Comparable bone penetration between antibiotic-loaded and plain bone cement in total knee arthroplasty.

INTRODUCTION: One of the main concerns around the use of antibiotic-loaded bone cement (ALBC) is the potential reduction in the mechanical properties of the cement when antibiotics are admixed. The purpose of this study was to determine whether there is a difference between plain cement and ALBC in terms of radiological intrusion into the bone in total knee arthroplasties (TKAs). METHODS: Prospective randomized study of 80 consecutive patients who underwent TKA. Depending on the cement used, patients were divided into two groups by a computer-generated randomization programme: the cement without antibiotic (Group 1) or the ALBC (Group 2). Cement intrusion was measured in postoperative radiographs in eight different regions in the tibial component and six regions in the femoral component. RESULTS: The average cement intrusion was similar in both groups (p = nonsignificance [n.s.]). Group 1 (plain cement) had an average cement intrusion in the femur of 1.4 mm (±0.4) and 2.4 mm (±0.4) in the tibia. In Group 2 (ALBC), the average cement intrusion in the femur came to 1.6 (±0.5) and 2.4 mm (±0.5) in the tibia. In 80% of the patients, the cement intrusion in the tibia averaged a minimum of 2 mm, being similar in both groups (p = n.s.). CONCLUSION: There are no differences in bone intrusion when comparing plain cement to ALBC. Therefore, the use of ALBC in primary TKA may be indicated, achieving optimal bone penetration. LEVEL OF EVIDENCE: Level I.

The Use of Erythromycin and Colistin Cement in Total Knee Arthroplasty Does Not Reduce the Incidence of Infection: A Randomized Study in 2,893 Knees With a 9-year Average Follow-Up.

BACKGROUND: One of the most severe complications of primary total knee arthroplasty (TKA) is prosthetic joint infection. Currently, the use of antibiotic-loaded cement for the prevention of infection is still controversial. The aim of the present study was to evaluate if the use of antibiotic-loaded cement reduces the infection rate in primary TKA in long-term follow-up (more than 5 years average follow-up). METHODS: This study is the follow-up extension of a prospective randomized study, with 2,893 cemented TKA performed between 2005 and 2010 at our institution. There were 2 different cohorts depending on which bone cement was used: without antibiotics (control group) or those loaded with erythromycin and colistin (study group). All patients received the same systemic prophylactic antibiotics. The patients were followed for a minimum of twelve months. The diagnosis of prosthetic joint infection was done according to Zimmerli criteria. RESULTS: In 1,452 patients, the prosthetic components were fixed using bone cement without antibiotics, whereas in 1,441 patients, bone cement was loaded with erythromycin and colistin. Both groups were comparable in terms of all the possible risk factors studied. We found a total of 53 deep infections, with a mean rate of 1.8%. There were no differences between the groups as to whether bone cement with or without antibiotics had been used (P = .58). The average duration of follow-up was 8.7 years. In terms of prosthetic revision due to aseptic loosening, there were no differences between groups (P = .32), with 33 revision arthroplasties in the control group and 37 in the study group. Moreover, we analyzed the erythromycin resistance rate, with no differences between both groups (P = .6). CONCLUSIONS: The use of erythromycin and colistin-loaded bone cement in TKA did not lead to a decrease in the rate of infection in long-term follow-up, a finding that suggests that its use would not be indicated in the general population.

The distal tibiofibular syndesmosis is a reliable landmark for 3° varus tibial resection in total knee arthroplasty: a radiological evaluation on 1296 cases.

