotyped according to the functional knee phenotype concept. These phenotypes represent an alignment variation of either the overall alignment, the femoral joint line orientation or the tibial joint line orientation. Each phenotype is defined by a specific mean and covers a range of ± 1.5° from this mean. Mean values and distribution among the phenotypes are presented and compared between two populations (OA patients of this study and non-OA patients of a previously published study) as well as between HKA subgroups (varus, valgus and neutral) using t tests and Chi-square tests (p < 0.05). RESULTS: Femoral and tibial joint lines varied within patients with the same overall lower limb alignment. A total of 162 functional knee phenotypes were found (119 males, 136 females and 94 mutual phenotypes). Mean values differed between the OA and non-OA population, but differences were small (< 2°) except for the overall alignment (e.g. HKA). The distribution of OA and non-OA patients among the phenotypes differed significantly, especially among the limb phenotypes. CONCLUSION: Differences between OA and non-OA knees are small regarding coronal femoral and tibial joint line orientation. Femoral and tibial joint line orientation of osteoarthritic patients can, therefore, be used to estimate their native coronal alignment and plan an individualized knee alignment. LEVEL OF CLINICAL EVIDENCE: III.

Correlations of typical pain patterns with SPECT/CT findings in unhappy patients after total knee arthroplasty.

PURPOSE: The diagnostic process in patients after painful total knee arthroplasty (TKA) is challenging. The more clinical and radiological information about a patient with pain after TKA is included in the assessment, the more reliable and sustainable the advice regarding TKA revision can be. The primary aim was to investigate the position of TKA components and evaluate bone tracer uptake (BTU) using pre-revision SPECT/CT and correlate these findings with previously published pain patterns in painful patients after TKA. METHODS: A prospectively collected cohort of 83 painful primary TKA patients was retrospectively evaluated. All patients followed a standardized diagnostic algorithm including 99m-Tc-HDP-SPECT/CT, which led to a diagnosis indicating revision surgery. Pain character, location, dynamics and radiation were systematically assessed as well as TKA component position in 3D-CT. BTU was anatomically localized and quantified using a validated localization scheme. Component positioning and BTU were correlated with pain characteristics using non-parametric Spearman correlations (p < 0.05). RESULTS: Based on Spearman's rho, significant correlations were found between pain and patients characteristics and SPECT/CT findings resulting in nine specific patterns. The most outstanding ones include: Pattern 1: More flexion in the femoral component correlated with tender/splitting pain and patella-related pathologies. Pattern 3: More varus in the femoral component correlated with dull/heavy and tingling/stinging pain during descending stairs, unloading and long sitting in patients with high BMI and unresurfaced patella. Pattern 6: More posterior slope in the tibial component correlated with constant pain. CONCLUSION: The results of this study help to place component positioning in the overall context of the "painful knee arthroplasty" including specific pain patterns. The findings further differentiate the clinical picture of a painful TKA. Knowing these patterns enables a prediction of the cause of the pain to be made as early as possible in the diagnostic process before the state of pain becomes chronic. LEVEL OF EVIDENCE: Level III.

High inter- and intraindividual differences in medial and lateral posterior tibial slope are not reproduced accurately by conventional TKA alignment techniques.

