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At least 19 recordsLinked to original sources
PubMed2004

[Corrective osteotomy in primary varus, double varus and triple varus knee instability with cruciate ligament replacement].

Osteochondral lesions and osteoarthritis in young patients are often caused by chronic knee instability in varus malaligned knees. We present the indication, operative technique, and results of 57 patients treated by simultaneous high tibial osteotomy and cruciate ligament reconstruction. The indication for simultaneous high tibial valgus osteotomy and ACL reconstruction is chronic anterior knee instability in varus knees of patients under 40 years of age. In these patients, medial meniscus deficiency secondary to prior injuries and/or chronic knee instability have frequently led to unicompartmental (medial) tibiofemoral degenerative changes. The average correction angle of the osteotomy was 7 degrees (4-10). Subjectively, all patients reported an improvement of preoperative swelling, pain, and instability. Additional cartilage surgery or meniscus implantation did not significantly alter the clinical score values. Complications occurred in four patients. Unstable varus malangulated knees can be sufficiently treated by osteotomy and cruciate ligament plasty and is suggested as cost-effective therapy with good short-term results. Performing both operations in one procedure facilitates early rehabilitation and return of the patients back to the activities of daily living and sports.

Adult↗
PubMed2005

Measurement of varus angulation after femoral varus osteotomy in Legg-Calvé-Perthes disease.

Femoral varus osteotomy is an established therapy for Legg-Calvé-Perthes disease. The amount of surgical varus angulation is usually measured as the difference between the preoperative and the postoperative projected femur neck-shaft angle. We developed a more accurate measurement technique that considers changes of leg position and assessed the surgical varus angulation on two postoperative radiographs of each of 65 uniplanar femoral varus osteotomies. The mean difference between both surgical varus angulation measurements was 2.0 degrees +/- 1.4 degrees (range 0.0-5.0 degrees), the Pearson's correlation result was r = 0.96. The mean surgical varus angulation was 18.7 degrees +/- 7.3 degrees (range -2.5 to 43.5 degrees). Comparison with the preoperatively planned angulation showed a mean difference of 6.6 +/- 5.2 degrees (range 0.25-22.5 degrees).

Child↗
PubMedDate not supplied

Relative tibial and femoral varus as a predictor of progression of varus deformities of the lower limbs in young children.

Many young children present to pediatric orthopaedic surgeons with genu varum and mild beaking of the medial metaphysis on x-ray. Predicting whether these deformities will progress is challenging. In addition, there is no consensus as to whether these children should all be classified as having Blount disease. To avoid this latter problem, the authors included in this study all children presenting with bowed legs, regardless of diagnosis. With the aim of improving the ability to predict progression, the authors tested the hypothesis that patients with progression have more tibial than femoral varus. The authors reviewed 173 varus limbs of 98 patients younger than 4 years old. The authors determined the angular deformity in both femur and tibia by measuring the angles between their mechanical axes and the transverse axis of the knee, and determined the contribution of tibial deformity as a percentage of the total (%DT). The metaphyseal-diaphyseal angles of the tibia (MDA) were also measured to compare the value of that test with the %DT. There were 22 limbs with progressive and 141 limbs with resolving varus. Both the MDA and %DT were significantly different between groups. Tibial varus was found to exceed femoral varus in all patients with progression and also in several patients whose deformity resolved spontaneously. Although more specific and more sensitive than the MDA, the %DT is a good, but not perfect, predictor of progression. However, all patients in this series with both a %DT >50% and an MDA of 16 degrees or greater went on to progress. Using both of these tests together may therefore provide the surgeon with a reliable indicator of the children who would benefit from surgical correction.

Bone Malalignment↗
PubMed2005

Total knee arthroplasty for profound varus deformity: technique and radiological results in 173 knees with varus of more than 20 degrees.

