Restricted kinematic alignment in primary total knee arthroplasty: A systematic review of radiographic and clinical data

Mechanical versus kinematic alignment for total knee arthroplasty: a meta-analysis

INTRODUCTION

The present meta-analysis compared mechanical versus kinematic alignment in total knee arthroplasty (TKA). The outcomes of interest were patient-reported outcome measures (PROMs), range of motion (ROM), and revision rate.

METHODS

This study was conducted according to the 2020 PRISMA statement. In July 2024, PubMed, Web of Science, Google Scholar, and Embase were accessed without time constraints. All the clinical studies that compared mechanical versus kinematic alignment in total knee arthroplasty were accessed.

RESULTS

30 studies (3133 TKAs) were collected. The mean duration of the follow-up was 30.8 ± 38 months. No difference was found in Knee KSS-F, Knee Society Score (KSS, P = 0.2) and its function subscale (P = 0.3), visual analogue scale (VAS, P = 0.3), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC, P = 0.2), Oxford Knee Score (OKS, P = 0.5). No difference was found in the rate of revision (P = 0.4). The ROM was slightly greater in the kinematic group (P < 0.0001).

CONCLUSION

PROMs and revision did not show a difference between mechanical and kinematic alignment in TKA. However, a minimal difference in the ROM was evidenced, which probably does not have clinical relevance.

LEVEL OF EVIDENCE

Level IV, systematic review and meta-analysis.

The Orientation of the Prosthetic Trochlear Angle Is Predictable in Kinematically Aligned Total Knee Arthroplasty

Objective: This study aimed to predict the orientation of the prosthetic trochlear angle (PTA) relative to the quadriceps line of force (QLF) in kinematically aligned total knee arthroplasty (KA-TKA) by using preoperative radiographic parameters. Methods: This study included 144 patients who underwent KA-TKA with a femoral component designed for mechanical alignment (MADFC), with a PTA of 6°. Radiographic parameters, including the lateral distal femoral angle (LDFA) and the QLF^FMA (quadriceps line of force-femoral mechanical axis angle), were measured pre- and postoperatively. We developed and validated a formula to predict PTA orientation based on these values: "X = QLF^FMA-(PTA-(90°-LDFA))", where values of x > 0° predict a lateral PTA orientation, while x < 0° predicts a medial PTA. Results: The formula accurately predicted PTA orientation in 100% of the cases, with a difference between the predicted and actual PTA values of <0.5° in 75% of the cases. Patients with an LDFA < 86° and lower QLF^FMA values were identified as at risk for medial PTA orientation, which can affect patellar tracking. Conclusions: Our formula offers a reliable preoperative tool for predicting PTA orientation in KA-TKA, aiding in component selection and alignment strategies to improve patellofemoral function and patient outcomes.

Novel technique for achieving the under-correction of native tibial varus in calipered restricted kinematically aligned total knee arthroplasty - A validation study

PURPOSE

Restricted kinematic alignment (rKA) TKA is relatively newer technique for achieving an overall under-corrected limb alignment. The present study aims to provide an easy and reproducible technique for achieving calipered rKA-TKA (crKA-TKA) using routine instrumentation.

METHOD

A prospective study was conducted including 30 patients (30 knees). All patients underwent crKA-TKA by the same surgeon. Pre-operatively all patients underwent long film standing radiographs, and coronal angles were measured to plan tibial bony cuts and the femoral axis angle (FAA) to restore tibial varus under correction and native distal femoral anatomy, respectively. Intra-operatively while taking tibial cuts, the alignment rod was noted to be always pointing towards the "third metatarsal" of the ipsilateral foot.

RESULTS

30 patients underwent total knee replacement with crKA technique. Angular corrections were satisfactory with all patients reaching the target MPTA of 87.48 ± 0.78 and LDFA of 90.301 ± 2.66 as planned, with an overall under-corrected limb alignment. HKA was achieved within a target of < ± 3 degrees of the native knee (3.56 ± 1.29). Post-operative radiological parameters were checked by two separate observers with excellent intra-class correlation coefficients.

CONCLUSION

The present study validates a novel intra-operative technique of confirming an under-corrected native tibial varus while performing crKA-TKA. The radiological outcomes of the study confirm that with careful pre-operative planning, coronal angular targets were easily achievable with very less outliers. Study further establishes that this method of calipered technique in rKA-TKA using routine digital templating software and standard instrumentations is an alternative method of executing rKA.

LEVEL OF EVIDENCE

IV, Prospective case series.

Boundaries in Kinematic Alignment: Why, When, and How

The use of alternative alignments in total knee arthroplasty (TKA) has recently been increasing in popularity: many of these alignments have been included in the broad spectrum of "kinematic alignment." This alternative approach was recommended to increase patients' satisfaction since many studies based on patient-reported outcome measures (PROMs) showed that every fifth patient is not satisfied with the surgical outcome. In fact, the original kinematic alignment technique was designed as a "pure resurfacing" technique, maintaining the preoperative axes (flexion-extension and axial rotation) of the knee. In adjunct, many new classifications of the preoperative limb deformity have been proposed to include a large range of knee anatomies, few of them very atypical. Following those classifications, many surgeons aimed for a reproduction of unusual anatomies putting in jeopardy the survivorship of the implant according to the classical "dogma" of a poor knee kinematics and TKA biomechanics if the final hip-knee-ankle (HKA) axis was not kept within 5 degrees from neutral. This article reviews the literature supporting the choice of setting alignment boundaries in TKA when surgeons are interested in reproducing the constitutional knee anatomy of the patient within a safe range.

