The Journal of Arthroplasty xxx (2014) xxx–xxx

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Gross Trunnion Failure After Primary Total Hip Arthroplasty Samik Banerjee, MD, Jeffrey J. Cherian, DO, James V. Bono, MD, Steven M. Kurtz, PHD, Rudolph Geesink, MD, R. Michael Meneghini, MD, Ronald E. Delanois, MD, Michael A. Mont, MD a r t i c l e

i n f o

Article history: Received 19 September 2014 Accepted 13 November 2014 Available online xxxx Keywords: trunnion total hip arthroplasty fracture trunnionosis wear failure

a b s t r a c t Unfavorable outcomes from trunnion fretting and corrosion damage have been reported in the literature, gross failures of tapers in primary total hip arthroplasties have been less frequently reported. We report on 5 patients, who presented with gross trunnion failures of modular metal-on-polyethylene or ceramic-on-polyethylene bearings from 5 implant manufacturers, all necessitating revision surgery. None of these patients had an antecedent history of trauma, and the majority presented with pain or instability. No common factor was identified that may be predictive of these type of failures. Since there were 5 different stem designs, this suggests that it may be a rare generic phenomenon occurring with multiple designs. Currently, further investigations are necessary, including retrieval analysis, to identify risk factors that may predispose to such failures. © 2014 Elsevier Inc. All rights reserved.

The Morse taper was originally developed to obtain reliable connections between two rotating machine components in the mid-eighteenth century [1]. It was based on the principle of a cone-in-cone which allowed stable fixation through compression of the walls of the bore (socket) as the trunnion is driven into it. Although it has been successfully used in various machines such as drill presses, milling machines, cutting tools, and power devices, one important application has been in lower extremity total joint arthroplasty for joining modular hip and knee components, in order to provide accurate alignment and secure frictional fixation. The purported benefits of modularity include adjustments in leg-length discrepancies, restoration of hip offsets, optimization of soft tissue tension, and easier exposure during revision surgeries. Under normal mechanical loading conditions, the interface between the mating surfaces of the modular taper junctions is mechanically stable to prevent dissociation or other unwarranted effects such as fretting damage, wear, loosening, or fracture. Although the intimate conical connection between the trunnion and the bore allows firm contact and prevents construct disassembly, small gaps may be present between the mating surfaces due to manufacturing tolerances in the male and female cone geometries. These microscopic gaps or crevices may allow ingress of fluid and micro-movement (fretting) during cyclical mechanical loading leading to disruption of the protective passive surface oxide layer and increasing the susceptibility of the metal surfaces to mechanically assisted crevice corrosion (MACC) [2]. Multiple factors including taper design, metal-alloy

The Conflict of Interest statement associated with this article can be found at http:// dx.doi.org/10.1016/j.arth.2014.11.023. Reprint requests: Michael A. Mont, M.D., Director, Center for Joint Preservation and Replacement, Rubin Institute for Advanced Orthopedics, Sinai Hospital of Baltimore, 2401 West Belvedere Avenue, Baltimore, MD 21215.

mismatch, malpositioning, taper design incongruencies, as well as patient and surgical factors such as tissue interpositioning and/or failure to achieve initial engagement have been reportedly associated with the development of MACC [2–5]. These mechanical and corrosive mechanisms acting at the trunnion (male taper) and the bore (socket or female taper) are increasingly believed to result in the release of particulate debris and metal ions, which may lead to formation adverse local tissue reactions. In addition to these adverse tissue reactions, MACC can potentially lead to mechanical failures at the taper junction [5]. Although unfavorable outcomes from the release of metal ions from trunnion wear have been extensively reported in the orthopedic literature,[6–8] gross failures of tapers (for example substantial trunnion material loss, disassembly, or fractures) in primary total hip arthroplasties have been less frequently reported in only a few case reports [4,5,9]. Therefore, we have reviewed the clinico-radiographic factors that were associated with adverse prosthetic mechanical consequences of gross material trunnion failure or fracture, in a case series of patients who had undergone modular primary total hip arthroplasties. Specifically, we have described the: (1) patient demographics; (2) clinical presentation; (3) radiographic factors; (4) implant details; (5) intraoperative details; and (6) complications. Methods A case series of 5 patients, involving 5 different stem designs from 5 different institutions were reviewed. Gross trunnion failures (GTFs) are defined as trunnions that, upon revision, exhibited gross loss of volume and/or material or a fracture. Operative reports, office charts, electronic health records, implant records, and radiographic images were analyzed to identify the demographics, description of trunnion failure, and other patient-reported details. Various demographic factors such as age,

http://dx.doi.org/10.1016/j.arth.2014.11.023 0883-5403/© 2014 Elsevier Inc. All rights reserved.