One hundred seventy-three knees in 117 patients with varus deformity exceeding 20 degrees were prospectively evaluated. Using selective posteromedial release, reduction osteotomy of posteromedial tibial flare, and extra-articular tibial osteotomy, with the preservation of medial collateral ligament integrity, mean tibiofemoral angle of 22.7 degrees varus preoperatively (range, 15 degrees-62 degrees) was corrected to 5.3 degrees valgus (range, 2 degrees-9 degrees) postoperatively. Eighty-six percent of the knees were in 4 degrees to 10 degrees valgus postoperatively. Mean Knee Society score improved from 22.8 (range, 0-64) to 91.1 (range, 52-99), and function score from 22.8 (range, 0-64) to 72.1 (range, 5-100) at 2.6 years (range, 2-9 years). Mean femoral component valgus was 95.5 degrees (range, 92 degrees-98 degrees), and mean tibial component valgus was 89.8 degrees (range, 86 degrees-94 degrees). Of 30 grafts for posteromedial tibial defects, 28 were successfully incorporated. No patient reported significant instability. Three knees (1.7%) showed tibial component loosening with recurrence of deformity. Correction of severe varus deformity by the technique reported can successfully restore alignment, pain-free motion, and stability.

Aged↗
PubMed2004

Distal femoral cut perpendicular to the mechanical axis may induce varus instability in flexion in medial osteoarthritic knees with varus deformity in total knee arthroplasty: a pitfall of the navigation system.

Two factors that influence the external rotation angle of the femoral rotational axis in total knee arthroplasty (TKA) were assessed in 40 medial osteoarthritic knees with varus deformity. First, the anatomic configuration of the femur was assessed using standardized radiographs of the patients' lower extremities before TKA. Second, the degree of medial soft tissue release was assessed during TKA. The radiographs showed that the characteristics of the femur were lateral bowing of the shaft and external rotation of the condyle in the coronal plane. Therefore, when the distal femur is cut perpendicular to the mechanical axis, the cut surface may be in too much of a valgus position. Furthermore, some degree of medial soft tissue release was necessary in all knees. Medial soft tissue release rotates the femur externally in extension in the coronal plane, and it rotates the femur externally around the femoral axis in flexion relative to the tibia. A distal femoral cut in too much of a valgus position and medial soft tissue release induces varus instability in flexion in knees with lateral bowing of the femoral shaft. Anatomic variation such as femoral bowing should be considered when a navigation system is used for TKA because the navigation system shows only the mechanical axis.

Aged↗
PubMed1991

Primary total knee arthroplasty in patients with severe varus deformity. A comparative study.

Varus deformity is a common finding in candidates for total knee arthroplasty (TKA), but very little has been written concerning the problems encountered in correcting these deformities at the time of arthroplasty. Compared to patients without deformities, this group of patients require more attention to the technical aspects of the arthroplasty, especially bony alignment and ligament balancing. Specific operative techniques used to correct severe varus deformities at primary TKA were evaluated, and the clinical and roentgenographic results were compared with those of a control group of patients without preoperative angular deformity. Operative findings and clinical results in 27 knees (20 patients) with a minimum preoperative varus deformity of 20 degrees (average follow-up period, 58.7 months; range, 24-102 months) were compared with those of 40 knees (31 patients) with a preoperative angulatory deformity of less than 5 degrees varus or valgus (average follow-up period, 50.0 months; range, 24-90 months), in whom a minimally constrained, posterior-cruciate-ligament-sparing prosthesis was implanted. Operative time was an average of 30 minutes longer in the varus deformity group. The average knee evaluation score in the varus group was 89 points, and for the nondeformity group it was 92 points (p less than 0.02). There were no fair or poor results in the varus deformity group; there was one poor result in the nondeformity group. Postoperative knee are of motion was 98 degrees in the varus deformity group and 107 degrees in the nondeformity group. After arthroplasty, the average angle between the mechanical axis of the femur and the tibia was 3 degrees varus in the varus deformity group and 0 degree varus in the nondeformity group (p less than 0.006). Postoperative functional scores of patients in the varus deformity group approached, but were not equal to, the nondeformity group. Greater variability in results and longer operative times were needed in the varus deformity group. Postoperative alignment of the varus deformity group tended to be in residual varus.

Adult↗
PubMed2006

[Techniques of soft tissue balance in total knee arthroplasty of varus knee].

