Aims. In the UK, the agricultural, military, and construction sectors have stringent rules about the use of hearing protection due to the risk of noise-induced hearing loss. Orthopaedic staff may also be at risk due to the use of power tools. The UK Health and Safety Executive (HSE) have clear standards as to what are deemed acceptable occupational levels of noise on A-weighted and C-weighted scales. The aims of this review were to assess the current evidence on the testing of exposure to noise in orthopaedic operating theatres to see if it exceeds these regulations. Methods. A search of PubMed and EMBASE databases was conducted using PRISMA guidelines. The review was registered prospectively in PROSPERO. Studies which assessed the exposure to noise for orthopaedic staff in operating theatres were included. Data about the exposure to noise were extracted from these studies and compared with the A-weighted and C-weighted acceptable levels described in the HSE regulations. Results. A total of 15 studies were deemed eligible. These included a total of 386 orthopaedic operations and the use of 64 orthopaedic instruments. A total of 294 operations (76%) and 45 instruments (70%) exceeded the regulations on an A-weighted scale, and 22% (10 of 46) of operations exceeded the maximum C-weighted peak acceptable level of noise. Noise-induced hearing loss was reported in 28 of 55 orthopaedic staff members (50.9%). Conclusion. Safe levels of noise can be exceeded in orthopaedic operations, and when using orthopaedic instruments. Employers have clear policies about exposure to noise in the workplace but have yet to identify orthopaedic theatres as a potential at-risk area. Orthopaedic staff need education, monitoring, and protection, while employers should consider regular assessments of staff in orthopaedic theatres and offer methods to prevent noise-induced hearing loss. Cite this article: Bone Joint J 2023;105-B(6):602–609

Objectives. Our study aimed to examine not only the incidence but also the impact of noise from two types of total hip replacement articulations: ceramic-on-ceramic and ceramic-on-polyethylene. . Methods . We performed a case-controlled study comparing subjective and objective questionnaire scores of patients receiving a ceramic-on-ceramic or a ceramic-on-polyethylene total hip replacement by a single surgeon. Results. There was a threefold higher incidence of noise from patients in the ceramic-on-ceramic group compared with the control group. The impact of this noise was significant for patients both subjectively and objectively. Conclusions. This study reports a high patient impact of noise from ceramic-on-ceramic total hip replacements. This has led to a change in practice by the principal author. Cite this article: Bone Joint Res 2014;3:183–6

Aims. We evaluated the short-term functional outcome and prevalence of bearing-specific generation of audible noise in 301 patients (336 hips) operated on with fourth generation (Delta) medium diameter head, ceramic-on-ceramic (CoC) total hip arthroplasties (THAs). Patients and Methods. There were 191 female (63%) and 110 male patients (37%) with a mean age of 61 years (29 to 78) and mean follow-up of 2.1 years (1.3 to 3.4). Patients completed three questionnaires: Oxford Hip Score (OHS), Research and Development 36-item health survey (RAND-36) and a noise-specific symptom questionnaire. Plain radiographs were also analysed. A total of three hips (0.9%) were revised. . Results. There were 52 patients (54 hips, 17%) who reported noise, and in 25 (48%) of them the noise was frequently heard. In the multiple regression analysis, the only independent risk factor for noise was a specific THA brand, with a threefold increased risk (95% confidence intervals 1.39 to 6.45, p = 0.005) of noise compared with the reference THA brand. Patients with noisy hips had lower median OHS (43 versus 46.5, p = 0.002) and their physical functioning (p = 0.021) subscale in RAND-36 was reduced. Conclusion. Noise was surprisingly common in this population. Cite this article: Bone Joint J 2017;99-B:44–50

