[The Berlin diagnostic algorithm for painful knee TKA]

The Impact of Dorsal Root Ganglion Stimulation on Pain Levels and Functionality in Patients With Chronic Postsurgical Knee Pain

BACKGROUND

Chronic postsurgical pain is a considerable source of disabling neuropathic pain. Rates of knee replacement surgeries are increasing, and many patients report chronic postsurgical pain in their wake. When conventional therapies prove ineffective, neuromodulation options such as dorsal root ganglion stimulation (DRGS) may be used. However, little is known about the effect of DRGS on improvements in quantitative functional outcome parameters.

MATERIALS AND METHODS

In a prospective observational study at two pain centers, patients with chronic postsurgical knee pain underwent implantation with a DRGS system after an interdisciplinary multimodal pain program. Ratings of pain, mood, quality of life, and function were captured at baseline and through 12 months of treatment. Quantitative measures (range of motion, walking distance, and pain medication usage) were also recorded.

RESULTS

Visual analog scale ratings of pain decreased from 8.6 to 3.0 (p < 0.0001; N = 11), and other pain measures agreed. Quality of life on the 36-Item Short Form Health Survey questionnaire improved from 69.3 to 87.6 (p < 0.0001), whereas the improvement in depression ratings was nonsignificant. International Knee Documentation Committee questionnaire ratings of function improved from 27.7 to 51.7 (p < 0.0001), which aligned with other functional measures. On average, knee range of motion improved by 24.5°, and walking distance dramatically increased from 125 meters to 1481. Cessation of opioids, antidepressants, and/or anticonvulsants was achieved by 73% of participants.

CONCLUSIONS

Both subjective-based questionnaire and quantitative examination-based variables were in broad agreement on the value of DRGS in improving functionality and chronic postsurgical pain in the knee. Although this finding is limited by the small sample size, this intervention may have utility in the many cases in which pain becomes problematic after orthopedic knee surgery.

No difference in patient reported outcome and inflammatory response after coated and uncoated total knee arthroplasty - a randomized controlled study

BACKGROUND

Allergies against implant materials are still not fully understood. Despite controversies about its relevance, some patients need treatment with hypoallergenic implants. This study compared coated and standard total knee arthroplasty (TKA) regarding inflammatory response and patient-reported outcome measures (PROMs).

METHODS

76 patients without self-reported allergies against implant materials were included in a RCT and received a coated or standard TKA of the same cemented posterior-stabilized knee system. 73 patients completed the 3-year follow-up. Two patients died and there was one revision surgery. Serum levels of cytokines with a possible role in implant allergy were measured in patient`s serum (IL-1beta, IL-5, IL-6, IL-8, IL-10, IFN γ, TNF α) prior to, one and three years after surgery. Furthermore, PROMs including knee function (Oxford Knee Score, Knee Society Score) and health-related quality of life (QoL, EuroQuol questionnaire) were assessed. Additionally, 8 patients with patch-test proven skin allergy against implant materials who received the coated implant were assessed similarly and compared to a matched-pair group receiving the same implant.

RESULTS

There were no differences in function and QoL between the assessed groups at any follow-up. The majority of patients demonstrated no elevation of the measured blood cytokines. Cytokine patterns showed no differences between study groups at any follow-up. The allergy patients demonstrated slower functional improvement and minor differences in cytokine pattern. Yet these results were not significant. There were no differences in the matched-pair analysis.

CONCLUSION

We observed no relevant increase in serum cytokine levels in any group. The inflammatory response measured seems limited, even in allergy patients. Furthermore, there were no differences between coated and standard TKA in non-allergy patients in the 3-year Follow-Up period.

TRIAL REGISTRATION

The study protocol was registered in the US National Institutes of Health's database ( http://www.

CLINICALTRIALS

gov ) registry under NCT03424174 on 03/17/2016.

SPECT/CT of Total Ankle Arthroplasty

Use of SPECT/CT (Single Photon Emission Computed Tomography/Computed Tomography) is increasing providing additional information in patients with inconclusive clinical examination and unremarkable imaging findings presenting with chronic pain after total ankle arthroplasty. To differentiate the cause of pain after total ankle arthroplasty can be challenging. SPECT/CT combines structural and metabolic imaging as a hybrid tool leading to higher specificity and overall diagnostic accuracy presumably in cases of gutter impingement, prosthetic loosening, and osteoarthritis of adjacent joints. Moreover, SPECT/CT can complement diagnostic work up in periprosthetic joint infections. Basal tracer enhancement has to be considered for the interpretation of imaging findings.

