Elevation of medial tibial condyle for severe tibia vara

Clinical and radiological evidence of knee instability was used as criteria for elevation of medial tibial condyle in severe tibia vara. Restoration of tension to the exposed medial collateral ligament was used as a guide for the required amount of elevation. A second-stage proximal tibial osteotomy was performed later for correction of the remaining varus deformity. External fixators were used in all instances. Elevation of the medial tibial condyle is indicated in severe tibia vara with arrest of the medial tibial physis, in which more than a 10 degrees difference exists between valgus and varus stress radiographs with the knee in extension as compared with an opposite normal knee.     

Tibia Vara Affects the Aspect Ratio of Tibial Resected Surface in Female Japanese Patients Undergoing TKA

Background

Tibia vara seen in Japanese patients reportedly influences the tibial component alignment when performing TKA. However, it is unclear whether tibia vara affects the component position and size selection.

Questions/purposes

We therefore determined (1) the amount of medial tibial bow, (2) whether the tibia vara influences the aspect ratio of the tibial resected surface in aligning the tibial component with the tibial shaft axis, and (3) whether currently available tibial components fit the shapes of resected proximal tibias in terms of aspect ratio.

Methods

We measured the tibia vara angle (TVA), proximal varus angle (PVA), and the mediolateral and middle AP dimensions of the resected surface using three-dimensional preoperative planning software in 90 knees of 74 female patients with varus osteoarthritis. We determined the correlations of the aspect ratio with TVA or PVA and compared the aspect ratios to those of five prosthesis designs.

Results

The mean TVA and PVA were 0.6° and 2.0°, respectively. The aspect ratio negatively correlated with both TVA and PVA (r = −0.53 and −0.55, respectively). The mean aspect ratio of the resected surface was 1.48 but gradually decreased with increasing AP dimension, whereas four of the five prostheses had a constant aspect ratio.

Conclusions

The aspect ratio of resected tibial surface was inversely correlated to the degree of tibia vara, and currently available prosthesis designs do not fit well to the resected surface in terms of aspect ratio.

Clinical Relevance

The design of a tibial component with a smaller aspect ratio could be developed to obtain better bone coverage in Japanese patients.     

Femoral deformity in tibia vara

BACKGROUND: Previous studies have suggested that compensatory valgus deformity of the femur is common in patients with tibia vara, or Blount disease. The availability and routine use of standing long-cassette radiographs of the lower extremities to assess angular deformities has allowed quantitative evaluation of this hypothesis. METHODS: The cases of all patients with tibia vara, two years of age or older, seen at our institution prior to treatment, over a thirteen-year period, were reviewed. Seventy-three patients with a total of 109 involved lower limbs were identified and were classified as having either infantile tibia vara (thirty-seven patients with fifty-six involved limbs) or late-onset tibia vara (thirty-six patients with fifty-three involved limbs). Standardized standing radiographs of the lower extremity were examined to assess the deformity at the distal part of the femur and the proximal part of the tibia by measuring the lateral distal femoral angle and the medial proximal tibial angle. RESULTS: The distal part of the femur in the children with infantile tibia vara either was normal or had mild varus deformity, with a mean lateral distal femoral angle of 97 degrees (range, 82 degrees to 129 degrees). The mean medial proximal tibial angle in these children was 72 degrees (range, 32 degrees to 84 degrees). Older children with infantile tibia vara were noted to have little distal femoral deformity, with no more than 4 degrees of valgus compared with either normal values or the contralateral, normal limb. Children with late-onset tibia vara had a mean lateral distal femoral angle of 93 degrees (range, 82 degrees to 110 degrees) and a mean medial proximal tibial angle of 73 degrees (range, 52 degrees to 84 degrees). On the average, the varus deformity of the distal part of the femur constituted 30% (6 degrees of 20 degrees) of the genu varum deformity in these patients. CONCLUSIONS: Patients with infantile tibia vara most commonly had normal alignment of the distal parts of the femora; substantial valgus deformity was not observed. Distal femoral varus constituted a substantial portion of the genu varum in children with late-onset disease. When correction of late-onset tibia vara is planned, the surgeon should be aware of the possibility that distal femoral varus is a substantial component of the deformity.     

