Does knee alignment influence gait in patients with severe knee osteoarthritis?

Background

Patients with knee osteoarthritis present an altered gait pattern. Amongst many factors, the lower limb alignment (varus, valgus) has been identified as an important risk factor for the progression of knee osteoarthritis. Among the large number of studies on knee osteoarthritis gait, only a few have included patients with a valgus deformity. The aims of this study were to determine how knee alignment influences full-body gait in patients with knee osteoarthritis and if knee malalignment is associated with pain and functional capacity.

Methods

Sixty patients with severe knee osteoarthritis scheduled for a total knee arthroplasty were included in this study. Twenty-six subjects were recruited as the control group. The spatio-temporal parameters, three-dimensional full-body kinematics, and lower body kinetics were evaluated during a comfortable gait and compared between the groups. Pain and function were assessed with the WOMAC questionnaire.

Findings

The full-body gait analysis demonstrated substantially different gait patterns and compensation mechanisms between the three groups. Patients with varus knee alignment significantly augmented their trunk movements in sagittal and frontal planes compared to patients with a valgus knee. In addition, patients with a valgus knee reported lower pain and lower functional deficits compared to patients with a varus knee.

Interpretation

We found that gait compensations were significantly influenced by lower limb alignment. These new insights related to different knee osteoarthritis gait patterns might help in the understanding of gait compensation behaviours prior to total knee arthroplasty and better manage the strategies of rehabilitation following surgery.     

Impact of postoperative functional exercise on recovery of knee joint followin g knee arthroscopic meniscectomy

INTRODUCTIONItiswellknownthatsemilunarplateiscapableofconductingload，absorbingconcussion，stablilizingkneejoit．Semilunarplatecanconduct４０％－６０％ofload，increasecontactarea，andreducepressureenduredbycartilageofkneejoint．MATERIALSANDMETHODSMaterialsFromJune１９９６toDecember２０００，７８patientswitharthroscopeconfirmedsemilunarplateinjuryandundergonemeniscectomyun－derkneearthroscopeparticipatedourstudy．Thesepatientsincluded３０menand４８womenaged１２－５８years（meanage…     

Wear of contemporary total knee replacements – A knee simulator study of six current designs

Background

Compared to conventional ultra-high molecular weight polyethylene (UHMWPE), crosslinked polyethylene showed significantly reduced wear rate in hip simulation and early prospective-randomized clinical studies. The crosslinking process can reduce the mechanical properties of UHMWPE, particularly the fatigue strength. UHMWPE fatigue occurs more frequently in the knee joint than in the hip joint due to its higher contact stresses and there is therefore an increased concern of mechanical failure. Therefore, the purpose of this study was to determine the wear behaviour and the wear rates of different current knee designs and bearing materials.

Methods

In a knee-joint-simulator four kinds of crosslinked polyethylene (one produced by sequential irradiation and annealing process, three by different remelting processes, including fixed- and mobile-bearing-types) and two UHMWPE- (fixed- and mobile-bearing) inserts were tested with the appropriate femoral and tibial component recommended from the manufacturer.

Findings

All types of crosslinked polyethylene produced statistically significant (P < 0.05) lower wear rates than the conventional UHMWPEs without any traces of fatigue. There were no differences in the wear rates between fixed-and mobile-bearings (crosslinked polyethylenes and UHMWPEs; P > 0.05). The crosslinked polyethylene tibial inserts manufactured by sequential irradiation and annealing (X3™) combined with the Scorpio^®-knee-design had the lowest wear rates (P < 0.05) overall.

Interpretation

Fixed- as well as mobile-bearing crosslinked polyethylene tibial inserts are suitable for total knee arthroplasty and showed reduced wear rates compared with conventional UHMWPE. The combination of the fixed-bearing Scorpio^®-knee-design with a sequential irradiated and annealed crosslinked polyethylene tibial insert (X3™) seems to have an advantage in wear generation compared with other fixed- and mobile-bearing knee designs.     

Individuals’ experience of living with osteoarthritis of the knee and perceptions of total knee arthroplasty

This study investigated the physical and psychosocial consequences of living with osteoarthritis (OA) in daily life and peoples’ views of total knee arthroplasty (TKA) and the role of physiotherapy. In-depth interview data were used from a prospective qualitative study conducted by the senior author (KY). Participants were 15 volunteers with knee OA who were awaiting TKA at a specialized orthopaedic tertiary care facility in Toronto. A modified grounded theory method approach was used to analyze the interview data. The findings showed that experiences for the participants with OA were conceptualized as a “breakpoint.” The breakpoint was centred on the experiences/processes of living with unremitting pain, the limitations of mobility, leisure and social activities, and the resulting consequences to the participant's physical and psychological well-being. In addition to the above experiences, participants also discussed their perceptions of TKA surgery. The findings showed that expectations of TKA were linked to participants’ knowledge of the procedure and its outcomes. The participants listed acquaintances, friends, family members, and doctors as the main sources of knowledge for TKA. On the basis of the above analysis, recommendations are made for developing a preoperative physiotherapy program that would focus on minimizing preoperative disability and maximizing postoperative recovery.     