A Novel Multilayer-Coating for Total Knee Arthroplasty Implants is Safe - 10-Year Results From a Randomized-Controlled Trial

BACKGROUND

This randomized-controlled trial was initiated to compare a new multilayer hypoallergenic coating system with the standard implant in total knee arthroplasty (TKA) in terms of serum metal ion levels, patient-reported outcomes (PROs), and implant survival.

METHODS

A total of 120 patients were randomized to receive a coated or standard TKA of the same knee system. Serum metal ion levels (ie, cobalt, chromium, molybdenum, and nickel) as well as knee function (Oxford Knee Score, OKS), quality of life (SF-36), and physical activity (UCLA activity scale) were assessed before surgery and until the 10 year follow-up. A total of 24 patients died and there was one revision in each group. This resulted in 85 patients who completed follow-up.

RESULTS

Both groups demonstrated equally good improvement in PROs after surgery and constant score values thereafter. The majority of patients had metal ion serum levels below detection limit. Only cobalt levels demonstrated a slight increase in the standard group at 5- and 10-year follow-up. However, all patients displayed values below 3 μg/L. The cumulative 10-year survival was 98% in both groups.

CONCLUSION

There were no problems with the new coating system. No relevant increase in metal ion serum levels were measured. A slight increase in cobalt serum levels in the standard TKA was noted, thus not reaching critical values. The new coating system demonstrated equally good PROs as the standard TKA. Excellent implant survival was observed in both groups.

LEVEL OF EVIDENCE

I.

Failure Analysis in Multiple TKA Revisions-Periprosthetic Infections Remain Surgeons' Nemesis

BACKGROUND

The aim of this study was to categorize reasons for failure and to analyze the survivorship of multiple total knee arthroplasty (TKA) revisions.

METHODS

The study retrospectively evaluated all multiple TKA revisions performed between 2005 and 2015 at the authors' institutions. Sixty-three patients (35 female, 28 male, age 64 ± 10 years, follow-up 55 ± 36 months) underwent a total of 157 re-revision TKA surgeries (range 2-5). The revision indications were divided up into main diagnoses. Survivorship was evaluated by mixed model analysis.

RESULTS

The main overall reason for re-revision was periprosthetic joint infection (PJI) (48%), followed by instability (12%), polyethylene wear (11%), malpositioning (8%), and aseptic loosening (8%). Survivorship shortened with an increasing number of revision surgeries (p = 0.003). While PJI was in 38% of all cases, the reason for the first revision, incidence increased constantly with the number of revisions (48% at second revision, 55% at third revision, 86% at fourth revision, and 100% at fifth revision, p = 0.022). If periprosthetic infection caused the first revision, patients showed an average of two more septic revisions at follow-up than patients with an aseptic first revision indication (p < 0.001). In 36% of cases, the reason for follow-up surgery in case of periprosthetic infection was again PJI.

CONCLUSION

The probability of survival of the implanted knee arthroplasty is significantly reduced with each subsequent revision. Periprosthetic infection is the main cause of multiple revisions.

Diagnosis of Chronic Infection at Total Hip Arthroplasty Revision Is a Question of Definition

Purpose

Contradicting definitions of periprosthetic joint infection (PJI) are in use. Joint aspiration is performed before total hip arthroplasty (THA) revision. This study investigated the influence of PJI definition on PJI prevalence at THA revision. Test quality of prerevision aspiration was evaluated for the different PJI definitions.

Methods

256 THA revisions were retrospectively classified to be infected or not infected. Classification was performed according to the 4 different definitions proposed by the Musculoskeletal Infection Society (MSIS), the Infectious Diseases Society of America (IDSA), the International Consensus Meeting (ICM), and the European Bone and Joint Infection Society (EBJIS). Only chronic PJIs were included.

