In recent decades, the share of high-tech medical care in traumatology and orthopedics dramatically increased, including endoprosthetic replacement of major joints in the lower limbs: hip and/or knee joint [1]. Total hip replacement (THR) is a standard surgical procedure used for treatment of severe disorders [2]. The main purpose of hip replacement is pain relief and functional lower limb restoration allowing the patient to return to active role and improve his/her quality of life. When performing total hip replacement (THR), the endoprosthesis acetabular component and stem should have appropriate component size and position, which is essential for achieving good functional outcome and longevity of the prosthesis. However, incorrect positioning or sizing of the endoprosthesis components increases the risk of intraoperative and postoperative complications, such as limb lengthening or shortening, intraoperative fractures, aseptic loosening, dislocation of the endoprosthesis head, etc. [3]. All these contribute to postoperative pain in the operated joint, instability and premature failure of the endoprosthesis components, thereby bringing dissatisfaction to the patient and reducing his/her quality of life [4]. Joint replacement of any type requires preoperative planning and intraoperative control. Preoperative planning is of utmost importance for optimization of the THR outcome. It helps the surgeon to visualize the final implant position after thorough assessment of clinical and radiography data [5]. In case of primary arthroplasty, preoperative planning can be performed using standard x-ray images, 2D templates or appropriate software. When performing primary arthroplasty in patients having a history of injury, osteotomy, surgical procedures, preoperative planning is hampered by non-compliance with the radioanatomical criteria.

Superimposition of the endoprosthesis templates onto the standard x-ray image of the hip joint for accurate sizing and positioning of the acetabular and femoral endoprosthesis components represents a conventional method of preoperative planning of THR.

Three-dimensional planning makes it possible to more clearly define the patient’s unique anatomical features and reference points and ensures optimal visualization for preoperative implant sizing. The 3D planning methods allow one to more accurately determine the size of the endoprosthesis acetabular component and stem (96–100%) compared to 2D templates (16–43%). The results confirm superiority of 3D methods over 2D templates in terms of implant sizing accuracy. The computed tomography data used in 3D planning represent an appealing alternative to navigation for restoration of the limb length and axis [6–9]. 

The lack of unified approaches to planning of surgical treatment prevents achieving identical treatment outcomes in similar clinical situations. It is necessary to create certain preoperative planning algorithm for selection of treatment tactics in patients with various joint disorders.

The study was aimed to compare the effectiveness of the three-step preoperative planning of hip arthroplasty based on the nosological form of degenerative and dystrophic disease of the hip joint and that of the standard method.

METHODS

Comparative analysis of outcome estimates for various methods of preoperative planning of THR was conducted. A total of 224 patients were enrolled. Inclusion criteria: grade III–IV (Kellgren & Lawrence classification) primary (idiopathic) osteoarthritis of the hip associated with grade III or more joint function impairment; grade II–III aseptic necrosis of the femoral head with severe pain; post-traumatic condition (condition after osteosynthesis for proximal femur or acetabulum fractures) with complications in the form of post-traumatic ostheoarthrosis or nonunion, and individuals in need of hip arthroplasty. The diagnosis was established based on the clinical and anamnestic data, as well as using instrumental assessment methods (radiography, computed tomography and magnetic resonance imaging). Exclusion criteria: infectious inflammatory disease of the affected segment; concomitant somatic disorders representing absolute contraindications to surgery; no informed consent submitted by the patient, age under 18 years. All patients were divided into two groups: index group (116 people) and comparison group (108 people). The index group was divided into three subgroups: 34 patients with ostheoarthrosis (average age 60.8 ± 7.2 years), 30 patients with avascular necrosis of the femoral head (average age 43.9 ± 7.9 years), 52 patients with post-traumatic hip joint disorders (patients of this group underwent osteosynthesis for fractures of the femoral neck, trochanter region of the femur, acetabulum of the pelvis, etc.) (60.2 ± 11.1 years). The comparison group was also divided into three subgroups:  33 patients with ostheoarthrosis (average age 61.3 ± 6.8 years), 29 patients with avascular necrosis of the femoral head (42.6 ± 8.4 years), 46 patients with post-traumatic hip joint disorders (59.3 ± 12.7 years). The average age of all surveyed patients was 57 ± 6.2 years, 119 people (53.12%) were females, 105 people (46.87%) were males.

