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PubMedDate not supplied

[Corrective osteotomy in the treatment of degenerative changes in the knee joint].

Angular deformity of the knee can be corrected by high tibial osteotomy or distal femoral osteotomy. In this research we have analysed effects of corrective osteotomy in knees with varus or valgus deformity. In this research we present a long-term evaluation of 67 patients older than 40 with angular deformity of the knee in which high tibial osteotomy and distal femoral osteotomy were performed at the Department of Orthopaedic Surgery, School of Medicine, University of Zagreb, in the period 1982-1992. Operation was performed bilaterally in 14 patients. There were 66 knees with varus deformity and 15 with valgus deformity out of a total of 81 knees. The most patients with valgus deformity were corrected by supracondylar osteotomy and the most with varus deformity by osteotomy of proximal tibia. The average preoperative duration of symptoms was 6.1 years. The average age was 57.5 at the moment of operation. The mean follow-up was 7 years (range 3-13 years). We assessed the degree of arthrosis according to Ahlböck in five-grade scale. The mean arthrosis was 2.0 preoperatively, 2.2 postoperatively and 2.6 at the last follow-up examination. Although the patients with valgus deformity had smaller degree of arthrosis preoperatively than patients with varus deformity, arthrosis developed equally in both groups despite the fact that the operation was performed. We measured joint tilt according to Shoja and Insall. The patients with varus deformity had joint tilt 7 degrees before operation, -4.3 degrees after operation and -2.4 degrees at the last control. The patients with varus deformity had femurotibial angle of 185 degrees preoperatively, 173 degrees postoperatively, and 175 degrees at the last follow-up examination. The average revarisation of 2 degrees occurred despite overcorrection. The patients with valgus deformity had femurotibial angle of 164 degrees preoperatively, of 178 degrees postoperatively and of 180 degrees at the last follow-up examination. Revarisation progressed 2 degrees on average after varisation osteotomy was performed in the knees with valgus deformity. There was no statistically significant correlation between pain and femurotibial angle and pain and degree of arthrosis preoperatively, postoperatively and at the last follow-up examination. The patients were assessed according to the system developed at the Hospital for Special Surgery (HSS). The mean preoperative HSS score was 2.91 (2.82 varus and 3.33 valgus deformity), and postoperative 4.47 (4.42 varus and 4.47 valgus). The mean score at the last follow-up evaluation was 4.05 (varus 4.03 and valgus 4.13). The patients assessed the improvement themselves and it was 1 to 14 (6.1) years. Although the indications for aloarthroplasty of the knee are more frequent nowadays, the authors recommend not to forget corrective osteotomy in the treatment of angular deformity of the knee with osteoarthritis.

Female↗

PubMed2001

High tibial osteotomy in knee instability: the rationale of treatment and early results.

We treated 14 patients having knee instability and varus alignment with tibial osteotomy with or without ligament reconstruction. Five patients with varus angulated anterior cruciate deficiency (double varus) were treated with single-stage closed-wedge tibial osteotomy and anterior cruciate ligament reconstruction. The remaining nine patients had varying amount of posterior cruciate and postero-lateral corner ligament injuries with varus angulation (triple varus); six of these patients had a ligament reconstruction using the Ligament Advanced Reconstruction System ligament with tibial osteotomy (intra-articular--posterior cruciate ligament/extra-articular--postero-lateral corner reconstruction), while the remaining three had a tibial osteotomy without a ligament reconstruction. Four of the nine patients with triple varus had open-wedge tibial osteotomy, and the remaining five had closed-wedge tibial osteotomy. The mean time interval between injury and index surgery of an osteotomy and ligament surgery was 8.3 years (range 1-20 years). At a mean follow-up of 2.8 years after tibial osteotomy, 12 knees (86%) were stable and eliminated of giving way while the remaining 2 were unstable. In one of these patients the result was compromised with severe infection, while in another there was combined cruciate ligament deficiency with postero-lateral corner ligament deficiency. Thirteen (93%) of the patients were able to participate in light recreational activities. None of these patients could return to competitive sports. Five (35%) continued to have pain of varying degree. The mean Cincinnati Knee Score improved from a mean preoperative of 53 (range 40-58) to a mean postoperative of 74 (range 58-82). Accordingly, there were two poor, four fair and eight good results. In-patients with triple-varus, open-wedge tibial osteotomy had better scores than those with closed-wedge procedure. The results of this series are encouraging, and we recommend a high tibial osteotomy along with ligament reconstruction in these complex injuries with varus alignment.

