[Trends in navigation-handheld systems]. / Trends in der Navigation ­ Handheld-Systeme.

Navigation-assisted surgical procedures in orthopedics and trauma surgery have become increasingly widespread over the last 20 years. In addition to applications in spinal surgery, they are primarily available for knee and hip endoprosthetics. On the one hand, computer-assisted procedures have been increasingly expanded with robotic assistance systems in recent years, and on the other hand, so-called handheld navigation systems have been developed, which enable specialized use directly in the operating field at lower acquisition costs. The aim of this overview is to describe current handheld systems and to present the respective technical principles and the available scientific results. Three handheld systems for TKA use, two for THA use and one system to support pedicle screw placement on the spine are presented.

Significant correlations between postoperative outcomes and various limb and component alignment strategies in medial unicompartmental knee arthroplasty: a systematic review.

PURPOSE: To investigate the correlation between postoperative limb/component alignments and clinical/functional outcomes following medial unicondylar knee arthroplasty (mUKA). METHODS: Inclusion criteria included peer-reviewed English- or German-language publications assessing postoperative limb or implant alignment and clinical outcomes of mUKA. Methodological Index for Non-Randomized Studies (MINORS) was used to assess article quality. RESULTS: A total of 2767 knees from 2604 patients were evaluated. Significant correlations were observed between postoperative limb/component alignments and clinical/functional outcomes after mUKA. Inferior outcomes were associated with lower placement and excessive valgus alignment of the tibia component (> 3°). A recommended external rotation of 4°-5° was identified for the tibia component, with specific cut-off values for the femoral and tibia components. CONCLUSIONS: Optimal outcomes in mUKA were associated with a varus coronal limb alignment. The tibia implant component performed well within a specific alignment range. An exact external rotation value was recommended for the tibia component, while internal rotation correlated negatively with the femoral component. LEVEL OF EVIDENCE: IV (level IV retrospective case series were included).

Improved Knee Function with Customized vs. Off-the-Shelf TKA Implants-Results of a Single-Surgeon, Single-Center, Single-Blinded Study.

BACKGROUND: Recent studies have been able to show certain benefits of Customized, Individually Made (CIM) compared to Off-the-Shelf (OTS) total knee arthroplasties (TKAs), but evidence is still lacking regarding the benefits of these implant systems. This study aimed to find differences in scores and functional outcome by comparing CIM and OTS implants, using Patient-Reported Outcome Measures (PROMs) and functional tests for activities of daily living in a single-surgeon setup. METHODS: A total of 48 patients (16 CIM vs. 32 OTS) were consecutively enrolled and blindly examined. Functional testing was performed using four timed functional tests (TUG, WALK, TUDS, and BBS) and the VAS for pain. The Aggregated Locomotor Function (ALF) score was then calculated based on the addition of the average times of the three functional tests. RESULTS: The CIM group showed significantly faster times in all functional tests and significantly better ALF scores. There were remarkable differences in the assessment of maximum pain sensation between the two groups, with superiority in the CIM group. The PROMs analysis revealed a higher proportion of excellent and good ratings for the items objective and function (KSS) in the CIM group. CONCLUSION: The study showed that time-limited activities of daily living (ADLs) can be completed significantly faster with a CIM prosthesis and that a significantly higher percentage in this group reports freedom from pain during certain loads. Partial aspects of the PROM scores are also better in this group; however, this superiority could not be shown with regard to most PROM scores collected in this study.

Pharmatherapeutic Treatment of Osteoarthrosis-Does the Pill against Already Exist? A Narrative Review.

