THE FEATURES OF HIP ARTHROPLASTY IN POSTTRAUMATIC LESIONS OF THE PROXIMAL FEMUR
Bashkir State Medical University,
Ufa State Aviation Technical University,
Ufa, Russia
Numerous sociologists indicate one of the main problems of the modern society – human’s ability to lead independent life. This social characteristic is especially important for persons with hip joint pathology, where the notion “independent life” means a physical component of life quality, which is based on independent moving. At the present time, independent freedom is determined by condition of the supporting-motor system and its relevant segments including pelvic girdle. However surgical correction of hip joint defects provides the earliest adaptation of patients [1, 2, 3]. Efficiency of treatment with arthroplasty techniques is predetermined by interaction between the body and the implant. The most important component of such interaction is the feature of osteointegration at the border between a bone and the implant. On the one hand, the harmony in interactions for this transition reflects the state of kinematic balance, and, on other hand, it leads to some systemic disorders and defects in this interaction [4, 5].
According to the opinion by some specialists, recurrent surgical interventions are required for 2.44-10.99 % of all complications of osteosynthesis for the proximal hip. The studies of arthroplasty outcomes after proximal hip osteosynthesis showed high rates of complications (27.78-38.1 %) and high rate of revision arthroplasty (12.34-15.91 %), which increases after osteosynthesis of transtrochanteric and subtrochanteric fractures [6, 7, 8].
The necessity of hip arthroplasty appears as result of decompensated structural functional dysfunctions after reduction and reconstructive interventions for the proximal hip: avascular necrosis of the femoral head, decompensated posttraumatic osteoarthrosis, false joint, failure of osteosynthesis, infectious complications, chronical pain syndrome in the hip joint. Treatment with arthroplasty techniques for such patients is associated with some advantages in view of early activation and adaptation. However estimation of phase state of connective tissue and realization of hip joint endoprosthetics have some features and difficulties in patients after reduction and reconstructive interventions for the proximal hip. It requires research of the problem. Therefore, diagnostics and treatment for this group of patients are attractive for the orthopedists who deal with hip arthroplasty, as well as for rehabilitation experts.
Objective – to compare the treatment outcomes of hip arthroplasty after reduction-reconstruction interventions for the proximal hip.
MATERIALS AND METHODS
The study presents the results of the examination of 81 patients after reduction and reconstructive interventions for the proximal hip who received hip arthroplasty. The mean age of the patients was 56.59. There were 59.26 % of the men (48 persons). The patients of the main group were distributed into two subgroups: the patients of the first subgroup (42 patients, mean age of 56.67) received presurgical planning with X-ray image and traditional rehabilitation; the second subgroup (39 patients, mean age of 54.64) received presurgical projecting on the basis of TraumaCad 2.4, and with use of 3D modeling and estimation of load distribution in Ansys 15.0 software, and the original rehabilitation with the medical measures Nadezhda. The period of postsurgical observation was up to 9 years. The control group included 43 patients (mean age of 56.23) with idiopathic osteoarthrosis of the hip joint. They received primary arthroplasty (table 1). Postsurgical observation was up to 10 years. The study did not include the patients with decompensated pathology of the spine, pathology in other segments of the lower extremities and with concurrent severe diseases.
| Table 1 | ||||||
| The clinical patterns of the patients in the main and control groups | ||||||
| Note: * - standard deviation |
The research techniques:
- Estimation of orthopedic status of the patient;
- Structural changes in segments of pelvic girdle estimated with radial monitoring (radiography, computer tomography, magnetic resonance imaging, osteodensitometry, osteoscintigraphy, thermography);
- Estimation of kinematic status on the basis of biometrics of supporting and walking phases (stabilometry, goniometry, podography), electromyography with Trast-M (the measures for diagnostics, treatment and rehabilitation of motion pathology), the stabilometric platform ST-150 (Biomera), roentgenocinematography;
- Estimation of motional activity with Walking style One 2.1 HJ-321-E (Omron);
- Estimation of functional state with Harris scale;
- VAS for estimation of pain;
- QOL-100 for estimation of life quality.
