Unicompartmental and total knee arthroplasty in the over 70 population

Cementless Total Knee Arthroplasty: Does Age Affect Survivorship and Outcomes?

BACKGROUND

Despite the growing popularity of cementless total knee arthroplasty (TKA) in younger patients, the outcomes are unclear in the elderly population. We aimed to compare the clinical outcomes and survivorship of cementless TKA between different age groups.

METHODS

Utilizing our prospectively collected institutional database, we retrospectively reviewed all patients undergoing primary cementless TKAs at a tertiary care institute. We identified 347 TKA, which were divided into 3 groups based on age at the time of surgery. Group A was ≤ 60 years, Group B was 60 to ≤ 70 years, and Group C was > 70 years. We compared clinical outcomes (Knee Society Clinical Rating System [KSCRS], Western Ontario and McMaster University Osteoarthritis Index [WOMAC], and Veterans Rand 12 Item Health Survey [VR-12]) and survivorship between the groups.

RESULTS

At final follow-up, range of motion, KSCRS, WOMAC, and VR-12 physical score were comparable (P > .05). The VR-12 Mental score was higher in Group B and Group C than in Group A (P = .003). Compared to preoperative scores, the change in KSCRS, WOMAC, and VR-12 physical and mental scores was comparable at the final follow-up (P > .05). No patient underwent revision for aseptic loosening.

CONCLUSIONS

There were no cases of revision surgery for aseptic loosening in our cohort of 347 cementless TKAs. Patients > 70 years of age undergoing cementless TKA can achieve clinical scores equivalent to those of younger patients at short term (2-year) follow-up. Longer-term survivorship is still required, but based on early data, cementless TKA can be a safe option for older patients.

Patients With Significant Medical Comorbidities May Benefit from Unicompartmental Knee Arthroplasty Over Total Knee Arthroplasty

Many studies have compared outcomes in total knee arthroplasty (TKA) versus unicompartmental knee arthroplasty (UKA); however, to the authors' knowledge, there is no study evaluating complication rates in patients with significant comorbidities. The purpose of this retrospective study was to compare the incidence of postoperative complications, readmission and reoperation rates, length of stay (LOS), and discharge location for patients with significant medical comorbidities undergoing TKA versus UKA. Using the NSQIP database from 2008 to 2018, patients were identified by CPT code (27447 or 27446) and admission diagnostic code of primary osteoarthritis and included in the study if they had an American Society of Anesthesia score greater than or equal to 3. Chi-square test was used to compare categorical variables and t-test for continuous variables. Multivariate regression was used to compare outcomes of interest between groups. A total of 167,054 patients were analyzed with 97.3% undergoing TKA. TKA patients had a greater overall complication rate than those undergoing UKA (p < 0.001). Readmission rates were approximately 1.5 times higher in TKA compared with UKA (p = 0.002), while no statistically significant difference was discovered in reoperation rates (p = 0.868). TKA was also associated with decreased rates of same day discharge, discharge within 24 hours of surgery, and discharge home (p < 0.001, <0.001, and <0.001, respectively). This study found an increase in complication rates, readmission rates, and LOS, along with a lower likelihood of discharge home when undergoing a TKA. These findings suggest that patients with significant medical comorbidities at baseline may benefit from UKA over TKA when anatomically indicated.

Can single-stage bilateral unicompartmental knee arthroplasty be safely performed in patients over 70?

Background

For patients with bilateral, symptomatic unicompartmental knee arthritis, single-stage bilateral unicompartmental knee arthroplasty (ssBUKA) presents an attractive option. However, most studies have examined younger patient cohorts and the safety of ssBUKA remains controversial for older individuals. Therefore, the purpose of this study was to compare complication rates following ssBUKA for patients ≤70 and > 70 years old.

Methods

A retrospective chart review of 238 patients having undergone ssBUKA was performed, including 134 patients ≤70 and 104 patients >70. Post-operative complications were recorded at the six-week post-operative visit, along with emergency room visits and hospital readmissions within 90 days.

Results

Compared to patients ≤70, patients >70 were more frequently female (43.3% and 55.8%, respectively) (p = 0.037) and had significantly lower body mass index (30.41 ± 4.64 and 27.30 ± 3.68, respectively) (p < 0.001). Patients >70 were discharged home (50%) less commonly than patients ≤70 (73.1%) (p < 0.001). Two patients ≤70 (1.5%) and two patients >70 (1.9%) sought emergency room treatment (p = 0.589), with respiratory complications most common. There were no differences regarding any postoperative complications between patients ≤70 and > 70 years old.