PURPOSE: The purpose of this study was to evaluate the reproducibility and the accuracy of distal tibiofibular syndesmosis (DTFS) as landmark to perform controlled varus tibial resections during total knee arthroplasty (TKA). The hypothesis was that DTFS can be used to perform an accurate 3° varus tibial cut. METHODS: A retrospective analysis on a consecutive series of standard weightbearing full-length anteroposterior views of the lower limbs radiographic images was conducted. For each radiograph, the hip-knee-ankle (HKA) angle, the angle between the tibial mechanical axis and the line connecting the centre of the tibial spines and the DTFS (tibiofibular angle, TFA) and the medial proximal tibial angle (MPTA) were calculated. Each measurement was carried out twice by three independent observers, and intra- and inter-observer measurement reliability were assessed using the intraclass correlation coefficient (ICC) analysis. RESULTS: A total of 1296 lower limbs were analysed from a series of 648 weightbearing full-length anteroposterior radiographs. The ICC were > 90% for all measurements. The mean TFA value was 2.94 ± 0.68 (range 2.38-3.51). No differences were detected comparing the mean TFA value on the right and left limb (p = 0.795) as well as comparing the values in male and female patients (p = 0.691). Linear regression analysis did not find statistically significant correlation between TFA and MPTA, or TFA and HKA angles, respectively. CONCLUSION: The distal tibiofibular syndesmosis is a reliable and easy reproducible radiographic landmark that can be used when planning a 3° varus tibial cut. Future studies are needed to confirm the validity of this method also in clinical settings. LEVEL OF EVIDENCE: IV, retrospective case series.

Systematic lateral retinacular release does not reduce anterior knee pain after total knee arthroplasty with patellar resurfacing.

PURPOSE: The aim of this study was to assess the effect of systematic lateral retinacular release (LRR) on anterior knee pain (AKP), as well as its impact on the functional and radiological outcomes after total knee arthroplasty (TKA) with patellar resurfacing. METHODS: A prospective randomized study was designed. It included patients scheduled for a TKA procedure with patellar resurfacing, who were recruited and randomized into either the LRR group or the non-release group. 198 patients were included in the final analysis. The pressure pain threshold (PPT) assessed by pressure algometry (PA), the visual analogue scale (VAS), Feller's patellar score, the Knee Society Score (KSS), patellar height, and patellar tilt were recorded both preoperatively and at the 1-year follow-up. The Mann-Whitney U test was performed to determine comparisons between both groups as well as to determine differences' intragroup. RESULTS: Relative to the clinical variables and scores, no difference was detected between the two groups at the 1-year follow-up (p = n.s.). However, there was a slight difference in patellar tilt (0.1º vs. 1.4º, p = 0.044), with higher tilt values in the non-release group. There was no difference in terms of improvement in the clinical and radiological scores and variables recorded between the two groups (p = n.s.). CONCLUSION: LRR in primary TKA with patellar resurfacing does not show an improvement in AKP and functional outcomes over patellar resurfacing without release. LEVEL OF EVIDENCE: I.

Increased posterior translation but similar clinical outcomes using ultracongruent instead of posterior stabilized total knee arthroplasties in a prospective randomized trial.

PURPOSE: The aim of this study was to compare the posterior tibial translation after ultracongruent (UC) and posterior-stabilized (PS) total knee arthroplasty (TKA) with two different UC with different heights in the anterior lip, and two different PS designs. This study also aimed to compare the range of motion (ROM) and outcomes scores after the use of these TKA models. It was hypothesised less posterior tibial translation after PS than after UC TKA, and less posterior tibial translation with a higher anterior lip in the UC insert than with a lower one. METHODS: It was designed as a prospective randomized study of a group of 120 patients operated with a cemented TKA. To clarify the main purpose of the study, four groups were analysed using different polyethylene designs: Triathlon PS insert in group one, Triathlon UC insert in group two, U2 PS insert in group three and U2 UC insert in group four. One year after surgery, a forced posterior drawer with a Telos Stress applying 15 kg of force posteriorly on the proximal tibia at 90° of knee flexion was analysed in the lateral radiograph. Limb alignment, tibial posterior slope and posterior condylar offset were also studied. RESULTS: 30 patients were included in each group. The average age was 73 years. There were 72.2% female and 27.8% male patients. There were no significant differences in any demographic or radiographic studied variables, preoperative range of motion (ROM) or preoperative Knee Society Scores (KSS) among the different groups. One year after surgery, the average postoperative ROM and the postoperative KSS Knee and KSS Function scores improved in respect of the preoperative values in all the groups. There were no significant differences in the postoperative outcome scores among the different groups (p = n.s.). Postoperative alignment of the limb, tibial posterior slope and posterior condylar offset were similar in the 4 study groups (p = n.s.). The postoperative posterior tibial translation was different between groups: the PS groups (groups 1 and 3) showed significant inferior values (p < 0.001) in respect of the UC groups (groups 2 and 4). There were no differences between both groups of PS models, but there was a significant increase in the posterior tibial translation of the Triathlon UC insert (11.2 mm SD 3.2) in respect of the U2 UC insert (6.1 mm SD 4.5) (p = 0.004). CONCLUSIONS: UC inserts restrict the posterior tibial translation after TKA less than PS inserts, but a design with a high anterior lip in the polyethylene UC insert can better control the posterior tibial translation than an insert with a small anterior lip. LEVEL OF EVIDENCE: Level I. Randomised controlled trial.

