[Risk and complication profiles of orthogeriatric patients in elective hip and knee joint replacement]

BACKGROUND

The care of geriatric patients undergoing elective orthopedic surgery is becoming increasingly more important due to demographic trends. Compared to geriatric traumatology, however, there are still no established orthogeriatric care models in Germany and therefore hardly any scientific data. The aim of this study was to describe the risk and complication profiles in older patients with elective hip and knee replacements.

METHODS

In a prospective study data were collected from orthogeriatric patients with indications for elective hip and knee replacement surgery who fulfilled defined inclusion and exclusion criteria between January 2021 and August 2023 in the orthopedic department of a German university hospital for the descriptive analysis of risk and complication profiles. In addition to a preoperative and perioperative data analysis, a follow-up was conducted 4-6 weeks and 3 months postoperatively.

RESULTS

The surgical risk profile of the patient population analyzed was characterized by advanced age (78.4 ± 4.8 years), preobesity/obesity (76%), multimorbidity (7.4 ± 3.1 comorbidities), polypharmacy (7.5 ± 3.8 medications), immobility (short physical performance battery 7.1 ± 2.6), prefrailty/frailty (87%), frequent anticoagulation (22%) and a high number of potentially inappropriate medications (64%). Complication events mainly occurred within the first 7 days postoperatively and 90% of the events within this recording period were minor complications. The overall complication rate significantly decreased in the follow-up period.

CONCLUSION

Due to the high risk and complication profiles the routine use of orthogeriatric co-management models for elective orthopedic surgery should be considered in the future.

[SOG-Special Orthopedic Geriatrics : First interim results of a randomized controlled study on integrated orthogeriatric care in elective hip and knee arthroplasty]

BACKGROUND

To date, there are no adequate care concepts for geriatric patients undergoing elective orthopaedic surgery in Germany. The Special Orthopaedic Geriatrics (SOG) study evaluates for the first time in Germany the impact of comprehensive orthogeriatric co-management on the outcome of elderly patients with elective hip and knee replacements compared to standard orthopaedic care.

METHODS

The interim analysis of the ongoing study included 174 patients; 87 patients were randomized to the intervention group and 87 to the control group. The SOG care model consists of screening, preoperative assessment with preoperative intervention, fast-track surgery and multimodal perioperative care in the orthogeriatric team. The control group received standard orthopaedic care. Mobility, complications, and patient-reported outcome measures after surgery were compared.

RESULTS

The SOG group showed a clinically relevant improvement in mobility postoperatively compared to the control group at all time points (p < 0.01). The evaluation of complications showed a significant risk reduction for minor complications (p < 0.01), as well as a clear trend towards a risk reduction for major complications. Patient-reported outcome measures showed a significant improvement in joint function and general health-related quality of life both in the SOG group and the control group.

CONCLUSION

Integrated orthogeriatric care models such as SOG could improve the care of geriatric patients in elective orthopaedic surgery in the future and, above all, make it safer.

[Fast-Track-Arthroplasty]

INTRODUCTION

Essential components of fast-track or enhanced recovery programs in arthroplasty are the optimization of interdisciplinary organizational processes, as well as pre-, intra- and postoperative procedures in everyday clinical practice. The early postoperative mobilization of patients after joint replacement surgery is of central importance, with the aim of avoiding pain and complications. This article provides a detailed overview of fast-track procedures that have already been established in many units. Furthermore, it demonstrates the clinical advantages of FastTrack for total hip arthroplasty (THA) in an evidence-based manner within the framework of a randomized study design.

MATERIAL AND METHODS

194 primary THA patients were examined after randomization into two single-blinded groups; Fast-Track (n = 98) or conventional treatment path (n = 96). Mobilization was defined as the primary outcome parameter, measured in seconds using the Timed Up and Go Test (TUG). Secondary parameters were the achievable walking distance in meters and pain using the numerical rating scale (NRS). All parameters were recorded preoperatively and daily until the sixth postoperative day.

RESULTS

No complications or revisions were recorded within the first postoperative week. The fast-track group showed significantly better TUG values and walking distance results compared to the conventional group until the sixth postoperative day (p < 0.05, respectively). There was no significant difference regarding the pain assessment (NRS) (p > 0.05).

CONCLUSION

The use of Fast-Track in hip arthroplasty can evidently improve short-term postoperative clinical outcomes. This first prospective, single-blinded, randomized controlled study showed very good clinical results with comparable pain after FastTrack THA compared to a conventional treatment path. Fast-Track concepts are highly effective in terms of early mobilization and clinical outcome-without incurring a higher risk of complications in the short term.

[Navigation and robotics-current status and future implications]

INTRODUCTION

Both navigation systems and robotics enable greater precision in the implantation of an artificial knee joint. However, they do not improve clinical outcomes. We hypothesized that although implantation of a total knee arthroplasty results in reconstruction of the alignment in the coronal plane, the variable rotational tibial and variable translational femoral and tibial component positioning lead to a change in the remaining alignment parameters of the lower extremity. However, these parameters could be determined using a navigation system or robot and could represent future implications for these systems.

METHODS

The kinematics and the position between femur and tibia before and after implantation of a total knee arthroplasty were determined using a navigation system in nine healthy knee joints of Thiel-fixed whole-body cadavers.

RESULTS

After arthroplasty, there was no change in the natural coronal alignment. In extension and the early degrees of flexion, the rotational position of the femur relative to the tibia was altered. This also led to a change in the positioning of the medial and lateral epicondyle in relation to the tibia; while both epicondyles were positioned more laterally in relation to the tibia after arthroplasty, the lateral epicondyle was significantly more lateral in relation to the tibia up to 20° of flexion.

DISCUSSION

Following arthroplasty of a knee joint using the established technique, a good reconstruction of the coronal alignment was achieved with simultaneous changes in the alignment in both the rotational and translational directions between the femur and tibia. Using navigation as well as robotics, we would be able to quantify all alignment parameters and could achieve an alignment of the components or a reconstruction of the overall alignment in all six degrees of freedom. We might also be able to achieve a clinical advantage or increase the service life even further.

The impact of primary total hip and knee replacement on frailty: an observational prospective analysis

BACKGROUND

Osteoarthritis is a prevalent condition in frail older adults that requires hip or knee replacement in many patients. The aim of the study was to determine the impact of hip and knee arthroplasty on frailty.

METHODS

In this prospective short-term study, we used data from 101 participants of the ongoing Special Orthopaedic Geriatrics (SOG) trial, funded by the German Federal Joint Committee (GBA). Frailty, measured by Fried's Physical Frailty Phenotype (PFP), was assessed preoperatively, 7 days postoperatively, 4-6 weeks and 3 months after hip and knee arthroplasty. ANOVA with repeated measures and post-hoc tests for the subgroups were used for the statistical analysis.

RESULTS

Of the 101 participants, 50 were pre-frail (1-2 PFP criteria) and 51 were frail (≥ 3 PFP criteria) preoperatively. In the pre-frail group, the PFP score decreased from 1.56 ± 0.50 (median 2) preoperatively to 0.53 ± 0.73 (median 0) 3 months after surgery (p < 0.001). The PFP score in the frail cohort decreased from 3.39 ± 1.45 (median 3) preoperatively to 1.27 ± 1.14 (median 1) 3 months postoperatively (p < 0.001). While the PFP score of the pre-frail participants increased 7 days after surgery, the PFP score of the frail group decreased significantly.

CONCLUSION

Pre-frail individuals often regain robustness and patients with frailty are no longer assessed as frail after surgery. Joint replacement is an effective intervention to improve frailty in hip and knee osteoarthritis.

TRIAL REGISTRATION

This study is part of the Special Orthopaedic Geriatrics (SOG) trial, German Clinical Trials Register DRKS00024102. Registered on 19 January 2021.

[Navigated or conventional acetabular surgery : Comparison of positional accuracy exemplified by the infra-acetabular screw]

BACKGROUND

The principle of joint-preserving treatment of acetabular fractures is the anatomic reduction of joint-bearing elements and internal osteosynthesis. For stabilization of the anterior and posterior columns against each other, the infra-acetabular screw (IAS) is regularly used in the clinical routine.

OBJECTIVE

The aim of this study was to compare the position of the IAS in the infra-acetabular corridor after navigated placement and after freehand placement.

