Establishing minimal important change (MIC) thresholds is crucial in orthopedics for interpreting patient-reported outcome measure (PROM) data. Various methods have emerged to determine MIC, each with its own advantages and drawbacks. However, MIC values for PROM to assess patients undergoing arthroscopic rotator cuff repair (ARCR) in Switzerland remain unclear. This study aims to compare MIC values using three different methods for the Oxford Shoulder Score (OSS) among ARCR patients in Switzerland.

Methods

Between June 2020 and November 2021, 973 primary ARCR patients were prospectively enrolled in a multicenter cohort across 18 Swiss and one German orthopedic center. OSS data were collected at 6- (N = 910), 12- (N = 873), and 24-month (N = 854) follow-ups. We used a 5-item Likert anchor question to assess subjective shoulder function. We assessed the ceiling effect of OSS, the proportion of minimally improved patients, and the present state bias (PSB). Three methods (receiver operating characteristics-based, predictive modeling, adjusted predictive modeling) were compared to establish MIC values.
Results
The proportion of minimally improved patients was 86%, 93%, and 94% at 6-, 12-, and 24-month follow-up. Ceiling effect occurred in 9%, 30%, and 42% at the respective timepoints. PSB was 0.56, 0.65, and 0.75. MIC values ranged from 5 to 8 points at 6-month follow-up, increasing to 10-14 points at 12- and 24-month follow-ups.

Conclusions

Our study highlighted that nearly all patients with available data at follow-up experienced a minimal improvement after an ARCR in Switzerland. We found that an OSS improvement of between 10 and 14 points at the 12- and 24-month follow-up was sufficient to categorize patients as being minimally improved in the Swiss population, a high threshold in comparison to other reported values in the literature. The large proportion of minimally improved patients, ceiling effects, and PSBs in our setting suggest that our MIC estimates may be overestimated. Alternative analytical approaches addressing these issues should be considered.

Introduction
Patient reported outcomes (PROs) are typically used as summary scores without considering individual items.
This study aims to evaluate and compare the influence of WOMAC Pain and Function summary scores as well as individual items on patient satisfaction one year after total hip (THA) and knee arthroplasty (TKA).

Methods
All patients who underwent primary elective THA or TKA at a tertiary hospital between 01.01.2012 and 30.06.2022 were included. Main outcomes were patient satisfaction (5-point Likert scale) and the short-form WOMAC questionnaire (12-item scale) one year after surgery. Ordinal logistic regression models were used for the analysis.

Results
1772 THAs (55.4% women, mean age 68.8) and 1323 TKAs (63.7% women, mean age 70.9) were included. In both populations, both WOMAC summary scores and all items were associated individually with patient satisfaction. However, WOMAC Pain showed a greater impact than WOMAC Function (THA t-values: 12.89 and 3.61; TKA t-values: 12.43 and 2.04 respectively). Moreover, some items showed stronger associations than others. Two pain items in both populations – “walking on flat” and “going up/down stairs” – stood out showing the strongest associations. Three function items, different for each population – “ascending stairs”, “walking on flat”, “putting on socks” for THA and “rising from sitting”, “walking on flat”, “getting in/out of car” for TKA – stood out with the strongest associations.

Conclusion
With regard to patient satisfaction, the results support the validity and sensitivity to context of the WOMAC scales. Overall, both summary scores were strongly associated with satisfaction, but pain during activities had more influence on satisfaction than functional abilities. The 12 WOMAC items varied in their associations with overall satisfaction. For pain-specific items, between-item differences were the same after THA and TKA, but for function-specific items patterns varied between THA and TKA, reflecting the strain that each activity imposes upon each joint. Overall, considering two pain items and three function items might be sufficient in some settings as their association with patient satisfaction was similar to the WOMAC summary scores.

Introduction: In vitro joint simulators are commonly used to assess joints in native, injured, and reconstructed conditions. Robotic platforms now appear as the new gold standard to explore all degrees of freedom of a joint in a reliable and accurate manner. They allow for controlling joints in force or displacement and have been applied to hip, knee, spine, and shoulder joint assessment. Current approaches are most frequently dedicated to study of a unique isolated joint, mainly oriented towards an accurate force control, and requesting precise alignment of anatomical and robotic axes. The purpose of this study is to present a versatile robotic testing platform allowing advanced biomechanical analyses of multiple joints while inducing physiological motions and/or forces.