The technique of cement application has no influence on cement intrusion in total knee arthroplasty: randomized study comparing three different techniques.

PURPOSE: The aim of the study was to compare the distance of intrusion of the cement into the bone in different areas both in the femur and the tibia in vivo, measured in the radiograph after implanting a total knee arthroplasty (TKA) with three different cement techniques. METHODS: A prospective randomized study of 90 consecutive patients operated on at our institution with a cemented U2 Knee System TKA and medium viscosity Simplex P® bone cement. After pulse lavage, the cement was applied on the bone surfaces (group 1), on the implant surfaces (group 2) or both on the bone and the implant surfaces (group 3). The cement intrusion was measured in the postoperative radiographs in eight different regions in the tibial component and in six regions in the femoral component. The cement employed was calculated by weighting the cement after mixing and weighting the discarded cement. RESULTS: The average intrusion of the cement was similar in all three groups of cementing techniques in the femoral components (1.6 mm; p = 0.386), and in the tibial components (2.6 mm; p = 0.144). The intrusion of the cement in the tibia was greater in women than in men (p = 0.04). We used 21.1 (SD 5.8) g of cement in average. The amount of cement employed was greater when the cement was applied on both (implant and bone) surfaces (group 3: 24.03 g in average) than when it was applied only on the bone (group 1: 20.13 g; p = 0.01) or only on the implants (group 2: 19.20 g; p = 0.001). The amount of cement employed was greater in men than in women (p = 0.002) and it was also greater when a PS femoral component was used (p = 0.03). The amount of cement employed was directly correlated with the height of the patients (p = 0.01) and with the bigger size of the components (p < 0.001). CONCLUSION: All three cement application techniques have similar intrusion distance of the cement into the bone, and the intrusion depth of the cement into the trabecular tibial bone is greater than the minimum suggested for fixation.

Preoperative muscle thickness influences muscle activation after arthroscopic knee surgery.

PURPOSE: The aim of this study was to compare the correlation between preoperative quadriceps femoris muscle thickness and postoperative neuromuscular activation and quadriceps femoris strength in patients with and without patellofemoral pain after arthroscopic partial meniscectomy. METHODS: A series of 120 patients were prospectively analysed in a longitudinal cohort study of patients scheduled for arthroscopic partial meniscectomy. The patellofemoral pain group included patients who developed anterior knee pain after surgery while the control group included those who had not done so. Patients with preoperative patellofemoral pain, previous knee surgeries as well as those on whom additional surgical procedures had been performed were excluded. Of the 120 initially included in the study, 90 patients were analysed after the exclusions. RESULTS: There is a direct correlation between preoperative quadriceps femoris muscle thickness and the neuromuscular activity values and the strength of the muscle at 6 weeks after surgery. These results were seen exclusively in the group of patients who do not develop patellofemoral pain (0.543, p = 0.008). The group of patients who developed anterior knee pain in the postoperative period did not show this correlation (n.s.). CONCLUSION: In patients without patellofemoral pain after meniscectomy, the greater the preoperative thickness of the quadriceps femoris, the more postoperative neuromuscular activation and strength they had. This correlation did not occur in those patients who develop patellofemoral pain after meniscal surgery. LEVEL OF EVIDENCE: II.

