Associations between gait analysis parameters and patient satisfaction one year following primary total knee arthroplasty

BackgroundThe purpose of this prospective study was to understand the relation between gait outcomes and patient satisfaction one year after total knee arthroplasty (TKA).MethodsSeventy-nine patients were evaluated before and one year after TKA using clinical gait analysis. Specific gait outcomes were analyzed: gait speed, stance phase, range of motion (ROM) knee flexion and maximal knee flexion. The parameters of interest selected for the statistical analysis were: gait speed and maximal knee flexion during gait. The Western Ontario and MacMaster Osteoarthritis Index (WOMAC) and patient satisfaction were also assessed. The satisfaction was evaluated using a questionnaire and was splited in five categories: very unsatisfied, unsatisfied, neutral, satisfied or very satisfied. To assess associations between patient satisfaction and maximal knee flexion during gait and gait speed, an unadjusted ordinal logistic regression analysis was used. The analysis was then adjusted for covariates: age and Body Mass Index (BMI) before surgery and WOMAC pain one year after surgery.ResultsAll gait outcomes after TKA had significantly improved. The ordinal logistic regression analysis found significant associations between patient satisfaction and maximal knee flexion after TKA (unadjusted and adjusted) but not for gait speed.ConclusionThese findings show that all patients improved their gait outcomes one year after TKA but only a higher maximal knee flexion during gait may influence the level of patient satisfaction.     

Comparing in vivo kinematics of unicondylar and bi-unicondylar knee replacements

Preserving both cruciate ligaments in unicondylar knee arthroplasty likely provides more normal knee mechanics and contributes to enhanced patient function. It follows that preserving both cruciate ligaments with total knee arthroplasty should provide functional benefit compared to arthroplasty sacrificing one or both cruciates. The purpose of this study was to compare knee kinematics in patients with optimally functioning cruciate-preserving medial unicondylar and bi-unicondylar arthroplasty to determine if knee motions differed. Eight consenting patients with seven medial unicondylar and five bi-unicondylar arthroplasties were studied using lateral fluoroscopy during treadmill gait, stair stepping, and maximum flexion activities. Patient-specific geometric models based on CT and CAD data were used for shape matching to determine the three-dimensional knee kinematics. Tibiofemoral contact locations were computed for the replaced compartments. Maximum flexion in kneeling was 135°±14° for unicondylar knees and 123°±14° for bi-unicondylar knees (p=0.22). For 0°–30° flexion during the stair activity, the medial condyle translated posterior 3.5±2.5 mm in unicondylar knees and 4.7±1.9 mm in bi-unicondylar knees (p>0.05). Lateral posterior translation was 5.0±2.3 mm in bi-unicondylar knees for 0°–30° flexion. From heel-strike to mid-stance phase, there was little tibial rotation, but unicondylar knees showed 1.5±1.6 mm posterior translation of the medial condyle, while bi-unicondylar knees showed 5.1±2.2 mm (p<<0.05). The bi-unicondylar knees showed 3.8±3.4 mm posterior lateral condylar translation. Preserving both cruciate ligaments in knee arthroplasty appears to maintain some basic features of normal knee kinematics. Knees with bi-unicondylar arthroplasty showed kinematics closer to motions observed in total knee arthroplasty, slightly less weight-bearing flexion, and greater dynamic laxity in gait than unicondylar knees. Despite kinematic differences, knees with unicondylar and bi-unicondylar arthroplasty can provide excellent functional outcomes in appropriately selected patients.     

Quantitative evaluation of gait features after total knee arthroplasty: Comparison with age and sex-matched controls

