Learning curve for new technology?: a nationwide register-based study of 46,363 total knee arthroplasties

Digital TKA Alignment Training with a New Digital Simulation Tool (Knee-CAT) Improves Process Quality, Efficiency, and Confidence

Individual alignment techniques have been introduced to restore patients' unique anatomical variations during total knee arthroplasty. The transition from conventional mechanical alignment to individualised approaches, with the assistance of computer and/or robotic technologies, is challenging. The objective of this study was to develop a digital training platform with real patient data to educate and simulate various modern alignment philosophies. The aim was to evaluate the training effect of the tool by measuring the process quality and efficiency, as well as the post-training surgeon's confidence with new alignment philosophies. Based on 1000 data sets, a web-based interactive TKA computer navigation simulator (Knee-CAT) was developed. Quantitative decisions on bone cuts were linked to the extension and flexion gap values. Eleven different alignment workflows were introduced. A fully automatic evaluation system for each workflow, with a comparison function for all workflows, was implemented to increase the learning effect. The results of 40 surgeons with different experience levels using the platform were assessed. Initial data were analysed regarding process quality and efficiency and compared after two training courses. Process quality measured by the percentage of correct decisions was increased by the two training courses from 45% to 87.5%. The main reasons for failure were wrong decisions on the joint line, tibia slope, femoral rotation, and gap balancing. Efficiency was obtained with a reduction in time spent per exercise from 4 min 28 s to 2 min 35 s (42%) after the training courses. All volunteers rated the training tool as helpful or extremely helpful for learning new alignment philosophies. Separating the learning experience from OR performance was mentioned as one of the main advantages. A novel digital simulation tool for the case-based learning of various alignment philosophies in TKA surgery was developed and introduced. The simulation tool, together with the training courses, improved surgeon confidence and their ability to learn new alignment techniques in a stress-free out-of-theatre environment and to become more time efficient in making correct alignment decisions.

Correlation between component alignment and short-term clinical outcomes after total knee arthroplasty

OBJECTIVE

This study aimed to investigate the correlation between component alignment and short-term clinical outcomes after total knee arthroplasty (TKA).

METHODS

50 TKA patients from a regional hospital were enrolled in the study. The following component alignments were measured from radiological data acquired within 1 week after surgery: hip-knee-ankle angle (HKA), medial distal femoral angle (MDFA), medial proximal tibial angle (MPTA), femoral flexion-extension angle (FEA), tibial slope angle (TSA), femoral rotational angle (FRA) and tibial rotational angle (TRA). The Hospital for Special Surgery (HSS) knee scoring system was used to assess clinical outcomes after 1 year, with patients being divided into three groups (excellent, good and not good) according to the HSS scores. Difference analysis and linear correlation analysis were used for the statistical analysis.

RESULTS

The results showed significant differences in MDFA (p = 0.050) and FEA (p = 0.001) among the three patient groups. It was also found that the total HSS had only a moderate correlation with FEA (r = 0.572, p < 0.001), but FEA had a positive linear correlation with pain scores (r = 0.347, p = 0.013), function scores (r = 0.535, p = 0.000), ROM scores (r = 0.368, p = 0.009), muscle scores (r = 0.354, p = 0.012) and stability scores (r = 0.312, p = 0.028). A larger MDFA was associated with lower FE deformity scores (r = -0.289, p = 0.042) and the TSA had a positive influence on the ROM (r = 0.436, p = 0.002). Also, changes in FRA produced a consequent change in the FE deformity score (r = 0.312, p = 0.027), and the muscle strength scores increased as TRA increased (r = 0.402, p = 0.004).

CONCLUSION

The results show that the FEA plays a significant role in clinical outcomes after TKA. Surgical techniques and tools may need to be improved to accurately adjust the FEA to improve joint functionality and patient satisfaction.

Immersive technologies for total knee arthroplasty surgical education

The need to adapt surgical curricula to meet the demands of an increasingly restrictive training environment is rising. Modern constraints of surgical trainees including work-hour restrictions and concerns surrounding patient safety have created an opportunity to supplement traditional teaching methods with developing immersive technologies including virtual and augmented reality. Virtual reality (VR) and augmented reality (AR) have been preliminarily investigated as it relates to total joint arthroplasty. The purpose of this article is to discuss VR and AR as it applies to modern total knee replacement (TKR) surgical education.