Industries such as agriculture, construction and military have stringent rules about hearing protection due to the risk of noise induced hearing loss (NIHL). Due to the use of power tools, orthopaedic staff may be at risk of the same condition. The UK Health and Safety Executive (HSE) have clear standards as to what is deemed acceptable occupational noise levels on an A-weighted and C weighted scale. This review is aimed to assess evidence on noise exposure testing within Orthopaedic theatres to see if it exceeds the HSE regulations. A targeted search of online databases PUBMED and EMBASE was conducted using Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) principles. This review was registered prospectively in PROSPERO. An eligibility criterion identifying clinical studies which assessed noise exposure for Orthopaedic staff in theatres were included. Noise exposure data was extracted from these studies and a comparison was made with A weighted and C weighted acceptable exposure levels as quoted in the HSE regulations. Fourteen papers were deemed eligible, which reviewed 133 Orthopaedic operations and 64 Orthopaedic instruments. In total, 61% (81 of 132) of Orthopaedic operations and 70% (45 of 64) of instruments exceeded the noise regulations on an A weighted scale. 22% (10 of 46) of operations exceeded the maximum C weighted peak acceptable noise level. Orthopaedic instruments and operations can exceed safe occupational noise levels. NHS Trusts have clear policies about noise exposure in the workplace but have yet to identify Orthopaedic theatres as a potential at risk area. Orthopaedic staff need education, monitoring and protection whereas Employers and Occupational Health should consider assessments to identify at risk staff in Orthopaedic theatres and offer preventative methods from NIHL

Noise induced hearing loss (NIHL) is a common cause of preventable deafness in adults and exposure to loud noise at work is a significant risk factor for its development. In order to protect the hearing of workers in the U.K., the Health and Safety Executive (HSE), on behalf of the Department for Work and Pensions, established the Control of Noise at Work Regulations (2005). The objectives of this study were to define the levels of noise exposure for the surgeon, assistant, scrub nurse and anaesthetist during total hip and knee arthroplasty surgery. In addition, we sought to determine whether the noise exposure during these procedures reaches or exceeds the action values set out by the U.K. Noise at Work Regulations (2005). To our knowledge no real-time assessment of personal noise exposure has been performed simultaneously on multiple members of the theatre team during arthroplasty surgery. Individual noise exposure during arthroplasty hip and knee surgery was recorded using a personal noise dosemeter system model 22 (DM22) (Pulsar instruments, Filey, U.K.). Recordings were taken real-time during five separate theatre sessions. Each theatre session included two arthroplasty procedures and lasted approximately 4hrs. Personal noise exposure was expressed in terms of peak sound pressure and an average noise exposure over an 8-hour time-period to reflect the noise experienced by the ear over a working day. In all three sessions involving total hip replacement surgery the peak sound pressure, for the operating surgeon, exceeded the exposure action values set out by the U.K. Noise at Work Regulations. Theatre sessions involving total knee replacement surgery did not exceed any exposure action values. The peak sound pressures experienced during total hip replacement surgery are too high and mandate that the surgeon should be provided with appropriate hearing protection. In addition, if the upper exposure action value is routinely exceeded then the theatre should be designated a hearing protection zone

The subject of noise in the operating theatre was recognized as early as 1972 and has been compared to noise levels on a busy highway. While noise-induced hearing loss in orthopaedic surgery specifically has been recognized as early as the 1990s, it remains poorly studied. As a result, there has been renewed focus in this occupational hazard. Noise level is typically measured in decibels (dB), whereas noise adjusted for human perception uses A-weighted sound levels and is expressed in dBA. Mean operating theatre noise levels range between 51 and 75 dBA, with peak levels between 80 and 119 dBA. The greatest sources of noise emanate from powered surgical instruments, which can exceed levels as high as 140 dBA. Newer technology, such as robotic-assisted systems, contribute a potential new source of noise. This article is a narrative review of the deleterious effects of prolonged noise exposure, including noise-induced hearing loss in the operating theatre team and the patient, intraoperative miscommunication, and increased cognitive load and stress, all of which impact the surgical team’s overall performance. Interventions to mitigate the effects of noise exposure include the use of quieter surgical equipment, the implementation of sound-absorbing personal protective equipment, or changes in communication protocols. Future research endeavours should use advanced research methods and embrace technological innovations to proactively mitigate the effects of operating theatre noise. Cite this article: Bone Joint J 2024;106-B(10):1039–1043