Adolescent↗

PubMed2004

A two- stage surgery for severe femoral neck deformity due to fibrous dysplasia: a case report.

Various kinds of surgical treatments have been reported for varus deformity of the proximal femur due to fibrous dysplasia. We report a case of two-stage corrective osteotomy for severe varus-retroversion deformity of the femoral neck due to monostotic fibrous dysplasia. The patient was an 18 year-old man. On initial examination, the spina malleollar distance was 88 cm on the right side and 83 cm on the left. Plain radiography showed prominent varus deformity of his left proximal femur. The morphology was 130 degrees on the right side and 85 degrees on the left. Computed tomography revealed 60 degree retroversion of the femoral neck. A two-stage surgery was performed, consisting of curettage and bone grafting followed by corrective osteotomy 16 months later. A 55 degree valgus osteotomy was performed in the subtrochanteric region. After osteotomy and 40 degree internal rotation of the shaft, a 130 degree angle plate was used for osteosynthesis. Postoperative radiological examination showed a morphology of 140 degrees and computed tomography revealed a 20 degree retroversion of the femoral neck. No recurrence or varus deformity was seen at four years after surgery. Although the leg length discrepancy was 2.5 cm, the patient had no difficulty in one foot standing and no restriction of ADL (activity of daily living). The well-known progressive varus Shepherd's crook deformity in the polyostotic form of fibrous dysphasia is associated with limb shortening, limping, and occasionally chronic fatigue fractures with disabling pain. Various kinds of surgical treatments have been reported for this type of varus deformity. Curettage and bone grafting is one of the most common and simple treatments. However, this method often gives bad results as the grafted bones are absorbed and that the progress of varus deformity van not to be prevented. We report a case of two-stage corrective osteomy forsevere varus-retroversion deformity of the femoral neck due to monostotic fibrous dysplasia.

Activities of Daily Living↗

PubMed2002

[Posterior plantar release in the treatment of congenital pes equinovarus].

PURPOSE OF THE STUDY: The study present one of the possible surgical strategies of the therapy of the congenital varus club foot in the youngest patients, most frequently in infants and toddlers. This strategy is used in rigid varus club feet of Dimegli Group 1 and 2. It is possible also to use it in the rebelling varus club feet, however, the reconstruction is more difficult in these cases. MATERIAL: In the period of 1983-2000 the method of posteroplantar release was used 93 times, of which 59 times as a primary surgery and 34 times during revision surgery. The youngest patients were 8 months old, the oldest children were during the revision surgery 8 years old. METHODS: In case of the persisting adduction and varus deformity after conservative therapy of the congenital varus club foot first of all plantar release of the forefoot was performed and subsequently from a slightly oblique longitudinal approach a radical posterior capsulotomy with the lengthening of the Achilles tendon, by means of talocalcanear reduction with transfixation by K-wires. Plaster of Paris is applied during 3 months after the operation with the replacement of correction plaster casts after each 3-4 weeks. The shortest interval after the surgery was 9 months. The group comprised 47 patients (in total 62 feet). RESULTS: The followed-up group of patients was examined clinically with the simultaneous evaluation of radiographs. Excellent result--anatomical position of the foot was obtained in 68%, good result was recorded in 26%. Poor result was recorded in 2 patients in bilateral varus club foot with meningomyelocele. Radiographs showed during the evaluation of the mutual position of talus and calcaneus an increase of the angle in the lateral projection on average by 12 degrees, in anteroposterior projection by 10 degrees. DISCUSSION: The numbers of patients, indication and results of the followed-up group of patients are comporable with literary data. Excellent and good results of the posteroplantar release are even better than those of the complete release included in the literatury studies. The procedure starting by the release first the plantar structures is to a certain extent an original strategy. Usually after the operation on posterior structures the plantar release was used only subsequently in case of persisting adduction and varus deformity of the forefoot. Surgery even in case of a rebelling defect allows to use in future subsequent surgical procedures which is problematic after a complete release where there occurs in a certain percentage also necrosis of talus and calcaneus. CONCLUSION: Posteroplantar release is one of the possible surgical procedures in the solution of the rigid congenital varus club foot. Although the operation may be included in the so called procedure of small steps in most patients it solves finally the defect.

Child, Preschool↗

PubMed2006

Using flexible nails to improve stabilization of proximal femur fractures in adolescents.