In the index group (n = 116), preoperative planning of hip arthroplasty was performed in three phases.

In the first phase, bone density in the acetabular and femoral areas was determined in three planes based of the hip joint computed tomography (CT) data using the Hounsfield scale. Bone density was assessed around the perimeter of the zones of fixation considering the planned implant location and installation site. Determination of the zone with optimal bone density and the regions with reduced bone density, osteosclerosis, cysts and various defects was an important criterion of the endoprosthesis installation and positioning. When performing preoperative planning in patients having a history of osteosynthesis, it was difficult to determine bone density in the zones of fixation due to the presence of “metal artifacts” (fig. 1 and fig. 2).

In the second phase, the TraumaCad v. 2.4 software (Brainlab; USA) was used to determine the optimal size and position of the endoprosthesis components. For that x-ray image of the pelvis with the hip joint was uploaded to the program, over which the digital template of the endoprosthesis femoral and acetabular components was superimposed. However, when performing preoperative planning of endoprosthetic replacement using software, complete proximal femur visualization was hampered by the presence of surgical hardware (fig. 3).

In the third phase, the Geomagic Studioс (Raindrop Geomagio Inc.; USA) and 3D Slicer (Copyright 2023, Slicer Community; USA) software was used for virtual installation of the endoprosthesis components following construction of a volumetric model of the baseline condition (fig. 4). This phase enabled estimation of the segment anatomy distortion, more accurate adjustment of the endoprosthesis positioning, provision of starting biomechanics, and determination of the hip arthroplasty tactics. In cases of severe hip joint deformities, computer modeling was combined with 3D printing of the affected segment before and after hip arthroplasty (fig. 5).

In the control group (n = 108), preoperative planning was performed by standard methods: posterioanterior x-ray images of the pelvis with the hip joint were used, over which the templates of the endoprosthesis components (draft) were superimposed to determine the implant size.

Preoperative planning was followed by surgical treatment, THR, in both studied groups.

RESULTS

The results were assessed based on the match of the endoprosthesis component dimensions determined before and during surgery (intraoperatively). The index group patients with osteoarthritis and avascular necrosis of the femoral head showed higher implant sizing accuracy, however, it was comparable with that of the control group (p > 0.05). The subgroup with post-traumatic disorders showed significant differences in the accuracy of the intended endoprosthesis component size determination between the index and the control groups (р_c = 0.002). The main results and the implant sizing accuracy depending on the disease entity and the preoperative planning method are provided in tab. 1 and fig. 6.

DISCUSSION

Comparability of the results of the index and control group patients with osteoarthritis and aseptic necrosis could result from minor anatomy distortion in the segment of the pelvis and the lower limb, while in patients with post-traumatic disorders the planned endoprosthesis component dimensions in controls did not match actual size in more than a half of cases, which suggested low effectiveness of standard planning method in this group of patients due to more prominent segment anatomy distortion resulting from fractures, osteosynthesis or reconstructive surgery, as well as to the hip joint anatomy distortion, impaired joint congruence, secondary pelvic and spinal deformities, lower limb shortening by more than 3 cm [10–12].

The analysis resulted in creation of the algorithm for selection of preoperative planning method based on the forms of degenerative and dystrophic diseases of the hip joint and severity of the hip joint anatomy distortion (tab. 2).

CONCLUSIONS

The proposed approach to selection of preoperative planning technique makes it possible to accurately determine the endoprosthesis component dimensions and contributes to correct orientation and positioning of the endoprosthesis components during hip arthroplasty. The proposed algorithm of the three-step method showed higher effectiveness of preoperative planning and personalized design for patients with various nosological forms of degenerative and dystrophic diseases of the hip joint compared to the standard method, it also enabled accurate endoprosthesis component sizing. Preoperative planning of hip arthroplasty by the proposed method allows one to assess the disease characteristics at the local and systemic levels. The most challenging situations are observed in patients with post-traumatic disorders of the hip joint. This is due to the fact that patients of this group usually show severe bone disruption in the femoral and acetabular zones of fixation.