Rekonstruktion der Tibiadiaphyse mittels Tibiakopftransfer auf die proximale Fibula

Osteoarthritis of the knee is often diagnosed in the orthopedic trauma practice. One major cause is axial deformity with overload. In the case presented here osteomyelitis of the tibial diaphysis developed in childhood. Surgical treatment consisted of resection of the middle tibial third and transferring the tibial head onto the proximal fibula. In this way it was possible to eradicate the osteomyelitis of the lower leg and to achieve osseous consolidation between the tibia and fibula. Despite the significant shortening of the lower limb and the varus axial deformity, the knee joint function was satisfactory in the subsequent development. After a long interval without symptoms the patient developed a medially accentuated osteoarthritis of the knee.     

Intra-articular correction of extra-articular tibial deformities with total knee arthroplasty

INTRODUCTIONExtra-articular leg deformities may occur in the femur or tibia from mal-unions from previous trauma or metabolic bone disease. Secondary osteoarthritis at the knee occurs due to loss of mechanical alignment of the limb. At surgery for total knee arthroplasty, mechanical alignment can be restored intra-articularly with appropriate bone cuts and soft tissue balancing.PRESENTATION OF CASEWe describe 2 case studies with extra-articular tibial deformities (9° and 24° varus deformity) which were corrected with a 1 stage procedure of total knee arthroplasty with intra-articular deformity correction.DISCUSSIONPatient selection, pre-operative considerations and surgical technique are discussed with reference to the literature.CONCLUSIONOne stage intra-articular correction of extra-articular deformity is suitable for mild degrees of varus deformities (<30°). Staged corrective procedures with larger deformities in the tibia or femur can be performed with extra-articular osteotomies on top of intra-articular corrections. Consideration should be given to the use of computer navigation when conventional jigs cannot be applied to deformed bone.     

Comprehensive treatment of late-onset tibia vara

BACKGROUND: Late-onset tibia vara (Blount disease) can be difficult to treat because of frequent morbid obesity and associated deformities, including distal femoral varus, proximal tibial procurvatum, and distal tibial valgus, that contribute to lower extremity malalignment. We present a comprehensive approach that addresses all components of the deformity and allows restoration of the anatomic and mechanical axes. METHODS: Fifteen consecutive patients (nineteen lower extremities) with late-onset tibia vara were managed with this comprehensive approach. The mean age of the patients at the time of surgery was 14.9 years, and the mean weight was 113 kg. Standing anteroposterior and lateral radiographs were made preoperatively and at the time of the final follow-up. Preoperatively, the mean mechanical axis deviation was 108 mm, the mean lateral distal femoral angle was 95 degrees , and the mean mechanical medial proximal tibial angle was 71 degrees . In all nineteen extremities, the proximal tibial varus deformity was corrected by means of a valgus osteotomy and application of an Ilizarov ring external fixator. Distal femoral varus was corrected by means of either hemiepiphyseal stapling or valgus osteotomy with blade-plate fixation in thirteen of the nineteen extremities. Distal tibial valgus was treated either with hemiepiphyseal stapling or with varus osteotomy and gradual correction with use of the Ilizarov external fixator in eleven of the nineteen extremities. RESULTS: After a mean duration of follow-up of 5.0 years, the mean mechanical axis deviation had improved to 1 mm (range, 20 to -30 mm), the lateral distal femoral angle had improved to 87 degrees (range, 83 degrees to 98 degrees), and the mechanical medial proximal tibial angle had improved to 88 degrees (range, 83 degrees to 98 degrees ). The mean time required for correction of the proximal tibial varus deformity was thirty-one days, and the external fixator was removed at a mean of 4.5 months postoperatively. All patients had development of one or more superficial pin-track infections (mean, 1.9 pin-site infections per patient). No wound infections, nonunions, or neurovascular complications occurred. Eighteen of the nineteen extremities were pain-free at the time of the final follow-up. CONCLUSIONS: This comprehensive approach allowed restoration of the mechanical and anatomic axes of the lower extremity in patients with late-onset tibia vara, resulting in a resolution of symptoms as a result of normalization of the weight-bearing forces across the knee and ankle. We believe that this approach will decrease the risk of early degenerative arthritis of the knee.     