Dual surgeon operating lists for complex revision arthroplasty surgery: changing orthopaedic surgical practice

There is an increasing trend towards dual surgeon operating in complex surgeries in various specialties. This is driven by regionalisation of services, increasing complexity of surgical procedures, the ageing population and challenges imposed by changes in surgical training. Dual surgeon cases have lower complication rates and better quality of patient care. This practice not only facilitates professional and personal development, but also provides valuable support to surgeons in the early part of their career. There is a paucity of literature to support this practice, however, and prospective studies are required to demonstrate the benefit of this approach.

Early clinical outcome and learning curve following unilateral primary total knee arthroplasty after introduction of a novel total knee arthroplasty system

BACKGROUND

New implants for total knee arthroplasty (TKA) are continuously introduced with the proposed benefit of increased performance and improved outcome. Little information exists on how the introduction of a novel arthroplasty implant affects the perioperative and surgical outcome immediately after implementation.

AIM

To investigate how surgery-related factors and implant positioning were affected by the introduction of a novel TKA system.

METHODS

A novel TKA system was introduced at our institution on 30th November 2015. Seventy-five TKAs performed with the Persona TKA immediately following its introduction by 3 different surgeons (25 TKAs/surgeon) were identified as the Introduction Group. Moreover, the latest 25 TKAs performed by each surgeon prior to introduction of the Persona TKA were identified as the Control Group. A Follow-up Group of 25 TKAs/surgeon was identified starting 1-year after the end of the introduction period. Demographics, surgery-related factors and alignment data were recorded, and intergroup differences compared.

RESULTS

Following introduction of the novel implant, Persona TKA was utilized in 69% (71%), 53% (54%), and 45% (75%) of primary TKA procedures by the three surgeons, respectively (Follow-up Group). Mean surgery time was increased by 28% (P < 0.0001) and mean intra-operative blood loss by 25% (P = 0.002) in the Introduction Group, while only the mean surgery time was increased in the Follow-up Group by 18% (P < 0.0001). Overall alignment was similar between the groups apart from femoral flexion (FF) and tibial slope (TS). The number of FF outliers was reduced in the Introduction Group with a more pronounced decrease in the Follow-up Group.

CONCLUSION

Introduction of the new TKA implant increased surgical time and intraoperative blood loss immediately after its introduction. These differences diminished one year after introduction of the new implant. Fewer outliers with respect to FF and TS were seen when using the novel TKA implant. Further studies are needed to investigate if these differences persist over time and correlate with patient reported outcomes.

How should new orthopaedic implants be introduced: an example and recommendations for best practice

Continued advancements in orthopaedics have led to the development of many new implants; many of these are being utilized in clinical practice with little or no evidence base for their safety or effectiveness. Highly publicized failures in orthopaedic technology have led to an increased awareness of this issue in both medical and non-medical circles. In most cases, the significant harm caused to the public could have been avoided by the appropriately staged implementation of new implants. This review comments on the current literature regarding the optimal practice for the introduction of new orthopaedic technology. The authors' experience with the failed ESKA Adapter Short-stem/Modular Hip is described; the methodology used for its evaluation is used as a basis to discuss what was successful about the process and also give warning on what could be improved upon. The ideal practice requires new orthopaedic implants to be evaluated by high-volume surgeons in specialist orthopaedic hospitals. These studies should include biomechanical studies, radiostereophotometric analysis, implant retrieval and outcome assessment. Results and complications should be reported early to the appropriate joint registry and regulatory body. Once a suitable evidence base has developed, the implant can be distributed into wider clinical practice or withdrawn. These recommendations aim to protect the patient and public from harm while allowing surgical innovation to still continue.

Learning Curve and Clinical Outcomes of Performing Surgery with the InterTan Intramedullary Nail in Treating Femoral Intertrochanteric Fractures

Purpose. The purpose of this study is to evaluate the learning curve of performing surgery with the InterTan intramedullary nail in treating femoral intertrochanteric fractures, to provide valuable information and experience for surgeons who decide to learn a new procedure. Methods. We retrospectively analyzed data from 53 patients who underwent surgery using an InterTan intramedullary nail at our hospital between July 2012 and September 2015. The negative exponential curve-fit regression analysis was used to evaluate the learning curve. According to 90% learning milestone, patients were divided into two group, and the outcomes were compared. Results. The mean operative time was 69.28 (95% CI 64.57 to 74.00) minutes; with the accumulation of surgical experience, the operation time was gradually decreased. 90% of the potential improvement was expected after 18 cases. In terms of operative time, intraoperative blood loss, hospital stay, and Harris hip score significant differences were found between two groups (p = 0.009, p = 0.000, p = 0.030, and p = 0.002, resp.). Partial weight bearing time, fracture union time, tip apex distance, and the number of blood transfusions and complications were similar between two groups (p > 0.5). Conclusion. This study demonstrated that the learning curve of performing surgery with the InterTan intramedullary nail is acceptable and 90% of the expert's proficiency level is achieved at around 18 cases.