Recovery after functional exercises following arthroscopic debridement of knee joint in elderly persons with osteoarthritis of knee joint

INTRODUCTIONInrecentyears,arthroscopehasbecomeanewapproachfortreatmentofosteoarthritisofkneejoint.Weobtainedfavorableeffectofarthroscopicarticulardebridementinpatientswithbonyarthropathyofkneejoint.MATERIALSANDMETHODSMaterials104elderlypatientswithosteoarthritisofkneejointreceivedarthro-scopicdebridementfromJune1993toJune1998.Thesepatientsin-cluded41menand63women,agingfrom48-82years(meanage:61.3years).47hadlesioninleftknee,55inrightknee,2hadbilaterallesions,total106affectedknees.…     

Is latero-medial patellar mobility related to the range of motion of the knee joint after total knee arthroplasty?

Diminished range of motion (ROM) of the knee joint after total knee arthroplasty (TKA) is thought to be related to reduced patellar mobility. This has not been confirmed clinically due to a lack of quantitative methods adequate for measuring patellar mobility. We investigated the relationship between patellar mobility by a reported quantitative method and knee joint ROM after TKA. Forty-nine patients [osteoarthritis – OA: 29 knees; rheumatoid arthritis – RA: 20 knees] were examined after TKA. Respective medial and lateral patellar mobility was measured 1 and 6 months postoperatively using a patellofemoral arthrometer (PFA). Knee joint ROM was also measured in each of those 2 sessions. Although the flexion and extension of the knee joints improved significantly from 1 to 6 months after TKA, the medial and lateral patellar displacements (LPDs) failed to improve during that same period. Moreover, only the changes in knee flexion and medial patellar displacement (MPD) between the two sessions were positively correlated (r = 0.31, p < 0.05). However, our findings demonstrated that medial and lateral patellar mobility had no sufficient longitudinal relationship with knee ROM after TKA.     

Is discharge knee range of motion a useful and relevant clinical indicator after total knee replacement? Part 1

Objectives Knee range of motion (ROM) at the point of discharge from acute care is used as a clinical indicator to benchmark performance between hospital services after total knee replacement (TKR). The utility of the current benchmark, including whether discharge ROM varies between hospitals, is unknown. This study aimed to determine whether the benchmark [≥80 degrees flexion and ≤5 degrees fixed flexion (extension)] is realistic and whether the service provider is a predictor of knee ROM. Methods A prospective, observational cohort study was conducted involving 176 TKR patients from four hospitals. Knee ROM was photographically assessed preoperatively and at discharge. ‘Hospital’, typical patient demographic data and preoperative ROM were identified a priori as potential predictors of knee ROM. Results Overall, 2% [95% CI (confidence interval) 1–6] of patients attained the ROM benchmark. Individual hospital attainment of the benchmark ranged 0–7% with a significant difference (P = 0.047) evident between the best performer and the remaining hospitals. The overall rates of attainment of the individual flexion (25%, 95% CI 19–32) and extension (15%, 95% CI 10–21) components were similarly low, although the scatter between hospitals was large [flexion (2–47%); extension (8–44%)]. Preoperative flexion and hospital were significant (P = 0.002) predictors of discharge flexion, explaining 21% of the variance. Similarly, hospital and preoperative extension together with gender were significant (P < 0.001) predictors of discharge extension, explaining 26% of the variance. Conclusions A small minority of patients attained the knee ROM benchmark, indicating the existing standard is unrealistic. Nevertheless, that ‘hospital’ is an important predictor confirms the potential of ROM for benchmarking purposes. Differences in physiotherapy practices may contribute to inter‐hospital variation in discharge knee ROM together with other undefined factors. The causal relationships explaining the variation and the relationship between discharge ROM and longer‐term outcome are avenues for future exploration which will help define the clinical relevance of the indicator.     

Reliability of knee joint range of motion and circumference measurements after total knee arthroplasty: does tester experience matter?