MATERIAL AND METHOD

The position of the screw was evaluated in 42 patients using multiplanar reconstructions. The screw was placed freehand in 30 patients and using image-guided navigation in 12 patients. In addition to measurement of the position of the screw, demographic data, operating time, radiation exposure and blood loss were recorded.

RESULTS

The vast majority of the patients were male (86%), the median age was 67 years and the median body mass index (BMI) was 25 kg/m2. The median operating time was 166 min and the median blood loss was 900 ml. The adjusted values in the whole sample considering the position of the screw were: distance of screw to cartilage mean value (m) = 3.8 mm, distance of screw to corridor center m = 3.5 mm and angle of screw to corridor m = 1.4°. There were no differences between the groups in the demographic parameters and the accuracy of positioning of the screw (p-value > 0.05). There was a longer irradiation time and a higher radiation dose in the navigated group compared to the group without navigation (p-value < 0.001).

CONCLUSION

With appropriate experience both procedures are comparable taking into account the accuracy. Taking into consideration other perioperative parameters, such as radiation exposure and planned operating time, patient-related factors should be taken into consideration.

Better early outcome with enhanced recovery total hip arthroplasty (ERAS-THA) versus conventional setup in randomized clinical trial (RCT)

INTRODUCTION

Numbers of total hip arthroplasty (THA) are steadily rising and patients expect faster mobility without pain postoperatively. The aim of enhanced recovery after Surgery (ERAS) programs in a multidisciplinary setup was to keep pace with the needs of quality and quantity of surgical THA-interventions and patients' expectations.

METHODS

194 patients undergoing THA procedures were investigated after single-blinded randomization to ERAS (98) or conventional setup group (96). Primary outcome variable was mobilization measured with the Timed Up and Go Test (TUG) in seconds. Secondary outcome variables were floor count and walking distance in meters as well as rest, mobilization and night pain on a numerous rating scale (NRS). All variables were recorded preoperatively and daily until the sixth postoperative day. To assess and compare clinical outcome and patient satisfaction, the PPP33-Score and PROMs were used.

RESULTS

No complications such as thromboembolic complications, fractures or revisions were recorded within the first week postoperatively in either study group. Compared to the conventional group, the ERAS group showed significantly better TUG (p < 0.050) and walking distance results after surgery up to the sixth, and floor count up to the third postoperative day. On the first and second postoperative day, ERAS patients showed superior results (p < 0.001) in all independent activity subitems. Regarding the evaluation of pain (NRS), PPP33 and PROMS, no significant difference was shown (p > 0.050).

CONCLUSION

This prospective single-blinded randomized controlled clinical trial was able to demonstrate excellent outcome with comparable pain after ERAS THA versus a conventional setup. Therefore, ERAS could be used in daily clinical practice.

[Outcome of joint replacement in patients with underlying rheumatoid disease]

BACKGROUND

Artificial joint replacement is a meaningful treatment option for patients with advanced rheumatic degenerative joint diseases. The aim of this study was to investigate the influence of the underlying rheumatic diseases on postoperative complications and patient-reported outcome (PRO) after elective total joint replacement (TJR).

MATERIAL AND METHODS

In a retrospective analysis of 9149 patients with elective total knee or total hip arthroplasty (TKR and THR), complication rates and PRO of patients with and without rheumatic diseases (RD) were compared. Multivariate logistic regression models were used to determine whether the underlying rheumatic disease was an independent risk factor for various complications.

RESULTS

In the univariate analyses the RD patients had an increased risk of medical complications (7.1% vs. 5.2%; p = 0.028) and Clavien-Dindo grade IV complications (2.8% vs. 1.8%; p = 0.048) after TJR. This was confirmed in multivariate statistical analyses (p < 0.034). The rates for operative revisions and surgical complications were comparable (2.5% vs. 2.4%; p = 0.485). Analysis of the PRO showed a higher responder rate in patients with RD after TKR (91.9% vs. 84.5%, p = 0.039). In contrast, the responder rate in patients with RD after THR was comparable (93.4% vs. 93.2%, p = 0.584).

CONCLUSION

Despite increased postoperative complication rates, patients with underlying rheumatic diseases showed a comparable outcome 1 year after TJR. After TKR the RD patients showed even higher responder rates. Although RD patients are a vulnerable patient group, they can still benefit from joint replacement.

Arthrosis diagnosis and treatment recommendations in clinical practice: an exploratory investigation with the generative AI model GPT-4

BACKGROUND

The spread of artificial intelligence (AI) has led to transformative advancements in diverse sectors, including healthcare. Specifically, generative writing systems have shown potential in various applications, but their effectiveness in clinical settings has been barely investigated. In this context, we evaluated the proficiency of ChatGPT-4 in diagnosing gonarthrosis and coxarthrosis and recommending appropriate treatments compared with orthopaedic specialists.

METHODS

A retrospective review was conducted using anonymized medical records of 100 patients previously diagnosed with either knee or hip arthrosis. ChatGPT-4 was employed to analyse these historical records, formulating both a diagnosis and potential treatment suggestions. Subsequently, a comparative analysis was conducted to assess the concordance between the AI's conclusions and the original clinical decisions made by the physicians.

RESULTS

In diagnostic evaluations, ChatGPT-4 consistently aligned with the conclusions previously drawn by physicians. In terms of treatment recommendations, there was an 83% agreement between the AI and orthopaedic specialists. The therapeutic concordance was verified by the calculation of a Cohen's Kappa coefficient of 0.580 (p < 0.001). This indicates a moderate-to-good level of agreement. In recommendations pertaining to surgical treatment, the AI demonstrated a sensitivity and specificity of 78% and 80%, respectively. Multivariable logistic regression demonstrated that the variables reduced quality of life (OR 49.97, p < 0.001) and start-up pain (OR 12.54, p = 0.028) have an influence on ChatGPT-4's recommendation for a surgery.

CONCLUSION

This study emphasises ChatGPT-4's notable potential in diagnosing conditions such as gonarthrosis and coxarthrosis and in aligning its treatment recommendations with those of orthopaedic specialists. However, it is crucial to acknowledge that AI tools such as ChatGPT-4 are not meant to replace the nuanced expertise and clinical judgment of seasoned orthopaedic surgeons, particularly in complex decision-making scenarios regarding treatment indications. Due to the exploratory nature of the study, further research with larger patient populations and more complex diagnoses is necessary to validate the findings and explore the broader potential of AI in healthcare.

LEVEL OF EVIDENCE

Level III evidence.

Comparison of postoperative isokinetic quadriceps and gluteal muscular strength after primary THA: is there an early benefit through enhanced recovery programs?

PURPOSE

Although total hip arthroplasty (THA) is expected to result in a postoperative loss of muscular strength, no study investigated the benefit of an enhanced-recovery-after-surgery (ERAS) concept on the hip muscles in detail. We evaluated if (1) an ERAS-concept for primary THA results in reduced loss of muscular strength five days and four weeks postoperative. We (2) compared the two groups regarding Patient-Related-Outcome-Measures (PROMs), WOMAC-index (Western-Ontario-and-McMaster-Universities-Osteoarthritis-Index), HHS (Harris-Hip-Score) and EQ-5d-3L-score.

METHODS

In a prospective, single-blinded, randomized controlled trial, we compared isokinetic muscular strength of 24 patients receiving primary THA with an enhanced recovery concept with early mobilization (n = 12, ERAS-group) and such receiving conventional THA (n = 12, non-ERAS). Isokinetic muscular strength was measured with a Biodex-Dynamometer before, as well as five days and four weeks after surgery (peak-torque, total-work, power). Furthermore, WOMAC, HHS, PROMs and EQ-5d-3L were imposed.

RESULTS

The ERAS group revealed significant higher isokinetic strength (peak-torque, total-work, power) at both time points. Both groups showed a significant pain decrease at both time points meeting very high rates of patient satisfaction resembled by good results in PROMs, WOMAC, HHS, EQ-5d. There was no significant difference in any of the scores between both groups.

CONCLUSION

We proved a significant reduced loss of muscular strength five days and four weeks after primary THA in combination with an ERAS concept. However, the reduced loss of muscular strength is not reflected by patient's functional outcome and quality of life, showing no significant differences in WOMAC, HHS, EQ-5d-3L, PROMs and NRS. Therefore, this study supports the implementation of an ERAS concept for primary THA in terms of isokinetic strength. Further studies are needed to evaluate the development of muscular strength over a long period.