Intramedullary fixation as a treatment for adolescent femur fractures has increased in popularity. We investigated the varus stability of 3 fixation techniques--the standard 2-nail configuration (2 retrograde nails), a 3-nail configuration (standard 2-nail configuration plus 1 antegrade nail), and a retrograde/antegrade 2-nail configuration--in synthetic femurs with 2 simulated fracture patterns (transverse, butterfly). A varus moment was applied to the specimens until 20 degrees of varus angulation was obtained. The varus angular stiffness of the construct defined varus stability. The 3-nail configuration had the most varus angular stiffness with both fracture patterns. The varus stability of the 3-nail configuration was statistically higher than that of the standard 2-nail configuration with the transverse fracture pattern only. Adding 1 antegrade nail to 2 retrograde nails significantly increased resistance to varus deformity of reduced proximal-third transverse femur fractures in the synthetic femur model.

Adolescent↗

PubMed1997

[Post-traumatic epiphysiodesis of the distal end of the tibia in children].

PURPOSE OF THE STUDY: Thirteen distal traumatic epiphyseal closures of the lower end of the tibia are studied. A bony bridge resection was performed in nine cases. The aim of this study was to define the kind of injury that drives to epiphysiodesis in this localisation, and secondly to define the factors that may influence the results of de-epiphysiodesis. MATERIALS AND METHODS: One hundred and eighty-eight children were hospitalized between 1981 and 1995 for the treatment of a fracture of the lower end of the tibia. Six epiphysiodesis followed a Mac Farland lesion. Six epiphysiodesis followed a Salter and Harris Type-II injury. One epiphysiodesis followed a triplane fracture. The diagnostic of epiphysiodesis was performed at an average of 12 months after injury. The bony bridge interested less than 50 per cent of the growth plate in all cases. There was a varus deformation between 7 degrees and 20 degrees in six cases (average 13.8 per cent). Ten surgical procedures were performed: one fibular bi-focal epiphysiodesis and nine tibial de-epiphysiodesis including a resection of the bony bridge filled with acrylic cement. Two children were not operated because they were close to the end of growth and there was no varus deformation. One child was not reviewed. RESULTS: There was a significant correlation between the children age and the importance of the ankle varus deformation. The younger the children were and the more important the varus deformation was. Only three de-epiphysiodesis had a good clinical and radiological result. In five cases, a second surgical procedure was necessary. Fibular bi-focal epiphysiodesis gave a good clinical result. DISCUSSION: In this location, Harris and Salter type II fractures may have a poor prognosis for growth if the injury occurred with high energy. Varus deformation is a common way to discover epiphysiodesis in this location. There was no correlation between the children age and the result of the de-epiphysiodesis, and between the delay since injury and the de-epiphysiodesis result. There was a correlation between the result and the presence of a varus dexasation in the ankle. The more important the varus was and the poorer the result was. CONCLUSION: Mac Farland lesion and Salter and Harris type II lesion drive to epiphysiodesis more often than any other distal tibial fracture. Varus desaxation is more important in younger children and seems to determine de-epiphysiodesis results. But over all, de-epiphysiodesis has a poor prognosis in more than 60 per cent of cases.

Adolescent↗

PubMed2005

Graft reconstruction of the interosseous membrane in conjunction with metallic radial head replacement: a cadaveric study.

PURPOSE: Longitudinal radioulnar dissociation (Essex-Lopresti injury) occurs when traumatic axial loading through the wrist disrupts the interosseous membrane (IOM) of the forearm and fractures the radial head. Proximal migration of the radius results in an ulnar-positive wrist, which can lead to painful ulnar-sided wrist degeneration and distal radioulnar joint instability. The purpose of this study was to measure the ability of an IOM reconstruction used in combination with a metal prosthetic radial head implant to reduce distal ulnar forces in a cadaveric model. The effects of varying the initial graft pretension on distal ulnar force were also studied. METHODS: Twelve fresh frozen and thawed cadaveric forearms had a miniature load cell installed to record force in the distal ulna as the wrist was loaded axially to 134 N of compression force in neutral rotation. Intact forearms were tested first with the elbow in valgus and varus alignments. Loading tests were repeated after (1) insertion of a metal radial head implant that restored radius anatomic length, (2) excision of the IOM (with a radial head implant), and (3) reconstruction of the IOM using a palmaris longus tendon autograft (with a radial head implant). The implant then was removed and loading tests were repeated using 3 levels of initial graft pretension. RESULTS: Mean distal ulnar forces with an intact forearm were 23% of applied wrist force in the varus alignment and 12% in the valgus alignment. Mean force levels after insertion of the implant were 18% (varus) and 13% (valgus); these were not significantly different from corresponding values for the intact forearm. Mean force levels after section of the IOM were 30% (varus) and 14% (valgus); these were not significantly different from corresponding values for the intact forearm (varus and valgus) but the mean for varus was significantly greater than the corresponding value with an implant. After IOM reconstruction with a palmaris longus tendon tensioned to 22 N mean distal ulnar forces were 8% (varus) and 7% (valgus); these means were significantly less than the corresponding values for all prior test conditions. With the radial head removed increasing the level of graft pretension reduced significantly mean distal ulnar force. CONCLUSIONS: With the IOM resected insertion of a metal radial head implant alone did not reduce distal ulnar forces to intact forearm levels. When an IOM reconstruction was performed in combination with the implant mean distal ulnar force was reduced significantly to a level below that for the intact forearm. Applying pretension to the graft displaced the radius distally thereby making the wrist more ulnar negative and reducing distal ulnar force. Our results suggest that an IOM reconstruction used in combination with a metal radial head implant theoretically could help reduce distal ulnar impaction in an Essex-Lopresti injury.

