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Fulltext Iliotibial band tension reduces patellar lateral stability

Merican AM, Iranpour F, Amis AA

J Orthop Res, 2009 Mar;27(3):335-9.
PMID: 18925647 DOI: 10.1002/jor.20756

This study investigated the effect of loading the iliotibial band (ITB) on the stability of the patellofemoral joint. We measured the restraining force required to displace the patella 10 mm medially and laterally (defined as medial and lateral stability, respectively) in 14 fresh-frozen knees from 0 to 90 degrees knee flexion. The testing rig allowed the patella to rotate and translate freely during this displacement. The quadriceps was separated into five components and loaded with 175 N total tension. Testing was performed at 0 to 90 N ITB tension. With no ITB tension, the lateral restraining force ranged from 82 to 101 N across 0 to 90 degrees flexion. Increasing ITB tension caused progressive reduction of the lateral restraining force. The maximum reduction was 25% at 60 degrees flexion and 90 N ITB tension. Medial restraining force increased progressively with increasing knee flexion and increasing ITB loads; it ranged from 74 N at 0 degrees knee flexion and 0 N ITB tension to 211 N at 90 degrees knee flexion and 90 N ITB tension. The maximum effect was an increase of medial restraining force of 50% at 90 degrees flexion and 90 N ITB tension.

Matched MeSH terms: Joint Instability/physiopathology*
Biomechanical analysis of knee laxity with isolated anteromedial or posterolateral bundle-deficient anterior cruciate ligament

Kondo E, Merican AM, Yasuda K, Amis AA

Arthroscopy, 2014 Mar;30(3):335-43.
PMID: 24581258 DOI: 10.1016/j.arthro.2013.12.003

The purpose of this study was to clarify the changes in the kinematics of the knee that result from isolated deficiency of the anteromedial (AM) or posterolateral (PL) bundle.

Matched MeSH terms: Joint Instability/physiopathology*
Knee laxity of Malaysian adults: gender differentials, and association with age and anthropometric measures

Zyroul R, Hossain MG, Azura M, Abbas AA, Kamarul T

Knee, 2014 Mar;21(2):557-62.
PMID: 23473894 DOI: 10.1016/j.knee.2012.12.013

BACKGROUND: Knee laxity measurements have been shown to be associated with some medical conditions such as chronic joint pain and collagen tissue diseases. The aim of this study was to determine the effects of demographic factors and anthropometric measures on knee laxity.
MATERIALS AND METHODS: Data were collected from 521 visitors, staffs and students from the University Malaya Medical Centre and University of Malaya between December 2009 and May 2010. Knee laxity was measured using a KT-1000 arthrometer. Multiple regression analysis was used to find the association of knee laxity with age and anthropometric measures.
RESULTS: Using ANOVA, knee laxity did not show significant differences among ethnic groups for both genders. The average knee laxity in men was 3.47 mm (right) and 3.49 mm (left); while in women were 3.90 mm (right) and 3.67 mm (left). Knee laxity in women was significantly higher (right knee p<0.01 and left knee p<0.05) than men. Right knee laxity of men was negatively associated with height (p<0.05) and BMI (p<0.05); also a negative association was observed between left knee laxity and BMI (p<0.05). Overweight and obese men had less knee laxity than normal weight and underweight individuals. Elderly men and women (age 55 and above) had lower knee laxity (p<0.01) than young adults (ages 21-39).
CONCLUSION: These results suggest that age and body size are important factors in predicting knee laxity.
KEYWORDS: Age; Anthropometric measures; Joint mobility; KT 1000; Knee laxity

Matched MeSH terms: Joint Instability/physiopathology*
Effect of the Timing of Anterior Cruciate Ligament Reconstruction on Clinical and Stability Outcomes: A Systematic Review and Meta-analysis

Lee YS, Lee OS, Lee SH, Hui TS

Arthroscopy, 2018 02;34(2):592-602.
PMID: 28974333 DOI: 10.1016/j.arthro.2017.07.023

PURPOSE: The purpose of this systematic review and meta-analysis was to evaluate the effect of the timing of anterior cruciate ligament (ACL) reconstruction on clinical and stability outcomes by analyzing high-quality studies that assessed timing as a primary objective.
METHODS: The MEDLINE, EMBASE, and Cochrane database were systematically searched. The inclusion criteria were as follows: (1) English articles, (2) noncomparative study or relevant study reporting clinical and/or stability results, and (3) timing of the ACL reconstruction as a primary objective. Study type, level of evidence, randomization method, exclusion criteria, number of cases, age, sex, timing of ACL reconstruction, follow-up, clinical outcomes, stability outcomes, and other relevant findings were recorded. Statistical analysis of the Lysholm scores and KT-1000 arthrometer measurements after early and delayed ACL reconstruction was performed using R version 3.3.1.
RESULTS: Seven articles were included in the final analysis. There were 6 randomized controlled trials and 1 Level II study. Pooled analysis was performed using only Level I studies. All studies assessed the timing of ACL reconstruction as a primary objective. The definition of early ranged broadly from 9 days to 5 months and delayed ranged from 10 weeks to >24 months, and there was an overlap of the time intervals between some studies. The standard timing of the delayed reconstruction was around 10 weeks from injury in the pooled analysis. After pooling of data, clinical result was not statistically different between groups (I2: 47%, moderate level of heterogeneity). No statistically significant difference was observed in the KT-1000 arthrometer measurements between groups (I2: 76.2%, high level of heterogeneity) either.
CONCLUSION: This systematic review and meta-analysis performed using currently available high-quality literature provides relatively strong evidence that early ACL reconstruction results in good clinical and stability outcomes. Early ACL reconstruction results in comparable clinical and stability outcomes compared with delayed ACL reconstruction.
LEVEL OF EVIDENCE: Level II, a systematic review and meta-analysis of Level I and II studies.

