Activity Level Does Not Affect Survivorship of Unicondylar Knee Arthroplasty at 5-Year Minimum Follow-Up

The Million Dollar Question: Can I Return to Sports After Unicompartmental Knee Arthroplasty, Doc?

Knee osteoarthritis (OA) is a widespread and potentially debilitating condition that can interfere with the growing demand for a healthy and active lifestyle. In people under the age of 55, the prevalence of OA is expected to increase substantially in the coming decades. High tibial osteotomy and cartilage repair operations have been used to treat OA in young, active individuals; however, these procedures require lengthy rehabilitation periods and result in poor return to preoperative levels of activity that make them unsuitable for the young, active patient. Unicompartmental knee arthroplasty (UKA) is a less invasive treatment alternative, especially for younger, active, middle-aged persons with a desire to return to sporting activities. UKA yields successful return to activities with excellent functional outcomes and mid- to long-term survivorship. This article will review the ability of patients to return to sports after UKA, the type and nature of the sporting activities, as well as the timing to return to these sports.

Understanding the impact of physical activity level and sports participation on implant integrity and failure in patients following unicompartmental and total knee arthroplasty: A scoping review

Objective

Recommendations discouraging high levels of physical activity and sports following unicompartmental (UKA) and total knee arthroplasty (TKA) have been questioned in recent years. This scoping review aimed to summarize the literature examining the impact of physical activity level and sports participation on implant integrity and failure in patients following UKA and TKA.

Methods

Five databases (Medline, Embase, SCOPUS, CINAHL, ProQuest) were searched up to April 17, 2024. Retrospective, prospective and cross-sectional studies were included if they assessed the impact of physical activity level and/or sports participation (exposure variables) on implant integrity and/or failure (outcome variables) at ≥1 year following UKA or TKA. Two authors independently conducted abstract/full text reviews and data charting. Extracted data were summarized using descriptive analysis.

Results

Of 2014 potential records, 20 studies (UKA: n ​= ​6 studies, 2387 patients/TKA: n ​= ​14 studies, 7114 patients) met inclusion criteria. Following both UKA & TKA, most patients regularly participated in light to moderate physical activities and lower impact sports (e.g. walking, cycling, golf). No studies reported a deleterious effect of physical activity level or sports participation on implant integrity or failure post UKA (mean follow-up: 3.3-10.3 years). Three studies reported an association between greater levels of physical activity with increased risk of implant failure post TKA (mean follow-up: 1-11.4 years).

Conclusions

No studies demonstrated an association between greater levels of physical activity and sports participation with increased implant wear or failure post UKA, whereas results were mixed following TKA. There is a need for large, prospective cohort studies with long-term follow-up.

Comparison of survival between cemented vs cementless unicompartimental knee arthroplasty: a case control study with propensity score matching

INTRODUCTION

The first results of cementless prosthesis were rather disappointing. However recent progress in methods of cementless fixation of prosthesis should lead to better results in terms of survival of these prostheses. The main objective is to compare the survival rate at last follow-up of UKA with cemented tibial or cementless.

HYPOTHESIS

We hypothesize that UKAs with uncemented tibial implants have better survival compared to UKAs with cemented tibial implants.

MATERIAL AND METHODS

This single center case-control study included 94 medial UKA with a cemented tibial component that were paired by propensity score matching to 94 medial UKA with a uncemented tibial component. The main evaluation criterion was the comparison of the survivorship of the UKA between a cemented tibial implant and those with a cementless tibial implant in terms of all-cause revision surgery at last follow-up. The secondary endpoints were the analysis of the causes of failure.

RESULTS

The mean final follow-up was 6.1years (2.3). The overall survival rate in our serie of medial UKA was 92.4% [88.7%-96.3%] at five years. The overall survival rate in cemented group was and 91.5% [86.0%-97.3%] at five years and at 93.2% [88.1%-98.7%] at five years, in the uncemented group. No differences significant were observed in the two groups (p.value = 0.6). Only the tibial preoperative deformity was a risk factor of failure (HR: 1.11 [1.02,1.20], value = 0.02).

DISCUSSION

The use of a cemented or a cementless tibial component in a medial UKA did not influence the survival rate.

LEVEL OF EVIDENCE

III; case control study.

Small change in the arithmetic hip-knee-ankle angle during unicompartmental knee arthroplasty improves early postoperative functional outcomes

INTRODUCTION

The optimal lower-limb alignment after unicompartmental knee arthroplasty (UKA) remains controversial. This study aimed to investigate the optimal lower-limb alignment for functional improvement in the early post-UKA period. We hypothesized that a small change (Δ) in the arithmetic hip-knee-ankle (aHKA) angle during surgery would result in better postoperative knee function.

