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Results for “Bone Malalignment”

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At least 145 records · Page 8Linked to original sources

PubMed2001

Polyethylene wear and variations in knee kinematics.

A six-station knee wear simulator was used to test a posterior cruciate-retaining total knee arthroplasty design. Six implants each were tested in three groups; low intensity, high intensity, and malalignment using kinematic inputs from normal gait data, more severe loading conditions, and 3 degrees varus malalignment, respectively. For each group, gravimetric wear of the polyethylene inserts was measured for 5,000,000 cycles. Knee wear testing showed significantly different results for the three groups. Low intensity group inserts had mean wear rates of 3.1 (+/- 1.2) mg per million cycles. High intensity group inserts had significantly higher mean wear rates of 7.4 (+/- 2.7) mg per million cycles. Malalignment group inserts had the highest wear rates of 9.2 (+/- 3.3) mg per million cycles. The wear generated in the knee simulator seems to be dependent on the relative motions and loads at the articulating surface. The high intensity groups were subjected to motions that included reciprocating anteroposterior translations and a higher peak axial load than the low intensity group. This resulted in increasing the amount of wear. Varus malalignment also increased the total wear significantly. These results may explain some of the wide variations in wear seen in retrieved knee implants.

Biomechanical Phenomena↗

PubMed2004

The effect of body weight on progression of knee osteoarthritis is dependent on alignment.

OBJECTIVE: Whereas obesity increases overall loading of the knee, limb malalignment concentrates that loading on a focal area, to the level at which cartilage damage may occur. This study evaluated whether the effect of body weight on progression of knee osteoarthritis (OA) differs depending on the degree of limb malalignment. METHODS: The study population comprised 228 veterans and community recruits with symptomatic knee OA (pain on most days and radiographic disease) who volunteered to participate in a natural history study and from whom baseline radiographs were obtained to assess alignment; 227 (99.6%) completed a 30-month followup. Of 403 knees assessed at baseline, 394 (97.8%) were followed up. Participants' body mass index (BMI) was assessed at each examination. The main outcome measure was progression of knee OA, defined as narrowing of the tibiofemoral joint space by 1 grade (semiquantitative scale 0-3) on radiographs of the fluoroscopically positioned knee. The association between BMI and the risk of knee OA progression was assessed after adjusting for age, sex, and limb alignment, using logistic regression and generalized estimating equations. RESULTS: Of 394 knees, 90 (22.8%) showed disease progression, and limb alignment was strongly associated with progression risk. The risk of progression increased with increasing weight (for each 2-unit increase in BMI, odds ratio [OR] for progression 1.08, 95% confidence interval [95% CI] 1.00-1.16). However, among those knees with neutral alignment (0-2 degrees ), increases in BMI had no effect on risk of progression (OR 1.00), and in those with severe malalignment (> or =7 degrees ), the effect was similarly null (OR 0.93). The effect of BMI on progression was limited to knees in which there was moderate malalignment (OR per 2-unit increase in BMI 1.23, 95% CI 1.05-1.45). CONCLUSION: Although elevated BMI increases the risk of knee OA progression, the effect of BMI is limited to knees in which moderate malalignment exists, presumably because of the combined focus of load from malalignment and the excess load from increased weight. This has implications for clinical recommendations and for trials testing weight loss in those with knee OA.

Aged↗

PubMedDate not supplied

Structural joint changes, malalignment, and laxity in osteoarthritis of the knee.

OBJECTIVE: To assess the relationship between (i) structural joint changes (i.e. joint space narrowing and osteophyte formation) and laxity and (ii) joint malalignment and laxity in osteoarthritis (OA) of the knee. METHODS: A cross-sectional study was carried out on 35 outpatients with osteoarthritis of the knee. Weight-bearing radiographs of the knees were used to assess joint space narrowing (JSN) and osteophyte formation. Knee joint laxity was assessed using a device that measures the angular deviation of the knee in the frontal plane (varus-valgus laxity). Malalignment was assessed using a goniometer. All analyses were performed using knees as units of analysis (i.e. 70 knees). RESULTS: The mean laxity of 70 knees was 8.0+/-4.1 degrees. Knees with minute JSN were significantly more lax than knees with no JSN. There was no significant relationship between osteophyte formation and laxity. Malaligned knees were significantly more lax than aligned knees. CONCLUSION: Both joint space narrowing and malalignment are related to laxity. These results support the premise that biomechanical factors play a role in the degeneration of the osteoarthritic knee joint.