The aim of this narrative review is to summarize the current pharmacotherapeutic treatment options for osteoarthritis (OA). Is therapy still mainly symptomatic or does the pill against arthrosis already exist? Causal and non-causal, as well as future therapeutic approaches, are discussed. Various surgical and non-surgical treatment options are available that can help manage symptoms, slow down progression, and improve quality of life. To date, however, therapy is still mainly symptomatic, often using painkilling and anti-inflammatory drugs until the final stage, which is usually joint replacement. These "symptomatic pills against" have side effects and do not alter the progression of OA, which is caused by an imbalance between degenerative and regenerative processes. Next to resolving mechanical issues, the goal must be to gain a better understanding of the cellular and molecular basis of OA. Recently, there has been a lot of interest in cartilage-regenerative medicine and in the current style of treating rheumatoid arthritis, where drug therapy ("the pill against") has been established to slow down or even stop the progression of rheumatoid arthritis and has banned the vast majority of former almost regular severe joint destructions. However, the "causal pill against" OA does not exist so far. First, the early detection of osteoarthritis by means of biomarkers and imaging should therefore gain more focus. Second, future therapeutic approaches have to identify innovative therapeutic approaches influencing inflammatory and metabolic processes. Several pharmacologic, genetic, and even epigenetic attempts are promising, but none have clinically improved causal therapy so far, unfortunately.

Associations of preoperative anemia and postoperative hemoglobin values with hospital costs in total knee arthroplasty (TKA).

BACKGROUND: Total knee arthroplasty are among the most frequently conducted surgeries, due to an aging society. Since hospital costs are subsequently rising, adequate preparation of patients and reimbursement becomes more and more important. Recent literature revealed anemia as a risk factor for enhanced length of stay (LOS) and complications. This study analyzed whether preoperative hemoglobin (Hb) and postoperative Hb were associated with total hospital costs and general ward costs. METHODS: The study comprised 367 patients from a single high-volume hospital in Germany. Hospital costs were calculated with standardized cost accounting methods. Generalized linear models were applied to account for confounders, such as age, comorbidities, body mass index, insurance status, health-related quality of life, implant types, incision-suture-time and tranexamic acid. RESULTS: Preoperative anemic women had 426 Euros higher general ward costs (p < 0.01), due to increased LOS. For men, 1 g/dl less Hb loss between the preoperative value and the value before discharge reduced total costs by 292 Euros (p < 0.001) and 161 Euros fewer general ward costs (p < 0.001). Total hospital costs were reduced by 144 Euros with 1 g/dl higher Hb on day 2 postoperatively for women (p < 0.01). CONCLUSION: Preoperative anemia was associated with increased general ward costs for women and Hb loss with decreasing total hospital costs for men and women. Cost containment, especially reduced utilization of the general ward, may be feasible with the correction of anemia for women. Postoperative Hb values may be a factor for adjustments of reimbursement systems. LEVEL OF EVIDENCE: Retrospective cohort study, III.

The impact of primary patella resurfacing on health-related quality of life outcomes and return to sport in total knee arthroplasty (TKA).

INTRODUCTION: Primary patella resurfacing (PPR) in primary total knee arthroplasty (TKA) is a topic without clear clinical evidence. Using Patient Reported Outcome Measurements (PROM), previous work found TKA patients without PPR to have more pain postoperatively, but little is known whether this may impede patients from returning to their usual leisure sport. This observational study aimed at evaluating the treatment effect of PPR, with PROMs and return to sport (RTS). MATERIALS AND METHODS: 156 primary TKA patients were retrospectively included from August 2019 to November 2020, from a single hospital in Germany. PROMs were measured with the Western Ontario McMaster University Osteoarthritis Index (WOMAC) and the EuroQoL Visual Analog Scale (EQ-VAS), preoperatively and 1 year postoperatively. Leisure sport with three levels of intensity (never, sometimes, regular) were requested. The treatment effect of PPR was evaluated with a difference-in-difference (DiD) approach, with several confounders. RESULTS: Descriptively, the mean WOMAC total score and the mean WOMAC pain score were postoperatively better with PPR, ( - 4.8 points, - 1.1 points), then without PPR. The mean improvements of the WOMAC total score were better with PPR ( - 7.8 points). Mean improvements for the WOMAC pain score were also better with PPR ( - 1.2 points). Mean EQ-VAS were postoperatively similar, and the mean improvements were better with PPR (3.4 points). Rate of RTS was 93% for patients with PPR and 95% for patients without PPR. The DiD revealed minor differences in PROMs and RTS, not to result in statistically significant treatment effects. CONCLUSIONS: There was no treatment effect for TKA with PPR, regarding PROMs and RTS, and descriptive differences were below published thresholds for clinical relevance. Rate of RTS was high for all patients, regardless of PPR. For the two endpoint categories, there was no measurable advantage of TKA with PPR over TKA without PPR.