Patients lose weight after a total knee arthroplasty: myth or reality?

BACKGROUND: Obesity is one of most discussed factors when assessing prosthetic knee surgery outcomes. Prior to the procedure, most patients perceive that their excessive weight is secondary to the low level of activity due to limiting knee pain. OBJECTIVES: The main objective of this study was to assess whether patients undergoing total knee arthroplasty (TKA) lose weight after the procedure. The secondary objective was to correlate weight loss with post-operative knee function. METHODS: A prospective observational study was designed including 247 patients who undergone TKA from January 2018 to January 2019. A significant change in weight was considered anything above or below 5% of the pre-operative weight. Three groups were established based on a change in weight: loss of more than 5%, those who did not pass above or below 5% of their initial weight and increase of more than 5%. Follow-up was carried out at 12 months after the intervention assessing patient's BMI (kg/m2), functional level (KSS), weight loss expectations, and range of motion. RESULTS: Among the total population, 17 (6.9%) lost weight, 168 (68%) did not have a change, and 62 (25.1%) increased weight at one year follow-up. The mean pre-operative BMI was 31.5 kg/m2, and mean postoperative BMI was 31.98 kg/m2. Furthermore, obese patients were more likely to present weight reduction than non-obese (p = 0.01). When comparing functional results between groups, no differences were observed in terms of KSS-K and KSS-F. CONCLUSION: Patients who undergo TKA do not lose weight one year after surgery. When correlating weight loss with post-operative outcomes, no differences were observed between groups.

Adherence to a reliable PJI diagnostic protocol minimizes unsuspected positive cultures rate.

BACKGROUND: The aim of the present study was to evaluate the incidence of unsuspected PJI when prosthetic revisions are thoroughly evaluated by PJI dedicated orthopedic surgeon before surgery. The hypothesis is that the incidence of unsuspected PJI is reduced by applying this protocol. METHODS: This is a historical cohort study carried out in one university hospital. The prosthetic revision assessment was carried out in January 2019. From that date on, all patients that were programmed for hip or knee revision (either by an orthopedic surgeon specialized or not in septic revisions) were scheduled for a preoperative visit with the same orthopedic surgeon specialized in septic revisions. The diagnostic algorithm applied was based on the Pro-Implant Foundation diagnostic criteria. Prior to the revision assessment, the indication for joint aspiration was done at the surgeons' discretion (non-specialized in septic revisions) and the preoperative identification of PJI was also done by a hip or knee surgeon (not specialized in septic surgery). RESULTS: Based on the PIF criteria, there were 15 infections among the revisions in group 1 and 18 PJI in group 2 (p > 0.05). The most interesting finding was that there were 7 patients with unsuspected positive cultures in group 1. That represents 11% of all revisions. No patient in group 2 was found with unsuspected positive cultures (p < 0.001). CONCLUSION: A thorough PJI diagnostic algorithm should be implemented before prosthetic revision to avoid unsuspected positive cultures.

Patellar denervation does not reduce post-operative anterior knee pain after primary total knee arthroplasty with patellar resurfacing.

PURPOSE: Anterior knee pain (AKP) is a frequent symptom after a total knee arthroplasty (TKA). Patellar denervation (PD) has been put forth as a technique to reduce this pain; however, its effects have not been assessed in combination with patellar resurfacing. The aim of this study is to evaluate the effect of PD on AKP and functional outcomes after TKA with patellar resurfacing. METHODS: A prospective study was designed that included patients scheduled for TKA with patellar resurfacing. The 202 recruited patients were randomized into either the PD group or the non-denervation group [mean age 72.7 years (SD 8.2); 119 (70.4%) women and 50 (29.6%) men; average body mass index 31.4 kg/m2 (SD 4.9)]. Pressure pain threshold (PPT) assessed by pressure algometry (PA), visual analogue scale(VAS), patellofemoral Feller score and the Knee Society Scores (KSS) were recorded preoperatively and at the 1-year follow-up. RESULTS: 169 patients were included in data analysis. At the 1-year follow-up, there were mild differences between denervation and non-denervation group in PPT value (494.4 kPa vs. 552.3 kPa, p = 0.047) and in VAS at stairs (2.9 vs. 1.5, p = 0.003) in favour of the non-denervation group. There was no difference in the improvement between groups in patellofemoral Feller score and KSS, but slightly higher improvement in non-denervation group in PPT (94.1 kPa vs. 160 kPa, p = 0.047), VAS walking (5.3 vs. 6.2, p = 0.041) and VAS at stairs (4.6 vs. 5.7, p = 0.022). CONCLUSION: Patellar denervation does not improve AKP and clinical outcomes in primary TKA with patellar resurfacing compared to patellar replacement without denervation. PD cannot be recommended when patellar replacement is performed in TKA. LEVEL OF EVIDENCE: II.