MATERIALS AND METHODS

This single-centered, retrospective study analyzed 91 patients (91 knees) who underwent UKA from April 2021 and December 2022. Preoperative and postoperative standing whole-leg radiographs were used to evaluate the mechanical HKA angle and aHKA angle. The aHKA angle was calculated from the medial proximal tibial angle (MPTA) and lateral distal femoral angle (LDFA). We defined restored aHKA angle as a postoperative aHKA angle within ± 3° of the preoperative aHKA angle. Functional improvement was evaluated using the preoperative and one-year postoperative Knee Society Scoring 2011 (KSS 2011). A multivariate regression analysis was performed to investigate the optimal lower-limb alignment for functional improvement.

RESULT

Postoperative restored aHKA angle (p = 0.020) was the only significant factor for improved KSS 2011 scores. Postoperative restored aHKA angle was obtained in 64 patients (70%). ΔMPTA (p < 0.001) and ΔLDFA (p = 0.037) were significant factors associated with a postoperative restored aHKA angle.

CONCLUSIONS

UKA restores the native knee, including resurfacing constitutional alignment and medial collateral ligament tension. Minimal change in the aHKA angle during UKA improves the functional outcomes of the knee during the early postoperative period, consistent with the minimally invasive surgical concept of UKA.

Occupational and Functional Outcomes following Patellofemoral Arthroplasty in U.S. Military Servicemembers

The functional outcomes in patients undergoing patellofemoral arthroplasty (PFA) with high occupational demands have not been fully examined. This study assessed return to work and conversion to TKA rates following PFA in a young, military cohort. Patient demographics, pain scores, and surgical information were retrospectively collected for all active-duty military members who underwent PFA over a 4-year period. The data were then analyzed to calculate return to work, conversion to TKA, and perioperative complications rates. A total of 48 servicemembers with 60 total PFAs (36 unilateral, 12 bilateral) were included, with a mean follow up of 2.2 years. At the final follow-up, 83% of servicemembers returned to military service or completed their service obligation after PFA. Conversion to TKA occurred in three (6.2%) patients at an average of 2.4 years after PFA, resulting in a PFA annual revision rate of 2.3%. The mean numeric rating scale for pain improved from 4.9 ± 2.6 at baseline to 2.5 ± 2.0 postoperatively (p < 0.001). Servicemembers with at least one prior ipsilateral knee procedure had a significantly decreased odds ratio (OR) for both occupational outcome failure (OR, 0.03; 95% confidence interval [CI], 0-0.29) and overall failure (OR, 0.13; 95% CI, 0.02-0.78). At an average of 2 years following PFA, 83% of military members returned to duty, with a low rate of revision to TKA. Prior ipsilateral knee procedure decreased the probability of medical separation. LEVEL OF EVIDENCE:  IV.

Comparison of Outcomes in High Versus Low Activity Level Patients After Total Joint Arthroplasty

BACKGROUND

Activity level (AL) recommendations following total joint arthroplasty (TJA) remain controversial. Our purpose was to compare implant survivorship of high activity (HA) and low activity (LA) patients after primary TJA. We hypothesized that there would be no difference in implant survivorship based on AL.

METHODS

This was a retrospective 1:1 matched cohort study after primary TJA with minimum 5-year follow-up. High activity patients were designated by the University of California and Los Angeles activity-level rating scale score ≥8 and matched to LA patients based on age (±5), sex, and body mass index (±5). There were 396 HA patients (149 knees and 48 hips) who met inclusion criteria. We analyzed revision rates, adverse events, and radiographic lucencies.

RESULTS

Crepitus was the most common adverse events in both HA and LA total knee arthroplasties (TKAs). Adverse events were rare in total hip arthroplasty (THA) cohorts. For both THA and TKA patients, the HA cohort did not have increased reoperations or revisions when compared to the LA cohort. No differences were noted in overall radiographic analysis between HA (16.1%) and LA (12.1%) TKA patients (P = .318), and in THA patients, more radiographic problems were noted in LA (P = .004).

CONCLUSION

We found no difference in minimum 5-year postoperative implant survivorship based on AL. This may change AL recommendations after TKA and THA.