The impact of elective total hip and knee arthroplasty on physical performance in orthogeriatric patients: a prospective intervention study

BACKGROUND

Osteoarthritis is a prevalent condition in older adults that leads to reduced physical function in many patients and ultimately requires hip or knee replacement. The aim of the study was to determine the impact of hip and knee arthroplasty on the physical performance of orthogeriatric patients with osteoarthritis.

METHODS

In this prospective study, we used data from 135 participants of the ongoing Special Orthopaedic Geriatrics (SOG) trial, funded by the German Federal Joint Committee (GBA). Physical function, measured by the Short Physical Performance Battery (SPPB), was assessed preoperatively, 3 and 7 days postoperatively, 4-6 weeks and 3 months after hip and knee arthroplasty. For the statistical analysis, the Friedman test and post-hoc tests were used.

RESULTS

Of the 135 participants with a mean age of 78.5 ± 4.6 years, 81 underwent total hip arthroplasty and 54 total knee arthroplasty. In the total population, SPPB improved by a median of 2 points 3 months after joint replacement (p < 0.001). In the hip replacement group, SPPB increased by a median of 2 points 3 months after surgery (p < 0.001). At 3 months postoperatively, the SPPB increased by a median of 1 point in the knee replacement group (p = 0.003).

CONCLUSION

Elective total hip and knee arthroplasty leads to a clinically meaningful improvement in physical performance in orthogeriatric patients with osteoarthritis after only a few weeks.

TRIAL REGISTRATION

This study is part of the Special Orthopaedic Geriatrics (SOG) trial, German Clinical Trials Register DRKS00024102. Registered on 19 January 2021.

The Role and Efficiency of an AI-Powered Software in the Evaluation of Lower Limb Radiographs before and after Total Knee Arthroplasty

The rapid evolution of artificial intelligence (AI) in medical imaging analysis has significantly impacted musculoskeletal radiology, offering enhanced accuracy and speed in radiograph evaluations. The potential of AI in clinical settings, however, remains underexplored. This research investigates the efficiency of a commercial AI tool in analyzing radiographs of patients who have undergone total knee arthroplasty. The study retrospectively analyzed 200 radiographs from 100 patients, comparing AI software measurements to expert assessments. Assessed parameters included axial alignments (MAD, AMA), femoral and tibial angles (mLPFA, mLDFA, mMPTA, mLDTA), and other key measurements including JLCA, HKA, and Mikulicz line. The tool demonstrated good to excellent agreement with expert metrics (ICC = 0.78-1.00), analyzed radiographs twice as fast (p < 0.001), yet struggled with accuracy for the JLCA (ICC = 0.79, 95% CI = 0.72-0.84), the Mikulicz line (ICC = 0.78, 95% CI = 0.32-0.90), and if patients had a body mass index higher than 30 kg/m2 (p < 0.001). It also failed to analyze 45 (22.5%) radiographs, potentially due to image overlay or unique patient characteristics. These findings underscore the AI software's potential in musculoskeletal radiology but also highlight the necessity for further development for effective utilization in diverse clinical scenarios. Subsequent studies should explore the integration of AI tools in routine clinical practice and their impact on patient care.

Isokinetic knee muscle strength comparison after enhanced recovery after surgery (ERAS) versus conventional setup in total knee arthroplasty (TKA): a single blinded prospective randomized study

PURPOSE

Total knee arthroplasty (TKA) combined with the concept of enhanced recovery is of continued worldwide interest, as it is reported to improve early functional outcome and treatment quality without increasing complications. The aim of the study was to investigate isokinetic knee muscle strength after cemented TKA in combination with an enhanced recovery after surgery (ERAS) compared to a conventional setup.

METHODS

In the single blinded prospective randomized study, 52 patients underwent navigated primary cemented TKA within an ERAS (n = 30) or a conventional setup (n = 22). Preoperatively, five days and four weeks after surgery isokinetic knee muscle strength with BIODEX-type measuring device (peak torque in Nm, work in Joules and power in Watt) and subjective patient-related outcome measures (PROMs) were investigated.

RESULTS

The ERAS group showed significantly better outcomes in knee flexion at 180°/s (peak torque (Nm) p = 0.047, work (J) p = 0.040 and power (W) p = 0.016) 5 days postoperatively. The isokinetic measuring at knee extension 60°/s and 180°/s demonstrated no significant difference. The PROMs showed that patients were satisfied with the postoperative results in both groups. After 4 weeks, there was no longer a significant difference in isokinetic measuring at knee extension and flexion between the ERAS and conventional group.

CONCLUSIONS

TKA with the concept of ERAS improves excellent isokinetic outcome and patient satisfaction. The isokinetic muscle strength measurement can help patients and surgeons to modify expectations and improve patient satisfaction.

Total Knee Arthroplasty Violates the Law of Burmester-A Biomechanical Investigation

BACKGROUND

Kinematic patterns of knees after total knee arthroplasty (TKA) are different from those of healthy knees. We hypothesised that these changes cause a relevant shift in the medial and lateral epicondyles and, consequently, the insertion sites of the collateral ligaments. Any alterations, however, violate the law of Burmester, which states a close relation between the course of the collateral and cruciate ligaments, and the articular surfaces.

METHODS

Ten healthy knees of whole body cadavers were investigated. The positions of the medial and lateral epicondyles in relation to the tibia were compared before and after cruciate retaining fixed bearing TKA between 0 and 90° of flexion using a navigational device.

RESULTS

After TKA, the medial and lateral epicondyles significantly shifted laterally (~3-5mm) between 0° and 40° of flexion. Additionally, the lateral epicondyle was located significantly more dorsal (~3-5mm) during 0° and 20° of flexion and significantly shifted proximally (~2.5-3mm) between 0° and 30° of flexion.

CONCLUSIONS

By changing the epicondylar positions relative to the articular surfaces, the law of Burmester is violated in the present study setting. This might explain the impairment in motion, instability, or mid-flexion instability and the persistent pain in the knees after TKA.

Special orthopaedic geriatrics (SOG) - a new multiprofessional care model for elderly patients in elective orthopaedic surgery: a study protocol for a prospective randomized controlled trial of a multimodal intervention in frail patients with hip and knee replacement

BACKGROUND

Due to demographic change, the number of older people in Germany and worldwide will continue to rise in the coming decades. As a result, the number of elderly and frail patients undergoing total hip and knee arthroplasty is projected to increase significantly in the coming years. In order to reduce risk of complications and improve postoperative outcome, it can be beneficial to optimally prepare geriatric patients before orthopaedic surgery and to provide perioperative care by a multiprofessional orthogeriatric team. The aim of this comprehensive interventional study is to assess wether multimorbid patients can benefit from the new care model of special orthopaedic geriatrics (SOG) in elective total hip and knee arthroplasty.

METHODS

The SOG study is a registered, monocentric, prospective, randomized controlled trial (RCT) funded by the German Federal Joint Committee (GBA). This parallel group RCT with a total of 310 patients is intended to investigate the specially developed multimodal care model for orthogeriatric patients with total hip and knee arthroplasty (intervention group), which already begins preoperatively, in comparison to the usual orthopaedic care without orthogeriatric co-management (control group). Patients ≥70 years of age with multimorbidity or generally patients ≥80 years of age due to increased vulnerability with indication for elective primary total hip and knee arthroplasty can be included in the study. Exclusion criteria are age < 70 years, previous bony surgery or tumor in the area of the joint to be treated, infection and increased need for care (care level ≥ 4). The primary outcome is mobility measured by the Short Physical Performance Battery (SPPB). Secondary outcomes are morbidity, mortality, postoperative complications, delirium, cognition, mood, frailty, (instrumental) activities of daily living, malnutrition, pain, polypharmacy, and patient reported outcome measures. Tertiary outcomes are length of hospital stay, readmission rate, reoperation rate, transfusion rate, and time to rehabilitation. The study data will be collected preoperative, postoperative day 1 to 7, 4 to 6 weeks and 3 months after surgery.

