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Background. The evaluation and management of outcomes risk has become an essential element of a modern total joint replacement program. Our multidisciplinary team designed an evidence-based tool to address modifiable risk factors for adverse outcomes after primary hip and knee arthroplasty surgery. Methods. Our protocols were designed to identify, intervene, and mitigate risk through evidence-based patient optimization. Nurse navigators screened patients preoperatively, identified and treated risk factors, and followed patients for 90 days postoperatively. We compared patients participating in our optimization program (N=104) to both a historical cohort (N=193) and a contemporary cohort (N=166). Results. Risk factor identification and optimization resulted in lower hospital length of stay and post-operative emergency department visits. Patients in the optimization cohort had a statistically significant decrease in mean LOS as compared to both the historical cohort (2.55 vs 1.81 days, P<0.001) and contemporary cohort (2.56 vs 1.81 days, p<0.001). Patients in the optimization cohort had a statistically significant decrease in 30- and 90-day ED visits compared to the historical cohort (P. 30-day. =0.042, P. 90-day. =0.003). When compared with the contemporary cohort, the optimization cohort had a statistically significant decrease in 90-day ED visits (21.08% vs. 10.58%, P=0.025). The optimization cohort had a statistically significant increase in the percentage of patients discharged home. We noted nonsignificant reductions in readmission rate, transfusion rate, and surgical site infections. Conclusion. Optimization of patients prior to elective primary THA and TKA reduced average LOS, ED visits, and drove tele-rehabilitation use. Our results add to the limited body of literature supporting this patient-centered approach


Bone & Joint Open
Vol. 4, Issue 6 | Pages 399 - 407
1 Jun 2023
Yeramosu T Ahmad W Satpathy J Farrar JM Golladay GJ Patel NK

Aims. To identify variables independently associated with same-day discharge (SDD) of patients following revision total knee arthroplasty (rTKA) and to develop machine learning algorithms to predict suitable candidates for outpatient rTKA. Methods. Data were obtained from the American College of Surgeons National Quality Improvement Programme (ACS-NSQIP) database from the years 2018 to 2020. Patients with elective, unilateral rTKA procedures and a total hospital length of stay between zero and four days were included. Demographic, preoperative, and intraoperative variables were analyzed. A multivariable logistic regression (MLR) model and various machine learning techniques were compared using area under the curve (AUC), calibration, and decision curve analysis. Important and significant variables were identified from the models. Results. Of the 5,600 patients included in this study, 342 (6.1%) underwent SDD. The random forest (RF) model performed the best overall, with an internally validated AUC of 0.810. The ten crucial factors favoring SDD in the RF model include operating time, anaesthesia type, age, BMI, American Society of Anesthesiologists grade, race, history of diabetes, rTKA type, sex, and smoking status. Eight of these variables were also found to be significant in the MLR model. Conclusion. The RF model displayed excellent accuracy and identified clinically important variables for determining candidates for SDD following rTKA. Machine learning techniques such as RF will allow clinicians to accurately risk-stratify their patients preoperatively, in order to optimize resources and improve patient outcomes. Cite this article: Bone Jt Open 2023;4(6):399–407


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_9 | Pages 46 - 46
1 Oct 2020
Wilkie WA Salem HS Remily E Mohamed NS Scuderi GR Mont MA Delanois RE
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Introduction. Social determinants of health (SDOH) may contribute markedly to the total cost of care (COC) for patients undergoing elective total knee arthroplasty (TKA). This study investigated the association between demographics, health status, and SDOH on lengths of stay (LOS) and 30-day COC. Methods. Patients who underwent TKA between January 2018 and December 2019 were identified. Those who had complete SDOH data were utilized, leaving 234 patients. Data elements were drawn from the Chesapeake Regional Information System, the Center for Disease Control social vulnerability index (SVI), the Food Access Research Atlas (FARA). The SVI identifies areas vulnerable to catastrophic events, with 4 themed scores including: (1) socioeconomic status; (2) household composition and disability; (3) minority status and language; and (4) housing and transportation. Food deserts were defined as neighborhoods located 1 or 10 miles from a grocery store in urban and rural areas, respectively. Multiple regression analyses were performed to determine an association with LOS and cost, after controlling for demographics. Results. Increased 30-day COC associated with SVI theme 3, (3.074 days; p=0.001) and patients who lived in a food desert ($53,205; p=0.001), as well as those who had anemia ($16,112; P = 0.038), chronic obstructive pulmonary disease ($32,570, P = 0.001), congestive heart failure ($30,927, P = 0.003), and dementia ($33,456, P = 0.008). Longer hospital lengths of stay were associated with SVI theme 3. In addition, patients who had anemia and congestive heart failure were at risk for longer hospital lengths of stay (P < 0.001, P = 0.001, respectively). Conclusion. Higher SVI theme 3 scores and living in food deserts were risk factors for increased LOS and costs, respectively. Identifying social factors including a patient's transportation options, living situation and access to healthy foods may prove to be both prognostic of outcomes and an opportunity for intervention