Variability in Alignment and Bone Resections in Robotically Balanced Total Knee Arthroplasties

Image-based robotic-assisted total knee arthroplasty (RA-TKA) allows three-dimensional surgical planning informed by osseous anatomy, with intraoperative adjustment based on a dynamic assessment of ligament laxity and gap balance. The aim of this study was to identify ranges of implant alignment and bone resections with RA-TKA. We retrospectively reviewed 484 primary RA-TKA cases, stratified by preoperative coronal alignment. Demographics and intraoperative data were collected and compared using Chi-square and ANOVA tests. Planned limb, femoral, and tibial alignment became increasingly varus in a progressive order from valgus to neutral to the highest in varus knees (p < 0.001). Planned external transverse rotation relative to the TEA was lowest in the valgus cohort; relative to the PCA, whereas the varus cohort was highest (p < 0.001, both). Planned resections of the lateral distal femur and of the medial posterior femur were greater in the varus group compared to neutral and valgus (p < 0.001). There were significant differences between cohorts in planned tibia resections, laterally and medially. Varus knees demonstrated higher variability, while valgus and neutral had more metrics with low variability. This study demonstrated trends in intraoperative planned alignment and resection metrics across various preoperative coronal knee alignments. These findings contribute to the understanding of RA-TKA and may inform surgical decision-making.

Comparison of short-term clinical results between modified kinematically-aligned and guided motion bicruciate stabilized total knee arthroplasty

BACKGROUND

Both kinematically-aligned (KA) total knee arthroplasty (TKA) and bicruciate stabilized (BCS) TKA aim to reproduce the physiological knee kinematics. In this study, we compared the femoro-tibial component rotational mismatch between patients who underwent modified KA-TKA and those who received guided-motion BCS-TKA, and its influence on the clinical outcomes.

METHODS

In this retrospective study, 77 consecutive patients were included and divided into two groups: subjects who underwent modified KA-TKA with Persona (KA Group; n = 42) and those who received BCS-TKA with JOURNEY II (BCS group; n = 35). Range of motion, the 2011 Knee Society Score (KSS), the rotational alignment of the femoral and tibial components, and the correlations between the rotational mismatch and the 2011 KSS subscales were examined.

RESULTS

The postoperative objective knee indicators (P = 0.0157), patient satisfaction (P = 0.0039) and functional activity scores (P = 0.0013) in the KA group were significantly superior to those in the BCS group 1 year postoperatively. There was no significant difference between the two groups observed in the rotational mismatch. In the BCS group, significant negative correlations were identified between the rotational mismatch and objective indicators, patient satisfaction, and functional activity scores but not in the KA group.

CONCLUSIONS

The short-term clinical results following KA-TKA showed superior objective knee indicators, patient satisfaction and functional activity scores. A negative correlation was observed between component rotational mismatch and the 2011 KSS subscales in the BCS group, compared to no relationship found between the two in the KA group. These findings suggested that KA-TKA has a relatively higher tolerance for rotational mismatch than BCS-TKA.

Current concept: personalized alignment total knee arthroplasty as a contrast to classical mechanical alignment total knee arthroplasty

Mechanical alignment (MA) total knee arthroplasty (TKA), with neutral leg alignment, mechanical component alignment, and parallel gaps, has achieved good long-term survival. Patient satisfaction, however, is not always perfect. In contrast to the MA, which aims for an ideal goal for all patients, an alternative has been proposed: kinematic alignment (KA)-TKA. In KA, the articular surface is replicated using components aligning with the three kinematic axes. KA-TKA has been gaining popularity, and in addition to the true or calipered KA, various derivatives, such as restricted KA, soft-tissue respecting KA, and functional alignments, have been introduced. Moreover, the functional approach encompasses several sub-approaches. This somewhat complicated scenario has led to some confusion. Therefore, the terminology needs to be re-organized. The term "personalized alignment (PA)" has been used in contrast to the MA approach, including all approaches other than MA. The term "PA-TKA" should be used comprehensively instead of KA and it represents the recent trends in distinct and unique consideration of each individual case. In addition to a comparison between MA and KA, we suggest that evaluation should be conducted to decide which approach is the best for an individual patient within the "personalized alignment" concept.

Indications, complications, and clinical outcomes of fixation and acute total hip arthroplasty for the treatment of acetabular fractures: A systematic review

PURPOSE

Acetabular fracture fixation can be challenging, especially in the elderly. Open reduction and internal fixation (ORIF) alone may not allow for early weight bearing and is associated with a high rate of secondary osteoarthritis; therefore, a combined hip procedure (CHP) or ORIF with acute total hip arthroplasty, may be beneficial in this population. The objective of this study was to perform a systematic review of all reported cases of CHP.

