Effects of Reduction Osteotomy on Gap Balancing During Total Knee Arthroplasty for Severe Varus Deformity

Lateralized position of femoral and tibial components during posterior-stabilized total knee arthroplasty leads to better functional outcomes

BACKGROUND

The mediolateral position and postoperative translation of the femoral and tibial components relative to the respective bones after total knee arthroplasty (TKA) have not yet been investigated. The purpose of the current study was to investigate the effect of the mediolateral position of the femoral and tibial components on clinical outcomes including muscle strength and ambulatory function.

METHODS

A total of 86 consecutive knees were included. The mediolateral positions of the femoral and tibial components were measured on the postoperative long-leg radiographs. The mediolateral position of the femoral and tibial components was defined relative to the femoral distal anatomical axis and the tibial mechanical axis. The lateral position of the component was denoted as positive. The lateral translation of the femoral and tibial components was defined as the distance between the preoperative femoral and tibial centers and the postoperative center of the respective component. The Knee Society Score (KSS), New Knee Society Score (2011 KSS), and the Timed Up and Go (TUG) test results were evaluated 2 years postoperatively. Spearman's correlation coefficient was calculated.

RESULTS

The lateral position of the femoral component was significantly positively correlated with KSS function score (ρ = 0.250, p = 0.020), 2011 KSS functional activities (ρ = 0.258, p = 0.017), and TUG values (ρ = - 0.241, p = 0.027). The lateral translation of the tibial component was significantly correlated with knee extension strength (ρ = 0.259, p = 0.017).

CONCLUSIONS

The lateralized position of the femoral and tibial components positively influenced postoperative knee function. When the width of the component does not fit the resected surface, a lateralized position of the femoral and tibial components with respect to the respective bones can be recommended for better functional outcomes.

Correction of severe varus deformity in total knee arthroplasty with the technique of tibial plateau reduction

BACKGROUND

The optimal soft tissue release technique for severe varus total knee arthroplasty (TKA) remains controversial. The technique of tibial plateau reduction was suggested for severe varus deformity during TKA. The purpose of this study was to evaluate the clinical and radiological outcomes of the technique of tibial plateau reduction.

METHODS

Fifty-one knees (39 patients) with a mechanical femoro-tibial angle (MFTA) greater than 15° treated with TKA was presented. The clinical and radiographic data were gathered prospectively. The patients were divided into two groups according to the preoperative angle: Group A comprised patients with a preoperative MFTA less than or equal to 20°, while Group B included patients with a preoperative MFTA greater than 20°.

RESULTS

Among the 51 knees, 46 knees (90.2%) had femoro-tibial component size mismatch. The KSS-KS improved from preoperative 39.9 ± 11.3 points (range:18-68 points) to 92.3 ± 5.2 points (range: 83-100 points) at the final follow up (t = 30.141, P < 0.001); the KSS-FS improved from preoperative 48.0 ± 11.5 points (range: 31-71 points) to 87.2 ± 8.7 points (range: 63-100 points) at the final follow up (t = 19.413, P < 0.001). The mean MFTA was corrected from 21.0 ± 4.7° preoperatively to 2.9 ± 1.8° at the latest follow up (P < 0.001). The preoperative MFTA was less than or equal to 20° in 27 knees (Group A), and greater than 20° in 24 knees (Group B). The mean postoperative MFTA was 1.9 ± 0.9° in Group A, and 4.1 ± 1.7° in Group B (P < 0.001). The neutral limb alignment was reached in 26 knees (96.3%) in group A, which was significantly higher than that in group B (29.7%) (P = 0.019).

CONCLUSIONS

The technique of tibial plateau reduction provided satisfactory clinical and radiological outcomes without instability for severe varus TKA. However, surgeons should remain aware that the greater the preoperative varus deformity, the greater the postoperative residual varus deformity, and that there is a high incidence of femoro-tibial component size mismatch using the technique.