The Bone & Joint Journal
Vol. 103-B, Issue 8 | Pages 1358 - 1366
2 Aug 2021
Wei C Quan T Wang KY Gu A Fassihi SC Kahlenberg CA Malahias M Liu J Thakkar S Gonzalez Della Valle A Sculco PK

Aims. This study used an artificial neural network (ANN) model to determine the most important pre- and perioperative variables to predict same-day discharge in patients undergoing total knee arthroplasty (TKA). Methods. Data for this study were collected from the National Surgery Quality Improvement Program (NSQIP) database from the year 2018. Patients who received a primary, elective, unilateral TKA with a diagnosis of primary osteoarthritis were included. Demographic, preoperative, and intraoperative variables were analyzed. The ANN model was compared to a logistic regression model, which is a conventional machine-learning algorithm. Variables collected from 28,742 patients were analyzed based on their contribution to hospital length of stay. Results. The predictability of the ANN model, area under the curve (AUC) = 0.801, was similar to the logistic regression model (AUC = 0.796) and identified certain variables as important factors to predict same-day discharge. The ten most important factors favouring same-day discharge in the ANN model include preoperative sodium, preoperative international normalized ratio, BMI, age, anaesthesia type, operating time, dyspnoea status, functional status, race, anaemia status, and chronic obstructive pulmonary disease (COPD). Six of these variables were also found to be significant on logistic regression analysis. Conclusion. Both ANN modelling and logistic regression analysis revealed clinically important factors in predicting patients who can undergo safely undergo same-day discharge from an outpatient TKA. The ANN model provides a beneficial approach to help determine which perioperative factors can predict same-day discharge as of 2018 perioperative recovery protocols. Cite this article: Bone Joint J 2021;103-B(8):1358–1366


The Bone & Joint Journal
Vol. 101-B, Issue 7_Supple_C | Pages 17 - 21
1 Jul 2019
Schroer WC LeMarr AR Mills K Childress AL Morton DJ Reedy ME

Aims. To date, no study has demonstrated an improvement in postoperative outcomes following elective joint arthroplasty with a focus on nutritional intervention for patients with preoperative hypoalbuminaemia. In this prospective study, we evaluated differences in the hospital length of stay (LOS), rate of re-admission, and total patient charges for a malnourished patient study population who received a specific nutrition protocol before surgery. Patients and Methods. An analytical report was extracted from the electronic medical record (EMR; Epic, Verona, Wisconsin) of a five-hospital network joint arthroplasty patient data set between 2014 and 2017. A total of 4733 patients underwent joint arthroplasty and had preoperative measurement of albumin levels: 2220 at four hospitals and 2513 at the study hospital. Albumin ≤ 3.4 g/l, designated as malnutrition, was found in 543 patients (11.5%). A nutritional intervention programme focusing on a high-protein, anti-inflammatory diet was initiated in January 2017 at one study hospital. Hospital LOS, re-admission rate, and 90-day charges were compared for differential change between patients in study and control hospitals for all elective hip and knee arthroplasty patients, and for malnourished patients over time as the nutrition intervention was implemented. Results. Malnourished patients with nutritional intervention at the study hospital had shorter hospital LOS beginning in 2017 than malnourished patients at control hospitals during the same period (p = 0.04). Similarly, this cohort had significantly lower primary hospitalization charges, charges associated with hospital re-admissions, and 90-day total charges (p < 0.001). Inclusion of covariant potential confounders (age, anaemia, diabetes, and obesity) did not alter the conclusions of the primary statistical analysis. Conclusion. Joint arthroplasty outcomes were positively affected in study patients with low albumin when a high-protein, anti-inflammatory diet was encouraged. Elective surgery was neither cancelled nor delayed with a malnutrition designation. While the entire network population experienced improved postoperative outcomes, malnourished control patients did not experience this improvement. This study demonstrated that education on malnutrition can benefit patients. Cite this article: Bone Joint J 2019;101-B(7 Supple C):17–21