Conclusion

These results suggest that patients >70 can safely undergo ssBUKA, as it does not appear to increase the incidence of early post-operative complications compared to patients ≤70. However, 50% of patients >70 were not able to discharge directly home following surgery.

Unicompartmental Knee Arthroplasty in Octogenarians versus Younger Patients: A Comparison of 30-Day Outcomes

As the United States' octogenarian population (persons 80-89 years of age) continues to grow, understanding the risk profile of surgical procedures in elderly patients becomes increasingly important. The purpose of this study was to compare 30-day outcomes following unicompartmental knee arthroplasty (UKA) in octogenarians with those in younger patients. The American College of Surgeons National Surgical Quality Improvement Program database was queried. All patients, aged 60 to 89 years, who underwent UKA from 2005 to 2016 were included. Patients were stratified by age: 60 to 69 (Group 1), 70 to 79 (Group 2), and 80 to 89 years (Group 3). Multivariate regression models were estimated for the outcomes of hospital length of stay (LOS), nonhome discharge, morbidity, reoperation, and readmission within 30 days following UKA. A total of 5,352 patients met inclusion criteria. Group 1 status was associated with a 0.41-day shorter average adjusted LOS (99.5% confidence interval [CI]: 0.67-0.16 days shorter, p < 0.001) relative to Group 3. Group 2 status was not associated with a significantly shorter LOS compared with Group 3. Both Group 1 (odds ratio [OR] = 0.15, 99.5% CI: 0.10-0.23) and Group 2 (OR = 0.33, 99.5% CI: 0.22-0.49) demonstrated significantly lower adjusted odds of nonhome discharge following UKA compared with Group 3. There was no significant difference in adjusted odds of 30-day morbidity, readmission, or reoperation when comparing Group 3 patients with Group 1 or Group 2. While differences in LOS and nonhome discharge were seen, octogenarian status was not associated with increased adjusted odds of 30-day morbidity, readmission, or reoperation. Factors other than age may better predict postoperative complications following UKA.

Using MRI Measurement to Improve Accuracy of Femoral Component Sizing in Oxford Unicompartmental Knee Arthroplasty

Unicompartmental knee arthroplasty (UKA) can achieve better kinematics and faster recovery than total knee arthroplasty. The Phase III Oxford UKA system has five sizes of femoral components to approximate the normal knee geometry. However, these different sizes may also induce problems, such as the misselection of component size. Different criteria have been proposed to predict the ideal size preoperatively. However, no single method can be applied universally. Therefore, this study aimed to develop a preoperative measurement using knee magnetic resonance imaging (MRI) to predict femoral component size. A total of 68 patients who underwent UKA were investigated from June 2019 to April 2020. 16 knees using a different MRI protocol were excluded. We developed an MRI measurement method to determine femoral size instead of gender- and height-based methods. The accuracy of different methods was compared using postoperative true lateral view radiographs. Three different kinds of gender- and height-based criteria, preoperative templating and intraoperative spoon measurement were compared. The accuracy of MRI measurement was 90.3%. Therefore, a significant difference was found between MRI measurements and all other methods, such as templating or gender- and height-based methods. In conclusion, the MRI measurement method can be concluded to accurately predict femoral component size in UKA. This method could be used regardless of different ethnic groups, individual knee geometry, or soft tissue tension.

A meta-analysis of clinical and radiological outcomes in simultaneous bilateral unicompartmental knee arthroplasty

BACKGROUND

The most common pattern seen in bilateral knee osteoarthritis involves only the medial compartment in both knees. In such cases, bilateral Unicompartmental Knee Arthroplasty (UKA) would be a suitable surgery, this can be done simultaneously in one surgery or in stages with a period of time between each UKA. Simultaneous bilateral UKA in appropriately selected patients have the potential advantages of a lower cost, a shorter hospital stay, and a shorter overall recovery process. Despite this, there are concerns that operating on both knees in one surgery may increase the risk of complications, revisions and mortality.

METHODS

A PRISMA systematic review and meta-analysis was conducted using three databases (MEDLINE, EMBASE, and Scopus) to identify all studies which investigated either clinical or radiological outcomes in simultaneous bilateral UKA.