Aged↗

PubMedDate not supplied

Elbow joint laxity after experimental radial head excision and lateral collateral ligament rupture: efficacy of prosthetic replacement and ligament repair.

The objectives of this experimental study were to investigate the effect of radial head excision and lateral collateral ligament (LCL) division on elbow joint laxity and to determine the efficacy of radial head prosthetic replacement and LCL repair. Valgus, varus, internal rotation, and external rotation of the ulna were measured during passive flexion-extension and application of a 0.75-Nm torque in 6 intact cadaveric elbows and after (1) either excision of the radial head or division of the LCL, (2) removal of both constraints, (3) isolated radial head prosthetic replacement, (4) isolated LCL repair, and (5) radial head replacement combined with LCL repair. Isolated radial head excision increased varus (mean, 4.8 degrees) and external rotatory laxity (mean, 7.1 degrees), as did isolated LCL division (mean, 14.1 degrees for varus; mean, 14.7 degrees for external rotation). After removal of both constraints, varus and external rotatory laxities were increased by 19.0 degrees and 20.1 degrees, respectively, compared with the intact specimens. Isolated radial head replacement reduced mean varus laxity to 14.6 degrees and mean external rotatory laxity to 14.8 degrees. Isolated LCL repair normalized varus laxity but resulted in a 2.9 degrees increase in external rotatory laxity. The combined procedures restored laxity completely. The radial head is a constraint to varus and external rotation in the elbow joint, functioning by maintaining tension in the LCL. Still, removal of both constraints induces severe laxity, and in this case, prosthetic replacement may substitute for the constraining capacity of the native radial head. The combination of LCL repair and radial head replacement restores laxity completely, but an isolated LCL repair performs almost as well, probably by compensating for the ligamentous tension lost from radial head excision.

Adult↗

PubMed1991

A relationship between stem orientation and function following total hip arthroplasty.

A retrospective gait analysis of patients with cemented Charnley-Mueller total hip arthroplasties was conducted to determine if functional differences exist between patients with femoral stems placed in varus and valgus orientations. Twenty patients and ten normals were studied using gait analysis to quantify joint motion and moments during level walking. In addition, a radiographic analysis of stem placement and mechanics of the reconstructed hip was performed on the total hip patients. All patients selected for the study had excellent clinical results on the basis of a score of 95 or better on the Harris hip rating form. The patients were divided into two subgroupings on the basis of stem orientation. A valgus group was defined as having a valgus stem orientation relative to the femoral shaft, with the femoral head-shaft offset shortened by 5 mm or greater compared to the contralateral unoperated hip, while the varus group was defined on the basis of having a varus stem orientation relative to the femoral shaft, with the femoral head-shaft offset restored to normal or greater than normal. A difference in gait was found between the varus and valgus patient groupings. The varus group had abnormal gait characteristics in the range of hip motion, the flexion-extension moments at the hip, and stride length. The patients in the valgus group had statistically normal gait. The differences in the gait characteristics were interpreted as an attempt to alter forces on the hip joint for patients in the varus group. These alterations were possibly an early indication of a subtle adaptation in patients with varus-placed femoral stems since, historically, a greater percentage of the patients in this configuration, retrospectively, go on to mechanical failures.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1997

Stiffness of trabecular bone of the tibial plateau in patients with rheumatoid arthritis of the knee.