BackgroundGait function after total knee arthroplasty (TKA) is suboptimal. However, quantified analysis with comparing a control group is lacking.Research questionThe aims of this study were 1) to compare the gait before and after TKA and 2) to compare postoperative gait to that of an age-sex matched control group.MethodsThis study consisted of 46 female and 38 male patients with end-stage knee osteoarthritis who underwent bilateral TKA, and 84 age- and sex-matched controls without knee pain and osteoarthritis. Seven gait parameters, including lower extremity alignment, knee adduction moment (KAM), knee flexion angle, external knee flexion moment, hip adduction angle, external hip adduction moment, and the varus-valgus arc during the stance phase, were collected using a commercial opto-electric gait analysis system. Principal component analysis was used for data processing and the standardized mean differences (SMDs) of the principal component scores were compared.ResultsThe most significant gait change after TKA was the alignment (SMD 1.62, p < 0.001). The average stance phase alignment changed from varus 7.3° to valgus 0.5°. The second significant change was a decrease of the KAM (SMD 1.08, p < 0.001). These two features were closely correlated (r = 0.644, p < 0.001). The gait feature that differed most from the controls was the varus-valgus arc during the stance phase (SMD 1.68, p < 0.001), which was constrained by 31% after TKA (p < 0.001) and was only 37% compared to the controls (p < 0.001).SignificanceImprovement in gait after TKA was obtained through alignment correction. However, TKA significantly constrained coronal knee motion. TKA improved gait suboptimally; the gait was significantly different from that of controls.     

Influence of intra-operative joint gap on post-operative flexion angle in osteoarthritis patients undergoing posterior-stabilized total knee arthroplasty

Recently, we developed a new tensor for total knee arthroplasty (TKA) procedures enabling soft tissue balance assessment throughout the range of motion while reproducing post-operative joint alignment with the patello-femoral (PF) joint reduced and the tibiofemoral joint aligned. Using the tensor with a computer-assisted navigation system, we investigated the relationship between various intra-operative joint gap values and their post-operative flexion angles. An increased value during the extension to flexion gap and a decreased value during the flexion to deep flexion gap with PF joint reduced, not everted, showed an inverse correlation with post-operative knee flexion angle, not pre-operative flexion angle. In conclusion, understanding the characteristics of joint gap kinematics in posterior-stabilized TKA under physiological and reproducible joint conditions may enable the prediction of the post-operative flexion angle and help to determine the appropriate intra-operative joint gap.     

Concurrent validity and inter trial reliability of a single inertial measurement unit for spatial-temporal gait parameter analysis in patients with recent total hip or total knee arthroplasty

BackgroundOsteoarthritis (OA) is one of the main causes of disability and its frequent hip and knee joint localization requires surgical joint replacement treatment. Patients after total hip (THA) or knee (TKA) arthroplasty often show gait abnormalities, whose comprehension is crucial in order to plan an appropriate rehabilitative treatment. Wearable sensor devices can be a valid tool for gait assessment in clinical practice, being relatively inexpensive and easy to use.Research questionDoes the use of crutches influence the ability of a single inertial measurement unit (IMU), placed on the lower trunk, to correctly record the spatial-temporal gait parameters in patients after recent THA or TKA?Methods20 patients walking with crutches after recent THA or TKA and 10 healthy subjects were recruited. Each participant was recorded simultaneously with an IMU and with an optoelectronic motion capture system during 5 consecutive walking tests.ResultsIntraclass correlation index of spatial-temporal parameters recorded with the IMU showed moderate to excellent reliability results both for healthy subjects (ICC range 0.626–0.897) and for patients (ICC range 0.596–0.951). In terms of concurrent validity, Pearson’s r coefficient of healthy subjects, showed strong to very strong levels of correlations for some spatial-temporal parameters (speed, mean cadence, left and right stride length and stride duration) (r range 0.646–0.977) and very week to moderately week levels of correlation for gait cycle phases (swing, stance, single support and double support) (r range 0.390–0.633). Patients’ data analysis showed similar results for general spatial-temporal parameters (r range 0.704–0.986) and slightly lower values for gait cycle phases (r range 0.077–0.464).SignificanceWe can consider the single IMU as a reliable tool for the detection of some spatial-temporal gait parameters. Crutches seem to interfere with the detection of the gait cycle phases.     

