The Lawrence D. Dorr Surgical Techniques & Technologies Award: Patient Acceptable Symptom State (PASS) in Medial and Lateral Unicompartmental Knee Arthroplasty: Does the Status of the ACL Impact Outcomes?

Comparison of the clinical efficacy of lateral versus medial unicondylar replacement for unicompartmental osteoarthritis of the knee: a meta-analysis

OBJECTIVE

This meta-analysis evaluates the comparative efficacy of lateral unicompartmental arthroplasty (UKA) versus medial UKA in treating unicompartmental knee osteoarthritis (KOA).

METHODS

We systematically searched Cochrane, PubMed, Embase, and Web of Science databases from January 2000 to September 2024. Literature screening, quality assessment, and data extraction were conducted based on predefined inclusion and exclusion criteria. Review Manager 5.4 software was used to analyze postoperative functional scores, pain scores, aseptic loosening, progression of contralateral arthritis, and prosthesis survival.

RESULTS

Fifteen cohort studies, encompassing 2,592 knees with medial UKA and 614 knees with lateral UKA, were included. The analysis showed no statistically significant differences in functional scores [SMD = 0.11, 95% CI (- 0.10, 0.33), I2 = 64%, P = 0.31], pain scores [SMD = 0.23, 95% CI: (- 0.22, 0.67), I2 = 91%, P = 0.32], aseptic loosening [OR = 1.33, 95% CI: (0.31, 5.78), I2 = 0%, P = 0.70], progression of contralateral arthritis [OR = 0.37, 95% CI: (0.07, 1.91), I2 = 0%, P = 0.23], short- to intermediate-term survival [OR = 1.40, 95% CI: (0.84, 2.35), I2 = 0%, P = 0.20], and long-term survival [OR = 1.12, 95% CI: (0.61, 2.05), I2 = 0%, P = 0.70].

CONCLUSION

Our findings indicate no significant differences in functional outcomes, pain relief, aseptic loosening, progression of contralateral arthritis, or prosthesis survival between lateral and medial UKA. Thus, both approaches are reliable options for patients with unicompartmental KOA.

Unicompartmental knee arthroplasty implant survival in patients with borderline indications

INTRODUCTION

In the literature, 80%-92% of patients are satisfied with their medial femorotibial unicompartmental knee arthroplasties (UKAs). These results are associated with a 10-year implant survival rates ranging from 94% to 98% in various studies. Such outcomes are generally reported after excluding patients with obesity, chronic anterior instability, frontal deformities, or preoperative knee flexion deformities exceeding 10 °. These contraindications remain controversial in the literature. The primary objective of this study was to compare the survival rates of implants used for medial femorotibial UKA performed under borderline indications with those of procedures performed under conventional indications and to identify the prognostic factors for revision surgery.

HYPOTHESIS

We hypothesized that the survival of medial femorotibial UKAs is not impacted by these contraindications.

MATERIALS AND METHODS

This was a retrospective, single-center, observational, epidemiological study. All consenting patients who underwent medial femorotibial UKA between 2009 and 2015 were included. Patients who underwent other types of arthroplasties concurrently were excluded. The primary evaluation criterion was implant survival, which was characterized by no need for revision surgery. The borderline indications were defined as follows: obesity (Body Mass index BMI > 30), anterior cruciate ligament (ACL) deficiency, preoperative lower limb frontal deviation ≥10 °, or preoperative flexion deformity ≥10 °.

RESULTS

A total of 468 patients were included, and the average follow-up duration was 8.5 years [7.1; 10.3]. Among them, 270 (57.7%) underwent UKA under at least one borderline indication, whereas 198 (42.3%) underwent UKA under conventional indications. Forty revision surgeries were recorded, and the average time to revision surgery was 26 months. No statistically significant difference in survival was observed between patients with borderline indications and those with conventional indications. Multivariate analysis revealed that obesity (HR = 3.0 [1.5-5.7]) and ACL deficiency (HR = 3.5 [1.4-8.8]) significantly increased the risk of revision surgery.

DISCUSSION

This study revealed no significant difference in survival between UKAs performed under borderline versus conventional indications. Larger studies are needed to confirm these findings.

LEVEL OF EVIDENCE

IV; retrospective observational study. Mots clés: genou, arthroplastie, obésité, ostéoarthrite, survie.

The outpatient experience in unicompartmental knee arthroplasty: How to perform safely in the ambulatory surgery center

The number of outpatient unicompartmental knee arthroplasty (UKA) procedures has increased substantially over the last decade. The ambulatory surgery center (ASC) and hospital outpatient department provide a safe, cost-effective alternative with significant cost savings to the healthcare system. Advancements in technology and perioperative management strategies have expanded the number of eligible patients to optimize outcomes with a focus on safety. Therefore, this review will describe the safety, efficacy, economics, and perioperative protocols for performing UKA in an outpatient setting. Patient selection, risk factors, patient education and expectations, anesthesia, pain management strategies, and outcomes will be discussed.