Translation and validation of the new knee society knee scoring system into Spanish: Spanish KSS translation.

PURPOSE: The aim of the study was to translate and validate the English version of the 'Knee Society Knee Scoring System' developed in 2011 (2011 KSS) into Spanish. This new KSS version considers patient satisfaction and expectations before and after knee arthroplasty. Moreover, the questionnaire allows a better characterization of a younger and more diverse population. METHODS: A cross-cultural adaptation process was carried out to obtain the Spanish version of the questionnaire. After that, patients undergoing primary knee arthroplasty answered the translated questionnaire before and 6 months after surgery. Psychometric properties including feasibility, validity, reliability, and sensitivity to change were then assessed, and the questionnaire was compared with prior KSS, as well as with SF-12 and WOMAC, all of them already validated to Spanish. RESULTS: In the cross-cultural adaptation process, alternative translations of some items in 'Patient Expectative' and 'Functional Activities' sections were suggested. One hundred and seventy-six patients answered the resulting 1.0 version. Feasibility: 'Charnley Functional Classification', 'Deduction for flexion contracture and extensor lag', the question 'Do you use these aids because of your knees?', and 'Advanced activities (total)' obtained a high number of missing items. Eighty-eight patients (50%) in the preoperative visit and 141 patients (86.5%) after surgery had at least one missing answer. Internal validity: although the analysis suggests the presence of more than one dimension, there was a dimension that explained a higher percentage of variance, which was more noticeable in the postoperative visit. Convergent validity: correlation coefficients with prior KSS, SF-12, and WOMAC confirm the questionnaire's validity. Reliability: Cronbach's alpha for the new KSS was 0.841 and 0.861 in visit 1 and 2, respectively, and higher than that for prior KSS. Sensitivity to change: statistically, significant differences were found between the mean scores between both visits. CONCLUSION: The proposed Spanish version of 2011 KSS is valid, reliable, and sensible to change in patients undergoing primary knee arthroplasty. Moreover, it has higher internal consistency (reliability) than the prior KSS. It should be emphasized its correct filling by both health professional and patients LEVEL OF EVIDENCE: II.

Limb length discrepancy after total knee arthroplasty may contribute to suboptimal functional results.

PURPOSE: Limb length discrepancy (LLD) has been related to inferior outcomes after total hip arthroplasty (THA), but few studies have dealt with the LLD in primary total knee arthroplasty (TKA). The aims of the study were to examine the incidence of LLD after TKA and how it can influence in the outcomes scores. METHODS: We analysed preoperative, postoperative and changes in LLD in 460 patients who underwent a unilateral primary TKA. The measurements were done on digital full leg radiographs preoperatively and 6 months after surgery. The hip-knee-ankle (HKA) angle was also measured on these radiographs. Patients were evaluated with the Knee Society Score (KSS) preoperatively and 12 months after surgery. RESULTS: The average LLD was 1.1 mm in the preoperative period and changed to -0.8 mm in the postoperative (the 1.9 mm lengthening of the operated limb was statistically significant (p < 0.001)). LLD increase was correlated with preoperative HKA angle and with HKA angle changes. Only 8.3% of the patients had significant postoperative LLD (≥ 10 mm), but they had a significant worse function outcome in the KSS one year after surgery than patients with negligible postoperative LLD (< 10 mm) (76.7 vs 82.3; p = 0.02). CONCLUSIONS: Unlike THA surgery, significant LLD is not frequent after TKA surgery, but the functional results of the surgery can be suboptimal when it is present.

