Aims

The paediatric trigger thumb is a distinct clinical entity with unique anatomical abnormalities. The aim of this study was to present the long-term outcomes of A1 pulley release in idiopathic paediatric trigger thumbs based on established patient-reported outcome measures.

Aims

The development of lumbar lordosis has been traditionally examined using angular measurements of the spine to reflect its shape. While studies agree regarding the increase in the angles during growth, the growth rate is understudied, and sexual dimorphism is debated. In this study, we used a novel method to estimate the shape of the lumbar curve (LC) using the landmark-based geometric morphometric method to explore changes in LC during growth, examine the effect of size and sex on LC shape, and examine the associations between angular measurements and shape.

This study compared the pullout forces of the initial implantation and the “cement-in-cement” revision technique for short and standard-length (125 mm vs. 150 mm) Exeter. ®. V40 femoral stems used in total hip arthroplasty (THA). The idea that the pullout force for a double taper slip stem is relative to the force applied to the femur and that “cement-in-cement” revision provides the same reproduction of force. A total sample size of 15 femoral stems were tested (Short, n = 6 and Standard, n = 9). 3D printed fixtures for repeatable sample preparation were used to minimize variance during testing. To promote stem subsidence and to simulate an in vivo environment, the samples were placed in an incubator at 37°C at 100% humidity and experienced a constant compressive loading of 1335 N for 14 days. The samples underwent a displacement-controlled pullout test. After the initial pullout test, “cement-in-cement” revision will be performed and tested similar to the initial implantation to observe the efficacy of the revision technique. To compare the pullout forces between the two groups, a Kruskal-Wallis test using a significance level of 0.05 was conducted. The mean maximum pullout force for the short and standard-length femoral stems were 3939 ± 1178 N and 5078 ± 1168 N, respectively. The Kruskal-Wallis test determined no statistically significant difference between the two groups for the initial implantation (p = 0.13). The “cement-in-cement” revision pullout force will be conducted in future testing. This study demonstrated the potential use of short stem designs for THA as it provides similar levels of fixation as the standard-length femoral stem. The potential benefits for using a short stem design would be providing similar load transfer to the proximal femur, preserving proximal metaphyseal femoral bone in primary replacement, and reducing the invasiveness during revision

For all the research into arthroplasty, provision of total knee arthroplasty (TKR) services based on gender in the Australian context is yet to be explored. International literature points toward a heavily gender biased provision of TKA services, skewed away from female patients. This research has aimed to assess the current experience of Australian female patients and to explore better assessment techniques that could provide more equitable services. A retrospective cohort analysis has been conducted using pre-op PROMs data, where available, from the Australian National Joint Replacement Registry (AOANJRR), between 7 August 2018 and 31 December 2021, including: EQ VAS Health; Oxford Knee Score; joint pain; and KOOS-12. Data was adjusted for age, ASA score, BMI, primary diagnosis, public vs private hospital, surgeon gender and years of practice (as estimated from years of registry data available). Of 1,001,231 procedures performed, 27,431 were able to be analysed (12,300 male and 15,131 female). Gender-based bias against female patients reached statistical significance across all PROM scores, according to the Kruskal-Wallis test of difference (p-value <0.0001). Males were more likely to undergo TKR than females, with odds ratios remaining statistically significant when adjusted for age, ASA score, BMI, primary diagnosis, and hospital type. Numbers were further analysed for surgeon years of recorded practice and surgeon gender with mixed results. This study found that women were less likely to undergo TKR despite worse scores on every pre-op PROM available, thus we demonstrate a statistically significant gender-based bias against female patients. More effort needs to be made to identify the base of this bias and find new ways to assess patients that can provide more equitable provision of healthcare

Aim. In Two-Stage Revision, utilizing temporary antibiotic spacers is widely accepted. These spacers are available prefabricated or can be individually moulded intraoperatively. In this study, we analysed the efficacy of prefabricated and individual spacers in infection eradication of periprosthetic joint infection in knee and hip arthroplasties. Method. All spacers implanted at a tertiary academic center during two-stage exchanges between June 2010 and December 2019 were retrospectively analysed. Among 249 patients, 167 cases (minimum follow-up ≥ 12 months) were included. Commercial spacers contained vancomycin and gentamycin, while individual spacers contained vancomycin alone. Subgroup analysis by manufacturers was conducted using non-parametric methods including Mann-Whitney U and Kruskal-Wallis tests. Survival analysis utilized Kaplan-Meier curves, and categorical data were analyzed using the Chi² test. Statistical significance was defined as p < 0.05. Results. Of the 167 patients included, a prefabricated spacer was implanted in 105 cases (62.9%) and an individual spacer was implanted in 62 cases (37.1%). In 106 cases, infection healing according to the Delphi consensus was achieved with a mean follow-up of 37.8 months [12;99]. Infection persistence was seen in 31.4% of the preformed spacers and in 45.2% of the individual spacers, with no statistically significant difference (p = 0.09). (Results are shown in the illustration). In the multivariate analysis, preoperative anemia (p = 0.02 OR 2.25 CI-95% 1.2-4.4 p = 0.01) and diagnosed paraneoplastic disease (p = 0.01 OR 3.0 CI-95% 1.4-6.7 p = 0.01) were found to be risk factors for failure. Conclusions. Two-stage Revisions are successfully suitable options for the treatment of PJI. In this study, infection eradication was independent of the type of spacer. Anemia and paraneoplastic diseases were found to be risk factors of failure

