Extramedullary versus intramedullary femoral alignment technique in total knee arthroplasty: a meta-analysis of randomized controlled trials

Robotics in total knee replacement: Current use and future implications

Robotic total knee replacement (TKR) surgery has evolved over the years with the aim of improving the overall 80% satisfaction rate associated with TKR surgery. Proponents claim higher precision in executing the pre-operative plan which results in improved alignment and possibly better clinical outcomes. Opponents suggest longer operative times with potentially higher complications and no superiority in clinical outcomes alongside increased costs. This editorial will summarize where we currently stand and the future implications of using robotics in knee replacement surgery.

Primary total knee arthroplasty in hemophilic arthropathy

Advanced hemophilic knee arthropathy is a frequent and devastating manifestation of severe hemophilia with significant implications for activities of daily living. Hemophilic arthropathy is caused by repeated bleeding, resulting in joint degeneration, pain, deformity and disability. In patients with hemophilia and advanced disease, total knee arthroplasty (TKA) has proven to be the most successful intervention, improves physical function and reduces knee pain. Hemophilic patients carry additional risks for complications and required specific pre/postoperative considerations. Expert treatment center should be used to improve patient outcome. Hemophilic patients present significant surgical challenges such as joint destruction, bone loss, severe ankylosis and oligoarticular involvement. The surgeon performing the arthroplasty must be experienced to manage such problems.

Learning curve of robot-assisted total knee arthroplasty and its effects on implant position in asian patients: a prospective study

BACKGROUND

Robot-assisted total knee arthroplasty (r-TKA) can reportedly achieve more accurate implant positioning than conventional total knee arthroplasty (c-TKA), although its learning curve is controversial. Moreover, few studies have investigated r-TKA in Asians, who have different anatomical characteristics. This study aimed to determine the learning curve for r-TKA and compare implant positions between r-TKA and c-TKA according to the learning curve in Asian patients.

METHODS

This prospective study included 50 consecutive c-TKAs (group C), followed by 50 consecutive r-TKAs conducted using the MAKO robotic system (Stryker, USA). Cumulative summation analyses were performed to assess the learning curve for operative time in r-TKA. Accordingly, the r-TKA cases were divided into the initial (group I) and proficiency cases (group P). The femoral and tibial component positions in the coronal, sagittal, and axial planes and lower limb alignment were compared among the three groups.

RESULTS

r-TKA was associated with a learning curve for operative time in 18 cases. The operative time was significantly shorter in groups C and P than that in group I, with no significant difference between groups C and P. Groups I and P demonstrated fewer outliers with respect to lower limb alignment, femoral component coronal position, axial position, and tibial component sagittal position than those in group C, with no significant difference between groups I and P.

CONCLUSION

The operative time did not differ significantly between r-TKA and c-TKA after the learning curve. Surgeons could expect more accurate and reproducible lower limb alignment and implant positioning with r-TKA in Asian patients, irrespective of the learning curve.

Is the femoral intramedullary alignment already actual in total knee arthroplasty?

Clinical outcomes and overall alignment after total knee arthroplasty (TKA) depend on femoral component positioning in the sagittal and the coronal plane, making choice of the distal femoral cutting guide crucial. Currently, there is no consensus on the potential advantage of an extramedullary (EM) guide compared to an intramedullary (IM) guide in TKA. The IM guide is the most widely used system for making the distal femoral cut although evidence for its superiority over the EM guide is lacking. However, inaccuracies arising with the IM guide include location of the rod entry point in the coronal plane, femoral canal diameter, femoral bowing, and structural features of the rod. Furthermore, the invasive procedure is associated with increased risk of postoperative blood loss, thromboembolic complications, and intraoperative fractures. While the EM guide has no such difficulties, its accuracy depends on the instruments used. Studies have reported results not inferior to the IM guide and a lower number of postoperative complications. Patient-specific instrumentation (PSI) and robotic and computer-assisted TKA have achieved excellent clinical and radiographic results and can overcome the problems inherent to the IM and the EM guide. Authors performed a systematic review of the literature and proposed a narrative review to summarize the characteristics of the IM and the EM guide and compare the advantages and disadvantages of each, as well as their limitations in comparison with new technologies. Authors also expressed their expert opinion.

Comparison of intramedullary versus extramedullary alignment technique in total knee arthroplasty: A PRISMA-compliant meta-analysis

BACKGROUND

This meta-analysis aimed to compare the efficacy of intramedullary and extramedullary femoral alignment technique in treating total knee arthroplasty (TKA) patients.