OBJECTIVE: To analyze formation of the varus angle of the knee due to osteoarthritis and to explore techniques of the soft tissue balance in the total knee arthroplasty(TKA). METHODS: One hundred patients with 145 varus knees (18 males, 25 varus knees; 82 females, 120 varus knees) underwent TKA from January 1999 to December 2003. Their ages averaged 62.4 years (range, 45-80 years), and their HSS(hospital of special surgery)scores were 38.0 +/- 3.2 points. Before operation,all the patients were measured in the alignment of the lower extremity, accurate bone-cutting was performed, and their static alignment was achieved. Then, the soft tissue release was made. The release performance consisted of 3 steps: release before the bone-cutting, release during the bone-cutting, and release after the bone-cutting. Release of the medial ligament and capsule, elimination of the osteophytes, and release of the lateral patellar retinaculum were more important. RESULTS: The varus angles in these patients were 9.2 +/- 3.1 degrees before operation. Among them, the varus angles caused by the soft tissue imbalance accounted for 53.2%, and caused by the bone structure accounted for 46.8%; and the latter caused by the tibia varus, 22.8%, and by the tibia plateau destruction, 24.0%. There was no significant difference between the varus angles caused by the soft tissue imbalance and the varus angles caused by the bone structure deformity (P > 0.05). According to the postoperative imaging studies, the correction degree for the varus angles by the bone-cutting was 4.3 degrees, which represented 27.9% of the total corrected angles, and the correction degree for the varus angles corrected by the soft tissue balance was 10.7 degrees, which represented 72.1% of the total corrected angles. The HSS scores were 87.0 +/- 4.5 points after operation, and the difference between preoperation and postoperation was significant. CONCLUSION: The varus knee due to osteoarthritis results from the varus angle in the bone structure and the angles caused by the imbalance of the collateral ligaments and the soft tissues around the knee. The latter causative factor is more important in the formation of the varus knee and should only be corrected through the soft tissue release. The more important part to be released is the attachments of the medial ligament and the posterior capsule. The release performance should be followed by the principles, i.e., step by step, tests at all the time, and avoidance of the excessive release.

Aged↗
PubMed2001

Muscle strength in knee varus and valgus.

PURPOSE: The purpose of this study was to investigate the lower-limb muscle strength in knee varus-valgus and its dependence on knee varus-valgus position. The hypothesis was that humans could differentially contract the medial and lateral muscles crossing the knee and generate significant moments in knee valgus-varus. METHODS: The subjects sat with the knee at full extension and secured from the medial, lateral, anterior, and posterior sides. Both hips were clamped from the lateral sides. The subjects adducted (abducted) the ipsilateral hip during the knee valgus (varus) maximal voluntary contraction with EMG signals recorded from muscles crossing the knee and knee joint moments measured using a six-axis force sensor. Frontal plane tibiofemoral movement was evaluated using a fluoroscope. RESULTS AND CONCLUSIONS: The subjects differentially contracted the medial and lateral muscles, and fluoroscope images showed the corresponding tibiofemoral movement. The subjects showed considerable strength in knee varus and valgus. The active knee varus strength increased significantly with increasing knee valgus angle, and the valgus strength was significantly higher when the knee was in varus position (P < 0.039). Active valgus muscle strength at 5 degrees knee varus was significantly higher than the active varus strength at 5 degrees valgus (P = 0.002). The passive resistance moment increased linearly with increasing knee valgus and varus angles, and it accounted for 28% and 35% of the total (active plus passive) moment at the 5 degrees varus and 5 degrees valgus, respectively. The significant varus-valgus muscle strength demonstrated in this study may play important roles in performing various functional tasks, maintaining joint stability, and preventing potential injuries, whether the major load and motion at the knee is in the frontal plane or not.

Adult↗
PubMed2001

Strategies of muscular support of varus and valgus isometric loads at the human knee.