Digital TKA Alignment Training with a New Digital Simulation Tool (Knee-CAT) Improves Process Quality, Efficiency, and Confidence

Individual alignment techniques have been introduced to restore patients' unique anatomical variations during total knee arthroplasty. The transition from conventional mechanical alignment to individualised approaches, with the assistance of computer and/or robotic technologies, is challenging. The objective of this study was to develop a digital training platform with real patient data to educate and simulate various modern alignment philosophies. The aim was to evaluate the training effect of the tool by measuring the process quality and efficiency, as well as the post-training surgeon's confidence with new alignment philosophies. Based on 1000 data sets, a web-based interactive TKA computer navigation simulator (Knee-CAT) was developed. Quantitative decisions on bone cuts were linked to the extension and flexion gap values. Eleven different alignment workflows were introduced. A fully automatic evaluation system for each workflow, with a comparison function for all workflows, was implemented to increase the learning effect. The results of 40 surgeons with different experience levels using the platform were assessed. Initial data were analysed regarding process quality and efficiency and compared after two training courses. Process quality measured by the percentage of correct decisions was increased by the two training courses from 45% to 87.5%. The main reasons for failure were wrong decisions on the joint line, tibia slope, femoral rotation, and gap balancing. Efficiency was obtained with a reduction in time spent per exercise from 4 min 28 s to 2 min 35 s (42%) after the training courses. All volunteers rated the training tool as helpful or extremely helpful for learning new alignment philosophies. Separating the learning experience from OR performance was mentioned as one of the main advantages. A novel digital simulation tool for the case-based learning of various alignment philosophies in TKA surgery was developed and introduced. The simulation tool, together with the training courses, improved surgeon confidence and their ability to learn new alignment techniques in a stress-free out-of-theatre environment and to become more time efficient in making correct alignment decisions.

Medial osteophyte resection width correlates with correction of the medio-lateral component gap imbalance during posterior-stabilized total knee arthroplasty

BACKGROUND

There is a lack of robust evidence for a correlation between the medial osteophyte resection and correction of the medio-lateral gap imbalance during total knee arthroplasty. The purpose of the present study was to quantify the effect of osteophyte resection on the medio-lateral component gap imbalance during posterior-stabilized total knee arthroplasty.

METHODS

Forty-five cases of primary posterior-stabilized total knee arthroplasty using the measured resection technique with posterior-stabilized prosthesis for varus knee osteoarthritis were reviewed. Medial and lateral joint gaps at 0°, 10°, 45°, and 90° of flexion, and maximum flexion were measured intraoperatively before and after the osteophyte resection. The relationship between medial osteophyte resection width and change of joint varus angle and medial component gap were assessed using Pearson's correlation coefficient.

FINDINGS

Medial component gap and joint varus angle values at post medial osteophyte resection were significantly larger and lower than at pre-resection (Medial gap: pre 9.5 ± 1.8 mm, post 10.3 ± 1.8 mm, P < 0.001, Joint angle: pre 5.2 ± 2.9°, post 4.2 ± 2.9°, P < 0.001). There was no significant difference between pre and post medial osteophyte resection in lateral component gaps. Per each 1 mm of medial osteophyte resection width, increases of 0.13 mm medial component gap and 0.2° valgus were observed (Medial gap: r = 0.38, P < 0.001, Joint angle: r = 0.38, P < 0.001).

INTERPRETATION

Medial osteophyte resection increases the medial component gap without lateral component gap increase, while decreasing the joint varus angle in primary posterior-stabilized total knee arthroplasty for varus knee osteoarthritis. Osteophyte resection width was found to correlate with correction of the medio-lateral component gap imbalance.

Osteotomies and Total Knee Arthroplasty: Systematic Review and Meta-Analysis

Total knee replacement (TKA) is a frequent modality performed in patients with osteoarthritis. Specific circumstances can make it much more difficult to execute successfully, and additional procedures such as osteotomy may be required. The aim of this study was to perform a meta-analysis and systematic review of osteotomies combined with TKA.

