[Successful medial unicompartmental knee arthroplasty-What are the most important surgical tricks?] / Erfolgsfaktoren für den medialen Teilgelenkersatz ­ Was sind die wichtigsten chirurgischen Tricks?

BACKGROUND: Unicompartmental knee arthroplasty (UKA) is an established surgical treatment option for end-stage anteromedial osteoarthritis with excellent functional outcomes and implant survival. Routine preoperative varus and valgus stress views are crucial for the selection of patients for unicompartmental or total knee arthroplasty. THERAPY: UKA is a soft-tissue based operation that aims to reconstruct the individual joint line and pre-arthritic alignment by restoring the physiological tension of the medial collateral and the cruciate ligaments. RESULTS: Current data for medial UKA show excellent results for both mobile and fixed bearing implant designs with the correct indication and surgical technique. Cementless fixation offers potential advantages over cemented implants. Registry data demonstrate that institutions and surgeons specializing in partial knee replacement (> 30 cases/year per surgeon, > 100/year per institution) with a high percentage of UKA relative to the total number of knee implants (> 20%) have significantly lower revision rates.

Meniscal Repair Outcome in 3829 Patients With a Minimum Follow-up From 2 Years Up to 5 Years: A Meta-analysis on the Overall Failure Rate and Factors Influencing Failure.

BACKGROUND: The importance of meniscal repair is widely accepted because of the association of loss of meniscal tissue with the development of early-onset knee arthritis. Many factors influencing the results of meniscal repair have been reported, but results remain controversial. PURPOSE: This meta-analysis determines the pooled meniscal repair failure rate of studies with a minimum follow-up of 2 years up to 5 years, with a mean follow-up of 43 months. Moreover, selected failure-influencing factors are analyzed. STUDY DESIGN: Systematic review and meta-analysis; Level of evidence, 4. METHODS: PubMed and Scopus were searched for studies published between January 2000 and November 2021 reporting on meniscal repair outcome with a minimum follow-up of 24 months. The overall pooled failure rate and pooled failure rates for possible predictors were calculated. Random-effect models were used to pool failure rates, and effect estimates in the form of odds ratios with 95% CIs were established. RESULTS: The initial literature search identified 6519 studies. A total of 51 studies met the inclusion criteria. In total, 3931 menisci were included with an overall failure rate of 14.8%. Subgroup analysis revealed a significantly lower failure rate for meniscal repair with concomitant anterior cruciate ligament (ACL) reconstruction compared with knees without any reported injury to the ACL (8.5% vs 14%; P = .043). The pooled failure rate for lateral meniscal repair was significantly lower than that for medial meniscal repair (6.1% vs 10.8%; P = .031). Pooled failure rates of all-inside and inside-out repair were not significantly different (11.9% vs 10.6%; P > .05). CONCLUSION: This meta-analysis on close to 4000 patients demonstrates an overall meniscal repair failure rate of 14.8% at a minimum follow-up from 2 years up to 5 years. Meniscal repair remains a procedure with a high failure rate, especially within the first 2 postoperative years. This review and meta-analysis also identified clinically relevant factors associated with favorable outcomes such as concomitant ACL reconstruction or repair of the lateral meniscus. All-inside meniscal repair with the latest-generation devices yields failure rates of <10%. The failure mechanism and the time of failure is poorly documented; further studies are needed for a better understanding of the retear mechanism.

Online Videos Regarding Relevant Postoperative Patient Information and Postoperative Rehabilitation After Arthroscopic Rotator Cuff Repair Provide Poor Information Quality, Accuracy, and Reliability.