METHODS

PubMed, Embase, Cochrane library, Chinese National Knowledge Infrastructure, and Weipu databases were electronically searched. Potential clinical studies that investigated the effect and safety of intramedullary versus extramedullary femoral alignment technique in TKA patients were searched. The primary outcome was lower limb coronal alignment. Stata 12.0 was used for meta-analysis.

RESULTS

This meta-analysis included 12 prospective randomized controlled studies that reported data on 935 TKA patients. No significant difference was noted in lower limb coronal alignment, coronal alignment of femoral component, sagittal alignment of femoral component and tibial slope between intramedullary and extramedullary alignment techniques ( P  > .05). Further, extramedullary alignment technique significantly decrease the total blood loss than intramedullary alignment technique (weighted mean difference: -86.52; 95% confidence interval: -115.05--57.99; P  = .000) and subsequently transfusion rate (risk ratio: 0.57; 95% confidence interval: 0.41-0.79; P  = .000). Finally, there was no significant difference between intramedullary and extramedullary alignment techniques in terms of the total complications ( P  > .05).

CONCLUSIONS

The present meta-analysis showed that intramedullary and extramedullary femoral alignment technique had comparable precise profiles. And extramedullary femoral alignment technique could reduce blood loss and blood transfusion. Total complications were comparable between the groups. More randomized controlled trials with large samples are required to verify the comparison of intramedullary and extramedullary femoral alignment technique in TKA patients.

Evaluation of Blood Loss in Conventional vs MAKOplasty Total Knee Arthroplasty

Background

Methods

Results

Conclusions

Comparison of serum inflammatory indicators and radiographic results in MAKO robotic-assisted versus conventional total knee arthroplasty for knee osteoarthritis: a retrospective study of Chinese patients

BACKGROUND

The purpose of this study was to compare the serum inflammatory indicators and radiographic results of conventional manual total knee arthroplasty (CM-TKA) with those of MAKO-robotic assisted total knee arthroplasty (MA-TKA).

METHODS

We retrospectively analysed 65 patients with knee osteoarthritis who underwent unilateral TKA from December 2020 to November 2021 in our department, which included 34 patients who underwent MA-TKA and 31 patients who underwent CM-TKA. The tourniquet time and estimated blood loss (EBL) were compared between the two groups. Knee function was evaluated using range of motion (ROM), functional score and pain score. Leukocytes, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), interleukin-6 (IL-6), creatine kinase (CK), and neutrophil-to-lymphocyte ratio (NLR) were recorded at 3 time points (preoperative, and on the first and third postoperative days). The hip-knee-ankle angle (HKA) and the femoral and tibial component angles in the coronal and sagittal planes were used for postoperative radiographic evaluation.

RESULTS

The postoperative MA-TKA group had less EBL (496.9 ± 257.8 vs. 773.0 ± 301.3 ml, p < 0.001). There was no significant difference in knee function scores at 6 weeks postoperatively (p > 0.05). IL-6 levels were significantly lower in the MA-TKA group on the 1st postoperative day (11.4 (5.2, 21.0) vs. 24.6 (86.3, 170.8), p = 0.031). This difference in inflammatory indices became more pronounced at 72 hours after the operation because CRP, ESR, IL-6, and CK values were significantly lower in the MA-TKA group on the 3rd postoperative day (72 h) (p < 0.05). Postoperative radiographic examinations performed 2 days after the MA-TKA group suggested that only 2 cases of HKA had outlier values, which was remarkably better than the 12 cases found in the CM-TKA group (5.9% vs. 38.7%, p < 0.001). The frontal femoral component was significantly closer to the expected value of 90° in the MA-TKA group (90.9 (90.5, 92.3) vs. 92.4 (91.3, 93.7), p = 0.031). The remaining imaging evaluation parameters were not significantly different between the two groups (p > 0.05).

CONCLUSIONS

In Chinese patients with OA, there was a milder systemic inflammatory response in the early postoperative period after MA-TKA compared to that of CM-TKA, as well as better radiographic outcomes. However, the tourniquet time was prolonged, and no advantages were observed in terms of functional score or pain score in the short-term follow-up.