A soluble factor (EMMPRIN) in exudate influences knee motion after total arthroplasty

Few studies have been conducted to investigate biological factors that affect postoperative knee motion after total knee arthroplasty (TKA). The purpose of this study is to test the hypothesis that range of knee motion (ROM) at 4 weeks after TKA is correlated with the concentration of extracellular matrix metalloproteinase inducer (EMMPRIN) and transforming growth factor (TGF)-beta1 in the exudative fluid harvested from the joint after surgery. A prospective measurement study was conducted with 20 osteoarthritis patients who underwent TKA. At 48 h after surgery, the exudate was harvested from a closed drainage system. Enzyme-linked immunosorbent assay was performed to measure the concentration of TGF-beta1, EMMPRIN, MMP-1, 2, 9, tissue inhibitor of metalloproteinase-1, and Hyalunonan. Knee flexion angle was measured before and at 4 weeks after surgery. There was a significant correlation between the EMMPRIN levels and knee flexion angle (r = 0.557, p = 0.0148). Western blot analysis of the exudate showed a prominent band for EMMPRIN at 27 kDa. On the other hand, there was no correlation between the TGF-beta1 levels and the knee flexion angle. This study showed that EMMPRIN levels after TKA affect the postoperative ROM. As to clinical relevance, EMMPRIN in the exudate after TKA is a promising biological indicator to predict difficulty in restoring postoperative ROM.     

Patient function after a posterior stabilizing total knee arthroplasty: cam–post engagement and knee kinematics

Even though posterior substituting total knee arthroplasty has been widely used in surgery, how the cam–post mechanism (posterior substituting mechanism) affects knee joint kinematics and function in patients is not known. The objective of the present study was to investigate posterior femoral translation, internal tibial rotation, tibiofemoral contact, and cam–post engagement of total knee arthroplasty patients during in vivo weight-bearing flexion. Twenty-four knees with a PS TKA were investigated while performing a single leg weight-bearing lunge from full extension to maximum flexion as images were recorded using a dual fluoroscopic system. The in vivo knee position at each targeted flexion angle was reproduced using 3D TKA models and the fluoroscopic images. The kinematics of the knee was measured from the series of the total knee arthroplasty models. The cam–post engagement was determined when the surface model of the femoral cam overlapped with that of the tibial post. The mean maximum flexion angle for all the subjects was 112.5 ± 13.1°. The mean flexion angle where cam–post engagement was observed was 91.1 ± 10.9°. The femur moved anteriorly from 0° to 30° and posteriorly through the rest of the flexion range. The internal tibial rotation increased approximately 6° from full extension to 90° of flexion and decreased slightly with further flexion. Both the medial and lateral contact point moved posteriorly from 0° to 30°, remained relatively constant from 30° to 90°, and then moved further posterior from 90° to maximum flexion. The in vivo cam–post engagement corresponded to increased posterior translation and reduced internal tibial rotation at high flexion of the posterior substituting total knee arthroplasty. The initial cam–post engagement was also mildly correlated with the maximum flexion angle of the knee (R = 0.51, p = 0.019). A later cam–post engagement might indicate an environment conducive to greater flexion. If the factors that affect cam–post engagement timing can be established, proper manipulation of those factors may improve the function of the knee after posterior substituting total knee arthroplasty.     

Early results of high-flex total knee arthroplasty: comparison study at 1 year after surgery

We compared clinical [including maximal flexion and range of motion (ROM)] and radiographical outcomes of high-flex versus conventional implants for total knee arthroplasty (TKA) after 1 year. We also analyzed the factors affecting postoperative ROM in high-flex implants. The high-flex group (n = 90) had an average maximal flexion of 129.8° (standard deviation (SD), 5.2°) significantly higher than the 124.3° (SD, 9.2°) of the conventional group (n = 90), especially for patients with less than 90° of knee flexion (P < 0.05). There was no significant difference in hospital for special surgery (HSS) score between the two groups. No knee developed osteolysis, aseptic loosening, or other complications. We found that, for high-flex implants, preoperative ROM had a significant effect on postoperative ROM.     

Effect of improvement in quadriceps strength asymmetry on trunk movement asymmetry after total knee arthroplasty