Stiffness of subchondral proximal tibial trabecular bone is a factor in the stability of prostheses implanted into that bone. The stiffness of trabecular bone in osteoarthritis (OA) has been documented. Trabecular bone in rheumatoid arthritis (RA) is osteopenic in numerous sites and morphologically abnormal in the proximal tibia. Reliable data on proximal tibial bone in RA are lacking, although 1 study failed to identify abnormalities. The purposes of this study were (1) to document the stiffness of the proximal tibial cancellous bone in patients with RA, (2) to determine the effect of angular deformity on bone stiffness in rheumatoid patients, and (3) to compare RA stiffness values with those in published reports for OA. Fifteen tibial plateau were obtained from patients with RA during surgery. Each plateau was horizontally seated in a mold and covered with cement. The plateau was divided into 6 regions, which were used to facilitate comparison between specimens and the existing literature. Indentation tests were conducted with a 4-mm-diameter cylindrical indentor controlled by an MTS machine. The indentor descended at a rate of 2 mm/min to a maximum depth of 1.0 mm; load and displacement data were digitally recorded. Stiffness was calculated from the slope of the linear region of the curve using best-fit linear regression. Where varus deformity was present, stiffness in the medial plateau was higher overall than for the other compartment; whereas in the case of valgus deformity, stiffness of the lateral side was significantly higher (P < .05 for each observation). In comparison to older normal specimens, both the medial compartment of the varus RA specimens (P < .01) and the posterolateral compartment of the valgus RA specimens (P < .01) had significantly lower stiffness. Comparison with OA specimens showed that in varus RA, the posteromedial region had significantly lower stiffness than in varus OA at the same site (P < .01). In valgus RA, the lateral region had significantly lower stiffness than in valgus OA at the same site (P < .01). The mean stiffness ratio of the valgus RA was significantly (P < .01) altered from normal, and for the varus RA, it was significantly (P < .01) different from normal posteriorly. The stiffness ratios for the varus RA were significantly (P < .01) different from those for varus OA; there was no difference between valgus RA and valgus OA. It is concluded that RA affected bone has significantly lower stiffness than normal and osteoarthritic bone. The loaded plateau is stiffer than the unloaded plateau in angular deformity, but is still less stiff than normal bone and osteoarthritic plateaus with corresponding deformities.

Arthritis, Rheumatoid↗

PubMed2006

A morphometrical study of the medullary cavity of the ulna referred to intramedullary nailing.

Intramedullary fixation is preferred for osteosynthesis in the case of long bone fractures; but the problem of the nails' adjustment to the anatomical needs remains. About 80 cadaveric ulnae were examined to elucidate the curvature of the medullary cavity, the point of varus angulation, the thickness of the radial and ulnar cortical bone and the diameter of the medullary cavity at that point. Furthermore, the point of varus angulation of the posterior border was compared to that of the medullary cavity, to evaluate if it allows any conclusion to the curvature of the medullary cavity. The point of varus angulation of the medullary cavity ranged from 45 to 110 mm (mean 71.02), its angle from 4 to 13.5 grade (mean 8.95). At this point, the thickness of the cortical bone on the radial side was between 2.5 and 7 mm (mean 4.44) and ulnar between 2 and 8 mm (mean 4.37). The diameter ranged from 4 to 10.5 mm (mean 6.96). The point of varus angulation of the posterior border was between 65 and 110 mm (mean 85.88) and differs from that of the medullary cavity observed between 45 and 110 mm (mean 71.02). The point of varus angulation of the posterior border and the medullary cavity differs from 1 to 60 mm and it is found in most cases to be more distal than the point of varus angulation of the medullary cavity so the palpable posterior border allows no reliable conclusion of the curvature of the medullary cavity.

Adult↗

PubMed1998

The effect of intersegmental knee moments on patellofemoral contact mechanics in cycling.