In this paper we studied how subjects activate their muscles in response to static varus and valgus loads at the knee. The muscles' contributions to the external moments were estimated using an EMG driven biomechanical model of the knee. The individual muscle activation and loading patterns were examined to identify the strategies that the nervous system uses to support varus and valgus knee moments. It was found that the (1) co-contraction of the hamstrings and quadriceps, and (2) activation of the gracilis and tensor fascia lata increased with the increasing magnitude of the varus and valgus moments. These 2 activation patterns provided positive support of valgus and varus loads at the knee The sartorius appears to be activated to provide positive support of valgus loads at the knee, whereas during varus moments this muscle increases the varus load on the knee, i.e. provides negative support. Generally, the hamstrings and quadriceps co-contraction contributed to most of the muscular support of the varus and valgus moments. In addition, co-contraction supported 11-14% of the external moment in pure varus and pure valgus respectively. It appears that there are activation strategies with the specific purpose to support varus and valgus moments, albeit small, which suggest dual goals of the neuromotor system during the support of varus and valgus moments.

Adult↗
PubMed1998

Muscular resistance to varus and valgus loads at the elbow.

Although the contributions of passive structures to stability of the elbow have been well documented, the role of active muscular resistance of varus and valgus loads at the elbow remains unclear. We hypothesized that muscles: (1) can produce substantial varus and valgus moments about the elbow, and (2) are activated in response to sustained varus and valgus loading of the elbow. To test the first hypothesis, we developed a detailed musculoskeletal model to estimate the varus and valgus moment-generating capacity of the muscles about the elbow. To test the second hypothesis, we measured EMGs from 11 muscles in four subjects during a series of isometric tasks that included flexion, extension, varus, and valgus moments about the elbow. The EMG recordings were used as inputs to the elbow model to estimate the contributions of individual muscles to flexion-extension and varus-valgus moments. Analysis of the model revealed that nearly all of the muscles that cross the elbow are capable of producing varus or valgus moments; the capacity of the muscles to produce varus moment (34 Nm) and valgus moment (35 Nm) is roughly half of the maximum flexion moment (70 Nm). Analysis of the measured EMGs showed that the anconeus was the most significant contributor to valgus moments and the pronator teres was the largest contributor to varus moments. Although our results show that muscles were activated in response to static varus and valgus loads, their activations were modest and were not sufficient to balance the applied load.

Adult↗
PubMed2004

Effect of distal humeral varus deformity on strain in the lateral ulnar collateral ligament and ulnohumeral joint stability.

BACKGROUND: Recent reports have implicated cubitus varus deformity as a risk factor for the development of late posterolateral rotatory instability of the elbow. The purpose of this study was to determine the biomechanical relationship between cubitus varus and strain in the lateral ulnar collateral ligament and subluxation of the ulnohumeral joint as it relates to posterolateral rotatory instability. METHODS: Eleven fresh-frozen cadaveric elbow joints were mounted in an apparatus that allowed active elbow motion. Supracondylar osteotomies were performed to create cubitus varus deformities of 0 degrees to 30 degrees in 5 degrees increments. Each elbow was loaded with a supination moment of 1.2 Nm and a resistive triceps extension force. Strain in the lateral ulnar collateral ligament and widening of the ulnohumeral joint were measured at each position of varus, and the resulting strain and joint-widening values were averaged. RESULTS: Strain in the lateral ulnar collateral ligament was found to increase as the cubitus varus deformity increased. Likewise, the ulnohumeral joint space was seen to progressively widen with increasing cubitus varus. Strain was significantly increased at 30 degrees of varus deformity (p = 0.03), and widening of the ulnohumeral joint space was significantly increased at 25 degrees of varus deformity (p = 0.004). When differences in the size of the cadaveric specimens were accounted for in an analysis of covariance, ligament strain was significantly increased at 25 degrees of varus (p = 0.005) and widening of the ulnohumeral joint space, at 20 degrees (p = 0.01). CONCLUSIONS: Cubitus varus deformity of the elbow increases strain in the lateral ulnar collateral ligament, with a corresponding increase in ulnohumeral joint-opening consistent with the posterolateral rotatory instability of the elbow seen clinically.

Aged↗
PubMed2001

The relationship between postoperative ligament balance and preoperative varus deformity in total knee arthroplasty.