RESULTS

All sixteen studies included found that simultaneous bilateral UKA improved clinical and radiological outcomes. Eight studies compared clinical or radiological outcomes between simultaneous and staged bilateral UKA. Simultaneous bilateral UKA was found to have a significantly shorter length of operation, length of hospital stay, and a lower treatment cost (P < 0.001). Our meta-analysis found no statistically significant difference in the all-cause complication rate between simultaneous and staged bilateral UKA (P = 0.36). Only one study compared radiological outcomes between simultaneous and staged bilateral UKA which found no significant difference.

CONCLUSION

Our review suggests that simultaneous bilateral UKA is comparable to staged bilateral UKA in terms of clinical and radiological outcomes and has the potential to be increasingly adopted in clinical practice due to its superior cost-effectiveness.

Early Postoperative Pain Predicts 2-Year Functional Outcomes following Knee Arthroplasty

Pain control following knee arthroplasty is extremely important to both patients and surgeons to improve the perioperative experience; however, the implication of early pain control on long-term outcomes following knee arthroplasty remains poorly understood. We hypothesized that poor early pain control results in poor functional outcomes 2 years following total (TKA) and unicondylar knee arthroplasty (UKA). This retrospective study reviewed 242 TKA and 162 UKA performed at a single institution by two surgeons. Mean visual analog scale (VAS) pain scores were collected for first 3 postoperative days. Patients were prospectively evaluated using short form (SF-12), the Western Ontario and McMaster University osteoarthritis index (WOMAC), and the Knee Society functional score (KSFS) questionnaires. Pearson's correlation coefficients were calculated between mean VAS pain scores and functional outcome scores at 2 years. In the TKA group, poorly controlled perioperative pain correlated with poorer functional scores at 2 years. There was a significant negative correlation between early mean VAS pain scores (mean, 3.2 ± 2.0) and most 2-year functional outcomes including SF-12 physical score (r = -0.227, p ≤ 0.01), WOMAC pain scores (r = -0.268, p ≤ 0.01), WOMAC stiffness scores (r = -0.224, p < 0.01), WOMAC function score (r = -0.290, p 0.01), and KSFS (r = -0.175, p = 0.031). Better control of early pain was associated with improved functional outcomes at 2 years following TKA. We also found significant negative correlations between preoperative functional scores and early postoperative pain scores. Collectively, using preoperative and early postoperative pain scores, we identified an "at-risk" patient group that manifested an inferior functional outcome at 2 years; these patients may benefit from closer surveillance and a multidisciplinary approach to pain and function to optimize their clinical outcome following knee arthroplasty.

Quality of life outcomes in patients undergoing knee replacement surgery: longitudinal findings from the QPro-Gin study

Background

Many patients report postoperative pain, limited improvement in physical function and poor quality of life (QOL) after knee replacement surgery. Our study uses baseline predictors of change to investigate the QOL of patients with knee osteoarthritis 3-months after knee replacement surgery.

Methods

A prospective observational study was designed to evaluate patients (n = 132) scheduled for uni-compartmental or total knee replacement surgery who were assessed at baseline (preoperatively) and 3-months after. Physical and mental endpoints based on the component scores of the SF-12 and on the Western Ontario and McMaster Universities Arthritis (WOMAC) index were used to investigate patients’ QOL. Generalised estimating equation methodology was used to assess patients’ baseline characteristics (age, sex, education, body mass index (BMI), comorbidity, depressive symptoms, cognitive impairment, smoking/alcohol and type of surgery), the study endpoints and their changes over a 3-month post-surgery period. Stratified analyses by rehabilitation status after discharge were performed.

Results

Longitudinal data analysis showed that the baseline factors associated with improvement in general QOL at the 3-month post-surgery assessment were higher BMI, a high comorbidity, total (as opposed to unicompartmental) knee replacement and low education level. Data analysis of the patients who underwent rehabilitation after discharge revealed that the current smokers’ physical QOL worsened over time. The general QOL was unchanged over time in the presence of depressive symptomatology.

Conclusions

These findings underline the importance of using comprehensive assessment methods to identify factors affecting functionality and QOL, and developing interventions to improve the health/wellbeing of patients after knee replacement.

Patient relevant outcomes of unicompartmental versus total knee replacement: systematic review and meta-analysis

OBJECTIVE

To present a clear and comprehensive summary of the published data on unicompartmental knee replacement (UKA) or total knee replacement (TKA), comparing domains of outcome that have been shown to be important to patients and clinicians to allow informed decision making.