High degree of consensus amongst an expert panel regarding focal resurfacing of chondral and osteochondral lesions of the femur with mini-implants.

INTRODUCTION: The rationale for the use of mini-implants for partial resurfacing in the treatment of femoral chondral and osteochondral lesions is still under debate. The evidence supporting best practise guidelines is based on studies with low-level evidence. A consensus group of experts was convened to collaboratively advance towards consensus opinions regarding the best available evidence. The purpose of this article is to report the resulting consensus statements. METHODS: Twenty-five experts participated in a process based on the Delphi method of achieving consensus. Questions and statements were drafted via an online survey of two rounds, for initial agreement and comments on the proposed statements. An in-person meeting between the panellists was organised during the 2022 ESSKA congress to further discuss and debate each of the statements. A final agreement was made via a final online survey a few days later. The strength of consensus was characterised as: consensus, 51-74% agreement; strong consensus, 75-99% agreement; unanimous, 100% agreement. RESULTS: Statements were developed in the fields of patient assessment and indications, surgical considerations and postoperative care. Between the 25 statements that were discussed by this working group, 18 achieved unanimous, whilst 7 strong consensus. CONCLUSION: The consensus statements, derived from experts in the field, represent guidelines to assist clinicians in decision-making for the appropriate use of mini-implants for partial resurfacing in the treatment of femoral chondral and osteochondral lesions. LEVEL OF EVIDENCE: Level V.

Patient Specific Instruments and Patient Individual Implants-A Narrative Review.

Joint arthroplasties are one of the most frequently performed standard operations worldwide. Patient individual instruments and patient individual implants represent an innovation that must prove its usefulness in further studies. However, promising results are emerging. Those implants seem to be a benefit especially in revision situations. Most experience is available in the field of knee and hip arthroplasty. Patient-specific instruments for the shoulder and upper ankle are much less common. Patient individual implants combine individual cutting blocks and implants, while patient individual instruments solely use individual cutting blocks in combination with off-the-shelf implants. This review summarizes the current data regarding the implantation of individual implants and the use of individual instruments.

Cutting-Edge Approaches in Arthroplasty: Before, during and after Surgery.

Personalised medicine was introduced in arthroplasty a long time ago with the aim of respecting each individual person for their unique personal characteristics in order to further improve outcomes [...].

[When nothing else works: patellofemoral joint arthroplasty]. / Wenn nichts mehr geht: Der patellofemorale Gelenkersatz.

Patellofemoral joint replacement is the best treatment option available for isolated patellofemoral arthritis. Especially young patients should be operated on with bone-sparing techniques that also preserve the soft tissues, since these patients are very likely to be revised at some point in their lifetime. Correct patient selection is important for the success of surgery and should include a meticulous clinical examination and imaging. Special attention should be paid to additional pathologies that may also need to be addressed. For the trochlea, there are two different options for treatment with the inlay and onlay system. The retropatellar surface should be replaced. Patellofemoral joint replacement is still rarely performed, so treatment in specialised centres is recommended. National joint registry data show high revision rates, while data from centres show promising results.

Contemporary knee arthroplasty: one fits all or time for diversity?

