Aims. The aim of this study was to describe the prevalence and patterns of neuropathic pain over one year in a cohort of patients with chronic post-surgical pain at three months following total knee arthroplasty (TKA). Methods. Between 2016 and 2019, 363 patients with troublesome pain, defined as a score of ≤ 14 on the Oxford Knee Score pain subscale, three months after TKA from eight UK NHS hospitals, were recruited into the Support and Treatment After Replacement (STAR) clinical trial. Self-reported neuropathic pain and postoperative pain was assessed at three, nine, and 15 months after surgery using the painDETECT and Douleur Neuropathique 4 (DN4) questionnaires collected by postal survey. Results. Symptoms of neuropathic pain were common among patients reporting chronic pain at three months post-TKA, with half reporting neuropathic pain on painDETECT (191/363; 53%) and 74% (267/359) on DN4. Of those with neuropathic pain at three months, half continued to have symptoms over the next 12 months (148/262; 56%), one-quarter had improved (67/262; 26%), and for one-tenth their neuropathic symptoms fluctuated over time (24/262; 9%). However, a subgroup of participants reported new, late onset neuropathic symptoms (23/262; 9%). Prevalence of neuropathic symptoms was similar between the screening tools when the lower cut-off painDETECT score (≥ 13) was applied. Overall, mean neuropathic pain scores improved between three and 15 months after TKA. Conclusion. Neuropathic pain is common in patients with chronic pain at three months after TKA. Although neuropathic symptoms improved over time, up to half continued to report painful neuropathic symptoms at 15 months after TKA. Postoperative care should include screening, assessment, and treatment of neuropathic pain in patients with early chronic postoperative pain after TKA. Cite this article: Bone Joint J 2024;106-B(6):582–588

Abstract. Introduction. Total knee replacement (TKR) is a successful operation for many patients, however 15–20% of patients experience chronic post-surgical pain (CPSP). Many will experience neuropathic characteristics. We describe the prevalence and patterns of neuropathic pain in a cohort of patients with CPSP three months after TKR. Methodology. Between 2016–2019, 363 patients with troublesome pain, ≤14 on Oxford Knee score pain subscale, at three months after TKR from eight NHS hospitals were recruited into the Support and Treatment After Replacement (STAR) trial. Self-reported neuropathic pain was assessed at three, nine and fifteen months after surgery using painDETECT and Douleur Neuropathique 4 (DN4). Results. At three months post-operative, 53% reported neuropathic pain on painDETECT and 74% on DN4. Half (56%) remained in neuropathic pain over the twelve-month follow-up period, 26% reported improvement, and 9% reported new neuropathic symtpoms or fluctuated in and out of neuropathic pain (9%). Overall mean neuropathic pain scores improved between three and 15 months after TKR. When the painDETECT cut-off score of ≥13(ambiguous/possible) was used, DN4 and painDETECT measures showed similar prevalence rates at each timepoint. Conclusion. Neuropathic pain is common among patients with CPSP at three months after TKR. Although symptoms improved over time, one quarter to one half of our cohort continued to report symptoms at fifteen months. We propose a painDETECT cutoff score of ≥13 be used to identify neuropathic features in the TKR population. Postoperative care should include identification, assessment, and treatment of neuropathic pain in patients with CPSP after TKR

Aims. Despite new technologies for total knee arthroplasty (TKA), approximately 20% of patients are dissatisfied. A major reason for dissatisfaction and revision surgery after TKA is persistent pain. The radiological grade of osteoarthritis (OA) preoperatively has been investigated as a predictor of the outcome after TKA, with conflicting results. The aim of this study was to determine if there is a difference in the intensity of pain 12 months after TKA in relation to the preoperative radiological grade of OA alone, and the combination of the intensity of preoperative pain and radiological grade of OA. Methods. The preoperative data of 300 patients who underwent primary TKA were collected, including clinical information (age, sex, preoperative pain), psychological variables (depression, anxiety, pain catastrophizing, anticipated pain), and quantitative sensory testing (temporal summation, pressure pain thresholds, conditioned pain modulation). The preoperative radiological severity of OA was graded according to the Kellgren-Lawrence (KL) classification. Persistent pain in the knee was recorded 12 months postoperatively. Generalized linear models explored differences in postoperative pain according to the KL grade, and combined preoperative pain and KL grade. Relative risk models explored which preoperative variables were associated with the high preoperative pain/low KL grade group. Results. Pain 12 months after TKA was not associated with the preoperative KL grade alone. Significantly increased pain 12 months after TKA was found in patients with a combination of high preoperative pain and a low KL grade (p = 0.012). Patients in this group were significantly more likely to be male, younger, and have higher preoperative pain catastrophizing, higher depression, and lower anxiety (all p ≤ 0.05). Conclusion. Combined high preoperative pain and low radiological grade of OA, but not the radiological grade alone, was associated with a higher intensity of pain 12 months after primary TKA. This group may have a more complex cause of pain that requires additional psychological interventions in order to optimize the outcome of TKA. Cite this article: Bone Joint J 2022;104-B(11):1202–1208