Mann-Whitney non-parametric test was used for statistical analysis of results of treatment and estimation of reliability of differences (p < 0.05 was statistically significant). The study was conducted with concordance to the ethical standards of Helsinki declare. All persons were informed, and they gave their consent for participation. The study protocol was approved by the ethical committee of Bashkir State Medical University (the protocol #11, December, 23, 2014).
RESULTS
In the main group the reduction-reconstruction interventions for the proximal hip were mainly conducted for fractures of the femoral neck (43 cases, 53.09 %), with fixation with cannulated screws as the main surgical technique (table 2).
| Table 2 | ||||||
| Previous reduction-reconstructive interventions for the proximal femur | ||||||
According to the observation, the complications after reduction-reconstruction interventions were avascular necrosis of the femoral head, formation of a false joint, decompensated osteoarthrosis of the hip joint, deep infection (table 3).
| Table 3 | |||||||
| The causes of decompensated hip lesions after reduction-reconstructive interventions | |||||||
Estimation of orthopedic status identified extremity deformation (shortening, excessive external rotation), hip joint contracture, muscular atrophy, chronic pain syndrome. Long term absence of supporting ability of the lower extremity resulted in kinematic and psychologic disadaptation resulting in persistent pathologic motion patterns, which were resistant to restoration.
We found some specific patterns of changes in the proximal hip which prevented realization of arthroplasty of hip joint in dependence on the method of reduction-reconstruction interventions (table 4). The greatest amount of the cases was associated with some complications: varus complications, extension and rotation displacement of the proximal hip; the combination of sclerotic foci and bone tissue defects in view of incomplete remodulation of bone tissue; incorrect anatomic position of lesser and greater trochanter; decreasing density of bone tissue in the intact part of the hip; changes in radiologic-anatomic relationships in the hip joint, i.e. disorders of evenness, embowed shape and continuality of Shenton's arch and Calve's line; secondary changes in the acetabulum.
| Table 4 | |||||||
| The features of posttraumatic femoral changes in dependance on osteosynthesis type | |||||||
All cases demonstrated weakening in various regions of the proximal hip. It favored significant increasing amount of inevitable additional injuries. Intrasurgical fractures with necessity of additional fixation after arthroplasty were noted in 13 patients (30.95 %). For prevention of this complication we used cerclage technique for the second subgroup before preparation of the intramedullary canal. Cerclage was used below the lesser trochanter. It significantly decreased the rate of fractures during preparation of the hip (7 cases, 17.95 %, p < 0.05). Also we found the increasing rate of administration of bone plastics in presence of defects in the proximal hip and in the acetabulum: 12 cases in the subgroup 1 (28.57 %), 11 cases in the subgroup 2 (28.21 %). There were no intrasurgical fractures in the control group. 4 patients (4.94 %) received bone plastics for insignificant defects of the acetabulum. It was less than in the subgroups 1 and 2 (p < 0.05). Changes in the femoral diaphysis and in soft tissues were found after use of dynamic femoral screws and cephalomedullary constructs.
Presurgical planning of hip arthroplasty acquires special significance in view of significant changes in anatomy of the proximal hip and the acetabulum. Administration of conventional planning methods with X-ray image does not allow adequate determining the positioning points for the endoprosthesis. Therefore, use of TraumaCad in combination with 3D modelling for presurgical planning with subsequent estimation of load distribution in Ansys 15.0 allows selecting the sizes of the implant and calculating the square of supporting surface and distribution of direction and magnitude of force for the target point of movement of kinematic knot in patients after reduction-reconstruction interventions for the proximal hip. The presurgical model of the affected joint was developed on the basis of fast prototyping with non-invasive precise stereolithography with use of digital parameters after computer tomography (Fig. 1).
Figure 1
a – the presurgical project based on TraumaCad; b – the volumetric pelvic model; c – 3d model of the injured segment; d – the X-ray image of hip joints one year after arthroplasty; e – osteodensimetry one year after arthroplasty; f – bone scanning one year after arthroplasty.
a 
b 
c
d 
e
f
Then the following parameters were estimated: turning point, calculation of square of bearing surface, distribution of load for the target point of movement of kinematic knot, selection of optimal location of components of the endoprosthesis and the autograft, harmonious orientation of direction and magnitude of force in periimplant region. Cinematography allowed estimating the true volume of motions in the joints, rotation centre of the hip joint and the features of kinematics of an affected segment in three planes.