Methods: The platform is composed of a robotic manipulator equipped with a six-axis universal force-moment sensor, a Tripteron-type parallel robot driven by linear actuators, an optical motion capture system, and bespoke bone holders. A calibration process allows the robotic platform and motion capture system to share the same coordinate system. Requested joint motions can be defined 1) by reproducing operator-induced joint testing or 2) by generating trajectories around anatomical axes. Requested joint contact forces can be defined in the distal or proximal bone coordinate systems. Bespoke bone holders allow for positioning anatomical pieces without requiring precise alignment between anatomical and robotic/sensor axes.

Results: The robotic platform demonstrated a reliability of 0.28 ± 0.57 mm and 0.15 ± 0.25°, and fidelity of 0.27 ± 0.56 mm and 0.22 ± 0.28° to produce requested joint motions. It has been applied to shoulder and wrist joints with current research and development in hip joint biomechanics. In particular, the platform has already allowed to identify optimal acromioclavicular joint reconstruction surgical steps and construct design on joint alignment and kinematics. To date, both isolated joint and whole cadaver conditions have been tested, with or without removing soft tissues, demonstrating the high versatility of the platform.

Conclusion & perspectives: By allowing the reproduction of physiological joint motions and contact forces in a reliable way, the robotic platform open new avenues in the exploration of joints in native, injured, reconstructed, and replaced conditions. This platform will now be used to compare and validate surgical procedures and medical devices.

Background - The administrative burden in healthcare is a major contributor to physician burnout, deteriorating patient care and increasing costs. Recently, large language models like ChatGPT-4 have emerged.Large language models like ChatGPT-4 have emerged. They hold the potential of reducing the administrative burden by optimizing the generating everyday creation of clinical documents, and thus allowing the physician to spend more time with the patient. We aimed to assess both the quality and efficiency of discharge documents generated by ChatGPT-4 in comparison with those produced by physicians.

Methods – To emulate real-world situations, the health records of 6 fictional orthopedic cases were created. Discharge documents for each case were generated by a junior attending orthopedic surgeon and an advanced orthopedic resident. Then ChatGPT-4 was prompted to generate the discharge documents using the same health record information. The quality assessment was performed by an expert panel (n = 15) blinded to the source of the documents. As secondary outcome, the time required to generate the documents was compared logging the duration in the creation of the discharge documents by the physician and by ChatGPT-4.

Results – After exclusion, the panel conducted a total of 126 evaluations. 6 were discarded. Of the documents produced by ChatGPT-4, most (38 assessments) were deemed suitable for clinical use. Some required corrections (21 assessments), while a small number (2 assessments) were deemed unsuitable for clinical use. In contrast, human-generated notes were evaluated 32 times as suitable for clinical use, received 25 indications for corrections, and were considered unsuitable for clinical use on 2 occasions. There were 4 instances of hallucinations in GPT-4-crafted content, in contrast to 6 in human generated documents. ChatGPT-4 generated discharge documents 10 times faster than the traditional manual method.

Conclusion – ChatGPT-4 creates orthopedic discharge notes faster than doctors, with comparable quality. This shows it has great potential for making these documents more efficiently in orthopedic care. Although further evaluation using a larger sample size and real patient data is essential, ChatGPT-4 has the potential to significantly reduce the administrative burden on healthcare professionals.

Introduction:
In osteoarthritis (OA), articular cartilage follows progressive degeneration, where low-grade inflammation plays a pivotal role via exposure to reactive oxygen species (ROS). In chondrocytes, the only cells in cartilage, NADPH oxidase 4 (NOX4) is a major producer of ROS, significantly impacting regulation of catabolism. Our prior study showed that NOX4 deletion reduces cartilage degradation and regulates the anabolism/catabolism balance. As IL-1β is a key cytokine involved in OA, we hypothesize that NOX4 may influence the IL-1β secretion pathway through the NLRP3 inflammasome. This study evaluates the mechanisms of NOX4-induced OA in mice.