Abstract. Background. Around 5–15% of patients will experience chronic postoperative pain after total knee replacement (TKR) surgery but the source of the pain is unknown. The aim of this study was to assesses patients six months after TKR using magnetic resonance imaging (MRI) of the knee, pain sensory profiles and assessments of pain catastrophizing thoughts. Methods. Forty-six patients had complete postoperative data and were included. MRI findings were scored according to the MRI Osteoarthritis Knee Score (MOAKS) recommendation for Hoffa synovitis, effusion size and bone marrow lesions. Pain sensory profiles included the assessment of pressure pain thresholds (PPTs), temporal summation of pain (TSP) and conditioned pain modulation (CPM). Pain catastrophizing was assessed using the pain catastrophizing scale (PCS). Clinical pain was evaluated using a visual analog scale (VAS, 0–10cm) and groups of moderate-to-severe (VAS>3) and non-to-mild postoperative pain (VAS≤3) were identified. Results. Patients with moderate-to-severe postoperative pain demonstrated higher grades of Hoffa synovitis (P<0.001) and effusion size (P<0.001), lower PPTs (P=0.039), higher TSP (P=0.001) and lower CPM (P=0.014) when compared to patients with non-to-mild postoperative pain. No differences were found in PCS scores. Linear regression models found TSP (P=0.013), PCS (P<0.001), Hoffa synovitis (P=0.036) and effusion size (P=0.003) as independent parameters contributing to the postoperative pain severity. Conclusion. These finding indicate that chronic postoperative after TKR is a combination of joint-related synovitis and effusion in combination with sensitization of central pain mechanisms and pain catastrophizing thoughts

Aims. The aim was to assess whether robotic-assisted total knee arthroplasty (rTKA) had greater knee-specific outcomes, improved fulfilment of expectations, health-related quality of life (HRQoL), and patient satisfaction when compared with manual TKA (mTKA). Methods. A randomized controlled trial was undertaken (May 2019 to December 2021), and patients were allocated to either mTKA or rTKA. A total of 100 patients were randomized, 50 to each group, of whom 43 rTKA and 38 mTKA patients were available for review at 12 months following surgery. There were no statistically significant preoperative differences between the groups. The minimal clinically important difference in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score was defined as 7.5 points. Results. There were no clinically or statistically significant differences between the knee-specific measures (WOMAC, Oxford Knee Score (OKS), Forgotten Joint Score (FJS)) or HRQoL measures (EuroQol five-dimension questionnaire (EQ-5D) and EuroQol visual analogue scale (EQ-VAS)) at 12 months between the groups. However, the rTKA group had significantly (p = 0.029) greater improvements in the WOMAC pain component (mean difference 9.7, 95% confidence interval (CI) 1.0 to 18.4) over the postoperative period (two, six, and 12 months), which was clinically meaningful. This was not observed for function (p = 0.248) or total (p = 0.147) WOMAC scores. The rTKA group was significantly (p = 0.039) more likely to have expectation of ‘Relief of daytime pain in the joint’ when compared with the mTKA group. There were no other significant differences in expectations met between the groups. There was no significant difference in patient satisfaction with their knee (p = 0.464), return to work (p = 0.464), activities (p = 0.293), or pain (p = 0.701). Conclusion. Patients undergoing rTKA had a clinically meaningful greater improvement in their knee pain over the first 12 months, and were more likely to have fulfilment of their expectation of daytime pain relief compared with patients undergoing mTKA. However, rTKA was not associated with a clinically significant greater knee-specific function or HRQoL, according to current definitions. Cite this article: Bone Joint J 2024;106-B(5):450–459