DESIGN

Systematic review using data from randomised controlled trials, nationwide databases or joint registries, and large cohort studies.

DATA SOURCES

Medline, Embase, Cochrane Controlled Register of Trials (CENTRAL), and Clinical Trials.gov, searched between 1 January 1997 and 31 December 2018.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies published in the past 20 years, comparing outcomes of primary UKA with TKA in adult patients. Studies were excluded if they involved fewer than 50 participants, or if translation into English was not available.

RESULTS

60 eligible studies were separated into three methodological groups: seven publications from six randomised controlled trials, 17 national joint registries and national database studies, and 36 cohort studies. Results for each domain of outcome varied depending on the level of data, and findings were not always significant. Analysis of the three groups of studies showed significantly shorter hospital stays after UKA than after TKA (-1.20 days (95% confidence interval -1.67 to -0.73), -1.43 (-1.53 to -1.33), and -1.73 (-2.30 to -1.16), respectively). There was no significant difference in pain, based on patient reported outcome measures (PROMs), but significantly better functional PROM scores for UKA than for TKA in both non-trial groups (mean difference -0.58 (-0.88 to -0.27) and -0.32 (-0.48 to -0.15), respectively). Regarding major complications, trials and cohort studies had non-significant results, but mortality after TKA was significantly higher in registry and large database studies (risk ratio 0.27 (0.16 to 0.45)), as were venous thromboembolic events (0.39 (0.27 to 0.57)) and major cardiac events (0.22 (0.06 to 0.86)). Early reoperation for any reason was higher after TKA than after UKA, but revision rates at five years remained higher for UKA in all three study groups (risk ratio 5.95 (1.29 to 27.59), 2.50 (1.77 to 3.54), and 3.13 (1.89 to 5.17), respectively).

CONCLUSIONS

TKA and UKA are both viable options for the treatment of isolated unicompartmental osteoarthritis. By directly comparing the two treatments, this study demonstrates better results for UKA in several outcome domains. However, the risk of revision surgery was lower for TKA. This information should be available to patients as part of the shared decision making process in choosing treatment options.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO number CRD42018089972.

Bearing Dislocation and Progression of Osteoarthritis After Mobile-bearing Unicompartmental Knee Arthroplasty Vary Between Asian and Western Patients: A Meta-analysis

BACKGROUND

Implant survivorship is reported to be lower and complications, particularly bearing dislocation, are reported to be more frequent in Asian than in Western patients with medial knee osteoarthritis (OA) undergoing Oxford® Phase III unicompartmental knee arthroplasty (UKA). To date, however, these complications have not been compared between these groups of patients.

QUESTIONS/PURPOSES

The purpose of this study was to perform a meta-analysis comparing the standardized incidence rates of (1) all-cause reoperation; (2) reoperation related to bearing dislocation; and (3) reoperation related to progression of lateral compartment arthritis in Asian and Western patients with medial knee OA who underwent Oxford Phase III UKA.

METHODS

We searched MEDLINE® (January 1, 1976, to May 31, 2017), EMBASE® (January 1, 1985, to May 31, 2017), and the Cochrane Library (January 1, 1987, to May 31, 2017) for studies that reported complications of Oxford Phase III UKAs. Studies were included if they reported reoperation rates attributable to bearing dislocation and/or progression of lateral knee OA after surgery with this implant. Twenty-seven studies were included in this systematic review and 16 studies with followups > 5 years were included in the meta-analysis. These rates were converted to standardized incidence rate (that is, reoperations per 100 observed component years) based on mean followup and number of involved knees in each study. After applying prespecified inclusion and exclusion criteria, the studies were categorized into two groups, Asian and Western, based on hospital location. Twenty-five studies, containing 3152 Asian patients and 5455 Western patients, were evaluated. Study quality was assessed by the modified Coleman Methodology score (MCMS). Although all studies were Level IV, their mean MCMS score was 66.92 (SD, 8.7; 95% confidence interval [CI], 63.5-70.3), indicating fair quality. Because the heterogeneity of all subgroup meta-analyses was high, a random-effects model was used with estimations using the restricted maximum likelihood method.