Methods:
OA was induced in vivo by destabilization of the medial meniscus (DMM) in WT and NOX4-/- mice. After 8 weeks, mice were sacrificed for immuno-histo-chimistry (IHC) analysis. Femoral heads from 9/10-week-old mice were cultured for 72 hours with PBS or IL-1β to induce OA ex vivo. Primary chondrocytes (PC) extracted from 4/6-day-old pups femoral heads and knees were cultured for 24 hours with PBS or IL-1β to induce OA in vitro. IL-6, IL-18, and MMP3 were quantified in ex vivo and in vitro supernatants by ELISA. Sulfated glycosaminoglycans (sGAG) concentration was assessed in supernatants by colorimetric dosage. Genes expressions of PC were quantified by RTqPCR.

Results:
IHC revealed stronger IL-1β and NLRP3 expression after DMM surgery in WT compared to NOX4-/- mice. In PC supernatant, we observed an IL-18 increase post IL-1β in WT but not in NOX4-/-.
In WT, RTqPCR showed a decreased anabolism genes transcription (AGG, COL2, SOX9) and NOX4 and increased catabolism and inflammation genes transcription (MMP3, MMP13, ADAMTS4, ADAMTS5, and IL-1, IL-6, TNF, COX2) post IL-1β.
In ex vivo supernatants, we observed increased IL-6 and sGAG concentration post IL-1β. In vitro, we observed increased MMP3, IL6, and decreased sGAG concentration in supernatants post IL-1β.
In NOX4-/- compared to WT, post IL1-β, we observed lower ADAMTS4/5 and IL1-β transcription, higher COX2 and IL6 transcription, but no IL6 concentration increase in supernatant. In the PC supernatants, we found a lower sGAG concentration.

Conclusion:
We demonstrate that NOX4 deletion inhibits NLRP3 inflammasome activation and IL-18 secretion. We showed that NOX4 deficiency inhibits ADAMTS gene expression. These results underline that NOX4 could aggravate OA by activating ADAMTS enzymes via the NLRP3/IL-18 pathway.

Introduction:
The effects of THA/TKA can be calculated as treatment effects (proportional symptom reduction). TE= symptom reduction/baseline symptoms; 1= complete reduction, 0= unchanged, >0= increased symptoms. We wanted to analyse the effects of THA/TKA in a registry with clinical assessment and compare them with trial results.
Methods:
All patients with THA/TKA in Kt. Zurich and complete data in SIRIS registry were included. Since 07/2019 all patients with THA/TKA had to fill out a Euro-QoL 5D questionnaire (assessing mobility/self-care/usual activities/pain-discomfort/anxiety-depression). The Euro-QoL score was calculated according to a defined algorithm before and 1 year after surgery. The treatment effect was calculated for each THA/TKA.
Results:
From July 2019 to December 2023, 5121 THA patients with a mean age of 68.8 years, 54% women, and 4375 TKA patients with a mean age of 70 years, 58.2% women, could be included. The effects varied from 1 to -1 for THA and from 1 to -1 for TKA. For THA, 4793 (93.6%) patients had an improvement, 236 remained unchanged (4.6%) and 92 had more symptoms (1.8%). For TKA, 3684 patients (84.2%) had an improvement, 503 remained unchanged (11.5%) and 188 had more symptoms (4.3%).
The published study results for THR were 91% improvement (KSA) and 85.4% improvement in EUROHIP. The results for TKA were 81% improvement (KSA) and 85.8% (Dresden registry).
Conclusion:
The effects of THA/TKA can be measured and demonstrate the variability of individual results. The results of THA in the canton of Zurich are comparable to those in studies and show that THA is a "winning operation". The results of TKA in the Canton Zurich are also comparable or even slightly better than in studies. Further analysis of the treatment processes may reveal important confounding factors.