INTRODUCTION: Total knee arthroplasty (TKA) has historically been the preferred solution for any type of knee osteoarthritis, independently of the number of compartments involved. In these days of patient-specific medicine, mono-compartmental disease could also be approached with a more individualized treatment, such as partial knee arthroplasty (PKA). Off-the-shelf (OTS) implants are often the compromise of averages and means of a limited series of anatomical parameters retrieved from patients and the pressure of cost control by limited inventory. Personalized medicine requires respect and interest for the individual shape and alignment of each patient. MATERIALS AND METHODS: A Pubmed and Google Scholar search were performed with the following terms: "patient-specific knee" and "arthroplasty" and "custom implant" and "total knee replacement" and "partial knee replacement" and "patellofemoral knee replacement" and "bicompartmental knee replacement". The full text of 90 articles was used to write this narrative review. RESULTS: Unicondylar, patellofemoral and bicompartmental knee arthroplasty are successful treatment options, which can be considered over TKA for their bone and ligament sparing character and the superior functional outcome that can be obtained with resurfacing procedures. For TKA, where compromises dominate our choices, especially in patients with individual variations of their personal anatomy outside of the standard, a customized implant could be a preferable solution. CONCLUSION: TKA might not be the only solution for every patient with knee osteoarthritis, if personalized medicine wants to be offered. Patient-specific mono-compartmental resurfacing solutions, such as partial knee arthroplasty, can be part of the treatment options proposed by the expert surgeon. Customized implants and personalized alignment options have the potential to further improve clinical outcome by identifying the individual morphotype and respecting the diversity of the surgical population.

[New technologies (robotics, custom-made) in unicondylar knee arthroplasty-pro]. / Neue Technologien (Robotik, "custom made") in der unikondylären Endoprothetik ­ Pro.

BACKGROUND: Unicondylar knee arthroplasty offers the advantage that partial degenerative changes can be addressed with partial prosthetic solutions, thus preserving as much of the native joint as possible, including the cruciate ligaments. On the other hand, the number of revisions is still higher than for total knee endoprosthetics. In the literature, the causes mentioned are insufficient fit of the components as well as surgical errors. The use of new technologies to achieve a better fit and higher surgical precision and reproducibility, therefore, represents a promising approach. INDIVIDUAL ENDOPROSTHETICS: Individual endoprosthetics offers the advantage that the prosthesis is adapted to the individual anatomy of each patient and not the patient's anatomy to the prosthesis, as is the case with standard prostheses. This allows for an optimal fit of the prosthesis while avoiding excessive bone resections and soft tissue releases. ROBOTICS: The use of robotics in endoprosthetics makes it easier to correctly perform bone resections and align components. This ensures high and reproducible precision even for surgeons with lower case numbers. Studies on individual unicondylar endoprosthetics and robotics are reporting promising results. However, long-term results of high-quality randomized studies must be awaited in order to make a scientifically sound statement.

Unicondylar Tibiofemoral Arthroplasty - Opinions of the Members of the German Knee Society (DKG) and the German Professional Association of Orthopaedic and Trauma Specialists (BVOU). / Unikondyläre tibiofemorale Endoprothetik ­ Meinungsbild in der Deutschen Kniegesellschaft (DKG) und dem Bundesverband der Orthopäden und Unfallchirurgen (BVOU).

BACKGROUND: The number of implanted unicondylar tibiofemoral knee arthroplasties (UKA) is despite the potential advantages in comparison to total knee arthroplasties (TKA) in Germany relatively low. Goal of this survey, initiated by the Small Implants Group of the German Knee Society, was to gather opinions and put them into context of the current literature. METHODS: Based on the Delphi method and the AWMF rules and standards, 19 statements were developed, which were presented to the members of the DKG and BVOU in an anonymous online survey using "SurveyMonkey". Overall, 410 colleagues participated. RESULTS: The biggest detected controversies were the determination of indications with respect to the body mass index and the existence of a patellofemoral arthrosis. A general consent was determined that a contralateral tibiofemoral arthrosis grade III - IV and meniscal deficiency in the contralateral compartment are an absolute contraindication. There was a consent that age is not a limitation for the implantation of an UKA. If a personal minimum volume of 15 implantations/year should be implemented was seen controversial. CONCLUSION: The personal opinion, eventually built by personal experiences, appears to be in conflict with the knowledge of scientific literature in many instances. Intensive training and education appears necessary.