RESULTS

There was no difference in the proportion of Asian patients versus Western patients undergoing reoperation for any cause calculated as 100 component observed years (1.022 of 3152 Asian patients; 95% CI, 0.810-1.235 versus 1.300 of 5455 Western patients; 95% CI, 1.067-1.534; odds ratio, 0.7839; 95% CI, 0.5323-1.1545; p = 0.178). The mean reoperation rate attributable to bearing dislocation per 100 observed years was higher in Asian than in Western patients (0.525; 95% CI, 0.407-0.643 versus 0.141; 95% CI, 0.116-0.166; odds ratio, 3.7378; 95% CI, 1.694-8.248; p = 0.001) Conversely, the mean reoperation rate attributable to lateral knee OA per 100 observed years was lower in Asian than in Western patients (0.093; 95% CI, 0.070-0.115 versus 0.298; 95% CI, 0.217-0.379; odds ratio, 0.3114; 95% CI, 0.0986-0.9840; p < 0.001).

CONCLUSIONS

Although total reoperation rates did not differ in the two populations, reoperation for bearing dislocation was more likely to occur in Asian than in Western patients, whereas reoperation for lateral knee OA progression was more likely to occur in Western than in Asian patients after Oxford Phase III UKA. Although possible explanations for these findings may be hypothesized, additional randomized, prospective comparative studies are needed. However, better survival outcomes after UKA may require consideration of ethnicity and lifestyle choices in addition to traditional surgical technique and perioperative care.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Bilateral simultaneous unicompartmental knee arthroplasty versus unilateral total knee arthroplasty: A comparison of the amount of blood loss and transfusion, perioperative complications, hospital stay, and functional recovery

BACKGROUND

Unicompartmental knee arthroplasty (UKA) is a good alternative treatment option to total knee arthroplasty (TKA) for single compartment knee osteoarthritis. Several recent reports suggest that UKA results in more rapid functional recovery than TKA, together with fewer complications. Few performed a comparison of bilateral simultaneous UKA and unilateral TKA.

HYPOTHESIS

Bilateral simultaneous UKA would result in fewer perioperative complications, less blood loss, less transfusion and faster recovery of short-term clinical outcomes, compared with unilateral TKA patients.

MATERIAL AND METHODS

In a retrospective trial, the bilateral simultaneous UKA (bUKA) cases were matched one to one with a cohort of unilateral TKA (uTKA) cases according to age, body mass index, gender, Kellgren-Lawrence grade of knee osteoarthritis and American Society of Anesthesiologists score. In bilateral simultaneous UKA group, patients had KL grade 4 of bilateral knee osteoarthritis, and in unilateral TKA group, patients had KL grade 4 of unilateral knee osteoarthritis. The transfusion requirements, estimated blood loss (EBL), duration of hospital stay, incidence of complications, and knee clinical scores of the bUKA and uTKA groups were compared at the 6-month short-term follow-up.

RESULTS

Patients were categorized into the bUKA group (n=52) and uTKA group (n=52). The number of patients requiring transfusion and the amount of EBL was smaller in the bUKA group (P<0.001 for transfusion and P=0.043 for EBL). The duration of hospital stay was shorter and the number of complications was smaller in the bUKA group (P<0.001 for hospital stay and P=0.028 for complications). The clinical outcomes were also superior in the bUKA group (P<0.001).

CONCLUSIONS

Bilateral simultaneous UKA shows fewer perioperative complications, less blood loss, less transfusion, and better functional outcomes at 6 months postoperatively than unilateral TKA. The data suggest that bilateral simultaneous UKA can be performed safely, and results in acceptable clinical outcomes.

LEVEL OF EVIDENCE

III, case-control study.

Unicompartmental Knee Arthroplasty vs Total Knee Arthroplasty for Medial Compartment Arthritis in Patients Older Than 75 Years: Comparable Reoperation, Revision, and Complication Rates

BACKGROUND

Prior studies comparing unicompartmental knee arthroplasty (UKA) with total knee arthroplasty (TKA) in the elderly are limited by heterogeneity in arthritic disease patterns and patient selection. We report the results of UKA and TKA in patients 75 years and older with isolated medial compartmental arthritis, with special emphasis on immediate postoperative recovery, complications, reoperation rates, and implant survivorship at midterm follow-up.