The aim of this study was to evaluate the effect of bicycle pedal design on the mechanics of the patellofemoral joint. Previous research determined that for certain riders the non-driving varus and internal knee moments could be reduced by switching from fixed to free floating pedals (Ruby and Hull, 1993). It was postulated that the presence of varus and internal knee moments during fixed pedal cycling may adversely affect patellofemoral joint contact mechanics which could lead to the development of anterior knee pain. To investigate the effect of pedal design the hypothesis that varus and internal intersegmental knee moments significantly increase patellofemoral contact pressure, contact area and contact force was tested. To test this hypothesis cycling loads were simulated in vitro using a six-degree-of-freedom load application system (LAS). Using the LAS, varus moments ranging from 0-20 Nm and internal knee moments ranging from 0-10 Nm were applied simultaneously with quadriceps force at knee flexion angles of 60 and 90 degrees. Patellofemoral contact patterns were measured using pressure sensitive film. An applied 10 Nm internal moment significantly increased both contact area by 16% and contact force by 22% at 90 of flexion. The application of a 20 Nm varus moment modestly yet significantly increased contact area by 6% and contact force by 5%. When applied in combination, varus and internal knee moments increased contact area and force by as much as 29% and 28% respectively. The mean contact pressure was not significantly increased by either of the two moments. The results suggest that non-driving intersegmental knee moments subject the patellofemoral joint to loads and contact patterns which may accelerate the development of chondromalacia.

Aged↗

PubMed2006

[Axial lower limb alignment and knee geometry in patients with osteoarthritis of the knee].

PURPOSE OF THE STUDY: We conducted a retrospective radiographic study to identify and quantify medial and lateral misalignments in candidates for total knee arthroplasty. MATERIAL AND METHODS: We studied a discontinuous series of 101 patients (164 knees) among candidates for total knee arthroplasty seen between 1990 and 2002. We selected a random sample for study. Exclusion criteria were any history of fracture, surgical treatment, rheumatoid disease, or congenital disorder. A first group of 136 genu varum knees was identified in 82 patients (mean age 72 years, mean weight 79 kg). A second group of 28 genu valgum knees was identified in 19 patients (mean age 67 years, mean weight 71 kg). The standard radiograms were digitalized for semi-automatic measurements using the Metros software. We recorded overall deformation, femoral valgus, tibial varus, HKA angle, HKS angle (mechanical/anatomic axis of the femur) and angle C (horizontal inclination of the ankle to the ground). All measures were compared between each other for each patient to search for relations. RESULTS: In the genu varum group (136 knees), mean overall deformation was 9 degrees , mainly due to tibial misalignment (5.5 degrees ) with a 1 degrees femoral valgus component. The HKS angle was 6.3 degrees , and lateral joint gap 4.3 degrees ; the C angle was 4 degrees . Overall varus followed tibial varus (p<0.01). Ankle inclination followed tibial varus (p<0.01). In the genu valgum group (28 knees), overall deformation was 4.2 degrees , mainly due to femoral misalignment (5.6 degrees) with 1 degrees tibial varus and a medial joint gap of 2 degrees . The HKS angle was 4.7 degrees and the mean C angle -4 degrees . Overall valgus was related to femoral valgus (p<0.001). Tibial varus was greater with greater femoral valgus (p<0.01). In both groups, the HKS angle was smaller with greater femoral valgus. DISCUSSION: Semi-automatic measurements on digitalized films enabled excellent reproducibility. Causes of error were related to limb rotation at acquisition. This study showed that genu varum worsens because of tibial wear followed by ligament distension, while for genu valgum, worsening predominantly results from femoral wear. The ankle joint line was nearly horizontal in one-third of the limbs, even when there was a major misalignment of the lower limb. The HKS angle was quite variable in both morphotypes, but was smaller with greater femoral valgus in both groups. CONCLUSION: Measuring all components involved in medial and lateral knee misalignment is very useful for understanding the morphotype of each individual knee before performing osteotomy or implanting a knee prosthesis.

Aged↗

PubMed2001

Association among neuromuscular and anatomic measures for patients with knee osteoarthritis.

OBJECTIVE: To investigate neuromuscular and anatomic factors involved in varus gonarthrosis by identifying measures associated with degenerative changes. DESIGN: Descriptive study. Individual measures that explained substantial portions of the variability in ratings of knee joint-degenerative changes in patients with knee medial compartment osteoarthritis. SETTING: Outpatient orthopedic clinic and biomechanics and muscular assessment laboratory. PATIENTS: Volunteer sample of 20 subjects (age range, 59 +/- 9 yr) with no history of neurologic disease. INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: We assessed degenerative changes, varus alignment, standing balance, and knee proprioception. Weight-bearing radiographs were used to assess the extent of degenerative changes and the degree of varus alignment. Single-limb standing balance control was assessed through tests performed on a force platform. Knee proprioception was assessed with an isokinetic dynamometer, using a joint angle replication test. RESULTS: Forward-stepwise multiple linear regression indicated that the extent of degenerative changes could be best predicted from a linear combination of the independent variables, varus alignment, and standing balance (R =.80, F(2,17) = 14.81, p =.0002). Sixty-four percent of the variability in ratings of degenerative changes was explained by alignment and standing balance measures (37% by varus alignment, 27% by standing balance). Alignment and balance measures were poorly correlated (r =.12, p =.63), further suggesting that they provided different information about gonarthrosis. CONCLUSIONS: Although varus alignment is widely accepted as a clinically important factor in gonarthrosis, and is the focus of many treatment efforts, our results suggest that objective measures of standing balance are also important. As a result, the potential impact of rehabilitation to improve the control of standing balance should be further evaluated in this patient population.