Infantile tibia vara: Treatment of Langenskiold stage IV

An eight year old girl presented with a progressively increasing deformity of the left proximal tibia since last 2 years. She had no history of trauma, fever and swelling of left knee. There were no obvious signs of rickets/muscular dystrophy. She had 25 degrees of tibia vara clinically with lateral thrust and a prominent fibular head. The radiograph of left knee revealed tibia vara with medial beaking and a significant depression of the medial tibial epiphysis and metaphysis. A computed tomography (CT) scan revealed significant depression of the medial tibial epiphysis but no bony bar in the physis or fusion of the medical tibial epiphysis. There was a posterior slope in addition to the medial one. She was treated with elevation of the medial tibial hemiplateau with subtuberosity valgus derotation dome osteotomy. She also underwent a lateral proximal tibial hemiphysiodesis (temporary stapling). A prophylactic subcutaneons anterolateral compartment fasciotomy was also performed. All osteotomies united in 2 months. All deformities were corrected and she regained a knee range of 0 to 130 degrees. At final followup (4 years), there was no recurrence of varus deformity, knee was stable, with 1cm of leg length discrepancy. In Langenskiold stage IV tibia vara, elevation of medial tibial plateau, a subtuberosity valgus derotation osteotomy and a concomitant lateral hemiephiphysiodesis has given good results.     

Varus Collapse in Total Knee Arthroplasty: Does Fixation or Bone Fail First?

IntroductionAseptic tibial loosening is now considered the most common reason that total knee arthroplasties (TKA) fail long term. There are unique subsets of patients that fail into varus alignment of the tibial tray with collapse of the medial proximal tibia. It is currently unknown if the implant fixation fails first or if the proximal medial tibia collapses first.MaterialsWe performed a retrospective analysis of 88 patients that were revised at our institution secondary to aseptic varus collapse of the proximal tibia. Two fellowship-trained arthroplasty surgeons performed a retrospective analysis on sequential precollapse radiographs in each patient to determine which failed first: the implant fixation (implant-cement or cement-bone interface) or the medial proximal tibia.Discussion36/88 (40.9%) patients had a series of precollapse radiographs that could be reviewed. Failure at the implant-cement interface before varus collapse in 23 vs 22 patients, failure at the implant-cement and cement-bone interface before varus collapse in two patients, and contemporaneous failure at the implant-cement interface and varus collapse in 11 vs 12 patients were identified by reviewers one and two, respectively.ConclusionThe most frequent mechanism of failure identified was failure of the implant-cement interface followed by subsequent medial tibial varus collapse. Improving implant fixation may decrease the incidence of this unique failure mechanism. We advocate the use of supplemental stem fixation in high-risk patients and optimal cement techniques for all patients as methods of potentially avoiding tibial varus collapse, one of the most frequent modes of long-term failure.     

Fixator-assisted Technique Enables Less Invasive Plate Osteosynthesis in Medial Opening-wedge High Tibial Osteotomy: A Novel Technique

BackgroundOpening-wedge high tibial osteotomy is a well-established procedure in the management of medial osteoarthritis of the knee and correction of proximal tibia vara. Recently, surgical approaches using less invasive plate osteosynthesis have been used with the goal of minimizing complications from more extensive soft tissue exposures. However, to our knowledge, less invasive fixator-assisted plate osteosynthesis has not been tested in the setting of opening-wedge high tibial osteotomy.Questions/purposesThe purposes of this study were (1) to assess the complications associated with use of a fixator-assisted less invasive plate osteosynthesis technique to stabilize an opening-wedge high tibial osteotomy in the treatment of proximal tibial vara; and (2) to evaluate the ability of this technique to achieve correction of the proximal tibial deformity and achieve osseous union.MethodsFrom June 2011 to June 2013, a total of 157 limbs in 83 patients who underwent fixator-assisted high tibial osteotomy for (1) idiopathic genu vara; or (2) osteoarthritis of the knee with proximal tibia vara were initially enrolled. Of these, eight limbs (5%) were excluded on the way; thus, 149 limbs in 77 patients were evaluated. During the period in question, no other techniques were used for proximal tibial osteotomy. The surgical procedures included less preparation of soft tissue, proximal tibial osteotomy, application of a temporary external fixator, correction of alignment, and final fixation with the help of an external fixator. Complications were assessed by chart review and the alignment in both coronal and sagittal planes was compared pre- and postoperatively. Radiographic review to confirm osseous union and alignment was performed by two of the authors not involved in clinical care of the patient. Delayed union was described as union occurring later than 4 months.ResultsThirty limbs out of 149 tibiae (20%) showed complications, all of which were resolved without leaving any sequela. Twenty-seven limbs out of 149 limbs (18%) showed lateral cortical hinge fracture and three limbs out of 149 limbs (2%) showed soft tissue complications (two superficial infections, one wound hematoma). The overall completeness of reaching the target correction was excellent. In the coronal plane, the difference between the amount of real correction and the amount of target correction was 0.3° ± 0.7° (p < 0.001). In the sagittal plane, the difference between pre- and postoperative posterior proximal tibial angle was −0.1° ± 0.2° (p < 0.001). All osteotomies healed before 4 months.ConclusionsFixator-assisted high tibial osteotomy is a valid option for medial opening-wedge high tibial osteotomy, which enables less invasive surgery with excellent coronal/sagittal/rotational alignment control. However, future studies should compare this approach with other approaches for proximal tibial osteotomy to ascertain whether indeed this procedure is less invasive or more reliable.