Abstract. OBJECTIVES. To determine if force measured using a strain gauge in circular external fixation frames is different for 1) different simulated stages of bone healing, and for 2) fractures clinically deemed either united or un-united. METHODS. In a laboratory study, 3 similar Ilizarov frame constructs were assembled using a Perspex bone analogue. Constructs were tested in 10 different clinical situations simulating different stages of bone healing including with the bone analogue intact, with 1,3 and 50mm gaps, and with 6 materials of varying stiffness's within the 50mm gap. A Bluetooth strain gauge was inserted across the simulated fracture focus, replacing one of the 4 threaded rods used to construct the frame. Constructs were loaded to 700N using an Instron testing machine and maximum force during loading was measured by the strain gauge. Testing was repeated with the strain gauge replacing each of the 4 threaded rods in turn, with measurements being repeated 3 times, across all 3 frame constructs for all 10 simulated clinical situations (n=360). Force measurements between the situations were compared using a Kruskal-Wallis test (KW) and a post-hoc Steel test was used for multiple comparison against control (intact bone model). Additionally, a pilot study has been initiated to assess clinical efficacy of the strain gauge measurement in patients with circular frames. The strain gauge replaced the anterior rod across the fracture focus for each patient. Patients were asked to step on a weighing scale with their affected limb, and maximum weight transfer through the limb and maximal force measured in the frame were recorded. This was repeated 3 times and a mean ratio of force to weight through affected limb was calculated for each patient. The clinical situation at each measurement was designated as united or un-united by one of the senior authors for analysis. Force measurements between the situations were compared using a Wilcoxon-Mann-Whitney test. RESULTS. In the laboratory study, including all constructs with the strain gauge in all positions, a statistically significant relationship between model stability and force measured was identified (KW test for overall relationship p<0.0001). The largest force was measured in the model with a 50mm gap (median 170N, IQR 155–192, range 83–213) and the smallest in the intact bone model (median 3N, IQR 1–8, range 0–11). Multiple comparison testing found a significant difference between intact bone and all the unstable situations (p=0.002 or better). Examining initial results from our pilot clinical study, nine measurements were available in seven patients. Three of these were taken in patients with fractures yet to unite, six in patients where union has since been confirmed clinically. The median force measured was significantly greater where the fracture was not united (median 1.66 N/kg, range 1.07–1.99 vs 0.12 N/kg, range 0.05–0.73, p=0.02). CONCLUSIONS. This laboratory study demonstrates that force measurement may be different at different stages of healing, and although only limited data was available, a pilot clinical study showed a significant relationship between the force measured and clinical union of the patient's fracture. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Aims. The aim of this retrospective study was to determine if there are differences in short-term clinical outcomes among four different types of matrix-associated autologous chondrocyte transplantation (MACT). Methods. A total of 88 patients (mean age 34 years (SD 10.03), mean BMI 25 kg/m. 2. (SD 3.51)) with full-thickness chondral lesions of the tibiofemoral joint who underwent MACT were included in this study. Clinical examinations were performed preoperatively and 24 months after transplantation. Clinical outcomes were evaluated using the International Knee Documentation Committee (IKDC) Subjective Knee Form, the Brittberg score, the Tegner Activity Scale, and the visual analogue scale (VAS) for pain. The Kruskal-Wallis test by ranks was used to compare the clinical scores of the different transplant types. Results. The mean defect size of the tibiofemoral joint compartment was 4.28 cm. 2. (SD 1.70). In total, 11 patients (12.6%) underwent transplantation with Chondro-Gide (matrix-associated autologous chondrocyte implantation (MACI)), 40 patients (46.0%) with Hyalograft C (HYAFF), 21 patients (24.1%) with Cartilage Regeneration System (CaReS), and 15 patients (17.2%) with NOVOCART 3D. The mean IKDC Subjective Knee Form score improved from 35.71 (SD 6.44) preoperatively to 75.26 (SD 18.36) after 24 months postoperatively in the Hyalograft group, from 35.94 (SD 10.29) to 71.57 (SD 16.31) in the Chondro-Gide (MACI) group, from 37.06 (SD 5.42) to 71.49 (SD 6.76) in the NOVOCART 3D group, and from 45.05 (SD 15.83) to 70.33 (SD 19.65) in the CaReS group. Similar improvements were observed in the VAS and Brittberg scores. Conclusion. Two years postoperatively, there were no significant differences in terms of outcomes. Our data demonstrated that MACT, regardless of the implants used, resulted in good clinical improvement two years after transplantation for localized tibiofemoral defects. Cite this article: Bone Joint Res 2021;10(7):370–379