Total Hospital Costs and Readmission Rate of Patient-Specific Instrument in Total Knee Arthroplasty Patients

Despite advancements in surgical technique and component design, implant loosening, stiffness, and instability remain leading causes of total knee arthroplasty (TKA) failure. Patient-specific instruments (PSI) aid in surgical precision and in implant positioning and ultimately reduce readmissions and revisions in TKA. The objective of the study was to evaluate total hospital cost and readmission rate at 30, 60, 90, and 365 days in PSI-guided TKA patients. We retrospectively reviewed patients who underwent a primary TKA for osteoarthritis from the Premier Perspective Database between 2014 and 2017 Q2. TKA with PSI patients were identified using appropriate keywords from billing records and compared against patients without PSI. Patients were excluded if they were < 21 years of age; outpatient hospital discharges; evidence of revision TKA; bilateral TKA in same discharge or different discharges. 1:1 propensity score matching was used to control patients, hospital, and clinical characteristics. Generalized Estimating Equation model with appropriate distribution and link function were used to estimate hospital related cost while logistic regression models were used to estimate 30, 60, and 90 days and 1-year readmission rate. The study matched 3,358 TKAs with PSI with TKA without PSI patients. Mean total hospital costs were statistically significantly (p < 0.0001) lower for TKA with PSI ($14,910; 95% confidence interval [CI]: $14,735-$15,087) than TKA without PSI patients ($16,018; 95% CI: $15,826-$16,212). TKA with PSI patients were 31% (odds ratio [OR]: 0.69; 95% CI: 0.51-0.95; p-value = 0.0218) less likely to be readmitted at 30 days; 35% (OR: 0.65; 95% CI: 0.50-0.86; p-value = 0.0022) less likely to be readmitted at 60 days; 32% (OR: 0.68; 95% CI: 0.53-0.88; p-value = 0.0031) less likely to be readmitted at 90 days; 28% (OR: 0.72; 95% CI: 0.60-0.86; p-value = 0.0004) less likely to be readmitted at 365 days than TKA without PSI patients. Hospitals and health care professionals can use retrospective real-world data to make informed decisions on using PSI to reduce hospital cost and readmission rate, and improve outcomes in TKA patients.

A ligament tensor-guided extramedullary alignment technique for distal femoral cut in total knee replacement: results at a minimum 3 years follow-up

BACKGROUND

Femoral intramedullary canal referencing is used by most knee arthroplasty systems for distal femoral cut; to avoid the opening of the femoral canal different solutions have been presented such as navigation, patient-specific instruments (PSI) or the use of an extramedullary device. The FuZion^® system is a tensor device, created to merge the two main techniques for performing a total knee arthroplasty: the ligament balancing and measured resection techniques. Our idea was to use the tensor as an extramedullary cutting guide for the distal femoral cut, based on a 90° tibial resection.

METHODS

A total of 110 patients were operated on with this technique. Patients were evaluated with weight-bearing long-standing X-rays, knee a-p and lateral views, validated PROMs (Oxford Knee Score, EQ-5D and EQ-VAS), the Knee Society Scoring System (KSS) and the Forgotten Joint Score (FJS). Minimum follow up was 3 years (range 38-50 months).

RESULTS

Complete results were available for 104 patients (5 were lost in follow up and 1 died). Significant improvements were registered for all the evaluated scores from pre-op to the final follow up. Pre-op long-standing X-rays showed 21 valgus knees (20%) with a mean HKA of 187.6° (± 3.2°), 70 varus knees (62%) with a mean 172.2° (± 3.7°) HKA and 19 neutrally aligned knees, with a mean HKA of 179.5° (0 ± 2°). The radiographic evaluation at 3 months post-op showed 20 valgus knees (mean HKA 183.7° ± 1.5°), 67 varus knees (mean HKA 176.1° ± 1.8°) and 23 neutrally aligned knees with a mean HKA of 179.3° (0 ± 2°). At final follow up the survival rate was 100% for revision of the implant as the endpoint. With any reoperation as the endpoint Kaplan-Meier survival estimate showed a survival rate of 95.1% at 3 years.

CONCLUSIONS

This technique for performing a ligament driven alignment in total knee arthroplasty showed encouraging clinical outcomes at mid-term follow up leaving a residual deformity on the coronal plane.

Extramedullary femoral alignment system in total knee arthroplasty: Accuracy in relation of severity and different types of varus

Objectives

We assessed the accuracy of an extramedullary guide system for femoral component alignment in TKA.

Methods

We retrospectively analysed 87 total knee arthroplasties using a newly developed extramedullary guide system.