DISCUSSION

Studies have shown that orthogeriatric co-management models in the treatment of hip fractures lead to significantly reduced morbidity and mortality rates. However, there are hardly any data available on the elective orthopaedic care of geriatric patients, especially in total hip and knee arthroplasty. In contrast to the care of trauma patients, optimal preoperative intervention is usually possible.

TRIAL REGISTRATION

German Clinical Trials Register DRKS00024102. Registered on 19 January 2021.

[Day-case outpatient endoprosthetics-"Ultra-Fast-Track"]

Fast-track procedures are common in general surgery today. In our European neighbour countries and in the USA, one-day-surgery for knee and hip replacement is gaining popularity. However, it is of great importance that a detailed concept for prehabilitation with a sufficient training program and targeted instructions regarding behavioral measures are established to allow a safe outpatient procedure. Where fast-track programs are established, one-day surgery with minimally invasive operative procedures for hip and knee arthroplasty is the consequent next step.

[Perioperative management in fast-track arthroplasty]

The optimization of organizational processes, as well as surgical procedures intra- and perioperatively, are essential components with respect to fast-track programs in clinical routine. Treatment concepts focus on early postoperative mobilization of patients after joint replacement surgery in an interdisciplinary setting to avoid pain and complications on a scientific basis. This article gives a comprehensive and detailed overview regarding evidence-based peri- and intraoperative fast-track treatment methods: from pain treatment with intraoperative local infiltration analgesia and tranexamic acid application under minimally invasive surgical approach in short-lasting spinal anesthesia to renunciation of drains, regional pain- and urinary catheters, tourniquets, and restrictions.

[Delirium-an interdisciplinary challenge]

BACKGROUND

Delirium is a common and potentially life-threatening disease that often poses major problems for hospitals in terms of care. It mainly affects older patients and is multifactorial, especially in older people. Permanent functional and cognitive impairments after delirium are not uncommon in geriatric patients.

DIAGNOSTIC

Often, delirious syndromes are not recognized or are misinterpreted. This is especially the case with the hypoactive form of delirium. Various screening and test procedures are available for the detection of delirium, the routine use of which is essential.

TREATMENT

In many cases, delirium can be avoided with suitable preventive measures. Above all, nondrug prevention strategies and multidimensional approaches play an important role here. For the drug treatment of delirium in geriatric patients, low-potency, classic and atypical neuroleptics, as well as dexmedetomidine for severe courses are recommended.

[Perioperative management of ortho-geriatric knee or hip arthroplasty patients]

Due to the changing age structure of the Western population, an increase in geriatric patients in endoprosthetic care of hip and knee joints is to be expected in the future. The age-related frailty and the existing comorbidities pose great challenges for the entire treatment team. In the preoperative phase, geriatric patients should be identified as such and adjustable risk factors should be addressed prior to surgery. The primary goals of treatment are to minimize trauma from anesthesia and endoprosthetic surgery to ensure immediate postoperative mobilization of patients. At the same time, any perioperative complications, especially intensive care treatments, should be prevented. This is achieved excellently with algorithms that are well known from fast-track surgery.

Differences in femoral component subsidence rate after THA using an uncemented collarless femoral stem: full weight-bearing with an enhanced recovery rehabilitation versus partial weight-bearing

BACKGROUND

Femoral component subsidence is a known risk factor for early failure of total hip arthroplasty (THA) using cementless stems. The aim of the study was to compare an enhanced recovery concept with early full weight-bearing rehabilitation and partial weight-bearing on stem subsidence. In addition, the influence of patient-related and anatomical risk factors on subsidence shall be assessed.

METHODS

One hundred and fourteen patients underwent primary cementless THA and were retrospectively analyzed. Sixty-three patients had an enhanced recovery rehabilitation with early full weight-bearing and 51 patients had rehabilitation with partial weight-bearing (20 kg) for 6 weeks. Postoperative subsidence was analyzed on standing pelvic anterior-posterior radiographs after 4 weeks and 1 year. Subsidence was measured in mm. Anatomical and prosthetic risk factors (stem size, canal flare index, canal fill ratio as well as BMI and demographic data) were correlated.

RESULTS

Femoral stem subsidence rate was significantly higher for the group with an enhanced recovery concept compared to the group with partial weight-bearing at the first radiological follow up after 4 weeks [2.54 mm (SD ± 1.86) vs. 1.55 mm (SD ± 1.80)] and the second radiological follow up after 1 year [3.43 mm (SD ± 2.24) vs. 1.94 (SD ± 2.16)] (p < 0.001, respectively). Stem angulation > 3° had a significant influence on subsidence. Canal flare index and canal fill ratio showed no significant correlation with subsidence as well as BMI and age.

CONCLUSION

In the present study, cementless stem subsidence was significantly higher in the group with enhanced recovery rehabilitation compared to partial weight-bearing. Small absolute values and differences were demonstrated and therefore possibly below clinical relevance. Anatomical radiological parameters and anthropometric data did not appear to be risk factors for stem subsidence.

Postoperative delirium is a risk factor for complications and poor outcome after total hip and knee arthroplasty

Background and purpose - Improving health care and demographic change have resulted in a steady increase in geriatric patients undergoing total hip (THA) and knee (TKA) arthroplasty. Postoperative delirium (POD) is a frequent and severe complication after major surgery. Therefore, we analyzed the impact of POD on outcome after THA and TKA.Patients and methods - In a consecutive series of 10,140 patients who had undergone elective THA or TKA between 2011 and 2020, rates of reoperation within 90 days, readmission within 90 days, complications, and responder rate as defined by the OMERACT-OARSI criteria were compared between patients with and without POD. Multivariable logistic regression models were used to assess the relationship between POD and other postoperative complications.Results - Patients with POD showed higher rates of reoperation (12% vs. 5%), readmission (15% vs. 5%), surgical complications (7% vs. 2%), non-surgical complications (8% vs. 4%), Clavien-Dindo IV° complications (10% vs. 2%) and transfusion (14% vs. 2%). POD led to lower responder rate (76% vs. 87%) 1 year after total joint replacement. All previous comparisons statistically significant. Multivariable logistic regression analyses revealed POD as an independent risk factor for reoperation (OR = 2; CI 1-3), readmission (OR = 2; CI 2-4) and Clavien-Dindo IV° complications (OR = 3; CI 2-5).Interpretation - POD is a serious problem in elective joint replacement. Affected patients suffer more complications and show poor patient-reported outcome 1 year postoperatively. Systematic prevention strategies and standardized therapy protocols are mandatory to avoid burden to patients and healthcare providers.

Superior Functional Outcome and Comparable Health-Related Quality of Life after Enhanced Recovery vs. Conventional THA: A Retrospective Matched Pair Analysis

BACKGROUND

The concept of enhanced recovery after total hip arthroplasty is gaining worldwide interest, as it shortens the length of hospital stay without an increase of complications. The aim of the study was to investigate the functional outcome and health-related quality of life 12 months after cementless total hip arthroplasty with the use of an enhanced recovery concept in comparison to a conventional rehabilitation.

MATERIAL AND METHODS

320 patients were retrospectively analyzed who underwent primary cementless total hip arthroplasty (THA). A total of 123 of the patients received an enhanced recovery program (ERAS) and 197 patients a conventional rehabilitation (Non-ERAS). Twelve months postoperatively, a clinical examination was performed regarding satisfaction, function and pain. Results were evaluated using WOMAC, EQ-5D-5L and EQ-VAS. A 1:1 matching was performed to correct for confounding variables, regarding age, sex and ASA score. Finally, 122 patients (n = 61, in each group) were analyzed and compared.

RESULTS

Patients showed a significant improvement of WOMAC total score, subscale pain, subscale stiffness and subscale function from preoperative to the follow up after 12 months in both groups, with significantly superior results for the WOMAC total score for the ERAS group (p = 0.042). EQ-5D and EQ-5D VAS showed a significant improvement from preoperative to 12 months postoperative (p < 0.001) for both groups, while no difference regarding the group-comparison was shown.

CONCLUSION

Health-related quality of life and functional outcome increased to excellent values after total hip arthroplasty with the use of an enhanced recovery concept and a conventional rehabilitation, with a superior WOMAC total score for ERAS and a tendency to better results for health-related quality of life for patients with ERAS within the follow up after 12 months.