Aims. The adequate provision of personal protective equipment (PPE) for healthcare workers has come under considerable scrutiny during the COVID-19 pandemic. This study aimed to evaluate staff awareness of PPE guidance, perceptions of PPE measures, and concerns regarding PPE use while caring for COVID-19 patients. In addition, responses of doctors, nurses, and other healthcare professionals (OHCPs) were compared. Methods. The inclusion criteria were all staff working in clinical areas of the hospital. Staff were invited to take part using a link to an online questionnaire advertised by email, posters displayed in clinical areas, and social media. Questions grouped into the three key themes - staff awareness, perceptions, and concerns - were answered using a five-point Likert scale. The Kruskal-Wallis test was used to compare results across all three groups of staff. Results. Overall, 315 staff took part in our study. There was a high awareness of PPE guidance at 84.4%, but only 52.4% of staff reported adequate PPE provision. 67.9% were still keen to come to work, despite very high levels of anxiety relating to contracting COVID-19 despite wearing PPE. Doctors had significantly higher ratings for questions relating to PPE awareness compared to other staff groups, while nursing staff and OHCPs had significantly higher levels of anxiety compared to doctors in relation to PPE and contracting COVID-19 (p < 0.05 using a Kruskal-Wallis test). Conclusion. We believe four recommendations are key to improve PPE measures and decrease anxiety: 1) nominated ward/department PPE champions; 2) anonymized reporting for PPE concerns; 3) formal PPE education sessions; and 4) drop-in counselling sessions for staff. We hope the insight and recommendations from this study can improve the PPE situation and maintain the health and wellbeing of the clinical work force, in order to care for COVID-19 patients safely and effectively

A growing number of recent investigations on the human genome, gut microbiome, and proteomics suggests that the loss of mucosal barrier function, particularly in the gastrointestinal tract, may substantially affect antigen trafficking, ultimately influencing the close bidirectional interaction between the gut microbiome and the immune system. This cross-talk is highly influential in shaping the host immune system and ultimately clinical infections. The hypothesis of the current study was that a change in microbiome and/or breach in GI epithelial barrier could be partially responsible for development of periprosthetic joint infections (PJI). Multiple biomarkers of gut barrier disruption were tested in parallel in plasma samples collected as part of a prospective cohort study of patients undergoing revision arthroplasty for aseptic failures or PJI (As defined by the 2018 ICM criteria). All blood samples were collected before any antibiotic was administered. Samples were tested for Zonulin, soluble CD14 (sCD14), and lipopolysaccharide (LPS) using commercially available enzyme-linked immunosorbent assays. Statistical analysis consisted of descriptive statistics, Mann-Whitney t-test, and Kruskal-Wallis test. A total of 134 patients were consented and included in the study. 44 were classified as PJI (30 chronic and 14 acute), and 90 as aseptic failures (26 primaries and 64 aseptic revisions). Both Zonulin and sCD14, but not LPS, were found to be significantly increased in the PJI group compared to non-infected cases (p<0.001; p=0.003). Higher levels of Zonulin were found in acute infections compared to chronic PJI (p=0.005. This prospective ongoing study reveals a possible link between gut permeability and the ‘gut-immune-joint axis’ in PJI. If this association continues to be born out with larger cohort recruitment and more in-depth analysis, it would have an immense implication in managing patients with PJI. In addition to administering antimicrobials, patients with PJI and other orthopedic infections may require gastrointestinal modulators such as pro and prebiotics

Aim. This study aims to define the normal postoperative presepsin kinetics in patients undergoing primary cementless total hip replacement (THR). Methods. Patients undergoing primary cementless THR at our Institute were recruited. At enrollment anthropometric data, smocking status, osteoarthritis stage according to Kellgren and. Lawrence, Harris Hip Score (HHS), drugs assumption and comorbidities were recorded. All the patients underwent serial blood tests, including complete blood count, presepsin (PS) and C-Reactive Protein (CRP) 24 hours before arthroplasty and at 24-, 48-, 72- and 96-hours postoperatively and at 3-, 6- and 12-months follow-up. Statistical analysis was performed with SPSS v25.0 (SPSS Inc, Chicago, IL, USA). The Wilcoxon and Kruskal-Wallis tests followed by the Dunn multiple comparison post hoc tests were carried out. Correlations between PS, CRP and TOT were assessed using the Spearman rank correlation coefficient. P values below 0.05 were considered significant. Results and conclusion. A total of 96 patients were recruited (51 female; 45 male; mean age= 65.74±5.58) were recruited. The mean PS values were: 137.54 pg/ml at baseline, 192.08 pg/ml at 24-hours post-op; 254.85 pg/ml at 48-hours post-op; 259 pg/ml at 72-hours post-op; 248.6 pg/ml at 96-hour post-op; 140.52 pg/ml at 3-months follow-up; 135.55 pg/ml at 6-months follow-up and 130.11 pg/ml at 12-months follow-up. In two patients (2.08%) a soft-tissue infection was observed; in these patients higher levels (>350pg/mL) were recorded at 3-months follow-up. The lack of a presepsin decrease at 96 hours post-operatively should be a predictive factor of infection