Abstract. Introduction. Adverse reactions to pain medication and pain can delay discharge after outpatient knee arthroplasty (TKA). Pharmacogenomics is an emerging tool that might help reduce adverse events by tailoring medication use based on known genetic variations in the CYP genes determining drug metabolism. This study was undertaken to evaluate whether pre-operative pharmacogenomic testing could optimize peri-operative pain management in patients undergoing total knee arthroplasty (TKA). Methods. This prospective, randomized study was performed in adults undergoing primary TKA. Patients in the experimental group underwent pre-operative pharmacogenomic evaluation and medication adjustments. Medications were not optimized for control patients. The Overall Benefit of Analgesic Score (OBAS) at 24 hours post-op was the primary outcome. Postoperative pain scores (VAS scale), total opioid use, time in recovery, and time to discharge were also compared. Results. 76 patients enrolled. 93% of patients had a poor-intermediate phenotype for at least one of four CYP genes. OBAS did not differ significantly between the two groups (4.2 control vs. 4.7 experimental; 95% CI −1.1 to 2.1) and was below the minimum clinically important difference of 2.0 points. Furthermore, there were no differences in any OBAS subscale including pain, satisfaction, or nausea. There were no differences in time in the recovery area or to discharge from hospital, or narcotic use. Conclusions. Despite many patients having a poor-intermediate phenotype for a CYP gene, pharmacogenomic testing prior to TKA and medication adjustment did not improve anesthesia or pain management outcomes, time to discharge or mean total opioid use after surgery

Abstract. Introduction. Approximately 15–20% of patients report chronic pain three months after total knee replacement (TKR). The STAR care pathway is a clinically important and cost-effective personalised intervention for patients with pain 3 months after TKR. The pathway comprises screening, assesment, onward referral for treatment and follow-up over one year. In a multicentre randomised controlled trial comparing the pathway with usual care, the pathway improved pain at 6 and 12 months. This study examined the longer-term clinical and cost-effectiveness of the STAR care pathway. Methodology. STAR trial participants were followed-up at a median of 4 years post-randomisation. Co-primary outcomes were self-reported pain severity and interference in the replaced knee, assessed with the Brief Pain Inventory (BPI). Resource use from electronic hospital records was valued with UK reference costs. Results. Of the 337 participants active at trial completion, 326 had confirmed vital status, and 226 (69%) provided outcome data at a median of 4 years. The between-group difference in mean BPI severity score was −0.42 (95% CI −1.07, 0.23; p=0.20) and for BPI interference was −0.64 (95% CI −1.41, 0.12; p=0.10), favouring the intervention. Multiple imputation analyses led to attenuations of about 0.2 points. Mean hospital admission costs over four years were £2461.49 (95% CI £1354.42, £3568.57) in the intervention arm and £3791.68 (95% CI £2095.12, to £5488.24) in usual care. Conclusion. These data are consistent with sustained benefits from the STAR care pathway at 4 years, albeit attenuated and with wider confidence intervals, in part attributable to attrition after 1 year

Aims. The aim of this study was to describe and compare joint-specific and generic health-related quality of life outcomes of the first versus second knee in patients undergoing staged bilateral total knee arthroplasty (BTKA) for osteoarthritis. Methods. This retrospective cohort study used Australian national arthroplasty registry data from January 2013 to January 2021 to identify participants who underwent elective staged BTKA with six to 24 months between procedures. The primary outcome was Oxford Knee Score (OKS) at six months postoperatively for the first TKA compared to the second TKA, adjusted for age and sex. Secondary outcomes compared six-month EuroQol five-dimension five-level (EQ-5D-5L) domain scores, EQ-5D index scores, and the EQ visual analogue scale (EQ-VAS) between knees at six months postoperatively. Results. The cohort included 635 participants (1,270 primary procedures). Preoperative scores were worse in the first knee compared to the second for all instruments; however, comparing the first knee at six months postoperatively with the second knee at six months postoperatively, the mean between-knee difference was minimal for OKS (-0.8 points; 95% confidence interval (CI) -1.4 to -0.2), EQ-VAS (3.3; 95% CI 1.9 to 4.7), and EQ-5D index (0.09 points; 95% CI 0.07 to 0.12). Outcomes for the EQ-5D-5L domains ‘mobility’, ‘usual activities’, and ‘pain/discomfort’ were better following the second TKA. Conclusion. At six months postoperatively, there were no clinically meaningful differences between the first and second TKA in either the joint-specific or overall generic health-related quality of life outcomes. However, individual domain scores assessing mobility, pain, and usual activities were notably higher after the second TKA, likely reflecting the cumulative improvement in quality of life after both knees have been replaced. Cite this article: Bone Jt Open 2024;5(3):202–209