Impact of malnutrition and vitamin deficiency in geriatric patients undergoing orthopedic surgery

Background and purpose - There is growing evidence that hypoproteinemia is an important risk factor for adverse events after surgery. Less is known about the impact of vitamin deficiency on postoperative outcome. Therefore we evaluated the prevalence and impact of malnutrition and vitamin deficiency in geriatric patients undergoing elective orthopedic surgery.Patients and methods - In a retrospective analysis of 599 geriatric patients who had undergone elective orthopedic surgery in 2018 and 2019, hypoproteinemia, and deficiency of vitamin D, vitamin B12, and folate were assessed. Reoperation rates, readmission rates, complication rates, and transfusion rates were compared between malnourished patients and patients with normal parameters. Multivariable logistic regression models were used to assess the relationship between malnutrition and postoperative adverse events, controlling for confounding factors such as age, sex, diabetes mellitus, and frailty.Results - Patients with malnutrition showed a higher rate of reoperation (13% vs. 5.5%; p = 0.01) and exhibited more wound-healing disorders (7.4% vs. 1.3%, p = 0.001) as well as Clavien-Dindo IV° complications (7.4% vs. 2.4%; p = 0.03). Deficiency of vitamin D led to a higher rate of falls (8.4% vs. 2.9%, p = 0.006). Deficiency of vitamin B12 and folate did not affect postoperative adverse events. Although correlated to frailty (p = 0.004), multivariable regression analysis identified malnutrition as independent risk factor for reoperation (OR 2.6, 95% CI 1.1-6.2) and wound healing disorders (OR 7.1, CI 1.9-26).Interpretation - Malnutrition is common among geriatric patients undergoing elective orthopedic surgery and represents an independent risk factor for postoperative adverse events.

Lower Limb Malrotation Is Regularly Present in Long-Leg Radiographs Resulting in Significant Measurement Errors

Weight-bearing long-leg radiographs are commonly used in orthopaedic surgery. Measured parameters, however, change when radiographs are conducted in different rotational positions of the leg. It was hypothesized that rotational errors are regularly present in long-leg radiographs resulting in wrong measurements. In 100 consecutive long-leg radiographs conducted according to the method of Paley, rotation was assessed by fibular overlap. Angular parameters in radiographs (mechanical lateral proximal femoral angle (mLPFA), mechanical lateral distal femoral angle (mLDFA), angle between the anatomical and mechanical femoral axis (AMA), mechanical medial proximal tibia angle (mMPTA), mechanical lateral distal tibial angle (mLDTA), and the mechanical femoral and tibial axis (mFA-mTA) were measured and deviations related to malrotation calculated. An average internal rotation of 8 degrees was found in lower limbs showing a range between 29 degrees of internal and 22 degrees of external rotation. As a result, mean differences before and after rotational correction for measured parameters (mLPFA, mLDFA, AMA, mMPTA, mLDTA, mFA-mTA) ranged between 0.4 and 1.7 degrees (-2.1; 5.6 95% confidence interval [CI]). In conclusion, malrotation of lower limbs is regularly present in long-leg radiographs. As all measured parameters are influenced by malrotation, correct lower limb rotation needs to be verified.

Pain management of unicompartmental (UKA) vs. total knee arthroplasty (TKA) based on a matched pair analysis of 4144 cases

Unicompartmental knee arthroplasty and total knee arthroplasty are well established treatment options for end-stage osteoarthritis, UKA still remains infrequently used if you take all knee arthroplasties into account. An important factor following knee arthroplasty is pain control in the perioperative experience, as high postoperative pain level is associated with persistent postsurgical pain. There is little literature which describes pain values and the need for pain medication following UKA and/or TKA. So far, no significant difference in pain has been found between UKA and TKA. The aim of the study was to evaluate differences in the postoperative course in unicompartmental knee arthroplasty vs. total knee arthroplasty regarding the need for pain medication and patient-reported outcomes including pain scores and side effects. We hypothesized that unicompartmental knee arthroplasty is superior to total knee arthroplasty in terms of postoperative pain values and the need of pain medication. In this project, we evaluated 2117 patients who had unicompartmental knee arthroplasty and 3798 who had total knee arthroplasty performed, from 2015 to 2018. A total of 4144 patients could be compared after performing the matched pair analysis. A professional team was used for data collection and short patient interviews to achieve high data quality on the first postoperative day. Parameters were compared after performing a 1:1 matched pair analysis, multicenter-wide in 14 orthopedic departments. Pain scores were significantly lower for the UKA group than those of the TKA group (p < 0.001 respectively for activity pain, minimum and maximum pain). In the recovery unit, there was less need for pain medication in patients with UKA (p = 0.004 for non-opioids). The opiate consumption was similarly lower for the UKA group, but not statistically significant (p = 0.15). In the ward, the UKA group needed less opioids (p < 0.001). Patient subjective parameters were significantly better for UKA. After implantation of unicompartmental knee arthroplasty, patients showed lower pain scores, a reduced need for pain medication and better patient subjective parameters in the early postoperative course in this study.

Matched-Pair Analysis of Local Infiltration Analgesia in Total Knee Arthroplasty: Patient Satisfaction and Perioperative Pain Management in 846 Cases

In the recent past, numerous studies evaluating local infiltration analgesia (LIA) with controversial results have been reported. Efforts have been made to improve patients' outcome regarding operation techniques and material, as well as pain management and anesthetic methods. In this study, postoperative pain management and patient satisfaction were evaluated in patients undergoing total knee replacement surgery with or without intraoperative LIA. Within the context of the "Quality Improvement in Postoperative Pain Management" (QUIPS) project, parameters were collected on the first postoperative day. All patients included in this study underwent primary knee replacement surgery with general anesthesia. Parameters were compared after performing a 1:1 matched-pair analysis within 14 orthopaedic departments. Pain levels and pain management satisfaction were measured using the numerous rating scales, and pain medication use was compared. From 2010 to 2015, 2,789 patients who underwent primary knee arthroplasty with general anesthesia were evaluated within the project, of whom a total of 846 patients could be compared after performing a matched-pair analysis. Pain scores were significantly better in the LIA group (p = 0.019 for activity pain, p = 0.043 for maximum pain, p < 0.001 for minimum pain), but pain management satisfaction was not superior (p = 0.083). Patients with LIA required less opioids in the recovery room (p = 0.048), while nonopioid medication did not differ significantly (p = 0.603). At the ward, 24 hours postoperatively, no significant difference in the use for nonopioids (p = 0.789) could be measured, whereas patients in the LIA group received significantly more opioids (p < 0.001). Although LIA achieved improvement in pain score outcome, and a comparable patient satisfaction level in the immediate postoperative course, the use of LIA in knee arthroplasty, controversially discussed in the current literature, was not able to reduce the need for opioid pain medication in this study.

Reproducibility of navigation based kinematic analysis of the knee - A cadaveric investigation

PURPOSE

Several navigation-based kinematic studies of the knee have been published recently, but little information is available about reproducibility and reliability of the acquired data. The aim of the present study first is to determine reproducibility and reliability of kinematical measurements of healthy knees and knees after TKA (total knee arthroplasty) with regards to rotational and translational measurement parameters. Second the mathematical background, applicability, and limitations of investigating navigation-based kinematics should be compiled.

METHODS

Using cadavers fixed by the Thiel method, in ten knees reproducibility of obtained angular and translational kinematic parameters were investigated before and after total knee arthroplasty. For this reason agreement of obtained data of a first and a second movement cycle and the same after a surgical intervention was assessed using a commercially available navigational device.

RESULTS

For both angular and translational parameters in healthy knees and knees after total knee arthroplasty mean differences between measured parameters of the first and second movement cycle and after surgical intervention of less than 0.5° or millimeters (standard deviation 1.3 or less) or a inter class correlation of 0.92 and more, respectively, was found.

DISCUSSION

Use of a commercial navigation system allows highly accurate investigations of knee kinematics in cadavers before and after TKA. This technique, which does not require any specific technical knowledge of the investigator, is in accordance with current accepted biomechanical methods.

Rotation of intramedullary alignment rods affects distal femoral cutting plane in total knee arthroplasty

PURPOSE

Intramedullary rods are widely used to align the distal femoral cut in total knee arthroplasty. We hypothesised that both coronal (varus/valgus) and sagittal (extension/flexion) cutting plane are affected by rotational changes of intramedullary femoral alignment guides.