Results

PJI prevalence at revision significantly correlated with the applied PJI definition (p = 0.01, Cramer's V = 0.093). PJI prevalence was 20.7% for the MSIS, 25.4% for the ICM, 28.1% for the IDSA, and 32.0% for the EBJIS definition. For synovial fluid white blood cell count, the best ROC-AUC for predicting PJI was 0.953 in combination with the MSIS definition.

Conclusion

PJI definition significantly influences the rate of diagnosed PJIs at THA revision. Synovial fluid white blood cell count is a reliable means to rule out PJI. In cases with a borderline high synovial white blood cell count before THA revision as the only sign of chronic PJI, an extended diagnostic work-up should be considered.

[Diagnosis of loosening after knee arthroplasty]

BACKGROUND

Aseptic loosening is one of the most common reasons for revision in knee arthroplasty. Its pathogenesis is multifactorial, and early diagnosis is necessary to initiate appropriate therapy and to avoid serious complications, such as substantial bone loss or even periprosthetic fractures.

OBJECTIVES

This paper describes the current standard in the diagnosis of aseptic loosening in total knee arthroplasty. Sensitivity and specificity of the individual diagnostic procedures are presented, and other causes for differential diagnoses of painful total knee arthroplasty (TKA) are discussed.

RESULTS

In the case of suspected loosening in TKA, infection diagnostics should be performed to rule out periprosthetic infection, as this is crucial in terms of surgical strategy. The gold standard in diagnosing aseptic loosening is conventional radiography. Radiolucent lines at the cement-bone or metal-cement interface of more than 2 mm or increasing in translucency, migration of components, and cement fractures are obvious signs of loosening. Artifact-reduced computed tomography can bring additional information regarding periprosthetic osteolysis. A single bone scan is not reliable in diagnosing aseptic loosening, especially in the first 2 years after surgery. Single photon emission computed tomography (SPECT-CT) could be a useful extension in loosening diagnosis in the future.

CONCLUSIONS

The diagnosis of aseptic loosening poses a great challenge to the treating physician and requires a structured diagnostic algorithm. After exclusion of infection, conventional radiography is the basic examination, which should be supplemented by computed tomography and nuclear medicine examinations according to the clinical symptoms and the time course.

Biomechanical Particularities in the Therapy of the Rheumatic Knee

In rheumatoid arthritis, the joints of the lower extremities are almost always affected. This is most conspicuous in the knee joint. In rheumatics, inflammatory osteoarthritis manifests itself comparably earlier than in patients with osteoarthritis. The focus of attention was primarily on the synovia with its destruction process and secondary changes. Now, driven by experimental research, dendritic cells and fibroblasts and molecular features are moving into the clinician’s field of vision. Even in joints that appear to be in remission with no swelling or pain, the activity of these cells leads to changes in the capsule-ligaments. The complex deformities and instabilities caused by this, in conjunction with atrophy of the inter-articular musculature, have an impact on the activities of daily life (ADL). If these biomechanical aspects of the knee joint are not taken into account early on in therapy, the frequency of primary and secondary surgical treatment increases. The timely recognition of biomechanical pathologies and consistent treatment can contribute to improving the patient situation in addition to adequate medication therapy.

[Revision Total Knee Arthroplasty]

In addition to periprosthetic infections (PJI), the reconstruction of bony defects is the major challenge of revision total knee arthroplasty (TKA). Infection should be ruled out in all cases prior to operation. Revision TKA requires intensive planning with regard to the needed augmentation possibilities and the stems to be used. The sole biological reconstruction of major defects (AORI II and III) shows high failure rates. Large defects must be augmented by metal (wedges/sleeves/cones). The concept of zonal anchorage (3-zone model) with a stable anchorage in 2 out of 3 zones as close to the joint as possible is currently the standard. According to the model, metaphysis (zone 2) is an increasingly important factor for long-term stable anchoring. The use of cones or sleeves seems to significantly improve the results of revision TKA. The anchorage in zone 3 via stems is still mandatory. Cemented metaphysary anchoring and cement-free diaphysary anchoring stems are available, whereby no clear recommendation for a principle can be given.