PURPOSE: The purpose of this study was to describe the medial and lateral posterior tibial slope (MPTS and LPTS) on 3D-CT in a Caucasian population without osteoarthritis. It was hypothesised that standard TKA alignment techniques would not reproduce the anatomy in a high percentage of native knees. METHODS: CT scans of 301 knees [male:female = 192:109; mean age 30.1 ([Formula: see text] 6.1)] were analysed retrospectively. Tibial slope was measured medially and laterally in relation to the mechanical axis of the tibia. The proportion of MPTS and LPTS was calculated, corresponding to the "standard PTS" of 3°-7°. The proportion of knees accurately reproduced with the recommended PTS of 0°-3° for PS and 5°-7° for CR TKA were evaluated. RESULTS: Interindividual mean values of MPTS and LPTS did not differ significantly (mean (range); MPTS: 7.2° ( - 1.0°-19.0°) vs. LPTS: 7.2° ( - 2.4°-17.8°), n.s.). The mean absolute intraindividual difference was 2.9° (0.0°-10.8°). In 40.5% the intraindividual difference between MPTS and LPTS was > 3°. When the standard slope of 3°-7° medial and lateral was considered, only 15% of the knees were covered. The tibial cut for a PS TKA or a CR TKA changes the combined PTS (MPTS + LPTS) in 99.3% and 95.3% of cases, respectively. CONCLUSION: A high interindividual range of MPTS and LPTS as well as considerable intraindividual differences were shown. When implementing the recommended slope values for PS and CR prostheses, changes in native slope must be accepted. Further research is needed to evaluate the impact of altering a patient's native slope on the clinical outcome. LEVEL OF EVIDENCE: IV.

Detailed information gain and therapeutic impact of whole body computed tomography supplementary to conventional radiological diagnostics in blunt trauma emergency treatment: a consecutive trauma centre evaluation.

PURPOSE: The indication of whole body computed tomography (WBCT) in the emergency treatment of trauma is still under debate. We were interested in the detailed information gain obtained from WBCT following standardized conventional imaging (CI). METHODS: Prospective study including all emergency trauma centre patients examined by CI (focused assessment of sonography in trauma, chest and pelvic X-ray) followed by WBCT from 2011 to 2017. Radiology reports were compared per patient for defined body regions for number and severity of injuries (Abbreviated Injury Scale, AIS; Injury Severity Score, ISS), incidental findings and treatment consequences (Wilcoxon signed rank test, Spearman rho, Chi-square). RESULTS: 1271 trauma patients (ISS 11.3) were included in this study. WBCT detected more injury findings than CI in the equivalent body regions (1.8 vs. 0.6; p < 0.001). In 44.4% of cases at least one finding was missed by CI alone. Compared to WBCT, injury severity of specified body regions was underestimated by CI on average by an AIS of 1.9 (p < 0.001). In 22.0% of cases injury severity increased by an AIS ≥ 2 following WBCT. In 16.8% of patients additional injury findings resulted in a change of treatment (number needed to profit, NNP = 6 patients): NNP decreased from 25 for patients with an ISS < 7 up to nearly 2 for patients with an ISS > 25 at final evaluation, thereby demonstrating a significant improvement in the NNP with increasing ISS (rho = 0.33, p < 0.001). Moreover, WBCT in 88.4% of patients identified ≥ 1 incidental finding (mean 3.4) vs. 28.9% by CI only (p < 0.001). Overall, WBCT had treatment consequences in 31.9% of cases (NNP = 3.1). CONCLUSIONS: The application of WBCT in addition to CI in the emergency treatment of trauma had therapy consequences for almost every third patient. On the other hand, WBCT appeared not to be indicated (ISS < 8) in at least 2/5 of patients.

Typical Pain Patterns in Unhappy Patients After Total Knee Arthroplasty.

BACKGROUND: The primary aim of this study is to assess characteristics of pain in patients with ongoing pain after total knee arthroplasty (TKA). The secondary aim of this study is to identify specific pain patterns and link these to underlying pathologies. METHODS: A prospectively collected cohort of 97 painful primary TKA patients was retrospectively evaluated. All patients followed a standardized diagnostic algorithm, which led to a diagnosis that set the indication for revision surgery. Character, location, dynamics, and radiation of pain were systematically assessed and correlated with the underlying pathologies. RESULTS: Most frequent pain characters were pricking/lancinating (45.7%), pinching/crushing, and dull/heavy (38.6%); 89.5% of all patients localized their knee pain anteriorly; 48.1% reported pain aggravations by descending stairs. Radiating pain was reported in 14% of the patients. Patella-related problems (56.7%) and instability (52.6%) were the most frequent pathologies. Based on correlations between the characteristics 6 specific pain patterns were identified. The most outstanding ones include the following: pattern 1, instability is associated with jumping/shooting, pricking/lancinating and tugging/wrenching pain, and aggravated by chair raising and starting; pattern 6, pain aggravation by descending stairs is associated with anterior and lateral jumping/shooting, tingling/stinging and sharp/lacerating pain character, and TKA positioning and patella baja. CONCLUSION: The assessment of painful TKA patients involving specific pain patterns help to further differentiate and define the clinical picture and ultimately the cause of a painful TKA. If the causes of the described complaints are known, a decision for a therapy can be made reliably and sustainably at an early stage before the state of pain becomes chronic.