BackgroundPatients with knee osteoarthritis (OA) demonstrate trunk movement asymmetry during walking; this asymmetry is associated with disability and quadriceps strength asymmetry.Research questionWhat are the differences between trunk movement asymmetries before and after total knee arthroplasty (TKA) and associations between the changes in trunk movement asymmetry and quadriceps strength asymmetry?MethodsIn this prospective cohort study, 27 patients (mean age, 71.0 years; women, 85.2%) were assessed at 1 month before and 6 months after surgery. Trunk movement asymmetry (harmonic ratio) was assessed at their preferred pace using a triaxial accelerometer. The isometric quadriceps strength was evaluated using a hand-held dynamometer, and the quadriceps strength inter-limb absolute difference was calculated. Multivariate analyses were performed to compare the trunk movement asymmetries before and after surgery with covariate adjustment (gait pain, gait velocity, and non-operated-limb Kellgren and Lawrence [K&L] grade) and to investigate the association between the changes in trunk movement asymmetry and quadriceps strength inter-limb difference with covariate adjustment (age, sex, and non-operated-limb K&L grade).ResultsThe trunk movement asymmetry in the medio-lateral (mean difference, 0.61; 95% confidence interval [CI], 0.22 to 1.00) and antero-posterior (mean difference, 1.15; 95% CI, 0.48 to 1.83) directions significantly decreased postoperatively compared with the preoperative results. A decreased quadriceps strength inter-limb difference was significantly associated with a decreased medio-lateral trunk movement asymmetry (β = 0.68; 95% CI, 0.30 to 1.06).SignificanceTKA plays an important role in the improvement of trunk stability during walking in patients with knee OA. Decreasing quadriceps strength asymmetry may be a key to improving trunk movement asymmetry.     

Comparing in vivo kinematics of anterior cruciate-retaining and posterior cruciate-retaining total knee arthroplasty

The purpose of this study was to compare knee kinematics in patients with bi-cruciate preserving total knee arthroplasty and posterior cruciate ligament (PCL) preserving total knee arthroplasty. Five knees received PCL-retaining arthroplasty and nine knees received both cruciate-retaining arthroplasty (ACL/PCL knees). We studied treadmill gait, stair stepping, and maximum flexion activities using lateral fluoroscopy and shape matching. For maximum flexion, the ACL/PCL knees showed 6 mm more posterior translation of the lateral condyle (p < 0.05). For the stair activity, posterior translations of the lateral condyle were significantly greater in the ACL/PCL knees from 30° to 70° flexion (p < 0.05). Both condyles in the ACL/PCL knees showed greater posterior translation in the stance and swing phases of gait than in the PCL knees (p < 0.05). Preserving both cruciate ligaments in total knee arthroplasty appears to maintain some basic features of normal knee kinematics in these activities.     

The influence of sex and pre-operative obesity on biomechanics two years after total knee arthroplasty: A longitudinal cohort study

BackgroundSex and obesity may influence knee biomechanics associated with poor outcomes following primary total knee arthroplasty (TKA) however their long-term impact has not been investigated.Research questionDoes sex and/or pre-operative obesity influence change in gait biomechanics from pre-TKA to two-years after TKA, and do knee biomechanics return to normal two-years after TKA?MethodsIn this longitudinal study, gait analysis was performed on 78 patients undergoing TKA for knee osteoarthritis prior to surgery (baseline), and on 66 (85 %) of these who returned at the two year follow-up. Gait biomechanics were also collected on a reference sample of 40 asymptomatic participants. Knee variables were analyzed according to time (pre- and post-TKA), sex (men and women), pre-operative obesity (obese vs non-obese), and group (TKA vs reference). Mixed linear regression models were used to examine the effects of TKA, obesity status, gender and all interactions.ResultsThere were two-year reductions in peak knee frontal plane angle (mean difference −7.21°; 95% confidence intervals −9.37 to −5.05), peak knee adduction moment (KAM) (-17.64Nm; −23.04 to −12.24) and KAM impulse (-9.40Nm.s; −12.04 to −6.77) in males. These and other variables were unchanged in women. At two years, men exhibited a greater varus-valgus thrust excursion (4.9°; 2.7–7.2), and a lower peak knee frontal plane angle (−4.4°; −7.1 to −1.7) and peak KAM (−13.1Nm; −20.9 to −5.4), compared to the reference sample. Biomechanics at two years did not differ between pre-operative obesity subgroups, or between female TKA patients and the reference sample.SignificanceChanges in gait biomechanics two years after TKA are influenced by sex but not obesity. Men but not women showed altered knee biomechanics two years following TKR and compared to a reference sample. It is unknown whether these altered biomechanics in men impact longer term clinical outcomes and satisfaction following surgery.     