Biomechanical Phenomena↗

PubMed1996

Twenty years' followup of intertrochanteric osteotomy for treatment of the dysplastic hip.

A followup study of more than 15 years of intertrochanteric osteotomy for osteoarthrosis of the dysplastic hip was performed in 52 hips of 42 patients with varus osteotomy and in 58 hips of 53 patients with valgus osteotomy. Varus osteotomy was indicated for predegenerative or early degenerative stages of osteoarthrosis, and valgus osteotomy was indicated for progressive or end stage disease. The average age at time of varus and valgus osteotomies was 25 and 37 years, respectively, and the average followup period was 21 and 20 years, respectively. Using Kaplan-Meier's method (end point, Harris Hip Score < 70 points or salvage operation), the 10- and 15-year survival rates for varus osteotomy were 89% and 87% and for valgus osteotomy were 66% and 38%, respectively. Radiographic measurements of the postoperative acetabular head index and center edge angle in varus osteotomy were better in the group with good results than those in the group with poor results. There were no differences in radiographic measurements between the group with good results and the group with poor results of valgus osteotomy. Intertrochanteric varus and valgus osteotomy delayed the need for total hip arthroplasty in young patients with osteoarthrosis of the dysplastic hip.

Adolescent↗

PubMedDate not supplied

Proximal femoral physis shear in slipped capital femoral epiphysis--a finite element study.

The following finite element study was conducted to determine whether increased body weight, femoral retroversion, and varus hip loading could sufficiently raise physeal shear strains and stresses above the yield point and predispose an adolescent hip to a slip. A computer tomography scan of a 13-year-old child with slipped capital femoral epiphysis was used to generate a solid model of the proximal femur and physis. The model was parameterized using 3-dimensional software to generate three difference angles of femoral neck version-neutral, 15 degrees retroversion, and 15 degrees anteversion. Loads of 2.7 times body weight in a 46- and 86-kg child were applied to the proximal femur to model stance on one leg. In addition, the loading vector was reoriented at various degrees of varus to study the effect of varus loading on physis shear. The results demonstrated that physis stress, strain, and displacement increased with greater body weight, retroversion, and varus displacement of the loading vector. Physis shear strain in hips with a combination of varus loading and femoral neck retroversion exceeded the reported ultimate strain values for cartilaginous soft tissues. The finite element models suggest that in an overweight child, the combination of retroversion and varus hip load may be sufficient to increase physeal strains above the yield point and result in a slip.

Adolescent↗

PubMed2001

Effects of radial head excision and distal radial shortening on load-sharing in cadaver forearms.