Ten-Year Outcome Comparison of the Anatomical Graduated Component and Vanguard Total Knee Arthroplasty Systems

The development of a new total knee system as a successor prosthesis in total knee arthroplasty (TKA) requires clinical outcome improvement. 10,843 TKAs were performed of which 9169 utilized the Anatomical Graduated Component (AGC) and 1674 utilized the Vanguard prosthesis (both Biomet, Warsaw, IN). Survival rates at ten years postoperatively for the AGC and Vanguard were 98.7% and 98.4% (P=.4897) respectively. The top reasons for component failure were loosening (AGC: 0.29%, Vanguard: 0.30%), polyethylene wear, and instability (AGC: 0.13%, Vanguard: 0.12%). These results reveal similar outcomes in both designs, with relatively few revisions and high survival rates at ten years postoperatively.

SUMMARY

This abstract offers data concerning the usefulness of the Vanguard Total Knee System as a successor to the Anatomical Graduated Component.

Comparative Epidemiology of Revision Arthroplasty: Failed THA Poses Greater Clinical and Economic Burdens Than Failed TKA

BACKGROUND

Revision THA and TKA are growing and important clinical and economic challenges. Healthcare systems tend to combine revision joint replacement procedures into a single service line, and differences between revision THA and revision TKA remain incompletely characterized. These differences carry implications for guiding care and resource allocation. We therefore evaluated epidemiologic trends associated with revision THAs and TKAs.

QUESTIONS/PURPOSES

We sought to determine differences in (1) the number of patients undergoing revision TKA and THA and respective demographic trends; (2) differences in the indications for and types of revision TKA and THA; (3) differences in patient severity of illness scoring between THA and TKA; and (4) differences in resource utilization (including cost and length of stay [LOS]) between revision THA and TKA.

METHODS

The Nationwide Inpatient Sample (NIS) was used to evaluate 235,857 revision THAs and 301,718 revision TKAs between October 1, 2005 and December 31, 2010. Patient characteristics, procedure information, and resource utilization were compared across revision THAs and TKAs. A revision burden (ratio of number of revisions to total number of revision and primary surgeries) was calculated for hip and knee procedures. Severity of illness scoring and cost calculations were derived from the NIS. As our study was principally descriptive, statistical analyses generally were not performed; however, owing to the large sample size available to us through this NIS analysis, even small observed differences presented are likely to be highly statistically significant.

RESULTS

Revision TKAs increased by 39% (revision burden, 9.1%-9.6%) and THAs increased by 23% (revision burden, 15.4%-14.6%). Revision THAs were performed more often in older patients compared with revision TKAs. Periprosthetic joint infection (25%) and mechanical loosening (19%) were the most common reasons for revision TKA compared with dislocation (22%) and mechanical loosening (20%) for revision THA. Full (all-component) revision was more common in revision THAs (43%) than in TKAs (37%). Patients who underwent revision THA generally were sicker (> 50% major severity of illness score) than patients who underwent revision TKA (65% moderate severity of illness score). Mean LOS was longer for revision THAs than for TKAs. Mean hospitalization costs were slightly higher for revision THA (USD 24,697 +/- USD 40,489 [SD]) than revision TKA (USD 23,130 +/- USD 36,643 [SD]). Periprosthetic joint infection and periprosthetic fracture were associated with the greatest LOS and costs for revision THAs and TKAs.

CONCLUSIONS

These data could prove important for healthcare systems to appropriately allocate resources to hip and knee procedures: the revision burden for THA is 52% greater than for TKA, but revision TKAs are increasing at a faster rate. Likewise, the treating clinician should understand that while both revision THAs and TKAs bear significant clinical and economic costs, patients undergoing revision THA tend to be older, sicker, and have greater costs of care.