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_11 | Pages 37 - 37
1 Oct 2019
Nahhas CR Chalmers PN Parvizi J Sporer SM Berend KR Moric M Chen AF Austin M Deirmengian GK Morris MJ Culvern C Valle CJD
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Background. The purpose of this multi-center, randomized clinical trial was to compare static and articulating spacers in the treatment of PJI complicating total knee arthroplasty TKA. Methods. 68 Patients treated with two-stage exchange arthroplasty were randomized to either a static (32 patients) or an articulating (36 patients) spacer. A power analysis determined that 28 patients per group were necessary to detect a 13º difference in range of motion between groups. Six patients were excluded after randomization, six died, and seven were lost to follow-up prior to two years. Results. Patients in the static group had a hospital length of stay that was one day greater than the articulating group (6.1 vs. 5.1 days; p=0.032); no other differences were noted perioperatively. At a mean 3.5 years (range, 2.0 to 6.4 years), 49 patients were available for evaluation. Mean motion arc in the articulating group was 113.0º compared to 100.2º in the static group (p=0.001). The mean Knee Society Score was significantly higher in the articulating cohort (79.4 vs. 69.8 points; p=0.043). Although not significantly different with the sample size studied, static spacers were associated with a greater need for an extensile exposure at the time of reimplantation (16.7% vs. 3.8%) and a higher rate of reoperation (33.3% vs. 12.0%). Conclusions. Articulating spacers provided significantly greater range of motion and better clinical outcomes scores. Static spacers also appeared to affect early postoperative rehabilitation, as evidenced by a longer hospital stay following removal of the infected implant and were associated with a trend towards a greater need for extensile exposures at the time of reimplantation. Further, while it has been commonly believed that static spacers would improve infection control, there was no difference in the failure rate secondary to reinfection and there was a trend towards higher risk of reoperation in patients who received a static spacer. When the soft tissue envelope allows and if there is adequate bony support, an articulating spacer is associated with improved outcomes. For figures, tables, or references, please contact authors directly


The Bone & Joint Journal
Vol. 104-B, Issue 12 | Pages 1323 - 1328
1 Dec 2022
Cochrane NH Kim B Seyler TM Bolognesi MP Wellman SS Ryan SP

Aims. In the last decade, perioperative advancements have expanded the use of outpatient primary total knee arthroplasty (TKA). Despite this, there remains limited data on expedited discharge after revision TKA. This study compared 30-day readmissions and reoperations in patients undergoing revision TKA with a hospital stay greater or less than 24 hours. The authors hypothesized that expedited discharge in select patients would not be associated with increased 30-day readmissions and reoperations. Methods. Aseptic revision TKAs in the National Surgical Quality Improvement Program database were reviewed from 2013 to 2020. TKAs were stratified by length of hospital stay (greater or less than 24 hours). Patient demographic details, medical comorbidities, American Society of Anesthesiologists (ASA) grade, operating time, components revised, 30-day readmissions, and reoperations were compared. Multivariate analysis evaluated predictors of discharge prior to 24 hours, 30-day readmission, and reoperation. Results. Of 21,610 aseptic revision TKAs evaluated, 530 were discharged within 24 hours. Short-stay patients were younger (63.1 years (49 to 78) vs 65.1 years (18 to 94)), with lower BMI (32.3 kg/m. 2. (17 to 47) vs 33.6 kg/m. 2. (19 to 54) and lower ASA grades. Diabetes, chronic obstructive pulmonary disease, hypertension, and cancer were all associated with a hospital stay over 24 hours. Single component revisions (56.8% (n = 301) vs 32.4% (n = 6,823)), and shorter mean operating time (89.7 minutes (25 to 275) vs 130.2 minutes (30 to 517)) were associated with accelerated discharge. Accelerated discharge was not associated with 30-day readmission and reoperation. Conclusion. Accelerated discharge after revision TKA did not increase short-term complications, readmissions, or reoperations. Further efforts to decrease hospital stays in this setting should be evaluated. Cite this article: Bone Joint J 2022;104-B(12):1323–1328


Bone & Joint Open
Vol. 4, Issue 5 | Pages 393 - 398
25 May 2023
Roof MA Lygrisse K Shichman I Marwin SE Meftah M Schwarzkopf R

Aims

Revision total knee arthroplasty (rTKA) is a technically challenging and costly procedure. It is well-documented that primary TKA (pTKA) have better survivorship than rTKA; however, we were unable to identify any studies explicitly investigating previous rTKA as a risk factor for failure following rTKA. The purpose of this study is to compare the outcomes following rTKA between patients undergoing index rTKA and those who had been previously revised.