METHODS

A retrospective review was performed of all patients 75 years and older who underwent UKA or TKA at our institution between 2002 and 2012. All TKA preoperative X-rays were reviewed by a blind observer to identify knees with isolated medial compartmental arthritis considered acceptable candidates for UKA. Patients with less than 2 years of follow-up, flexion contracture greater than 10°, and rheumatoid arthritis were excluded. The final sample included 120 UKA (106 patients) and 188 TKA (170 patients) procedures. Patient records were reviewed to determine early postoperative recovery, complications, reoperations for any reason, and implant survivorship.

RESULTS

UKA patients experienced significantly shorter operative time, shorter hospital stay, lower intraoperative estimated blood loss, lower postoperative transfusions, greater postoperative range of motion, and higher level of activity at time of discharge. Two UKA and 2 TKA patients required revision surgery. There was no statistically significant difference in postoperative Knee Society Scores. There were no differences in 5-year survivorship estimates.

CONCLUSION

Due to its less invasive nature, patients older than 75 undergoing UKA demonstrated faster initial recovery when compared to TKA, while maintaining comparable complications and midterm survivorship. UKA should be offered as an option in the elderly patient who fits the selection criteria for UKA.

Unicondylar knee arthroplasty: Key concepts

The concept of unicondylar knee arthroplasty (UKA) has been described as early as 1950s following the introduction of the MacIntosh and McKeever hemiarthroplasty. With improvements in implant design, patient selection, and surgical technique, there has been an increase in utilization of UKA as a less-invasive alternative to total joint arthroplasty for the treatment of localized symptomatic osteoarthritis. The purpose of this review article is to highlight five trending concepts in UKA based on current evidence: bearing design, fixation technique, medial vs. lateral UKA, implant survivorship, and revision surgery.

Superior alignment but no difference in clinical outcome after minimally invasive computer-assisted unicompartmental knee arthroplasty (MICA-UKA)

PURPOSE

Variety of clinical trials have been published comparing the alignment of MICA-UKA with MI-UKA. However, to the best of our knowledge, no published study has showed whether radiological alignment by MICA-UKA has influence on the clinical results. The present study was conducted to compare the short-term results of MICA-UKA with MI-UKA. It was hypothesized that better alignment as well as clinical results was achieved by MICA-UKA as compared to MI-UKA.

METHODS

The clinical and radiological results of 87 subjects who underwent primary UKA using either minimally invasive and computer-assisted technique (45 patients Group A) or minimally invasive technique (42 patients, Group B) were reported. Knee Society scores (KSSs), Knee Society functional scores (KSFSs), range of motion (ROM), and radiographic results were assessed and reported preoperatively and at 24-month follow-up. Total blood loss, operative time, and length of skin incision were compared.

RESULTS

The accuracy of the implantations in relation to the coronal mechanical axis in Group A was significantly superior to that of Group B (P = 0.033). The femoral rotational profile revealed the prosthesis in Group A that was implanted with significantly less internal rotation than Group B (P = 0.025). Clinical results, with regard to ROMs and KSSs, as well as KSFSs were equally good in both the groups. The average blood loss in patients of Group A was significantly reduced as compared to patients of Group B. No significant difference was detected in terms of operative time or length of skin incision.

CONCLUSIONS

It is suggested that MICA-UKA improves the implant alignment without increasing clinical results versus MI-UKA. We advocate that computer navigation should be considered when minimally invasive unicompartmental knee arthroplasty is performed.

LEVEL OF EVIDENCE

Therapeutic study, Level II.

Lower limb alignment control: is it more challenging in lateral compared to medial unicondylar knee arthroplasty?

INTRODUCTION

Limb alignment after unicondylar knee arthroplasty (UKA) has a significant impact on outcomes. The literature lacks lateral UKA alignment studies, making our understanding of this issue based on medial UKA.

METHODS

We evaluated limb alignment in 241 patients who underwent medial (229 knees) or lateral (37 knees) UKA. Alignment was measured pre and postoperatively in radiographs and intra-operatively using a navigation system. We compared the percentage of over-correction and the difference between post-operative alignment and navigation measurement.

RESULTS

Percentage of overcorrection was significantly higher in the lateral UKAs (11%) compared to the medial UKAs (4%). In medial UKAs, the mean difference between the intraoperative alignment and the post-operative was 1.33°. This was significantly lower than the mean 1.86° difference in the lateral UKAs.

CONCLUSIONS

Our data demonstrated an increased risk of "overcorrection," and greater difficulty in predicting postoperative alignment using computer navigation, when performing lateral UKAs compared to medial UKAs.