Background and Purpose. Two of the most utilized outcome measures to assess knee joint range of motion (ROM) and intra‐articular effusion are goniometry and circumference, respectively. Neither goniometry nor circumference of the knee joint have been examined for both intra‐tester and inter‐tester in patients with total knee arthroplasty (TKA). The purpose of this study was to determine the intra‐tester and inter‐tester reliability of active and passive knee joint ROM and circumference in patients with TKA when administered by physiotherapists (testers) with different clinical experience. Method. The design was an intra‐tester, inter‐tester and intra‐day reliability study. Nineteen outpatients (10 females) having received a TKA were examined by an inexperienced and an experienced physiotherapist. Following a standardized protocol, active and passive knee joint ROM and circumference measurements were obtained using a universal goniometer and a tape measure, respectively. To establish reliability, intraclass correlation coefficients (ICC_2,1) and smallest real difference (SRD) were calculated. Results. The knee joint ROM and circumference measurements were generally reliable (ICC > 0.8) within and between physiotherapists (except passive knee extension). Changes in knee joint ROM of more than 6.6° and 10° (except active knee flexion) and knee joint circumference of more than 1.0 cm and 1.63 cm represent a real clinical improvement (SRD) or deterioration for a single individual within and between physiotherapists, respectively. Generally, the experienced tester recorded larger knee joint ROM and lower circumference values than that of the inexperienced tester. Conclusions. In clinical practice, we suggest that repeated knee goniometric and circumferential measurements should be recorded by the same physiotherapist in individual patients with TKA. Tester experience appears not to influence the degree of reliability. Copyright © 2009 John Wiley & Sons, Ltd.     

Redistribution of knee stress using laterally wedged insole intervention: Finite element analysis of knee–ankle–foot complex

Background

Laterally wedged insoles are widely applied in the conservative treatment for medial knee osteoarthritis. Experimental studies have been conducted to understand the effectiveness of such an orthotic intervention. However, the information was limited to the joint external loading such as knee adduction moment. The internal stress distribution is difficult to be obtained from in vivo experiment alone. Thus, a three-dimensional finite element model of the human knee–ankle–foot complex, together with orthosis, was developed in this study and used to investigate the redistribution of knee stress using laterally wedged insole intervention.

Methods

Laterally wedged insoles with wedge angles of 0, 5, and 10° were fabricated for intervention. The subject-specific geometry of the lower extremity with details was characterized in the reconstruction of MR images. Motion analysis data and muscle forces were input to drive the model. The established finite element model was employed to investigate the loading responses of tibiofemoral articulation in three wedge angle conditions during simulated walking stance phase.

Findings

With either of the 5° or 10° laterally wedged insole, significant decreases in von Mises stress and contact force at the medial femur cartilage region and the medial meniscus were predicted comparing with the 0° insole.

Interpretation

The diminished stress and contact force at the medial compartment of the knee joint demonstrate the immediate effect of the laterally wedged insoles. The intervention may contribute to medial knee osteoarthritis rehabilitation.     

Prevention and rehabilitation of knee joint injury in sports

BACKGROUND：Themainmanifestationofkneejointinjuryistheinjuryofmeniscusandrelativeligament．Themicrotraumatictechniqueofarthroscopecouldbeappliedtomostofthekneejointinjurypatients，however，therehabilitationmeasureisalsoneces－saryforfunctionalrecovery．OBJECTIVE：Todiscusstheeffectofrehabilitationexerciseforpatientswithkneejointinjuryinsports．UNIT：DepartmentofOrthopaedics，GuangzhouGeneralHos－pitalofGuangzhouMilitaryRegionSUBJECTS：Therewere３８９patientswithkneejointinjuryi…     

Fixed and mobile bearing total knee arthroplasty – Influence on wear generation,corresponding wear areas,knee kinematics and particle composition

Background

Several studies in literature are dealing with a direct comparison between fixed and mobile bearing knee replacements, but to our knowledge there is no published data comparing the wear behaviour of the two design principles based on the same femur and superior gliding surface geometry. The objective of our study was to investigate a fixed and mobile bearing knee design with identical femoral articulation in regard to wear, tibio-femoral kinematics and particle size distribution.

Methods

In vitro wear simulation according to ISO 14243-1 has been performed with the Columbus^® knee system (Aesculap, Tuttlingen) in the configurations fixed and mobile bearing for five million cycles on a customized four station knee wear simulator. The tests were running under force control and the tibio-femoral kinematics were assessed. A particle analysis has been undergone after each inspection interval when the lubricant was replaced.

Findings

Due to the additional wear in the tibial articulation of the mobile bearing design the mean gravimetric wear rates are not statistically different between the two groups. Apart of that there is a substantial reduction in the amount of wear per area unit for the mobile versus the fixed bearing gliding surfaces. Both groups show comparable tibio-femoral kinematics and a similar wear debris morphology.

Interpretation

Our investigation of a fixed and mobile bearing knee design with identical femoral articulation demonstrates that there are no significant differences in wear rate, resulting kinematics and polyethylene particle release. Therefore it can be recommended that surgeons decision for one or the other design principle should be based on the individual patient profile.