PURPOSE: To evaluate the information quality, accuracy, and reliability of YouTube videos regarding relevant postoperative patient information and postoperative rehabilitation after arthroscopic rotator cuff repair. METHODS: By use of The Onion Router (TOR) software and predefined search terms, 102 videos were assessed. Four scoring systems were used to evaluate included videos: (1) Journal of the American Medical Association (JAMA) benchmark criteria score; (2) Global Quality Score (GQS); (3) DISCERN score; and (4) a newly developed score, the Rotator Cuff Score (RCS). The RCS (0-30 points) was built based on the latest published evidence and guidelines from the American Academy of Orthopaedic Surgeons. Videos that scored up to 9 points were regarded as poor-quality videos. RESULTS: Most of the included videos provided poor information quality, accuracy, and reliability. Videos that were uploaded by medically trained professionals showed significantly better results for all scores compared with commercial or personal-testimony videos (JAMA benchmark criteria score, P < .001; GQS, P < .001; DISCERN score, P = .001; and RCS, P = .001). Multivariate linear regression showed that the involvement of medically trained professionals was a significant predictor of better results for all scores (JAMA benchmark criteria score, ß = 1.496 [P < .001]; GQS, ß = 1.105 [P < .001]; DISCERN score, ß = 11.234 [P < .001]; and RCS, ß = 5.017 [P < .001]). Surprisingly, the like ratio was significantly higher for videos that were uploaded by non-medically trained individuals (P = .041). CONCLUSIONS: The average information quality, accuracy, and reliability of YouTube videos regarding relevant postoperative patient information and postoperative rehabilitation after arthroscopic rotator cuff repair are poor. Videos from medically trained professionals provide significantly higher information quality; however, even these videos lack important information for a better understanding of arthroscopic rotator cuff repair. CLINICAL RELEVANCE: Because of the lack of a peer-review process, available videos on YouTube regarding relevant postoperative patient information and postoperative rehabilitation after arthroscopic rotator cuff repair are of low quality, accuracy, and reliability. However, patients increasingly visit YouTube to gather medical knowledge. Physicians should enlighten patients about these findings and should be able to provide alternative sources of high-quality information.

Do cobalt and chromium blood metal ion levels normalize after revision of failed metal-on-metal total hip replacements?

INTRODUCTION: Increased cobalt (Co) and chromium (Cr) serum levels are one reason for revision surgery in metal on metal (MoM) total hip arthroplasty (THA) patients. Dual mobility liners are a simple revision option; however, they preserve the metal shell and stem and it is therefore not clear if metal ion levels will fully normalize after revision surgery. MATERIAL AND METHODS: Between April 2013 and December 2017 25 hips (24 patients) underwent revision from a MoM THA to an off-label dual mobility liner. Five patients were lost to follow-up and one patient refused leaving 18 patients (11 men, 7 female, average age 63.9 years) for pre- and postoperative metal ion level blood tests at a minimum follow-up of 2 years. RESULTS: Fourteen patients were revised for osteolysis, two for elevated metal ion levels and two for fluid or cysts around the femoral or acetabular component. The average preoperative Co and Cr levels were 8.3 µg/l and 5.0 µg/l, respectively. At a minimum follow-up of 2 years (30-95 months), metal ions dropped to 0.8 µg/l. Harris Hip Score (HHS), Hip Osteoarthritis Outcome Score (HOOS), Visual Analog Scale (VAS) and the UCLA activity score improved non-significantly from pre- to postoperative. There was one postoperative complication in the study cohort. One patient with persisting pain required revision surgery to a standard acetabular component during the follow-up period. CONCLUSION: The off-label use of a dual-mobility liner in the current study resulted in normalization of the metal ion levels suggesting that preserving the cobalt-chromium acetabular component has little impact on ion levels. In addition, dual mobility liners have a low complication and revision rate.

Sport after Knee Replacement Surgery - a Review of Sport Habits and Key Surgical Aspects. / Sport mit Knieprothese ­ Wieviel Sport ist möglich und was gilt es zu beachten ?

As an increasing number of younger patients are undergoing total knee replacement (TKR) surgery, many wish to participate in sport, but still expect that the implant will survive for a extended period. Most of the current literature shows that patients predominantly participate in low impact activities, both before and after surgery. A few studies show that with appropriate previous experience, high-impact sports are possible and might not result in increased implant failure rates. These include a decrease in point loads on the polyethylene by using more conform bearing surfaces, avoidance of varus component alignment to minimise stresses at the implant bone interface and avoiding patella resurfacing to facilitate activities in deep knee flexion.A TKR is no longer an absolute contraindication for higher impact activities such as golf, tennis and ski. What is more important than implant specific factors seem to be patient specific factors, including preoperative activity level, and preoperative sport skills.The current review paper reports on the current sport habits of TKR patients, analyses biomechanical loads on the knee during different sport activities and reports on implant selection and technical considerations for the active patient undergoing TKR.

Nineteen percent of meniscus repairs are being revised and failures frequently occur after the second postoperative year: a systematic review and meta-analysis with a minimum follow-up of 5 years.