Please cite this article as: Banerjee S, et al, Gross Trunnion Failure After Primary Total Hip Arthroplasty, J Arthroplasty (2014), http://dx.doi.org/ 10.1016/j.arth.2014.11.023

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gender, body mass index, comorbidities, presenting symptoms, preoperative diagnoses, and duration of follow-up were analyzed. When available, radiographs as well as intra-operative photographs and implant analysis reports were also reviewed to classify patients according to the type of morphological trunnion failure. Implant details including stem types, offsets used, femoral head diameters, taper types, neck lengths, and acetabular shell details including shell diameters were obtained from the implant records and tabulated. Intra-operative details including the presence of metallosis, pseudotumors, and adverse local soft tissue lesions were recorded. All implants were examined visually for gross wear, material loss, and deformation within the taper or for the presence of fracture. In addition, peri-operative and post-operative details of the revision surgery, including the occurrence of postoperative complications were documented. Serum metal ion levels (e.g. cobalt, chromium, and/or titanium) were evaluated when these were performed prior to revision surgery. All radiographic measurements were obtained after calibration using the femoral head size documented from intra-operative records. Cup inclination and anteversion, femoral offset, and stem alignment were measured from pre-operative radiographs using digital software when available. The acetabular inclination was measured by determining the angle subtended between the line drawn across the inferior points of the ischial tuberosities and the line drawn through the superior and inferior points of the ellipse of the face of the acetabular shell projected on a supine antero-posterior radiograph. The acetabular anteversion was calculated using the formula as described by Pradhan [10] The femoral offset was measured from the radiographs by measuring the perpendicular distance between the anatomic axis of the femur and the center of the femoral head. Radiographs were also reviewed for the presence and location of femoral or acetabular osteolysis. Approval of the respective institutional review boards were obtained prior to the study. All data collected were integrated into an Excel spreadsheet (Excel, Microsoft Corporation, Redmond, Washington) for tabulation and further analysis. Results Each Case will be Individually Described: Case 1 A 67 year-old man, received a left primary cementless total hip arthroplasty in February, 2006 for a pre-operative diagnosis of primary osteoarthritis. His past medical history included obesity with a body mass index (BMI) of 40 kg/m 2. The femoral implant used was a cementless 16 ML extended offset taper stem (Zimmer Orthopaedics, Warsaw, Indiana), while the acetabular component used during the index procedure was a cementless Trilogy cup (Zimmer Orthopaedics, Warsaw, Indiana) of size 60 millimeters. The femoral head component was a 32 millimeters cobalt-chromium skirted head with a +4 millimeters neck length. The liner used was a Longevity (Zimmer Orthopaedics, Warsaw, Indiana) highly cross-linked polyethylene bearing. Immediate post-operative radiographs showed that the components were in satisfactory position (acetabular angle of 45 degrees and an anteversion angle of 20 degrees) and his post-operative course was uneventful. By three months, he had returned to his usual activities. However, 8 years later, he presented to the office complaining of marked acute onset of non-radiating left hip and groin pain while getting in to his car. He was unable to bear any weight thereafter. Radiographs revealed disassociation of the trunnion from the femoral head component and it was indicated for exploration/revision surgery (See Fig. 1A). Metal ion levels performed prior to revision surgery were found and revealed a cobalt ion level of 0.5 ng/L and chromium of 2.9 ng/L. Intra-operatively, the trunnion was found to be malformed with wear of the antero-superior and postero-superior surface and grooving of the inferior surface (See Fig. 1B and C). Minimal peripheral osteolysis was found around the acetabulum and proximal femur on

Fig. 1. (A), (B), and (C) Initial radiographic images on presentation (patient 1) showing dissociation of the trunnion from the femoral head, and explanted femoral stem demonstrating gross trunnion failure.