Pressure algometry is a suitable tool to assess anterior knee pain in osteoarthritic patients.

PURPOSE: Anterior knee pain is a frequent symptom in the osteoarthritic knee. Its intensity has been classically evaluated by the visual analogic score (VAS). The main objective of the study was to assess whether pressure algometry (PA) can be used as a reliable tool to quantify anterior pain in the osteoarthritic knee. METHODS: A prospective study was designed, including 160 patients scheduled for unilateral total knee arthroplasty. Patellar pain and function were evaluated according to a specific patellofemoral pain questionnaire and the Knee Society Score. Patients were asked about their pain at rest, while walking and in the stairs with the VAS score. PA by an algometer was used in the anterior part of the patella to determine the pressure pain threshold (PPT): the minimal pressure when the patient feels a painful sensation. RESULTS: The mean values of PPT were 385.1 kPa in the knees going to be operated and 403.4 kPa in the contralateral knees (p < 0.05). The anterior knee pain in the patellar score averaged 6.9, and the total patellar score averaged 15.2. PPT values were correlated with the anterior pain in the patellar score (ρ = 0.31, p < 0.001) and also with the total patellar score (ρ = 0.33; p < 0.001). CONCLUSIONS: PA demonstrated to be suitable to measure anterior knee pain in the osteoarthritic knee. PA can specifically assess the anterior knee pain better than other methods as VAS score. PA could be used as the main measurement when comparing different treatments for the anterior knee pain caused by osteoarthritis.

Contamination occurs during ACL graft harvesting and manipulation, but it can be easily eradicated.

PURPOSE: Why anterior cruciate ligament (ACL) autograft soaking in a 5 mg/ml vancomycin solution decreases the rate of infection has not been well-explained. One hypothesis is that grafts can be contaminated during harvesting and vancomycin eradicates the bacteria. The purpose of the present study is to assess how the vancomycin solution acts against ACL graft contamination during graft harvesting and preparation. METHODS: The study was carried out in three university hospitals over a period of 6 months. After sample size calculation, 50 patients were included in the study. Three samples were taken from each ACL graft. Sample 1 was obtained immediately after graft harvesting. After graft manipulation and preparation, the remaining tissue was divided into two parts. The raw sample was denominated sample 2 and sample 3 consisted of the rest of the remaining tissue that had been soaked in the vancomycin solution. All the cultures were incubated at 37 °C with 5% CO2 in agar plates for 7 days (aerobically) or 14 days (anaerobically) and inspected daily for microbial growth. Any bacterial growth and the number of colony forming units were reported. RESULTS: In seven cases (14%), either sample 1 or sample 2 was positive. In five of the cases (10%), only the sample after graft preparation was positive (sample 2). In two cases (4%), sample 1 and sample 2 were positive for the same bacteria. Isolated microorganisms corresponded to coagulase-negative staphylococci (CNS) and Propionibacterium acnes. No bacterial growth was observed in sample 3 (p < 0.001). Thus, none of those seven positive cases (0%) were positive after vancomycin soaking (p < 0.001). CONCLUSION: In the series, ACL graft harvesting and manipulation leads to bacterial contamination in 14% of the cases. This contamination is fully eradicated after soaking in the vancomycin solution in this series. LEVEL OF EVIDENCE: Level II.

Depressed patients feel more pain in the short term after total knee arthroplasty.