Aims. Stemmed tibial components are frequently used in revision total knee arthroplasty (TKA). The purpose of this study was to evaluate patient satisfaction, overall pain, and diaphyseal tibial pain in patients who underwent revision TKA with cemented or uncemented stemmed tibial components. Methods. This is a retrospective cohort study involving 110 patients with revision TKA with cemented versus uncemented stemmed tibial components. Patients who underwent revision TKA with stemmed tibial components over a 15-year period at a single institution with at least two-year follow-up were assessed. Pain was evaluated through postal surveys. There were 63 patients with cemented tibial stems and 47 with uncemented stems. Radiographs and Knee Society Scores were used to evaluate for objective findings associated with pain or patient dissatisfaction. Postal surveys were analyzed using Fisher’s exact test and the independent-samples t-test. Logistic regression was used to adjust for age, sex, and preoperative bone loss. Results. No statistically significant differences in stem length, operative side, or indications for revision were found between the two cohorts. Tibial pain at the end of the stem was present in 25.3% (16/63) of cemented stems and 25.5% (12/47) of uncemented stems (p = 1.000); 74.6% (47/63) of cemented patients and 78.7% (37/47) of uncemented patients were satisfied following revision TKA (p = 0.657). Conclusion. There were no differences in patient satisfaction, overall pain, and diaphyseal tibial pain in cemented and uncemented stemmed tibial components in revision TKA. Patient factors, rather than implant selection and surgical technique, likely play a large role in the presence of postoperative pain. Stemmed tibial components have been shown to be a possible source of pain in revision TKA. There is no difference in patient satisfaction or postoperative pain with cemented or uncemented stemmed tibial components in revision TKA. Cite this article: Bone Joint J 2021;103-B(6 Supple A):165–170

We identified a group of patients from the Swedish Arthroplasty Register who reported no relief of pain or worse pain one year after a total knee replacement (TKR). A total of two different patient-reported pain scores were used during this process. We then evaluated how the instruments used to measure pain affected the number of patients who reported no relief of pain or worse pain, and the relative effect of potential risk factors. . Between 2008 and 2010, 2883 TKRs were performed for osteoarthritis in two Swedish arthroplasty units. After applying exclusion criteria, 2123 primary TKRs (2123 patients) were included in the study. The Knee injury and Osteoarthritis Outcome Score (KOOS) and a Visual Analogue Scale (VAS) for knee pain were used to assess patients pre-operatively and one year post-operatively. . Only 50 of the 220 patients (23%) who reported no pain relief on either the KOOS pain subscale or the VAS for knee pain did so with both of these instruments. Patients who reported no pain relief on either measure tended to have less pain pre-operatively but a higher degree of anxiety. Charnley category C was a predictor for not gaining pain relief as measured on a VAS for knee pain. . The number of patients who are not relieved of pain after a TKR differs considerably depending on the instrument used to measure pain. . Cite this article: Bone Joint J 2014;96-B:1222–6

Aims. Total knee arthroplasty (TKA) may provoke ankle symptoms. The aim of this study was to validate the impact of the preoperative mechanical tibiofemoral angle (mTFA), the talar tilt (TT) on ankle symptoms after TKA, and assess changes in the range of motion (ROM) of the subtalar joint, foot posture, and ankle laxity. Methods. Patients who underwent TKA from September 2020 to September 2021 were prospectively included. Inclusion criteria were primary end-stage osteoarthritis (Kellgren-Lawrence stage IV) of the knee. Exclusion criteria were missed follow-up visit, post-traumatic pathologies of the foot, and neurological disorders. Radiological angles measured included the mTFA, hindfoot alignment view angle, and TT. The Foot Function Index (FFI) score was assessed. Gait analyses were conducted to measure mediolateral changes of the gait line and ankle laxity was tested using an ankle arthrometer. All parameters were acquired one week pre- and three months postoperatively. Results. A total of 69 patients (varus n = 45; valgus n = 24) underwent TKA and completed the postoperative follow-up visit. Of these, 16 patients (23.2%) reported the onset or progression of ankle symptoms. Varus patients with increased ankle symptoms after TKA had a significantly higher pre- and postoperative TT. Valgus patients with ankle symptoms after TKA showed a pathologically lateralized gait line which could not be corrected through TKA. Patients who reported increased ankle pain neither had a decreased ROM of the subtalar joint nor increased ankle laxity following TKA. The preoperative mTFA did not correlate with the postoperative FFI (r = 0.037; p = 0.759). Conclusion. Approximately one-quarter of the patients developed ankle pain after TKA. If patients complain about ankle symptoms after TKA, standing radiographs of the ankle and a gait analysis could help in detecting a malaligned TT or a pathological gait. Cite this article: Bone Joint J 2023;105-B(11):1159–1167