METHODS

Distal femoral cuts using intramedullary alignment rods were simulated by means of a computer-aided engineering software in 4°, 6°, 8°, 10°, and 12° of valgus in relation to the femoral anatomical axis and 4° extension, neutral, as well as 4°, 8°, and 12° of flexion in relation to the femoral mechanical axis. This reflects the different angles between anatomical and mechanical axis in coronal and sagittal planes. To assess the influence of rotation of the alignment guide on the effective distal femoral cutting plane, all combinations were simulated with the rod gradually aligned from 40° of external to 40° of internal rotation.

RESULTS

Rotational changes of the distal femoral alignment guides affect both the coronal and sagittal cutting planes. When alignment rods are intruded neutrally with regards to sagittal alignment, external rotation causes flexion, while internal rotation causes extension of the sagittal cutting plane. Simultaneously the coronal effect (valgus) decreases resulting in an increased varus of the cutting plane. However, when alignment rods are intruded in extension or flexion partly contradictory effects are observed. Generally the effect increases with the degree of valgus preset, rotation and flexion.

CONCLUSION

As incorrect rotation of intramedullary alignment guides for distal femoral cuts causes significant cutting errors, exact rotational alignment is crucial. Coronal cutting errors in the distal femoral plane might result in overall leg malalignment, asymmetric extension gaps and subsequent sagittal cutting errors.

[Rheumatism operations in a state of flux-"Foot"]

Surgical management of rheumatic feet has dramatically changed over the last decades influenced by the development of new pharmacological drugs and tissue-preserving surgical procedures. It has switched from joint resection to joint-sparing procedures as the method of choice. Nevertheless, the surgical interventions commonly used for non-rheumatic patients cannot be applied to rheumatic patients without reflection: in addition to the basic treatment, comorbidities, degree of mobilization of the patient, orthopedic shoe engineering and orthotic treatment play a major role. Due to the decreasing incidence of the classical rheumatic foot, it has become even more important for physicians, physiotherapists and ergotherapists to recognize the development of such a disease as early as possible and immediately start the appropriate treatment.

Different Kinematics of Knees with Varus and Valgus Deformities

Few data exist of kinematics of knees with varus and valgus deformities combined with osteoarthritis. The purpose of this study was to reveal different (1) tibiofemoral kinematics, (2) medial and lateral gaps, and (3) condylar liftoff of osteoarthritic knees with either varus or valgus deformity before and after total knee arthroplasty (TKA). For this purpose, 40 patients for TKA were included in this study, 23 knees with varus deformity and 17 knees with valgus deformity. All patients underwent computer navigation, and kinematics was assessed before making any cuts or releases and after implantation. Osteoarthritic knees with valgus deformity showed a significant difference in tibia rotation relative to the femur with flexion before and after TKA, whereas knees with varus deformity did not. Knees with a valgus deformity showed femoral external rotation in extension and femoral internal rotation in flexion, whereas knees with a varus deformity revealed femoral internal rotation in extension and femoral external rotation in flexion. In both groups, gaps increased after TKA. Condylar liftoff was not observed in the varus deformity group after TKA. In the valgus deformity group, condylar liftoff was detected after TKA at knee flexion of 50 degrees and more. This study revealed significant differences in tibiofemoral kinematics between osteoarthritic knees with a varus or valgus deformity before and after TKA. Valgus deformities showed a paradoxic movement pattern. These in vivo intraoperative results need to be confirmed using fluoroscopic or radiographic three-dimensional matching before and after TKA.

What is the optimal valgus pre-set for intramedullary femoral alignment rods in total knee arthroplasty?

PURPOSE

In total knee arthroplasty (TKA), intramedullary guides are often used for aligning the distal femoral cutting block. Because of the highly varying angles between the mechanical axis and the anatomical femoral axis (AMA), different valgus pre-sets have been recommended. The present study investigated the optimal valgus pre-set (measuring the AMA in long-leg radiographs or at 5°, 6°, 7° or 8° valgus) to align the cutting block perpendicularly to the mechanical axis.

METHODS

The AMA was preoperatively measured in weight-bearing long-leg radiographs. After alignment of the cutting block by means of an intramedullary rod, deviation of the block from the mechanical femoral axis was measured with a pinless navigation device. The true AMA (tAMA) was calculated by adding the valgus pre-set of the alignment rod to the deviation measured with the navigation device. Mean deviations between the tAMA and (a) the AMA measured by the surgeon, (b) the AMA calculated with the computer software, (c) 5°, (d) 6°, (e) 7° and (f) 8° valgus pre-sets were measured for each patient. The lowest mean differences were determined.

RESULTS

The 40 knees measured showed a mean tAMA of 7.2° valgus (1.7 SD) (range 4°-11.5°). The following mean differences and 95 % limits of agreement were calculated: 2.2 (-1.2, 5.5) to the tAMA for the 5° valgus pre-set, 1.2 (-2.2, 4.5) for 6°, 0.2 (-3.2, 3.5) for 7° and -0.8 (-4.2, 2.5) for 8°. AMA measurements by the surgeon and with the digital medical planning software yielded mean differences of 0.6 (-3.1, 4.3) and 0.4 (-4.1, 4.8), respectively.

CONCLUSION

In the present setting, the best mean distal femoral cutting block alignment perpendicular to the mechanical femoral axis could be achieved with a valgus pre-set of 7° and not by measuring the AMA. Nevertheless, we recommend conducting weight-bearing radiographs of the entire leg prior to TKA for easy detection of any anatomical varieties, old fractures, long stems of total hip arthroplasties or cement. However, surgeons must be aware that exact coronal component alignment can only be achieved by navigational devices.

LEVEL OF EVIDENCE

Diagnostic study, Level II.

Postoperative pain and patient satisfaction are not influenced by daytime and duration of knee and hip arthroplasty: a prospective cohort study

PURPOSE

The number of total hip and knee arthroplasties (THA and TKA) is steadily increasing. Many factors that influence pain have been reported, but little is known about the correlation between the time of day and the duration of surgery and postoperative pain. On one hand, surgical interventions are performed faster due to economic pressure; on the other hand, obtaining sound surgical skills and a thorough education are most important for young surgeons, particularly at university hospitals. Amidst these different interests, it is the patient who should be the focus of all medical efforts. Therefore, our study investigated the effects of the time of day and the duration of total knee and hip arthroplasty on postoperative pain perception and patient satisfaction.

METHODS

623 patients were analyzed 24 h after primary total knee or hip arthroplasty regarding pain, patient satisfaction, and side effects by means of the questionnaires of the German-wide project Quality Improvement in Postoperative Pain Management (QUIPS).

RESULTS

The time of day and the duration of knee or hip arthroplasty were not correlated with maximum, minimum, and activity-related pain and patient satisfaction rated on a numeric rating scale (NRS).

CONCLUSIONS

This study is the first to show that neither the time of day nor the duration of surgery has any influence on patient satisfaction and postoperative pain 24 h after total knee or hip arthroplasty; regarding these aspects, young orthopaedic surgeons may be trained in the operating theatre without time pressure.

The influence of varus and valgus deviation on patellar kinematics in healthy knees: An exploratory cadaver study

BACKGROUND

Patellofemoral instability may lead to osteoarthritis, anterior knee pain, and patellar luxation. The purpose of this study was to conduct an exploratory investigation into the difference of patellar kinematics of healthy knees during extension/flexion cycles in neutral, varus and valgus alignment.

METHODS

The three-dimensional patellar kinematics of 10 lower extremities of whole body cadavers were examined during passive motion, in neutral position, and under valgus and varus stress. Kinematics was recorded by means of an optical computer navigation system.

RESULTS

The study samples did not significantly differ with regard to mediolateral patellar shift and epicondylar distance. Varus stress led to significantly higher external rotation than valgus stress (P=0.04) and to a significantly higher lateral patellar tilt than neutral position (P=0.016) and valgus stress (P=0.016). No difference was found between valgus stress and neutral position.

CONCLUSION

Analysis of tibiofemoral alignment alone is insufficient for predicting patellar kinematics.