High degree of consensus amongst an expert panel regarding focal resurfacing of chondral and osteochondral lesions of the femur with mini-implants

INTRODUCTION

The rationale for the use of mini-implants for partial resurfacing in the treatment of femoral chondral and osteochondral lesions is still under debate. The evidence supporting best practise guidelines is based on studies with low-level evidence. A consensus group of experts was convened to collaboratively advance towards consensus opinions regarding the best available evidence. The purpose of this article is to report the resulting consensus statements.

METHODS

Twenty-five experts participated in a process based on the Delphi method of achieving consensus. Questions and statements were drafted via an online survey of two rounds, for initial agreement and comments on the proposed statements. An in-person meeting between the panellists was organised during the 2022 ESSKA congress to further discuss and debate each of the statements. A final agreement was made via a final online survey a few days later. The strength of consensus was characterised as: consensus, 51-74% agreement; strong consensus, 75-99% agreement; unanimous, 100% agreement.

RESULTS

Statements were developed in the fields of patient assessment and indications, surgical considerations and postoperative care. Between the 25 statements that were discussed by this working group, 18 achieved unanimous, whilst 7 strong consensus.

CONCLUSION

The consensus statements, derived from experts in the field, represent guidelines to assist clinicians in decision-making for the appropriate use of mini-implants for partial resurfacing in the treatment of femoral chondral and osteochondral lesions.

LEVEL OF EVIDENCE

Level V.

Does high activity after total and unicompartmental knee arthroplasty increase the risk for aseptic revision?

INTRODUCTION

It has been suggested that high activity might negatively impact implant survival following total and unicompartmental knee arthroplasty (TKA/UKA) and many surgeons advise their patients to only participate in moderate level sport activities. To date, it remains unclear whether such restraints are necessary to assure longevity of the implants.

MATERIALS AND METHODS

We conducted a retrospective study on 1906 knees (1745 TKA, 161 UKA) in 1636 patients aged 45-75 years who underwent primary arthroplasty for primary osteoarthritis. Lower extremity activity scale (LEAS) at a two year follow-up was assessed to define the activity level. Cases were grouped in low (LEAS ≤ 6), moderate (LEAS 7-13) and high activity (LEAS ≥ 14). Cohorts were compared with Kruskal-Wallis- or Pearson-Chi2-Test. Univariate logistic regression was conducted to test for association between activity level at two years and later revisions. Odds ratio was reported and converted to predicted probability. A Kaplan-Meier curve was plotted to predict implant survival.

RESULTS

The predicted implant survival for UKA was 100.0% at two years and 98.1% at five years. The predicted implant survival for TKA was 99.8% at two years, 98.1% at five years. The difference was not significant (p = 0.410). 2.5% of the UKA underwent revision, one knee in the low and three knees in the moderate activity group, differences between the moderate and high activity group were not significant (p = 0.292). The revision rate in the high activity TKA group was lower than in the low and moderate activity groups (p = 0.008). A higher LEAS two years after surgery was associated with a lower risk for future revision (p = 0.001). A one-point increase in LEAS two years after surgery lowered the odds for undergoing revision surgery by 19%.

CONCLUSIONS

The study suggests that participating in sports activity following both UKA and TKA is safe and not a risk factor for revision surgery at a mid-term follow-up. Patients should not be prevented from an active lifestyle following knee replacement.

Coronal tibiofemoral subluxation under valgus stress force radiography is useful for evaluating postoperative coronal tibiofemoral subluxation in mobile-bearing UKA

PURPOSE

Coronal tibiofemoral subluxation (CTFS) is considered a controversial and potential contraindication to unicompartmental knee arthroplasty (UKA) but is less discussed. The study aims to observe the CTFS in a cohort of patients before and after mobile-bearing UKA and to investigate the relationship between preoperative variables (preoperative CTFS and preoperative CTFS under valgus stress) and postoperative CTFS after mobile-bearing UKA.

METHODS

The study retrospectively analyzed 181 patients (224 knees) undergoing mobile-bearing UKA from September 1 2019 to December 31 2021. By using hip-to-ankle anterior-posterior (AP) standing radiographs and valgus stress force radiographs, preoperative CTFS, preoperative CTFS under valgus stress, and postoperative CTFS were measured. CTFS was defined as the distance between the tangent line to the outermost joint edge of the lateral condyle of the femur and the tangent line of the lateral tibial plateau. All patients were divided into two groups based on postoperative CTFS, group A (postoperative CTFS ≤ 5 mm) and group B (postoperative CTFS > 5 mm). The Student's t-test, one-way ANOVA together with Tukey's post hoc test, the chi-square test, the Fisher's exact test, Pearson correlation analysis, simple and multiple linear regression, and univariate and multiple logistic regression were used in the analyses.

