Measured flexion following total knee arthroplasty

Exploring the Impact and Acceptance of Wearable Sensor Technology for Pre- and Postoperative Rehabilitation in Knee Replacement Patients: A U.K.-Based Pilot Study

Knee replacement operations are common, highly successful procedures that are increasing in frequency. The COVID-19 pandemic has emphasized the need for innovative care pathways that reduce face-to-face appointments. We report on the impact of introducing a wearable sensor for pre- and postoperative rehabilitation of 21 knee replacement patients at 2 hospitals in the U.K.

Characterizing the recovery trajectories of knee range of motion for one year after total knee replacement

Design: Retrospective analysis of routinely collected clinical data. Objective: This study modeled the recovery in knee flexion and extension range of motion (ROM) over 1 year after total knee replacement (TKR). Background: Recovery after TKR has been characterized for self-reported pain and functional status. Literature describing target knee ROM at different follow-up periods after TKR is scarce. Methods: Data were extracted for patients who had undergone TKR at a tertiary care hospital at 2, 8, 12, 26, and 52 weeks after TKR. A linear mixed-effects growth model was constructed that investigated the following covariates age, sex, pre-TKR range, body mass index, duration of symptoms, and their interaction with weeks post TKR. Results: Of the 559 patients included (age 64.8 ± 8.5 years), 370 were women and 189 were men. Knee ROM showed the greatest change during the first 12 weeks after TKR, plateauing by 26 weeks. For an average patient, knee flexion increased from approximately 100º 2 weeks post TKR to 117º 52 weeks post TKR. Knee extension increased from approximately 3º knee flexion 2 weeks post TKR to 1º flexion 52 weeks post TKR. Conclusions: The results showed that the maximum gains in knee ROM should be expected within the first 12 weeks with small changes occurring up to 26 weeks after TKR. In addition, age and presurgery knee ROM are associated with the gains in knee ROM and should be factored into the estimation of expected knee ROM at a given follow-up interval after TKR.

Is digital photography an accurate and precise method for measuring range of motion of the hip and knee?

BACKGROUND

Accurate measurements of knee and hip motion are required for management of musculoskeletal pathology. The purpose of this investigation was to compare three techniques for measuring motion at the hip and knee. The authors hypothesized that digital photography would be equivalent in accuracy and show higher precision compared to the other two techniques.

METHODS

Using infrared motion capture analysis as the reference standard, hip flexion/abduction/internal rotation/external rotation and knee flexion/extension were measured using visual estimation, goniometry, and photography on 10 fresh frozen cadavers. These measurements were performed by three physical therapists and three orthopaedic surgeons. Accuracy was defined by the difference from the reference standard, while precision was defined by the proportion of measurements within either 5° or 10°. Analysis of variance (ANOVA), t-tests, and chi-squared tests were used.

RESULTS

Although two statistically significant differences were found in measurement accuracy between the three techniques, neither of these differences met clinical significance (difference of 1.4° for hip abduction and 1.7° for the knee extension). Precision of measurements was significantly higher for digital photography than: (i) visual estimation for hip abduction and knee extension, and (ii) goniometry for knee extension only.

CONCLUSIONS

There was no clinically significant difference in measurement accuracy between the three techniques for hip and knee motion. Digital photography only showed higher precision for two joint motions (hip abduction and knee extension). Overall digital photography shows equivalent accuracy and near-equivalent precision to visual estimation and goniometry.

Meta-Analysis of Outcomes of a Single-Radius Versus Multi-Radius Femoral Design in Total Knee Arthroplasty

BACKGROUND

Although the single-radius (SR) femoral design is known to have theoretical advantages in many aspects, studies of clinical outcomes that compare the SR with the multiple-radius (MR) femoral design are controversial. We performed a meta-analysis to address the hypothesis that a SR femoral design in primary total knee arthroplasty improves patient outcomes.

METHODS

The meta-analysis identified 15 articles reporting the clinical outcomes of 2212 knee replacements using the SR (n = 948) compared with the multiradius (MR; n = 1361) femoral design. Comparing SR with MR, we examined the Knee Society Score for the knee (KSS-knee), KSS-function, knee flexion, range of motion, complications, isometric peak torque of knee, and survival rate.

RESULTS

The range of motion of SR knees was lower than that of MR knees. No differences were found in the analyses of KSS-knee, KSS-function, knee flexion, complications, isometric peak torque of the knee, and survival rate.

CONCLUSION

Our meta-analysis does not provide clinical support for the previously reported theoretical advantages of the SR implant design.

Do patients really gain outcome benefits when using the high-flex knee prostheses in total knee arthroplasty? A meta-analysis of randomized controlled trials

The purpose of this study was to undertake a meta-analysis to evaluate whether patients really gain outcome benefits when using the high-flex (HF) prostheses in total knee arthroplasty (TKA) compared with standard (STD) implants. Only randomized controlled trials were included in this meta-analysis. After searching PubMed, Embase, Wed of Science and Cochrane Library, 1042 papers were identified and 18 trials were finally eligible for meta-analysis including 2069 knees (1906 patients). We found no statistically significant difference between the two designs in terms of ROM, knee scores (KSS, HSS, WOMAC, and SF-36), patients' satisfaction and complications. Hence there is currently no evidence to confirm that the use of high-flex prostheses in short-term is superior to the standard prostheses after total knee arthroplasty.

A comparison of stability and clinical outcomes in single-radius versus multi-radius femoral design for total knee arthroplasty

We compared the intraoperative varus-valgus stability from 0° to 90° of flexion and postoperative clinical outcomes in patients receiving TKA via either a single-radius femoral design (50 TKA, SR group) or multi-radius femoral design (50 TKA, MR group). We measured stabilities at 0°, 30°, 60° and 90° of flexion using a navigation system. The clinical outcomes including HSS scores, WOMAC scores and VAS score during stair climbing were compared after a minimum of 2-year follow-up. The single-radius femoral designs in TKA showed better intra-operative stability at 30° of flexion (7.6 vs. 8.3) compared with the multi-radius femoral design, but not at other angles. However, the clinical outcomes revealed no other significant differences in terms of HSS scores, WOMAC scores and VAS score between two groups.

Outcome and range of motion using a high-flexion cruciate-retaining TKA

Increased knee flexion after total knee arthroplasty (TKA) may contribute to patients' increased satisfaction and more active lifestyles. This study evaluated a TKA component designed for high flexion (more than 125°). The design features an anatomic sagittal femoral radius with short, flared femoral condyles to allow for femoral rollback. Fifty TKA procedures in 47 patients were evaluated prospectively regarding clinical outcomes using Knee Society knee and function scores, Short Form 12 physical component scores, and flexion measured clinically and by digital lateral supine active flexion radiographs. Preoperative and 1-year postoperative radiographs were analyzed by an independent observer. Mean maximum flexion measured clinically was 115° preoperatively and 120° one year postoperatively, with 76% of TKAs achieving more than 120° and 44% achieving more than 125°. Sex, body mass index, and preoperative flexion were not predictors of postoperative flexion. Mean flexion by radiograph was 108° preoperatively and 111° one year postoperatively, with 31% of knees achieving more than 120° and 14% more than 125°. Mean Knee Society knee and function scores and the Short Form 12 physical component scores were 52, 55, and 32 preoperatively, respectively, and 89, 77, and 40 one year postoperatively, respectively. Of the 50 knees, 84% had improvement in their Knee Society function scores, and 76% had improvement in their Short Form 12 physical component scores. The study revealed evidence of increased early postoperative flexion with the use of a cruciate-retaining high-flexion TKA design.