Fixed-bearing medial unicompartmental knee arthroplasty: New indications in the anterior cruciate ligament-deficient knee

The anterior cruciate ligament (ACL)-deficient osteoarthritic knee presents a challenging disease entity, which requires careful thought to restore function and enable return to activities. Advancements in technology and surgical techniques have expanded indications for unicompartmental knee arthroplasty (UKA), to inlcude ACL-deficiency in appropriately-selected patients. An improved understanding of the ACL-deficient osteoarthritic knee can aid in clinical and surgeon decision-making to restore knee function. This review will discuss current practice guidelines for the ACL-deficient knee with single-compartment osteoarthritis, including pathoanatomy, indications, contraindications, technical considerations, and clinical outcomes.

The efficacy of unicondylar knee arthroplasty for medial compartment arthritis of the knee combined with anterior cruciate ligament dysfunction

BACKGROUND

To investigate the outcome and prognosis after Unicondylar knee arthroplasty (UKA) in patients with medial compartment arthritis of the knee combined with anterior cruciate ligament(ACL) dysfunction.

METHODS

A total of 122 patients diagnosed with knee osteoarthritis and treated with medial mobile platform unicondylar replacement at our center from January 2019 to December 2021 were retrospectively included in the study, and were divided into two groups according to ACL function, namely the normal ACL function group (ACLF) and the poor ACL function (N-ACLF) group. The postoperative results and prognosis of the two groups were evaluated and compared.

RESULTS

This study included 122 patients who underwent UKA surgery. There were no statistical differences in preoperative and postoperative posterior tibial tilt angle, knee mobility, KOOS, and prognosis between the two groups (P > 0.05).

CONCLUSION

For medial compartment arthritis of the knee combined with ACL malfunction, surgery resulted in pain relief, improved quality of life and a good prognosis for such patients. It is hoped that clinicians will perform UKA in patients with ACL dysfunction after a comprehensive evaluation to improve their quality of life.

Establishing patient-centered metrics for the knee injury and osteoarthritis outcome score following medial unicompartmental knee arthropalsty

BACKGROUND

This study aimed to determine the minimal clinically important difference (MCID) and the patient acceptable symptoms state (PASS) threshold for the knee injury and osteoarthritis outcome score (KOOS) pain subscore, KOOS physical short form (PS), and KOOS joint replacement (JR) following medial unicompartmental knee arthroplasty (mUKA).

METHODS

Prospectively collected data from 743 patients undergoing mUKA from a single academic institution from April 2015 through March 2020 were analyzed. Patient-reported outcome measures (PROMs) were collected both pre-operatively and 1-year post-operatively. Distribution-based and anchored-based approaches were used to estimate MCIDs and PASS, respectively. The optimal cut-off point and the percentage of patients who achieved PASS were also calculated.

RESULTS

MCID for KOOS-pain, KOOS-PS, and KOOS-JR following mUKA were calculated to be 7.6, 7.3, and 6.2, respectively. The PASS threshold for KOOS pain, PS, and JR were 77.8, 70.3, and 70.7, with 68%, 66%, and 64% of patients achieving satisfactory outcomes, respectively. Cut-off values for delta KOOS pain, PS, and JR were found to be 25.7, 14.3, and 20.7 with 73%, 69%, and 68% of patients achieving satisfactory outcomes, respectively.

CONCLUSION

The current study identified useful values for the MCID and PASS thresholds at 1 year following medial UKA of KOOS pain, KOOS PS, and KOOS JR scores. These values may be used as targets for surgeons when evaluating PROMS using KOOS to determine whether patients have achieved successful outcomes after their surgical intervention. Potential uses include the integration of these values into predictive models to enhance shared decision-making and guide more informed decisions to optimize patient outcomes.

LEVEL OF EVIDENCE

III.

The Role of Severe Lateral Facet Patellar Osteoarthritis in Patient Selection for Success of a Medial Unicompartmental Knee Arthroplasty: Mean Follow-Up of 10 Years

BACKGROUND

Lateral facet patellar osteoarthritis (LFPOA) has been reported as a contraindication for medial unicompartmental (UKA). The purpose of this paper was to determine if severe LFPOA was related to lower survivorship and patient-reported outcomes following medial UKA.

METHODS

A total of 170 medial UKAs were performed. Severe LFPOA was defined as Outerbridge grade 3 to 4 damage on the lateral facet cartilage surfaces of the patella as noted intraoperatively. There were 122 of 170 patients (72%) who had noLFPOA and 48 of 170 patients (28%) who had had severe LFPOA. A routine patelloplasty was performed in all patients. Patients completed the Veterans RAND 12-Item Health Survey (VR-12) Mental Component Score (MCS) and Physical Component Score (PCS), Knee Injury and Osteoarthritis Outcome Score (KOOS), and Knee Society Score.

RESULTS

There were 4 patients in the noLFPOA group who required total knee arthroplasty and 2 in the LFPOA group. There was no significant difference in mean survival time: noLFPOA = 17.2 years [95% confidence interval (CI): 17 to 18] and LFPOA = 18.0 years [95% CI: 17 to 19] (P = .94). At mean follow-up of 10 years, there were no significant differences in knee flexion or extension. Patello-femoral crepitus without pain was noted in 7 patients who had LFPOA and 21 patients who had noLFPOA. There were no significant differences in VR-12 MCS, PCS, KOOS subscales, or Knee Society Score between groups. Patient acceptable symptom state (PASS) was achieved in 80% (90 of 112) for KOOS ADL in the noLFPOA group and 82% (36 of 44) in the LFPOA group (P = .68). PASS was achieved in 82% (92 of 112) for KOOS Sport in the noLFPOA group and 82% (36/44) in the LFPOA group (P = .87).

