HXLPE was developed to reduce wear in conventional PE liners. Meanwhile, the incidence and severity of osteolysis secondary to wear would also be decreased . Mutimer et al.  reported that HXLPE had a lower revision rate compared with traditional PE with an average follow-up period of 5.5 years. In addition, the use of ceramic heads reduces wear rates as well . The reported wear rate of CoHXLPE was 0.04–0.20 mm per year . But in the current case, the HXLPE was penetrated only 3 years after primary THA, which led to further wear between ceramic head and acetabular shell. To the author’s knowledge, this is the first report of early failure for wear after CoHXLPE THA.
The wear of HXLPE after THA is multifactorial, such as body weight, high activity level, large abduction angle of the cup and decrease of femoral offset [8,9,10]. What’s more, DDH is also related to the wear of HXLPE. In Crowe III and IV DDH, soft tissue around the hip contractures because the femoral head is chronically dislocated. When the rotation center moves down or returns to the true acetabulum, the tension of the soft tissue may become much higher, which may accelerate the wear of HXLPE . In the current case, the patient’s DDH classification was Crowe III and failure mechanism may be ascribed to the high tension of abductor after reduction of DDH, which eventually led to the rapidly superolateral eccentric wear of the HXLPE.
With the image test, the early wear of the prosthesis can be found. Wear debris production may lead to ARMD, which will worsen the fibrosis and necrosis of soft tissue, the erosion of metal and the loosening of prosthesis . Thus, once eccentric wear occurs, the patient must stop weight-bearing to prevent the accelerated wear and osteolysis.
Revision THA is the definitive treatment for the wear of PE . However, whether a well-fixed acetabular cup should be revised or not, there is still no general consensus or specific guideline. Restrepo et al.  advocated that the acetabular component should be revised when the femoral head penetrated the liner and damaged the metal cup, or the locking mechanism was damaged, or the component was malpositioned which may lead to the instability of the revision. Besides, Maloney et al. [15,16,17] divided the uncemented cups into three types: I. The cup was radiographically stable (following six principles must be met: (1) the implant should be a modular implant, (2) the implant should have an acceptable track record, (3) the cup was in good position, (4) the locking mechanism could not be damaged, (5) the metal shell was intact, and (6) the thickness of the polyethylene liner replacement must be adequat.); II. The cup was radiographically stable (the shell was radiographically stable, but any of the previous principles were not met.); III. The cup was radiographically unstable. As to type I, a liner exchange can be performed. However, component should be revised in type II and type III. Besides, graft may or may not be used in all types. However, even with perfect preoperative assessment, it should be noted that intraoperative testing of component positioning and stability is also essential. In the current patient, although the cup was well-fixed, it had been worn inside. Thus, we performed acetabular revision and ceramic femoral head and HXLPE exchange. The revision obtained satisfactory early outcome.
Difficult reduction during primary THA, especially for DDH, can result in higher abductor tension, which may lead to early eccentric wear of the prosthesis. Whenever eccentric wear of HXLPE liner was found, weight-bearing must be stopped to avoid the accelerated wear and ARMD. Partial or total revision THA is the primary treatment for such wear of HXLPE. A careful assessment of preoperative radiographs and intraoperative testing are imperative to avoid subsequent dislocation and loosening.