Aims

The purpose of this study was to assess mid-term survivorship following primary total knee arthroplasty (TKA) with Optetrak Logic components and identify the most common revision indications at a single institution.

Aims. The aim is to assess the cost-effectiveness of patellofemoral arthroplasty (PFA) in comparison with total knee arthroplasty (TKA) for the treatment of isolated patellofemoral osteoarthritis (OA) based on prospectively collected data on health outcomes and resource use from a blinded, randomized, clinical trial. Methods. A total of 100 patients with isolated patellofemoral osteoarthritis were randomized to receive either PFA or TKA by experienced knee surgeons trained in using both implants. Patients completed patient-reported outcomes including EuroQol five-dimension questionnaire (EQ-5D) and 6-Item Short-Form Health Survey questionnaire (SF-6D) before the procedure. The scores were completed again after six weeks, three, six, and nine months, and again after one- and two-year post-surgery and yearly henceforth. Time-weighted outcome measures were constructed. Cost data were obtained from clinical registrations and patient-reported questionnaires. Incremental gain in health outcomes (quality-adjusted life-years (QALYs)) and incremental costs were compared for the two groups of patients. Net monetary benefit was calculated assuming a threshold value of €10,000, €35,000, and €50,000 per QALY and used to test the statistical uncertainty and central assumptions about outcomes and costs. Results. The PFA group had an incremental 12 month EQ-5D gain of 0.056 (95% confidence interval (CI) 0.01 to 0.10) and an incremental 12 month cost of minus €328 (95% CI 836 to 180). PFA therefore dominates TKA by providing better and cheaper outcomes than TKA. The net monetary benefit of PFA was €887 (95% CI 324 to 1450) with the €10,000 threshold, and it was consistently positive when different measures of outcomes and different cost assumptions were used. Conclusion. This study provides robust evidence that PFA from a one-year hospital management perspective is cheaper and provides better outcomes than TKA when applied to patients with isolated patellofemoral osteoarthritis and performed by experienced knee surgeons. Cite this article: Bone Joint J 2020;102-B(4):449–457

Aims

The diagnosis of periprosthetic joint infection (PJI) can be challenging as the symptoms are similar to other conditions, and the markers used for diagnosis have limited sensitivity and specificity. Recent research has suggested using blood cell ratios, such as platelet-to-volume ratio (PVR) and platelet-to-lymphocyte ratio (PLR), to improve diagnostic accuracy. The aim of the study was to further validate the effectiveness of PVR and PLR in diagnosing PJI.

Aims

The goal was to evaluate tibiofemoral knee joint kinematics during stair descent, by simulating the full stair descent motion in vitro. The knee joint kinematics were evaluated for two types of knee implants: bi-cruciate retaining and bi-cruciate stabilized. It was hypothesized that the bi-cruciate retaining implant better approximates native kinematics.

Aims

The purpose of this study was to compare reoperation and revision rates of double plating (DP), single plating using a lateral locking plate (SP), or distal femoral arthroplasty (DFA) for the treatment of periprosthetic distal femur fractures (PDFFs).

Aims. The primary aim of this study was to assess whether the postoperative Oxford Knee Score (OKS) demonstrated a ceiling effect at one and/or two years after total knee arthroplasty (TKA). The secondary aim was to identify preoperative independent predictors for patients that achieved a ceiling score after TKA. Methods. A retrospective cohort of 5,857 patients undergoing a primary TKA were identified from an established arthroplasty database. Patient demographics, body mass index (BMI), OKS, and EuroQoL five-dimension (EQ-5D) general health scores were collected preoperatively and at one and two years postoperatively. Logistic regression analysis was used to identify independent preoperative predictors of patients achieving postoperative ceiling scores. Receiver operating characteristic curve was used to identify a preoperative OKS that predicted a postoperative ceiling score. Results. The ceiling effect was 4.6% (n = 272) at one year which increased significantly (odds ratio (OR) 40.3, 95% confidence interval (CI) 30.4 to 53.3; p < 0.001) to 6.2% (n = 363) at two years, when defined as those with a maximal score of 48 points. However, when the ceiling effect was defined as an OKS of 44 points or more, this increased to 26.3% (n = 1,540) at one year and further to 29.8% (n = 1,748) at two years (OR 21.6, 95% CI 18.7 to 25.1; p < 0.001). A preoperative OKS of 23 or more and 22 or more were predictive of achieving a postoperative ceiling OKS at one and two years when defined as a maximal score or a score of 44 or more, respectively. Conclusion. The postoperative OKS demonstrated a small ceiling effect when defined by a maximal score, but when defined by a postoperative OKS of 44 or more the ceiling effect was moderate and failed to meet standards. The preoperative OKS was an independent predictor of achieving a ceiling score. Cite this article: Bone Joint J 2020;102-B(11):1519–1526

