Fu Zhihou, Qu Xintao, Xu Ming, Liu Xiaochen
Department of Orthopedics, General Hospital of Jinan Military Region 250031
Osteolysis caused by wear particles, especially polyethylene submicron particles, is the main cause of hip prosthesis loosening and revision. Measures to reduce the source of particles include increasing the wear resistance of polyethylene, reducing oxidation, increasing cross-linking; or finding other prosthetic interfaces such as ceramic-polyethylene, ceramic-ceramic, metal-metal, etc. The literature reports ceramic-ceramic prostheses do not produce wear particles and have an extended prosthesis life. A total of 220 cases of 260 hips with aseptic necrosis of the femoral head were treated with ceramic-ceramic total hip arthroplasty from June 2000 to December 2010 in our hospital, which is reported as follows: Fu Zhihou, Department of Orthopedics, General Hospital of Jinan Military Region
1. Clinical data
1.1 General data: 158 male cases and 62 female cases. Age 36-57 years old, average 48 years old. All were patients with aseptic necrosis of femoral head stage III and IV. 32mm ceramic head 123 hips, 36mm large head ceramic 137 hips. Postoperative follow-up was 6 months-7 years, with a mean of 4 years and 2 months. The control group was a total of 367 cases of 377 hips with metal-polyethylene prosthesis performed at the same time, aged 31-70 years, with a mean of 57.7 years. The postoperative follow-up was 7 months-7 years, with a mean of 4 years and 4 months.
1.2 Methods
1.2.1 Functional evaluation: the Harris score was applied to assess the hip function.
1.2.2 X-ray evaluation: orthopantomogram of the hip joint was performed separately. Greun was applied to the acetabular side.
The acetabular side was divided and any translucent lines larger than 2 mm and any new translucent lines not seen before were recorded. On the femoral side, the Delee-Chanley division was used to record any displacement, subsidence, tilt, osteolysis or resorption of the prosthesis, any periprosthetic translucency lines larger than 2 mm, and any new translucency lines not previously seen.
1.2.3 Statistical analysis: SPPS software with t-test was applied for statistical analysis.
2. Results
The Harris score of patients in the ceramic-ceramic type prosthesis group was 78-94 with a mean of 90, and the Harris score of the metal-polyethylene prosthesis group was 76-93 with a mean of 88.5. No significant difference was seen between the two groups. While the extent or site of imaging loosening was significantly higher in the metal-polyethylene prosthesis group than in the ceramic-ceramic prosthesis group, regardless of acetabular side or femoral prosthesis side, no imaging failure of the prosthesis was seen in either group, and no prosthesis had to be revised (Figures 1, 2). Intraoperative complications were microfractures of the acetabulum in two cases. No postoperative dislocation or fracture of the prosthesis was observed.
3. Discussion
3.1 Superiority of ceramic-ceramic prosthesis-type total hip arthroplasty.
In 1970, Boutin first applied alumina ceramic prosthesis for hip arthroplasty, which produced the first generation of alumina ceramic prosthesis. In 1994, the third generation of ceramic prostheses was developed and the incidence of fracture was reduced to 0.01%. The ceramic prosthesis has good tissue compatibility and does not produce periprosthetic osteolysis and loosening caused by wear particles, with a reported short-term osteolysis rate of less than 1%, compared to 18% in the control metal-polyethylene group. In contrast, ceramic-polyethylene prostheses have poor medium- to long-term clinical outcomes due to the production of wear particles, with a 9-year revision rate of 38% [1, 2]
This study showed good clinical results in the near to mid-term of ceramic-ceramic total hip arthroplasty for aseptic necrosis of the femoral head, and although no significant differences were seen in Harris scores between the two groups, significant differences were seen in periprosthetic osteolysis and prosthetic loosening on imaging in the control group. Although clinical prosthesis loosening and imaging prosthesis loosening do not necessarily match exactly, several studies suggest that prosthesis displacement, periprosthetic translucency lines or osteolysis are still reliable indicators of prosthesis loosening [3]. Therefore, ceramic-ceramic type prostheses have fewer complications in the near to mid-term and correspondingly longer prosthesis life, making them more suitable for young and middle-aged patients with high activity levels.
Hernigou reported a significant difference between short- and medium-term and long-term application results for ceramic-type prostheses. In the first 5 years, the wear rate was 0.04 mm/year for zirconia prosthesis and 0.08 mm/year for alumina prosthesis, while at 5-10 years, the wear rate was 0.15 mm/year for zirconia prosthesis and 0.08 mm/year for alumina prosthesis [4]; ceramic head fragmentation is a feared complication, and increasing the ceramic head diameter to 32 cm significantly reduces the complication of ceramic head fragmentation. No dislocation, fracture or loosening of the prosthesis was found in this group of patients, but its long-term prosthetic survival rate remains to be observed due to the short follow-up period.
3.2 Proper surgical technique is an important factor in clinical outcomes.
Due to the characteristics of the ceramic prosthesis itself, the correct surgical operation technique and the choice of prosthesis position are important factors affecting the long-term results of the surgery; therefore, the following points should be noted in the surgical operation: (1) remove the hyperplastic bone at the edge of the acetabulum to prevent any possible impingement of the prosthesis; (2) the abduction angle of the acetabular prosthesis should be placed at 45-55 degrees to increase the stress area of the femoral head and The maximum stress is easily transmitted during abduction; the acetabular anterior tilt angle is slightly increased and placed at 15-20 degrees because there is no posterior strengthening to prevent posterior dislocation. (3) Apply a trial mold of the prosthetic liner, and replace the ceramic liner when the position of the femoral head prosthesis and the acetabular prosthesis are considered to fit accurately to ensure the success of the surgery; (4) When placing the femoral head prosthesis on the neck of the prosthesis, pay special attention to the close fit between the two, otherwise stress concentration will occur in the ceramic head, leading to prosthesis fracture. (5) The three anti-rotation nails on the surface of the metal cup should be placed on the sciatic, pubic, and iliac bodies, otherwise they are prone to acetabular fracture. 2 cases in this group resulted in acetabular fracture due to improper placement and were bedridden for 8 weeks after surgery, and no loosening or displacement of the prosthesis was seen during the follow-up period.
In conclusion, ceramic-ceramic joint replacement for the treatment of aseptic necrosis of the femoral head in young and middle-aged people is more suitable for young and middle-aged patients with a high activity level because of its exact effect, less complications and correspondingly longer prosthesis life.
References
[1] Yang Shuhua, Xiao Baojun, Li Jin, et al. Clinical application observation of ceramic head-to-ceramic acetabulum and ceramic head-to-polyethylene acetabular hip arthroplasty [J]. Chinese Journal of Orthopaedic Surgery, 2003;11(6):370-372.
[2] Liu F, Fan WM, Waddell JP. Long-term follow-up of the Zirconia ceramic head-polyethylene total hip joint [J]. Chinese Journal of Orthopaedic Surgery, 2005;13(5):327-329.
[3] Oonishi, H. Clinical experience with ceramics in total hip replacement [J]. Clin Orthop 2000; 379:77-79.
[4] Henigou P, Bahrami T. Zirconia and alumina ceramics in comparison with stainless-steel heads: polyethylene wear after a minimum ten year follow-up[ J]. J Bone Joint Surg (Br) 2003; 85(4):504-507.