PURPOSE: Meniscus repair has gained increasing interest over the last two decades as loss of meniscus tissue predisposes to early onset knee arthritis. Although there are many reports of meniscus repair outcome in short-term studies, data on the long-term outcome of meniscus repair are still scarce. The purpose of this meta-analysis was to evaluate the overall failure rate of meniscus repair with a minimum follow-up of 5 years. Additionally, possible factors influencing meniscus repair outcome were assessed. METHODS: PubMed and Scopus were searched for studies of the last 20 years reporting on meniscus repair outcome with a minimum follow-up of 5 years. The study was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The search terms used for this study were ([meniscus OR meniscal] AND repair). Titles and abstracts were evaluated by two authors independently. Using meta package of R (version 3.6.2), random-effect models were performed to pool failure rates. Subgroup analyses were performed and effect estimates in form of an odds ratio with 95% CIs were established. RESULTS: In total, 12 studies with 864 patients were included. Degenerative tears were excluded in two studies and one study only included traumatic meniscus tears. Other studies did not state whether the cause of meniscus tear was degenerative or traumatic. Studies reporting meniscus repair outcome on root repairs, revision anterior cruciate ligament reconstruction, discoid menisci or ramp lesions were excluded. Revision surgery was used as failure definition in all included studies. The overall failure rate of meniscal repair at a mean follow-up of 86 months was 19.1%. There was no significant difference in meniscus repair outcome when performed in combination with anterior cruciate ligament reconstruction compared to isolated meniscus repair (18.7% vs. 28%; n.s.) or when performed on the lateral meniscus compared to the medial meniscus (19.5% vs. 24.4%; n.s.). There was no significant difference of meniscus repair outcome between vertical/longitudinal tears and bucket-handle tears (n.s.). Thirty-six percent of meniscus repair failures occur after the second postoperative year. The only significant finding was that inside-out repair results in a lower failure rate compared to all-inside repair (5.6% vs. 22.3%; p = 0.009) at 5 years. CONCLUSION: The overall meniscus repair failure rate remains nineteen percent in long-term studies. The cause of failure is poorly documented, and it remains unclear whether failure of the meniscus repair itself or additional adjacent tears lead to revision surgery. Despite the given technical advantages of all-inside repair devices, this meta-analysis cannot demonstrate superior outcomes compared to inside-out or outside-in repair at 5 years. LEVEL OF EVIDENCE: IV.

Specific knowledge and resilience affect short-term outcome in patients following primary total hip arthroplasty.

PURPOSE: The aim of the present study was to investigate the potential associations between specific knowledge, resilience and patient-reported outcome measures (PROMS) following primary total hip arthroplasty (THA). METHODS: In a cross-sectional prospective study, consecutive patients following primary THA were included at a rehabilitation center. A novel knowledge score and the validated Connor Davidson Resilience Scale (CD-RISC) were utilized to assess patients' specific knowledge and resilience, respectively. Additionally, patients completed a qualitative questionnaire regarding the information they had received. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), as well as the University of California and Los Angeles Score (UCLA) served as primary outcome measures. Stepwise multiple regression analysis was performed to identify potential predictors of outcome. RESULTS: A total of 103 patients at a mean age of 67.5 years (SD 10.5, 38-88) were included in the analysis at a median of 55.5 days (IQR 43-81) following primary THA. The mean knowledge and resilience scores were 3.8 (SD 1.6, 0-7) and 69.5 (SD 18.5, 0-100), respectively. Forty-seven percent of patients were afraid of harming their prosthesis and these patients had up to 59% worse WOMAC scores (p < 0.001). WOMAC scores on admission to rehabilitation were predicted by resilience and knowledge scores (R2 = 0.106, p = 0.036). UCLA scores at the time of admission were predicted by knowledge scores (R2 = 0.078, p = 0.007). CONCLUSION: The present study demonstrated that patients with a feeling of uncertainty had an inferior short-term functional outcome following primary THA. Moreover, it could be shown that higher specific knowledge and resilience are associated with a better functional outcome according to validated PROMS. While these findings need to be prospectively validated in future studies, specific patient knowledge and resilience may have a direct impact on the outcome of primary THA.

Higher patient knowledge and resilience improve the functional outcome of primary total knee arthroplasty.