Reasons for failure in primary total knee arthroplasty - An analysis of prospectively collected registry data.

OBJECTIVE: The aim of this study was to determine the causes leading to a first revision of primary total knee arthroplasty (TKA) in a specialized knee centre and compare the results with previously published data. METHODS: Prospectively collected data of a consecutive number of 195 patients after primary TKA and who underwent first revision surgery after completing the diagnostic algorithm for persistent knee pain were included. Data was prospectively collected from a specialized knee centre in which the patients presented between 2015 and 2020 and retrospectively analysed. Indications for revision surgery were categorized using all available information from patients' records. Patients were divided into early (up to two years) and late revision (more than two years). RESULTS: Overall mean time from index to revision surgery was 3.6 years. 49% of knee revisions occurred in the first two years, 51% after two years. 86% of the patients were referred to the knee centre from other surgeons. The most frequent reason for revision was instability, followed by patellofemoral problems, extensor mechanism insufficiency and malalignment. The most frequently performed revision was complete removal and re-implantation of a semi constrained implant design (52.5%) followed by revision using a full constrained implant design (16%). Secondary patella-resurfacing as part of complete revision was carried out in 71.5% of the cases. The majority of the patients showed concurrent reasons for TKA failure with significant correlations amongst another. Furthermore, correlations were identified between indications for revision surgery and revision implant designs. CONCLUSION: In a specialized knee centre the most common indications for the first TKA revision were instability and patellofemoral and/or extensor mechanism insufficiency followed by malalignment. In most patients there was not only one failure mode, but a combination of many. It is important to establish a standardized diagnostic algorithm to facilitate comprehensive and efficient diagnostics and the optimal treatment.

Short-term outcome following significant trauma: increasing age per se has only a relatively low impact.

PURPOSE: Ongoing demographic changes go hand in hand with an increasing number of elderly injured. Given the conflicting literature we wanted to know how much age per se, apart from other factors, actually explains the outcome for elderly trauma patients. METHODS: Retrospective analysis of prospectively collected data on all significantly injured (new injury severity score, NISS ≥ 8) adult patients treated at a Swiss trauma center between 01.01.2010 and 31.12.2017. The association of age and other demographic, trauma or treatment-related variables on parameters of short-term outcome was examined using uni- and multivariate analyses (mean ± SD; R2; p < 0.05). RESULTS: 2692 consecutive patients (33.4% female; mean age 58.1 ± 21.7; hospital mortality 10.1%) were studied. Detailed analysis of quinquennial age groups demonstrated a significant decline in outcome with regard to mortality or return-to-home rate following hospital discharge after the age of 60 years (p < 0.001). In univariate analysis, age explained 4.6% and the number of years ≥ 60 5.9% of hospital mortality. In multivariate analysis, the investigated demographic, trauma or treatment-related parameters contributed at 36.5% to prediction of mortality, age added another 1.5% and number of years ≥ 60 another 2.1% (R2). CONCLUSION: This monocenter evaluation showed a significant decline in short-term outcome and an increase in hospital resource requirements by the trauma patients investigated after the age of 60 years. Even so, after controlling for demographic, injury and treatment variables, age per se only added less than 2% to the prediction of hospital mortality.

