When does patient function "Plateau" after total joint arthroplasty? A cohort study.

PURPOSE: With over 100,000 procedures completed per year, hip and knee arthroplasty are two of the most common surgical procedures performed in Canada. There has been literature indicating that patient reported outcome measures (PROM) will start to plateau between six and 12 months. The purpose of this paper was to analyze the trajectory of PROMs following total hip and knee arthroplasty (THA and TKA), as well as assess the impact of any potential confounders on this trajectory. The central research question was: At what point do PROMS plateau among patients that undergo elective THA and TKA? METHODS: This study was a retrospective analysis of data from a prospective database. Patients were eligible if they had undergone an elective, primary THA/TKA with Oxford Scores recorded pre-operatively, and at least at two of the following four time points: six weeks, six months, one year, and two years. RESULTS: Mean pre-operative Oxford scores were 18.0 (7.8) for THA, and 20.1 (7.5) for TKA. For both THA and TKA, there were statistically significant interval improvements in Oxford scores from six weeks [THA: 33.8 (7.9)/TKA: 28.7 (7.8)] to six months [THA: 40.2 (7.3)/TKA: 35.9 (8.3)], and from six months to one year [THA: 41.0 (7.3)/TKA: 37.3 (8.4)], but not from one to two years [THA: 40.0 (8.5)/TKA: 36.4 (9.6)]. CONCLUSIONS: Patients undergoing either primary THA or TKA can expect clinically meaningful improvements in the first six months after surgery. Beyond this time point, there is a plateau in PROMs. These findings are important for both setting patient expectations in pre-operative discussions, and allowing surgeons to have a realistic understanding of their patients' expected post-operative course.

Management of Greater Trochanteric Pain Syndrome After Total Hip Arthroplasty: Practice Patterns and Surgeon Attitudes.

INTRODUCTION: Greater trochanteric pain syndrome (GTPS) or trochanteric bursitis is described as pain on the lateral side of the hip that does not involve the hip joint and can be elicited clinically by palpation over the greater trochanter. To date, there remains no consensus on clinical guidelines for either diagnosis or management of GTPS. METHODS: To understand the practice patterns, beliefs, and attitudes relating to the management of GTPS after total hip arthroplasty, a survey was developed and completed by Canadian arthroplasty surgeons. The final survey consisted of 23 questions divided into three sections: 1) screening questions; 2) demographic information; and 3) practice patterns, attitudes, and beliefs. RESULTS: Most surgeons use physical examination alone for diagnosis. A detailed analysis indicates that surgeons primarily treat GTPS with oral anti-inflammatories (57.1%), structured physiotherapy (52.4%), and steroid injections (45.2%). Management options are typically nonsurgical and comprise a combination of either unstructured or targeted physiotherapy, corticosteroid injections, or platelet-rich plasma. DISCUSSION: There remains an absence of clinical consensus for the diagnosis and management of GTPS after total hip arthroplasty. Physical examination is most often relied on, regardless of the availability of imaging aids. While common treatments of GTPS were identified, up to one-third of patients fail initial therapy.

Risk factors for recurrence of periprosthetic joint infection following operative management: a cohort study with average 5-year follow-up.

Background: Periprosthetic joint infections (PJIs) remain challenging to eradicate even after surgical management, which in most cases involves either debridement, antibiotics and implant retention (DAIR) or single- or two-staged revision. The purpose of this study is to determine predictors of PJI recurrence after operative management for PJI, and to determine differences in recurrence-free survival between DAIR and staged revision. Methods: This is a retrospective analysis of prospectively collected data of revision hip and knee arthroplasty surgeries due to PJI between 2011 and 2018 at an academic hospital. Any patient undergoing revision surgery for PJI was included except if the index surgery information was unknown. The primary outcome was confirmed PJI recurrence. Multivariable logistic regression analysis was utilized to determine the relationship between the predictor variables and outcome variable. Log rank testing was used to compare recurrence-free survival between DAIR and staged revision. Results: A total of 89 patients (91 joints) underwent revision surgery due to PJI. Younger age and presence of a sinus tract were statistically significant for risk of PJI recurrence. A multivariable logistic regression model including both variables was significant for predicting recurrence of PJI (χ2=10.2, P=0.006). Survival was not significantly different between patients who underwent DAIR versus a staged revision. Conclusions: Younger patients and those with a chronic sinus tract are at significantly higher risk of recurrent PJI. This study also demonstrated that PJI can be successfully managed in the majority of cases with DAIR or staged revision.

Unicompartmental Knee Arthroplasty: Survivorship and Risk Factors for Revision: A Population-Based Cohort Study with Minimum 10-Year Follow-up.