BACKGROUND: A significant percentage of patients have an unfavorable outcome following primary total knee arthroplasty (TKA). This study aimed to evaluate whether specific knowledge about the implant and resilience can influence the functional outcome following TKA. METHODS: A consecutive series of 163 patients following primary TKA at a mean age of 70 years (SD 9.1 years) were included at a regional rehabilitation center between December 2015 and December 2016. Specific patient knowledge (scale 0-7), Connor Davidson Resilience Scale (CD-RISC), Western Ontario and McMaster Universities (WOMAC) score, University of California and Los Angeles (UCLA) score and constitutional parameters were assessed on admission. Pearson's correlation analysis and stepwise linear regression analysis were performed to investigate associations between knowledge, resilience and functional scores. RESULTS: The mean overall knowledge score was 3.5 out of 7 and the mean resilience score was 72.9 out of 100. Mean WOMAC and UCLA scores on admission were 23.8 and 5.5, respectively. Stepwise linear regression analysis identified knowledge and age as significant predictors of WOMAC scores (R2 = 14.3%, p = 0.003). Knowledge and resilience were identified as significant predictors of UCLA scores (R2 = 13.8%, p = 0.013). CONCLUSION: This study highlights the importance of patient-related factors as part of an integral patient care concept in TKA. Although the identified predictors still need to be refined, it could be demonstrated how better patient knowledge might ultimately lead to better functional outcome following TKA. Routinely assessing patients' resilience might be a useful tool to identify patients at risk for low activity levels. LEVEL OF EVIDENCE: III. Patient-reported outcome study.

What sports activity levels are achieved in long-term survivors with modular endoprosthetic humerus reconstruction following primary bone sarcoma resection?

BACKGROUND: The aim of the study was to assess (1) sports activity, (2) sports involving the upper extremities, (3) functional outcome and (4) sports-related complications of long-term survivors of primary malignant bone tumors of the proximal humerus. METHODS: A total of 18 patients with an endoprosthetic reconstruction for primary malignant bone sarcoma of the proximal humerus (8 male, 10 female, mean age 19.9 ± 8.4 years, range 7.8-37.4 years) with an average follow-up of 18.1 ± 7.4 years (range 6.7-29.8 years) were included. The type of sport, frequency, duration of each sport session and the University of California, Los Angeles (UCLA) activity score were assessed before surgery, at 1 year, 3 years and at the latest follow-up. Functional outcome was assessed by the Toronto extremity salvage score (TESS). RESULTS: The mean UCLA activity score decreased from 8.0 (±1.3, range 5-9) preoperative to 4.2 (±1.7, range 3-8) at 1­year follow-up (p < 0.05). After 3 years it increased to 5.1 (±1.75, range 3-8) and further to 7 (±1.8, range 4-9) at the last follow-up. The mean postoperative TESS was 80.8 (±6.4, range 75.7-91.4) at the latest follow-up. Patients who were initially more active without reconstruction including a synthetic mesh were more likely to develop soft tissue complications accompanied by proximal endoprothesis migration. CONCLUSION: Patients with a modular endoprosthetic reconstruction of the humerus following primary bone sarcoma resume participation in sports. Regarding the low incidence of periprosthetic infections, utilization of a synthetic mesh for reconstruction to prevent soft tissue complications in active patients should be considered.

The Functional Status of the ACL in Varus OA of the Knee: The Association With Varus Deformity and Coronal Tibiofemoral Subluxation.

BACKGROUND: The present article analyzes the association of the functional anterior cruciate ligament (ACL) status and the overall varus deformity and coronal tibiofemoral subluxation (CTFS) in varus OA of the knee. METHODS: One hundred consecutive knees with varus OA in 84 patients were prospectively included. Knees were divided into two groups, in accordance with the ACL status (functionally sufficient or insufficient). All included patients were potential candidates for unicompartmental knee arthroplasty with predominantly medial compartment OA. Knees with Kellgren/Lawrence ≥ grade 3 in the lateral compartment were excluded leaving 79 knees to be included in this study. Mechanical varus deformity and CTFS were evaluated on AP radiographs and valgus stress radiographs, and compared between the two groups. RESULTS: Knees with a functionally insufficient ACL had significantly more varus deformity on hip-to-ankle AP standing radiographs (P = .001) and on valgus stress radiographs (P = .017). CTFS on AP standing radiographs was significantly higher (P = .045) in knees with a functionally insufficient ACL. Seventy-three percent (8/11) of the ACL-insufficient knees had a varus deformity of ≥10° and 64% (7/11) of ACL-insufficient knees had CTFS ≥ 6mm. By contrast, only one patient (2%, 1/41) with an insufficient ACL had< 10° varus deformity and a CTFS of < 6mm. CONCLUSION: Functional ACL insufficiency in osteoarthritic varus knees is associated with greater varus deformity and more advanced CTFS. Seventy-three percent of ACL-insufficient knees had a varus deformity of ≥10° and 64% of ACL-insufficient knees a CTFS of ≥ 6mm. In the work-up for medial unicompartmental knee arthroplasty, functional ACL insufficiency is likely in knees with varus deformity of ≥10° and CTFS of ≥ 6mm.