RESULTS

The means ± standard deviations (SD) of preoperative CTFS, preoperative CTFS under valgus stress, and postoperative CTFS were 4.96 ± 1.82 mm, 3.06 ± 1.37 mm, and 3.19 ± 1.27 mm. The difference between preoperative CTFS and postoperative CTFS was statistically significant (p < 0.001). The preoperative CTFS (6.35 ± 1.34 mm) in Group B (n = 22) was significantly higher than that (4.81 ± 1.82 mm) in Group A (n = 202) (p < 0.001), so was the variable-preoperative CTFS under valgus stress (5.41 ± 1.00 mm (Group B) > 2.80 ± 1.14 mm (Group A), p < 0.001). In Pearson correlation analysis, there was a correlation between preoperative CTFS and postoperative CTFS (r = 0.493, p < 0.001), while the correlation between preoperative CTFS under valgus stress and postoperative CTFS was stronger (r = 0.842, p < 0.001). In multiple linear regression analysis, preoperative CTFS under valgus stress (β = 0.798, 95% confidence interval (CI) = 0.714-0.883, p < 0.001) was significantly correlated with postoperative CTFS. In multiple logistic regression analysis, preoperative CTFS under valgus stress (OR = 12.412, 95% CI = 4.757-32.384, and p < 0.001) was expressed as the risk factor of postoperative CTFS (> 5 mm).

CONCLUSION

Preoperative CTFS can be improved significantly after mobile-bearing UKA. In addition, postoperative CTFS is correlated with preoperative CTFS under valgus stress and a higher preoperative CTFS under valgus stress will increase the risk of higher postoperative CTFS (> 5 mm).

LEVEL OF EVIDENCE

Level III.

Return to Sport After Hip and Knee Arthroplasty: Counseling the Patient on Resuming an Active Lifestyle

PURPOSEOF REVIEW

The purpose of this review is to summarize the available literature on the epidemiology, biomechanics, clinical outcomes, and complications of return to sport after TJA, as well as provide guidelines for patients' safe return to athletic activity.

RECENT FINDINGS

As volume and indications for total joint arthroplasty (TJA) expand, arthroplasty candidates today are demographically younger, more physically active, and have higher expectations for postoperative function. Many TJA patients wish to resume sports activity that may theoretically place their reconstruction under more biomechanical stress and risk for early wear or failure. Recommendations for postoperative patient activity following TJA have historically largely been surgeon-dependent and in the context of evolving prosthetic design and surgical techniques. We endorse a three-tiered framework for return to sporting activities: (1) low-impact sports are generally recommended, (2) intermediate-impact sports are generally recommended with experience, and (3) high-impact sports are generally not recommended though activity-specific joint decisions between patient and surgeon can be made.

Retrospective analysis of return to impact sport after medial unicompartmental knee arthroplasty based on a cohort of 92 patients

BACKGROUND

Return to sport after Knee Arthroplasty has been investigated reporting modifications in the physical activities with a trend towards to lower impact sports after Unicompartemental Knee Arthroplasty. The purpose of this study was to analyze the return to sport level after medial unicompartmental knee arthroplasty (MUKA) in a population of osteoarthritic patients having practiced impact sport, defined with a University of California at Los Angeles activity scale (UCLA)≥9 in their pre-symptomatic arthritic period.

HYPOTHESIS

Return to an impact sport after MUKA was possible for a population of osteoarthritic patients having practiced impact sport in their pre-symptomatic arthritic period.

METHODS

Ninety-two MUKA with a pre-symptomatic arthritic UCLA score≥9, including 60 men (65.2%) and operated between January 2009 and September 2014, were evaluated by a dedicated survey. Informations were obtained concerning the physical activities (intensity, frequency, kind of sport, reasons to decrease or stop the physical activities in the pre- and the postoperative period). The average age was 64.9 years±6.4 (range 49-74.4). Three different periods were compared: pre-symptomatic arthritic, preoperative and postoperative period. The mean follow-up was 7.3±1.7 years.

RESULTS

The mean pre-symptomatic arthritic UCLA score was 9.9±0.3, the mean preoperative UCLA score was 7.0±2.5 (2-10) and the mean postoperative UCLA score was 7.2±2.0 (3-10). There were significant differences for the mean UCLA score values between pre-symptomatic arthritis and postoperative UCLA scores (p=0.034), however no difference was detected in mean score values before and after surgery (p=0.09). Only 32.6% (30/92) of patients had a postoperative UCLA score≥9. For patients practicing an impact sport activity (UCLA≥9) in the preoperative period (23/92; 25%), the postoperative UCLA score was at 8±1.1 (range 4-10). In this subgroup, 47.8% (11/23) of patients had a postoperative UCLA score≥9. The decline in sports in postoperative was predominantly explained by residual pain of the operated knee (31/92; 34%), precaution to not damage the prosthesis (25/92; 27%) and restrictions due to another joint (19/92; 21%).