Abstract. Objectives. Oil-based fluids can be used to enhance the properties of polyethylene materials. For example, vitamin E infused polyethylene has a superior oxidation resistance and Lipiodol infused polyethylene has an enhanced X-ray attenuation. The aim of this study was to evaluate the long-term influence of oily fluid on the chemical, physical and tensile properties of polyethylene. Methods. An accelerated ageing procedure (an elevated temperature (80. °. C) for four weeks in air. 1. ) was used to investigate the oxidative stability (ASTM F2012-17). 2. , tensile (ISO 527). 3. and thermal properties. 4. of oil treated polyethylene (n=5, GUR 1050, Celanese, Germany)and compared with clinically used polyethylene controls (oil-free standard and thermally treated polyethylene). All the experiments were performed on aged and unaged specimens in accordance to international standards and compared to currently available literature. A Kruskal-Wallis test was performed using a custom MATLAB code (R2017a, USA); with p < 0.05 considered statistically significant. Results. Samples treated with an oil (Vitamin E or Lipiodol) had a higher oxidation stability than currently used medical grade polyethylene, indicated by a smaller increase in oxidation index after ageing (Vitamin E 36%, Lipiodol 40%, untreated 136 %, thermally treated 164%). The mechanical degradation of oil treated polyethylene was also less significant than the untreated controls, as all the tensile properties of oil treated polyethylene after ageing were significantly higher than the standard controls (p>0.05). There was also no alteration in the percentage crystallinity of oil treated samples after ageing. Conclusion. The result of this study indicate that the presence of an oily fluid in polyethylene does not reduce its oxidative stability or tensile properties, providing improved material properties for long term implant applications. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Frailty has been shown to be a risk predictor for peri-operative adverse events (AEs) in patients undergoing various type of spine surgery. However, its relationship with Patient Related Outcome Measures (PROMS) remains unknown. The primary objective of this study was to determine the impact of frailty on PROMS in patients undergoing surgery for thoraco-lumbar degenerative conditions. The secondary objective was to determine the association between frailty and baseline PROMS. This is a retrospective study of a prospective cohort of patients >55 years old who underwent surgery between 2012 and 2018. Patient data and PROMS (EQ-5D, SF-12, ODI, back and leg pain NRS) were extracted from the Canadian Spine Outcomes and Research Network registry for a single academic centre. Frailty was retrospectively calculated using the modified frailty index (mFI) and patient were classified as frail, pre-frail and non-frail. Patient characteristics and outcomes were analyzed using ANOVA or Kruskal-Wallis test for continuous variables and Chi square or Fisher's exact test for proportions. A generalized estimating equations (GEEs) regression model was used to assess the association between patients' baseline frailty status and PROMs measures at three and 12 months. 293 patients were included with a mean age of 67 ± 7 years. Twenty-two percent of the patients (n= 65) were frail, 59 % (n=172) were pre-frail and 19% (n=56) were non-frail. At baseline, the three groups had similar PROMS, except for the PCS which was worse in the frail group (mean difference [95% CI], −4.9 [−8.6;-1.1], p= 0.0083). The improvement in the EQ-5D, PCS, MCS, ODI, back and leg pain NRS scores was not significantly different between the three groups (p> 0.05). The was no difference in the evolution of the PROMS at three and 12 months between the three groups (p> 0.05). Although frailty is a known predictor of AEs, it does not predict worse PROMS after spine surgery in that population. At baseline, non-frail, pre-frail and frail patients have similar PROMS