The Effect of Hypotensive Anesthesia on Hemoglobin Levels during Total Knee Arthroplasty.

INTRODUCTION: Hypotensive epidural anesthesia (HEA) is used in total joint arthroplasty as a safe and effective blood-saving modality. In order to maintain the blood pressure and heart rate patients, receive 1000 to 1500 mL of lactated Ringer's solution during surgery. While HEA reduces the intraoperative blood loss, the effect of intravenous fluid loading on hemoglobin levels is not fully understood. The current study investigates the effect of HEA on perioperative hemoglobin levels. MATERIALS AND METHODS: The study included 35 patients operated on by a single surgeon undergoing primary total knee arthroplasty under HEA. Intraoperatively, at least 300 mL of intravenous fluid were given every 15 min over the first 60 min after HEA. Blood samples were drawn before entering the operating room, after HEA, as well as after inflation of the tourniquet, every 15 min thereafter, as well as in the recovery room and on postoperative days one and two. In addition, fluid in- and outtake was recorded. RESULTS: Patients received a mean 1275 mL during the 60 min of tourniquet time. The mean arterial pressure (MAP) 5 min after HEA dropped to 60 mmHg and reached a constant level of around 58 mmHg 15 min after HEA. The average hemoglobin level dropped from 13.9 g/dL prior to HEA, to 12.5 g/dL immediately after HEA (p < 0.001). Intraoperatively the hemoglobin level dropped further and reached 11.8 g/dL at 60 min in the absence of blood loss. CONCLUSIONS: Hypotensive epidural anesthesia and the resulting fluid substitution resulted in an average hemoglobin drop of 2.1 g/dL within the first 60 min. This needs to be taken into account when evaluating the need for blood transfusions after primary joint replacement surgery under HEA.

Online Videos Provide Poor Information Quality, Reliability, and Accuracy Regarding Rehabilitation and Return to Sport After Anterior Cruciate Ligament Reconstruction.

PURPOSE: To investigate the information quality available on YouTube regarding rehabilitation and return to sport (RTS) after anterior cruciate ligament reconstruction (ACLR). METHODS: By use of The Onion Router software and predefined search terms, 140 YouTube videos regarding rehabilitation and RTS after ACLR were systematically included. Three scoring systems were used to analyze the included videos: (1) Journal of the American Medical Association (JAMA) benchmark criteria; (2) Global Quality Score (GQS); and (3) self-developed scores for rehabilitation after ACLR and RTS after ACLR, following American Academy of Orthopaedic Surgeons guidelines and current evidence. RESULTS: The vast majority of the included videos offered poor information quality, reliability, and accuracy. Videos that were uploaded by medically trained professionals showed significantly higher information quality regarding rehabilitation (P = .006 for JAMA score, P < .001 for GQS, and P = .001 for rehabilitation score) and regarding RTS (P < .001 for JAMA score, P < .001 for GQS, and P < .001 for RTS score) compared with commercial videos or personal-testimony videos. Multivariate linear regression also revealed medically trained professionals as significant predictors of higher information quality regarding rehabilitation (ß = 0.496 [P < .001] for JAMA score, ß = 1.3 [P < .001] for GQS, and ß = 3.7 [P < .001] for rehabilitation score) and RTS (ß = 0.754 [P < .001] for JAMA score, ß = 1.3 [P < .001] for GQS, and ß = 5.3 [P < .001] for RTS score). CONCLUSIONS: The average information quality, reliability, and accuracy of YouTube videos regarding rehabilitation and RTS after ACLR are poor. The information quality of related YouTube videos from medically trained professionals is significantly higher compared with commercial videos or personal-testimony videos. CLINICAL RELEVANCE: Current YouTube videos regarding rehabilitation and RTS after ACLR do not meet the necessary quality standards. Physicians should also be able to provide alternative sources of high-quality information.

Sport and Physical Activity Following Primary Total Knee Arthroplasty: A Systematic Review and Meta-Analysis.