MR variability of collagen meniscal implant remodelling in patients with good clinical outcome.

PURPOSE: Collagen meniscal implants (CMI) have variable imaging findings on MRI and it remains ambiguous, if alterations may be present in asymptomatic patients. The aim was, to evaluate MR morphological characteristics and volume of CMI in the early, mid- and long-term follow-up. METHODS: Fifty-seven patients (mean age, 43.6±11 years; 41 male/16 female) with good clinical outcome (subjective visual analogue scale for satisfaction < 2 and a Lysholm-score ≥ 84) after CMI were assessed retrospectively using MRI 1, 2 and 3-8 years postoperatively. CMI morphology, signal intensity (SI), homogeneity and size were assessed and a meniscal score was calculated. Chondral defects and bone marrow edema pattern were reported and summarized in a chondral score. Meniscal extrusion and volume were evaluated. Intra- and inter-reader reliabilities were calculated. Spearman and partial correlations were used (p < 0.05). RESULTS: One year postoperatively, the CMI varied in size [10% (4/40) normal, 30% (12/40) small, 60% (24/40) hypertrophic] and was hyperintense and inhomogeneous in all patients. At long-term follow-up, the size of CMI decreased [6% (1/17) resorbed, 18% (3/17) normal, 41% (7/17) small, 35% (6/17) hypertrophic]. The SI of the CMI changed to normal in only 13% (2/16). The majority was still hyperintense [87% (14/16)]. Less meniscal extrusion was present in the follow-up [71% (11/16) versus initially 93% (37/40)]. The meniscal score improved significantly (ρ = 0.28). Over time, full-thickness femoral chondral defects were increasingly present [65% (10/17) versus initially 33% (13/40)] and the chondral score worsened significantly (p = 0.017). CONCLUSION: Abnormal and inhomogeneous SI and irregular margins of the early postoperative CMI on MRI are findings seen in patients with good clinical results and should not necessarily be overcalled when reporting MRI. These features tend to decrease over time. LEVEL OF EVIDENCE: IV.

Osteoarthritic knees have a highly variable patellofemoral alignment: a systematic review.

PURPOSE: This systematic review aimed to evaluate the variability of patellofemoral (PF) alignment and trochlear morphology in osteoarthritic knees. METHODS: PF alignment of the knee was defined by the following parameters: the sulcus angle (SA), femoral trochlear depth (FTD), patellar tilt angle (PTA), lateral patellofemoral angle (LPFA), lateral femoral trochlear inclination (LFTI) and tibial tubercle-trochlear groove distance (TT-TG). The electronic databases MEDLINE and EMBASE were searched from database inception to the search date (February 19, 2019) and were screened for relevant studies. The PRISMA guidelines were followed. Articles reporting PF alignment measurements of osteoarthritic knees in patients over 40 years old were included. Data were extracted and methodological quality was assessed using a 14-item checklist. RESULTS: A total of 8 studies met the inclusion criteria. The studies reported mean values ± SD between 120° and 141.1° ± 7.7 for the SA; 5.8 mm ± 1.4 for the FTD; between - 0.1° ± 3.3 and 10.3° ± 5.7 for the PTA; between 5.8° ± 5.4 and 17° for the LPFA; between 23.2° ± 5.0 and 27.1° ± 4.4 for the LFTI; and 5.8 mm ± 5.4 for the TT-TG. CONCLUSION: PF alignment in the osteoarthritic knee is more variable than expected. This finding should encourage surgeons to consider the individual preoperative PF alignment more precisely with the aim of reducing anterior knee pain (AKP) after TKA. 3D-CT imaging might be of great value to analyse the PF alignment in an appropriate way. LEVEL OF EVIDENCE: Level III.

Comparative analysis of MGAP, GAP, and RISC2 as predictors of patient outcome and emergency interventional need in emergency room treatment of the injured.