BACKGROUND: The present study was performed to measure changes in radioulnar load-sharing in the cadaveric forearm following two orthopaedic surgical procedures that often have varying results: radial head excision and distal radial shortening. A better understanding of the biomechanical consequences of those procedures could aid surgeons in obtaining a more satisfactory clinical outcome. METHODS: Miniature load-cells were inserted into the proximal part of the radius and the distal part of the ulna in twenty fresh-frozen cadaveric forearms. Load-cell forces, radial head displacement relative to the capitellum, and local tension within the central band of the interosseous membrane were measured simultaneously as the wrist was loaded to 133.5 N in neutral pronation-supination and neutral radioulnar deviation. Testing was repeated after incremental distal radial shortening and after removal of the radial head. RESULTS: With the elbow flexed to 90 degrees and in valgus alignment (the radial head in contact with the capitellum), the mean force in the distal part of the ulna was 7.1% of the applied wrist force and the mean force in the interosseous membrane was 4.0%. With the elbow in varus alignment (a mean initial gap of 1.97 mm between the radial head and the capitellum), the respective mean values were 27.9% and 51.2%. After excision of the radial head, the mean force in the distal part of the ulna increased to 42.4% of the applied wrist force and the mean force in the interosseous membrane increased to 58.8%, in both varus and valgus elbow alignment. The mean distal ulnar force increased with progressive distal radial shortening in both varus and valgus elbow alignment; after 6 mm of radial shortening, the distal ulnar force averaged 92.4% (in varus alignment) and 60.9% (in valgus alignment). Equal distal load-sharing between the radius and ulna occurred after approximately 5 mm of radial shortening with the elbow in valgus alignment and after approximately 2 mm of radial shortening with the elbow in varus alignment. In valgus alignment, the force in the interosseous membrane was negligible after all degrees of radial shortening; in varus alignment, the mean force in the interosseous membrane decreased from 51.2% (0 mm of distal radial shortening) to 0% (6 mm of distal radial shortening) because of progressive slackening of the interosseous membrane. CONCLUSIONS: Radial head excision shifted the applied wrist force that normally would be transmitted to the elbow, through radial head-capitellar contact, to the interosseous membrane. The resulting proximal radial displacement created an ulnar-positive wrist and increased distal ulnar loading. Radial shortening and ulnar lengthening procedures have been designed to shift the applied wrist force from the distal part of the radius to the distal part of the ulna; it is commonly assumed that these procedures have equivalent biomechanical effects. We found that radial shortening resulted in slackening of the interosseous membrane, thereby negating its ability to transmit load through the forearm. Slackening of the interosseous membrane would not be expected with distal ulnar lengthening procedures. CLINICAL RELEVANCE: When the radial head has been fractured or excised, the mechanical status of the interosseous membrane is critical to the load-sharing process. If the interosseous membrane remains intact, distal ulnar loads will be limited to less than half of the applied wrist force; if the interosseous membrane has been damaged, nearly the entire applied wrist force will be shifted to the ulna. The amount of radial shortening or ulnar lengthening performed at the time of surgery during joint-leveling procedures has been largely empirical. We found that distal ulnar load increased by approximately 10% for each millimeter of radial shortening.

Aged↗

PubMed2005

Outcome of hemiepiphyseal stapling for late-onset tibia vara.

BACKGROUND: The results of hemiepiphysiodesis for the treatment of late-onset tibia vara have been reported to be favorable, but the technique requires careful timing and an accurate estimation of skeletal age. Hemiepiphyseal stapling does not require a careful estimation of skeletal age, and it has been reported to yield good results with low morbidity. However, we are not aware of any study evaluating the intermediate-term radiographic results or complications of this procedure. METHODS: Twenty-six patients with thirty-three extremities with late-onset tibia vara were treated with proximal tibial hemiepiphyseal stapling. Fourteen extremities had substantial concomitant distal femoral varus and also had hemiepiphyseal stapling of the distal part of the femur. Eighteen patients (twenty-three involved extremities) had juvenileonset tibia vara and eight patients (ten involved extremities) had adolescent-onset tibia vara. The mean age at the time of stapling was 11.8 years. The mean duration of follow-up was 3.8 years. We reviewed standardized standing radiographs to determine the mechanical axis deviation, the medial proximal tibial angle, the lateral distal femoral angle, and the zone of the knee through which the mechanical axis passed. RESULTS: The mean mechanical axis deviation improved from 58 mm (range, 27 to 157 mm) preoperatively to 22 mm (range, -33 to 117 mm) at the time of the last follow-up, and the mean medial proximal tibial angle improved from 77 degrees (range, 50 degrees to 85 degrees ) to 85 degrees (range, 48 degrees to 95 degrees ). In the fourteen lower extremities in which distal femoral hemiepiphyseal stapling was performed, the mean lateral distal femoral angle improved from 96 degrees (range, 92 degrees to 100 degrees ) to 86 degrees (range, 79 degrees to 97 degrees ). At the time of the final follow-up, seven extremities were considered to be in moderate varus; four, in mild varus; twenty, in normal alignment; and two, in valgus. No differences in radiographic outcome were noted between the juvenile and adolescent forms of tibia vara. Only one of the four extremities with severe preoperative varus was corrected to normal alignment; the remaining three were left with moderate varus. CONCLUSIONS: Hemiepiphyseal stapling of the lateral aspect of the proximal tibial physis and, as needed, the lateral aspect of the distal femoral physis is safe and effective in children with late-onset tibia vara if the physes are sufficiently open and the varus deformity is mild to moderate. Hemiepiphyseal stapling is particularly effective in patients who are ten years of age or younger. LEVEL OF EVIDENCE: Therapeutic Level IV.

Adolescent↗