Level of Evidence

Level IV, therapeutic study.     

Impact of Tibial Component Coronal Alignment on Knee Joint Biomechanics Following Fixed‐bearing Unicompartmental Knee Arthroplasty: A Finite Element Analysis

ObjectiveUnicompartmental knee arthroplasty (UKA) has indicated a higher rate of revision than total knee arthroplasty (TKA). The success of UKA depends on UKA component alignment, fixation, and soft tissue integrity. The purpose of this study was to investigate the effects of different tibial component alignments in the coronal plane on the stress distribution in UKA. It was hypothesized that the stress distribution would approach native knee when the tibial component was neutrally positioned.MethodsThe left legs from two healthy volunteers were considered to represent the geometric native knee models. All bones within the knee joint were extracted from the three‐dimensional (3D) computed tomography (CT). MRI was used to generate cartilage, menisci, and four major ligaments. The UKA components were virtually implanted in the medial compartment of the knee model using MIMICS. A total of five different configurations of UKA tibial obliquity in the coronal plane (neutral, 3° varus, 6° varus, 3° valgus, and 6° valgus) were adopted and investigated. Subject‐specific inhomogeneous material properties of bones were used in the finite element analysis (FEA) model. The von Mises stress in the tibia platform and proximal tibia, and the load distribution between the medial and lateral compartments were extracted and compared among the five different configurations.ResultsThe inhomogeneous material properties of the trabecular bone were closer to real physics than traditional homogeneous methods. Neutral and 3° varus alignments of the tibial component in the coronal plane have better stress distribution between medial and lateral compartment as healthy knee models, and less stress‐shielding effects than other UKA configurations. The stress pathway under the medial tibia platform in neutral and 3° varus UKA configurations was similar and more obvious than the other three UKA configurations. Notably, the stress of the medial tibia platform in the 3° varus UKA models was more homogenous than the neutral UKA configuration. The 6° varus, 3° valgus, and 6° valgus UKA models had higher stress at the location of anterolateral and posterolateral tibia platform than other UKA configurations.ConclusionNeutral or 3° varus positioned in the coronal plane for the tibial component could be the optimal alignment for UKA. Excessive varus or valgus obliquity in the coronal plane lead to significant differences in bone stress transfer and load distribution in the knee, and increase the risk of UKA failure.     

Rotational profile of lower limb and axis for tibial component alignment in varus osteoarthritic knees

The purposes of this study were to describe the changes in tibial torsion and knee rotation in varus osteoarthritic knees and to check the reliability of reference axis, for tibial component placement, based on femoral transepicondylar axis in these patients. A secondary goal was to determine which reference axis based on proximal tibia is most accurate for determining tibial component rotation. Fifty-two varus osteoarthritic knees and 20 normal knees were analyzed using computed tomographic scan. Tibial torsion and knee rotation were significantly reduced in patients with osteoarthritis. Reference axis based on posterior tibial condyles was most accurate and least variable for tibial component alignment. A significant negative correlation was found between knee rotation and tibial axis based on transepicondylar axis (r = -0.485).     

Impact of Proximal Tibial Varus Anatomy on Survivorship After Medial Unicondylar Knee Arthroplasty