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

Aims. To evaluate the influence of discharge timing on 30-day complications following total knee arthroplasty (TKA). Patients and Methods. We identified patients aged 18 years or older who underwent TKA between 2005 and 2016 from the American College of Surgeons’ National Surgical Quality Improvement Program (NSQIP) database. We propensity score-matched length-of-stay (LOS) groups using all relevant covariables. We used multivariable regression to determine if the rate of complications and re-admissions differed depending on LOS. Results. Our matched cohort consisted of 76 246 TKA patients (mean age 67 years . (sd. 9)). Patients whose LOS was zero and four days had an increased risk of major complications by an odds ratio (OR) of 1.8 (95% confidence interval (CI) 1.0 to 3.2) and 1.5 (95% CI 1.2 to 1.7), respectively, compared with patients whose LOS was two days. Patients whose LOS was zero, three, and four days had an increased risk of minor complications (OR 1.8 (95% CI 1.3 to 2.7), 1.2 (95% CI 1.0 to 1.4), and 1.6 (95% CI 1.4 to 1.9), respectively), compared with patients whose LOS was two days. In addition, a LOS of three days increased the risk of re-admission by an OR of 1.2 (95% CI 1.0 to 1.3), and a LOS of four days increased the risk of re-admission by an OR of 1.5 (95% CI 1.3 to 1.6), compared with a LOS of two days. Conclusion. Patients discharged on days one to two postoperatively following TKA appear to have reduced major and minor complications compared with discharge on the day of surgery, or on days three to four. Prospective clinical data are required to confirm these findings. Cite this article: Bone Joint J 2019;101-B(7 Supple C):70–76

Aims. The introduction of a novel design of total knee arthroplasty (TKA) must achieve outcomes at least as good as existing designs. A novel design of TKA with a reducing radius of the femoral component and a modified cam-post articulation has been released and requires assessment of the fixation to bone. Radiostereometric analysis (RSA) of the components within the first two postoperative years has been shown to be predictive of medium- to long-term fixation. The aim of this study was to assess the stability of the tibial component of this system during this period of time using RSA. Patients and Methods. A cohort of 30 patients underwent primary, cemented TKA using the novel posterior stabilized fixed-bearing (ATTUNE) design. There was an even distribution of men and women (15:15). The mean age of the patients was 64 years (sd 8) at the time of surgery; their mean body mass index (BMI) was 35.4 kg/m2 (sd 7.9). RSA was used to assess the stability of the tibial component at 6, 12, and 24 months compared with a six-week baseline examination. Patient-reported outcome measures were also assessed. Results. The mean maximum total point motion (MTPM) of the tibial component between 12 and 24 months postoperatively was 0.08 mm (sd 0.08), which is well below the published threshold of 0.2 mm (p < 0.001). Patient-reported outcome measures consistently improved. Conclusion. The tibial component of this novel design of TKA showed stability between assessment 12 and 24 months postoperatively, suggesting an acceptably low risk of medium- to long-term failure due to aseptic loosening