BACKGROUND: Operative management for end-stage knee osteoarthritis (OA) primarily consists of arthroplasty. Total knee arthroplasty (TKA) is the so-called gold standard for multicompartmental OA. In selected patients, specifically those with unicompartmental OA and no definite contraindications, realignment osteotomies and unicompartmental knee arthroplasty (UKA) are viable options. UKA offers several advantages over TKA, including preservation of both cruciate ligaments, faster recovery, and less osseous resection. The purpose of this study was to determine the survivorship of UKAs and risk factors for all-cause revision surgery in patients with a minimum follow-up of 10 years in a large population-based database. METHODS: We performed a population-based cohort study using linked administrative databases in Ontario, Canada. We identified all UKAs performed from January 2002 through December 2006. All patients had a minimum 10-year follow-up. Demographic data and outcomes were summarized using descriptive statistics. We used a Cox proportional hazards model with the Fine and Gray method accounting for competing risks such as death to analyze the effect of surgical and patient factors on the risk of revision of UKA. RESULTS: A total of 4,385 patients were identified as having undergone primary UKA from 2002 through 2006 in Ontario. Of these patients, 779 underwent revision surgery, for a cumulative risk for all-cause revision of 16.5% at 10 years (95% confidence interval [CI]: 15.4% to 17.7%). Mechanical loosening was the reason for 83.4% of all revisions. Male sex, diabetes, an age younger than 50 years, and cementless implants were significant risk factors for revision surgery. Residence in a rural or urban setting, income quintile, discharge destination, and type of OA were not associated with the risk of revision. Survivorship at 1, 5, 10, and 15 years was 97.2%, 90.5%, 83.5%, and 81.9%, respectively. CONCLUSIONS: This study demonstrated a >80% long-term survivorship for UKA based on a large administrative database sample and identified important risk factors for failure including male sex, younger age, diabetes, and cementless fixation. This study found rates of survivorship similar to those previously reported in the literature, while identifying key risk factors for failure. Patient selection has always been identified as a key factor in ensuring successful UKA, and the risk factors identified in this study may help guide decision-making for surgeons and patients dealing with unicompartmental knee OA. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The Changing Characteristics of Arthroplasty Patients: A Retrospective Cohort Study.

BACKGROUND: Total joint arthroplasty (TJA) is among the most common operations performed worldwide, with global volumes on the rise. It is important to understand if the characteristics of this patient population are changing over time for resource allocation and surgical planning. The purpose of this study is to examine how this patient population has changed between 2003 and 2017. METHODS: A retrospective review of a prospective TJA database was conducted. Age, gender, body mass index, comorbidities, American Society of Anesthesiologists class, responsible diagnoses, and comorbidities were compared over 5-year intervals between 2003 and 2017. All patients undergoing primary, elective TJA were included. RESULTS: Overall, 17,138 TJAs were included. Mean body mass index increased over the study period for total hip arthroplasty (THA; 29.4-30.4 kg/m2, P < .0001) and total knee arthroplasty (TKA; 32.0-3.1 kg/m2, P < .0001) patients. THA patients were significantly younger in more recent years (68.0-66.8 years old, P = .0026); this trend was not observed among TKA patients. Over the study period, a significantly higher proportion of patients were American Society of Anesthesiologists class III/IV for THA (50.5%-72.3%) and TKA (57.5%-80.7%) (P < .00001). Prevalence of common comorbidities did not change significantly. CONCLUSION: The key findings of this retrospective analysis of a large prospective database are that patients undergoing TJA are becoming younger and more obese. It is unclear whether patients are becoming more medically complex. These trends paint a concerning picture of a population that is increasingly complex, and may require a greater allocation of resources in the future. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Randomized Controlled Trial of Sensor-Guided Knee Balancing Compared to Standard Balancing Technique in Total Knee Arthroplasty.

BACKGROUND: Despite advances in total knee arthroplasty (TKA) technology, up to 1 in 5 patients remain dissatisfied. This study sought to evaluate if sensor-guided knee balancing improves postoperative clinical outcomes and patient satisfaction compared to a conventional gap balancing technique. METHODS: We undertook a prospective double-blind randomized controlled trial of patients presenting for elective primary TKA to determine a difference in TKA soft tissue balance between a standard gap balancing (tensiometer) approach compared to augmenting the balance using a sensor-guided device. The sensor-guided experimental group had adjustments made to achieve a balanced knee to within 15 pounds of intercompartmental pressure difference. Secondary outcomes included differences in clinical outcome scores at 6 months and 1 year postoperative, including the Oxford Knee Score and Knee Society Score and patient satisfaction. RESULTS: The sample comprised of 152 patients, 76 controls and 76 experimental sensor-guided cases. Within the control group, 36% (27/76) of knees were unbalanced based on an average coronal plane intercompartmental difference >15 pounds, compared to only 5.3% (4/76) within the experimental group (P < .0001). There were no significant differences in 1-year postoperative flexion, Knee Society Score, or Oxford scores. Overall, TKA patient satisfaction at 1 year was comparable, with 81% of controls and experimental cases reporting they were very satisfied (P = .992). CONCLUSION: Despite the use of the sensor-guided knee balancer device to provide additional quantitative feedback in the evaluation of the soft tissue envelope during TKA, we were unable to demonstrate improved clinical outcomes or patient satisfaction compared to our conventional gap balancing technique.