Performance-based physical function correlates with walking speed and distance at 3 months post unilateral total knee arthroplasty

BackgroundAfter total knee arthroplasty (TKA), walking speed and distance are main concerns of patients.Research questionWhich physical functions affect walking speed and distance after TKA?MethodsCross-sectional data from 149 patients who underwent unilateral primary TKA and completed performance-based physical function tests. Instrumental gait evaluation for spatiotemporal parameters, isometric knee extensor and flexor strength of both knees, 6-minute walk test (6MWT), timed up-and-go (TUG) test, timed stair climbing test (SCT), and knee flexion and extension range of motion (ROM) of surgical knee were examined. Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) and EuroQol five dimensions (EQ-5D) questionnaires were also performed.ResultsUnivariate analyses revealed that post-operative walking speed showed significant positive correlations with cadence, stride length, propulsion index of surgical and non-surgical knee, peak torque (PT) of the extensor of surgical and non-surgical knee and flexor of surgical and non-surgical knee, 6MWT, EQ-5D, and significant negative correlations with gait cycle duration, TUG, SCT-ascent and descent, and WOMAC-pain scores. Post-operative walking distance had significant positive correlations with walking speed, cadence, stride length, swing phase duration, propulsion index of surgical and non-surgical knee, PT of the extensor of surgical and non-surgical knee, EQ-5D, and significant negative correlation with gait cycle duration, double support duration, TUG, SCT-ascent and descent. In the multivariate linear regression analyses, TUG, cadence, stride length and propulsion index of non-surgical knee were factor correlated with post-operative walking speed. The SCT-ascent and descent, TUG and propulsion index of surgical knee were factor correlated with post-operative walking distance.SignificancePhysical performance factors correlated with walking speed and distance at 3 months after surgery. Based on these observations, rehabilitation of bilateral muscle strength and functional mobility would be important for functional recovery after unilateral TKA.     

The contralateral knee may not be a valid control for biomechanical outcomes after unilateral total knee arthroplasty

BackgroundAlthough unilateral symptoms and unilateral total knee arthroplasty (TKA) are common, many patients have bilateral radiographic osteoarthritis (OA). Because the contralateral (non-operated) limb is often used as a comparison for clinical and biomechanical outcomes, it is important to know if the presence of OA influences movement patterns in either limb.Research questionThe purpose of this study was to compare bilateral sagittal plane biomechanics between subjects with and without contralateral knee OA after unilateral TKA.MethodsFifty-three subjects who underwent unilateral TKA underwent three-dimensional gait analysis 6–24 months after surgery participated in this cross-sectional study. Kellgren-Lawrence (KL) OA severity in the contralateral limb was measured, and subjects were classified into either a non-OA (KL 0 or 1) or OA (KL 2–4) group. Mixed-model ANOVA tests with factors of group and limb were used to compare biomechanical measures. In the presence of a significant interaction effect, post-hoc comparisons were performed.ResultsThe OA group had more knee flexion at initial contact, less knee flexion and extension excursions, and less knee extension in the contralateral limb compared to the non-OA group. The non-OA group had significant differences between limbs, with more knee flexion at initial contact, less knee joint excursion, and less peak knee extension on the operated limb compared to the contralateral limb, whereas there were no limb differences for the OA group. Kinetic variables were not different in the ANOVA models.Significance and interpretationSubjects with contralateral knee OA have more symmetrical gait, although they adopt a more abnormal and stiff-legged gait pattern bilaterally. Researchers and clinicians should consider radiographic disease severity, not just symptoms, in the contralateral limb when identifying appropriate subject samples for unilateral biomechanical studies. Symmetrical movement patterns between limbs after surgery should not be the sole factor upon which movement recovery is based.     

