Robotic-assisted unicompartmental knee arthroplasty improves functional outcomes, complications, and revisions

Aims

Robotic-assisted unicompartmental knee arthroplasty (R-UKA) has been proposed as an approach to improve the results of the conventional manual UKA (C-UKA). The aim of this meta-analysis was to analyze the studies comparing R-UKA and C-UKA in terms of clinical outcomes, radiological results, operating time, complications, and revisions.

Methods

The literature search was conducted on three databases (PubMed, Cochrane, and Web of Science) on 20 February 2024 according to the guidelines for Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). Inclusion criteria were comparative studies, written in the English language, with no time limitations, on the comparison of R-UKA and C-UKA. The quality of each article was assessed using the Downs and Black Checklist for Measuring Quality.

Results

Among the 3,669 articles retrieved, 21 studies on 19 series of patients were included. A total of 3,074 patients (59.5% female and 40.5% male; mean age 65.2 years (SD 3.9); mean BMI 27.4 kg/m2 (SD 2.2)) were analyzed. R-UKA obtained a superior Knee Society Score improvement compared to C-UKA (mean difference (MD) 4.9; p < 0.001) and better Forgotten Joint Score postoperative values (MD 5.5; p = 0.032). The analysis of radiological outcomes did not find a statistically significant difference between the two approaches. R-UKA showed longer operating time (MD 15.6; p < 0.001), but reduced complication and revision rates compared to C-UKA (5.2% vs 10.1% and 4.1% vs 7.2%, respectively).

Conclusion

This meta-analysis showed that the robotic approach for UKA provided a significant improvement in functional outcomes compared to the conventional manual technique. R-UKA showed similar radiological results and longer operating time, but reduced complication and revision rates compared to C-UKA. Overall, R-UKA seems to provide relevant benefits over C-UKA in the management of patients undergoing UKA.

Malposition is main cause of failure of Oxford mobile-bearing medial unicompartmental knee arthroplasty

Aims

Unicompartmental knee arthroplasty (UKA) is the preferred treatment for anterior medial knee osteoarthritis (OA) owing to the rapid postoperative recovery. However, the risk factors for UKA failure remain controversial.

Methods

The clinical data of Oxford mobile-bearing UKAs performed between 2011 and 2017 with a minimum follow-up of five years were retrospectively analyzed. Demographic, surgical, and follow-up data were collected. The Cox proportional hazards model was used to identify the risk factors that contribute to UKA failure. Kaplan-Meier survival was used to compare the effect of the prosthesis position on UKA survival.

Results

A total of 407 patients who underwent UKA were included in the study. The mean age of patients was 61.8 years, and the mean follow-up period of the patients was 91.7 months. The mean Knee Society Score (KSS) preoperatively and at the last follow-up were 64.2 and 89.7, respectively (p = 0.001). Overall, 28 patients (6.9%) with UKA underwent revision due to prosthesis loosening (16 patients), dislocation (eight patients), and persistent pain (four patients). Cox proportional hazards model analysis identified malposition of the prostheses as a high-risk factor for UKA failure (p = 0.007). Kaplan-Meier analysis revealed that the five-year survival rate of the group with malposition was 85.1%, which was significantly lower than that of the group with normal position (96.2%; p < 0.001).

Conclusion

UKA constitutes an effective method for treating anteromedial knee OA, with an excellent five-year survival rate. Aseptic loosening caused by prosthesis malposition was identified as the main cause of UKA failure. Surgeons should pay close attention to prevent the potential occurrence of this problem.

Early- to Mid-Term Review of a Prospective, Multi-Center, International, Outcomes Study of an Anatomically Designed Implant with Posterior-Stabilized Bearing in Total Knee Arthroplasty

Background and Objectives: National joint registries report higher total knee arthroplasty (TKA) revision rates in posterior-stabilized (PS) systems compared to non-posterior-stabilized designs. The purpose of this study was to investigate the implant survivorship and clinical outcomes of an anatomic implant with a PS bearing. Materials and Methods: An early- to mid-term follow-up of a prospective, multi-center, non-controlled outcomes study of patients who received primary TKA between November 2014 and June 2017 was performed. A total of 800 cases using PS bearings that were implanted in 664 patients were monitored post-operatively for their implant survivorship and adverse events for up to five years. The Knee Society Knee and Function scores, patient satisfaction, the five-dimensional European Quality of Life questionnaire, and range of motion (ROM) were evaluated pre-operatively and post-operatively at six weeks, six months, one year, two years, three years, and five years. Results: The mean follow-up period was 3.7 ± 1.3 years, and the three-year implant survival rate was 99.3% (95% CI: 98.4%, 99.7%) with five revisions during the five-year follow-up. Patient satisfaction was 96.1% at six weeks and increased to 99.3% at one year. All patient-reported outcome measures significantly (p < 0.0001) increased up to the one-year follow-up and then remained stable up to the five-year follow-up. Conclusions: This study supports the excellent survivorship and patient-reported outcomes of the Persona® Knee system using cemented, fixed bearing, posterior-stabilized components with minimal complications at early- to mid-term follow-up in an international Asian population. Ongoing observations are being performed to investigate the mid- to long-term survivorship and clinical outcomes associated with this knee system.