PURPOSE: The hypothesis of this study was that depressive patients feel more pain in the immediate TKA postoperative period in comparison with non-depressed patients. METHODS: The diagnosis of depression was made with the Geriatric Depression Scale Short Form. The Visual Analogic Score (VAS) was registered each 8 h during the first 3 days. The mean and maximum VAS and the number of analgesic rescues required in this period were calculated in 803 consecutive TKAs. The Knee Society Score (KSS), the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC), and the Short Form-36 (SF-36) scores were obtained preoperatively and at the 1-year follow-up. RESULTS: Forty-eight (6%) of these patients were considered depressed. The results obtained in the depressed patients and non-depressed were, respectively, mean VAS (2.0 vs 1.0, p = 0.00), maximum VAS (5.3 vs 1.6, p = 0.00), and number of rescues needed (4.4 vs 1.8, p = 0.00). Although depressed patients scored worse in the functional and quality of life scores in the preoperative period, the improvement obtained (1-year outcomes minus preoperative outcomes) in the different scores was similar in both groups with the exception of the mental domain of the SF-36, which improved further in depressed patients (p = 0.00). CONCLUSION: Depressed patients feel more pain in the immediate postoperative period. However, the improvement obtained in functional and referred quality of life scores is similar to non-depressed patients. LEVEL OF EVIDENCE: II.

No differences in functional results and quality of life after single-radius or multiradius TKA.

PURPOSE: The main objective of this study was to compare the functional results and the impact on quality of life after a single-radius or a multiradius TKA implantation. The secondary objectives were to compare range of motion, satisfaction and the ability to perform daily life activities with both types of implant. It was hypothesized that the single-radius TKA would lead to better functional results and better quality of life than the multiradius TKA. METHODS: This is a prospective non-randomized study that included 250 cases of a single-radius TKA and 224 of a multiradius posterior-stabilized TKA implanted with the same surgical and rehabilitation protocol. RESULTS: In the 1- and 5-year follow-up, we found similar knee KSS scores (89.7 ± 12.1 in the multiradius group and 90.3 ± 11.7 in the single-radius group) and functional KSS scores (78.6 ± 21.4 in the multiradius group and 75.8 ± 20.9 in the single-radius group). The pain and the Physical SF-36 scores were also similar. Range of motion (112° ± 12° in the multiradius group and 112 ± 12° in the single-radius group), patients' satisfaction and the ability to perform daily life activities were also similar in both groups. CONCLUSION: The use of a single-radius or a multiradius posterior-stabilized knee prosthesis can improve the function of the knee and the patients' quality of life in a similar way at the short-term and midterm follow-up. Moreover, range of motion, patient satisfaction and the ability to perform daily life activities are similar with both types of prosthesis. As both types of prosthesis can improve the function and quality of life of the patients in a similar way, the sagittal radius of the femoral component should not be considered the main factor when choosing the model of TKA. LEVEL OF EVIDENCE: Therapeutic study: Prospective comparative study, Level II.

Patient-reported allergies cause inferior outcomes after total knee arthroplasty.

PURPOSE: The main objective of this study was to analyse the outcomes after total knee arthroplasty (TKA) of a group of patients with at least one self-reported allergy and a group of patients without reported allergies. We hypothesized there is a significant negative influence on clinical outcome scores after TKA in patients with self-reported allergies. METHODS: Four-hundred and seventy-five patients who had undergone TKA were analysed preoperatively and 1 year after surgery. The WOMAC, KSS and SF-36 scores were obtained. The patients' Yesavage depression questionnaire score was also recorded. The scores of the 330 (69.5 %) patients without self-reported allergies were compared to the scores of the 145 (30.5 %) patients with at least one self-reported allergy in the medical record. RESULTS: Preoperative scores were similar in both groups. The WOMAC post-operative scores (23.6 vs 20.4; p = 0.037) and the KSS-Knee score (91.1 vs 87.6; p = 0.027) were worse in the group of patients with self-reported allergies than in the group without allergies. The scores from the Yesavage depression questionnaire and in the SF-36 were similar in both groups. CONCLUSION: Patients with at least one self-reported allergy have worse post-operative outcomes in terms of the WOMAC and KSS-Knee scores after TKA than patients without allergies. These poor outcomes do not seem to be related to depression. Therefore, more research is needed to explain them. Reported allergies could be considered a prognostic factor and used when counselling TKA patients. LEVEL OF EVIDENCE: I.

Local infiltration analgesia adds no clinical benefit in pain control to peripheral nerve blocks after total knee arthroplasty.