Nuisance Symptoms in Total Joint Arthroplasty: Prevalence and Impact on Patient Satisfaction.

BACKGROUND: While hip and knee total joint arthroplasty (TJA) patients experience marked improvement in pain relief and function, many patients experience nuisance symptoms, which may cause discomfort and dissatisfaction. METHODS: A prospective survey study to determine type and prevalence of hip/knee TJA nuisance symptoms and impact on patient satisfaction at 1 year postoperative was conducted. The survey determined occurrence of common nuisance symptoms (eg, localized pain, swelling, instability, stiffness) and impact on overall satisfaction rated on a 10-point visual analog scale (VAS). Survey responses were analyzed using descriptive statistics. RESULTS: The sample comprised 545 TJA patients who completed the survey: 335 knees (61%) and 210 hips (39%). Among knees, the most commonly reported nuisance symptoms and associated impact on satisfaction included difficulty kneeling (78.2%; VAS, 4.3; SD, 3.3), limited ability to run/jump (71.6%; VAS, 3.3; SD, 3.3), and numbness around incision (46.3%; VAS, 3.8; SD, 3.3). Overall, 94% of knee patients experienced at least 1 nuisance symptom at 1 year, reporting mean satisfaction of 9/10 (SD, 1.7). Among hips, the most commonly reported nuisance symptoms and associated impact on satisfaction were limited ability to run/jump (68.6%; VAS, 3.4; SD, 3.4), thigh muscle pain (44.8%; VAS, 3; SD, 2.7), and limp when walking (37.6%; VAS, 4.1; SD, 3.2). Overall, 88% of hip patients experienced at least 1 self-reported nuisance symptom at 1 year, reporting mean satisfaction of 8.9/10 (SD, 1.7). CONCLUSION: Nuisance symptoms after hip/knee TJA are very common. Despite the high prevalence, impact on overall satisfaction is minimal and patient satisfaction remains high. Careful preoperative counseling regarding prevalence is prudent and will help establish realistic expectations following TJA.

Preliminary testing of a novel bilateral plating technique for treating periprosthetic fractures of the distal femur.

BACKGROUND: Current stabilization methods for periprosthetic fractures of the distal femur are inadequate in achieving fracture fixation, with complication rates as high as 29%. A major contributor to poor outcomes is that these methods rely only on screw purchase in the bone to maintain fracture reduction. We designed, manufactured and evaluated a novel plating method that utilizes the femoral prosthesis to enhance stability for treatment of distal femoral periprosthetic fractures. METHODS: Medial and lateral plates were designed and manufactured based on geometry of a synthetic femur and femoral prosthesis. The two plates were linked via a compression screw and a small tab on each plate that inserted into pre-existing slots on the prosthesis. Mechanical tests (500N compression or 250N anterior directed cantilever bending), were performed on synthetic femurs with simple transverse fractures (3mm gap) just superior to the distal femoral prosthesis that were stabilized using either the prototype plates or a single lateral plate. Translational movements of the fracture site during loading were measured using 3D motion tracking. FINDINGS: With the single lateral plate, the distal fragment experienced a resultant displacement of 0.40mm under cantilever bending and 0.61mm under compression (13% and 20% respectively of fracture gap width). With the bilateral plates, fracture gap motion was significantly reduced to 0.13mm under bending and compression (4.3% of the fracture gap). INTERPRETATION: Our results indicate that a bilateral plating method is capable of improving stabilization of periprosthetic fractures compared to the traditional lateral plating technique.

Computer-assisted gap equalization in total knee arthroplasty.

This in vitro biomechanical study compared a conventional balancing technique in knee arthroplasty to a technique using computer assistance. The experimental technique used a soft tissue tensioner instrumented with computer-monitored load cells to quantify soft tissue tension. To assess outcome, a tibial load transducer measured medial and lateral compartment forces and tibial rotation. An electromagnetic tracking system quantified knee position under simulated muscle loading. The computer-assisted technique improved knee balance before insertion of components. However, once components were implanted, there was no difference in knee load balance between the 2 techniques. No correlation was shown between compartmental load balance and tibial rotation or mechanical axis misalignment. Although computer-assisted surgery may improve technical accuracy, further work is necessary to achieve an optimal final knee load balance.