METHODS

PubMed, Embase, Scopus, and Cochrane databases were searched for studies analyzing acetabular fractures in the elderly managed with a combined hip procedure (CHP). The research was performed following the PRISMA guidelines. The included studies' methodological quality was evaluated using the MINORS score. The present study was registered on PROSPERO.

RESULTS

Eleven clinical studies were included in the final analysis. The mean age was 74.4 (63.2-78) years. Low-energy trauma was the most common mechanism of injury (64%). The most prevalent fracture pattern was the anterior column and posterior hemitransverse (ACPHT) (30.6%). The Kocher-Langenbeck approach was preferred for ORIF of posterior fractures and hip arthroplasty. The ilioinguinal approach and modified Stoppa were generally used for anterior fractures. The overall complication rate was 12.2%, and hip dislocation was the most frequent cause of reoperation (4.4%). The average Harris Hip Score reported postoperatively was 81.6 points, which was considered "good."

CONCLUSIONS

CHP is a safe treatment for elderly acetabular fractures with an acceptable complication and reoperation rate that results in good clinical outcomes.

LEVEL OF EVIDENCE

Level of evidence IV.

Restricted kinematic alignment is clinically non-inferior to mechanical alignment in the short and mid-term: A systematic review

BACKGROUND

In recent years, kinematic alignment (KA) is becoming a valid alternative to mechanical alignment (MA) in total knee arthroplasty (TKA). However, to avoid early failures, the restricted kinematic alignment (rKA) approach has been developed to restore native knee kinematics without reproducing extreme knee phenotype. This systematic review aims to evaluate clinical and radiological outcomes between rKA and MA for TKA.

METHODS

A systematic literature search was conducted following PRISMA guidelines on Pubmed, Scopus and Cochrane Library. The following search string was adopted: (((restricted kinematic) AND (mechanical)) AND (alignment)) AND (knee). We included studies that analyzed rKA versus MA in terms of clinical outcomes and complications with a minimum of 6 months of follow up. The following rKA- and MA-related data were evaluated: patient-reported outcome scores (PROMs), radiographic analysis of lower limb alignment, and complications. Criteria from the Methodological Index for Non-Randomized Studies were used to assess the methodological quality of the articles.

RESULTS

This systematic review included seven clinical studies with a total of 892 knees (471 for MA group and 421 for rKA group, respectively). Overall, post-operative PROMs were similar between rKA and MA. Moreover, rKA reached better results regarding Forgotten Joint Score and post-operative patient satisfaction. Finally, no higher complication rate was observed with the rKA approach.

CONCLUSION

The rKA aims to restore native knee kinematics, avoiding extreme deformities. Clinical outcomes are not inferior or even better for rKA compared with MA, without increasing the risk of short-middle-term implant failure. However, there is a high heterogeneity regarding the 'restricted' protocols used.

Reduced knee laxity and failure rate following anterior cruciate ligament reconstruction compared with repair for acute tears: a meta-analysis

BACKGROUND

Following anterior cruciate ligament (ACL) tears, both repair and reconstruction may be performed to restore joint biomechanics and proprioception. The present study compared joint laxity, patient-reported outcome measures (PROMs), and rate of failure following primary repair versus reconstruction for ACL ruptures.

METHODS

This meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pubmed, Google scholar, Embase, and Web of Science were accessed in September 2022. All the clinical investigations comparing repair versus reconstruction for primary ACL tears were accessed. Studies reporting data on multiple ligament injuries settings were not eligible.

RESULTS

Data from eight articles (708 procedures) were collected. The mean length of the follow-up was 67.3 ± 119.4 months. The mean age of the patients was 27.1 ± 5.7 years. Thirty-six percent (255 of 708 patients) were women. The mean body mass index (BMI) was 24.3 ± 1.1 kg/m². The mean time span from injury to surgery was 36.2 ± 32.3 months. There was comparability at baseline with regards to instrumental laxity, Lachman test, International Knee Document Committee (IKDC), and Tegner Scale (P > 0.1). Similarity between ACL reconstruction and repair was found in IKDC (P = 0.2) and visual analog scale (VAS) satisfaction (P = 0.7). The repair group demonstrated greater mean laxity (P = 0.0005) and greater rate of failure (P = 0.004).

CONCLUSION

ACL reconstruction may yield greater joint stability and lower rate of failure compared with surgical repair. Similarity was found in PROMs.

LEVEL OF EVIDENCE

III.

A robotic-assisted simulation of kinematic alignment in TKA leads to excessive valgus and internal rotation in valgus knees

PURPOSE

Strategies to further improve patient satisfaction after total knee arthroplasty include the introduction of new alignment philosophies and more precise instruments such as navigation and robotics. The aim of this study was to investigate the effect of a combination of image-based robotic assistance and the use of modern alignment strategies on the resulting joint line obliquity as well as femoral component rotation and to compare this between varus, neutral and valgus knees.

METHODS

This retrospective study included 200 patients who received a robotic-assisted total knee arthroplasty (MAKO®, Stryker) using functional alignment between 2018 and 2020. The patients were divided into a varus (103 patients), neutral (57 patients) and valgus (40 patients) group. The intraoperatively recorded bone cuts and resulting joint line obliquity were identified and compared to values obtained with a robotic computer simulation of kinematic alignment.