Aims. Liposomal bupivacaine (LB) as part of a periarticular injection protocol continues to be a highly debated topic in total knee arthroplasty (TKA). We evaluated the effect of discontinuing the use of LB in a periarticular protocol on immediate postoperative pain scores, opioid consumption, and objective functional outcomes. Methods. On 1 July 2019, we discontinued the use of intraoperative LB as part of a periarticular injection protocol. A consecutive group of patients who received LB as part of the protocol (Protocol 1) and a subsequent group who did not (Protocol 2) were compared. All patients received the same opioid-sparing protocol. Verbal rating scale (VRS) pain scores were collected from our electronic data warehouse and averaged per patient per 12-hour interval. Events relating to the opiate administration were derived as morphine milligram equivalences (MMEs) per patient per 24-hour interval. The Activity Measure for Post-Acute Care (AM-PAC) tool was used to assess the immediate postoperative function. Results. A total of 888 patients received Protocol 1 and while 789 received Protocol 2. The mean age of the patients was significantly higher in those who did not receive LB (66.80 vs 65.57 years, p = 0.006). The sex, BMI, American Society of Anesthesiologists physical status score, race, smoking status, marital status, operating time, length of stay, and discharge disposition were similar in the two groups. Compared with the LB group, discontinuing LB showed no significant difference in postoperative VRS pain scores up to 72 hours (p > 0.05), opioid administration up to 96 hours (p > 0.05), or AM-PAC scores within the first 24 hours (p > 0.05). Conclusion. The control of pain after TKA with a multimodal management protocol is not improved by the addition of LB compared with traditional bupivacaine. Cite this article: Bone Joint J 2021;103-B(6 Supple A):102–107

Aims. The purpose of this study was to use pharmacogenetics to determine the frequency of genetic variants in our total knee arthroplasty (TKA) patients that could affect postoperative pain medications. Pharmacogenetic testing evaluates patient DNA to determine if a drug is expected to have a normal clinical effect, heightened effect, or no effect at all on the patient. It also predicts whether patients are likely to experience side effects from medicine. We further sought to determine if changing the multimodal programme based on these results would improve pain control or reduce side effects. Methods. In this pilot study, buccal samples were collected from 31 primary TKA patients. Pharmacogenetics testing examined genetic variants in genes OPRM1, CYP1A2, CYP2B6, CYP2C19, CYP3A4, CYP2C9, and CYP2D6. These genes affect the pharmacodynamics and pharmacokinetics of non-steroidal anti-inflammatory drugs and opioids. We examined the frequency of genetic variants to any of the medications we prescribed including celecoxib, hydrocodone, and tramadol. Patients were randomized to one of two groups: the control group received the standard postoperative pain regimen, and the study group received a customized regimen based on the pharmacogenetic results. For the first ten postoperative days, patients recorded pain scores, medication, and side effects. Results. Genetic variants involving one or more medications in the multimodal pain protocol occurred in 13 of the 31 patients (42%). In total, eight patients (26%) had variants affecting more than one of the medications. For the 25 patients who recorded pain and medication logs, the mean pain levels and morphine equivalents (MEQs) consumed in the first ten days were higher in the control group than in the custom-guided group (p = 0.019 for pain and p = 0.655 for MEQ). Conclusion. Overall, 42% of patients had a variant involving one of the pain medications prescribed in our perioperative pain program for TKA. Ongoing research will help determine if using these data to modify a patient’s medication will improve outcomes. Cite this article: Bone Joint J 2020;102-B(6 Supple A):73–78