We hypothesize that in knees with severe varus deformities, varus-valgus ligament imbalance tends to remain postoperatively after total knee arthroplasty. The purpose of this study was to evaluate the correlation between preoperative varus deformity and postoperative ligament balance quantitatively measured by stress radiograph using Telos SE in total knee arthroplasty. In this study, 44 knee arthroplasties in 32 patients were evaluated. We defined the angle in varus and valgus stress as "varus angle" and "valgus angle," and the sum of varus angle and valgus angle as "sum of varus-valgus angle." There was a significant correlation between preoperative lateral femoral angle and varus angle (p < 0.0001, r = 0.56), which means that postoperative ligament imbalance tends to remain in knees with preoperative varus deformities. There was a significant correlation between the postoperative period and the sum of varus-valgus angle, which suggests that knees with total knee arthroplasty have potential to increase laxity postoperatively.

Aged↗
PubMed2006

[Changes in knee kinematics and quadriceps and hamstrings moment arms after high valgus and varus tibial "dome" osteotomy: An in vitro study].

PURPOSE OF THE STUDY: Analysis of the correction or over-correction of high valgus and varus tibial osteotomies is generally limited to the frontal plane. Most likely however, the deformation observed radiographically in the frontal plane is simply a one-dimensional expression of a more complex three-dimensional deformation. This might be one of the causes for certain failures after surgery and recurrent problems which are difficult to solve. We proposed using 3D electrogoniometric to measure of the effect of a "dome" osteotomy on patellar and femoro-tibial kinematics and the changes in the moment arms of the knee muscles. MATERIAL AND METHODS: We used five lower limbs harvested from non-fixed cadavers. A "dome" osteotomy was stabilized by external fixation. Three-dimensional analysis of the femoro-tibial and femoro-patellar kinematics was performed using two electrogoniometers with six degrees of freedom. Changes in the lengths of the hamstrings and quadriceps was measured using four LVDT linear variable differential transformers. The muscles lever arms were measured with the tendon excursion method. RESULTS: At 90 degrees flexion, varus osteotomy induced internal rotation while valgus osteotomy induced the opposite effect. Beyond 40 degrees flexion, there was a clear internal rotation of the patella for varus and neutral corrections. Valgus corrections however induced external rotation. The peak lever arm of the quadriceps increased with valgus, while the angle of the peak was higher for varus correction. Valgus appeared to increase the lever arm of the semitendinous. DISCUSSION: Our study demonstrated that the effect of tibial osteotomy is not limited to the frontal plane. Tibial rotations are observed systematically for all corrections in the frontal plane. Varus correction tends to create internal rotation while valgus correction tends to have the opposite effect. Axial correction also affects patellar kinematics. Interanal rotation is induced by varus correction and external rotation by valgus correction. This patellar rotation could result from tibial rotations induced by the different corrections. The loss of the parallelism between the patellar crest and the trochlear groove could produce changes in femoropatellar surface contact and pressure, potentially leading to pain or cartilage degeneration. The maximal value of the quadriceps moment arm appears to increase with valgus. The efficacy of the quadriceps could thus be improved with valgus, potentially increasing extension force. Valgus increases the moment arm, improving limb flexion, while varus correction has the opposite effect. This could explain a loss in flexion amplitude in patients with varus or who underwent varus osteotomy. Tibial osteotomy is designed to correct the deviation solely in the frontal plane but also has effects in all three planes. Further 3D analyses of the morphology and physiology of the knee joint would be needed to better understand the physiological and pathological processes involved.

Biomechanical Phenomena↗
PubMed2006

The contributions of anterior and posterior tibialis dysfunction to varus foot deformity in patients with cerebral palsy.

BACKGROUND: According to traditional teaching, the posterior tibialis is the main cause of varus foot deformity in patients with cerebral palsy. However, the relative frequency of anterior and posterior tibialis dysfunction has only been reported with use of dynamic electromyography in relatively small series of patients, with contrasting results. The purpose of the current study was to determine the relative prevalence of posterior and anterior tibialis dysfunction with use of gait analysis in a large group of patients with cerebral palsy and varus foot deformity. METHODS: The muscular contributors to varus foot deformity in seventy-eight patients (eighty-eight feet) who had cerebral palsy were evaluated with use of computerized motion analysis and dynamic electromyography. Data also were examined to identify any relationships between the timing of varus during gait and the contributing muscle. RESULTS: The muscular contributor to varus deformity was the anterior tibialis in thirty feet, the posterior tibialis in twenty-nine feet, both the anterior tibialis and the posterior tibialis in twenty-seven feet, and another contributor in two feet. Seventy feet had varus deformity during both stance phase and swing phase. Of these seventy feet, twenty-five exhibited dysfunction of the anterior tibialis, twenty exhibited dysfunction of the posterior tibialis, and twenty-three exhibited dysfunction of both muscles. Therefore, the timing of varus was not predictive of the contributing muscle or muscles. CONCLUSIONS: The current study demonstrated a higher prevalence of anterior tibialis dysfunction, both alone and in combination with posterior tibialis dysfunction, as a contributor to pes varus in patients with pes varus and cerebral palsy than had been reported previously. Dynamic electromyography provides clinically useful information for the assessment of such patients.