BackgroundPrecise indications for medial unicondylar knee arthroplasty (UKA) continue to be defined. It is unclear if patients who have proximal tibia vara should be considered candidates for UKA. The purpose of this study was to evaluate the impact of proximal tibial varus alignment on outcomes after UKA.MethodsA retrospective review identified 2,416 patients (3,029 knees) who underwent mobile-bearing medial UKA with 2-year minimum follow-up or revision. Preoperative radiographs were evaluated, and medial proximal tibial angle (mPTA) was measured. Patients were grouped into two groups as follows: mPTA <80 degrees and mPTA ≥80 degrees. Analyses were performed on the impact of mPTA on clinical outcomes, all-cause revisions, and tibial failures.ResultsAt a mean follow-up of 5 years (range, 0.5 years to 12.8 years), there was not a statistically significant difference in clinical outcomes nor increased risk for all-cause revision or tibial failure in patients who had an mPTA <80°. Mean mPTA in patients who had tibial failures was 82.5° and not significantly different than those who did not have a tibial failure (82.9°) (P = .289). Tibial failure rate in knees with an mPTA <80° was 2.2% and not significantly different than knees with an mPTA ≥80° at 1.4% (P = .211). The all-cause revision rate in knees with an mPTA <80° was 5.8% and was not significantly different than knees with an mPTA ≥80° at 4.9% (P = .492).ConclusionPatients who have tibia vara are not at increased risk for tibial related or all-cause failure in medial UKA. This data may allow surgeons to increase their indications for medial UKA.     

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.     

A comparative study of weight-bearing and non-weight-bearing 3-dimensional lower extremity alignment in knee osteoarthritis

BackgroundLower extremity alignment is an important variable with respect to the development and progression of knee osteoarthritis. It is very essential for the preoperative planning of realignment surgeries such as total knee arthroplasty and high tibial osteotomy. Nevertheless, there have been no reports comparing 3D lower extremity alignment between weight-bearing upright and non-weight-bearing horizontal states in osteoarthritic knees in the same subject. Therefore, we determined whether the alignment of the lower extremity in the weight-bearing upright state differed from that in the non-weight-bearing horizontal or supine position in patients with knee osteoarthritis.MethodsAdduction–abduction, flexion–extension, and rotational angle of osteoarthritic knees were assessed in weight-bearing upright and non-weight-bearing supine positions. Knee alignment in the supine position was determined from preoperative computed tomography data. In the weight-bearing upright state, alignment was determined using a technique that utilized 2D-3D image-matching with biplanar computed radiography and 3D bone models of the complete lower extremity rebuilt using computed tomography-based information.ResultsWe assessed 81 limbs from osteoarthritic knee patients (74 women, 7 men; mean age 75.3 years, range 59–86 years). In the coronal plane, there were varus deformities in both the supine and standing positions, while there was flexion in both the supine upright state and position at the sagittal plane. In the axial plane, the rotation of the tibia to the femur was neutral in the supine position and internal in the upright state.ConclusionPatient position significantly affects lower extremity alignment in osteoarthritic knees. This study provides important data regarding the preoperative evaluation of realignment surgery in total knee arthroplasty and high tibial osteotomy. We believe that these results are an important contribution to the knowledge regarding knee osteoarthritis.     

Factors Correlated with the Reducibility of Varus Deformity in Knee Osteoarthritis: An Analysis Using Navigation Guided TKA

Background

We hypothesized that a number of clinical and radiologic parameters could influence the reducibility of varus deformity in total knee arthroplasty. The aim of this study was to identify the factors correlated with reducibility of varus deformity and predict more accurately the amount of medial soft tissue release required in varus deformity total knee arthroplasty.

Methods

One hundred forty-three knees with preoperative varus alignment and medial osteoarthritis were included in this retrospective study. The total knee arthroplasties were performed using a navigation system (OrthoPilot) by single surgeon. To assess varus deformity, the authors measured preoperative mechanical axis angles and valgus stress angles. Mechanical tibial angles, mechanical femoral angles, femoral osteophyte sizes, and tibial osteophyte sizes were measured. The Ahlbäck grading scale was applied for radiologic parameters, and clinical parameters (age, body mass index, sex, duration of pain, and preoperative range of motion) were documented. Correlations between these factors and preoperative valgus stress angle were analyzed.

Results

A negative correlation was found between preoperative mechanical axis angle and preoperative valgus stress angle (p < 0.01, r = -0.38), and a positive correlation was found between the preoperative mechanical tibial angle and preoperative valgus stress angle (p = 0.01, r = 0.19).

Conclusions

The present study shows that preoperative varus deformity and proximal tibial vara (measured by preoperative mechanical axis angle and mechanical tibial angle, respectively) are correlated with reducibility of varus deformity (measured by preoperative valgus stress angle), and clinical parameters (age, range of motion, duration of pain and body mass index) and other radiologic parameters (osteophyte size, severity of osteoarthritis and angulation of distal femoral joint surface) were not significantly correlated with reducibility of varus deformity.     

