Published online Nov 18, 2015. doi: 10.5312/wjo.v6.i10.812
Peer-review started: July 1, 2015
First decision: August 6, 2015
Revised: August 21, 2015
Accepted: September 25, 2015
Article in press: September 28, 2015
Published online: November 18, 2015
Squeaking is a well-recognized complication for hard-on-hard bearings. The nature of squeaking is not yet completely understood however it is considered a multifactorial phenomenon. Patient, implant, and surgical factors play a role in squeaking. It is believed that mechanisms damaging the fluid film lubrication in which these bearings function optimally have a critical role. Such mechanisms include edge loading, stripe wear, impingement, third body particles and ceramic fracture. The resonance of metallic parts can produce noise in the human audible range hence the implant metallurgic composition and design may play a role. Implant positioning can facilitate impingement and edge loading enhancing the occurrence of squeaking. The recent introduction of large heads (> 36 mm) 4th generation ceramic-on-ceramic bearing may accentuate the conditions facilitating noise formation; however the current literature is insufficient. Clinically, squeaking may manifest in extreme hip positions or during normal gait cycle however it is rarely associated with pain. Evaluations of patients with squeaking include clinical and radiographic assessments. Computer tomography is recommended as it can better reveal ceramic breakage and implant malposition. The treatments for most squeaking patients include reassurance and activity modification. However for some, noise can be a problem, requiring further surgical intervention. In the occurrence of ceramic fracture, implant failure, extreme components malposition, instability and impingement, surgery should be advised. This review will aim to discuss the current literature regarding squeaking.
Core tip: Ceramic-on-ceramic bearings can reduce osteolysis and wear, however they can make noise. Squeaking is multifactorial phenomenon and is associated with patient, implant and surgical factors. Ceramic-on-ceramic bearings function best under well lubricated conditions and hindrance to these conditions such as edge loading and stripe wear may produce vibrations, which resonate through the implants metal component producing an audible noise. Mostly, squeaking is a benign phenomenon however it has a psychological effect on patients. Clinical and radiographic evaluations may reveal pathology that requires further surgery however for most, activity modification and reassurance is the treatment.