PURPOSE: To evaluate the effect of the local infiltration of analgesics for pain after total knee arthroplasty in patients treated with femoral and sciatic peripheral nerve blocks. The secondary objective was to detect differences in analgesic consumption as well as blood loss after local infiltration of analgesics. METHODS: Prospective randomized double-blinded study in patients who underwent a TKA for knee osteoarthritis under spinal anesthesia and treated with femoral and sciatic nerve blocks. This study compared 50 patients treated with local infiltration with ropivacaine, epinephrine, ketorolac and clonidine and 50 patients treated with a placebo with the same technique. The visual analogic score was registered postoperatively at 2, 6, 12, 24, 36, 48 and 72 h after surgery. Analgesic consumption was also registered. Both groups of patients were treated with the same surgical and rehabilitation protocols. RESULTS: A significant difference of one point was found in the visual analogic pain scores 12 h after surgery (0.6 ± 1.5 vs. 1.7 ± 2.3). There were no significant differences in the visual analogic pain scores evaluated at any other time between 2 and 72 h after surgery. No significant differences were found in the required doses of tramadol or morphine in the postoperative period. Postoperative hemoglobin and blood loss were also similar in both groups. CONCLUSION: Adding local infiltration of analgesics to peripheral nerve blocks after TKA surgery only provides minimal benefit for pain control. This benefit may be considered as non-clinically relevant. Moreover, the need for additional analgesics was the same in both groups. Therefore, the use of local infiltration of analgesics treatment in TKA surgery cannot be recommended if peripheral nerve blocks are used. LEVEL OF EVIDENCE: I.

Superficial wound infection does not cause inferior clinical outcome after TKA.

PURPOSE: Superficial wound infections do not lead to chronic prosthetic joint infection. Therefore, it has been hypothesized that a superficial infection of a surgical wound following a successfully treated TKA does not lead to a lower functional outcome at long-term follow-up. This may be due to early diagnosis and proper treatment without interrupting the rehabilitation programme. The purpose of this study was to support the hypothesis by comparing the functional outcome and health-related quality of life (HRQoL) of superficial infections treated successfully after primary total knee arthroplasty (TKA). METHODS: In a 3000 prospective TKA cohort, 45 superficial infections were compared to a control group of 629 TKA without complications. The functional outcome, health quality, expectations and revision rate were compared between the study and control groups. RESULTS: The groups were comparable in terms of demographic values and preoperative scores. The mean follow-up was 74.57 months (SD ± 7.1). No statistical differences were observed relative to functional outcomes at the final follow-up as measured with the Knee Society Score (156.9 vs 168.4; n.s) and range of motion (0.2-114.4 vs 0.7-112.3; n.s). For the HRQoL, no differences in the physical (40.0 vs 40.6; n.s) and mental (43.2 vs 45.8; n.s) SF-36 scores were found. Neither were there differences in post-operative expectations and the revision rate. CONCLUSIONS: In a long-term follow-up, a different clinical outcome and HRQoL were not obtained after a successfully treated superficial infection following a TKA when compared to a TKA without complications. Based on the findings of the study, additional complications are not anticipated after a successfully treated superficial wound infection in TKA. Therefore, a different follow-up to that of a non-complicated TKA is not recommended when the early post-operative superficial wound infection has been appropriately treated. A superficial infection successfully treated in the acute post-operative period should be considered solved at long-term follow-up. LEVEL OF EVIDENCE: Therapeutic study, Level III.

Managing septic arthritis after knee ligament reconstruction.

PURPOSE: Joint infection after anterior cruciate ligament (ACL) reconstruction is uncommon but has potentially serious consequences for the graft and articular cartilage. Most recently published series are in agreement that an urgent arthroscopic washout and antibiotic treatment are mandatory to preserve both graft and cartilage. However, several questions have not as yet been touched upon. METHODS: We performed a literature review to assess the most interesting series published about this issue. RESULTS: In this review, a management protocol is first presented that discusses the different diagnostic parameters to consider and surgical and antibiotic treatment suggested according to the literature. Outcomes published in different series are also discussed.