Midvastus Versus Medial Parapatellar Approach in Simultaneous Bilateral Total Knee Arthroplasty

BACKGROUND

The purpose of this study was to compare the postoperative outcomes over a period of 3 years in patients who underwent bilateral total knee arthroplasty (TKA) using midvastus (MV) versus medial parapatellar (MPP) approaches.

METHODS

In this retrospective study, 2 propensity-matched cohorts of patients who underwent simultaneous bilateral TKA via MV (n = 100) and MPP (n = 100) approaches from January 2017 to December 2018 were compared. Surgical parameters compared were surgery time and the incidence of lateral retinacular release (LRR). Clinical parameters including the visual analog score for pain, time for straight leg raise (SLR), range of motion, the Knee Society Score, and the Feller patellar score were assessed in the early postoperative and follow-up periods up to 3 years. Radiographs were evaluated for alignment, patellar tilt, and displacement.

RESULTS

LRR was performed on 17 knees (8.5%) in the MPP group and 4 knees (2%) in the MV group which was significant (P = .03). The time to SLR was significantly lower in the MV group. There was no statistically significant difference in the length of hospital stay between the groups. The visual analog score, range of motion, and Knee Society Score were better in the MV group within 1 month (P < .05), but no statistically significant differences were found later. Patellar scores, radiographic patellar tilt, and displacements were similar at all follow-up periods.

CONCLUSION

In our study, the MV approach had faster SLR, less LRR, and better pain and function scores in the first few weeks after TKA. However, its effect on different patient outcomes has not been sustained at 1 month and further follow-up points. We recommend that surgeons use the surgical approach with which they are most familiar.

Improved Knee Function with Customized vs. Off-the-Shelf TKA Implants-Results of a Single-Surgeon, Single-Center, Single-Blinded Study

BACKGROUND

Recent studies have been able to show certain benefits of Customized, Individually Made (CIM) compared to Off-the-Shelf (OTS) total knee arthroplasties (TKAs), but evidence is still lacking regarding the benefits of these implant systems. This study aimed to find differences in scores and functional outcome by comparing CIM and OTS implants, using Patient-Reported Outcome Measures (PROMs) and functional tests for activities of daily living in a single-surgeon setup.

METHODS

A total of 48 patients (16 CIM vs. 32 OTS) were consecutively enrolled and blindly examined. Functional testing was performed using four timed functional tests (TUG, WALK, TUDS, and BBS) and the VAS for pain. The Aggregated Locomotor Function (ALF) score was then calculated based on the addition of the average times of the three functional tests.

RESULTS

The CIM group showed significantly faster times in all functional tests and significantly better ALF scores. There were remarkable differences in the assessment of maximum pain sensation between the two groups, with superiority in the CIM group. The PROMs analysis revealed a higher proportion of excellent and good ratings for the items objective and function (KSS) in the CIM group.

CONCLUSION

The study showed that time-limited activities of daily living (ADLs) can be completed significantly faster with a CIM prosthesis and that a significantly higher percentage in this group reports freedom from pain during certain loads. Partial aspects of the PROM scores are also better in this group; however, this superiority could not be shown with regard to most PROM scores collected in this study.

Bridge Plating Versus Hybrid External Fixation in the Management of Proximal Tibia Metaphyseal Fractures

BACKGROUND

Due to the surge in high-speed road traffic accidents during the past few years, extra-articular proximal tibia fractures have also risen in number. For the treatment of such fractures, various options are available like conservative treatment with casting, surgical treatment with plate osteosynthesis, or a hybrid external fixator. Exposure of the bone surface and extensive soft tissue dissection is needed in bridge plating, posing a risk of bleeding, infection, and soft-tissue healing issues, and the blood supply of the fractured area is also hampered as the periosteum is also destroyed. To avoid these complications, a hybrid external fixator can be used but it has its own risks of malunion, non-union, and pin-tract infections; another drawback is patient compliance. In this study, we compare the clinical and functional outcomes of two treatment modalities, i.e., bridge plating and hybrid external fixator, in the treatment of proximal tibia metaphyseal fractures.