The clinical case: a woman, age of 20. The diagnosis: “Dysplastic osteoarthrosis of degree 3, state after opened reduction of femoral dislocations, bilateral reconstruction of the proximal hip; mixed contracture of the hip joints; 4.5 cm shortening of the left lower extremity”. Presurgical level of pain was 7 points according to VAS, 2.2 points, and 42 points according to Harris scale; the postsurgical level was 88 points (Fig. 1).
Functional perisurgical rehabilitation was initiated at presurgical stage in the subgroup 2. It included remedial gymnastics on the basis of Nadezhda medical complex, muscular electric stimulation of the lower extremities, restoration and training of vertical stability with use of the stabilometric platform, pharmaceutical correction of bone metabolic disorders. During the process of rehabilitation we made individual calculations of supporting load to the operated extremity with consideration of age, sex, body mass, results of radiography, computer tomography, features of nosology and characteristics of placement of the endoprosthesis (the degree of coverage of the cup, use of bone plastics, cement or cementless fixation).
Objective monitoring was conducted on the basis of osteodensitometry, stabilometry, goniometry, podography, electromyography, a pedometer, estimation of functional state with Harris scale and quality of life with QOL-100.
Osteodensitometry found decreasing bone mineral density (BMD) in all segments in both groups. The most intense decrease was in the lower extremities within 2 years after hip arthroplasty (Fig. 2, 3). The degree of decreasing BMD was more statistically significant in the main group (p < 0.05).
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Figure 2 Changes in pelvic and low extremities BMD within 3 years after arthroplasty in the main group |
Figure 3 Changes in pelvic and low extremities BMD within 3 years after arthroplasty in the control group
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Biometry of supporting and walking phases for the patients at basic condition found instability in the frontal and sagittal planes, increase in the square of a statokinesiogram and decreasing efficiency of energetic balance. The most informative biochemical parameters were speed of walking, changes of the curves of supporting responses, changes of degrees of flexion and extension angles in the hip and knee joints, rhythmicity or walking asymmetry. One year after arthroplasty the pathologic changes of these values were in 85.71 % of the patients in the main group and in 72.09 % in the control group (p < 0.05).
The other features of arthroplasty after reduction-reconstruction interventions for the proximal hip were increasing blood loss and, as result, increasing amount of transfusions of packed red cells (452.33 ± 63.94 ml), increasing duration of surgery (119.05 ± 12.41 min). The control group demonstrated lower average duration of arthroplasty (81.43 ± 12.38 min, p < 0.05), and the volume of transfusion of packed red cells was 181.55 ± 68.98 ml (p < 0.05). One of the causes of increasing duration of surgery was difficulties with removal of the implants. It required bone trepanation for removal of a metal constructs in 17 cases.
Estimation of functional possibilities with Harris scale, of motional activity with use of pedometers, of pain with VAS and quality of life with QOL-100 showed the similar and better results in the control group and in the second subgroup than in the first subgroup (table 5).
| Table 5 | ||||
| The results of treatment 3 years after arthroplasty | ||||
DISCUSSION
Surgical treatment of hip joint disorders by means of arthroplasty technique as the most efficient way of early functional rehabilitation is associated with the range of the problems because of the features of the structure of the proximal hip after reduction-reconstruction interventions. Each reduction-reconstruction technique and the features of fixing systems result in the specific changes in bone and soft tissue structures of the proximal hip and the acetabulum in view of sclerosis of spinal canal and bone tissue around metal construct, development of defects of bone tissue as result of significant extraction of the bone in the region of the implant.