DISCUSSION

Return to impact sport after MUKA seems to be limited to a restrained number of patients. The main reasons to the decline in sporting activity level are linked to the residual pain of the operated knee and the precaution to not damage the prosthesis.

LEVEL OF EVIDENCE

IV, retrospective cohort study.

Impact of Proximal Tibial Varus Anatomy on Survivorship After Medial Unicondylar Knee Arthroplasty

BACKGROUND

Precise indications for medial unicondylar knee arthroplasty (UKA) continue to be defined. It is unclear if patients who have proximal tibia vara should be considered candidates for UKA. The purpose of this study was to evaluate the impact of proximal tibial varus alignment on outcomes after UKA.

METHODS

A retrospective review identified 2,416 patients (3,029 knees) who underwent mobile-bearing medial UKA with 2-year minimum follow-up or revision. Preoperative radiographs were evaluated, and medial proximal tibial angle (mPTA) was measured. Patients were grouped into two groups as follows: mPTA <80 degrees and mPTA ≥80 degrees. Analyses were performed on the impact of mPTA on clinical outcomes, all-cause revisions, and tibial failures.

RESULTS

At a mean follow-up of 5 years (range, 0.5 years to 12.8 years), there was not a statistically significant difference in clinical outcomes nor increased risk for all-cause revision or tibial failure in patients who had an mPTA <80°. Mean mPTA in patients who had tibial failures was 82.5° and not significantly different than those who did not have a tibial failure (82.9°) (P = .289). Tibial failure rate in knees with an mPTA <80° was 2.2% and not significantly different than knees with an mPTA ≥80° at 1.4% (P = .211). The all-cause revision rate in knees with an mPTA <80° was 5.8% and was not significantly different than knees with an mPTA ≥80° at 4.9% (P = .492).

CONCLUSION

Patients who have tibia vara are not at increased risk for tibial related or all-cause failure in medial UKA. This data may allow surgeons to increase their indications for medial UKA.

Comparable incidence of periprosthetic tibial fractures in cementless and cemented unicompartmental knee arthroplasty: a systematic review and meta-analysis

PURPOSE

(I) To determine the incidence of periprosthetic tibial fractures in cemented and cementless unicompartmental knee arthroplasty (UKA) and (II) to summarize the existing evidence on characteristics and risk factors of periprosthetic fractures in UKA.

METHODS

Pubmed, Cochrane and Embase databases were comprehensively searched. Any clinical, laboratory or case report study describing information on proportion, characteristics or risk factors of periprosthetic tibial fractures in UKA was included. Proportion meta-analysis was performed to estimate the incidence of fractures only using data from clinical studies. Information on characteristics and risk factors was evaluated and summarized.

RESULTS

A total of 81 studies were considered to be eligible for inclusion. Based on 41 clinical studies, incidences of fractures were 1.24% (95%CI 0.64-2.41) for cementless and 1.58% (95%CI 1.06-2.36) for cemented UKAs (9451 UKAs). The majority of fractures in the current literature occurred during surgery or presented within 3 months postoperatively (91 of 127; 72%) and were non-traumatic (95 of 113; 84%). Six different fracture types were observed in 21 available radiographs. Laboratory studies revealed that an excessive interference fit (press fit), excessive tibial bone resection, a sagittal cut too deep posteriorly and low bone mineral density (BMD) reduce the force required for a periprosthetic tibial fracture to occur. Clinical studies showed that periprosthetic tibial fractures were associated with increased body mass index and postoperative alignment angles, advanced age, decreased BMD, female gender, and a very overhanging medial tibial condyle.

CONCLUSION

Comparable low incidences of periprosthetic tibial fractures in cementless and cemented UKA can be achieved. However, surgeons should be aware that an excessive interference fit in cementless UKAs in combination with an impaction technique may introduce an additional risk, and could therefore be less forgiving to surgical errors and patients who are at higher risk of periprosthetic tibial fractures.

LEVEL OF EVIDENCE

V.

Does Activity Level After Primary Total Hip Arthroplasty Affect Aseptic Survival?