Adult↗

PubMed1999

Calcaneocuboid malalignment in clubfoot.

In a series of 179 clubfeet treated surgically with a follow-up of 3 to 14 years, the clinical significance of calcaneocuboid malalignment was assessed on the basis of a standardized anteroposterior radiograph. The revision rate was 15% and the clinical requirement for a further soft tissue release was related to the talocalcaneal and calcaneocuboid angles. Calcaneocuboid malalignment does not have an adverse effect on the good prognosis of an otherwise well-corrected foot and does not alter the surgery needed to improve a clearly uncorrected foot. When talocalcaneal correction is doubtful, calcaneocuboid malalignment should tilt the balance toward a revision and is of value when the navicular has yet to ossify. Surgical release of the calcaneocuboid joint is unnecessary, particularly the lateral dissection, provided that the medial and subtalar dissection is complete.

Adolescent↗

PubMed2000

The sulcus angle and malalignment of the extensor mechanism of the knee.

Anterior knee pain due to dysplasia of the extensor mechanism is common. We have studied 137 knees (103 patients) in order to identify a rapid and reproducible radiological feature which would indicate the need for further analysis. Overall, 67 knees (49%) had at least one radiological abnormality; 70 (51%) were considered normal. There were five cases of Dejour type-3 dysplasia of the femoral trochlea, nine of type-2 and 12 of type-1. There were 49 cases of patella alta and five of patella infera. Four knees had an abnormal lateral patellofemoral angle (patellar tilt), and in 15 knees there was more than one abnormality. Classification of trochlear dysplasia was difficult and showed poor reproducibility. This was also true for the measurement of the lateral patellofemoral angle. Patellar height was more easily measured but took time. The sulcus angle is an easily and rapidly measurable feature which was reproducible and was closely related to other features of dysplasia of the extensor mechanism. The finding of a normal sulcus angle suggested that seeking other radiological evidence of malalignment of the extensor mechanism was unlikely to reveal additional useful information. The severity of other features of dysplasia of the extensor mechanism correlated with increasing sulcus angle.

Adolescent↗

PubMed2002

Malalignment: signs and significance.

Malalignment of the vertebrae, in patients suspected of blunt spinal trauma, is the quintessential sign of spinal injury. Malalignment is obvious in displaced fractures and dislocations but is rarely considered in the diagnosis because of the obvious injury. In patients with more subtle injuries such as those limited to ligamentous structures, vertebral malalignment is the only radiographic sign that leads one to the recognition of the injury. Equally important is the fact that vertebral malalignment may be congenital and may be due to physiologic movement as well as radiographic patient positioning. Recognition of the pattern of traumatic malalignment as distinguished from the appearance of non-traumatic malalignment is essential to accurate radiologic diagnosis. Because malalignment is critical to the radiographic assessment of blunt cervical spine injury, this presentation is limited to the cervical spine. The format of the article includes signs of physiologic and traumatic malaignment as seen on antero-posterior and lateral radiographs of the cervico-cranium and the lower cervical spine.

Bone Malalignment↗

PubMed2005

Osteotomy about the knee: applications, techniques, and results.

Varus or valgus malalignment of the knee may be either a cause or a consequence of unicompartmental knee arthritis in young, active adults. Proximal tibial osteotomy for the varus knee and distal femoral osteotomy for the valgus knee have been used for decades to manage this condition; however, their use has decreased significantly in recent years as the popularity of unicompartmental and total knee arthroplasty has grown. With the advent of biologic resurfacing techniques for focal full-thickness articular cartilage injury, combined or staged high tibial osteotomy is becoming increasingly popular. In addition, in the face of cruciate ligamentous instability with or without posterolateral corner instability coupled with varus malalignment, high tibial osteotomy with and without ligament reconstruction provides a solution to complex orthopedic problems. Recent long-term follow-up studies have concluded osteotomy allows for improved function and pain relief in properly selected young patients.

Arthroplasty, Replacement, Knee↗

PubMed2004

Computed tomography determined femoral torsion is not accurate.