Aims. Knee osteonecrosis in advanced stages may lead to joint degeneration. Total knee arthroplasty (TKA) for osteonecrosis has traditionally been associated with suboptimal results. We analyzed outcomes of contemporary TKAs for osteonecrosis, with particular emphasis on: survivorship free from aseptic loosening, any revision, and any reoperation plus the clinical outcomes, complications, and radiological results. Patients and Methods. In total, 156 patients undergoing 167 primary TKAs performed for osteonecrosis between 2004 and 2014 at a single institution were reviewed. The mean age at index TKA was 61 years (14 to 93) and the mean body mass index (BMI) was 30 kg/m. 2. (18 to 51) The mean follow-up was six years (2 to 12). A total of 110 TKAs (66%) were performed for primary osteonecrosis and 57 TKAs (34%) for secondary osteonecrosis. Overall, 15 TKAs (9%) had tibial stems, while 12 TKAs (7%) had femoral stems. Posterior-stabilized designs were used in 147 TKAs (88%) of TKAs. Bivariate Cox regression analysis was conducted to identify risk factors for revision and reoperation. Results. Survivorship free from aseptic loosening, any revision, and any reoperation at ten years was 97% (95% confidence interval (CI) 93 to 100), 93% (95% CI 85 to 100), and 82% (95% CI 69 to 93), respectively. No factors, including age, sex, BMI, primary versus secondary osteonecrosis, stem utilization, and constraint, were identified as risk factors for reoperation. Four TKAs (2%) underwent revision, most commonly for tibial aseptic loosening (n = 2). Excluding revisions and reoperations, there was a total of 11 complications (7%), with the most common being a manipulation under anaesthesia (six TKAs, 4%). Mean Knee Society Scores (Knee component) significantly improved from 57 (32 to 87) preoperatively to 91 (49 to 100) postoperatively (p < 0.001). No unrevised TKAs had complete radiolucent lines or radiological evidence of loosening. Conclusion. Contemporary cemented TKAs with selective stem utilization for osteonecrosis resulted in durable survivorship, a low complication rate, and reliable improvement in clinical outcomes. Cite this article: Bone Joint J 2019;101-B:1356–1361

Aims

We have previously reported the mid-term outcomes of revision total knee arthroplasty (TKA) for flexion instability. At a mean of four years, there were no re-revisions for instability. The aim of this study was to report the implant survivorship and clinical and radiological outcomes of the same cohort of of patients at a mean follow-up of ten years.

Aims. The outcomes of total knee arthroplasty (TKA) depend on many factors. The impact of implant design on patient-reported outcomes is unknown. Our goal was to evaluate the patient-reported outcomes and satisfaction after primary TKA in patients with osteoarthritis undergoing primary TKA using five different brands of posterior-stabilized implant. Patients and Methods. Using our institutional registry, we identified 4135 patients who underwent TKA using one of the five most common brands of implant. These included Biomet Vanguard (Zimmer Biomet, Warsaw, Indiana) in 211 patients, DePuy/Johnson & Johnson Sigma (DePuy Synthes, Raynham, Massachusetts) in 222, Exactech Optetrak Logic (Exactech, Gainesville, Florida) in 1508, Smith & Nephew Genesis II (Smith & Nephew, London, United Kingdom) in 1415, and Zimmer NexGen (Zimmer Biomet) in 779 patients. Patients were evaluated preoperatively using the Knee Injury and Osteoarthritis Outcome Score (KOOS), Lower Extremity Activity Scale (LEAS), and 12-Item Short-Form Health Survey questionnaire (SF-12). Demographics including age, body mass index, Charlson Comorbidity Index, American Society of Anethesiologists status, sex, and smoking status were collected. Postoperatively, two-year KOOS, LEAS, SF-12, and satisfaction scores were compared between groups. Results. Outcomes were available for 4069 patients (98%) at two years postoperatively. In multiple regression analysis, which separately compared each implant group with the aggregate of all others, there were no clinically significant differences in the change of KOOS score from baseline to two-year follow-up between any of the groups. More than 80% of patients in each group were satisfied at this time in all domains. In a multivariate regression model, patients in the NexGen group were the most likely to be satisfied (odds ratio (OR) 1.63; p = 0.006) and Optetrak Logic patients were the least likely to be satisfied (OR 0.60; p < 0.001). Conclusion. TKA provides improvement in function and satisfaction regardless of the type of implant. We could not demonstrate superiority of one design above others across these groups of implants, and any price premium for one above the other systems may not be justified. Healthcare administrators may find these similarities in outcomes helpful when negotiating purchasing contracts. Cite this article: Bone Joint J 2019;101-B(7 Supple C):48–54