RESULTS

The mean femoral coronal alignment of the varus, neutral and valgus group, respectively, equalled 0.5° (± 1.1°), 1.1° (± 0.8°) and 1.6° (± 0.7°) of valgus with functional alignment and 2.1° (± 2.1°), 4.1° (± 1.7°) and 6.2° (± 1.7°) of valgus with kinematic alignment. The mean femoral axial alignment of the valgus group resulted in 0.8° (± 2.0°) of internal rotation with functional alignment and 3.9° (± 2.8°) of internal rotation with kinematic alignment. Overall, 186 knees (93%) could be balanced while respecting certain safe zones by using functional alignment as opposed to 54 knees (27% and none in the valgus group) when applying kinematic alignment. Kinematic alignment led to a combination of femoral component valgus and internal rotation of more than 3° in 22 valgus knees (55%), 10 neutral knees (18%) and 3 varus knees (3%) compared to none in each group when applying functional alignment with safe zones.

CONCLUSIONS

Robotic-assisted kinematic alignment leads to a combination of excessive valgus and internal rotation of the femoral component in valgus and to a lesser extent also in neutral knees when compared with functional alignment.

LEVEL OF EVIDENCE

IV.

Characterizing recurrent infections after one-stage revision for periprosthetic joint infection of the knee: a systematic review of the literature

BACKGROUND

Periprosthetic joint infection (PJI) of the knee represents a severe complication after 1.5% to 2% of primary total knee replacement. Although two-stage revision was considered the gold-standard treatment for PJI of the knee, in the last decades, more studies reported the outcomes of one-stage revisions. This systematic review aims to assess reinfection rate, infection-free survival after reoperation for recurrent infection, and the microorganisms involved in both primary and recurrent infection.

MATERIAL AND METHODS

A systematic review of all studies reporting the outcome of one-stage revision for PJI of the knee up to September 2022, according to PRISMA criteria and AMSTAR2 guidelines, was performed. Patient demographics, clinical, surgical, and postoperative data were recorded.

PROSPERO ID

CRD42022362767.

RESULTS

Eighteen studies with a total of 881 one-stage revisions for PJI of the knee were analyzed. A reinfection rate of 12.2% after an average follow-up of 57.6 months was reported. The most frequent causative microorganism were gram-positive bacteria (71.1%), gram-negative bacteria (7.1%), and polymicrobial infections (8%). The average postoperative knee society score was 81.5, and the average postoperative knee function score was 74.2. The infection-free survival after treatment for recurrent infection was 92.1%. The causative microorganisms at reinfections differed significantly from the primary infection (gram-positive 44.4%, gram-negative 11.1%).

CONCLUSION

Patients who underwent a one-stage revision for PJI of the knee showed a reinfection rate lower or comparable to other surgical treatments as two-stage or DAIR (debridement, antibiotics, and implant retention). Reoperation for reinfection demonstrates a lower success compared to one-stage revision. Moreover, microbiology differs between primary infection and recurrent infection. Level of evidence Level IV.

Postoperative full leg radiographs exhibit less residual coronal varus deformity compared to intraoperative measurements in robotic arm-assisted total knee arthroplasty with the MAKO™ system

PURPOSE

Robotic arm-assisted total knee arthroplasty (raTKA), currently a major trend in knee arthroplasty, aims to improve the accuracy of implant positioning and limb alignment. However, it is unclear whether and to what extent manual radiographic and navigation measurements with the MAKO™ system correlate. Nonetheless, a high agreement would be crucial to reliably achieve the desired limb alignment.

METHODS

Thirty-six consecutive patients with osteoarthritis and a slight-to-moderate varus deformity undergoing raTKA were prospectively included in this study. Prior to surgery and at follow-up, a full leg radiograph (FLR) under weight-bearing conditions was performed. In addition, a computed tomography (CT) scan was conducted for preoperative planning. The hip-knee-ankle angle (HKA), mechanical lateral distal femur angle (mLDFA), mechanical medial proximal tibial angle (mMPTA) and joint line convergence angle (JLCA) were measured in the preoperative and follow-up FLR as well as in the CT scout (without weight-bearing) by three independent raters. Furthermore, the HKA was intraoperatively assessed with the MAKO™ system before and after raTKA.

RESULTS

Significantly higher HKA values were identified for intraoperative deformity assessment using the MAKO system compared to the preoperative FLR and CT scouts (p = 0.006; p = 0.05). Intraoperative assessment of the HKA with final implants showed a mean residual varus deformity of 3.2° ± 1.9°, whereas a significantly lower residual varus deformity of 1.4° ± 1.9° was identified in the postoperative FLR (p < 0.001). The mMPTA was significantly higher in the preoperative FLR than in the CT scouts (p < 0.001). Intraoperatively, the mMPTA was adjusted to a mean of 87.5° ± 0.9° with final implants, while significantly higher values were measured in postoperative FLRs (p < 0.001). Concerning the mLDFA, no significant differences could be identified.