Ethical challenges in orthopedic surgery

Despite our recent attention to ethical issues in orthopedics, we are still faced with multiple conflicts of interest that continue to pose ethical dilemmas to the practicing physician. Using four case scenarios, we review the potential conflicts of interest and the dilemmas posed by these frequently encountered situations. The ethical conflicts confronted in resident training, the introduction of new technology, physician advertising, and the obligations of the sports team physician are reviewed and discussed. The basic principles of medical ethics, including acting for the good of the patients and doing no harm, are discussed in the context of the four case scenarios.

Knee arthroplasty with a medial rotating total knee replacement. Midterm clinical findings: a district general experience of 38 cases

BACKGROUND

The Medial Rotating Knee replacement (MRK) was first used in 1994, reporting high rates of satisfaction. It is designed to replicate natural knee kinematics and improve stability and function. There are limited studies on the mid-term clinical outcomes, in particular in a district general hospital (DGH) environment. This is the first study that we are aware of that evaluates the learning curve of the implementation of this knee system in this environment.

PATIENTS/METHOD

Between 2007 and 2009 we performed 38 consecutive MRK replacements (MAT ORTHO, UK) in 36 patients. The mean follow-up was four years. Patients were evaluated clinically, using OKS and patient questionnaire and radiographically (good/acceptable/poor) to assess outcome.

RESULTS

Mean age was 73.0 years. Mean pre-operative OKS was 17.7 (range 8-29), which rose to 38.1 (range 23-48) at latest follow up (p<0.005). Overall 71% of the patients were either satisfied (29%) or very satisfied (42%). 81% felt an improvement of the ability to go up or down stairs and 92% felt stable. All poor radiographic and the majority of acceptable outcomes were experienced in the first 50% of cases.

CONCLUSION

The MRK can be successfully implanted in a DGH environment. It improves pain and function comparably to standard TKRs, however, subjective improvement may be higher. Radiographic evaluation shows an acceptable learning curve.

LEVEL OF EVIDENCE

Level IV case series.

Quality of outcome data in knee arthroplasty

BACKGROUND AND PURPOSE

Recent reports on developer bias in unicondylar knee arthroplasty led to concerns about quality of publications regarding knee implants. We therefore compared revision rates of registry and non-registry studies from the beginning of knee arthroplasty up to the present. We assessed the time interval between market introduction of an implant and emergence of reliable data in non-registry studies.

MATERIAL AND METHODS

We systematically reviewed registry studies (n = 6) and non-registry studies (n = 241) on knee arthroplasty published in indexed, peer-reviewed international scientific journals. The main outcome measure was revision rate per 100 observed component years.

RESULTS AND INTERPRETATION

For 82% of the 34 knee implants assessed, revision data from non-registry studies are either absent or poor. 91% of all studies were published in the second and third decade after market introduction. Only 5% of all studies and 1% of all revisions were published in the first decade. The first publications on revision rates of total knee arthroplasty (TKA) started 6 years after market introduction, and reliable data were found from year 12 onward in non-registry studies. However, in unicondylar knee arthroplasty (UKA) the first publications on revision rates could be found first 13 years after market introduction. Revision rates of TKA from non-registry studies were reliable after year 12 following market introduction. UKA revision rates remained below the threshold of registry indices, and failed to demonstrate adjustment towards registries. Thus, the superiority of registry data over non-registry data regarding outcome measurement was validated.

Registries in orthopaedics

The first nationwide orthopaedic registry was created in Sweden in 1975 to collect data on total knee arthroplasty (TKA). Since then, several countries have established registries, with varying degrees of success. Managing a registry requires time and money. Factors that contribute to successful registry management include the use of a single identifier for each patient to ensure full traceability of all procedures related to a given implant; a long-term funding source; a contemporary, rapid, Internet-based data collection method; and the collection of exhaustive data, at least for innovative implants. The effects of registries on practice patterns should be evaluated. The high cost of registries raises issues of independence and content ownership. Scandinavian countries have been maintaining orthopaedic registries for nearly four decades (since 1975). The first English-language orthopaedic registry was not created until 1998 (in New Zealand), and both the US and many European countries are still struggling to establish orthopaedic registries. To date, there are 11 registered nationwide registries on total knee and total hip replacement. The data they contain are often consistent, although contradictions occur in some cases due to major variations in cultural and market factors. The future of registries will depend on the willingness of health authorities and healthcare professionals to support the creation and maintenance of these tools. Surgeons feel that registries should serve merely to compare implants. Health authorities, in contrast, have a strong interest in practice patterns and healthcare institution performances. Striking a balance between these objectives should allow advances in registry development in the near future.