Adolescent↗
PubMedDate not supplied

Radiographic and computed tomographic determination of femoral varus and torsion in the dog.

Diagnosis and quantification of femoral varus and femoral torsion using radiographs is technically challenging due to the difficulty in determining proper positioning. The purpose of this study is to describe a computed tomographic technique for determination of femoral varus and femoral torsion and to compare this technique, and standard radiography, to anatomic preparation, for the measurement of femoral varus and femoral torsion in normal dogs. Nine canine cadavers, visually and radiographically free of orthopedic disease of the hip and stifle joints, were utilized for analysis. Femoral varus was determined using a craniocaudal radiograph, a craniocaudal radiograph obtained after confirming accurate positioning using horizontal beam fluoroscopy, and computed tomography (CT). Femoral torsion (expressed as angle of version) was determined using an axial radiographic projection obtained from distal to proximal and CT. Each femur was dissected free of soft tissues, and direct determination of femoral varus and femoral torsion was performed using digital photographic images. All radiologic and photographic images were digitally measured to quantify the magnitude of femoral varus and femoral torsion. For femoral varus, no difference (P = 0.149) between the three different imaging techniques and the anatomic preparation was identified. For femoral torsion, no difference (P = 0.059) between the two imaging techniques and the anatomic preparation was identified. Well positioned radiographs and the described computed tomographic method are both as accurate as anatomic preparation for the measurement of both femoral varus and femoral torsion in normal dogs.

Animals↗
PubMed1999

Application of bone graft to the medial side of the first metatarsal head in the treatment of hallux varus.

BACKGROUND: Hallux varus deformity is not frequent, is usually acquired, and is poorly tolerated by patients. A common cause is the resection of an excessive amount of the head of the first metatarsal during an operation performed to correct a hallux valgus deformity. The purpose of this study was to evaluate the results of application of bone graft to the medial aspect of the first metatarsal head in order to restore missing bone after resection of an excessive amount of bone during a bunionectomy. METHODS: Of thirty patients who had a hallux varus deformity that was treated operatively, eight (ten feet) had bone-grafting to the medial aspect of the first metatarsal head. Six patients (seven feet) were available for evaluation at an average of 8.6 years (range, two to twenty-two years) postoperatively. The original reasons for the consultation for the hallux varus deformity were pain in the great toe, discomfort with shoewear, and the cosmetic appearance of the deformity. The pain typically was located on the medial aspect of the great toe and was caused by the pressure of the shoe; the pain usually was aggravated by walking. Preoperatively, the passive range of dorsiflexion averaged 72 degrees (range, 60 to 80 degrees); the passive range of plantar flexion, 12 degrees (range, 10 to 20 degrees); and the varus deformity, 18 degrees. RESULTS: Six of the seven feet had a satisfactory result. The pain associated with the varus deformity had disappeared in all patients. One patient was dissatisfied because of 20 degrees of valgus angulation. The passive range of dorsiflexion averaged 63 degrees (range, 60 to 70 degrees), and all patients had 10 degrees of plantar flexion. Overall, the valgus angulation of the metatarsophalangeal joint averaged 19 degrees (range, 16 to 22 degrees). There was no recurrence or persistence of the varus deformity. In three feet, the joint space was reduced, but this did not jeopardize the clinical result. CONCLUSIONS: A bone graft screwed onto the medial aspect of the metatarsal head provided a good result. This technique is indicated when the varus deformity is related to a previous resection of an excessive amount of bone during a bunionectomy and when the deformity is passively reducible to neutral.

Adult↗