While alumina ceramic-ceramic THA has been performed in the US for more than 12 years, the phenomenon of frequent, clinically reproducible squeaking is relatively new. The current study investigates the influence of implant design on the incidence of squeaking.

We reviewed implant information on 1275 consecutive revision THAs performed from 10/2002 through 10/2007 to identify any patients who had complained of squeaking or grinding. We also identified, 2778 consecutive primary ceramicceramic THA. Of these, we reviewed the clinical records of 1,039 patients (37%) to date. Any patient complaint of squeaking or grinding at the time of an office visit or by phone interview was recorded. Hips were divided into group 1: flush mounted ceramic liner; group 2a: recessed ceramic liner mated with a stem made of TiAlV and using a 12/14 neck taper; and group 2b: recessed ceramic liner mated with a stem made of a beta titanium alloy comprised of 12% molybdenum, 6% Zirconium, and 2% Iron and using a neck taper smaller than a 12/14 taper.

Of the revision THAs, 5 hips (0.4%) were in patients who had complained of squeaking or grinding. All 5 hips had a recessed, metal-backed ceramic liner and evidence of metallosis. In primary THAs, Group 2b had statistically significantly (p=0.04) more squeaking (7.6%) than group 2a (3.2%) which had statistically significantly (p=0.002) more squeaking than group 1 (0.6%).

Squeaking following ceramic-ceramic THA is associated with use of a recessed metal-backed ceramic liner in combination with a femoral component made of a betatitanium alloy and using a relatively small head-neck taper. Since all revised hips in our study had metallosis, it is possible that metal debris is adversely affecting the bearing and that the elevated metal rim combined with a small head neck taper and the beta-titanium alloy contribute to this problem. Use of bearings with a flush-mounted ceramic liner mated with femoral components made of TiAlV and using a 12/14 taper appears to be prudent.

Alumina ceramic-ceramic bearings have the benefit of very low wear and studies showing the complete absence of osteolysis during the first decade of close study. However, good results depend on several critical factors including surgical exposure, surgical technique, component placement, and choice of component design. The following abstract discusses our experience with several of these factors.

Initially, there were concerns that the use of ceramic-ceramic bearings would lead to a higher incidence of hip dislocation since the bearings have fewer femoral head-length choices and the absence of lipped-liners. In our prospective study of 418 hips the incidence of hip dislocation at 1 to 10 year followup is 0.5% (2/418). This experience suggests that the use of alumina ceramic-ceramic bearings is not associated with an increased incidence of dislocation.

More recently, concerns about squeaking of alumina ceramic-ceramic bearings have been reported, particularly from centers in the United States. To investigate this issue, we reviewed information on 1275 consecutive revision THAs and 1039 consecutive primary ceramic-ceramic THA that had been performed at two institutions between 1996 and 2007. To identify the influence of the implant design on the incidence of squeaking we divided the primary hips into three groups with group 1: flush mounted ceramic liner; group 2a: recessed ceramic liner mated with a stem made of TiAlV; and group 2b: recessed ceramic liner mated with a stem made of a beta titanium alloy comprised of 12% molybdenum, 6% Zirconium, and 2% Iron.

Analysis of the 1275 revision hips revealed 5 alumina ceramic-ceramic hips in patients who complained of squeaking or grinding. All 5 hips were designs that included a ceramic liner that was recessed inside of an elevated metal rim. All 5 hips also demonstrated metallosis at the time of revision.

In primary THA, Group 2b had statistically significantly more squeaking (9 of 118) than group 2a (10 of 321) which had statistically significantly more squeaking than group 1 (6 of 700). In addition, the severity of squeaking between the groups was qualitatively different. Patients in Group 2b who complained of squeaking would often experience squeaking frequently throughout the day and could be demonstrated in the physician’s office. By contrast, patients in Group 1 who noted squeaking stated that the hip squeaked once a day to once a year. No patient in Group 1 complained of frequent squeaking or could demonstrate squeaking in the physicians’ office. Further, joint fluid analysis from a patient in Group 2b who complained of squeaking revealed metal from both the femoral (Molybdenum) and acetabular (Aluminum) components.

As reported in another abstract at this meeting, 10 year survivorship of flush-mounted alumina ceramic-ceramic THA is 98.4% (95% confidence interval 97.1–100%) and no patient in that prospective clinical studies demonstrated radiographic evidence of osteolysis or wear.

These experiences demonstrate that THA using alumina ceramic-ceramic is extremely reliable with low revision and dislocation rates and an absence of osteolysis. Significant squeaking is not associated with flush-mounted alumina ceramic liners and is clearly associated with elevated metal rims and metallosis. Finally, squeaking is statistically significantly associated with femoral components made of a beta titanium alloy consisting of Titanium, Molybdenum, Aluminum, and Iron.