INTRODUCTION: Computed tomography (CT) is considered the method of choice for detecting rotational malalignment of the femur. However, it is unclear how reliable the method is, and what the causes are of potential inaccuracies. MATERIALS AND METHODS: To address these issues three observers measured the CT images of the femur of 76 patients on two separate occasions. The images were made during follow-up of a unilateral femoral shaft fractures. Rotational malalignment was determined by comparing the torsion angle of the injured to the noninjured leg. RESULTS: The pooled intraobserver variance was 3.9 degrees and interobserver variance 4.1 degrees. Of the two measurements of one observer 95% were up to 10.8 degrees different, and between observers 95% of the measurements were up to 15.6 degrees different. CONCLUSIONS: CT measurements of rotational malalignment of the femur are not accurate. This is due principally to the difficulty in defining a line through the axis of the femoral neck. The accuracy can be improved by taking the average of two measurements.

Bone Malalignment↗

PubMed1994

Effect of limb malrotation on malalignment and osteoarthritis.

This article's goal is to review the causes of limb rotation and arthritis and establish the correlation between the two entities. Evidence cited in this article demonstrates that malrotation is coupled with axial malalignment and both are associated with arthrosis of the hip, knee, and ankle. The clinical significance of this observation is that the prognosis of arthrosis developing in a malrotated limb may be predicted. Furthermore, the durability of an osteotomy, arthroplasty, or other surgical intervention may be limited if the intrinsic rotational deformity is not addressed.

Bone Malalignment↗

PubMed1998

Intraoperative control of axes, rotation and length in femoral and tibial fractures. Technical note.

In an effort to limit the amount of soft tissue dissection at the fracture site, indirect reduction and minimally invasive fixation techniques have been developed to treat femoral and tibial fractures. These techniques, which do not rely upon anatomical reduction of the fracture fragments, are technically difficult. Correct limb length, axial alignment in the frontal and sagittal plane, and rotation must be assessed using means other than open reduction. In this technical note, some simple and effective intraoperative clinical examination and radiographic techniques to determine limb alignment are described. These include: the 'cable techniques' for the determination of varus-valgus malalignment; the 'hypertension test', 'radiographic recurvatum sign', 'tibial plateau sign', and 'meterstick technique' for length analysis; and the 'hip rotation test', 'lesser trochanter shape sign', 'cortical step sign', and 'diameter difference sign' for rotational analysis. For each of the listed techniques, basic principles, technical instructions, limitations, advantages, and disadvantages are described.

Bone Malalignment↗

PubMed1994

New procedures for tightening knee collateral ligaments in conjunction with knee realignment osteotomy.

Collateral ligament laxity has recently been recognized as an important component of frontal plane malalignment. The authors have developed new surgical techniques to re-tension lax collateral ligaments. Twenty-three collateral ligament re-tensioning with bony alignment were carried out in 17 patients, with 19 knees being graded excellent, 2 fair, and 2 poor. Recurrence of significant laxity was noted in one patient.

Adolescent↗

PubMed2005

Reconstruction of the medial patellofemoral ligament for painful patellar subluxation in distal torsional malalignment: a case report.

Complex two-level rotational malalignment of the lower extremity can cause maltracking of the patella with anterior knee pain. Double derotation osteotomy would correct the underlying pathology. However, it carries a high risk of complications such as nerve and vessel damage. We report a case of rotational malalignment in the femur and the tibia associated with trochlear dysplasia, which causes painful patellar instability. The patient was successfully treated with reconstruction of the medial patellofemoral ligament and lateral release. Although the malrotation was not addressed, the position of the patella was corrected, and no dislocation occurred during a follow-up of 10 months.

Adolescent↗

PubMed1994

Biomechanics of malalignment.

This article summarizes the range and variation of femorotibial alignment, the horizontal orientation of the hip, knee, and ankle joint line, and other pertinent anatomic factors of the lower extremity in normal population groups evenly divided according to gender and age. Although the present data deals only with a two-dimensional frontal plane analysis, it should provide valuable information for subsequent clinical and basic science investigations.

Adult↗

PubMed2004

Revision of malaligned triple arthrodesis: a case report.

Malalignment of a triple arthrodesis can pose significant challenges to the foot and ankle surgeon. Lack of a plantigrade foot will not be well tolerated by the patient and will often require revision of the original surgery. This article presents a review of the treatment algorithm used to address this unique problem. A case study based on this approach is also presented.

Arthrodesis↗

PubMed2005

Mini-incision total knee arthroplasty can increase risk of component malalignment.