Matched MeSH terms: Joint Instability/physiopathology
Fulltext Primary stability recognition of the newly designed cementless femoral stem using digital signal processing

Baharuddin MY, Salleh ShH, Hamedi M, Zulkifly AH, Lee MH, Mohd Noor A, et al.

Biomed Res Int, 2014;2014:478248.
PMID: 24800230 DOI: 10.1155/2014/478248

Stress shielding and micromotion are two major issues which determine the success of newly designed cementless femoral stems. The correlation of experimental validation with finite element analysis (FEA) is commonly used to evaluate the stress distribution and fixation stability of the stem within the femoral canal. This paper focused on the applications of feature extraction and pattern recognition using support vector machine (SVM) to determine the primary stability of the implant. We measured strain with triaxial rosette at the metaphyseal region and micromotion with linear variable direct transducer proximally and distally using composite femora. The root mean squares technique is used to feed the classifier which provides maximum likelihood estimation of amplitude, and radial basis function is used as the kernel parameter which mapped the datasets into separable hyperplanes. The results showed 100% pattern recognition accuracy using SVM for both strain and micromotion. This indicates that DSP could be applied in determining the femoral stem primary stability with high pattern recognition accuracy in biomechanical testing.

Matched MeSH terms: Joint Instability/physiopathology*
A study of joint mobility in a normal population

Seow CC, Chow PK, Khong KS

Ann Acad Med Singap, 1999 Mar;28(2):231-6.
PMID: 10497673

Joint hypermobility is a clinical entity that has been little studied in Southeast Asia in contrast to the many studies that have been conducted in the West. A pioneer study was conducted in Singapore involving 306 subjects from the three major races i.e. Chinese, Malays and Indians. Their ages ranged from 15 to 39 years. The objective was to ascertain the joint mobility profile in a study sample representative of the Singapore population and the prevalence of joint hypermobility amongst normal individuals. Joint mobility was assessed using criteria according to Carter and Wilkinson modified by Beighton et al. The distribution of the three major races in the study sample was based on the 1990 census of the Singapore population. The prevalence of joint hypermobility was found to be 17%. The results showed that joint mobility decreases with age and that females had consistently higher degree of joint mobility compared to males throughout the age group. Among the racial groups, Malays had the highest degree of joint mobility followed by Indians and Chinese.

Matched MeSH terms: Joint Instability/physiopathology
The effectiveness of a pre-operative home-based physiotherapy programme for chronic anterior cruciate ligament deficiency

Keays SL, Bullock-Saxton JE, Newcombe P, Bullock MI

Physiother Res Int, 2006 Dec;11(4):204-18.
PMID: 17236528

BACKGROUND AND PURPOSE: Little evidence supports the prescription of pre-operative rehabilitation in the treatment of chronic anterior cruciate ligament-deficient (ACLD) subjects. The aim of the present study was to assess the effectiveness of a specific six-week pre-operative exercise programme on ACLD knees.
METHOD: A single, masked, controlled study was designed. This comprised two matched groups of 12 chronically ACLD patients awaiting reconstruction and a group of 12 matched uninjured control subjects. Only one ACLD group received a home-based exercise and educational programme. Assessment before and after the exercise intervention included: knee joint stability (clinical and KT1000 evaluation); muscle strength (Cybex II); standing balance and functional performance (agility, [corrected] and subjective tests).
RESULTS: At the time of initial assessment there were no statistically significant differences in any measures for the two ACLD groups but both ACLD groups were significantly different from the uninjured control group as regards quadriceps strength and function. Measures taken after six weeks showed no significant improvement in the untreated ACLD group or in the uninjured control group. The treated ACLD group showed significant improvement in the following measures: quadriceps strength measured at 60 degrees and 120 degrees per second (p < 0.001); single leg standing balance with eyes closed (p < 0.001); instrumented passive stability at 20 lb (89 N) force (p = 0.003); agility and subjective performance (p < 0.001). The incidence of unstable episodes had decreased in the treated ACLD group, reducing further damage to the joint.
CONCLUSION: This study leaves little doubt that pre-operative physiotherapy had a positive effect on motor function in ACLD subjects and should be prescribed routinely to maximize muscle stabilizing potential prior to reconstruction. Patients report improved stability and, in certain cases, may avoid surgery. The finding that exercise increased the passive stability of the joint was unexpected and requires further investigation.

Matched MeSH terms: Joint Instability/physiopathology