Positive medium-term influence of multimodal pain management on socioeconomic factors and health care utilization in patients with lumbar radiculopathy: a prospective study

Background

Multimodal pain management (MPM) represents a central approach to avoiding surgery in patients with lumbar radiculopathy. Independent of the type of health system, cost effectiveness and socioeconomic factors are becoming increasingly important. This study investigated the medium-term influence of conservative MPM on health care utilization and socioeconomic factors.

Methods

This study compared subjective, objective, and socioeconomic factors of 60 patients after inpatient MPM because of lumbar radiculopathy, before and 1 year ± 2 weeks after treatment.

Results

Over the course of the 1-year follow-up, one-third of the patients had not required any conservative treatment in comparison to 100% of patients before MPM therapy. The number of patients requiring analgesics could be significantly reduced from 26 to 12, and the number of patients who did not require any analgesics had increased from 14 to 32. After 1 year, the number of patients who had to regularly contact a physician because of low back pain (once per month for 6 months) had been reduced from 58 to 27.

Conclusion

MPM is an effective approach to treating lumbar radiculopathy and reducing its negative influence on socioeconomic factors. Therapeutic benefits also include a decrease in health care utilization. Therefore, health care providers should place the mid-term success for patients and socioeconomic factors before the short-term costs of therapy.

Presence of rotational errors in long leg radiographs after total knee arthroplasty and impact on measured lower limb and component alignment

PURPOSE

Rotation of the lower limb in weight bearing long leg radiographs has a great impact on measured component and lower limb alignment parameters. We asked which rotational errors of long leg radiographs are present in a high volume centre and which radiological and clinical consequences arise regarding measured coronal component and lower limb alignment after total knee arthroplasty.

METHODS

In 100 long leg radiographs coronal femoral and tibial component alignment and hip knee ankle angle (HKA) were measured. Present rotational errors in long leg radiographs were determined by fibular overlap and its impact on alignment parameters calculated.

RESULTS

A mean internal rotation of 8.1° (9.3 SD) with a range between 36° of internal and 16° of external rotation was found in long leg radiographs. This resulted in mean differences between measurements before and after rotational correction regarding femoral and tibial component alignment and HKA of 0.6-0.8° (range 3.5° valgus and 1.6° varus error). Clinically, 11 out of 100 patients were wrongly assigned to either mal- or well-alignment (neutral mechanical alignment within ±3° varus or valgus).

CONCLUSION

Surgeons should be aware of potential rotational errors in long leg radiographs after total knee arthroplasty resulting in wrong measurements. In case of rotational errors, radiographs should be repeated or rotational corrections calculated. For study purposes only radiographs after rotational correction should be accepted.

Significant influence of rotational limb alignment parameters on patellar kinematics: an in vitro study

PURPOSE

Component malrotation has a major impact on patellar kinematics in total knee arthroplasty. The influence of natural rotational limb alignment on patellar kinematics is unclear so far. Based on recent clinical investigations, we hypothesized that rotational limb alignment significantly influences patellar kinematics.

METHODS

Patellar kinematics of ten cadaveric knees was measured using computer navigation during passive motion. Data were correlated with different rotational limb alignment parameters of preoperative CT scans.

RESULTS

Femoral antetorsion showed a significant influence on patellar rotation, while tibial tubercle-posterior cruciate ligament distance additionally displayed a significant influence on patellar mediolateral shift (p < 0.05). Femoral posterior condylar angle was sensitive to patellar epicondylar distance, rotation and tilt (p < 0.05). Patellar rotation was influenced by five out of eight rotational limb alignment parameters (p < 0.05).

CONCLUSIONS

Rotational limb alignment should be paid more attention in terms of clinical evaluation of patellar tracking and future biomechanical and clinical investigations.

[Patella navigation in computer-assisted TKA : Intraoperative measurement of patellar kinematics. Video article]

INTRODUCTION

Patellofemoral maltracking is a relevant problem after total knee arthroplasty (TKA). Patella navigation is a tool that allows real time monitoring of patella tracking.

MATERIAL

This video contribution demonstrates the technique of patellofemoral navigation and a possible consequence of intraoperative monitoring. A higher postoperative lateral tilt is addressed with a widening of the lateral retinaculum in a particular manner.

CONCLUSION

In selected cases of patellofemoral problems, patella navigation is a helpful tool to evaluate patellofemoral tracking intraoperatively. Modifications of implant position and soft tissue measurements can then prevent postoperative patellofemoral maltracking.

Changes in sagittal component alignment alters patellar kinematics in TKA: an in vitro study

PURPOSE

Patellar maltracking due to incorrect component alignment is considered as a main reason for anterior knee pain after total knee arthroplasty (TKA). In contrast to coronal and axial component placement, the influence of sagittal component alignment on patellar kinematics has not been investigated so far.

METHODS

In ten lower cadaveric limbs, TKAs were implanted using a commercial computer navigation system. In six knees, the femoral component was aligned in 5° and in four knees in 0° of flexion, respectively. Patellar kinematics were registered by means of a computer navigation system using an additional patella tracking array and correlated with femoral and tibial sagittal component alignment.

RESULTS

Sagittal component alignment significantly altered patellar mediolateral shift (p < 0.05). In contrast, patellar epicondylar distance, rotation and tilt were not significantly influenced.

CONCLUSIONS

Sagittal component alignment in TKA has a major impact on patellar kinematics and should therefore be considered while addressing tibiofemoral kinematics intraoperatively.

[Operative therapy for rheumatoid arthritis of the hand]

The need for operative treatment of severe rheumatic deformities of the hand and wrist is decreasing due to the increased use of disease-modifying drugs; however, some patients do not tolerate or do not sufficiently respond to these drugs, which often results in the hands being affected and in advanced stages to severe deformity and loss of function. In these cases operative surgery can help to slow the progression of rheumatic destruction and restore the function of the patient's hand. This article describes the principles of surgery for rheumatoid arthritis of the hand. A meticulous synovectomy or tenosynovectomy is the first stage of treatment. With progression of rheumatic destruction various salvage procedures are necessary to preserve the best possible functional state.

Difference in periprosthetic acetabular bone mineral density: Prior total hip arthroplasty: Osteonecrosis of the femoral head versus primary osteoarthritis

BACKGROUND

Total hip arthroplasty (THA) could be associated with a higher failure rate in patients after osteonecrosis of the femoral head (ONFH) compared to a patient population with primary osteoarthritis prior THA, especially regarding the acetabular component. One major reason could be the compromised acetabular bone quality. Therefore, we performed a retrospective case matched study to assess: 1) Is there a difference in periprosthetic bone mineral density between patients with an ONFH prior THA and controls? 2) Do patients with an ONFH prior THA have a lower bone mineral density compared to controls? 3) Which region in the periprosthetic bone stock is more likely to present differences in periprosthetic bone mineral density between both groups?

HYPOTHESIS

We hypothesized that there is a poorer bone mineral density (BMD) in the periacetabular bone stock in patients with an ONFH prior THA compared to controls receiving a THA due to primary osteoarthritis.

PATIENTS AND METHODS

We compared the BMD of 50 patients with ONFH to 50 controls with primary osteoarthritis prior THA using the same implant in mean 5 years after surgery by means of dual energy X-ray absorptiometry (DXA). We analysed 3 acetabular ROIs according to DeLee and Charnley in a modified measurement technique.

RESULTS

In ROI 3, representing acetabulum's upper aspect, statistically significant lower BMD values for the ONFH group could be found (P < 0.05). No difference was found for the modified ROIs 1 and 2 (respectively medial and lower acetabulum).

DISCUSSION

The results indicate a poorer periacetabular BMD in patients with ONFH prior THA, which might be responsible for premature loosening of the acetabular cup in THA. Due to a lack of literature, further clinical investigations are required to confirm our results.

LEVEL OF EVIDENCE

III: retrospective case-control study.

Assessing joint line positions by means of the contralateral knee: a new approach for planning knee revision surgery?

PURPOSE

Reconstructing the natural joint line in knee revision surgery improves clinical and functional outcome but may be challenging when both cartilage and bone were removed during previous operations. Assessing joint lines (JLs) by means of bony landmarks is inadvisable because of large variations in human anatomy. Because of the inherent symmetry of the human body, we hypothesised that JLs may be directly assessed by measuring the distances from the bony landmarks to the JL of the contralateral knee by means of radiographic images.