Local infiltration analgesia with additional intraarticular catheter provide better pain relief compared to single-shot local infiltration analgesia in TKA.

PURPOSE: Local infiltration analgesia (LIA) has been proven to be efficient in total knee arthroplasty (TKA). However, the effect of single-shot LIA is temporarily limited. The objective of this prospective trial was to investigate if the potential benefits resulting from LIA can be prolonged by a continuous intra-articular perfusion of LIA. The hypothesis of the present study was that the use of an additional continuous intra-articular perfusion delivering LIA would result in less pain and better function compared to single-shot LIA in the immediate post-operative period. METHODS: 50 consecutively selected patients undergoing TKA received either a single-shot LIA (S-LIA group, 25 knees) or single-shot LIA combined with a continuous post-operative intra-articular perfusion for three post-operative days (CP-LIA group, 25 knees). VAS (visual analogue scale) for pain, pain medication consumption and flexion ability were recorded postoperatively for 6 days. All patients had the same implant, surgeon and intra- as well as post-operative setting. RESULTS: The VAS score was significantly better for CP-LIA 6 h after surgery and on post-operative day 1, 2 and 6. There was no significant difference with regard to additional opioid consumption or flexion ability of the knee. However, there was a trend of the CP-LIA group requiring less additional opioids over the complete post-operative period compared to the S-LIA group. There were no complications or revisions. CONCLUSION: LIA combined with an additional intra-articular catheter provides better short-term pain control compared to single-shot LIA. However, no significant differences in terms of knee flexion were observed. This limited benefit should be balanced against the additional costs and the possible higher risk of infection. LEVEL OF EVIDENCE: Level II.

Additional periarticular catheter shows no superiority over single-shot local infiltration analgesia alone in unicondylar knee replacement.

PURPOSE: Local infiltration analgesia (LIA) has attracted growing interest in recent years. To prolong the positive effects of LIA, a continuous intraarticular perfusion has been introduced in total knee arthroplasty with good clinical results. The purpose of the present study was to evaluate if similar results can be obtained with the use of a continuous periarticular perfusion in unicondylar knee arthroplasty (UKA). METHODS: 50 consecutively selected patients undergoing UKA received either a single-shot LIA (control group; n = 25) or single-shot LIA combined with a continuous postoperative periarticular perfusion for 2 postoperative days (intervention group, n = 25). VAS (visual analogue scale) for pain, pain medication consumption and range of flexion were recorded postoperatively for 6 days. The catheter was removed after 2 days. RESULTS: Only minor advantages of using a continuous periarticular catheter could be shown. Patients in the intervention group showed significant lower VAS scores on day 1 and required significant less pain medication on day 6. Further, there was a significant difference in the range of flexion on day 3, on which patients of the intervention group were able to bend the knee joint on average by 12° more than patients of the control group. On the other days, any significant differences between the two groups were not observed. CONCLUSION: In summary, the present study could not identify any superiority of a periarticular catheter over single-shot LIA in UKA. Because of additional costs and the potential risk of infection, the conclusion of this study is to not recommend adding a periarticular catheter to the single-shot LIA in UKA. LEVEL OF EVIDENCE: II.

Variations in medial and lateral slope and medial proximal tibial angle.