Background

The purpose of this study is to evaluate survivorship and outcomes of high-activity patients compared to low-activity patients after total hip arthroplasty.

Methods

A retrospective review identified 2002 patients (2532 hip) that underwent a primary total hip arthroplasty with vitamin E–infused highly crosslinked polyethylene liner. Patients were divided into 2 groups based on their University of California Los Angeles (UCLA) activity level: low activity (LA) (UCLA ≤5) and high activity (HA) (UCLA ≥6). Outcomes included Harris Hip Score, UCLA activity score, and reoperations. A multivariate nominal regression analysis was performed to evaluate the significance of postoperative activity level on survivorship.

Results

The mean follow-up duration was 4.5 years (range, 0.3 to 9.9 years). HA group had significantly higher improvements in Harris Hip Score (HHS) (P < .001) and UCLA activity score (P < .001). Aseptic revisions were performed in 2.1% of the LA group and in 0.4% hips of the HA group (P < .001). After controlling for age, gender, preoperative pain, HHS, and body mass index, a higher postoperative activity level remained a significant factor for improved aseptic survivorship with an odds ratio of 4.9 (95% confidence interval, 1.1 to 21.2, P = .03). The all-cause 5-year survivorship was 99% for the HA group and 96% to for the LA group (P < .001). The aseptic 5-year survivorship was 99.6% for the HA group and 98% for the LA group (P < .001).

Conclusions

This study found that a higher activity level after primary THA was not deleterious to survivorship at short to midterm follow-up with modern implants.

Relevance of the Tibial Slope on Functional Outcomes in ACL-Deficient and ACL Intact Fixed-Bearing Medial Unicompartmental Knee Arthroplasty

BACKGROUND

Excessive posterior tibial slope in medial unicompartmental knee arthroplasty (UKA) has been implicated in early failure. The purpose of this study was to evaluate the relationship between preoperative posterior tibial slope and postoperative slope of the implant (PSI) on outcomes in patients with anterior cruciate ligament (ACL) intact and ACL-deficient knees after fixed-bearing medial UKA.

METHODS

Patients who underwent a medial UKA between 2002 and 2017 with a minimum 3-year follow-up were included. Preoperative posterior tibial slope and postoperative PSI were measured. Outcomes measures included Knee Injury and Osteoarthritis Outcomes Score (KOOS) subscales, Lysholm, and VR-12. Failure was defined as conversion to total knee arthroplasty.

RESULTS

Of 241 knees undergoing UKA, 131 patients (70 women, 61 men; average age of 65 ± 10 years (average BMI of 27.9 ± 4) were included. For all patients, survivorship was 98% at 5 years and 96% at 10 years with a mean survival time for UKA was 15.2 years [95% CI: 14.6-15.7]. No failure had a PSI >7°. There were no superficial or deep infections. There were no significant differences in outcome scores between the ACL intact and the ACL-deficient group; therefore, the data were combined for analysis. At mean 8-year follow-up, KOOS pain scores were better in patients with PSI ≤7° (87 ± 16) than those with PSI >7° (81 ± 15). 76% of patients with PSI ≤7° reached the Patient Acceptable Symptom State for KOOS pain; whereas, 59% of patients with PSI >7° reached PASS for KOOS pain (P = .015).

CONCLUSION

Patients with postoperative posterior slope of the tibial implant >7° had significantly worse postoperative pain, without conversion to TKA, and with maintenance of high function. In ACL deficient and intact knees, nonrobotically-assisted, fixed-bearing medial UKA had a 96% survivorship at 10 years.

Robotic arm-assisted versus conventional medial unicompartmental knee arthroplasty: five-year clinical outcomes of a randomized controlled trial

Aims

Unicompartmental knee arthroplasty (UKA) is a bone-preserving treatment option for osteoarthritis localized to a single compartment in the knee. The success of the procedure is sensitive to patient selection and alignment errors. Robotic arm-assisted UKA provides technological assistance to intraoperative bony resection accuracy, which is thought to improve ligament balancing. This paper presents the five-year outcomes of a comparison between manual and robotically assisted UKAs.

Methods

The trial design was a prospective, randomized, parallel, single-centre study comparing surgical alignment in patients undergoing UKA for the treatment of medial compartment osteoarthritis (ISRCTN77119437). Participants underwent surgery using either robotic arm-assisted surgery or conventional manual instrumentation. The primary outcome measure (surgical accuracy) has previously been reported, and, along with secondary outcomes, were collected at one-, two-, and five-year timepoints. Analysis of five-year results and longitudinal analysis for all timepoints was performed to compare the two groups.

