Clinical and radiologic evaluation of medial epicondylar osteotomy for varus total knee arthroplasty

Impacts of medial collateral ligament (MCL) stiffness adjustment on knee joint mechanics in mechanically aligned posterior-substituting (PS) total knee arthroplasty (TKA)

To investigate the biomechanical effects of medial collateral ligament (MCL) stiffness adjustments on knee kinematics-medial femoral rollback, femoral rotation, and joint contact forces-in mechanically aligned posterior-substituting (PS) total knee arthroplasty (TKA). A musculoskeletal model simulating squatting was developed using the AnyBody modeling system. A PS-TKA prosthesis was implanted, and MCL stiffness was modified in 20% increments. The effects on femoral rollback, femoral rotation, and joint forces were evaluated. Medial femoral rollback was not significantly affected by changes in MCL stiffness. However, when MCL stiffness exceeded 20% above normal, the pattern and magnitude of lateral femoral rollback were altered compared to other conditions. Increased MCL stiffness also altered internal-external femoral rotation and raised joint contact forces in the medial compartment. Muscle activity was largely unaffected by changes in MCL stiffness, although hamstring activity increased slightly during early flexion (0°-5°) when MCL stiffness exceeded 20%. Excessive MCL stiffness (over 20% above normal) affects lateral femoral rollback and increases joint contact forces, potentially elevating the risk of prosthetic wear. Maintaining MCL stiffness within physiological limits is critical for optimizing outcomes in varus knee TKA.

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.

Effect of mediolateral gap difference on postoperative outcomes in navigation-assisted total knee arthroplasty using an ultracongruent insert and the medial stabilising technique

PURPOSE

This study was aimed to compare the clinical, functional, and radiographic outcomes between symmetric and asymmetric extension and mediolateral gap balance after navigation-assisted (NA) total knee arthroplasty (TKA) using ultracongruent (UC) insets and the medial stabilising technique (MST).

METHODS

In all, 363 knees of 275 patients who underwent mechanical alignment-target NA TKA with MST between January 2015 and December 2017 were analysed. Patients were divided into balanced (extension mediolateral gap difference ≤ 2 mm) and tight medial (difference ≥ 3 mm) groups. Pre- and postoperative clinical, functional (range of motion, Western Ontario and McMaster University Osteoarthritis [WOMAC] index, Knee Society Knee Score [KSKS], and Knee Society Function Score [KSFS]) and radiographic (hip-knee-ankle [HKA] angle, femoral condylar offset, extension angle [a minus indicates hyperextension], and joint line distance) outcomes were compared between the groups. Student's t- or Chi-squared test was used to compare the outcomes.

RESULTS

Among the 363 knees analysed, 279 (77%) were assigned to the balanced group and 84 (23%) to the tight medial group. The preoperative HKA angle was significantly greater in the tight medial group than in the balanced group (9.7° ± 4.1° vs 14.3° ± 4.7°, P < 0.001). The postoperative WOMAC index, KSKS, and KSFS were similar between the groups. The change in the joint line distance was not significantly different (1.5 ± 3.7 vs 2.0 ± 3.3; n.s).

CONCLUSION

The clinical, functional, and radiographic outcomes, including joint line distance, were comparable between the tight medial and balanced group after mechanical alignment-targeted UC TKA with MST.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

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.

Medial femoral epicondyle upsliding osteotomy with posterior stabilized arthroplasty provided good clinical outcomes such as constrained arthroplasty in primary total knee arthroplasty with severe valgus deformity

PURPOSE

A modified technique referred to as a medial femoral epicondyle upsliding osteotomy was proposed to address severe valgus deformity with unconstrained posterior stabilized (PS) arthroplasty. The study compared the effectiveness of the technique and PS arthroplasty with constrained arthroplasty during primary total knee arthroplasty (TKA).

METHODS

Fifty-three patients presenting with valgus knees with a mean valgus angle (VA) greater than 30° were prospectively randomized and divided into two groups, and both groups received primary TKA. Upsliding osteotomy with PS arthroplasty was performed on the knees of 27 patients (group A), while the remaining 26 patients (group B) received a constrained arthroplasty. The Knee Society function score (KSF), Hospital for Special Surgery knee score (HSS), range of motion (ROM), mediolateral stability and hospitalization expenses were recorded. The hip-knee-ankle angle (HKA), femorotibial angle (FTA) and VA were analysed. Complications were also recorded.

RESULTS

The patients received follow-up care for more than 50 months. The postoperative KSF, HSS and ROM showed marked improvement in both groups (p < 0.05). Radiological assessments showed that HKA, FTA and VA for group A were restored to (179.9 ± 3.0)°, (173.0 ± 2.4)° and (7.0 ± 2.4)°, respectively. For group B, the HKA, FTA and VA were restored to (181.5 ± 2.3)°, (172.5 ± 2.3)° and (7.5 ± 2.3)°, respectively. Only two patients from group A demonstrated mild medial laxity in their knees, and the remaining patients from both groups were stable medially and laterally. However, the total hospitalization expenses and material expenses of group A were less than those of group B because of the more expensive constrained prosthesis and stems. No late-onset loosening or recurrent valgus deformity was displayed.

CONCLUSIONS

Both medial femoral epicondyle upsliding osteotomy with PS arthroplasty and constrained arthroplasty showed good outcomes for the restoration of neutral limb alignment and soft tissue balance, which are demonstrated to be safe and effective techniques for correcting severely valgus knees. Therefore, the clinically important finding of this study is that medial femoral epicondyle upsliding osteotomy with PS arthroplasty can be an alternative method for correcting severe valgus knees.

LEVEL OF EVIDENCE

II.