Ceramic-on-ceramic (CoC) total hip arthroplasty (THA) can produce articular noise during the normal activities, generating discomfort to the patient. THA noise has to be investigated also as a potential predictor and a clinical sign of prosthetic failure. An observational study has been carried out to characterize the noise in CoC cementless THA, and to analyze the related factors. A total of 46 patients with noisy hip have been enrolled in 38 months, within the follow-up protocol normally applied for the early diagnosis of ceramic liner fracture [1]. Noise recording was based on a high-quality audible recorder (mod. LS 3, Olympus, Japan) and a portable ultrasonic transducer (mod USB AE 1ch, PAC, USA). The sensors for noise recording were applied to the hip of the patient during a sequence of repeatable motorial activities (forward and backward walking, squat, sit in a chair, flexion and extension of the leg). Sessions were also video-recorded to associate the noise emission to the specific movements. Each noise event was initially identified by the operator and therefore classified by comparison to the spectral characteristics (duration, intensity and frequency) of the main noise types. Number and spectral characteristics of noise events were obtained and correlated to the factors describing the clinical status of the patient, the surgical approach, the prosthetic device implanted. The study investigated also the noise as a sign of implant failure, by comparison with the total number of implants failed in the cohort during the study. We observed three types of noise with the main spectral characteristics in agreement to the literature: clicking, squeaking and popping. Among the identified types of noise, squeaking showed the longest duration and the highest amplitude. The 63% of hip presented the emission of just one type of noise, while the remaining a mix of types. The movement with the highest presence of noise was walking, followed by squat. Correlation was found between the noise type and the dimension of the ceramic head (p<0.001), with the sizes of 32 mm more affected by squeaking that the smaller one. Squeaking appeared before during the follow-up than the other types of noise. The 35% (16/46) of the noisy hips were revised during the study. Among the revised hips, the 81% (13/16) were affected by impingement and/or severe damage of the prosthetic components. The antiversion of the cup (p=0.008), the presence of debris in the synovial fluid (p=0.021) and the average frequency of squeaking (p=0.006) were significant predictors for the revision, but it has to be mentioned that the squeaking data was obtained on a small subset of revised patients. Ultrasonic analysis did not show significant correlations. The study presented and validated an experimental procedure to analyze noisy hips in clinical trials. Noise is confirmed to be a significant parameter in the follow-up evaluation of ceramic THA

Purpose of study. To determine the onset, incidence and associated symptoms of adverse noise emissions following total hip arthroplasty (THA) with ceramic-on-ceramic (CoC) bearing surfaces. Methods. 50 Sequential CoC THA's (45 patients) performed by a single surgeon were interviewed telephonically at an average post-operative period of 12 months. The same group was re-interviewed telephonically 12 months later. Patients who reported noise emissions at either interview were assessed clinically to determine if symptoms could be reproduced. Results. Of the 45 patients who underwent the first interview, 43 (48 THA's) were re- interviewed. 1 patient had died of an unrelated cause before the second interview, and 2 were not contactable. 2 patients (4%) reported noise emissions at the first interview and 8 (17%) at the second interview. 7 of these 8 patients reported a single or occasional sound. 1 patient reported regular noise emissions and she was the only patient who expressed concern about the noise. None of the patients reported pain or any other symptoms associated with the sound. In none of the cases could the noise be produced during clinical examination. The examiners were unable to demonstrate a correlation between reported noise emissions and radiographic assessment of component orientation. Discussion. When asked specifically about noise emissions, 17% of the patients in our series reported a noise. The majority of these patients (75%) reported no noises when interviewed initially (1 year following surgery), but did report noise emissions when re-interviewed a year later. The incidence as well as onset of reported noise emissions in our series correlates with those reported by other authors. NO DISCLOSURES

The aim of this study was to characterise noise associated with ceramic-on-ceramic total hip arthroplasty (THA). A questionnaire was constructed to assess noise associated with THA. 116 patients responded. All had ceramic-on-ceramic hybrid THA at Glasgow Royal Infirmary between 2005 and 2007 using a Trident prosthesis and Exeter stem. Oxford Hip Questionnaires (OHS) were also completed by the patients. 16.4% of respondents reported noise associated with their ceramic hip. The vast majority reported onset at least 1 year after implantation. The most common noise types were ‘clicking’ (47%) or ‘grinding’ (42%), while ‘squeaking’ was least frequently reported (11%). Noise was most commonly brought on by bending and during sit to stand movements. No correlation was identified between the incidence of noise and any patient specific factor or demographic variable. The mean OHS at questionnaire follow-up was 39 and there was no significant difference in OHS when comparing noisy and silent hips (p=0.65). Only 1 patient limited social or recreational activities and overall patients felt the noise had minimal effect on their quality of life. Acetabular component inclination angles were compared on post-operative x-rays. There was no significant difference (p=0.51) in inclination angles of the noisy (47.1°±6.3°, range 30–57°) and silent hips (47.8°±6.1°, range 35–68°). The groups were further analysed for deviation out with the desirable inclination range of 40–45°. Of the noisy hips, a total of 73% were out with this range compared to 63% in the silent hip group. The incidence of noise within this ceramic-on-ceramic THA group did not appear to be related to patient specific factors, patient reported outcome (OHS) or acetabular inclination angles. Subjective appraisal of the noise revealed that ‘squeaking’ was not common but patients tended to report ‘clicking’ and ‘grinding’ more. The precipitation of noise with bending activities reinforces a possible mechanical cause