MATERIALS AND METHODS

This prospective randomized study was conducted from February 2021 to June 2022 on 46 adult patients diagnosed with proximal tibia metaphyseal fracture and willing to participate. An odd number of patients were treated with a bridge plate and even with a hybrid external fixator.

RESULTS

A total of 46 patients were included in the study, sustaining proximal tibia metaphyseal fracture, out of which 23 patients underwent hybrid external fixation with an outcome of 69.43 ± 8.11 according to the Knee Society Score (KSS) and 23 for bridge plating which showed better results as their score at final follow-up was 75.00 ± 8.22.

CONCLUSION

According to our study, we found that bridge plating is a better treatment modality than the hybrid external fixator as the former showed better postoperative knee range of motion and functional outcome and led to a smaller number of complications. But the clinical outcome would also be influenced by the type of fracture, degree of comminution, type of injury, i.e., open or closed, and quality of bone.

Use of an Intramedullary Allogenic Fibular Strut Bone and Lateral Locking Plate for Distal Femoral Fracture with Supracondylar Comminution in Patients over 50 Years of Age

Background and Objectives: Distal femoral fracture is a severe injury that makes surgery challenging, particularly comminuted fractures in the supracondylar region. This study aimed to evaluate the outcomes of distal femoral fracture treated with the application of an intramedullary fibular allogenic bone strut in open reduction and internal fixation (ORIF) with precontoured locking plates in patients over 50 years of age. Materials and Methods: The study retrospectively enrolled 202 patients over 50 years of age with traumatic comminuted distal femoral fracture (AO/OTA 33-A3, 33-C2 and 33-C3) treated with ORIF with a locking plate from January 2016 to December 2019. The two groups were divided into patients who received an intramedullary allogenic bone strut and those who did not. Patients were followed for at least 1 year, with their function scores and radiographic data recorded. Results: A total of 124 patients were recruited, comprising 60 men and 64 women with an average age of 62.4 ± 8.5 years. The 36 patients who had received an intramedullary allogenic fibular bone strut reported lower postoperative pain scores at 1 month and lower postoperative Knee Society Scores (KSS) at 3 months than the control group. The application of an intramedullary allogenic fibular bone strut appeared to be significantly correlated with better 3-month postoperative KSS. Conclusions: The ORIF of distal femoral comminuted fracture with an intramedullary allogenic fibular bone strut can reduce pain and improve knee function in the early stages of postoperative rehabilitation and may reduce the time to union in patients over 50 years of age.

Clinical Outcomes Following Distal Femur Replacement for Periprosthetic Distal Femur Fractures: A Systematic Review and Meta-Analysis

BACKGROUND

Management of periprosthetic distal femur fractures (PDFFs) is often complicated by poor bone quality and limited bone stock making fixation attempts challenging and prone to failure. Distal femoral replacement (DFR) is being used to treat such injuries although outcome data are mostly from small case series. We sought to systematically review the literature on DFR for PDFF to summarize their outcomes.

METHODS

PubMed, MEDLINE (EBSCO), and Cochrane Central Database were searched to identify reports of PDFFs treated with DFR. Articles reporting on 5 or more knees were systematically reviewed for clinical function, complications, and mortality. Random effects meta-analysis was used to create summary estimates and publication bias also assessed.

RESULTS

Of 287 identified and screened articles, 15 were included, 14 retrospective, reporting on 352 knees. Following DFR, 87% (95% confidence interval [CI] 71-95) of patients were able to ambulate. The mean postoperative Knee Society Score was 80 (95% CI 77-84). The risk of periprosthetic joint infection was 4.3% (95% CI 2.2-8.2). One-year postoperative mortality rate was 10% (95% CI 6-18). There was some evidence of publication bias with a trend toward smaller studies reporting lower infection risk and mortality.

CONCLUSION

DFR for PDFFs is associated with high functional outcomes and a relatively modest risk of infection. The periprosthetic joint infection and 1-year mortality rates reported here should be considered lower bounds estimates due to publication bias and loss to follow-up. Further investigation of long-term outcomes following DFR for PDFFs is warranted though short-term functional outcomes are promising.