Introduction:
Pain localization is important information for diagnosis in orthopedic/spine patients. It can be assessed through questions about neck-arm pain, back-leg pain, or pain-drawing (which can be difficult to evaluate). A new method was used to assess pain using a mannequin with a grid of 105 localizations on the body surface, which were then evaluated as a sum. This study presents a description of the method, grid, and results of an observational analysis. The correlation between pain localizations and symptom scores is examined.
Methods:
The study included all patients with spinal/orthopedic pathologies and mixed conditions. Patients marked their pain localizations on a semi-oblique mannequin (front and back). The body surface was divided into palm-sized elements or clearly defined locations (total of 105 elements). The questionnaires were analyzed digitally. The symptom score (0 to 100) was calculated as the sum of intensities of five symptoms: difficulties getting up, pain during daily activities, night pain, muscle weakness/instability, and sensory disturbances/cramps. The analysis and statistics were conducted at ETH Zurich. The study analyzed men and women separately due to slightly higher symptom scores in women. The correlation between the number of pain localizations and symptom score was analyzed using the Spearman correlation coefficient (rho).
Results:
The study included 4236 assessments from October 2016 to May 2023, with 2340 women (55.2%). The mean pain localizations were 5.25 for women (4.84 men), with a median of 3 pain localizations for both genders. The mean symptom score was 36.29 for women (32.56 for men). The correlation between pain localizations and symptom scores was high (rho=0.59 for women, 0.66 for men).
Conclusion:
Pain localizations can be easily assessed and analyzed using a pain drawing mannequin and grid in routine practice. Women tend to have more pain localizations and a higher symptom score. There is a strong linear relationship between pain localizations and symptom score. The combination of pain localizations and symptoms has great potential for diagnosis (It is important to note that this is only a first impression and further evaluation is necessary. < =3 pain localizations and score < 40 for osteoarthritis, > 5 pain localizations and score > 50 for neuropathy)

Introduction
Since the introduction of computer assisted surgery (CAS) in total knee arthroplasty there has always been critique about increased cost. 4 years ago, we published a cost analysis of four different computer assisted technologies to implant a total knee arthroplasty in comparison to conventional instrumentation and the use of image-based robotics has shown additional costs of 2600 CHF / case. Since then the method has become the new gold standard for TKA in our unit.

Methods
All the additional costs for image-based robotic compared to conventional TKA were re-evaluated for calculation. Some were deriving from the new contract with the company in 2023, some were collected in the OR and compared to the costs in 2018. Costs for OR time were set to 15 USD per minute, an additional tray to 210 USD, a CT scan to 420 USD as in 2018. Since 2018 we changed to cementless fixation in 95% of the TKA cases which reduced OR time by 15 minutes in mean (-225 USD) and such equalized OR time of a conventional TKA.

Results
Additional costs for one tray with specific instruments (+160 USD), additional OR time of 14 min for computer navigation, calibration, registration, adjusting the preset surgical plan (+210 USD). The cost for the preoperative CT scan decreased to 300 USD (-120 USD or minus 28%).
The costs for disposables were 600 USD in 2018 and increased to 766 USD in 2023 (+166 USD). Due to the new contract the costs for the technology itself (leasing contract, costs for the technician) could be reduced from 1210 USD in 2018 to 770 USD in 2023 (-440 USD or minus 36%).
By switching from cemented TKA in 2018 to mainly cementless in 2023 OR time could be reduced by 15 min (-225 USD) equalizing mean OR time for a conventional TKA.
Additional costs for image-based robotic TKA could be reduced from in mean 2180 USD in 2018 to 1681 USD in 2023 (minus 22%) in the OR itself or from totally 2600 USD in 2018 to 1981 USD (minus 23%) in average when including costs for the preoperative CT scan.

Conclusion
Total additional costs for image-based robotic TKA could be reduced by 23% in 5 years’ time due to negotiation after doubling the cases and increasing efficiency in OR by declaring the technology to the new gold standard and converting to mainly cementless fixation although costs for disposables increased by 28% during the same period.

Minimally invasive surgical techniques, including endoscopic and robotic procedures, continue to revolutionize patient care, for their ability to minimize surgical trauma, thus promoting faster recovery and reduced hospital stays. Yet, the suturing of soft tissues ensuring damage-free tissue bonding dur-ing these procedures remains challenging due to missing haptics and the fulcrum effect. Laser tissue soldering has potential in overcoming these issues, offering damage-free seamless tissue fusion. To en-sure the precision and safety of laser tissue soldering, we introduce feedback controlled fluorescent nanothermometry-guided laser tissue soldering using nanoparticle-protein solders within endoscopic and robotic contexts. Temperature-sensitive fluorescent nanoparticles embedded in the solder provide surgeons with immediate feedback on tissue temperatures during laser application, all while within the confines of minimally invasive surgical setups. By integrating fluorescent nanothermometry-guided laser tissue surgery into endoscopic and robotic surgery, we pave the way for a new approach for safe and atraumatic soft tissue joining, especially in regions where traditional suturing is unfeasible.