Noise generation has been reported with ceramic-on-ceramic articulations in total hip replacement (THR). This study evaluated 208 consecutive Delta Motion THRs at a mean follow-up of 21 months (12 to 35). There were 141 women and 67 men with a mean age of 59 years (22 to 84). Patients were reviewed clinically and radiologically, and the incidence of noise was determined using a newly described assessment method. Noise production was examined against range of movement, ligamentous laxity, patient-reported outcome scores, activity level and orientation of the acetabular component. There were 143 silent hips (69%), 22 (11%) with noises other than squeaking, 17 (8%) with unreproducible squeaking and 26 (13%) with reproducible squeaking. Hips with reproducible squeaking had a greater mean range of movement (p < 0.001) and mean ligament laxity (p = 0.004), smaller median head size (p = 0.01) and decreased mean acetabular component inclination (p = 0.02) and anteversion angle (p = 0.02) compared with the other groups. There was no relationship between squeaking and age (p = 0.13), height (p = 0.263), weight (p = 0.333), body mass index (p = 0.643), gender (p = 0.07) or patient outcome score (p = 0.422). There were no revisions during follow-up. Despite the surprisingly high incidence of squeaking, all patients remain satisfied with their hip replacement. Cite this article: Bone Joint J 2013;95-B:160–5

Surgeons working in orthopaedic operating theatres are exposed to significant noise pollution due to the use of powered instruments. This may carry a risk of noise-induced hearing loss (NIHL). This study was designed to quantify the noise exposure experienced by orthopaedic surgeons and establish whether this breaches occupational health guidelines for workplace noise exposure. A sound dosimeter was worn by the operating surgeon during 3 total hip replacements and 2 total knee replacements. A timed record of the procedures was kept concurrently. Noise levels experienced during each part of the procedure were measured and total noise exposures calculated. Quantified noise exposures were compared with occupational health guidelines. Noise exposure in total hip replacement averaged 4.5% (1.52–6.45%) of the allowed daily dose (average duration 77.28 min). Total knee replacement exposure was 5.74% (4.09–7.39%) of allowed exposure (average duration 69.76min). Maximum sound levels approached, but did not exceed recommended limits of 110 dBA (108.3dBA in total hip replacement and 107.6dBA in total knee replacement). Transient peak sound levels exceeded occupational health maximum limits of 140dB on multiple occasions during surgery. Overall total noise dose during orthopaedic surgery was acceptable, however orthopaedic surgeons experience brief periods of noise exposure in excess of legislated guidelines. This constitutes a noise hazard and carries a significant, but unquantified risk for NIHL