UNLABELLED: Interest in minimal-incision total knee arthroplasty has increased in recent years. We compared a group of 30 patients who had total knee arthroplasty with a mini-incision to a similar group of 30 patients who had total knee arthroplasty with a standard length incision. The minimal-incision group had some minor early advantages (less pain medication use, earlier improvement in range of motion), but these advantages dissipated by 3 months followup. Radiographic evaluations showed that four of the 30 patients with minimal incisions had tibial component varus malalignment (< 87 degrees ), whereas no patients with the standard length incision had malalignment. Although total knee arthroplasty performed using a minimal incision may provide some early advantages, minimal incisions can impede a surgeon's vision and may influence component alignment and possibly compromise long-term outcome. LEVEL OF EVIDENCE: Therapeutic study, Level III-1 (retrospective comparative study). See the Guidelines for Authors for a complete description of levels of evidence.

Aged↗

PubMed1997

Patellofemoral malalignment.

Anterior knee pain represents one of the most common musculoskeletal complaints of adolescents. It is a disorder in which there is broad clinical experience and yet it represents a difficult and frustrating entity for the athlete to endure and for the physician to treat. An appropriate clinical examination and selected diagnostic studies can define the diagnosis and the introduction of conservative therapy usually will correct the problem. Occasionally, surgical intervention is required, and debate remains as to the optimal techniques that should be used.

Adolescent↗

PubMed2006

Influence of lower-limb torsion on long-term outcomes of tibial valgus osteotomy for medial compartment knee osteoarthritis.

BACKGROUND: The results of tibial osteotomy used to treat osteoarthritis of the medial compartment of the knee deteriorate over time even when the initial correction is optimal. Studies have shown that tibial and femoral torsion and the femorotibial index (tibial torsion minus femoral torsion) contribute, together with coronal malalignment, to the development of single-compartment knee osteoarthritis. The objective of our study was to evaluate the impact of femoral and tibial torsion and of coronal realignment on the long-term clinical and radiographic outcomes of valgus tibial osteotomy. METHODS: A function score was calculated for sixty-eight patients at a mean of thirteen years after the osteotomy. Anteroposterior single-leg-stance radiographs were used to evaluate loss of the femorotibial joint space. Goniometry was used to measure coronal malalignment preoperatively, at one year, and at the time of the last follow-up, and postoperative computed tomography was performed to measure femoral anteversion and tibial torsion and to calculate the femorotibial index. We looked for associations linking body mass index, initial loss of joint space, coronal malalignment, femoral and tibial torsion, the femorotibial index, and functional outcomes. RESULTS: Worse outcomes were associated with changes in coronal alignment (>/=2 degrees ) over time, which were associated with deterioration of the femorotibial space. Femoral anteversion was significantly greater in patients in whom valgus increased over time than in those in whom valgus decreased over time. Stability of coronal alignment seemed to be dependent on a linear relationship between the femorotibial index and the degree of postoperative realignment. A body mass index of >25 kg/m(2) was associated with a long-term loss of coronal realignment. Preoperative loss of the medial femorotibial joint space, coronal alignment at one year, and age were not associated with secondary malalignment or functional outcomes. CONCLUSIONS: Long-term success of a valgus tibial osteotomy is related to the stability over time of the postoperative coronal realignment. Therefore, the results of our study suggest that modifying the realignment according to the extent of femoral anteversion may improve long-term outcomes.

Arthrometry, Articular↗

PubMedDate not supplied

[Radiological determination of femoral rotation deformity--computerized tomography, optimized measurement accuracy and exposure dosage].

58 Patients, suspicious to have rotation deformity of the femur, were examined. To compare the value of diagnostic methods in measuring the degree of malrotation we estimated this degree using clinical examination and calculated the anteversion of the femoral neck, taking radiographs in the technique of Dunn and Rippstein, and a modified method of computed tomography. Only in twelve cases the direction of malrotation was corresponding in all three methods, although considerable variations in quantitative results were noted. Maintaining the exact position of the patient, necessary to get reproducible results using conventional X-ray technique, was impossible in most cases of patients with posttraumatic joint-stiffness and malalignment. Determination of femoral neck anteversion using this modified method of CT is a quick, reproducible technique to calculate the degree of malrotation, insensitive to the position of the patient. By means of this CT method it was possible to approach the highest accuracy in precise preoperative planing. Furthermore the radiation exposure could be reduced in a range of 20%-40%.

Adult↗