CONCLUSION

The clinical importance of this study lies in the finding that there is a difference between residual varus deformity measured intraoperatively with the MAKO™ system and those measured in postoperative FLRs. This has implications for preoperative planning as well as intraoperative fine-tuning of the implant position during raTKA to avoid overcorrection of knees with slight-to-moderate varus osteoarthritis.

LEVEL OF EVIDENCE

Level IV.

Kinematically Aligned Oxford Unicompartmental Knee Arthroplasty Using the Microplasty Instrumentation System

This technical note demonstrates kinematically aligned Oxford unicompartmental knee arthroplasty using the Microplasty instrumentation system with custom-made devices. The medial joint line is evaluated preoperatively; if it is aligned and parallel with the lateral joint line, they are considered to comprise the coronal knee joint line (CJL). In this case, the coronal inclination of a spoon gauge inserted into the medial joint space indicates the CJL. Otherwise, an accessory spoon is inserted and connected to the medial spoon to refer to the posterior condylar line, which is considered the CJL. The tibial cutting block is then connected without changing the inclination of the spoon and the coronal tilt of the tibial extramedullary rod is adjusted, which is implemented with a custom-made ankle yoke. The remainder of the steps is then identical to the conventional Microplasty procedure. This technique can imitate the cutting line to the CJL, which might be considered ideal from mechanical and kinematic perspectives.

Outcomes of modular stem for the treatment of periprosthetic femoral fracture: a systematic review of the literature

BACKGROUND

Periprosthetic femoral fractures (PFFs) are a frequent complication after total hip arthroplasty (THA). Both modular and non-modular tapered fluted titanium (TFT) stems could be used in total hip revisions (THRs). Nevertheless, the most appropriate femoral stem type is still under debate. The current systematic review aims to analyze the survival rate and all causes of stem revision, the overall complication rate and reason for reoperation, and patient reported outcome measures (PROMs) in THR for PFF using the modular tapered titanium stems (MTTS).

METHODS

A comprehensive search in four databases, PubMed, Scopus, Embase, and the Cochrane Database of Systematic Reviews databases, was performed, and following the PRISMA guidelines, a systematic review was conducted. Strict inclusion and exclusion criteria were applied, starting from 1,259 studies. The risk of bias was analyzed according to the MINORS tool system. Descriptive statistical analysis was performed for all data extracted.

RESULTS

Eighteen clinical studies were included in the qualitative analysis for a total of 775 patients enrolled. A mean MINORS criteria score of 9.8 [8-12] was reported. The overall survival of MTTS for PFF treatment was 95.4%, with an overall reintervention rate of 10.3% at an average follow-up of 4.5 years. Despite the use of modular components, postoperative hip instability remains the most frequent complication and cause of reintervention in these patients. In addition, a mean postoperative Harris Hip Score (HHS) of 78.1 was reported, which was considered acceptable given the high mean age of 74.1 years at the time of the revision.

CONCLUSIONS

Several therapeutic approaches and a wide variety of implants have been described in the literature for PFF management; however, no one solution has proven superior to others in the PFF treatment. MTTS has become a commonly used treatment option for Vancouver B2 and B3 fractures because they provide good clinical and radiological results with a reasonable survival rate. However, the complication rate of MTTS is still high.

Mechanical complications after total knee arthroplasty

INTRODUCTION

With the increasing demand for total knee arthroplasty (TKA) and the burden of revision TKA on the healthcare system, as well as the quality of life implications for patients, it is extremely important for surgeons to be able to anticipate and prevent TKA mechanical complications. Surgeons must be familiar with the different causes and mechanisms of TKA complications so that they can properly treat patients with failed TKAs and better avoid these complications.

AREAS COVERED

This review addresses TKA mechanical complications and provides context for the topic. A detailed review of surgical factors, implant factors, and patient factors that contribute to mechanical complications after TKA is provided. All of the literature cited in this review was gathered from the PubMed online database using different keywords based on the section of the manuscript.

EXPERT OPINION

As surgeons and engineers solve certain issues in TKA, new challenges will inevitably arise. We must continue to push forward and innovate from both a surgical technique and implant design perspective.

Postoperative clinical outcomes for kinematically, restricted kinematically, or mechanically aligned total knee arthroplasty: a systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Mechanically aligned total knee arthroplasty (MATKA) is a well-established procedure. Kinematically aligned TKA (KATKA) has been proposed to restore and preserve pre-arthritic knee anatomy. However, normal knee anatomy varies widely, and there have been concerns regarding restoring unusual anatomy. Accordingly, restricted KATKA (rKATKA) was introduced to reproduce constitutional knee anatomy within a safe range. This network meta-analysis (NMA) aimed to evaluate the clinical and radiological outcomes of the surgeries.

METHODS

We performed a database search on August 20, 2022, which included randomized controlled trials (RCTs) comparing any two of the three surgical TKA techniques for knee osteoarthritis. We conducted a random-effects NMA within the frequentist framework and evaluated confidence in each outcome using the Confidence in Network Meta-Analysis tool.