Aims. Responsiveness to clinically important change is a key feature of any outcome measure. Throughout Europe, health-related quality of life following total knee arthroplasty (TKA) is routinely measured with EuroQol five-dimension (EQ-5D) questionnaires. The Patient-Reported Outcomes Measurement Information System 10-Question Short-Form (PROMIS-10 Global Health) score is a new general heath outcome tool which is thought to offer greater responsiveness. Our aim was to compare these two tools. Patients and Methods. We accessed data from a prospective multicentre cohort study in the United Kingdom, which evaluated outcomes following TKA. The median age of the 721 patients was 69.0 years (interquartile range, 63.3 to 74.6). There was an even division of sex, and approximately half were educated to secondary school level. The preoperative EQ-5D, PROMIS-10, and Oxford Knee Scores (OKS) were available and at three, six, and 12 months postoperatively. Internal responsiveness was assessed by standardized response mean (SRM) and effect size (Cohen’s d). External responsiveness was assessed by correlating change scores of the EQ-5D and PROMIS-10, with the minimal clinically important difference (MCID) of the OKS. Receiver operating characteristic (ROC) curves were used to assess the ability of change scores to discriminate between improved and non-improved patients. Results. All measures showed significant changes between the preoperative score and the various postoperative times (p < 0.001). Most improvement occurred during the first three months, with small but significant changes between three and six months, and no further change between six and 12 months postoperatively. SRM scores for EQ-5D, PROMIS-10, and OKS were large (> 0.8). ROC curves showed that both EQ-5D and PROMIS-10 were able to discriminate between patients who achieved the OKS MCID and those who did not (area under the curve (AUC) of 0.7 to 0.82). Conclusion. The PROMIS-10 physical health tool showed greater responsiveness to change than the EQ-5D, most probably due to the additional questions on physical health parameters that are more susceptible to modification following TKA. The EQ-5D was, however, shown to be sensitive to clinically meaningful change following TKA, and provides the additional ability to calculate health economic utility scores. It is likely, therefore, that EQ-5D will continue to be the global health metric of choice in the United Kingdom. Cite this article: Bone Joint J 2019;101-B:832–837

Aims. Fungal prosthetic joint infections (PJIs) are rare and account for about 1% of total PJIs. Our aim was to present clinical and microbiological results in treating these patients with a two-stage approach and antifungal spacers. Patients and Methods. We retrospectively reviewed our institutional database and identified 26 patients with positive fungal cultures and positive Musculoskeletal Infection Society (MSIS) criteria for PJI who were treated between 2009 and 2017. We identified 18 patients with total hip arthroplasty (THA) and eight patients with total knee arthroplasty (TKA). The surgical and antifungal treatment, clinical and demographic patient data, complications, relapses, and survival were recorded and analyzed. Results. The median follow-up was 33 months. The success rate was 38.5% (10/26). Fluconazole resistance was found in 15%. Bacterial co-infection was common in 44% of patients for THA and 66% of patients with TKA. Mortality, reoperations, and treatment failure were common complications. Conclusion. Treatment with a two-stage exchange is a possible option for treatment, although fungal infections have a high failure rate. Therapeutic factors for treatment success remain unclear. Cite this article: Bone Joint J 2019;101-B:589–595