Hard-on-hard bearing surface have been accepted as a valuable alternative for young and active patients needing a hip replacement because these combinations are resistant to wear. Initial development of alumina-on-alumina bearings faced complications such as fractures, and socket loosening. But, with the increasing number of prostheses implanted, noise occurrence appeared as a new complication. The primary aim of the present survey was to quantify the prevalence of having noise in a population receiving alumina-on-alumina hip arthroplasty. Two hundred and eighty-four ceramic-on-ceramic hips were performed in 238 patients (126 males and 112 females) from January 2003 to December 2004. The average age at the index operation was 52.4 ± 13.4 years (range, 13 to 74 years). We used the same type of prosthesis for all patients manufactured in all cases by Ceraver-Osteal. ®. Clearance between femoral and insert was between 20 and 50 microns in order to achieve minimal wear. The survey was conducted by an independent surgeon who did not participated in patients care during the last 6 months of 2007. He interviewed the patients by phone with a standardized questionnaire (appendix) that aimed to assess if noise was present and the characteristics of this noise if present. No suggestion was done on how they could describe the noise and they felt free to use the word that they considered to be the most adapted. Satisfaction was evaluated asking if the patient was very satisfied, satisfied or dissatisfied with its prosthesis. When the noise was present, the X-ray was independently evaluated to assess if sign of component fracture was present. Four patients (six hips) died of unrelated cause during the follow-up. Three patients (three hips) lived outside France and could not be followed (1.3%). Nine patients (ten hips) could not be traced and are considered lost to follow-up (3.8%). Two hundred and twenty-two patients with 265 hips were therefore surveyed. Among these 265 hips, 28 experienced noise generation (10.6%). It was defined as a snap for 6 patients, as a cracking sound by 6, as rustling by 6 patients, as a squeaking by 7 patients (2.6%), a tinkling by 2 patients, one patient was unable to define the sound she felt. No factor related to the patient influenced the occurrence of noise. Twelve patients were dissatisfied with the result of the hip prosthesis, 5 of them experienced noise (41.7%); 210 were satisfied or very satisfied 23 of them experienced noise (11%); this difference was significant (p=0.002). No patients required revision for noise. The origins of noise occurrence are unknown but several hypotheses can be suggested. Squeaking may be due to absence of sufficient lubrication. Other types of noise can be due to microseparation, occult dislocation, impingement between the femoral neck and the acetabular rim but demonstration remain an issue

The link between squeaking and ceramic on ceramic (CoC) bearings has been widely reported in orthopaedic literature and is described as a hard bearing phenomenon. We aim to look at the incidence of noise in CoC bearings compared to Metal on Polyethylene (MoP) bearing, which have yet to be linked to squeaking. We developed a noise characterizing hip questionnaire and sent that along with the Oxford Hip Score (OHS) to 1000 patients; 3:2 ratio of CoC to MoP. 282 CoC patients and 227 MoP patients returned the questions: 509 patients in total. Our patient database provided details on femoral head size and the acetabular inclination angle, for each respondent. 47 (17%) of the CoC hip patients reported noise compared to 19 (8%) of the MoP hip patients (P=0.054). 9 CoC patients and 4 MoP patients reported squeaking, while clicking was the most frequent answer in both groups. 27% patients with noise reported avoiding recreational activities because of it. Patient's with noisy hips scored on average, 5 points worse in the OHS (CoC: P = 0.04 and MoP: P = 0.007) and were on average 5 years younger (CoC: P<0.001 and MoP: P=0.007). No correlation was found between noisy hips and femoral head size or inclination angle. The squeaking hip phenomenon is not exclusive to hard bearing THA. Noise from patient's hips may have social implications and this should be highlighted when consenting a patient for either of these hip procedures. In both implants, we showed there to be a correlation between noise production and a lower OHS. However, longer follow up studies are needed to link noise to a poorly functioning implant

The problem associated with ceramic on ceramic total hip replacement (THR) is audible noise. Squeaking is the most frequently documented sound. The incidence of squeaking has been reported to wide range from 0.7 to 20.9%. Nevertheless there is no study to investigate on incidence of noise in computer assisted THR with ceramic on ceramic bearing. The purpose of this study was to determine the incidence and risks factors associated with noise. We retrospectively reviewed 200 patients (202 hips) whom performed computer assisted THR (Orthopilot, B. Braun, Tuttlingen, Germany) with ceramic on ceramic bearing between March 2009 and August 2012. All procedures underwent uncemented THR with posterior approach by single surgeon. All hips implanted with PLASMACUP and EXIA femoral stem (B. Braun, Tuttlingen, Germany). All cases used BIOLOX DELTA (Ceramtec, AG, Plochingen, Germany) ceramic liner and head. The incidence and type of noise were interviewed by telephone using set of questionnaire. Patient's age, weight, height, body mass index, acetabular cup size, femoral offset size determined from medical record for comparing between silent hips and noisy hips. The acetabular inclination angle, acetabular anteversion angle, femoral offset, hip offset were reviewed to compare difference between silent hips and noisy hips. The audible noise was reported for 13 hips (6.44%). 5 patients (5 hips) reported click (2.47%) and 8 patients (8 hips) squeaked (3.97%). The mean time to first occurrence of click was 13.4 months and squeak was 7.4 months after surgery. Most common frequency of click was less than weekly (60%) and squeak was 1–4 times per week (50%). Most common activity associated with noise was bending; 40% in click and 75% in squeaking. No patients complained for pain or social problem. Moreover, no patient underwent any intervention for the noise. The noise had not self-resolved in any of the patients at last follow up. Age, weight, height and BMI showed no statistically significant difference between silent hips and click hips. In addition, there was also same result between silent hips and squeaking hips. Acetabular cup insert size and femoral offset stem size the results showed that there was no statistically significant difference between silent hips and click hips, also with squeaking hips. Acetabular inclination, angle acetabular anteversion angle, femoral offset, hip offset the results shown that only acetabular anteversion angle differed significantly between silent hips (19.94±7.78 degree) and squeaking hips (13.46±5.54 degree). The results can conclude that incidence of noise after ceramic on ceramic THR with navigation was 6.44 %. Squeaking incidence was 3.97% and click incidence was 2.47%. The only associated squeaking risk factor was cup anteversion angle. In this study, squeaking hip had cup anteversion angle significant less than silent hip