Results

Correct postoperative coronal plane femoral component, with deviation from neutral alignment by 3° or less, was found in 87% of the study population. The percentages were 100%, 91% and 79% for HKA of 0-3°, 3-10° and >10°respectively.

Conclusion

The correct use of the extramedullary guide system allows the restoration of the neutral mechanical axes of the lower limb, especially in cases of limited varus deformity.

Comparison of early results of total knee replacement performed with Zimmer iASSIST versus conventional technique

Background:

Zimmer iASSIST knee is an accelerometer-based navigation system with the aim of achieving better alignment in total knee arthroplasty (TKA). We have started using this system since early 2016. This is a retrospective case–control study, which aims to compare the radiological alignment, operation time, and blood loss of TKAs performed using the iASSIST system and those using conventional techniques.

Materials and Methods:

42 TKAs using Zimmer iASSIST and 44 TKAs using conventional instrumentation were recruited. The overall coronal alignment and the coronal and sagittal alignment of the femoral and tibial component were compared. For coronal alignment, additional analysis of the absolute deviation from neutral mechanical axis was performed to avoid canceling out of varus/valgus deviation. The number of outliers, operation time, and blood loss in terms of maximal hemoglobin drop were also compared.

Results:

When comparing the alignment of the iASSIST group with the conventional group, there were no significant differences ( p > 0.05) in the number of outliers, mean coronal alignments, mean deviation from neutral coronal mechanical axis (2.9° vs. 2.9°), and femoral component flexion angle (4.9° vs. 4.7°). The difference in the mean tibial component posterior slope was significant (5.7° vs. 7.1°, p < 0.05). The mean operation time was significantly longer by 13 min ( p < 0.05) in the iASSIST group. There were no significant differences in the mean hemoglobin drop between the two groups.

Conclusion:

The results demonstrated no significant differences in terms of coronal radiological alignment, femoral flexion angle, outliers, and blood loss between iASSIST and conventional technique. There was a small but statistically significant difference in tibial posterior slope. The iASSIST group needed a longer operation time.

A simple technique to perform total knee replacement without violating the femoral canal: early clinical results on a cohort of 303 patients

BACKGROUND

It is becoming increasingly common to find patients candidate for total knee replacement with inaccessible femoral canal due to long femoral hip stems, osteo-synthetic hardware or diaphyseal mal-unions. To treat those patients avoiding complex and expensive procedures, we developed an innovative surgical technique based on a novel device called extra-medullary alignment system. We initially employed this technique in 18 cases with inaccessible femoral canal. Early results were so encouraging that we adopted this technique also for our standard cases.

MATERIALS AND METHODS

We report here our findings with a first series of 303 consecutive patients performed employing this technique. All patients received a cemented cruciate-retaining mobile-bearing total knee. Patients were followed for a minimum of 2 years and evaluated employing the Knee Society Score and the Oxford questionnaire. We also recorded the surgical time and any complication occurred intra-operatively and postoperatively. Patients' X-rays were as well evaluated.

RESULTS

No patient was lost to follow-up. Patients group average Knee Society and Oxford scores improved, respectively, from 45 and 16 pre-op to 92 and 45 at 2-year follow-up. Those results were compared and found aligned to those reported by similar historic control groups. Prosthetic implant alignment and surgical time demonstrated to be similar the one obtained using endo-medullary-referenced instruments. In this series, we did not observe any meaningful complication.

CONCLUSIONS

The extra-medullary alignment system seems to be a simple and reliable technique enabling to perform total knee replacement in a truly minimal invasive manner avoiding femoral canal violation.

LEVEL OF EVIDENCE

IV.

A novel surgical technique to perform total knee arthroplasty in patients with inaccessible femoral medullary canal

Not seldom Surgeons have to deal with total knee cases where the femoral intramedullary canal is not accessible due to hardware still in place, long hip stems or diaphyseal mal-unions, so intra-medullary referenced instrumentations cannot be employed. We developed a novel instrument called EMAS (Extra Medullary Alignment System) able to help addressing those cases in a simple and reproducible way avoiding the use of more complex and expensive technologies. We present the results achieved using EMAS on 18 of those difficult cases with a maximum follow-up of 7 years as well as our experience using EMAS in our standard practice.