METHODS

Using scaled weight-bearing radiographs in anteroposterior view of both knees, two independent observers measured the distances from the fibular head, the medial and lateral epicondyle, and the adductor tubercle to the JL. A two-sided p value of ≤0.05 was considered statistically significant.

RESULTS

Two hundred knees of 100 patients (50 men and 50 women) were examined. For the fibular head, the mean difference between the treated and the control knee was 0.0 mm with narrow confidence limits ranging from -1.1 to 1.1.

CONCLUSION

As a new assessment method, we have suggested to assess the JL by means of radiographs of the contralateral knee. The most precise parameter was found to be the distance between the fibular head and the JL. The level of arthritis, age, gender, visibility of the landmarks, and misalignment did not influence measurement accuracy. This parameter is the first tibia-related landmark for assessing the JL, which advantageously corresponds to the tibia-first technique in revision surgery.

LEVEL OF EVIDENCE

Diagnostic Study, Level II.

[Clinical examination of the hip joint in adults]

Complaints in the region of the hips and pelvis are often difficult to classify. This is due to the fact that pain projection and overlapping can occur; therefore, the complete region of the lumbar spine, pelvis and hips must be considered as a single entity in which alterations can result in radiation throughout the whole region. There are many different anatomical structures within the pelvic region so that the function of various muscle components can be impaired and cause pathological alterations to positional relationships of bony structures or even alterations to other soft tissues, such as ligaments, tendons and labra. In terms of differential diagnostics the groin must be seen as the weak point of the peritoneum and vascular system and taken into consideration. Therefore, a detailed and targeted medical history, functional testing and specific examinations and tests are necessary to narrow down the pathology in question and reach a definitive diagnosis. Orthopedic surgeons must know which conspicuous features can lead to which problems and which anatomical structures are likely to be affected by irritation. The results of the clinical examination are the basis for targeted imaging diagnostics and subsequent therapy.

The influence of component alignment on patellar kinematics in total knee arthroplasty

BACKGROUND AND PURPOSE

Postoperative anterior knee pain is one of the most frequent complications after total knee arthroplasty (TKA). Changes in patellar kinematics after TKA relative to the preoperative arthritic knee are not well understood. We compared the patellar kinematics preoperatively with the kinematics after ligament-balanced navigated TKA.

PATIENTS AND METHODS

We measured patellar tracking before and after ligament-balanced TKA in 40 consecutive patients using computer navigation. Furthermore, the influences of different femoral and tibial component alignment on patellar kinematics were analyzed using generalized linear models.

RESULTS

After TKA, the patellae shifted statistically significantly more laterally between 30° and 60°. The lateral tilt increased at 90° of flexion whereas the epicondylar distance decreased between 45° and 75° of flexion. Sagittal component alignment, but not rotational component alignment, had a significant influence on patellar kinematics.

INTERPRETATION

There are major differences in patellar kinematics between the preoperative arthritic knee and the knee after TKA. Combined sagittal component alignment in particular appears to have a major effect on patellar kinematics. Surgeons should be especially aware of altering preoperative sagittal alignment until the possible clinical relevance has been investigated.

[Clinical examination of the hip joint in adults]

Complaints in the region of the hips and pelvis are often difficult to classify. This is due to the fact that pain projection and overlapping can occur; therefore, the complete region of the lumbar spine, pelvis and hips must be considered as a single entity in which alterations can result in radiation throughout the whole region. There are many different anatomical structures within the pelvic region so that the function of various muscle components can be impaired and cause pathological alterations to positional relationships of bony structures or even alterations to other soft tissues, such as ligaments, tendons and labra. In terms of differential diagnostics the groin must be seen as the weak point of the peritoneum and vascular system and taken into consideration. Therefore, a detailed and targeted medical history, functional testing and specific examinations and tests are necessary to narrow down the pathology in question and reach a definitive diagnosis. Orthopedic surgeons must know which conspicuous features can lead to which problems and which anatomical structures are likely to be affected by irritation. The results of the clinical examination are the basis for targeted imaging diagnostics and subsequent therapy.

No difference between standard and high flexion cruciate retaining total knee arthroplasty: a prospective randomised controlled study

PURPOSE

The purpose of this prospective, randomised, double-blind study was to test the hypotheses that patients with high-flexion total knee arthroplasty (TKA) have (1) a wider/greater range of motion (ROM) post-operatively and (2) higher levels of knee society score (KSS) and WOMAC score post-operatively compared to standard TKA.

METHODS

In this study, 28 high flexion with 31 standard TKAs were compared. We measured ROM, pre-operatively, on day 3, 7, 28, and after 6 and 36 months post-operatively as well as KSS and WOMAC score pre-operatively, on day 28 and after 6 and 36 months post-operatively.

RESULTS

No statistically significant differences were found between both groups with regard to the target parameters. The mean ROM was 113° (range 80°-140°, SD 13.4°) in the control group (standard TKA) and 117° (range 90°-140°, SD 12.3) in the study group (high-flexion TKA) at 36 months follow-up [p = not significant (n.s.)]. The KSS pre-operatively was 38.2 (range 8-64, SD 15.8) in the control group and 45.9 (range 8-74, SD 16.0) in the study group (n.s.) increasing to 157.6 in the control group and 156.7 in the study group (p = n.s) at 36 months follow-up.

CONCLUSION

This study could not confirm significant benefits of high-flexion TKA compared to standard TKA with regard to ROM and higher levels of KSS and WOMAC score.

LEVEL OF EVIDENCE

I.

[Prevention of periprosthetic joint infections : Not evidence-based strategies]

BACKGROUND

Surgical site infections are the most common nosocomial infections in orthopedic surgery. Strategies to prevent these infections are of enormous relevance.

OBJECTIVES

Evidence-based procedures such as hand disinfection, prophylactic antibiotic application, hair removal with electric clippers, or preoperative treatment of Staphyloccus aureus are listed in national and international guidelines. Beside these measures, several scientifically not confirmed methods, e.g., the administration of antibiotic prophylaxis for several days or the usage of helmets during surgery, are still practiced. These measures are not evidence-based and should not be performed anymore.

CONCLUSION

Only the consequent implementation of evidence-based procedures can help prevent surgical site infections.

[Wrist arthroscopy : challenging procedure of modern hand surgery]

Arthroscopy of the wrist has developed in the shadow of arthroscopy of the large joints. Nowadays, wrist arthroscopy has a relevant importance in the diagnostics and therapy in hand surgery and is indispensable for serious surgery of the wrist. Special equipment and extensive knowledge of the surgeon are necessary for carrying out the procedure.

Predicting knee rotation by the projection overlap of the proximal fibula and tibia in long-leg radiographs

PURPOSE

Rotation of the lower limbs in long-leg radiographs has a significant impact on imaging the mechanical femorotibial angle, the femoral anatomic mechanical angle, the mechanical lateral distal femoral angle (mLDFA) and the mechanical medial proximal tibial angle (mMPTA). In this study, we assessed the rotation of the lower limbs in conventional radiographs and hypothesized that the relative position of the proximal fibula to the proximal tibia on long-leg radiographs is related to the rotation of the knee joint.

METHODS

Radiological examinations in different rotational positions of the knee joint (incremental 40° internal to 40° external rotation) were imitated by 50 computed tomography scans (50 patients, 25 men and 25 women). The extent of the projection overlaps of the fibula, the fibular tip and the distance from the fibular tip to the lateral cortex were determined for every rotational position.

RESULTS

Multiple regression analysis showed a very strong correlation between the measured fibular parameters and knee rotation between 20° of internal rotation and 40° of external rotation (R (2) ~ 0.94, p < 0.001). By means of these results, we created a formula for predicting knee rotation: [Formula: see text]This strong correlation could not be found between 20° and 40° of internal rotation.

DISCUSSION

Because incorrect internal and external rotation negatively influence the correct measurement of angles (mechanical femorotibial angle, femoral anatomic mechanical angle, the mLDFA and the mMPTA), long-leg radiographs should be assessed for proper rotation angles before measurement. Using the provided formula rotation of the lower limb in weight-bearing, long-leg radiographs can be reliably predicted.

LEVEL OF EVIDENCE

Diagnostic study, Level II.