Introduction and Objective. Anterior cruciate ligament reconstruction (ACLR) with tendon autografts is the “gold standard” technique for surgical treatment of ACL injuries. Common tendon graft choices include patellar tendon (PT), semitendinosus/gracilis “hamstring” tendon (HT), or quadriceps tendon (QT). Healing of the graft after ACLR may be affected by graft type since the tissue is subjected to mechanical stresses during post-operative rehabilitation that play important roles in graft integration, remodeling and maturation. Abnormal mechanical loading can result in high inflammatory and degradative processes and altered extracellular matrix (ECM) synthesis and remodeling, potentially modifying tissue structure, composition, and function. Because of the importance of load and ligamentization for tendon autografts, this study was designed to compare the differential inflammatory and degradative metabolic responses to loading by three tendon types commonly used for autograft ACL reconstruction. Materials and Methods. With IRB approval (IRB # 2009879) and informed patient consent, portions of 9 QT, 7 PT and 6 HT were recovered at the time of standard of care ACLR surgeries. Tissues were minced and digested in 0.2 mg/ml collagenase solution for two hours and were then cultured in 10% FBS at 5% CO. 2. , 37°C, and 95% humidity. Once confluent, cells were plated in Collagen Type I-coated BioFlex® plates (1 × 10. 5. cells/well) and cultured for 2 days prior to the application of strain. Then, media was changed to supplemented DMEM with 2% FBS for the application of strain. Fibroblasts were subjected to continuous mechanical stimulation (2-s strain and 10-s relaxation at a 0.5 Hz frequency) at three different elongation strains (mechanical stress deprivation-0%, physiologic strain-4%, and supraphysiological strain-10%). 9. for 6 days using the Flexcell FX-4000T strain system. Media was tested for inflammatory biomarkers (PGE2, IL-8, Gro-α, and MCP-1) and degradation biomarkers (GAG content, MMP-1, MMP-2, MMP-3, TIMP-1, and TIMP-2). Significant (p<0.05) difference between graft sources were assessed with Kruskal-Wallis test and post-hoc analysis. Results are reported as median± interquartile range (IQR). Results. Differences in Inflammation-Related Biomarker Production (Figure 1): The production of PGE2 was significantly lower by HT fibroblasts compared to both QT and PT fibroblasts at all timepoints and strain levels. The production of Gro-α was significantly lower by HT fibroblasts compared to QT at all time points and strain levels, and significantly lower than PT on day 3 at 0% strain, and all strain levels on day 6. The production of IL-8 by PT fibroblasts was significantly lower than QT and HT fibroblast on day 3 at 10% strain. Differences in Degradation-Related Biomarker Production (Figure 2): The production of GAG by HT fibroblasts was significantly higher compared to both QT and PT fibroblasts on day 6 at 0% strain. The production of MMP-1 by the QT fibroblasts was significantly higher compared to HT fibroblasts on day 3 of culture at all strain levels, and in the 0% and 10% strain levels on day 6 of culture. The production of MMP-1 by the QT fibroblasts was significantly higher compared to PT fibroblasts at in the 0% and 4% strain groups on day 3 of culture. The production of TIMP-1 by the HT fibroblasts was significantly lower compared to PT fibroblasts on day 3 of culture. Conclusions. The results of this study identify potentially clinically relevant difference in the metabolic responses of tendon graft fibroblasts to strain, suggesting a lower inflammatory response by hamstring tendon fibroblasts and higher degradative response by quadriceps tendon fibroblasts. These responses may influence ACL autograft healing as well as inflammatory mediators of pain in the knee after reconstruction, which may have implications regarding graft choice and design of postoperative rehabilitation protocols for optimizing outcomes for patients undergoing ACL reconstruction. For any figures or tables, please contact the authors directly

Introduction and Objective. In multiple trauma patients, as well as in the healing of isolated fractures (Fx) with heavy bleeding (trauma haemorrhage, TH), complications occur very often. This is particularly evident in elderly patients over 65 years of age. Since these accompanying circumstances strongly influence the clinical course of treatment, the influence of age on bone regeneration after femoral fracture and severe blood loss was investigated in this study. Materials and Methods. 12 young (17–26 weeks) and 12 old (64–72 weeks) male C57BL / 6J mice per group were examined. The fracture group Fx underwent an osteotomy after applying an external fixator. The THFx group also received blood pressure-controlled trauma hemorrhage (35 mmHg for 90 minutes) and reperfusion with Ringer's solution for 30 minutes. The Sham group received only the catheter and one external fixator. μCT scans of the femora were performed in vivo after 2 weeks and ex vivo after 3 weeks. Histological and biomechanical examinations were also carried out. The statistical significance was set at p ≤ 0.05. The non-normally distributed data were analyzed using the Mann-Whitney-U or Kruskal-Wallis test. Results. The histology showed less mineralized bone in the fracture gap in old animals of the Fx (25.41% [1.68%]) and THFx groups (25.50% [4.07%]) compared with the young ones (34.20% [6.36%], p = 0.003; 34.31% [5.12%], p=0.009). Moreover, a severe blood loss lead to more cartilage in both young (6.91% [5.08%]) and old animals (4.17% [1.42%]) compared to animals with only a fracture (2, 45% [1.04%], p=0.004; 2.95% [1.12%], p=0.032). In old animals (11.37 / nm. 2. [17.17 / nm. 2. ]) in contrast the young mice with an isolated fracture (33.6/nm. 2. [8.83/nm. 2. ]) fewer osteoclasts were present (p=0.009). Therefore, the severe blood loss further reduced the number of osteoclasts only in young animals (16.83/nm. 2. [6.07/nm. 2. ]) (p=0.004). In the in vivo μCT, after 2 weeks, a lower volume of bone, cortex and callus was found in old THFx animals (3.14 mm. 3. [0.64 mm. 3. ]); 1.01 mm. 3. [0.04 mm. 3. ]; 2.07 mm. 3. [0.57 mm. 3. ]) compared with the Fx animals (4.29 mm. 3. [0.74 mm. 3. ], p=0.008; 1.18 mm. 3. [0, 25 mm. 3. ], p=0.004; 3.02 mm. 3. [0.77 mm. 3. ], p=0.008) After 3 weeks, the ex vivo μCT scans also showed a reduced callus percentage in old THFx animals (61.18% [13.9 9%]), as well as a low number of trabeculae (1.81 mm. -1. [0.23 mm. -1. ]) compared to animals without blood loss (68.72% [15.71%], p = 0.030; 2.06mm. -1. [0.37mm. -1. ], p=0.041). In the biomechanical test, a reduced elasticity limit of the old THFx mice (7.75 N [3.33 N]) in contrast to the old Fx (10.24 N [3.32 N]) animals was shown (p=0.022). Conclusions. A severe blood loss has a higher negative effect on the healing, morphometry, and biomechanical properties of previously fractured femora in old compared to young individuals