exploration. In addition, there was substantial black débris suggestive of metallosis in the periprosthetic tissues. The proximal femoral lysis created some erosion and thinning of the medial calcar, as well as the superior acetabulum in the periphery. During revision, the acetabular shell was retained while the liner and the femoral stem were replaced with a revision stem ceramic head, and a highly crosslinked polyethylene liner. His post-operative course was uneventful and he has returned to his usual activities including playing golf 4–5 times a week at 5 months follow-up. Case 2 A 60 year-old man, who had a BMI of 30 kg/m 2, underwent a left primary cementless total hip arthroplasty in July of 2007 for a preoperative diagnosis of primary osteoarthritis. His past medical history included well-controlled hypertension. The femoral implant used was a standard offset cementless Accolade TMZF tapered wedge stem (Stryker Orthopaedics, Mahwah, New Jersey), while the acetabular component used during the index procedure was a cementless Trident PSL acetabular cup (Stryker Orthopaedics, Mahwah, New Jersey) of size 60 millimeters. The femoral head component was a 40 millimeters cobalt-chromium standard non-skirted head with a + 4 millimeters neck length on a V40 taper. The liner used was an X3 highly crosslinked polyethylene bearing (Stryker Orthopaedics, Mahwah, New Jersey). Immediate post-operative radiographs showed that the components were in satisfactory position with an acetabular angle of 45 degrees and an anteversion angle of 12 degrees. His post-operative course was uneventful and he had returned to his usual activities by 4 months. However, 7 years later, he presented to the office complaining of marked acute onset of left hip pain, instability, and clicking while getting off a toilet seat. He had a severe antalgic gait thereafter and

Please cite this article as: Banerjee S, et al, Gross Trunnion Failure After Primary Total Hip Arthroplasty, J Arthroplasty (2014), http://dx.doi.org/ 10.1016/j.arth.2014.11.023

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Fig. 2. (A) and (B) Initial radiographic images on presentation (patient 2) showing dissociation of the trunnion from the femoral head.

presented to the office for further evaluation. Radiographs revealed disassociation of the trunnion from the femoral head component (See Fig. 2A and B). The patient subsequently underwent revision surgery. Intra-operatively, the trunnion was found to be severely eroded and had the appearance of a ‘bird beak’ with corrosion of the anterosuperior and postero-superior surface and loss of volume of N50% (See Fig. 3A, 3B, and 4). In addition, severe local metallosis was found in the periprosthetic tissues with a mass of adverse local tissue reaction that perforated the abductor tendon. However, there was no evidence of osteolysis in the femur or the acetabulum. He underwent a revision of the femoral component and the liner and the post-operative course following revision were uneventful. Currently, he has returned to his usual activities at a follow-up of 5 months. Case 3 An 80 year-old man, who had a BMI of 30 kg/m2 underwent a right primary cementless total hip arthroplasty in December of 2002 for a pre-operative diagnosis of primary osteoarthritis. His past medical history included deep vein thrombosis, pulmonary embolism, hypothyroidism, and depression. The femoral implant used was a cementless size 14 Bimetric stem (Biomet Orthopaedics, Warsaw, Indiana), while the acetabular component used during the index procedure was a cementless Avantage Acetabular system (Biomet Orthopaedics, Warsaw, Indiana) of size 58 millimeters. The femoral head component was a 32 millimeters cobalt-chromium non-skirted head with a +4 millimeters neck length. The liner used was an ArCom (Biomet Orthopaedics, Warsaw, Indiana) UHMWPE polyethylene bearing. Immediate postoperative radiographs showed that the components were in satisfactory position and his immediate post-operative course was uneventful and he had returned to his usual activities. However, he sustained recurrent prosthetic hip dislocations in the post-operative period which were treated with closed reductions under anesthesia. Subsequently, in

Fig. 3. (A) Intra-operative images showing marked metallosis and gross deformity with bird beak appearance of the trunnion. (patient 2). (B) Debridement of large amounts of necrotic inflammatory tissue from the periprosthetic region (patient 2).

January of 2004, he underwent revision THA. The acetabular shell and the liner were revised to a 58 millimeters Trilogy socket (Zimmer Orthopaedics, Warsaw Indiana) and a posterior elevated liner. The femoral head was changed to a 32 millimeters diameter cobalt-chrome head with a +6 millimeters offset. The stem was retained as it was found to be well-fixed. After this revision, he returned to his full activities without any pain. However, 8 years later, he presented to the office complaining of the gradual onset, marked non-radiating left hip and groin pain. Radiographs revealed an asymmetric location of the trunnion on the femoral

Fig. 4. Typical bird beak appearance of the trunnion as a result of severe mechanically assisted crevice corrosion. (patient 2).