PURPOSE: Little is known about the capabilities of triage and risk scores to predict the outcomes of injured patients, other than mortality, or to determine the need for trauma center resources. METHODS: Retrospective analysis of prospectively gathered monocenter data on consecutively admitted adult emergency room trauma patients. For each patient, the GAP (Glasgow Coma Scale, Age and Pressure), MGAP (mechanism + GAP) scores and the revised injury severity classification 2 (RISC2) were calculated. The predictive performance of these scores was compared for the assessment of trauma severity, hospital resource need and early patient outcomes (area under the receiver operator characteristics, AUROC). RESULTS: 2112 patients were evaluated [mean age 49.1 years; Injury Severity Score (ISS) 9.5]. GAP, MGAP, and RISC2 worked best at predicting mortality (AUROC 93.2, 93.5 and 96.1%, respectively). Other endpoints such as ISS > 15, emergency interventions, disability status, and return-not-home were predicted less precisely by these three scores, better by RISC2 (AUROC range 66.2-88.8%) than by (M)GAP-scores (55.2-84.1%), except for preclinical interventions. Over- and undertriage rates for the (M)GAP scores varied between 27.5-53.4% and 10.4-30%, respectively. CONCLUSION: The almost comparable precision of the three risk scores in the prediction of outcome or interventional need following trauma, and the fact, that the RISC2 can only be calculated following extensive diagnostics, favor earlier applicable (M)GAP scoring in the emergency setting. Overall, due to its easier use, the GAP appears to be the most preferable for the early assessment and triage of the injured in a trauma setting based on this European trauma center experience (NCT02165137).

[How often is a chest tube needed following thoracic trauma in the severely injured-and when is more needed? : Data from a Swiss trauma center for planning of resources and surgical training]. / Wie oft braucht es eine Thoraxdrainageneinlage beim Thoraxtrauma des schwerer Verletzten ­ und wann mehr? : Grundlagen eines Schweizer Traumazentrums zur Planung von Ressourcen und Ausbildungskapazitäten.

BACKGROUND AND OBJECTIVE: With respect to the resource and training requirements of a Swiss trauma center, we wanted to know how frequently relevant thoracic injuries occur and how often specialized thoracic surgery is needed. MATERIAL AND METHODS: Retrospective analysis of all severely injured patients with a new injury severity score (NISS) ≥8 from 2010-2017 with respect to relevant thoracic injuries (abbreviated injury scale, AIS thorax without thoracic vertebral injuries ≥2). RESULTS: In the 7­year observational period 2839 patients with NISS ≥8 were treated as an emergency. Of these 791 (27.9%) suffered a relevant injury in the thoracic region and 27.1% (n = 215) of them required a thoracic intervention, which in 86.5% (n = 186) corresponded to a thoracic drainage only and in 13.5% (n = 29) to an extended intervention. In 19 cases following relevant thoracic injury, a thoracic surgeon was also required, 4 times immediately and 4 times within 24 h of hospital arrival. On average, 30 emergency thoracic drainage insertions per year corresponded to 1-2 interventions per surgeon in training. CONCLUSION: In the observational period only 1% of all relevant thoracic injuries required emergency thoracic surgical care beyond a pleural drainage. Given this low rate, for efficiency and cost reasons a thoracic surgery on-call service appears to be appropriate and compulsory attendance is not needed; however, the capability to insert a thoracic drainage must be appropriately assured by surgical training. In view of the number of cases observed per trainee, the minimum number of interventions required according to specialty training regulations should be well achievable.

Pain in the aftermath of minimal invasive treatment for unilateral incompetence of the great saphenous vein.