The diagnostic potential of low-field MRI in problematic total knee arthroplasties - a feasibility study

Purpose

Low-field MRI, allowing imaging in supine and weight-bearing position, may be utilized as a non-invasive and affordable tool to differentiate between causes of dissatisfaction after TKA (‘problematic TKA’). However, it remains unclear whether low-field MRI results in sufficient image quality with limited metal artefacts. Therefore, this feasibility study explored the diagnostic value of low-field MRI concerning pathologies associated with problematic TKA’s’ by comparing low-field MRI findings with CT and surgical findings. Secondly, differences in patellofemoral parameters between supine and weight-bearing low-field MRI were evaluated.

Methods

Eight patients with a problematic TKA were scanned using low-field MRI in weight-bearing and supine conditions. Six of these patients underwent revision surgery. Scans were analysed by a radiologist for pathologies associated with a problematic TKA. Additional patellofemoral and alignment parameters were measured by an imaging expert. MRI observations were compared to those obtained with CT, the diagnosis based on the clinical work-up, and findings during revision surgery.

Results

MRI observations of rotational malalignment, component loosening and patellofemoral arthrosis were comparable with the clinical diagnosis (six out of eight) and were confirmed during surgery (four out of six). All MRI observations were in line with CT findings (seven out of seven). Clinical diagnosis and surgical findings of collateral excessive laxity could not be confirmed with MRI (two out of eight).

Conclusion

Low-field MRI shows comparable diagnostic value as CT and might be a future low cost and ionizing radiation free alternative. Differences between supine and weight-bearing MRI did not yield clinically relevant information.

The study was approved by the Medical Research Ethics Committees of Twente (Netherlands Trial Register: Trial NL7009 (NTR7207). Registered 5 March 2018, https://www.trialregister.nl/trial/7009).

[Predictors for persistent pain and dissatisfaction after total knee arthroplasty]

BACKGROUND

A substantial number of patients patients suffer from persistent pain or are unsatisfied after total knee arthroplasty (TKA).

OBJECTIVES

This work aims to present the frequency of postoperative persistent pain and/or dissatisfaction as well as known causes and predictors.

MATERIALS AND METHODS

The current literature is studied regarding the subject and is reviewed narratively.

RESULTS

Most postoperative problems did not arise from operation details, but from patient-related criteria, a lack of patient education and selection. The satisfaction correlates most strongly with the reduction of preoperative pain.

CONCLUSION

For a successful TKA, care should be taken that the following aspects are met preoperatively: clinically and radiologically advanced osteoarthritis, a patient age preferably older than 60 years, sufficient psychosocial resources to cope with postoperative stress, no opioid medication and realistic expectations after TKA. Postoperatively, patients with persistent pain or dissatisfaction should be checked for any prosthesis-related problems. If no prosthesis-related problems could be detected, the patients should be referred for interdisciplinary therapies.

Periprosthetic infection is the major indication for TKA revision - experiences from a university referral arthroplasty center

Background

We hypothesized, that periprosthetic joint infection (PJI) accounts for the major proportion of first (primary) and repeated (secondary) Total Knee Arthroplasty revisions at our university referral arthroplasty center.

Methods

One thousand one hundred forty-three revisions, performed between 2008 and 2016 were grouped into primary (55%) and secondary (45%) revisions. The rate of revision indications was calculated and indications were categorized by time after index operation. The odds ratios of the indications for primary versus secondary revision were calculated.

Results

In the primary revision group PJI accounted for 22.3%, instability for 20.0%, aseptic loosening for 14.9% and retropatellar arthrosis for 14.2%. PJI (25.6%) was the most common indication up to 1 year after implantation, retropatellar arthrosis (26.8%) 1–3 years and aseptic loosening (25.6%) more than 3 years after implantation.

In the secondary revision group PJI accounted for 39.7%, aseptic loosening for 16.2% and instability for 13.2%. PJI was the most common indication at any time of revision with 43.8% up to one, 35.4% 1–3 years and 39.4% more the 3 years after index operation.

The odds ratios in repeated revision were 2.32 times higher (p = 0.000) for PJI. For instability and retropatellar arthrosis the odds ratios were 0.60 times (p = 0.006) and 0.22 times (p = 0.000) lower.

Conclusions

PJI is the most common indication for secondary TKA revision and within one year after primary TKA. Aseptical failures such as instability, retropatellar arthrosis and aseptical loosening are the predominant reasons for revision more than one year after primary TKA.