An Analysis of Risk Factors for Short-Term Complication Rates and Increased Length of Stay Following Unicompartmental Knee Arthroplasty

BACKGROUND

Unicompartmental knee arthroplasty (UKA) is an increasingly popular procedure, with excellent long-term outcomes. However, there are only a limited number of reports reporting its short-term morbidity and mortality.

QUESTIONS/PURPOSES

We sought to analyze the reported 30-day morbidity, mortality, and risk factors for complications and prolonged length of stay (>4 days) following UKA.

PATIENTS AND METHODS

Utilizing the National Surgical Quality Improvement Program (NSQIP) database, including patients (n = 2316) from 2005-2012, we correlated the reported 30-day complications and prolonged length of stay with patient demographics and risk factors.

RESULTS

The overall rate of complications was low (3.2%). The distribution of complications demonstrated 0.5% major systemic, 1.4% minor systemic, 0.7% major local, and 0.9% minor local complications, with a 2.1% readmission rate. Multivariate regression demonstrated increased BMI and a history of chronic obstructive pulmonary disease (COPD) as independent risk factors for complications. Furthermore, multivariate regression demonstrated increased BMI, ASA ≥ 3, history of COPD, recent operation, and postoperative transfusion as independent risk factors for prolonged length of hospitalization.

CONCLUSIONS

Utilizing the NSQIP, we present one of the largest studies to date evaluating complications following UKA. Our multivariate model demonstrated obesity and COPD to be the risk factors for complications while obesity, ASA ≥ 3, COPD, recent operation, and blood transfusion to be the risk factors for prolonged length of stay.

Treatment of osteoarthritis of the middle-aged athlete

Unicompartmental knee arthroplasty (UKA) has increasingly become an attractive alternative to total knee arthroplasty for early intervention. Clinical and biomechanical studies have shown that UKA offers advantages in early recovery, more natural function, and patient satisfaction. The literature has also shown that UKA exhibits a higher rate of revision than total knee arthroplasty, particularly in registry studies that include patients from outside of high-volume specialty centers. Patient-specific UKA offers the potential to close the gap between the known advantages of a partial knee solution and the documented risk of early revision. On the basis of the patient's own imaging data, patient-specific UKA allows for an anatomically matched implant design that provides personalized fit, full coverage of the tibial cortical rim, and preserves the femoral articulating geometry. These design advantages are paired with a patient-specific instrument system that provides reliable component placement and simplified balancing.

Total knee arthroplasty has higher postoperative morbidity than unicompartmental knee arthroplasty: a multicenter analysis

A total of 2235 primary total knee arthroplasties (TKAs) and 605 unicompartmental knee arthroplasties performed at 3 institutions over 5 years were reviewed to compare the incidence of postoperative complications between these groups. The overall risk of complications for patients undergoing TKA was 11.0%, compared with 4.3% for patients undergoing unicompartmental knee arthroplasty (P < .0001). Total knee arthroplasty was associated with increased rates of manipulation (odds ratio [OR], 13.0; P < .0001), transfusion (OR, 8.5; P = .036), intensive care unit admission (OR, 7.4; P = .049), discharge to a rehabilitation facility (OR, 5.2; P < .0001) and had longer hospital stays (mean, 3.3 vs 2.0 days; P < .0001). There was a trend toward an increased risk of deep infection (0.8% vs 0.2%, P = .13), readmission (4.2% vs 2.7%, P = .0795), thromboembolic events (1.0% vs 0.64%, P = .398), and any reoperation (1.4% vs 0.6%; P = .064). The increased risk of perioperative complications after TKA should be considered when counseling patients if they are an appropriate candidate for either procedure.

How to read a postoperative knee replacement radiograph

Knee replacement surgery is the most common joint replacement surgery in England and Wales. Postoperative radiographs are associated with long-term outcome at both early and late stages, and their correct interpretation is therefore vital. These radiographs will commonly be assessed by surgical trainees, emergency doctors, orthopaedic surgeons, nurse practitioners, and radiologists. The aim of this paper is to provide the reader with a systematic approach to assessing these radiographs, whether it be in the immediate postoperative period or during subsequent follow-ups, and to provide sufficient knowledge to critique the procedure. An outline of prostheses and their indications alongside a comprehensive review of the assessment of important angles, alignment, and correct positioning of femoral and tibial components is presented.