Active Flexion in Weight Bearing Better Correlates with Functional Outcomes of Total Knee Arthroplasty than Passive Flexion

Good Postoperative Flexion Angle Improves Knee Function and Improvement of Flexion Angle Increases Patient Satisfaction After Total Knee Arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) is a well-established procedure for treating knee joint diseases. However, the postoperative range of motion (ROM) varies and is an important indicator of TKA success. Recently, patient-reported outcome measures (PROMs) and patient satisfaction have drawn attention. However, the relationship between ROM and knee function obtained by PROM and satisfaction is not well understood.

METHODS

We retrospectively reviewed the data of 375 patients who underwent 500 primary TKA procedures. We measured the ROM before and after surgery. Knee joint function was evaluated using the Knee Injury Osteoarthritis Outcome Score, a PROM, and patients were classified into good function and poor function groups. Patient satisfaction was evaluated on a 5-graded scale as overall satisfaction, and patients were divided into a satisfied or a dissatisfied group according to the obtained scores. ROM was compared between the 2 groups, then significantly different factors were analyzed using multiple logistic regression analysis. Moreover, cut-off points of ROM for obtaining good function and patient satisfaction were determined using ROC curve analysis.

RESULTS

The postoperative flexion angle had a significant effect on knee function (P < .001). The cut-off value of the postoperative flexion angle for good knee function was 120°. The improvement in flexion angle had a significant effect on patient satisfaction (P = .004). The cut-off value for the improvement in the flexion angle was 5°.

CONCLUSION

The postoperative flexion angle had a significant effect on knee function and improvement in the flexion angle had a significant effect on patient satisfaction.

Weight-bearing knee flexion angle better correlates with patient-reported outcome measures than non-weight-bearing condition in total knee arthroplasty: a three-dimensional analysis study

Background

This study aims to elucidate and compare the relationship between the knee flexion angle and patient-reported outcome measures (PROM) in both non-weight-bearing (NWB) and weight-bearing (WB) conditions.

Methods

This retrospective cohort study included 61 knees (47 patients) who underwent total knee arthroplasty. The knee flexion angle was measured by three conditions: NWB in manual goniometer, NWB in fluoroscopic three-dimensional (3D) analysis and WB in the fluoroscopic 3D analysis. The PROM was evaluated by postoperative 2011 Knee Society Score (2011 KSS) and Knee injury and Osteoarthritis Outcome Score (KOOS). Correlations between the knee flexion angle and PROM was analyzed using Spearman’s correlation coefficient. Additionally, whether the angular difference between NWB and WB correlated with the PROM or not was evaluated.

Results

The NWB knee flexion angle in a goniometer, NWB in 3D analysis, and WB in 3D analysis were 124.6° ± 8.4°, 118.0° ± 10.5°, and 109.5° ± 13.3°, respectively. The angular difference was 8.5° ± 12.8°. No PROM correlation existed in NWB using a goniometer. Moreover, significant positive correlations in 2011 KSS symptoms (r = 0.35) and 2011 KSS functional activities (r = 0.27) were noted in NWB using 3D analysis. Significant positive correlations existed in 2011 KSS symptoms (r = 0.32), 2011 KSS functional activities (r = 0.57), KOOS pain (r = 0.37), KOOS activity of daily living (ADL; r = 0.45), KOOS sports (r = 0.42), and KOOS quality of life (r = 0.36) in WB using 3D analysis. Significant negative correlations were noted in 2011 KSS functional activities (r = − 0.45), KOOS ADL (r = − 0.30), and KOOS sports (r = − 0.38) in angular difference.

Conclusions

The WB knee flexion angle better correlated with PROM compared with NWB by evaluation of 3D analysis. The larger the angular difference existed between NWB and WB, the lower the PROM score.

No differences in knee kinematics between active and passive flexion-extension movement: an intra-operative kinematic analysis performed during total knee arthroplasty

Purpose

The objective of the present study was to acquire and compare by the use of a navigation system the intra-operative flexion-extension movement of the knee performed actively by the patient and passively by the surgeon before and after a total knee arthroplasty (TKA) implantation.

Methods

A cohort of 31 patients with primary knee osteoarthritis (OA), candidate for TKA underwent intra-operative kinematics assessment with a commercial navigation system before and after the definitive implant positioning of a Cruciate Retaining (CR) Mobile Bearing (MB) prostheses. The kinematical data were acquired while surgeon performed the flexion-extension movement (passive ROM - pROM), and while the patient performed it (active ROM - aROM). Differences between pre- and post- implantation and between active and passive motions, were statistically analyzed using paired Student t-tests (p = 0.05).