Introduction: Computer navigation systems allow real time evaluation of knee behaviour intraoperatively. Measurements made by navigation reflect soft tissue balance throughout surgery. We studied three different populations of patients undergoing total knee replacement (TKR) with a CT-free navigation system where the goal was to achieve normal alignment. We compared the initial pathological kinematics in each group with the resultant kinematics after correction. Method: The Orthopilot® was used during TKR for three groups of patients A (n=71), B(n=60) and C(n=43) all with endstage osteoarthritis. Patients in groups A and B had TKR performed by surgeon 1, and group C by surgeon 2. Results: Pre-operatively, the mean mechanical femoral axis and the mean mechanical femoro-tibial (MFT) angle were calculated. The mean mechanical femoral axis for group A was −0.5° varus (−6° to 9°), group B was −0.68° varus(−6° to 6°), and for group C was 2.67° valgus (−12° to 10°). P< 0.0001, using Kruskal-Wallis test. Pre-operatively, the mean MFT angle for group A was −3.75° varus(−15° to 17°), group B was −2.98° varus(−17° to 13°), and for group C was 0.16° valgus(−17° to 25°). P=0.003 using Kruskal-Wallis test. These results show that the initial preoperative kinematics are different for the three different populations. Post-operatively we measured the mean MFT angle in groups A, B and C. In group A, the mean MFT angle was −0.38° varus (−4° to 2°), group B was −0.41° varus(−5° to 2°), and group C was −0.02° varus(−3° to 5°). P=0.7 using the Kruskal-Wallis test. These results show that the post-operative kinematics are similar between the three different populations. Discussion: Populations A and B preoperatively exhibited a mean varus MFT angle (−0.5° and −0.68° respectively), compared with a mean valgus MFT angle for group C(2.67°), which were statistically significantly different. Although different surgeons operated on the 3 groups (surgeon 1 operated on groups A and B, and surgeon 2 operated on group C), post-operative kinematics were within a narrow range (−0.02° to −0.41°) and not statistically different (p=0.7). Conclusion: The Orthopilot® results showed that these populations had different initial pathological kinematics. Despite this, and using different operators we obtained similar post-op results within a narrow range. Computer navigation produces reliable, reproducible results independent of population or operator variables