BACKGROUND: This systematic review and meta-analysis aims to analyze the sport habits of patients before and after primary total knee arthroplasty (TKA) by answering the following questions: (1) Is there a postoperative improvement of sport activity based on validated activity scores? (2) Does age influence the postoperative improvement of sport activity based on validated activity scores? (3) What are the preoperative and postoperative sport participation rates and the return to sport rates (RTS)? (4) What are the sport disciplines and sport patterns? METHODS: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, MEDLINE and Scopus were searched for studies reporting the physical activity level and sport habits of patients before and after primary TKA based on validated activity scores or an activity questionnaire. Random effect models were implemented to pool the mean differences (MDs) of activity score values and the difference between preoperative and postoperative sport participation rates. RESULTS: Twenty-five studies were included reporting on 6035 TKAs. Physical activity levels improved significantly according to the University of California, Los Angeles (UCLA) activity score (MD 1.55, 95% confidence interval [CI] 0.35-2.76, n = 1239, I2 = 99%, P < .01) and the Tegner score (MD 1.14, 95% CI -0.48 to 2.76, n = 483, I2 = 93%, P < .01). Younger patients (≤55 years) had the highest improvement in the UCLA activity scores following primary TKA (MD 3.12, 95% CI -1.79 to 8.04, n = 67, I2 = 96%, P < .01). Sport participation decreased slightly but not significantly (incidence rate difference -8%, 95% CI -0.14 to -0.2, n = 2673 patients, I2 = 38%, P = .09). The median RTS was 71.2%. Patients predominantly engaged in low-impact sports, especially walking, cycling, and swimming. CONCLUSION: According to validated activity scores, the level of physical activity significantly increases following primary TKA. Young patients (≤55 years) had the highest gain in physical activity according to the UCLA activity score following primary TKA. Sport participation shows a slight but nonsignificant decrease; intermediate and high-impact sports were abandoned to a large degree while participation rates for low-impact sports predominantly increased. RTS varied, although approximately 70% resume sport activities. LEVEL OF EVIDENCE: IV (review including case series).

Serum cobalt concentrations remain at low levels at a minimum of 20 years following metal-on-metal total hip arthroplasty.

AIMS: Second-generation metal-on-metal (MoM) articulations in total hip arthroplasty (THA) were introduced in order to reduce wear-related complications. The current study reports on the serum cobalt levels and the clinical outcome at a minimum of 20 years following THA with a MoM (Metasul) or a ceramic-on-polyethylene (CoP) bearing. METHODS: The present study provides an update of a previously published prospective randomized controlled study, evaluating the serum cobalt levels of a consecutive cohort of 100 patients following THA with a MoM or a CoP articulation. A total of 31 patients were available for clinical and radiological follow-up examination. After exclusion of 11 patients because of other cobalt-containing implants, 20 patients (MoM (n = 11); CoP (n = 9)) with a mean age of 69 years (42 to 97) were analyzed. Serum cobalt levels were compared to serum cobalt levels five years out of surgery. RESULTS: The median cobalt concentration in the MoM group was 1.04 µg/l (interquartile range (IQR) 0.64 to 1.70) at a mean of 21 years (20 to 24) postoperatively and these values were similar (p = 0.799) to cobalt levels at five years. In the CoP control group, the median cobalt levels were below the detection limit (< 0.3 µg/l; median 0.15 µg/l, IQR 0.15 to 0.75) at 20 years. The mean Harris Hip Score was 91.4 points (61 to 100) in the MoM group and 92.8 points (63 to 100) in the CoP group. CONCLUSION: This study represents the longest follow-up series evaluating the serum cobalt levels after 28 mm head MoM bearing THA and shows that serum cobalt concentrations remain at low levels at a mean of 21 years (20 to 24) after implantation.Cite this article: Bone Joint Res. 2020;9(3):145-150.

Radiofrequency Chondroplasty May Not Have A Long-Lasting Effect in the Treatment of Concomitant Grade II Patellar Cartilage Defects in Humans.

The effect of radiofrequency chondroplasty on cartilage tissue is not well studied. This prospective pilot study investigates the effect of radiofrequency chondroplasty on International Cartilage Repair Society (ICRS) grade II patellar cartilage defects using high-resolution magnetic resonance imaging (MRI) with T2 mapping. Six consecutive patients were treated for ICRS grade II patellar cartilage defects using radiofrequency chondroplasty. Before surgery and at defined follow-ups (2 weeks, 4 and 12 months) a high-resolution morphological 3 Tesla MRI with quantitative T2 mapping was performed. At baseline MRI, global T2 values of cartilage defects were increased (46.8 ms ± 9.7) compared to healthy cartilage (35.2 ms ± 4.5) in the same knee which served as reference. Two weeks after treatment, global T2 values (39.2 ms ± 7.7) of the defect areas decreased. However, global T2 values of the defect areas increased beyond the preoperative levels at 4 months (47.4 ms ± 3.1) and 12 months (51.5 ms ± 5.9), respectively. Zonal T2 mapping revealed that the predominant changes in T2 values occurred at the superficial cartilage layer. T2 mapping appears to be an ideal method to monitor cartilage degeneration after chondroplasty. Based on the small sample size of this pilot study, radiofrequency chondroplasty may cause cartilage damage and may not have a long-lasting effect in the treatment of grade II patellar cartilage defects. In five out of six patients, postoperative cartilage damage was observed on quantitative MRI. This study was therefore terminated before completion. We recommend only addressing the pathology which indicated arthroscopy and leaving concomitant cartilage lesions untreated.