We found some specific patterns of changes in the proximal hip which complicated realization of hip arthroplasty in dependence on the technique of fixation. After fixation with dynamic femoral screw and cephalomedullary systems we observed destruction of the lateral cortical layer, bone sclerosis around the screws in the femoral neck, around the nail in the spinal canal, significant extraction of the bone in the region of screw placement and bone defects in the region of the great trochanter in the site of nail penetration. Use of cannulated screws resulted in the changes in view of weakening of the subtrochanteric region, bone tissue destruction as result of limitation of load to the lower extremity that favored significant decrease in bone tissue density, muscular atrophy, increasing risk of periprosthetic fractures during hip joint arthroplasty.
Selection of a method of arthroplasty was based on the algorithm of estimation of reduction, reparation and substitution of the proximal hip. It was found that primary callus developed in anatomic reposition, secondary callus with impaction of surrounding tissues prevailed in absence of anatomic reduction; henceforth, it impeded adequate positioning of the endoprosthesis. The important aspect for choice of optimal time of arthroplasty was intensity of reparation and substitution of callus until bone tissues restored. Monitoring of these processes should be realized with use of the radial diagnostic techniques (radiography, computer tomography, magnetic resonance imaging, bone scanning, osteodensitometry). Choice of optimal terms and techniques of arthroplasty should be based on the basis of the algorithm of estimation of reduction of the proximal hip, intensity of reparation processes and substitution of callus with consideration of phase condition of connective tissue.
Surgical treatment of hip disorders with use of arthroplasty after reduction-reconstruction interventions is associated with some differences and specific complications conditioned by the features of distribution of load to the adjoining segments. Therefore, it requires careful presurgical planning, which should be realized with consideration of the square of supporting surface and with distribution of load of the target point of kinematic knot. Presurgical planning of hip arthroplasty on the basis of 3D reconstruction with use of the modern software (in contrast to standard planning with use of X-ray images) optimizes selection of the implant with consideration of anatomy of the segment and type of the endoprosthesis that is especially important for patients after reduction-reconstruction interventions for the proximal hip and the acetabulum. In combination with complex perisurgical rehabilitation it allowed optimizing restoration of patterns of locomotor responses and improving functional state and quality of life of patients.
CONCLUSION
Hip arthroplasty for decompensated disorders of the hip joint relates to the number of the most efficient techniques of surgical treatment improving quality of patients’ life. However the range of the useful properties of such surgical technique significantly decreases in persons after reduction-reconstruction interventions. As result, it requires a special approach to treatment of this category of patients with use of estimation of phasic state of connective tissue with consideration of reduction, reparation and substitution of the proximal hip.
The analysis of the short term and long term results in the standard approach to treating patients after reduction-reconstruction interventions with arthroplasty technique identified increasing risk of unsatisfactory outcomes, mistakes and complications that is associated with absence of consideration of phasic state of connective tissue, patterns of osteointegration in dependence on distribution of direction and magnitude of forces, the anatomic features of the proximal hip, mismatch between terms of volume of surgery, and inadequate functional rehabilitation.
The comparative analysis of the patients with hip pathologies found the different patterns of connective tissue in various groups of the patients. Sclerotic processes in bone tissue, capsule hypertrophy and muscular fibrosis prevailed in the patients with osteoarthrosis. The combination of intense hypotrophic, inflammatory and sclerotic processes was observed in the group of the patients after reduction-reconstruction interventions for the proximal hip and the acetabulum.
Presurgical planning of hip arthroplasty with use of Trauma Cad, 3D modelling and estimation of distribution of direction and magnitude of forces on the basis of precise stereolithography and Ansys software allows optimizing choice of the implant with consideration of segmental anatomy and a type of the endoprosthesis that is especially important for patients after reduction-reconstruction interventions for the proximal hip.
Estimation of kinematic status should be conducted on the basics of the integrative analysis of the data of goniometry, stabilometry, podography, radiocinematography, electromyography with the standard mode and after provocative tests, which reliably reflect the degree of compensation of pathology in the hip joint and the changes of kinematic balance before and after arthroplasty.
The study showed that hip arthroplasty with use of 3D modelling on the basis of stereolithography with consideration of phasic state of connective tissue, as well as with use of the algorithm for estimation of reduction, reparation and substitution of callus with the following complex functional perisurgical rehabilitation allow improving short term and long term results of treatment in patients after reduction-reconstruction interventions for the proximal hip.