Efficacy and safety of controlled-release oxycodone and standard therapies for postoperative pain after knee or hip replacement.

BACKGROUND: Standard therapy (ST) for postoperative pain after knee and hip replacement at the Hamilton Health Sciences Henderson Hospital consists of epidural analgesia or patient-controlled analgesia for the first 48 hours, followed by oral or parenteral analgesics, or both, on an as-needed basis. We compared the efficacy and safety of scheduled controlled-release (CR) oxycodone hydrochloride (OxyContin; Purdue Pharma, Pickering, Ont.) and ST for postoperative pain 48 hours after primary knee and hip replacement. METHODS: In 2 separate 3-week studies of similar design, pain intensity, pain relief, length of hospital stay, analgesic use and side effects of CR oxycodone (n = 70) and ST (n = 101) were evaluated. In the CR oxycodone trial, a dose de-escalation protocol was used. RESULTS: At the time of discharge from hospital, patients in the CR oxycodone group recorded lower mean (and standard deviation) pain intensity scores than the ST group (20.2 [17.9] v. 27.7 [21.5] mm on a 100-mm visual analogue scale; p = 0.021). Length of hospital stay was 5.5 and 6.4 days for the CR oxycodone and ST groups respectively (p < 0.001). CR oxycodone patients used less opioid (morphine equivalent) while in hospital than ST patients (p < 0.001), and the average number of daily administrations of analgesics in hospital was 2.1 and 3.5 for CR oxycodone and ST patients respectively (p < 0.001). ST patients reported more nausea and vomiting, pruritus and fever than the CR oxycodone patients, but less somnolence, constipation, dizziness, confusion and tachycardia. CONCLUSIONS: CR oxycodone every 12 hours is as effective as ST in treating postoperative pain but length of hospital stay was shorter and analgesic administration in the hospital was used less frequently, providing potential hospital cost savings and reduced use of health care resources.

Single-incision, minimally invasive total hip arthroplasty: length doesn't matter.

A pilot cohort study of 60 primary total hip arthroplasties (THAs) was undertaken to evaluate the technical aspects and possible clinical advantages of performing THA through a single-incision, minimally invasive, 10-cm-length, direct lateral approach compared with the same approach performed through a standard-length skin incision. We could not show any significant difference with regard to operative time; in-hospital equianalgesic opioid consumption; postoperative blood loss; complications; hospital length of stay; or flexion, Harris Hip and Oxford Scores at 6 weeks' postoperatively. Restricting the length of skin incision for THA performed through a direct lateral approach does not appear to afford any clinical advantage to the patient in the short term. The mini-exposure creates technical challenges that have the potential to adversely affect primary THA outcome.

An in vivo biomechanical analysis of the soft-tissue envelope of osteoarthritic knees.

Soft-tissue balancing and the amount of tension applied to the ligaments in a well-functioning total knee arthroplasty (TKA) has, thus far, not been accurately quantified. A ligament-tensioning device was used to measure displacement between the tibia and femur versus load during 86 consecutive TKAs. Measurements were made in flexion and extension following bone cuts and final soft-tissue balancing to calculate mean effective stiffness (MES) of the soft-tissue envelope and mean resting force on the implanted polyethylene component. MES was not affected by age or gender and did not differ in flexion versus extension. MES was significantly higher in posterior cruciate-retaining knees compared with posterior cruciate-sacrificing knees. There was no statistical difference between mean resting force on the polyethylene in flexion versus extension, or in posterior cruciate-retaining versus -sacrificing knees. These biomechanical data will serve as a good starting point for which to compare the expected stiffness of the ligaments and resting load on the polyethylene in well-balanced knees.

Fractures at the tip of long-stem prostheses used for revision hip arthroplasty.

We report a retrospective analysis of the incidence of intraoperative femur fractures at the tip of the prosthesis in 45 consecutive, uncemented, long (205-mm), straight hydroxyapatite, fully coated stems used for revision arthroplasty of the hip. Five patients were lost to follow-up. Intraoperative fractures of the distal femur occurred in 7 cases (17.5%). In the remaining 33 cases in which no fracture occurred, the tip of the implanted stem was found to be potentially at risk for causing a fracture in 18 (55%) cases. We concluded that uncemented, 205-mm, straight femoral stems should be used with caution in the setting of revision hip surgery. A bowed stem of that length may be a safer alternative. Otherwise, a shorter, straight stem may reduce the risk of complications at the stem tip.