Introduction. Pseudotumors have been reported following metal-on-metal total hip arthroplasty (THA); however, the natural history and longitudinal imaging findings of pseudotumors have yet to be fully analyzed. Our hypothesis was that pseudotumor size might change over time following metal-on-metal THA. This hypothesis was studied longitudinally using magnetic resonance imaging (MRI). Materials and Methods. Screening for pseudotumors was performed using MRI after large-diameter metal-on-metal THA. Initial MRI was conducted at a mean of 36 months postoperatively. Follow-up MRI was performed at a mean of 20 months after the detection of 24 pseudotumors in 20 asymptomatic patients. Pseudotumors were classified as cystic, solid, and mixed types. Fourteen hips were characterized as cystic type and 10 hips were defined as mixed type. There were three men and 17 women with a mean age of 63 years. Pseudotumor size was determined on MRI by manually outlining the greatest size of the mass. Serum cobalt and chromium ion levels were measured in nine patients with unilateral THA at the time of MRI. Statistical analysis was performed using the Kruskal-Wallis test and chi square test to compare age, gender, BMI, head diameter, cup inclination, cup anteversion, and pseudotumor type among changes of pseudotumor size. We compared the pseudotumor size for the three groups (increase in size, no change, decrease in size) using Kruskal-Wallis test and Mann-Whitney U test. Wilcoxon signed-rank test was used to compare median serum metal ion levels over time. A p value < 0.05 was considered significant. This study was approved by the ethics committee of our institution, and all patients provided informed consent. Results. The mean pseudotumor size changed from 729 mm. 2. to 877 mm. 2. Among the 24 hips, pseudotumors increased in size (Fig. 1) in eight (three cystic and five mixed) and decreased in size in six (four cystic and two mixed). Ten hips showed no changes in size (seven cystic and three mixed). We found no significant differences between changes of pseudotumor size and patient characteristics. The mean initial size of pseudotumor was bigger in pseudotumors with increased in size (1002 ± 309 mm. 2. ) than in those with decreased in size (542 ± 295 mm. 2. , p = 0.020) or no change (622 ± 448 mm. 2. , p = 0.041). The median cobalt ion levels at initial MRI and follow-up MRI were 2.0 µg/L and 1.8 µg/L, respectively. The median chromium ion levels at initial MRI and follow-up MRI were 2.0 µg/L and 3.1 µg/L, respectively. No significant differences were observed between the levels of either metal at initial and subsequent MRI. Conclusions. The present results suggest that pseudotumors frequently change in size in asymptomatic patients, and our hypothesis was verified. The initial size of pseudotumor was bigger in pseudotumors with increased in size than in those with decreased in size or no change. And we might predict that bigger pseudotumors would tend to increase in size

Objectives. The use of the haptically bounded saw blades in robotic-assisted total knee arthroplasty (RTKA) can potentially help to limit surrounding soft-tissue injuries. However, there are limited data characterizing these injuries for cruciate-retaining (CR) TKA with the use of this technique. The objective of this cadaver study was to compare the extent of soft-tissue damage sustained through a robotic-assisted, haptically guided TKA (RATKA) versus a manual TKA (MTKA) approach. Methods. A total of 12 fresh-frozen pelvis-to-toe cadaver specimens were included. Four surgeons each prepared three RATKA and three MTKA specimens for cruciate-retaining TKAs. A RATKA was performed on one knee and a MTKA on the other. Postoperatively, two additional surgeons assessed and graded damage to 14 key anatomical structures in a blinded manner. Kruskal–Wallis hypothesis tests were performed to assess statistical differences in soft-tissue damage between RATKA and MTKA cases. Results. Significantly less damage occurred to the PCLs in the RATKA versus the MTKA specimens (p < 0.001). RATKA specimens had non-significantly less damage to the deep medial collateral ligaments (p = 0.149), iliotibial bands (p = 0.580), poplitei (p = 0.248), and patellar ligaments (p = 0.317). The remaining anatomical structures had minimal soft-tissue damage in all MTKA and RATKA specimens. Conclusion. The results of this study indicate that less soft-tissue damage may occur when utilizing RATKA compared with MTKA. These findings are likely due to the enhanced preoperative planning with the robotic software, the real-time intraoperative feedback, and the haptically bounded saw blade, all of which may help protect the surrounding soft tissues and ligaments. Cite this article: Bone Joint Res 2019;8:495–501

The literature indicates that femoroacetabular impingement (FAI) patients do not return to the level of controls (CTRL) following surgery. The purpose of this study was to compare hip biomechanics during stair climbing tasks in FAI patients before and two years after undergoing corrective surgery against healthy controls (CTRL). A total of 27 participants were included in this study. All participants underwent CT imaging at the local hospital, followed by three-dimensional motion analysis done at the human motion biomechanics laboratory at the local university. Participants who presented a cam deformity >50.5° in the oblique-axial or >60° in the radial planes, respectively, and who had a positive impingement test were placed in the FAI group (n=11, age=34.1±7.4 years, BMI=25.4±2.7 kg/m2). The remaining participants had no cam deformity and negative impingement test and were placed in the CTRL group (n=16, age=33.2±6.4 years, BMI=26.3±3.2 kg/m2). The CTRL group completed the biomechanics protocol once, whereas the FAI group completed the protocol twice, once prior to undergoing corrective surgery for the cam FAI, and the second time at approximately two years following surgery. At the human motion biomechanics laboratory, participants were outfitted with 45 retroreflective markers placed according to the UOMAM marker set. Participants completed five trials of stairs task on a three step instrumented stair case to measure ground reaction forces while 10 Vicon MX-13 cameras recorded the marker trajectories. Data was processed using Nexus software and divided into stair ascent and stair descent tasks. The trials were imported into custom written MatLab software to extract peak pelvis and hip kinematics and hip kinetic variables. Non-parametric Kruskal-Wallis tests were used to determine significant (p < 0.05) differences between the groups. No significant differences occurred during the stair descent task between any of the groups. During the stair ascent task, the CTRL group had significantly greater peak hip flexion angle (Pre-Op=58±7.1°, Post-Op=58.1±6.6°, CTRL=64.1±5.1°) and sagittal hip range of motion (ROM) (Pre-Op=56.7±6.7°, Post-Op=56.3±5.5°, CTRL=61.7±4.2°) than both the pre- and post-operative groups. Pre-operatively, the FAI group had significantly less peak hip adduction angle (Pre-Op=2±4.5°, Post-Op=3.4±4.4°, CTRL=5.5±3.7°) and hip frontal ROM (Pre-Op=9.9±3.4°, Post-Op=11.9±5.4°, CTRL=13.4±2.5°) compared to the CTRL group. No significant differences occurred in the kinetic variables. Our findings are in line with the Rylander and colleagues (2013) who also found that hip sagittal ROM did not improve following corrective surgery. Their study included a mix of cam and pincer-type FAI, and had a mean follow-up of approximately one year. Our cohort included only cam FAI and they had a mean follow-up of approximately two years, indicating with the extra year, the patients still did not show sagittal hip kinematics improvement. In the frontal plane, there was no significant difference between the post-op and the CTRL, indicating that the postoperative FAI reached the level of the CTRLs. This is in line with recent work that indicates a more medialized hip contact force vector following surgery, suggesting better hip stabilization