Stress fracture of proximal tibia after proximal fibula osteotomy: A case report

IntroductionProximal fibula osteotomy (PFO) is a new method for treating medial compartment osteoarthritis of the knee, which is based on the theory of differential settlement (nonuniform settlement). This procedure has been widely recognized for its advantages of relative simplicity, low rate of postoperative complications, and low postoperative costs. Stress fracture of the proximal tibia after PFO has not been previously reported.Case presentationWe report a 62-year-old woman with chronic rheumatoid arthritis (RA) underwent left PFO for chronic knee pain, who developed a stress fracture of the proximal tibia more than 1 year after PFO.Clinical discussionIn the early stage of proximal tibia stress fracture, due to the concealment of radiography manifestations, doctors from another hospital performed total knee arthroplasty (TKA) for the patient. They ignored the treatment of stress fracture of the proximal tibia, and the stress fracture was further aggravated after surgery. Six months later, the patient underwent open reduction and internal fixation with a plate and screw in the left proximal tibia fracture at our hospital. The patient was followed up at the hospital three months after open reduction, and the proximal tibia stress fracture began to heal.ConclusionRA is usually not confined to the medial compartment and its pathogenesis is different from that of osteoarthritis. Therefore, PFO is not an appropriate procedure for this type of patient.     

Effects of Total Hip Arthroplasty on Axial Alignment of the Lower Limb in Patients with Unilateral Developmental Hip Dysplasia (Crowe type IV)

BackgroundThe aim of this study was to evaluate the influence of total hip arthroplasty on axial alignment of the lower limb in adults with unilateral developmental hip dysplasia (Crowe type IV).MethodsWe retrospectively reviewed medical records of 50 adults who underwent total hip arthroplasty, in which the acetabular cup was placed in the anatomical position. The following parameters were measured before surgery, immediately after surgery, and two years later: mechanical axis deviation (MAD), tibiofemoral angle (TFA), femoral offset, hip-knee-ankle angle (HKA), mechanical lateral distal femoral angle (LDFA), mechanical medial proximal tibial angle, height of medial femoral condyle, height of lateral femoral condyle, and leg lengthening. Length of the resected femoral segment was also recorded from medical records.ResultsPreoperative MAD, TFA, HKA, and LDFA of the ipsilateral lower limb showed significant valgus deformity. MAD of the ipsilateral lower limb and valgus inclination were significantly smaller immediately after surgery than before, while TFA, HKA, femoral offset, and LDFA were significantly larger (P < 0.05). These parameters did not differ significantly between immediately after surgery and two years later (P > 0.05). Ipsilateral extremities were extended by a mean of 2.54 cm (range, 0 to 5.35 cm). The mean length of the femoral resected segment was 3.56 cm (range, 2.03 to 5.74 cm). The contralateral lower limb showed marginally smaller MAD and medial proximal tibial angle after surgery than before, but larger LDFA, TAF, and HKA.ConclusionsIn patients with developmental hip dysplasia who underwent total hip arthroplasty with placement of the acetabular component at the level of the anatomic hip center, axial alignment of the ipsilateral lower limb was immediately altered, and valgus inclination was significantly reduced. The procedure only slightly altered the axial alignment of the contralateral lower limb.     

Arthroplasty in treating knee osteoarthritis and proximal tibia stress fracture

The authors describe two cases of severely angulated tibial non-unions after proximal tibia stress fractures associated with ipsilateral osteoarthritis treated with modular knee endoprosthesis with a long tibial stem to stabilize non-union fragments. During the procedure, no additional osteosynthesis or bone grafting was added. Both non-unions healed after 6 months with no post-operative complications. The authors suggest implantation of modular knee endoprosthesis, as a single procedure, in treatment of proximal tibia non-union after a stress fracture as a result of severe varus/valgus deformity. It provides a solution for osteoarthritis treatment, axis correction and non-union osteosynthesis.     

Stress fracture of the distal tibia secondary to severe knee osteoarthritis: a case report

Stress fracture of the tibia secondary to sports-related activities is relatively common, but rarely occurs secondary to osteoarthritis of the knee. Such fractures usually involve the proximal tibia. We report a 61-year-old woman with osteoarthritis and severe varus deformity of the knee who had a stress fracture of the distal tibial shaft. The patient had declined total knee replacement for severe osteoarthritis. She developed a stress fracture that subsequently malunited. The patient presented late and the diagnosis was not made for several months. The pathomechanics, diagnosis, and management options for this patient are discussed.