CONCLUSION

At a mean of 10 years, patients who had LFPOA had equivalent survivorship and functional outcomes to patients who did not have LFPOA. These long-term results suggest that asymptomatic grade 3 or 4 LFPOA is not a contraindication to medial UKA.

Isolated Lateral Tibiofemoral Compartment Osteoarthritis: Survivorship and Patient Acceptable Symptom State After Lateral Fixed-Bearing Unicompartmental Knee Arthroplasty at Mean 10-Year Follow-up

BACKGROUND

Lateral unicompartmental knee arthroplasty (UKA) is an excellent option to alleviate disability and restore function in patients with lateral compartment knee osteoarthritis (OA). The purpose of the present study was to determine the survivorship and long-term outcomes in both younger/middle-aged and older patients with lateral compartment OA following non-robotically-assisted, fixed-bearing lateral UKA and to determine if an acceptable symptom state can be achieved.

METHODS

All patients were managed with fixed-bearing lateral UKA by a single surgeon utilizing a lateral parapatellar approach without robotic assistance. The primary outcome variables were the Knee injury and Osteoarthritis Outcome Score (KOOS) Activities of Daily Living (ADL) and Sport subscale scores. In addition, the other KOOS subscores, the Lysholm score, the achievement of the Patient Acceptable Symptom State (PASS), and the Veterans RAND (VR-12) Physical Component Summary score (PCS) and Mental Component Summary score (MCS) were collected. Failure was defined as conversion to total knee arthroplasty (TKA). Patients were divided into 2 cohorts: younger/middle-aged patients (<60 years of age) and older patients (≥60 years of age).

RESULTS

A cohort of 256 patients underwent medial (n = 193) or lateral (n = 63) UKA. Sixty-one patients met the inclusion criteria. At mean of 10 years (range, 4 to 17 years) of follow-up, there were no significant differences between the groups in terms of any patient-reported outcome measures (p > 0.05). The percentage of patients in whom PASS was achieved on the KOOS ADL and Sport subscores was 82% and 88%, respectively, in the younger cohort and 80% and 80%, respectively, in the older cohort. The mean survival estimate of the prothesis was 15.3 years (95% confidence interval [CI], 14.5 to 16.2 years) for the entire cohort. The estimated rate of implant survival in the younger cohort was 100% at 5 and 10 years, and the estimated rate of implant survival in the older cohort was 98% at 5 years and 96% at 10 years.

CONCLUSIONS

Lateral fixed-bearing, non-robotic UKA for the treatment of isolated lateral compartment OA resulted in >80% of patients reaching an acceptable symptom state in terms of both activities of daily living and sporting activities. UKA provides an excellent option that provides longevity with high PASS rates and return to activities with a low risk of complications and failure.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Anterior cruciate ligament deficiency versus intactness for outcomes in patients after unicompartmental knee arthroplasty: a systematic review and meta-analysis

Objective: The unicondylar knee arthroplasty (UKA) procedure is primarily indicated for osteoarthritis of the knee. Anterior cruciate ligament (ACL) defects have long been considered a contraindication to UKA. However, recent clinical studies have found that ACL defects do not affect postoperative outcomes in UKA. To elucidate whether ACL defects affect postoperative outcomes in UKA, we performed a systematic review and Meta-analysis of observational cohort studies comparing the effects of ACL defects and intactness on surgical outcomes in UKA.

Methods: In this study, we used “Anterior Cruciate Ligament”, “Anterior Cruciate Ligament Injuries” and “Arthroplasty, Replacement, Knee” as the subject terms according to PICOS principles. These subject terms and the corresponding free texts were used to conduct a systematic search in the three major databases PubMed, Embase and Cochrane on December 9, 2021. The main study variables included age, gender, region, definition of ACL defect and diagnosed diseases. The study used a random effect model to pool the effect of 95% CIs. To explore the sources of heterogeneity and to test the stability of the results, a sensitivity analysis was performed.

Results: The systematic review found no significant differences in postoperative clinical outcomes in the elderly population when unicondylar replacement was performed in the setting of multiple factors such as injury, defects, longitudinal tear, and synovial bursa injury defined as ACL deficiency. The primary clinical outcomes included postoperative revision, Tegner activity score, and Oxford Knee Score (OKS). After statistical meta-analysis, postoperative outcomes such as postoperative revision (OR, 1.174; 95% CIs, 0.758–1.817) and Tegner activity score (OR, -0.084; 95% CIs, -0.320–0.151) were not statistically different.

Conclusion: There was no difference in postoperative revision rates and functional outcomes such as Tegner activity score between the ACL-deficient group compared with the ACL-intact group. For the present results, it is not advisable to consider ACL deficiency as a contraindication of UKA.