Methods

This retrospective, observational study reviewed patients who underwent unilateral, aseptic rTKA at an academic orthopaedic speciality hospital between June 2011 and April 2020 with > one-year of follow-up. Patients were dichotomized based on whether this was their first revision procedure or not. Patient demographics, surgical factors, postoperative outcomes, and re-revision rates were compared between the groups.


The Bone & Joint Journal
Vol. 105-B, Issue 9 | Pages 971 - 976
1 Sep 2023
Bourget-Murray J Piroozfar S Smith C Ellison J Bansal R Sharma R Evaniew N Johnson A Powell JN

Aims

This study aims to determine difference in annual rate of early-onset (≤ 90 days) deep surgical site infection (SSI) following primary total knee arthroplasty (TKA) for osteoarthritis, and to identify risk factors that may be associated with infection.

Methods

This is a retrospective population-based cohort study using prospectively collected patient-level data between 1 January 2013 and 1 March 2020. The diagnosis of deep SSI was defined as per the Centers for Disease Control/National Healthcare Safety Network criteria. The Mann-Kendall Trend test was used to detect monotonic trends in annual rates of early-onset deep SSI over time. Multiple logistic regression was used to analyze the effect of different patient, surgical, and healthcare setting factors on the risk of developing a deep SSI within 90 days from surgery for patients with complete data. We also report 90-day mortality.


The Bone & Joint Journal
Vol. 104-B, Issue 11 | Pages 1209 - 1214
1 Nov 2022
Owen AR Amundson AW Larson DR Duncan CM Smith HM Johnson RL Taunton MJ Pagnano MW Berry DJ Abdel MP

Aims

Spinal anaesthesia has seen increased use in contemporary primary total knee arthroplasties (TKAs). However, controversy exists about the benefits of spinal in comparison to general anaesthesia in primary TKAs. This study aimed to investigate the pain control, length of stay (LOS), and complications associated with spinal versus general anaesthesia in primary TKAs from a single, high-volume academic centre.

Methods

We retrospectively identified 17,690 primary TKAs (13,297 patients) from 2001 to 2016 using our institutional total joint registry, where 52% had general anaesthesia and 48% had spinal anaesthesia. Baseline characteristics were similar between cohorts with a mean age of 68 years (SD 10), 58% female (n = 7,669), and mean BMI of 32 kg/m2 (SD 7). Pain was evaluated using oral morphine equivalents (OMEs) and numerical pain rating scale (NPRS) data. Complications including 30- and 90-day readmissions were studied. Data were analyzed using an inverse probability of treatment weighted model based on propensity score that included many patient and surgical factors. Mean follow-up was seven years (2 to 18).


Bone & Joint Open
Vol. 4, Issue 5 | Pages 338 - 356
10 May 2023
Belt M Robben B Smolders JMH Schreurs BW Hannink G Smulders K

Aims

To map literature on prognostic factors related to outcomes of revision total knee arthroplasty (rTKA), to identify extensively studied factors and to guide future research into what domains need further exploration.

Methods

We performed a systematic literature search in MEDLINE, Embase, and Web of Science. The search string included multiple synonyms of the following keywords: "revision TKA", "outcome" and "prognostic factor". We searched for studies assessing the association between at least one prognostic factor and at least one outcome measure after rTKA surgery. Data on sample size, study design, prognostic factors, outcomes, and the direction of the association was extracted and included in an evidence map.


The Bone & Joint Journal
Vol. 103-B, Issue 6 Supple A | Pages 113 - 118
1 Jun 2021
Delanois RE Tarazi JM Wilkie WA Remily E Salem HS Mohamed NS Pollack AN Mont MA

Aims

Social determinants of health (SDOHs) may contribute to the total cost of care (TCOC) for patients undergoing total knee arthroplasty (TKA). The aim of this study was to investigate the association between demographic data, health status, and SDOHs on 30-day length of stay (LOS) and TCOC after this procedure.

Methods

Patients who underwent TKA between 1 January 2018 and 31 December 2019 were identified. A total of 234 patients with complete SDOH data were included. Data were drawn from the Chesapeake Regional Information System, the Centers for Disease Control social vulnerability index (SVI), the US Department of Agriculture, and institutional electronic medical records. The SVI identifies areas vulnerable to catastrophic events with four themed scores: socioeconomic status; household composition and disability; minority status and language; and housing and transportation. Food deserts were defined as neighbourhoods located one or ten miles from a grocery store in urban and rural areas, respectively. Multiple regression analyses were performed to determine associations with LOS and costs after controlling for various demographic parameters.