Improved Range of Motion and Patient-Reported Outcome Scores With Fixed-Bearing Revision Total Knee Arthroplasty for Suboptimal Axial Implant Rotation

BACKGROUND

Suboptimal implant rotation has consequences with respect to knee kinematics and clinical outcomes. We evaluated the functional outcomes of revision total knee arthroplasty (TKA) for poor axial implant rotation.

METHODS

We retrospectively reviewed 42 TKAs undergoing aseptic revision for poor axial implant rotation. We assessed improvements in Knee Society Score (KSS) and final range of motion (ROM). Subgroup analyses were performed for preoperative instability and stiffness, as well as the number of components revised and level of implant constraint used.

RESULTS

Revision for poor axial rotation in isolation improved KSS from 52 ± 22 to 84 ± 25 (P < .001), and flexion increased from 105 ± 21° to 115 ± 13° (P = .001). Revision in the setting of instability significantly improved the KSS (P < .001) but did not affect ROM (P = .172). Revision in the setting of stiffness significantly improved both KSS (P < .001) and ROM (P = .002). There was no statistically significant difference between the postoperative KSS (P = .889) and final knee flexion (P = .629) with single- or both-component revision TKA for isolated poor axial rotation or between the postoperative KSS (P = .956) and final knee flexion (P = .541) with or without the use of higher constraint during revision TKA for isolated poor axial rotation.

CONCLUSION

Revision TKA for poor axial alignment improves clinical outcomes scores and functional ROM.

Crosscultural Adaptation and Validation of the Korean Version of the New Knee Society Knee Scoring System

BACKGROUND

The 2011 Knee Society Score^© (2011 KS Score^©) is used to characterize the expectations, symptoms, physical activity, and satisfaction of patients who undergo TKA and is widely used to assess the outcome of TKA. However, it has not been adapted or validated for use in Korea.

QUESTIONS/PURPOSES

We developed a Korean version of the 2011 KS Score and evaluated the (1) test-retest reliability, (2) convergent validity, and (3) responsiveness of the Korean version.

METHODS

The Korean version of the 2011 KS Score was derived by using a well-established translational procedure based on international guidelines, which include translation, synthesis, back-translation, expert committee review, pretesting, and submission for appraisal. A total of 123 patients with knee osteoarthritis who were scheduled to undergo TKA were recruited for the study. Ninety percent of the patients (111 of 123) were women, which is an exact representation of the Korean population having TKAs. To evaluate reliability, the patients were evaluated twice during a 4-week interval using the questionnaire. Reliability was assessed by using intraclass correlation coefficients (ICCs) and internal consistency by using Cronbach's alpha to determine the validity of the Korean version of the 2011 KS Score. The patients were evaluated by using the validated Korean versions of the WOMAC and SF-36 questionnaires. Spearman's correlation coefficient was used for validation. Responsiveness was determined by calculating the standardized response mean from the preoperative and postoperative test scores in the Korean version of the 2011 KS Score. To address the gender disparity in our study we identified 53 males who underwent TKA for osteoarthritis after completion of this study and generated age-matched controlled groups to evaluate construct validity and responsiveness in Korean males.

RESULTS

The reliability proved good to excellent with an ICC between 0.69 and 0.85, depending on the clinical properties tested, which included the following: symptoms, satisfaction, expectation, and total functional activity consisting of functional activity, standard activity, advanced activity, and discretionary activity. All subscales showed good to excellent internal consistency indicated by Chronbach's alpha (range, 0.83-0.92). For validity, three of the four domains (the exception was expectation) of the 2011 KS Score, correlated either strongly or moderately with the Korean WOMAC score (r ≥ 0.35). When compared with the SF-36, the satisfaction domain showed a weak positive correlation with all the subscales of the SF-36 except general health (r < 0.35). The activity domain showed a strong positive correlation with physical function (r = 0.62) and physical component summary (r = 0.52), moderate with physical role (r = 0.46), and weak with bodily pain (r = 0.26) and social function (r = 0.31). The symptom domain also exhibited a similar moderate positive correlation with physical function (r = 0.41) and weak positive correlation with bodily pain, social function, and physical component summary (r = 0.22, 0.20, and 0.26, respectively). For responsiveness, all the domains of Korean version of the 2011 KS Score, except for expectation, showed large changes (> 0.8), calculated as standardized response mean. The total amount of the Korean version of the 2011 KS Score (2.03, p < 0.001) showed higher responsiveness when compared with the WOMAC total (1.88, p < 0.001) and SF-36 physical and mental component summaries (1.14, p < 0.001; and 0.68, p < 0.001, respectively).