The tibial spine sign does not indicate cartilage damage in the central area of the distal lateral femoral condyle.

PURPOSE: A radiographic overlap of the lateral femoral condyle and the lateral tibial spine ('tibial spine sign') might indicate lateral compartment cartilage damage and might be considered a contraindication for unicompartmental knee arthroplasty (UKA). Therefore, the following research questions were asked: (1) does the presence of a 'tibial spine sign' on radiographs correlate with cartilage lesions on the medial aspect of the lateral femoral condyle on corresponding MRIs?; (2) do cartilage lesions on the medial aspect of the lateral femoral condyle indicate cartilage damage in the central area of the distal lateral femur?; and 3) is the 'tibial spine sign' impacted by the degree of varus deformity, the amount of coronal tibiofemoral subluxation or the functional status of the ACL? METHODS: One hundred consecutive knees with varus OA in 84 patients were prospectively included. The relationship of the lateral femoral condyle and the tibial spine was graded from 0 to 2 based on the degree of overlap on AP standing knee radiographs. On MRI, cartilage on the medial aspect of the lateral femoral condyle was assessed. Cartilage in the weight-bearing area of the distal lateral femur was analysed according to the OARSI system. RESULTS: The 'tibial spine sign' assessment correlated well with the degree of cartilage damage on the medial aspect of the lateral condyle (rs = 0.7, p < 0.001) but did not impact histological OARSI grades in the central weight bearing area of the lateral condyle (n.s.). Mechanical varus and tibiofemoral subluxation were not associated (n.s.) with a positive tibial spine sign. Knees with suggestive ACL insufficiency on MRI had more often a positive tibial spine sign; however, this difference was not statistically significant (n.s.). CONCLUSION: A positive tibial spine sign does not indicate histologic cartilage damage in the central area of the distal lateral femur and may not be considered a contraindication for medial UKA. LEVEL OF EVIDENCE: Level III, diagnostic study.

[ARMD reaction patterns in knee arthroplasty : A novel hypothetical mechanism: hingiosis]. / ARMD-Reaktionsmuster bei Kniegelenkendoprothesen : Ein neuer hypothetischer Mechanismus: Hingiose.

BACKGROUND: There are case descriptions of pronounced peri-implant inflammatory reactions and necrosis in non-infectious knee joint replacements with metal-polyethylene pairing. OBJECTIVES: Due to the histopathological similarities to the dysfunctional metal-on-metal (MoM) hip joint replacement, MoM-like reactions in knee joint arthroplasty ("ARMD-KEP") are proposed and a histopathological comparison is made. MATERIALS AND METHODS: This analysis evaluates five cases of "ARMD-KEP" using: (1) the SLIM consensus classification, (2) the particle algorithm, (3) the CD3 focus score and (4) the AVAL score. The comparison groups consist of 11 adverse cases of MoM hip and 20 cases of knee joint arthroplasty without adverse reaction. RESULTS: The ARMD-KEP cases were identified as SLIM type VI. Their median ALVAL score was 10. The CD3 focus score confirmed an adverse reaction. Particle corrosion was found in two of five cases. CONCLUSIONS: This data indicates that, in rare cases, an adverse MoM-like reaction may be present in knee replacements, with inflammatory and immunological expression similar to that of the adverse MoM reaction in the hip. The pathomechanisms can be discussed as follows: (1) secondary metal-metal contact, (2) dysfunctional loading of the coupling mechanism and (3) corrosion of the metal components. Much like trunnionosis in the hip, the term "hingiosis" is proposed for corrosion phenomena in dysfunctional conditions of coupled knee endoprosthetic systems.

Ramp lesions are frequently missed in ACL-deficient knees and should be repaired in case of instability.