The Bone & Joint Journal
Vol. 103-B, Issue 4 | Pages 635 - 643
1 Apr 2021
Ross LA Keenan OJF Magill M Brennan CM Clement ND Moran M Patton JT Scott CEH

Aims. Debate continues regarding the optimum management of periprosthetic distal femoral fractures (PDFFs). This study aims to determine which operative treatment is associated with the lowest perioperative morbidity and mortality when treating low (Su type II and III) PDFFs comparing lateral locking plate fixation (LLP-ORIF) or distal femoral arthroplasty (DFA). Methods. This was a retrospective cohort study of 60 consecutive unilateral (PDFFs) of Su types II (40/60) and III (20/60) in patients aged ≥ 60 years: 33 underwent LLP-ORIF (mean age 81.3 years (SD 10.5), BMI 26.7 (SD 5.5); 29/33 female); and 27 underwent DFA (mean age 78.8 years (SD 8.3); BMI 26.7 (SD 6.6); 19/27 female). The primary outcome measure was reoperation. Secondary outcomes included perioperative complications, calculated blood loss, transfusion requirements, functional mobility status, length of acute hospital stay, discharge destination and mortality. Kaplan-Meier survival analysis was performed. Cox multivariate regression analysis was performed to identify risk factors for reoperation after LLP-ORIF. Results. Follow-up was at mean 3.8 years (1.0 to 10.4). One-year mortality was 13% (8/60). Reoperation was more common following LLP-ORIF: 7/33 versus 0/27 (p = 0.008). Five-year survival for reoperation was significantly better following DFA; 100% compared to 70.8% (95% confidence interval (CI) 51.8% to 89.8%, p = 0.006). There was no difference for the endpoint mechanical failure (including radiological loosening); ORIF 74.5% (56.3 to 92.7), and DFA 78.2% (52.3 to 100, p = 0.182). Reoperation following LLP-ORIF was independently associated with medial comminution; hazard ratio (HR) 10.7 (1.45 to 79.5, p = 0.020). Anatomical reduction was protective against reoperation; HR 0.11 (0.013 to 0.96, p = 0.046). When inadequately fixed fractures were excluded, there was no difference in five-year survival for either reoperation (p = 0.156) or mechanical failure (p = 0.453). Conclusion. Absolute reoperation rates are higher following LLP fixation of low PDFFs compared to DFA. Where LLP-ORIF was well performed with augmentation of medial comminution, there was no difference in survival compared to DFA. Though necessary in very low fractures, DFA should be used with caution in patients with greater life expectancies due to the risk of longer term aseptic loosening. Cite this article: Bone Joint J 2021;103-B(4):635–643


Bone & Joint Research
Vol. 9, Issue 1 | Pages 15 - 22
1 Jan 2020
Clement ND Bell A Simpson P Macpherson G Patton JT Hamilton DF

Aims. The primary aim of the study was to compare the knee-specific functional outcome of robotic unicompartmental knee arthroplasty (rUKA) with manual total knee arthroplasty (mTKA) for the management of isolated medial compartment osteoarthritis. Secondary aims were to compare length of hospital stay, general health improvement, and satisfaction between rUKA and mTKA. Methods. A powered (1:3 ratio) cohort study was performed. A total of 30 patients undergoing rUKA were propensity score matched to 90 patients undergoing mTKA for isolated medial compartment arthritis. Patients were matched for age, sex, body mass index (BMI), and preoperative function. The Oxford Knee Score (OKS) and EuroQol five-dimension questionnaire (EQ-5D) were collected preoperatively and six months postoperatively. The Forgotten Joint Score (FJS) and patient satisfaction were collected six months postoperatively. Length of hospital stay was also recorded. Results. There were no significant differences in the preoperative demographics (p ⩾ 0.150) or function (p ⩾ 0.230) between the groups. The six-month OKS was significantly greater in the rUKA group when compared with the mTKA group (difference 7.7, p < 0.001). There was also a greater six-month postoperative EQ-5D (difference 0.148, p = 0.002) and FJS (difference 24.2, p < 0.001) for the rUKA when compared to the mTKA. No patient was dissatisfied in the rUKA group and five (6%) were dissatisfied in the mTKA, but this was not significant (p = 0.210). Length of stay was significantly (p < 0.001) shorter in the rUKA group (median two days, interquartile range (IQR) 1 to 3) compared to the mTKA (median four days, IQR 3 to 5). Conclusion. Patients with isolated medial compartment arthritis had a greater knee-specific functional outcome and generic health with a shorter length of hospital stay after rUKA when compared to mTKA. Cite this article: Bone Joint Res 2019;9(1):15–22