This study assesses the incidence of noise in ceramic on ceramic (COC) bearings compared to metal on polyethylene (MOP) bearings. Noise after MOP implants has rarely been studied and they never been linked to squeaking. We have developed a noise characterising hip questionnaire and sent it along with the Oxford Hip Score (OHS) to 1000 patients; 509 respondents, 282 COC and 227 MOP; median age 63.7 (range 45–92), median follow up 2.9 years (range 6–156 months). 47 (17%) of the COC patients reported noise compared to 19 (8%) of the MOP patients (P=0.048). 9 COC and 4 MOP patients reported their hip noise as squeaking. We found the incidence of squeaking in the COC hips to be 3.2% compared to 1.8% in the MOP hips. Overall, 27% patients with noise reported avoiding recreational activities because of it and patient's with noisy hips scored on average 4 points less in the OHS (COC: P=0.04 and MOP: P =0.007). This is the first study to report squeaking from MOP hip replacements. We therefore believe the squeaking hip phenomenon is not exclusive to hard bearings. Surprisingly, only a small proportion of patients described nose from their as a ‘squeak’. Noisy hip implants may have social implications, and patients should be aware of this. We have shown a relationship between noise and a lower OHS. However, longer follow-up and further study is needed to link noise to a poorly functioning implant

Squeaking in ceramic total hip joint replacements has become a controversial topic. This study aims to document the incidence of squeaking and other noise generation in a single surgeon series for ceramic on ceramic total hip joint replacements. Possible aetiological for squeaking causes are explored. All patients from public and private who received ceramic on ceramic total hip joint replacements (Stryker trident-accolade) from 2002 to 2007 were identified via the New Zealand Joint registry. Following ethics approval all patients were contacted for a phone interview to question as to whether they had noted any noise generation. Patients who demonstrated noise generation were reviewed in clinic for full history and examination. Data including age, sex, weight, primary diagnosis, head size and cup size were obtained from clinical notes. Post operative x-rays were reviewed to analyse cup abduction and version. Forty one ceramic total hip joint replacements in a total of thirty seven patients were reviewed via telephone interviews. Three patients complained of squeaking in the ceramic bearing while one patient complained of a grinding and one other of clicking. Two of the three who had recognised the squeaking were both able to reproduce the squeaking in the clinic room. The third patient was noted to have crepitus from anterior patello-femoral osteoarthritis. There was no statistical difference in age, weight, primary diagnosis or head size. In terms of abduction and version of the acetabular cups that squeaked, one had twenty seven degrees of ante-version and forty seven degrees of abduction and the other fifteen degrees of anteversion and thirty degrees of anteversion. Four cups lay outside the recommended fifteen-thirty five degrees of anteversion and thirty five-fifty five degrees of abduction yet showed no squeaking. Neither patient is troubled by the squeaking and neither would seek revision surgery. The incidence of squeaking in ceramic on ceramic total hip joint replacements appears to be around five percent with a similar number of patients experiencing other noises. The position of the acetabular cup does not appear to be the sole contributor to the noise and other aetiological causes need to be further investigated