RESULTS

Ten RCTs with 1,008 knees and a median follow-up period of 1.5 years were included. The three methods might result in little to no difference in range of motion (ROM) between methods. In patient-reported outcome measures (PROMs), the KATKA might result in a slight improvement compared with the MATKA (standardized mean difference, 0.47; 95% confidence interval [CI], 0.16-0.78; very low confidence). There was little to no difference in revision risk between MATKA and KATKA. KATKA and rKATKA showed a slight valgus femoral component (mean difference [MD], -1.35; 95% CI, -1.95-[-0.75]; very low confidence; and MD, -1.72; 95% CI, -2.63-[-0.81]; very low confidence, respectively) and a slight varus tibial component (MD, 2.23; 95% CI, 1.22-3.24; very low confidence; and MD, 1.25; 95% CI, 0.01-2.49; very low confidence, respectively) compared with MATKA. Tibial component inclination and hip-knee-ankle angle might result in little to no difference between the three procedures.

CONCLUSIONS

KATKA and rKATKA showed similar ROM and PROMs and a slight variation in the coronal component alignment compared with MATKA. KATKA and rKATKA are acceptable methods in short- to mid-term follow-up periods. However, long-term clinical results in patients with severe varus deformity are still lacking. Surgeons should choose surgical procedures carefully. Further trials are warranted to evaluate the efficacy, safety, and subsequent revision risk.

Clinical and Radiographic Outcomes of Inversed Restricted Kinematic Alignment Total Knee Arthroplasty by Asia Specific (Huang’s) Phenotypes, a Prospective Pilot Study

Inverse restricted kinematic alignment (irKA) was modified from restricted kinematic alignment for total knee arthroplasty (TKA). This prospective single-center study aimed to evaluate the outcomes of irKA-TKA on all knee subtypes classified by Asia specific (Huang’s) phenotypes. A total of 96 knees that underwent irKA-TKA at one hospital between January 2018 and June 2020 were included, with 15 knees classified in Type 1, nine in Type 2, 15 in Type 3, 47 in Type 4, and 10 in Type 5 by Huang’s phenotypes. Outcomes were knee alignment measures and patient-reported satisfaction evaluated by the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and traditional Chinese version of the Forgotten Joint Score-12 (FJS-12). Follow-up was one year. Type 4 knee was most significantly corrected in all angles by irKA-TKA, followed by Type 2 and 3 knees. Type 5 and 1 knee were only significantly corrected in some angles. The correlation between FJS-12 and WOMAC was good at 6 months (Pearson correlation coefficient (r) = 0.74) and moderate at 6 weeks, 3 months, and 12 months during follow-up (r = 0.37~0.47). FJS-12 and WOMAC displayed comparable hip–knee–ankle angle cut-off value (4.71° vs. 6.20°), sensitivity (70.49% vs. 67.19%), specificity (84.00% vs. 85.71%), and Youden index (54.49% vs. 52.90%) in prediction of good prognosis. In conclusion, irKA-TKA corrects knee alignment in all knee types with increasing satisfaction for one-year follow-up. Knees with presurgical varus deformity are most recommended for irKA-TKA. Both presurgical scores of the traditional Chinese version of FJS-12 and WOMAC predict the prognosis of irKA-TKA.

Effect of Combined Kinematic Chain Exercise on Physical Function, Balance Ability, and Gait in Patients with Total Knee Arthroplasty: A Single-Blind Randomized Controlled Trial

Total knee arthroplasty (TKA) is an effective treatment for end-stage osteoarthritis. However, evidence of combined kinematic chain exercise (CCE) in early-phase rehabilitation after TKA remains lacking. This study investigated the effects of CCE training on physical function, balance ability, and gait in 40 patients who underwent TKA. Participants were randomly assigned to the CCE (n = 20) and open kinematic chain exercise (OKCE) groups (n = 20). The CCE and OKCE groups were trained five times a week (for 4 weeks) for 30 min per session. Physical function, range of motion (ROM), balance, and gait were assessed before and after the intervention. The time × group interaction effects and time effect as measured with the Western Ontario and McMaster Universities Osteoarthritis Index, ROM, Knee Outcome Survey-Activities of Daily Living, balancing ability (e.g., confidence ellipse area, path length, and average speed), and gait parameters (e.g., timed up-and-go test, gait speed, cadence, step length, and stride length) were statistically significant (p < 0.05). In the group comparison of pre- and postintervention measurements for all variables, the CCE group showed substantial improvements compared to the OKCE group (p < 0.05). Both groups showed significant within-group improvement from baseline to postintervention. Our results suggest that CCE training positively affects physical function, balance ability, and gait as an early intervention for patients undergoing TKA.

Is augmentation the best solution in partial anterior cruciate ligament tears? A literature systematic review and meta-analysis

Purpose

The appropriate management of partial anterior cruciate ligament (ACL) tears is still debated. There is a tendency in orthopedic clinical practice to prefer complete ACL reconstruction, while few surgeons perform ACL augmentation. The purpose of the present study is to evaluate the current evidence on the effectiveness of ACL augmentation compared with standard ACL reconstruction to assess whether ACL augmentation may be the treatment of choice in partial ACL injury.

Methods

According to PRISMA guidelines, literature research was performed in PubMed/Medline, Cochrane Library, Embase, Scopus, and Web of Science databases. A PICOS model was used, and a preliminary search resulted in 1101 articles. The methodological quality was assessed through ROBINS-I. A meta-analysis was conducted on postoperative Tegner, Lysholm scores and KT-1000 values between ACL augmentation and ACL reconstruction, and a p < 0.05 has been assumed as statistically significant. PROSPERO, ID: CRD42022343502.