PURPOSE: The aim of the current study was (1) to provide an overview of common definitions and classification systems of ramp lesions (RL) and (2) to systematically review the available literature with regard to the diagnosis and treatment of RLs in anterior cruciate ligament (ACL)-deficient knees. METHODS: Following the PRISMA guidelines, MEDLINE and Scopus were searched for articles (1) reporting on acute or chronic ACL injuries, (2) with concomitant medial meniscus injury, (3) located at the posterior meniscocapsular attachment site (and red-red zone). Ex vivo studies, reviews and technical notes were excluded. RESULTS: Twenty-seven studies were included based on the criteria mentioned above. RLs are common in ACL-deficient knees with a prevalence ranging from 9 to 24%. RLs should especially be suspected in younger patients, patients with an increased meniscal slope and in patients with prolonged time from injury to surgery. The sensitivity of MRI for the detection of RLs ranges from 48 to 86% at a specificity of 79-99%. For arthroscopy, RLs are easily missed through standard anterior portals (sensitivity 0-38%). RL repair leads to a significant improvement of subjective knee scores, regardless of the specific fixation technique. For stable RLs, the literature suggests equivalent postoperative stability for trephination and abrasion compared to surgical RL repair. CONCLUSION: Ramp lesions are frequently missed in ACL-deficient knees on standard arthroscopy with anterior portals only. If a RL is suspected, exploration via an additional posteromedial portal is indicated. In case of instability, RL repair should be performed. LEVEL OF EVIDENCE: IV.

Five Questions to Identify Patients With Osteoarthritis of the Knee.

BACKGROUND: To treat the increasing number of patients with osteoarthritis (OA) of the knee, high-volume institutions rely on central referral services as first contact point. Depending on the grading of arthritis, patients will be referred to a nonoperative or operative care provider. The present study reports on a simple 5-step questionnaire to identify patients with OA (Kellgren/Lawrence [KL] grade ≥2) of the knee to improve efficiency of referrals. METHODS: We included 998 patients who contacted the physician referral service at the author's institution complaining of knee pain and divided them into 2 groups. The study group included patients with an appointment and consisted of 646 patients (345 women [53.4%] and 301 men [46.6%]). X-rays of the knee were graded according to the KL classification system. The control group of patients who did not make an appointment consisted of 352 patients (187 women [53.1%] and 165 men [46.9%]). These patients were contacted to evaluate whether they had been diagnosed with OA of the knee since their initial call, to assure that the study group was not exposed to a selection bias. RESULTS: Logistic regression revealed 5 questions as significant predictors for OA of the knee (KL grade ≥2). When combining both groups, an 86.9% sensitivity, a 73.3% specificity, and an 84.3% overall accuracy were reached, when patients answered 3 or more questions positively. CONCLUSION: The present study revealed a simple 5-step questionnaire to identify patients with OA of the knee. Implementation of the questionnaire has the potential to improve the accuracy of referral processes and streamline organization before the first appointment.

The influence of femoral and tibial bony anatomy on valgus OA of the knee.

PURPOSE: Approximately 10% of all patients that require a total knee arthroplasty present with valgus osteoarthritis (OA) of the knee. Valgus OA goes along with posterolateral bone loss and lateral soft tissue tightness. The role of malalignment on the development of OA is not fully understood. The current study investigates whether the femoral offset (FO), femoral mechanical-anatomical (FMA) angle, anatomical lateral distal femur angle (aLDFA), mechanical lateral distal femur angle (mLDFA), medial proximal femur angle (MPFA), medial proximal tibia angle (MPTA) or lateral distal tibia angle (LDTA) differ in patients with valgus OA of the knee. METHODS: FO, FMA angle, aLDFA, mLDFA, MPFA, MPTA and LDTA were assessed and compared between 100 consecutive knees with minimal valgus OA (50 male, 50 female) and 100 consecutive knees with minimal varus OA (50 male, 50 female). RESULTS: FO was significantly higher in males with valgus OA (p = 0.002) and females with varus OA (p = 0.01). The observed values for the FMA angle were significantly higher in males with valgus OA (p = 0.002) and females with varus OA (p = 0.041). The aLDFA and mLDFA were significantly smaller in all patients with valgus OA (p < 0.001). No differences between the varus and valgus groups were detected regarding MPFA (males: p = 0.052; females: p = 0.719). Tibial measurements showed significantly higher values for the MPTA (p < 0.001) in both valgus groups and no difference for LDTA (men: p = 0.139; women: p = 0.196). CONCLUSION: Bony alterations in the femoral anatomy seem to be more important than in the tibial anatomy. While in male patients with valgus OA, the main anatomic variation is the hypoplasia of the lateral femoral condyle, in females both decreased femoral offset of the hip as well as hypoplasia of the lateral condyle are present. LEVEL OF EVIDENCE: III.