PURPOSE: The primary objective of this study was to quantify the variations of the medial posterior tibial slope (MPTS) and the lateral posterior tibial slope (LPTS), as well as of the medial proximal tibial angle (MPTA), and to determine the fraction of patients for which standard techniques including different alignment techniques would result in alteration of the patient's individual posterior tibial slope (PTS) and MPTA. Furthermore, it was of interest if a positive correlation between PTS and MPTA or between medial and lateral slope exists. METHODS: A retrospective study was performed on CT-scans of 234 consecutively selected European patients undergoing individual total knee replacement. All measurements were done on three-dimensional CAD models, which were generated on the basis of individual CT-scans, including the hip, knee, and ankle center. Measurements included the medial and lateral PTS and the MPTA. PTS was measured as the angle between the patient's articular surface and a plane perpendicular to the mechanical axis of the tibia in the sagittal plane. MPTA was defined as the angle between the tibial mechanical axis and the proximal articular surface of the tibia in the coronal plane. RESULTS: Analysis revealed a wide variation of the MPTS, LPTS, and MPTA among the patients. MPTS and LPTS varied significantly both interindividually and intraindividually. The range of PTS was up to 20° for MPTS (from - 4.3° to 16.8°) and for LPTS (from - 2.9 to 17.2°). The mean intraindividual difference between MPTS and LPTS in the same knee was 2.6° (SD 2.0) with a maximum of 9.5°. MPTA ranged from 79.8 to 92.1° with a mean of 86.6° (SD ± 2.4). Statistical analysis revealed a weak positive correlation between MPTA and MPTS. CONCLUSION: The study demonstrates a huge interindividual variability in PTS and MPTA as well as significant intraindividual differences in MPTS and LPTS. Therefore, the question arises, whether the use of standard techniques, including fixed PTSs and MPTAs, is sufficient to address every single patient's individual anatomy. LEVEL OF EVIDENCE: III.

Superior clinical results and higher satisfaction after customized compared with conventional TKA.

Investigation of functional outcome and patient`s satisfaction after implantation of a customized versus conventional TKA. In 31 consecutively enrolled patients with primary gonarthrosis, 33 customized TKA (custTKA) and in 31 patients, a conventional TKA (convTKA) was implanted. Perioperative and postoperative management were identical. Radio- graphic evaluation, ROM, KSS (Knee society score) and WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) were performed and patients satisfaction was evaluated after 3 and 12 months. Groups were comparable for age, sex, body mass index and extension/flexion. After 92 days average flexion in the convTKA group was significantly higher (119 vs. 113 degrees; unpaired t-test). At 375 days, mean flexion in both groups was 120 degrees. There was a significant higher number of outliers of neutral mechanical axis for convTKA patients (11 vs. 3; Chi-squared test). After 92 days there was no difference for KSS (convTKA: 160, custTKA: 167) but significant better results for WOMAC (19 vs. 40) in the custTKA group (unpaired t-test, p= 0.02). In addition, significantly better KSS (181 vs. 156) and WOMAC (99 vs. 42) were found for the custTKA group at 375 days (unpaired t-test, p= 0.002 and 0.001). Patients with the custTKA implant reported significant higher fulfillment of their expectations regarding function and knee strength. In the present study, the patients with a custTKA implant showed significantly superior short-term clinical results and fulfillment of their expectations regarding knee function.

[Custom made total knee arthroplasty : Review of current literature]. / Der individuelle bikondyläre, kreuzbanderhaltende Oberflächenersatz am Kniegelenk : Aktuelle Literaturübersicht.

Custom-designed total knee replacement has become a standard procedure in some orthopaedic centres worldwide. Due to the lack of literature, the discussion about the hypothetical advantages has remained controversial. It was the aim of this study to focus on the current literature on custom-made total knee arthroplasty. We can demonstrate that custom-made total knee arthroplasty is a reproducible strategy with good clinical results in terms of leg-axis reconstruction, natural kinematics, patient-related outcomes and cost effectiveness. This has led to the fact that the Orthopaedic Data Evaluation Panel (ODEP) of the National Health Service in Great Britain rated the Conformis custom-designed knee replacement in 2017 with a 3D rating.