Introduction. It is well-known that wear debris generated by metal-on-metal hip replacements leads to aseptic loosening. This process starts in the local tissue where an inflammatory reaction is induced, followed by an periprosthetic osteolysis. MOM bearings generate particles as well as ions. The influence of both in human bodies is still the subject of debate. For instance hypersensitivity and high blood metal ion levels are under discussion for systemic reactions or pseudotumors around the hip replacement as a local reaction. The exact biopathologic mechanism is still unknown. The aim of this study was to investigate the impact of local injected metal ions and metal particles. Material and Methods. We used an established murine inflammation model with Balb/c mice and generated three groups. Group PBS (control group, n=10) got an injection of 50µl 0.1 vol% PBS-suspension, Group MI (Metal-ion, n=10) got an injection of 50µl metal ion suspension at a concentration of 200µg/l and Group MP (Metal-particles, n=10) got an injection of 50µl 0.1 vol% metal particle suspension each in the left knee. After incubation for 7 days the mice were euthanized and the extraction of the left knee ensued. Followed by immunhistochemical treatment with markers of inflammation that implied TNFα, IL-6, IL-1β, CD 45, CD 68, CD 3, we counted the positive cells in the synovial layer in the left knees by light microscopy, subdivided into visual fields 200× magnified. The statistical analysis was done with Kruskal-Wallis test and a post hoc Bonferroni correction. Results. The Group with metal particles showed significantly elevated inflammatory markers (TNFα, IL-6, IL-1β, CD 68, CD 45) compared to all other groups. Interestingly, CD 3 as a marker for T-lymphocytes showed no increased levels in all groups. The metal ion group showed significant elevated CD 45 expressions compared to the control group. Conclusion. The results clearly demonstrate that especially metal wear particles lead to an intensive inflammatory reaction. The tissue formations in the metal particle group show an osseous destructive behavior in previously demonstrated results, comparable to pseudotumors. But, in this study, the expression of the immunohistological markers CD 3, CD 45 and CD 68 indicate that the tissue consists of leucocytes and macrophages, whereas lymphocytes could not be detected. This might be due to an acute inflammatory reaction, whereas the adaptive immune response by T-lymphocytes seems not (yet) to be activated. Overall it must be stated that solid metal wear particles are responsible for local inflammatory reactions, whereas it is still unknown whether wear particles corrode in vivo and release a potentially high level of locally toxic metal ions

Healthy cartilage is essential for optimal joint function. Although, articular cartilage defects are highly prevalent in the active population and might hamper joint function, the effect of articular cartilage defects on knee contact forces and pressures is not yet documented. Therefore, the present study compared knee contact forces and pressures between patients with a tibiofemoral cartilage defect and healthy controls. This might provide additional insights in movement adaptations and the role of altered loading in the progression from defect to OA. Experimental gait data was collected in 15 patients with isolated articular cartilage defects (8 medial-affected, 7 lateral-affected) and 19 healthy asymptomatic controls and was processed using a musculoskeletal model to calculate contact forces and pressures. Differences between medial-affected, lateral-affected and controls were evaluated using Kruskal-Wallis tests and individually compared using Mann-Whitney-U tests (alpha <0.05). The lateral-affected group walked significantly slower compared to the healthy controls. No adaptations in the movement pattern that resulted in decreased loading on the injured condyle were observed. Additionally, the location of loading was not significantly affected. The current results suggest that isolated cartilage defects do not induce changes in the knee joint loading pattern. Consequently, the involved condyle will be equally loaded, indicating that a similar amount of force should be distributed over the remaining cartilage surrounding the articular cartilage defect and may cause local degenerative changes in the cartilage. This in combination with inflammatory responses might play a key role in the progression from articular cartilage defect to a more severe OA phenotype