Abstract. Objectives. To determine the effectiveness of LIA compared to ACB in providing pain relief and reducing opiates usage in hamstring graft ACL reconstructions. Materials and Methods. In a consecutive series of hamstring graft ACL reconstructions, patients received three different regional and/or anaesthetic techniques for pain relief. Three groups were studied: group 1: general anaesthetic (GA)+ ACB (n=38); group 2: GA + ACB + LIA (n=31) and group 3: GA+LIA (n=36). ACB was given under ultrasound guidance. LIA involved infiltration at skin incision site, capsule, periosteum and in the hamstring harvest tunnel. Analgesic medications were similar between the three groups as per standard multimodal analgesia (MMA). Patients were similar in demographics distribution and surgical technique. The postoperative pain and total morphine requirements were evaluated and recorded. The postoperative pain was assessed using the visual analogue scores (VAS) at 0hrs, 2hrs, 4hrs, weight bearing (WB) and discharge (DC). Results. There was no statistically significant difference in opiates intake amongst the three groups. When comparing VAS scores; there were no statistical difference between the groups at any of the time intervals that VAS was measured. However, the GA+LIA group hospital's LOS (m=2.31hrs, SD=0.75) was almost half that of GA+ACB group (m=4.24hrs, SD=1.08); (conditions t(72)=8.88; p=0.000). There was no statistical significance in the incidence of adverse effects amongst the groups. Conclusion. The LIA technique provided equally good pain relief following hamstring graft ACL reconstructions when compared to ACB, while allowing for earlier rehabilitation, mobilisation and discharge

Introduction. Revision total knee arthroplasty (TKA) is becoming increasingly common in the United States as the population ages and larger numbers of primary TKA are performed in younger individuals. Cemented or uncemented tibial stems are frequently used in revision cases. Decreased clinical outcomes and patient satisfaction have been described for revision TKA. This study aims to determine if the presence of overall pain and tibial pain at the end of the stem differs between cemented and uncemented tibial stems in revision TKA. Methods. This was a retrospective cohort study comparing patients who underwent revision TKA utilizing cemented or uncemented tibial stems in a 15-year period at a single institution with at least two-year follow-up. Exclusion criteria included age under 18, isolated revisions of the femoral component or polyethylene exchanges, lack of preoperative or postoperative imaging, insufficient operative or implant records available for electronic chart review, revision procedures performed at outside facilities, patients who were deceased at the time of survey administration, refusal to participate in the study, and failure to return the mailed survey or respond to a telephone follow-up questionnaire. Radiographic analysis included calculation of the percentage of the tibial canal filled with the implant, as well as measurement of the diameter of the tibial stem. Radiographs were also reviewed for evidence of cavitary defects, pedestal formation, radiolucent lines, and periprosthetic fractures. Mailed surveys addressing overall pain, tibial pain, and satisfaction were analyzed using Fisher's exact test and the independent sample t-test. Logistic regression was used to adjust for age, gender, and preoperative bone loss. Results. A total of 110 patients were included (63 cemented and 47 uncemented stems). No statistically significant differences in stem length, operative side, or indications for revision were found. The uncemented group had a significantly higher percent canal fill (p < 0.0001). Tibial pain at the end of the stem was present in 25.3% of cemented stems and 25.5% of uncemented stems (p = 1.00). There was a trend towards more overall pain in the uncemented cohort, but this did not reach statistical significance. Only 74.6% of cemented patients and 78.7% of uncemented patients were satisfied following revision TKA (p = 0.66). Conclusion. The data supports our hypothesis that there are no differences in end-of-stem pain or overall pain between cemented and uncemented tibial stems in revision TKA. High rates of dissatisfaction were noted in both cohorts postoperatively, consistent with previous literature. Patient factors likely play a large role in the presence of postoperative pain. These factors should be further evaluated in future studies in an effort to reduce pain and improve patient satisfaction