Results

Seven papers were included. A total of 472 knees underwent ACL reconstruction, and 311 underwent ACL augmentation. A statistically significant discrepancy was found in the postoperative Tegner score in favor of ACL augmentation compared with ACL reconstruction (p < 0.05). Regarding the postoperative Lysholm score and KT-1000 measurement, no statistically significant difference was shown between ACL reconstruction and ACL augmentation (p > 0.05).

Conclusions

ACL augmentation has proved to be an effective and safe procedure and should be preferred to ACL reconstruction in partial ACL tears for the tendency to achieve better functional outcomes.

Established and Novel Risk Factors for 30-Day Readmission Following Total Knee Arthroplasty: A Modified Delphi and Focus Group Study to Identify Clinically Important Predictors

Thirty-day readmission following total knee arthroplasty (TKA) is an important outcome influencing the quality of patient care and health system efficiency. The aims of this study were (1) to ascertain the clinical importance of established risk factors for 30-day readmission risk and give clinicians the opportunity to suggest and discuss novel risk factors and (2) to evaluate consensus on the importance of these risk factors. This study was conducted in two stages: a modified Delphi survey followed by a focus group. Orthopaedic surgeons and anaesthetists involved in the care of TKA patients completed an anonymous survey to judge the clinical importance of risk factors selected from a systematic review and meta-analysis and to suggest other clinically meaningful risk factors, which were then discussed in a focus group designed using elements of nominal group technique. Eleven risk factors received a majority (≥50%) vote of high importance in the Delphi survey overall, and six risk factors received a majority vote of high importance in the focus group overall. Lack of consensus highlighted the fact that this is a highly complex problem which is challenging to predict and which depends heavily on risk factors which may be open to interpretation, difficult to capture, and dependent upon personal clinical experience, which must be tailored to the individual patient.

Highly cross-linked polyethylene versus conventional polyethylene in primary total knee arthroplasty: comparable clinical and radiological results at a 10-year follow-up

PURPOSE

Highly crosslinked polyethylene (HXLPE) was introduced in total knee arthroplasty (TKA) to reduce wear and consequent revisions for loosening due to conventional polyethylene (CPE) wear. This study aims to analyse whether HXLPE is as safe as CPE and could improve the TKA clinical and radiological results in a long-term follow-up.

METHODS

This retrospective study included all consecutive starting series of 223 patients with severe primary knee osteoarthritis (OA), with a minimum follow-up of 10 years treated between July 1st, 2007, and July 31st, 2010. After excluding patients who did not respect the inclusion and exclusion criteria, 128 patients were included in the analysis of this study. The patients were then divided into two groups according to the type of polyethylene (PE) implanted: CPE or HXLPE liners. All patients were evaluated for clinical and radiological parameters, causes and revision rates related to the type of PE implanted.

RESULTS

HXLPE appears to be as safe as CPE in TKA, reporting no higher revisions for osteolysis, prosthesis loosening, infection, and mechanical failure. Nevertheless, no statistically significant differences were found between the two groups in the clinical and radiological outcomes evaluated.

CONCLUSIONS

Clinical, radiological results, and revision rates are similar between HXLPE and CPE in TKA after 10 years of follow-up, although HXLPE benefits remain controversial.

LEVEL OF EVIDENCE

III.

Efficacy of Adductor Canal Block on Medial Knee Pain in Patients with Knee Osteoarthritis: A Randomized Single-Blind Placebo-Controlled Study

BACKGROUND

This study aimed to confirm the efficacy of ultrasound-guided adductor canal block (ACB) as a treatment option for medial knee pain caused by knee osteoarthritis (KOA).

METHODS

In total, 31 participants with medial knee pain due to KOA were randomized to either the ACB (ultrasound-guided ACB, n = 15) or placebo group (1 mL of 1% lidocaine, n = 16). The primary outcome was a numerical rating scale (NRS) for knee pain intensity comparing before and 4 weeks after injection. The secondary outcomes were the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), average daily number of analgesics consumed, average daily opioid consumption, and Timed Up and Go (TUG) test results before and 4 weeks after injection.

RESULTS

Participants' baseline characteristics were not significantly different between the groups, except for age. At 4 weeks post-injection, the NRS score in the ACB group significantly improved compared to that in the placebo group (p = 0.009). However, the WOMAC, average daily number of analgesics consumed, average daily opioid consumption, and TUG test results did not show significant differences.

CONCLUSION

ACB can be an effective treatment for reducing medial knee pain in patients with KOA.