Introduction: With ceramic on ceramic bearing surfaces in total hip arthroplasty audible noise is a frequently documented problem. With increasing head size, there is less chance of component-on-component impingement and therefore a decreased risk of chipping, breaking and maybe noise occurrence. Material and Methods: Prospective multicentre follow-up study of n=149 cases (91 males and 58 females). All patients were treated with either 32 or 36mm ceramic on ceramic articulation (Bionit. ®. ) in combination with the non-cemented modular pressfit cup seleXys. ®. (Mathys Ltd Bettlach, Switzerland). There were n=4 patients with bilateral surgery. 56 patients received a 32mm head whereas 93 patients were treated with a 36mm head. In the group with 32 mm head diameter 79% were women, whereas in the 36 mm group only 16% were women. Patients were operated between December 2005 and January 2007. The mean age at surgery was 67.2 years (range, 46.3 – 86.4 years). Mean body mass index was 28.0 kg/m2 (range, 17.1 – 45.4 kg/m2). Patients were followed clinically and radiographically at three and six months, then after one and two years. Results: 5 patients died and 2 patients were lost to follow-up. Only one patient reported squeaking noise immediately after the operation. At the one year follow-up the patient reported a feeling of subluxation and the noise turned into a clicking. The patient had to be revised after 14 months with a polyethylene inlay. No other revisions had taken place. Patients with femoral heads of 32 mm and 36 mm diameter had excellent clinical results after 2 years follow-up for flexion angle, range of motion and Harris Hip Score. The Harris Hip Score increased from a pre-operative mean of 48.7 points to 93.5 points. Hip flex-ion increased from 91° to 113°. The Visual Analogue Scale for pain decreased from 6.7 to 0.9 and VAS for satisfaction increased from 3.2 to 9.3. Conclusion: Compared to other studies the occurrence of noise and resulting revision procedures is very low. We assume that the insertion of bigger heads may reduce this problem and simultaneously allow the patient a better range of motion. The non-cemented modular cup combined with a ceramic inlay and a ceramic femoral head is a safe implant with excellent clinical results after two years

Background/Purpose. Total hip arthroplasties (THAs) with ceramic bearings are widely performed in young, active patients and thus, long-term outcome in these population is important. Moreover, clinical implication of noise, in which most studies focused on ‘squeaking’, remains controversial and one of concerns unsolved associated with the use of ceramic bearings. However, there is little literature regarding the long-term outcomes after THAs using these contemporary ceramic bearings in young patients. Therefore, we performed a long-term study with a minimum follow-up of . 1. 5 years after THAs using contemporary ceramic bearings in young patients with osteonecrosis of the femoral head (ONFH) less than fifty. Materials and Methods. Among sixty patients (71 hips) with a mean age of 39.1 years, 7 patients (7 hips) died and 4 patients (4 hips) were lost before 15-year follow-up. The remaining 60 hips were included in this study with an average follow-up period of 16.3 years (range, 15 to 18). All patients underwent cementless THA using a prosthesis of identical design and a 28-mm third-generation alumina head by single surgeon. The clinical evaluations included the modified Harris hip score (HHS), history of dislocation and noise around the hip joint: Noise was classified into squeaking, clicking, grinding and popping and evaluated at each follow-up. Snapping was excluded through physical examination or ultrasonography. Radiographic analysis was performed regarding notching on the neck of femoral component, loosening and osteolysis. Ceramic fracture and survivorship free from revision were also evaluated. Results. The mean Harris hip score improved from 55.3 to 95.5 points (range, 83 to 100) at the time of the final follow-up. Seventeen patients (34.7%) reported noise around the hip joint: “squeaking” in one and “clicking” in 16 patients. Notching on the neck of femoral component suggesting impingement between neck and ceramic liner was demonstrated in 9 hips (15%) at average of 6.9 years postoperatively and located at 2 to 3.5 mm distal to edge of ceramic head. Although no chip fracture of ceramic ‘liner’ occurred, notching was associated with “clicking” sound (p<0.01). One patient who reported clicking sound underwent a revision THA because of ceramic ‘head’ fracture. Loosening, osteolysis or dislocation was not observed in any hip and survivorship free from revision at 5 years was 98%. Conclusion. Cementless THAs using 28-mm contemporary alumina ceramic head demonstrated excellent long-term outcome in young, active patients with ONFH. Despite this encouraging result, however, we remain concerned about ‘clicking’ sound, because we did observe it associated with notching on the neck of stem. Acknowledgement. This work was supported by Institute for Information & communications Technology Promotion (IITP) grant funded by the Korea government (MSIP) (#B0101-14-1081)