Results

Overall, 104 (80%) patients of the original 130 who received surgery were available at five years (55 robotic, 49 manual). Both procedures reported successful results over all outcomes. At five years, there were no statistical differences between the groups in any of the patient reported or clinical outcomes. There was a lower reintervention rate in the robotic arm-assisted group with 0% requiring further surgery compared with six (9%) of the manual group requiring additional surgical intervention (p < 0.001).

Conclusion

This study has shown excellent clinical outcomes in both groups with no statistical or clinical differences in the patient-reported outcome measures. The notable difference was the lower reintervention rate at five years for roboticarm-assisted UKA when compared with a manual approach.

Cite this article: Bone Joint J 2021;103-B(6):1088–1095.

Return to work after medial unicompartmental knee arthroplasty: A systematic review

INTRODUCTION

This study aims to evaluate the current literature with regard to the average time to and overall rate of return to work (RTW) following medial unicompartmental knee arthroplasty (UKA).

METHODS

A systematic search was conducted on MEDLINE (Ovid), Embase, Pubmed, CINAHL, Web of Science, Scopus, and the Cochrane Library to identify studies reporting RTW after UKA. Primary outcomes were the rate and time to RTW after UKA. Secondary outcomes were postoperative changes in work intensity, functional scores, and factors affecting RTW. Methodological quality was evaluated using the the Methodological Index for Non-Randomized Studies (MINORS) criteria.

RESULTS

Seven studies met inclusion criteria. Results were summarized qualitatively. The overall methodological quality of the studies was moderate based on the MINORS score. These studies included 636 patients with 46.5% male. Mean age was 63.1 years. The average rate of RTW was 81.7%. The average time to RTW was 5.4 ± 3.9 weeks (range 1-32 weeks). 81.8% of patients in one study returned to an equally or more physically demanding job, while 83.5% were able to work the same or longer hours postoperatively in another study. Functional scores improved after surgery (n = 6 studies). Factors affecting RTW were postoperative rehabilitation, retirement, and the effects of surgery.

CONCLUSION

Limited evidence from the included studies with moderate quality suggests that UKA allows patients to RTW faster, with a high rate of RTW and improved functional outcomes. However, consensus definitions and methods of work status analysis are needed for future studies.

Return to sports after medial unicompartmental knee arthroplasty in patients with concomitant patella-femoral osteoarthritis: multicenter retrospective cohort study with minimum 5-year follow-up

PURPOSE

The purpose of our study was to evaluate clinical outcomes and return to sports after medial unicompartmental knee arthroplasty (UKA) in middle-aged active patients with concomitant patella-femoral joint (PFJ) osteoarthritis at time of surgery.

METHODS

One-hundred and fifty-one patients who underwent medial fixed-bearing cemented UKA, between 2012 and 2015, for medial unicompartmental osteoarthritis of the knee, were retrospectively reviewed with a minimum 5-year follow-up. The mean age at surgery was 54.3 years (range 47 to 60 years). Radiological evaluation of patella-femoral joint (PFJ) osteoarthritis was performed according to Sperner classification to select a control-group (< grade III) and case-group (≥ grade III). The visual analog scale (VAS) for pain and Knee Society score (KSS) was used to evaluate preoperative and final outcomes. Physical activity level before and after the surgery was assessed by the use of UCLA score.

RESULTS

One-hundred and thirty-seven patients (89 males and 48 females) were available at last follow-up. The mean follow-up was 6.2 years (range 5.2 to 7.5 years). At last follow-up improvements of VAS and KSS scores revealed not significant correlation with PFJ osteoarthritis. The majority of patients (87.7%) returned to their sports activity after UKA surgery.

CONCLUSIONS

Improved quality of life and sports activity level resulted in middle-aged, active patients after UKAs. PFJ osteoarthritis showed no significant correlation with poorer outcomes at 5-year follow-up.

LEVEL OF EVIDENCE

III, multicenter retrospective cohort study.

Therapeutic Effects Comparison and Revision Case Analysis of Unicompartmental Knee Arthroplasty and Open Wedge High Tibial Osteotomy in Treating Medial Knee Osteoarthritis in Patients Under 60 years: A 2-6-year Follow-up Study

Objective

To evaluate the therapeutic effects and revision cases of unicompartmental knee arthroplasty (UKA) and open wedge high tibial osteotomy (OWHTO) in treating medial knee osteoarthritis (MKOA) in patients under 60 years.