No Significant Differences in Clinical and Radiographic Outcomes between PCL Retained or Sacrificed Kinematic Aligned Medial Pivot Total Knee Arthroplasty in Varus Knee

In the last decades, several surgical techniques, such as medial pivot (MP) philosophy and kinematic alignment (KA), have been introduced in total knee arthroplasty (TKA) to improve patients’ outcomes. This retrospective study aims to evaluate the clinical, radiographic, and functional results of PCL preservation or sacrifice in KA MP-TKA. A consecutive series of 147 patients older than 60, with a minimum follow-up of two years, were treated with TKA for severe primary knee osteoarthritis (OA) at the Department of Orthopedics and Traumatology between 1 January 2019, and 1 July 2020. After excluding those not meeting the inclusion criteria, 64 patients were included in the study analysis. Regarding radiographic outcomes, no statistically significant difference was observed between patients with preserved or sacrificed PCL (p > 0.05). A slight improvement in Knee Society Score (KSS), knee and function score, and FJS was observed for the PCL-preserved group, although this superiority tendency was not statistically significant (p > 0.05). PCL-preserved MA MP-TKA reported a statistically significant result in only two questions on the FJS questionnaire (p < 0.05). A slight, non-statistically significant improvement in active ROM was found in the PCL-sacrificed group (p > 0.05). No interventions or revisions were reported in this case series for all treated patients at the final follow-up. No significant differences were described in clinical, radiographic, and functional outcomes in preserved or sacrificed PCL KA MP-TKA. Although not significant, a slight trend toward better clinical outcomes was reported in PCL-preserved KA MP-TKA.

Effects of veterans' mental health service-connections on patient-reported outcomes following total joint arthroplasty

Background

Studies report poor outcomes of elective orthopaedic surgeries among civilian patients receiving Workers' Compensation (WC). However, little is known about surgical outcomes in veterans receiving similar benefits through the Veterans Affairs (VA) service-connected (SC) disability compensation program.

Methods

Veterans undergoing primary total hip arthroplasty (THA) or total knee arthroplasty (TKA) at a VA Medical Center between 07/2019-12/2021 were analyzed by SC status. Outcomes were evaluated using Hip disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS-JR) and Knee injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR) scores collected preoperatively and at 2- and 12-months postoperatively. Repeated measures mixed models were used to test for the effect of SC on HOOS-JR/KOOS-JR scores, controlling for baseline age, sex, and Charlson Comorbidity Index (CCI). SC and baseline joint function (stratified into quartiles using baseline HOOS-JR/KOOS-JR scores) were analyzed for effects on achieving substantial clinical benefit (SCB) at 12-month follow-up.

Results

The analysis included 67 hips and 142 knees. SC and non-SC (NSC) veterans had similar baseline HOOS-JR/KOOS-JR and CCI. HOOS-JR remained similar between groups through 12 months (79.9 ± 19.2 vs. 82.7 ± 18.8) as did KOOS-JR (70.4 ± 15.6 vs. 74.6 ± 15.3). The designation of any SC and mental health SC reached significance for KOOS-JR (P = 0.034 and P = 0.032, respectively). For HOOS-JR and KOOS-JR, baseline function score quartile significantly influenced final score (P < 0.001), with patients in the lowest quartiles (i.e., worst baseline function) exhibiting significantly greater improvements than patients in higher quartiles.

Conclusions

Mental health SC and high preoperative functional status are variables that may have unfavorable influences on self-reported outcomes of TKA in veteran patients. SC status does not appear to influence the outcomes of THA or the likelihood of achieving SCB after either THA or TKA. Regardless of SC status, most veterans can expect significant clinical improvements after total joint arthroplasty.

Could anterior closed-wedge high tibial osteotomy be a viable option in patients with high posterior tibial slope who undergo anterior cruciate ligament reconstruction? A systematic review and meta-analysis

PURPOSE

This study aims to examine the clinical and radiological outcomes of patients who underwent ACL reconstruction (ACLR) combined with anterior closed-wedge high tibial osteotomy (ACW-HTO) for posterior tibial slope (PTS) reduction to investigate the efficacy of this procedure in improving anterior knee stability and preventing graft failure in primary and revision ACLR.

METHODS

A literature search was conducted in six databases (PubMed, Embase, Medline, Web of Science, Cochrane, and Scopus). The study was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. The initial screening identified 1246 studies. Each eligible clinical article was screened according to the Oxford Centre for Evidence-Based Medicine 2011 levels of evidence (LoE), excluding clinical studies of LoE V. Quality assessment of the articles was performed using the ROBINS-I methodological evaluation. This systematic review and meta-analysis was registered on the International Prospective Register of Systematic Reviews (PROSPERO). For the outcomes that were possible to perform a meta-analysis, a p < 0.05 was considered statistically significant.

RESULTS

Five clinical studies were included in the final analysis. A total of 110 patients were examined. Pre- and post-operative clinical and objective tests that assess anteroposterior knee stability, PTS, clinical scores, and data on surgical characteristics, complications, return to sports activity, and graft failure after ACLR were investigated. A meta-analysis was conducted using R software, version 4.1.3 (2022, R Core Team), for Lysholm score and PTS outcomes. A statistically significant improvement for both these clinical and radiological outcomes (p < 0.05) after the ACW-HTO surgical procedure was found.

CONCLUSION

ACLR combined with ACW-HTO restores knee stability and function with satisfactory clinical and radiological outcomes in patients with an anterior cruciate ligament injury associated with a high PTS and seems to have a protective effect from further ruptures on the reconstructed ACL.

LEVEL OF EVIDENCE

Level IV.