Results

No statistically significant difference were found between aROM and pROM with paired Student t-test regarding internal-external rotation and anterior-posterior translation of the femoral component with respect to the tibia during flexion-extension movement before and after TKA implant (p > 0.05).

Conclusions

Active muscle contraction seems to not significantly affect TKA kinematics. The ROM performed by the surgeon during operation resemble the movement actively performed by the patient.

The clinical relevance of this study further supports the use of CAS system in performing intra-operative analysis concerning knee biomechanics.

Static progressive stretch orthosis-consensus modality to treat knee stiffness-rationale and literature review

The current literature supports static progressive stretch (SPS) orthoses as the consensus modality to treat joint stiffness as an adjunct to manual therapy. Over 50 published studies prove the efficacy and safety of this modality as an adjunct to therapy to improve range of motion (ROM) as well as decrease stiffness and pain. Data from a large prospective study on SPS effectiveness identified a 90% improvement in ROM, 84% reduction in stiffness and swelling, 70% reduction in pain, and no reports of complications or injury. Another 13 studies evaluating patients with knee stiffness have shown excellent results with SPS, and a reduced need for manipulation under anesthesia or additional surgeries. The bidirectional SPS device allows for ROM therapy in both flexion and extension, uses short, 5-minute incremental stretches for up to a 30-minute session applied 1 to 3 times per day for 8 weeks, though treatment might be needed for longer durations (8 to 12 weeks) in cases with chronic stiffness/contracture, to improve motion and significantly reduces need for manipulation or surgery for treatment of knee fibrosis. Earlier application of SPS therapy, even immediately postoperative following corrective surgery for motion loss, can greatly improve the results for patients who have limitations in knee motion.

Gradual change in knee extension following total knee arthroplasty using ultracongruent inserts

BACKGROUND

Total knee arthroplasty (TKA) using an ultracongruent (UC) insert is widely performed. Lack of the posterior cruciate ligament or post-cam mechanism is a concern in terms of range of motion. The flexion angle of UC TKA had been well investigated; however, natural history and correlation factors of the postoperative extension angle have not been well documented. This study aimed to investigate time-dependent changes in extension after TKA using UC inserts, and to evaluate factors that correlated with the postoperative extension angle.

METHODS

This study reviewed 388 gap-balanced UC TKAs (331 patients) without hyperextension at navigation and performed between November 2010 and December 2014. The extension angle (a positive number indicates hyperextension) was measured on full-extension lateral radiographs. The extension angles from five days post-operation to final follow-up were investigated. Factors correlated with the postoperative extension angle were evaluated using multiple regression analysis.

RESULTS

Mean follow-up duration was 46.2 months. Until two years, the extension angle gradually increased; mean angles at five days/six months/one year/two years/and final follow-up were: -9.2°/-2.6°/0.6°/1.0°/1.0°, respectively. Female sex (β = -0.15, P = 0.002) and pre-operative hyperextension (β = 0.31, P < 0.001) were associated with postoperative hyperextension deformity.

CONCLUSIONS

Following UC TKA, knees became gradually more extended until two years post-operation. Sex and pre-operative extension angle were predictive factors for the postoperative extension angle following UC TKA.

LEVEL OF EVIDENCE

Level 4, Case series.

Does the severity or cause of preoperative stiffness affect the clinical results and range of motion after total knee arthroplasty?

The purpose of this study was to assess the overall clinical results and range of motion (ROM) after total knee arthroplasty (TKA) in patients with preoperative stiffness. We also aimed to determine whether the severity or cause of the stiffness can affect the clinical outcome after surgery. This retrospective study included 122 knees (117 patients) with follow-up of more than 2 years (mean age, 64.3 years). TKA was performed using posterior-stabilized, varus-valgus constrained (VVC), and hinged prostheses. To determine the effect of the severity of stiffness on the clinical outcome, the subjects were divided into two groups: the severe group (preoperative ROM ≤ 50°; 18 knees) and the moderate group (preoperative ROM, 50°–90°; 104 knees). Then, clinical results and ROM were compared according to the severity or cause of preoperative stiffness. After surgery, preoperative ROM (mean, 78°; range, 25°- 90°) was improved (mean, 107°; range, 70°- 130°). The severe group more frequently used the VVC or hinged prostheses (72% vs. 18%). Furthermore, the severe group had worse knee and function scores as well as more complications (33% vs. 13%), even though the severe group had a greater ROM increment (47° vs. 27°) after surgery. Patients with osteoarthritis and rheumatoid arthritis showed better ROM and clinical results compared to patients with infectious or traumatic arthritis. Although TKA in stiff knees can be successful, the results are inferior in knees with severe stiffness and knees with infectious or traumatic arthritis.