METHODS

In June 2022, a search PubMed, Embase, Cochrane, and Clinicaltrials was undertaken, adhering to PRISMA guidelines. The search included the terms "osteotomy" and "total knee arthroplasty".

RESULTS

Two subgroups (tibial tubercle osteotomy and medial femoral condyle osteotomy) were included in the meta-analysis. Further subgroups were described as a narrative review. The primary outcome showed no significant difference in favor to TTO. Secondary outcomes showed improved results in all presented subgroups compared to preoperative status.

CONCLUSION

This study showed a significant deficit of randomized control trials treated with osteotomies, in addition to TKA, and a lack of evidence-based surgical guidelines for the treatment of patients with OA in special conditions: posttraumatic deformities, stiff knee, severe varus, and valgus axis or patella disorders.

Posteromedial Corner Release with the Knee in Figure-of-Four Position vs Conventional Position for Varus Knee Arthroplasty

OBJECTIVE

To introduce posteromedial corner release with the knee in the figure-of-four position versus the conventional position for varus knee arthroplasty.

METHODS

This is a retrospective study. From March 2015 to September 2019, a series of 123 patients (139 knees) with varus knee were randomly and blindly allocated to experimental group (60 patients; 68 knees) and control group (57 patients; 65 knees). Patients in experimental group underwent posteromedial corner release with the knee in the figure-of-four position; and patients in control group with the knee in the conventional position. If soft tissue balance was not completely achieved or the medial gap was still tight, an additional loosening technique were used to achieve symmetric medial and lateral space in both groups. Time for soft tissue balancing was defined as the time from the start of the spacer test to the end of the balance test. Length of release was defined as the distance from the osteotomy surface of the tibial plateau to the farthest structures released. The rating system of Hospital for Special Surgery (HSS) knee score was used to evaluate the clinical results. Quantitative variables were described as mean and standard deviation, and compared by one-way analysis of variance.

RESULTS

The mean age of experimental group and control group was 70.2 ± 8.7 years and 68.7 ± 6.2 years, respectively (P > 0.05). Preoperatively, the mean HSS score of the groups was 38.2 ± 11.3 and 39.1 ± 10.7, respectively (P > 0.05). The mean varus knee angle was 19.7° ± 9.3° and 19.3° ± 10.7°, respectively (P > 0.05). The mean time for soft tissue balancing was 8.4 ± 3.3 min and 11.3 ± 6.9 min in experimental and control group, respectively (P < 0.05). The mean length of releasing posteromedial corner structures was 35.5 ± 13.4 mm and 27.3 ± 9.7 mm in experimental and control group, respectively (P < 0.05). Additional special loosening techniques were performed in eight knees in experimental group and seven knees in control group. The HSS scores 5 years after surgery were 95.1 ± 16.9 and 94.8 ± 17.2 respectively (P > 0.05). No complications were found during the follow-up time, and the clinical symptoms were observed to be significantly improved in the patients.

CONCLUSION

The posteromedial corner can be released more extensively and thoroughly when the knee is placed in the figure-of-four position during varus knee arthroplasty.

Catastrophic tibial baseplate failure of a modern cementless total knee arthroplasty implant

Tibial baseplate fracture following primary total knee arthroplasty is a rare complication, particularly with modern implants and surgical techniques. This case details the first known report of mid-range follow-up catastrophic failure of a cementless modular, trabecular metal tibial baseplate. This failure highlights the importance of continued follow-up for novel implants, to include cementless knee arthroplasty designs, particularly if new symptoms arise or periarticular bone loss is identified on radiograph.

Selective medial soft tissue release combined with tibial reduction osteotomy in total knee arthroplasty

BACKGROUND

To obtain the correct coronal alignment and balancing in flexion and extension, we established a selective medial release technique and investigated the effectiveness and safety of the technique during primary total knee arthroplasty (TKA).