Methods

The present retrospective study included a total of 192 patients who were diagnosed with MKOA and treated by UKA or OWHTO in the Second Affiliated hospital of Xi'an Jiaotong University and Xi'an Honghui Hospital between December 2012 and December 2016. Among these patients, 83 were treated by UKA (17 men and 66 women, aged 53.7 ± 5.2 years) and 109 were treated by OWHTO (23 men and 86 women, aged 51.8 ± 6.9 years). Patients were followed up at 1, 3, 6, and 12 months for the first year postoperation, and every 6 months from the second year postoperation. Basic data, perioperative data, hospital for special surgery (HSS) score, visual analogue pain score (VAS), low‐impact recovery, and revision cases of the patients were evaluated.

Results

The average follow‐up periods of the UKA group and the OWHTO group were 39.3 ± 11.2 months and 40.2 ± 13.5 months, respectively. No significant difference was found in the basic data of the two groups (P ≥ 0.05). The operative time, incision length, and dominant blood loss of the UKA group was less than those of OWHTO group by 19.6%, 10.7%, and 35.1%, respectively, and the differences were significant (P < 0.05), while no significant difference was found in postoperative in‐bed time (P ≥ 0.05). The HSS scores of the UKA group at 1 and 3 months postoperation were higher than those of the OWHTO group by 5.1% and 3.9% (P < 0.05), while no differences were found from 6 months postoperation (P ≥ 0.05). The VAS score of the UKA group 1 month postoperation was lower than that of the OWHTO group by 12.2% (P < 0.05), while no differences were found from 3 months postoperation (P ≥ 0.05). One year after the operation, most patients in both groups could not achieve ideal recovery in low‐impact sports, and no significant differences were found (P < 0.05). The sport in which most patients could not achieve ideal recovery was mountain climbing. No revision cases occurred in the OWHTO group, while two revisions occurred in the UKA group.

Conclusion

Candidates for UKA should be chosen carefully and the current indications and contraindications raised by Goodfellow should be modified.

Unicompartmental Knee Arthroplasty: US and Global Perspectives

Unicompartmental knee arthroplasty (UKA) is a treatment option for anteromedial osteoarthritis. Compared with total knee arthroplasty (TKA), UKA offers improved knee range of motion, functional recovery and decreased medical complications. Revision rates continue to be higher with UKA compared with TKA. With current UKA implants, there is no significant difference in mobile bearing or fixed bearing, or between cemented and cementless implants. Enabling technology, such as robotic-assisted surgery, has demonstrated improvements in component positioning, but no long-term difference in survival compared with traditional manual instruments.

Higher Activity Level Following Total Knee Arthroplasty Is Not Deleterious to Mid-Term Implant Survivorship

BACKGROUND

The impact of a patient's activity level following total knee arthroplasty (TKA) remains controversial, with some surgeons concerned about increased polyethylene wear, aseptic loosening, and revisions. The purpose of this study is to report on implant survivorship and outcomes of high activity patients compared to low activity patients after TKA.

METHODS

A retrospective review identified 1611 patients (2038 knees) that underwent TKA with 5-year minimum follow-up. Patients were divided in 2 groups based on their University of California Los Angeles (UCLA) activity level: low activity (LA) (UCLA ≤5) and high activity (HA) (UCLA ≥6). Outcomes included range of motion, Knee Society scores, complications, and reoperations. Parametric survival analysis was performed to evaluate the significance of activity level on survivorship while controlling for age, gender, preoperative pain, Knee Society clinical scores, Knee Society functional scores, and body mass index (BMI).

RESULTS

Mean follow-up was 11.4 years (range 5.1-15.9). The LA group had significantly more female patients, were older, had higher BMI, and had lower functional scores preoperatively (all with P < .001). The HA group had significantly higher improvements in Knee Society scores (P < .001) and pain postoperatively (P < .001). Revisions were performed in 4% of the LA group and 1.7% knees of the HA group (P = .003). After controlling for age, gender, preoperative pain, Knee Society clinical scores, Knee Society functional scores, and BMI, a higher postoperative activity level remained a significant factor for improved survivorship with an odds ratio of 2.4 (95% confidence interval 1.2-4.7, P = .011). The all-cause 12-year survivorship was 98% for the HA group and 95.3% for the LA group (P = .003). The aseptic 12-year survivorship was 98.4% for the HA group and 96.3% for the LA group (P = .02).

CONCLUSION

Highly active patients had increased survivorship at 5-year minimum follow-up compared to lower activity patients after TKA. Patient activity level after TKA may not need to be limited with modern implants.