A novel extramedullary technique to guide femoral bone preparation in mobile unicompartmental knee arthroplasty based on tibial cut and overall alignment

Background

The mobile Oxford unicompartmental knee arthroplasty (UKA) implant has been widely used with an intramedullary guide for femoral preparation. We modified the femoral guide technique based on the tibial cut first and spacer block technique. This study was performed to determine the radiographic accuracy and early clinical outcomes of the extramedullary method.

Methods

We retrospectively evaluated 50 consecutive patients who underwent UKA using the extramedullary technique. An equal number of patients who underwent UKA with the conventional technique were matched as the control group. Clinical outcomes were evaluated in terms of the operating time, blood loss, range of motion, and Hospital for Special Surgery score. Radiographic accuracy was evaluated by the implant position and alignment in the coronal and sagittal planes.

Results

The mean follow-up period was 39.76 ± 5.77 months. There were no differences in the postoperative Hospital for Special Surgery score, range of motion, or hip-knee-ankle angle between the two groups. The operating time in the extramedullary group was shorter than that in the conventional group (54.78 ± 7.95 vs. 59.14 ± 10.91 min, respectively; p = 0.025). The drop in hemoglobin after 3 days was only 12.34 ± 4.98 g/L in the extramedullary group which was less than that in the conventional group (p = 0.001). No significant differences were found in the postoperative coronal and sagittal angles between the two groups. Acceptable radiographic accuracy of the implant alignment and position was achieved in 92% of patients in the extramedullary group and 96% of patients in the conventional group.

Conclusions

The radiographic and clinical results of the extramedullary technique were comparable with those of the conventional technique with the advantage of no intramedullary interruption, less blood loss, a shorter operating time, and more rapid recovery. As the technique depends on the accurate tibial cut and overall alignment, we do not recommend it to surgeons without high volume experiences.

Trial registration

Retrospectively registered

Level of evidence

IV, retrospective study

TKA with retained hardware guided by intraoperative ultrasonography - a case report

Background

When a conservative management of gonarthrosis yields unsatisfactory results, a total knee arthroplasty (TKA) is recommended as an alternative approach. The implant survival is crucial for the long-term success of the procedure. However, in case of patients with retained hardware after past orthopedic procedures, providing correct alignment of the implant, which contributes to its longevity, is especially challenging. Here we present the use of an intra-operative ultrasonography for implant positioning in a 83-year-old male, undergoing TKA, without hardware removal, which was contraindicated due to his advanced age and comorbidities. Other imaging modalities taken into consideration are also described.

Case presentation

The right knee joint was approached with anterior incision. A femoral guide was introduced extramedullary. Ultrasonography was used to pinpoint the center of the femur’s head. Tibial’s guide was introduced intramedullary followed by a standard cut of the proximal part. Cemented ZIMMER NEXGEN prosthesis was used. Layered closure was applied. The placement of implant in neutral axis was confirmed on radiographs.

Conclusions

Our case demonstrates that ultrasonography might be helpful during TKA-procedure for implant positioning. However, more studies are needed to evaluate accuracy and application of ultrasound in the intraoperative settings.

Blood management in fast-track orthopedic surgery: an evidence-based narrative review

BACKGROUND AND PURPOSE

Innovations able to maintain patient safety while reducing the amount of transfusion add value to orthopedic procedures. Opportunities for improvement arise especially in elective procedures, as long as room for planning is available. Although many strategies have been proposed, there is no consensus about the most successful combination. The purpose of this investigation is to identify information to support blood management strategies in fast-track total joint arthroplasty (TJA) pathway, to (i) support clinical decision making according to current evidence and best practices, and (ii) identify critical issues which need further research.

METHODS AND MATERIALS

We identified conventional blood management strategies in elective orthopedic procedures. We performed an electronic search about blood management strategies in fast-track TJA. We designed tables to match every step of the former with the latter. We submitted the findings to clinicians who operate using fast-track surgery protocols in TJA at our research hospital.

RESULTS

Preoperative anemia detection and treatment, blood anticoagulants/aggregants consumption, transfusion trigger, anesthetic technique, local infiltration analgesia, drainage clamping and removals, and postoperative multimodal thromboprophylaxis are the factors which can add best value to a fast-track pathway, since they provide significant room for planning and prediction.

CONCLUSION

The difference between conventional and fast-track pathways does not lie in the contents of blood management, which are related to surgeons/surgeries, materials used and patients, but in the way these contents are integrated into each other, since elective orthopedic procedures offer significant room for planning. Further studies are needed to identify optimal regimens.