Aims. As the population ages, there is projected to be an increase in the level of demand for total knee arthroplasty (TKA) in octogenarians. We aimed to explore whether those aged ≥ 80 years achieved similar improvements in physical function to younger patients while also comparing the rates of length of stay (LOS), discharge to rehabilitation, postoperative complications, and mortality following TKA in older and younger patients. Patients and Methods. Patients from one institution who underwent primary elective TKA between 1 January 2006 and 31 December 2014 were dichotomized into those ≥ 80 years old (n = 359) and those < 80 years old (n = 2479) for comparison. Multivariable regression was used to compare the physical status component of the 12-Item Short-Form Health Survey (SF-12), LOS, discharge to rehabilitation, complications, and mortality between the two groups. Results. Both age groups demonstrated a clinically meaningful improvement in their self-reported physical health relative to their baseline with no clinically relevant difference noted between them. Being ≥ 80 years old was associated with a 0.58-day increase in LOS and older patients were more likely to be discharged to rehabilitation (odds ratio (OR) 3.06, p < 0.001). Medical complications and mortality were higher in elderly patients (OR 1.92 for complications, p < 0.001; hazard ratio 3.40 for death, p < 0.001). There was no statistically significant association between age group and experiencing a postoperative surgical or wound-related complication. Conclusion. Those aged over 80 years achieved a statistically significant lower median SF-12 physical score than the younger group, after adjusting for the preoperative score, but this difference of 4.46 was not considered to be clinically meaningful. However, clinicians should be aware that the elderly are at a higher risk of experiencing longer hospital stays, postoperative medical complications, and mortality. Cite this article: Bone Joint J 2018;100-B:1463–70

Aims. The aim of this study was to determine whether closed suction drain (CSD) use influences recovery of quadriceps strength and to examine the effects of drain use on secondary outcomes: quadriceps activation, intra-articular effusion, bioelectrical measure of swelling, range of movement (ROM), pain, and wound healing complications. Patients and Methods. A total of 29 patients undergoing simultaneous bilateral total knee arthroplasty (TKA) were enrolled in a prospective, randomized blinded study. Patients were randomized to receive a CSD in one limb while the contralateral limb had the use of a subcutaneous drain (SCDRN) without the use of suction (‘sham drain’). Isometric quadriceps strength was collected as the primary outcome. Secondary outcomes consisted of quadriceps activation, intra-articular effusion measured via ultrasound, lower limb swelling measured with bioelectrical impendence and limb girth, knee ROM, and pain. Outcomes were assessed preoperatively and postoperatively at day two, two and six weeks, and three months. Differences between limbs were determined using paired Student’s t-tests or Wilcoxon’s signed-rank tests. Results. No significant differences were identified between limbs prior to surgery for the primary or secondary outcomes. No significant differences in quadriceps strength were seen between CSD and SCDRN limbs at postoperative day two (p = 0.09), two weeks (primary endpoint) (p = 0.7), six weeks (p = 0.3), or three months (p = 0.5). The secondary outcome of knee extension ROM was significantly greater in the CSD limb compared with the SCDRN (p = 0.01) at two weeks following surgery, but this difference was absent at all other intervals. Secondary outcomes of quadriceps activation, intra-articular effusion, lower limb swelling, and pain were not found to differ significantly at any timepoint following surgery. Conclusion. The use of CSD during TKA did not influence quadriceps strength, quadriceps activation, intra-articular effusion, lower limb swelling, ROM, or pain. These results have limited drain use by the authors in primary uncomplicated TKA. Cite this article: Bone Joint J 2019;101-B (7 Supple C):84–90

Aims

To investigate the impact of consecutive perioperative care transitions on in-hospital recovery of patients who had primary total knee arthroplasty (TKA) over an 11-year period.