Introduction. The commonest causes of revision of Unicompartmental Knee Replacement (UKR) in National Registers are loosening and pain. Cementless UKR was introduced to address loosening and was found, in small randomised studies, to have better radiographic fixation than Cemented UKR. Although non-significant these studies also suggested the clinical outcome was better with cementless. The aim of this larger study was to compare the pain and function of cementless and cemented UKR at five years. Methods. 263 Cemented and 266 Cementless UKR of identical design, implanted by four high volume surgeons for the same indications, were reviewed by independent physiotherapists at five years. Revision, re-operation, Oxford Knee Score (OKS), American Knee Society score (AKSS) and EQ-5D were assessed. Two pain specific scores were also used: Pain Detect (PD) and Intermittent and Constant Osteoarthritis Pain (ICOAP). The pain scores were normalised onto a scale of 0 to 100 with 100 being the best. The cemented cohort was mainly implanted before the cementless, although there was considerable overlap. To explore whether differences were due to progressive improvement in surgical practice with time each cohort was divided into early and late subgroups. Results. Pre-operatively there were no differences between the devices in patient demographics or scores. At 5 years there were no differences in revision rate (0.8%), re-operation rate (2.2%) or medical complication rate (4%). The Cementless had significantly (p<0.05) better OKS (43 v 41), AKSS and EQ5D. There were significantly (p=0.03) fewer cementless cases with unexplained pain (2.3% v 6%). The cementless had significantly (p<0.002), less ‘strongest’ (84 v 76) and ‘average’ (90 v 85) pain as assessed by PD and less chronic (97 v 92) and intermittent (93 v 86) pain as assessed by ICOAP. Subgroup analysis found no significant differences in outcome between the early and late subgroups within the cohorts, whereas there were significant differences in outcomes between the late subgroup of the cemented cohort and the early subgroup of the cementless cohort. Discussion and Conclusion. Almost all outcome scores were significantly better following cementless compared to cemented UKR, suggesting that the cementless is better than cemented. However, as the cemented cases were mainly implanted before the cementless, it could be the difference was due to other factors, such as surgical technique or rehabilitation, that improved with time. This is unlikely to be the case as there were no differences between the early and late subgroups within the cohorts whereas there were differences between the late subgroup of the cemented cohort and the early subgroup of the cementless cohort which were implanted at a similar time. Although the functional scores following cementless are significantly better than cemented, the differences are similar to or smaller than the minimally clinical important difference (MCID) for these scores. In contrast there is significantly less pain following the cementless and the differences tended to be greater than the MCID. This suggests that Cementless UKR is associated with appreciably less pain and slightly better function than Cemented UKR. For figures, tables, or references, please contact authors directly

Introduction. Knee arthroplasty (KA) is a highly effective surgical procedure. However, research suggests that a considerable number of patients continue to experience substantial pain and functional loss following surgical recovery. We aimed to estimate pain and function outcome trajectories for persons undergoing KA depicting the outcome, the relationship between the pain and function trajectory types, and pre-surgery predictors of trajectory type (i.e., good versus poor). Methods. Participants included 384 patients who took part in the Knee Arthroplasty Skills Training (KASTPain) clinical trial. Pain and function was assessed at 2-week pre- and 2-, 6-, and 12-month post-surgery using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Pain and Function Scales. Piecewise latent class growth models were used to estimate pain and function trajectories. Dumenci's latent kappa was used to estimate the chance-corrected agreement between pain and function trajectory types. Pre-surgery variables were used to predict trajectory types. Results. There was strong evidence for two trajectory types, labeled as good and poor, for both WOMAC pain and function scores. Model estimated rates of the poor trajectory type were 18% for both pain and function. Dumenci's latent kappa between pain and function trajectory types was 0.71 (95% CI: 0.61 – 0.80). Most pre-surgery variables were not significant predictors of the trajectory types. Conclusions. Among adults with moderate to severe pain catastrophizing undergoing KA, approximately one-fifth of patients continue to have persistent pain, poor function, or both, which is similar to the rate of poor reported outcomes in the TKA population overall. Although the poor pain and function trajectory types tend to go together within persons, a significant number of patients experience either poor pain or function but not both, suggesting heterogeneity among persons who do not fully benefit from KA. For figures, tables, or references, please contact authors directly

Introduction. Even as the outcomes of primary total knee arthroplasty (TKA) continue to improve, there remain increasing concerns about pain control after surgery and prolonged narcotic use. Cryoneurolysis has been demonstrated to reduce osteoarthritis knee pain for up to 90 days. We hypothesized that postoperative narcotic use could be reduced following preoperative cryoneurolysis of the superficial genicular nerves. Methods. Primary TKA patients were randomized into either a control or cryoneurolysis treatment group. Both followed the same preoperative, intraoperative, and postoperative pain management protocol, except the treatment group had cryoneurolysis of their superficial genicular nerves 3–7 days prior to surgery. All patients were prescribed 40 narcotic pills at discharge and pills were counted at 72 hours and at 2,6, and 12 weeks postoperatively. The primary endpoint was daily morphine equivalent (DME) based on pill count and secondary endpoints were changes in pain and Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS, Jr.) scores. Results. Per-protocol results demonstrated that the DME for the treatment group was significantly lower at 72 hours (10.9 mg vs. 14.9 mg, p=0.0389), 6 weeks (4.2 mg vs. 5.9 mg, p=0.0186) and 12 weeks (2.4 mg vs 3.4 mg p=0.0234). Overall, there was a 29% reduction in the DMEs over the entire 12-week postoperative period. Only 14% of the treatment group consumed opioids past 6 weeks compared to 44% of the control group (p=0.0005). The treatment group demonstrated a greater reduction in pain scores from baseline at 72 hours and 12 weeks. The treatment group also showed significant improvements in KOOS Jr. scores compared to the control group at all timepoints. Conclusions. The results demonstrate that preoperative cryoneurolysis can reduce opioid consumption after TKA. The early cessation of opioid consumption is especially encouraging given the association of prolonged narcotic use with increased complications following surgery. Preoperative cryoneurolysis should be considered as part of a multimodal protocol to reduce opioid consumption and pain and improve function after TKA. For figures, tables, or references, please contact authors directly