Introduction: Increasing numbers and incidence rates of noisy (squeaking, scratching, clicking) ceramic-on-ceramic (CoC) total hip arthroplasties (THA) are being reported. The etiology seems to always involve stripe wear producing a stick-slip effect in the bearing which excites vibrations. As stripe wear is also found in silent CoC bearings, a theory has been developed that the vibrations become audible only via amplification through the vibrating stem (bell-clapper theory). This was supported by showing that the excitation frequency and the resonance frequency of the plain stem are similar. However, stem resonance in-vivo would be influenced by the periprosthetic bone damping and transmitting stem vibrations. Thus, if the bell-clapper theory were true, noisy CoC hips should show periprosthetic bone different to silent hips. This study compares stem fit& fill and periprosthetic bone between noisy and silent CoC hips. Methods: In a consecutive series of 186 primary CoC hips with identical stems, cups (Stryker ABG-II) and femoral heads (Alumina V40, 28mm) a survey identified 38 noisy hips (incidence rate: 20.4%, squeakers: n=23). Stem fit& fill and cortical wall thickness (CWT, medial and lateral) were measured on post-op AP x-rays according to the method of Kim & Kim. Measurements were repeated by a single blinded observer in a control group of silent hips matched for gender, age, stem size and follow-up time (4.6yrs). Fit& fill and CWT were compared between the noisy and silent group at proximal, mid-stem and distal level and on the medial and lateral side. Results: The endosteal canal width was equal in noisy (N) and silent hips (S) at all levels (e.g. proximal: N=39.7+/−5.5mm, S=41.3+/−5.7mm). On the lateral side also cortical wall thickness (CWT) was the same at all levels (e.g. proximal: N=2.0+/−0.8mm, S=1.9+/−0.9mm). However, on the medial side, noisy hips had higher CWT at proximal (N=4.9+/−2.8mm, S=3.0+/−2.1mm, p< 0.01) and mid-stem level (N=6.2+/−2.1mm, N=4.6+/−1.7mm, p< 0.001). Also Fit& fill was slightly higher (proximal: N=66%, S=62%; mid-stem: N=63%, S=59%, p< 0.05). Differences and significance levels increased when only squeakers were considered. Discussion: Despite equal endosteal canal widths and lateral cortical wall thickness for noisy and silent hips, noisy hips had sign. thicker medial walls at proximal (+63%) and mid-stem level (+35%) where also fit& fill was higher. This gives evidence that periprosthetic bone (PPB) may play a role in the development of audible noise in CoC hips by providing particular conditions of support, damping and transmission for an oscillating stem which influences noise frequency and intensity. Comparing PPB at different time points indicated that the differences are less due to post-op remodeling but more to pre-op conditions, surgical canal preparation and possibly stem design. The findings shall be verified by a DEXA study

Monitoring the performance of hip replacements post-operatively is tedious and costly, necessitating radiological examinations as well as other specialized examinations such as whole blood metal ion levels. In an effort to control escalating costs, we conducted an ethically approved clinical trial to assess the efficacy of basic acoustic monitoring equipment to asses these implants. Method. An electronic stethoscope was successfully used to record sounds from the hips of participants with different bearing surfaces. The sounds were recorded while conducting a standardized movement sequence. A 5th order Savitzky-Golay filter with a window width of 21 points was used to remove background noise. The recordings were also listened to by ear and three primary classes of sounds were identified. Frequency components contained in the classes were identified using spectrograms and Welch power density spectra. The sounds were correlated with different patient factors including component positioning, BMI and length of time that the implant was in situ. The skewness and kurtosis of the power spectra were calculated and found to be different for each class. Further frequency analysis was conducted with the aid of the discrete wavelet transform. This met with some success as different frequency levels were found in each sound class. Results. All bearing surfaces produced some noise. The most sounds were produced by the ceramic-on-metal group, even though not in the audible range, and those participants with a body mass index in the obese range. Sounds were also detected in the ceramic-on-polyethylene implants. However, no consistent links between these factors and the sounds produced could be identified. Specifically, the lack of correlation between sound occurrence and length of implantation indicates that this technique is not useful in predicting possible failures or future complications in real time. Conclusions. The sounds themselves did not immediately reveal any information about the implants. This method was deemed impractical as a real-time diagnostic technique. Our study though has demonstrated that inexpensive acoustic monitoring devices can monitor noise emissions. Our data needs to be refined to make these investigations reliable and clinically relevant