The Bone & Joint Journal
Vol. 101-B, Issue 3 | Pages 340 - 347
1 Mar 2019
Elkassabany NM Cai LF Badiola I Kase B Liu J Hughes C Israelite CL Nelson CL

Aims. Adductor canal block (ACB) has emerged as an alternative to femoral nerve block (FNB) for analgesia after total knee arthroplasty (TKA). The optimal duration of maintenance of the ACB is still questionable. The purpose of this study was to compare the analgesic benefits and physiotherapy (PT) outcomes of single-shot ACB to two different regimens of infusion of the continuous ACB, 24-hour and 48-hour infusion. Patients and Methods. This was a prospective, randomized, unblinded study. A total of 159 American Society of Anesthesiologists (ASA) physical status I to III patients scheduled for primary TKA were randomized to one of three study groups. Three patients did not complete the study, leaving 156 patients for final analysis. Group A (n = 53) was the single-shot group (16 female patients and 37 male patients with a mean age of 63.9 years (. sd. 9.6)), group B (n = 51) was the 24-hour infusion group (22 female patients and 29 male patients with a mean age of 66.5 years (. sd. 8.5)), and group C (n = 52) was the 48-hour infusion group (18 female patients and 34 male patients with a mean age of 62.2 years (. sd. 8.7)). Pain scores, opioid requirements, PT test results, and patient-reported outcome instruments were compared between the three groups. Results. The proportion of patients reporting severe pain, defined as a pain score of between 7 and 10, on postoperative day number 2 (POD 2) were 21% for the single-shot group, 14% for the 24-hour block group, and 12% for the 48-hour block group (p = 0.05). Cumulative opioid requirements after 48 hours were similar between the groups. Functional outcomes were similar in all three groups in POD 1 and POD 2. Conclusion. There was no clear benefit of the 24-hour or 48-hour infusions over the single-shot ACB for the primary endpoint of the study. Otherwise, there were marginal benefits for keeping the indwelling catheter for 48 hours in terms of reducing the number of patients with moderate pain and improving the quality of pain management. However, all three groups had similar opioid usage, length of hospital stay, and functional outcomes. Further studies with larger sample sizes are needed to confirm these findings. Cite this article: Bone Joint J 2019;101-B:340–347


The Bone & Joint Journal
Vol. 96-B, Issue 7 | Pages 907 - 913
1 Jul 2014
Dossett HG Estrada NA Swartz GJ LeFevre GW Kwasman BG

We have previously reported the short-term radiological results of a randomised controlled trial comparing kinematically aligned total knee replacement (TKR) and mechanically aligned TKR, along with early pain and function scores. In this study we report the two-year clinical results from this trial. A total of 88 patients (88 knees) were randomly allocated to undergo either kinematically aligned TKR using patient-specific guides, or mechanically aligned TKR using conventional instruments. They were analysed on an intention-to-treat basis. The patients and the clinical evaluator were blinded to the method of alignment.

At a minimum of two years, all outcomes were better for the kinematically aligned group, as determined by the mean Oxford knee score (40 (15 to 48) versus 33 (13 to 48); p = 0.005), the mean Western Ontario McMaster Universities Arthritis index (WOMAC) (15 (0 to 63) versus 26 (0 to 73); p = 0.005), mean combined Knee Society score (160 (93 to 200) versus 137 (64 to 200); p= 0.005) and mean flexion of 121° (100 to 150) versus 113° (80 to 130) (p = 0.002). The odds ratio of having a pain-free knee at two years with the kinematically aligned technique (Oxford and WOMAC pain scores) was 3.2 (p = 0.020) and 4.9 (p = 0.001), respectively, compared with the mechanically aligned technique. Patients in the kinematically aligned group walked a mean of 50 feet further in hospital prior to discharge compared with the mechanically aligned group (p = 0.044).

In this study, the use of a kinematic alignment technique performed with patient-specific guides provided better pain relief and restored better function and range of movement than the mechanical alignment technique performed with conventional instruments.

Cite this article: Bone Joint J 2014;96-B:907–13.