Aims. The aim of this study was to examine whether tourniquet use can improve perioperative blood loss, early function recovery, and pain after primary total knee arthroplasty (TKA) in the setting of multiple-dose intravenous tranexamic acid. Methods. This was a prospective, randomized clinical trial including 180 patients undergoing TKA with multiple doses of intravenous tranexamic acid. One group was treated with a tourniquet during the entire procedure, the second group received a tourniquet during cementing, and the third group did not receive a tourniquet. All patients received the same protocol of intravenous tranexamic acid (20 mg/kg) before skin incision, and three and six hours later (10 mg/kg). The primary outcome measure was perioperative blood loss. Secondary outcome measures were creatine kinase (CK), CRP, interleukin-6 (IL-6), visual analogue scale (VAS) pain score, limb swelling ratio, quadriceps strength, straight leg raising, range of motion (ROM), American Knee Society Score (KSS), and adverse events. Results. The mean total blood loss was lowest in the no-tourniquet group at 867.32 ml (SD 201.11), increased in the limited-tourniquet group at 1024.35 ml (SD 176.35), and was highest in the tourniquet group at 1,213.00 ml (SD 211.48). The hidden blood loss was lowest in the no-tourniquet group (both p < 0.001). There was less mean intraoperative blood loss in the tourniquet group (77.48 ml (SD 24.82)) than in the limited-tourniquet group (137.04 ml (SD 26.96)) and the no-tourniquet group (212.99 ml (SD 56.35); both p < 0.001). Patients in the tourniquet group showed significantly higher levels of muscle damage and inflammation biomarkers such as CK, CRP, and IL-6 than the other two groups (p < 0.05). Outcomes for VAS pain scores, limb swelling ratio, quadriceps strength, straight leg raising, ROM, and KSS were significantly better in the no-tourniquet group at three weeks postoperatively (p < 0.05), but there were no significant differences at three months. No significant differences were observed among the three groups with respect to transfusion rate, thrombotic events, or the length of hospital stay. Conclusion. Patients who underwent TKA with multiple doses of intravenous tranexamic acid but without a tourniquet presented lower total blood loss and hidden blood loss, and they showed less postoperative inflammation reaction, less muscle damage, lower VAS pain score, and better early knee function. Our results argue for not using a tourniquet during TKA. Cite this article: Bone Joint Res 2020;9(6):322–332

Aims. Robotic-assisted total knee arthroplasty (RA-TKA) has been introduced to provide accurate bone cuts and help achieve the target knee alignment, along with symmetric gap balancing. The purpose of this study was to determine if any early clinical benefits could be realized following TKA using robotic-assisted technology. Methods. In all, 140 consecutive patients undergoing RA-TKA and 127 consecutive patients undergoing conventional TKA with minimum six-week follow-up were reviewed. Differences in visual analogue scores (VAS) for pain at rest and with activity, postoperative opiate usage, and length of stay (LOS) between the RA-TKA and conventional TKA groups were compared. Results. Patients undergoing RA-TKA had lower average VAS pain scores at rest (p = 0.001) and with activity (p = 0.03) at two weeks following the index procedure. At the six-week interval, the RA-TKA group had lower VAS pain scores with rest (p = 0.03) and with activity (p = 0.02), and required 3.2 mg less morphine equivalents per day relative to the conventional group (p < 0.001). At six weeks, a significantly greater number of patients in the RA-TKA group were free of opioid use compared to the conventional TKA group; 70.7% vs 57.0% (p = 0.02). Patients in the RA-TKA group had a shorter LOS; 1.9 days versus 2.3 days (p < 0.001), and also had a greater percentage of patient discharged on postoperative day one; 41.3% vs 20.5% (p < 0.001). Conclusion. Patients undergoing RA-TKA had lower pain levels at both rest and with activity, required less opioid medication, and had a shorter LOS