METHODS

Four hundred sixty-six primary TKAs with varus deformity were prospectively evaluated between June 2013 and June 2015. A knee joint position similar to Patrick's sign was used to release the medial structure. The medial release technique consisted of release of the capsule and the deep medial collateral ligament (dMCL) (step1), selective release of superficial medial collateral ligament (sMCL) or posterior oblique ligament (POL) (step 2), and selective tibial reduction osteotomy (step 3). Improvement of medial joint gap at each step and other clinical outcomes were evaluated.

RESULTS

Among the 466 knees, symmetrical gaps could be achieved by the limited release of the capsule and the dMCcL in 276 (59%) knees. One hundred fifty-two (33%) required additional sMCL release with 2-5 cm from the joint line distally or POL release. Thirty-eight (8%) necessitated an additional tibial reduction osteotomy. Anterior-medial release and 4-mm medial osteotomy contributed to more improvement of medial gap in flexion than in extension (each p < 0.01). Posteromedial release and posteromedial osteotomy contributed to more improvement in extension than in flexion (each p < 0.01). No specific complication related to our technique was identified.

CONCLUSION

The technique of the tibial reduction osteotomy combined with medial soft structure release using Patrick's sign is effective, safe, and minimally invasive to obtain balanced mediolateral and extension-flexion gaps in primary TKA.

Mechanically aligned total knee arthroplasty carries a risk of bony gap changes and flexion-extension axis displacement

PURPOSE

The flexion-extension axis (FEA) of the femur is substantially changed after mechanically aligned total knee arthroplasty (TKA) due to a discrepancy in bone cut thickness between the posterior and distal femoral regions. This study assessed the bony gap changes and FEA displacement caused by this problem in osteoarthritis patients.

METHODS

The study enrolled 60 knees from 60 patients for whom primary TKA was planned due to medial knee osteoarthritis. All patients underwent computed tomography, and 3-dimensional (3D) bone models were reconstructed on 3D-planning software. Bone cuts of the distal femur and proximal tibia were simulated to be perpendicular to each mechanical axis. Bony gap change was computed as the difference in bone cut thickness between medial and lateral compartments. Each femoral condyle was assessed for potential FEA displacement, as the difference in bone cut thickness between posterior and distal femoral regions.

RESULTS

The mean magnitude of bony gap discrepancy necessary for mediolateral balancing was 1.6 ± 3.3 mm (range -7 to 8.2 mm) at 0° extension and -0.2 ± 2.6 mm (range -6.4 to 4.3 mm) at 90° flexion. At least 2 mm of bony gap discrepancy at 0° extension and 90° flexion was found in 40 patients (67%) and 26 patients (43%), respectively. In terms of femoral bone cut, posterior bone cut thickness was significantly larger than distal bone cut thickness in the medial compartment (p < 0.001). Bony gap discrepancy between distal and posterior regions of the femoral condyle was ≥2 mm in 28 patients (47%).

CONCLUSIONS

This study focused on two flaws of mechanically aligned TKA in OA patients. Substantial numbers of patients inevitably required >2 mm of medial collateral ligament release at 0° extension and showed a bone cut discrepancy between distal and posterior regions, carrying a risk of FEA displacement and subsequent unnatural knee motions during knee extension and flexion. Level of evidence IV.

Reduction Osteotomy versus Extensive Release on Clinical Outcome Measures in Simultaneous Bilateral Total Knee Arthroplasty

Background

During total knee arthroplasty (TKA) in varus knee deformities, reduction osteotomy (RO) and medial soft tissue release are alternative techniques to aid in achieving deformity correction. In this study, we investigated the effect of RO compared to extensive medial soft tissue release (ER) on clinical outcome measures in simultaneous bilateral TKA.

Material/Methods

We prospectively enrolled 24 patients (48 knees) with bilateral varus knee deformity from July 2014 to December 20l5. For each patient, one knee was assigned to the RO group and the contralateral knee was assigned to ER group. One year postoperative, follow-up outcomes were collected and analyzed.