OBJECTIVES: Assessment of postprocedural pain after minimal invasive treatment of unilateral incompetence of the great saphenous vein. METHODS: A total of 85 patients treated with endovenous laser ablation (1470 nm) in combination with foam sclerotherapy and evulsions reported postprocedural pain on a visual analogue scale (0-10) during 28 days after treatment. RESULTS: A mean pain reduction from 3.9 on the first postinterventional day to 0.3 was noted during the observation time. After 28 days, 7% of patients had a visual analogue scale >1. Higher body mass index was strongly associated with more pain during the whole follow-up period (p < 0.01). Higher energy application per cm vein and greater great saphenous vein diameter showed more pain in the first week. Other factors like clinical stage CEAP classification, combination of laser with avulsions and/or sclerotherapy, season of treatment timepoint, and age or sex did not influence postinterventional pain course. CONCLUSION: Higher body mass index and higher energy application per cm are associated with more postprocedural pain after endovenous laser ablation.

Increased focal bone tracer uptake at the popliteus muscle origin in primary TKA compared with revision TKA.

OBJECTIVE: The purpose of the study was to investigate if the TKA design (cruciate retaining (CR), posterior stabilized (PS), revision prostheses) had an influence on the bone tracer uptake (BTU) pattern at the origin of the popliteus muscle. MATERIALS AND METHODS: A total of 92 knees (male:female = 46:46) which had undergone prior TKA were included in this retrospective study, comprising the following 3 groups: (i) CR primary TKA (n = 45); (ii) PS primary TKA (n = 24); (iii) revision TKA (n = 23). All patients received a SPECT/CT after TKA surgery. SPECT/CT images were reviewed for the presence of BTU in the lateral femoral condyle (origin of the popliteus muscle) by two observers using Syngo.via software (Siemens Healthcare, Erlangen, Germany). The observers recorded the BTU pattern qualitatively in the lateral femoral condyle as either (i) absent; (ii) present and diffuse; and (iii) present and focal in the region of the popliteus muscle origin. RESULTS: In patients with a CR and PS design, focal increased BTU at the origin of the popliteus muscle was found in 80.0% and 83.3% respectively. Diffuse BTU was the predominant finding in patients with revision TKA (60.9%). The patterns of BTU did not show significant differences between the CR and the PS design. However, patterns of BTU differed significantly between primary TKA designs and revision TKA (p < 0.001). CONCLUSION: Differences in patterns of BTU at the popliteus muscle origin between primary TKA and revision prosthesis may be the result of decreased insertional tensile forces of the popliteus muscle after revision surgery due to increased stability provided by the revision design.

Trauma center need: the American College of Surgeons' definition in contrast to Swiss highly specialized medicine regulations-a Swiss trauma center perspective.

PURPOSE: According to the American College of Surgeons (ACS) recommendations, the benchmark for trauma center need (TCN) is an Injury Severity Score (ISS) > 15. In contrast, Swiss highly specialized medicine (HSM) regulations set out TCN for all patients with an ISS > 19 or an Abbreviated Injury Severity (AIS) of the head ≥ 3. This investigation assessed to what extent the modification might be justified. METHODS: Consecutive analysis of all significantly injured (new ISS, NISS ≥ 8) adults treated in a trauma center from 2010 to 2016 based on their ISS and AIS head and in respect to utilized resources and outcome. RESULTS: Of 2171 patients (mean age 57.2 ± 21.6; ISS 15.0 ± 8.5) 40.1% fulfilled the ACS and 52.7% the HSM-definition of TCN. Comparative analysis of specified subgroups representing combinations of the ISS and the AIS head revealed that patients within the HSM but not within the ACS-definition of TCN achieved worse outcomes in mortality or on the Glasgow Outcome Score and had a higher inpatient rehabilitation rate than patients with an ISS < 15 and an AIS head < 3 compared to patients with an ISS > 15. Mortality for patients with an ISS 16-19 and AIS head < 3 (qualifying for the ACS but not the HSM-definition of TCN) was found to be twice as high for patients who were not in the ACS or the HSM group (ISS < 16 & AIS head < 3). CONCLUSIONS: If confirmed by others, both the ACS and the Swiss-recommendations for TCN should be adapted accordingly, provided that the resultant increased workload is feasible for the trauma centers concerned.