CONCLUSIONS

The Korean version of the 2011 KS Score was successfully developed using a process of crosscultural adaptation for the Korean-speaking population who had undergone TKA for osteoarthritis of the knee. The Korean version of the 2011 KS Score was shown to be a reliable, valid, and responsive tool and can be used to assess functional outcomes and expectations of Korean patients who undergo TKA. The demographic features of TKA in the Korean population should be taken into account with additional studies recommended to further investigate these psychometric properties in Korean men.

LEVEL OF EVIDENCE

Level II, diagnostic study.

Increased Risk of Revision, Reoperation, and Implant Constraint in TKA After Multiligament Knee Surgery

BACKGROUND

The risk of major complications and revision arthroplasty after TKA in patients who previously underwent multiligament knee surgery have been poorly characterized.

QUESTIONS/PURPOSES

Is multiligament knee surgery before TKA associated with (1) worse implant survival, (2) increased use of TKA design constraint, (3) a greater risk for major complications, and (4) poorer scores for pain and function compared with similar patients receiving TKA for primary osteoarthritis?

METHODS

Fifty-nine TKAs were performed at our institution between 1985 and 2014 in 59 patients (36 men, 23 women; mean age, 53 years) with a history of previous multiligament knee surgery (≥ two ligaments). Of those, we had followup for 39 (66%), 18 (31%), and six (10%) patients at 5, 10, and 15 years, respectively; mean followup was 5.4 years (range, 1-25 years). A two-to-one matched control group consisting of patients undergoing primary TKA for the diagnosis of osteoarthritis was selected for comparison. Patients were matched based on gender, age at primary TKA (within 5 years), and date of the TKA (within 5 years). Medical records were reviewed for survivorship, TKA design, complications (reoperation, revision, infection, manipulation under anesthesia, and periprosthetic joint infection), TKA design, and clinical outcomes (Knee Society Scores [KSS], Knee Society Function Score [KSS-F]).

RESULTS

The overall 15-year revision-free survival in patients with prior multiligament knee surgery was decreased in comparison to the matched controls (42% [95% CI, 16%-73%] vs 94% [95% CI, 81%-99%]; p < 0.001). Varus-valgus constraint implant design was used for more patients in the multiligament cohort at index TKA than in the matched control group (9/59 [15%] vs 0/110 [0%], respectively; odds ratio [OR], 45; 95% CI, 3-781; p = 0.009). Patients with a history of multiligament knee surgery also were at increased risk of reoperation for any cause (14/59 [24%] vs 7/118 [6%]; OR, 5; 95% CI, 2-14; p = 0.001). With the numbers available, there was no difference in the frequency of manipulation under anesthesia after TKA (10% [6/59] versus 3% [4/118]; p = 0.08) A higher proportion of patients in the multiligament cohort had infections develop compared with the matched controls (4/59 [7%] vs 1/118 [< 1%)], respectively; p = 0.04). There was no difference in the KSS improvement after TKA between the multiligament group and the control group (34 ± 18 vs 28 ± 15; p = 0.088). The final KSS and KSS-F scores likewise showed no difference between those groups (88 ± 13 vs 85 ± 10; p = 0.232) (85 ± 17 vs 84 ± 14; p = 0.75).

CONCLUSIONS

A history of multiligament surgery is associated with lower long-term survivorship, higher use of constrained TKA designs, and higher risk of major complications, including reoperation and infection. Further research is necessary to determine if a particular multiligamentous surgical technique can prevent posttraumatic arthritis and TKA complications.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Diabetes is a Risk Factor for Restricted Range of Motion and Poor Clinical Outcome After Total Knee Arthroplasty

BACKGROUND

We investigated the effects of diabetes mellitus on knee range of motion, muscle strength, and functional outcome after total knee arthroplasty.

METHODS

A total of 20 patients with type 2 diabetes and 20 patients without diabetes matched for age, body mass index, knee range of motion, and muscle strength at baseline participated in this study. We examined knee range of motion and muscle strength and assessed functional activities using the new Knee Society Score questionnaire for each patient 1 month preoperatively and at 6 and 12 months postoperatively.

RESULTS

Patients with diabetes had significantly lower knee flexion and smaller improvements in the new Knee Society Score than patients without diabetes.

CONCLUSION

Our results suggest that clinicians should treat and monitor patients with diabetes closely to prevent restricted knee range of motion and poorer functional recovery after total knee arthroplasty.