Results

Time to 90° flexion of the knee was significantly different in the RO group (1.6±0.3 days) compared to the ER group (2.0±0.4 days) (p<0.001). Using a 10-item patient reported outcome questionnaire, total scores were significantly different between the RO group (86.3±3.2) and the ER group (82.4±2.7) (p<0.001). Analysis of variance showed a significant difference on the visual analogue scale (VAS) score (p<0.001) but no significant difference in the range of motion (ROM) of the knee (p>0.05) during the follow-up year.

Conclusions

Knees treated with RO were associated with greater improvements in pain and function than knees treated with conventional ER technique. Additionally, RO technique did not confer an increased risk for adverse clinical outcomes. RO may therefore by a safe method to decrease postoperative pain, achieve earlier functional recovery, and increase patients’ subjective satisfaction after TKA.

What Preoperative Radiographic Parameters Are Associated With Increased Medial Release in Total Knee Arthroplasty?

BACKGROUND

Preoperative varus deformity of the knee is a common malalignment in patients undergoing primary total knee arthroplasty (TKA). We are unaware of any studies that have correlated how various preoperative radiographic parameters can predict the amount of medial releases performed to achieve optimal coronal alignment and ligamentous balance.

METHODS

A retrospective review was performed on 67 patients who required at least a medial tibial reduction osteotomy (MTRO) during primary TKA to achieve coronal balance. This patient population was matched 1:1 to another cohort of TKA patients by age, gender, and body mass index who did not require an MTRO. A radiographic evaluation was used to compare the 2 cohorts.

RESULTS

Preoperatively, the MTRO cohort was noted to have significantly increased varus tibiofemoral (86.12° vs 93.43°), tibial articular surface (85.79° vs 87.54°), and medial tibial articular surface angles (75.22° vs 85.34°) compared to the control cohort. The MTRO cohort had 3.13 mm of medial tibial offset and 9.06 mm of lateral joint space opening and the control cohort had 0.09 mm and 4.07 mm, respectively. The medial tibial articular surface angle and lateral joint space widening were statistically associated with the MTRO cohort. The final tibiofemoral angle in the MTRO cohort was 92.43° and was 93.40° in the control cohort.

CONCLUSION

The MTRO cohort was noted to have several preoperative radiographic parameters that were significantly different than the control cohort. However, the medial tibial articular surface angle and lateral joint space widening were the only radiographic parameters that were statistically associated with requiring an MTRO.

Reduction Osteotomy vs Pie-Crust Technique as Possible Alternatives for Medial Release in Total Knee Arthroplasty and Compared in a Prospective Randomized Controlled Trial

BACKGROUND

To compare the gap change between the pie-crust technique and reduction osteotomy to determine their effects on flexion and extension gaps and their success rates in achieving ligament balancing during total knee arthroplasty.

METHODS

In a prospective randomized controlled trial, 106 total knee arthroplasties were allocated to each group with 53 cases. If there was a narrow medial gap with an imbalance of ≥3 mm after the initial limited medial release, either reduction osteotomy or pie-crust technique was performed. The changes of extension and flexion medial gaps along with the success rate of mediolateral balancing were compared.

RESULTS

There was a significant difference in the change of medial gap in knee extension with mean changes of 3.5 ± 0.5 mm and 2.3 ± 0.8 mm in the reduction osteotomy and pie-crust groups, respectively (P < .001). For flexion gap, greater change was found in the pie-crust group compared with the reduction osteotomy group; the mean medial gap changes in knee flexion were 1.1 ± 0.5 mm and 2.3 ± 1.2 mm in the reduction osteotomy and pie-crust groups, respectively. The success rates were 90.6% and 67.9% in reduction osteotomy and pie-crust groups, respectively (P = .007).

CONCLUSION

As an alternative medial release method, reduction osteotomy was more effective in extension gap balancing, and pie-crust technique was more effective in flexion gap balancing. The overall success rate of mediolateral ligament balancing was higher in the reduction osteotomy group than in the pie-crust group.