Rate of torque development is the primary contributor to quadriceps avoidance gait following total knee arthroplasty

BackgroundFollowing rehabilitation for total knee arthroplasty, “quadriceps avoidance gait”, defined by limited knee flexion angle excursion during walking, persists and contributes to poor long-term outcomes. Given the presence of several post-surgical impairments, identifying the contribution of multiple factors to knee flexion angle excursion is important to developing targeted interventions to improve recovery after total knee arthroplasty.Research questionsWhich outcomes continue to improve following rehabilitation for total knee arthroplasty? What are the primary contributors to impaired knee flexion angle excursion during walking following total knee arthroplasty?MethodsPeak muscle strength and rate of torque development of the quadriceps, hip abductors, and hip external rotators, five-time sit-to-stand test, Knee Injury & Osteoarthritis Outcome Score, and gait mechanics were assessed in 24 participants at three and six months post-surgery. Paired sample t-tests or Wilcoxon Signed-Rank tests were used to compare outcomes between assessments. Stepwise multiple linear regression were used to assess the contribution of each measure to knee flexion angle excursion.ResultsSignificant improvements were noted in all outcomes except hip external rotation rate of torque development, gait speed, and knee flexion angle excursion. Quadriceps rate of torque development and knee pain significantly contributed to knee flexion angle excursion at three months (Adjusted R² = 0.342), while quadriceps rate of torque development and peak hip external rotation strength significantly contributed at six months (Adjusted R² = 0.436).SignificanceWhile higher pain levels at three months and greater peak hip external rotation muscle strength at six months contribute to impaired knee flexion angle excursion, quadriceps rate of torque development was the primary contributor to knee flexion angle excursion at both three and six months after surgery. Implementing strategies to maximize quadriceps rate of torque development during rehabilitation may help to reduce quadriceps avoidance gait after total knee arthroplasty.     

人工全膝关节置换术治疗严重畸形膝关节临床研究

目的：探讨人工全膝关节置换术（total knee arthroplasty, TKA）治疗严重畸形膝关节的手术方法和临床疗效。方法对人工全膝关节置换术916例（1031膝）,严重畸形膝关节置换术80例,其中56例（70膝）成功随访。严重内翻畸形19例（23膝）、严重外翻畸形21例（27膝）、严重屈曲畸形16例（20膝）。术后平均随访时间60个月（6个月～10年）。对膝关节屈伸活动度、HSS、KSS膝关节评分系统对手术前后进行回顾性研究。结果膝关节屈伸活动度由术前平均80°（伸直0°～屈曲120°）提高到术后115°（伸直0°～屈曲130°）,膝关节评分系统 HSS、KSS术前及随访时比较差异有统计学意义（P＜0．05）,KSS评分：临床评分由术前平均33分（10～68分）提高到术后平均81分（70～100分）,HSS临床评分由术前平均43分（27～68分）提高到术后平均86分（72～100分）。膝内外翻、屈曲挛缩畸形得到较好矫正。结论严重畸形膝关节通过关节置换术同样能恢复正常的关节功能,提高了患者生活质量,获得满意的临床疗效。     

Knee biomechanics and contralateral knee osteoarthritis progression after total knee arthroplasty

BackgroundDespite the success rate of Total Knee Arthroplasty (TKA), many patients undergo contralateral TKA. It is possible that altered gait mechanics after unilateral TKA play a role in the progression of contralateral OA progression.Research questionThe purpose of this study was to identify biomechanical predictors of radiographic OA progression in the contralateral (non-surgical) knee after unilateral (primary/initial) TKA. In addition, this study quantified for patients who had contralateral OA progression.MethodsBiomechanical outcomes were collected 6–24 months after unilateral primary TKA and were used to predict changes in contralateral OA severity at follow-up. Participants were divided into “Progressor” and “Non-Progressor” groups based on changes in Kellgren-Lawrence (KL) OA grade and Joint Space Width (JSW) between baseline and follow-up testing sessions. Biomechanical factors during walking were peak knee adduction moment, knee flexion/extension excursions, knee angle at initial foot contact, and peak knee flexion/extension. Multiple independent t-tests were used to examine the magnitude of differences in biomechanical variables between the groups. Logistic regression was used to examine the association between the biomechanical predictors and change in KL scores and JSW.ResultsThe mean time between surgery and follow-up x-rays was 8.8 (2.4) years. Of 40 participants, 62.5–78% had contralateral radiographic knee OA progression by follow-up. There were no significant differences in the biomechanical variables between groups. For the regression analysis, none of the biomechanical variables were found to be predictors for contralateral OA progression.SignificanceAlthough abnormal biomechanics are known risk factors for primary knee OA, it is possible that the mechanisms that result in OA progression of the contralateral limb are different than primary knee OA progression. Future work should evaluate other objective measures of OA progression and determine if cumulative measures of joint loading are related to OA worsening.     