Aims. The aims of this study were to characterize antibiotic choices for perioperative total knee arthroplasty (TKA) and total hip arthroplasty (THA) prophylaxis, assess antibiotic allergy testing efficacy, and determine rates of prosthetic joint infection (PJI) based on perioperative antibiotic regimen. Patients and Methods. We evaluated all patients undergoing primary TKA or THA at a single academic institution between January 2004 and May 2017, yielding 29 695 arthroplasties (22 705 patients), with 3411 arthroplasties in 2576 patients (11.5%) having undergone preoperative allergy testing. A series of institutional databases were combined to identify allergy consultation outcomes, perioperative antibiotic regimen, and infection-free survivorship until final follow-up. Results. Among 2576 allergy-tested patients, 2493 patients (97%) were cleared to use cephalosporins. For the entire cohort, 28 174 arthroplasties (94.9%) received cefazolin and 1521 (5.1%) received non-cefazolin antibiotics. Infection-free survivorship was significantly higher among arthroplasties receiving cefazolin compared with non-cefazolin antibiotics, with 0.06% higher survival free of infection at one month, 0.56% at two months, 0.61% at one year, and 1.19% at ten years (p < 0.001). Overall, the risk of PJI was 32% lower in patients treated with cefazolin after adjusting for the American Society of Anesthesiologists (ASA) classification, joint arthroplasty (TKA or THA), and body mass index (BMI; p < 0.001). The number needed to treat with cefazolin to prevent one PJI was 164 patients at one year and 84 patients at ten years. Therefore, potentially 6098 PJIs could be prevented by one year and 11 905 by ten years in a cohort of 1 000 000 primary TKA and THA patients. Conclusion. PJI rates are significantly higher when non-cefazolin antibiotics are used for perioperative TKA and THA prophylaxis, highlighting the positive impact of preoperative antibiotic allergy testing to increase cefazolin usage. Given the low rate of true penicillin allergy positivity, and the readily modifiable risk factor that antibiotic choice provides, we recommend perioperative testing and clearance for all patients presenting with penicillin and cephalosporin allergies. Cite this article: Bone Joint J 2019;101-B(6 Supple B):9–15

Aims. The primary aim of this paper was to outline the processes involved in building the Partners Arthroplasty Registry (PAR), established in April 2016 to capture baseline and outcome data for patients undergoing arthroplasty in a regional healthcare system. A secondary aim was to determine the quality of PAR’s data. A tertiary aim was to report preliminary findings from the registry and contributions to quality improvement initiatives and research up to March 2019. Methods. Structured Query Language was used to obtain data relating to patients who underwent total hip or knee arthroplasty (THA and TKA) from the hospital network’s electronic medical record (EMR) system to be included in the PAR. Data were stored in a secure database and visualized in dashboards. Quality assurance of PAR data was performed by review of the medical records. Capture rate was determined by comparing two months of PAR data with operating room schedules. Linear and binary logistic regression models were constructed to determine if length of stay (LOS), discharge to a care home, and readmission rates improved between 2016 and 2019. Results. The PAR captured 16,163 THAs and TKAs between April 2016 and March 2019, performed in seven hospitals by 110 surgeons. Manual comparison to operating schedules showed a 100% capture rate. Review of the records was performed for 2,603 random operations; 2,298 (88.3%) had complete and accurate data. The PAR provided the data for three abstracts presented at international conferences and has led to preoperative mental health treatment as a quality improvement initiative in the participating institutions. For primary THA and TKA surgeries, the LOS decreased significantly (p < 0.001) and the rate of home discharge increased significantly (p < 0.001) between 2016 and 2019. Readmission rates did not correlated with the date of surgery (p = 0.953). Conclusion. The PAR has high rates of coverage (the number of patients treated within the Partners healthcare network) and data completion and can be used for both research purposes and quality improvement. The same method of creating a registry that was used in the PAR can be applied to hospitals using similar EMR systems. Cite this article: Bone Joint J 2020;102-B(7 Supple B):90–98

Aims

Fungal periprosthetic joint infections (PJIs) are rare, but their diagnosis and treatment are highly challenging. The purpose of this study was to investigate the clinical outcomes of patients with fungal PJIs treated with two-stage exchange knee arthroplasty combined with prolonged antifungal therapy.