Partial restoration of knee kinematics in severe valgus deformity using the medial-pivot total knee arthroplasty

Purpose

The objectives of the study were to examine knee kinematics in knees with severe valgus deformities and to compare pre- and post-operative knee kinematics for the same subjects implanted with medial-pivot total knee arthroplasty (TKA).

Methods

Seven subjects with severe valgus deformities due to osteoarthritis (OA) or rheumatoid arthritis (RA) were enrolled in the prospective study. Prior to TKA, three-dimensional (3D) kinematics were assessed by 3D to 2D registration technique using the image matching software ‘Knee Motion’, under in vivo, weight-bearing conditions. Postoperatively, each subject again performed the same motion under fluoroscopic surveillance.

Results

Preoperative kinematics demonstrated external rotation of tibias from extension to flexion, and small posterior femoral translations dominated in the medial condyle associated with anterior slides during partial range of motion. Postoperatively, these non-physiological tibial rotations were restored, and most subjects exhibited small internal rotations of tibias. On average, preoperative tibial internal rotation was ?4.7° ± 7.6° from full extension to maximum flexion, and the angle was 4.8° ± 3.1° postoperatively (p = 0.01). In addition, small amounts of posterior translation of the lateral condyle and anterior translation of the medial condyle were confirmed in most subjects postoperatively.

Conclusions

The study showed that the preoperative kinematic pattern established in severe valgus deformity was different from the physiological knee pattern. In addition, post-operative results suggest that the non-physiological kinematics were partially restored after TKA by using the prosthesis design even in the absence of the posterior cruciate ligament (PCL) and the cam–post mechanism.

Level of evidence

II.     

Is it necessary to perform prehabilitation exercise for patients undergoing total knee arthroplasty: meta-analysis of randomized controlled trials

Objectives: This study was designed to test whether it is necessary to perform prehabilitation exercise for patients undergoing total knee arthroplasty (TKA).

Methods: Literatures were identified from Pubmed, Clinicaltrials, Cochrane library, and SpringerLink. All studies that compared a prehabilitation exercise group with control group before TKA were included. The primary outcome was length of hospital stay. Secondary outcomes were quadriceps strength and functional ability in short term (1.5 to 3 months) after TKA.

Results: There was significant difference in the length of hospital stay, knee range of motion (ROM) and sit-to-stand test (P＜0.05). No statistical differences were found in quadriceps strength, 6-minute walk, ROM, knee extension, knee flexion, WOMAC pain, WOMAC function, WOMAC stiffness between the two groups in short term after TKA (P＞0.05).

Conclusions: Our meta-analysis found that prehabilitation exercise was effective in reducing length of hospital stay. Importantly, it was an effective method for improving knee ROM and sit-to-stand test after TKA. However, there was no effect of prehabilitation exercise on the improvement of quadriceps strength, 6-minute walk, pain and functional recovery following TKA.     

Range of motion after total knee arthroplasty: the effect of a preoperative home exercise program

Purpose

Preoperative range of motion (ROM) is the most important variable to determine final flexion after total knee arthroplasty (TKA). The purpose of this study was to determine whether a preoperative home exercise program could improve ROM in the arthritic knee and whether this influenced ROM and functional recovery following primary TKA.

Methods

During the period between 2005 and 2006, one hundred and twenty-two patients with gonarthrosis were included in a prospective study and randomly allocated to either the control or the treatment group. The sixty-one subjects in the treatment group underwent a 6-week home-based exercise program before TKA surgery. All one hundred and twenty-two patients were assessed before and after this exercise intervention. Postoperative assessments were at 6 weeks, 6 months and 1 year. Each evaluation included knee ROM and the Knee Society Clinical Rating System. Length of hospital stay and postoperative duration before achieving 90° of knee flexion were also recorded.

Results

Exercise program improves knee motion in the presence of gonarthrosis. After TKA, the patients in the exercise group achieved 90° of knee flexion faster and had a shorter hospital stay. There is no prolonged effect on knee motion or patient function between 6 weeks and 1 year postoperatively.

Conclusion

Preoperative exercise of the arthritic knee facilitates immediate postoperative recovery following primary TKA.

Levels of evidence

Therapeutic study, Level I.