Please cite this article as: Banerjee S, et al, Gross Trunnion Failure After Primary Total Hip Arthroplasty, J Arthroplasty (2014), http://dx.doi.org/ 10.1016/j.arth.2014.11.023

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head component (See Fig. 5). The patient subsequently underwent exploration and revision surgery. Intra-operatively, the trunnion was found to be malformed with loss of volume of b 50% of the anterosuperior and postero-superior surface. Black debris suggestive of metallosis was found in the intra-capsular and peri-capsular tissues, and in the acetabular bone. A 10 centimeter grayish-colored mass was found surrounding the acetabulum. In addition there was evidence of minimal osteolysis in the proximal femur. However, no osteolysis was found in the peri-acetabular tissues. Extensive débridement of the black stained tissues and synovectomy was performed. The acetabular shell was retained while the liner and the femoral stem were replaced. His post-operative course was uneventful and he has returned to his usual daily activities at present follow-up of 16 months. Case 4 A 36 year-old man, who had a BMI of 47 kg/m 2 underwent a right primary cemented total hip arthroplasty in January of 1995 for a preoperative diagnosis of osteonecrosis. His past medical history included diabetes mellitus, atrial fibrillation, hyperlipidemia, cardiomyopathy, congestive heart failure, and deep venous thrombosis. The femoral implant used was a cemented size 10 RMHS Smith and Nephew Richards (Smith and Nephew Richards, Memphis, Tennessee), while the acetabular component used during the index procedure was a cementless Smith and Nephew Richards Reflection (Smith and Nephew Richards, Memphis, Tennessee) of size 54 millimeters. The femoral head component was a 28 millimeters ceramic head with a + 8 millimeters neck length, and a +12 mm Matrix taper sleeve. The liner used was a size F Reflection (Smith and Nephew Richards, Memphis, Tennessee) polyethylene bearing. Immediate post-operative radiographs showed that the components were in satisfactory position and his post-operative course was uneventful and he had returned to his usual activities. Subsequently, nineteen years later in January of 2014, he was bending over and felt a sudden snap in the hip. Radiographs demonstrated a fractured prosthesis at the stem trunnion (base of the skirted sleeve; See Fig. 6). He underwent revision right total hip replacement of all components. Intra-operatively the surgeon noted that the there was extensive blackened tissue suggesting that he had some type of metal debris reaction in his hip prior to the breakage. The joint was extensively debrided to remove all metal stained tissue. There were some signs of osteolysis

Fig. 5. Initial radiographic images on presentation show eccentric femoral head on trunnion due to failure (patient 3).

Fig. 6. Initial radiographic images on presentation showing fracture of the trunnion (patient 4).

around the acetabular component, however the femoral component remained well-fixed. An extended trochanteric osteotomy was performed, and the patient underwent revision with a modular cone conical femoral stem, as well as an acetabular component polyethylene liner replacement. At 1 year follow-up, the patient is doing well, and is able to perform activities of daily living without pain. Case 5 A 47-year old woman, who had a BMI of 23 kg/m2 at the time of left hip revision in February of 2011, underwent index cementless left total hip arthroplasty in November of 2003 for complaints of pain for many years due to degenerative osteoarthritis of the hip. The patient suffered from numerous comorbidities including spina bifida since birth, a childhood Sharrard procedure of the right hip (transposition illopsoas through iliac wing hole) causing some calcifications around the right hip with stiffness, diabetes mellitus, malignant hypertension with severe peripheral vascular calcifications, and pulmonary cystic fibrosis with severe limitation of lung capacity in recent years and a renal transplantation in 1998. The femoral implant used was a cementless Alloclassic Zweymuller (Sulzer), while the acetabular component used during the index procedure was a size 52 cementless Morscher (Sulzer). The femoral head component was a 32 millimeters alumina ceramic head, with a polyethylene bearing liner. The patient started developing progressive pain in early 2010; so much that even though she was multiple handicapped with quite limited activity levels; a request was made for revision surgery even though the exact cause of her progressive pain was not quite clear. An infection work-up prior to revision was negative (ESR/CRP were both low and technecium bone scan with low uptake) although joint aspiration for culture did not obtain fluid due to severe heterotopic calcification (Brooker grade IV). Metal ion analysis for titanium showed elevated levels (titanium alloy stem) of 14 μg/L (ref max 3 μg/L for patients with titanium implants without pathology, without implants 1 μg/L. max). Cobalt and chrome levels were not indicated due to an alumina ceramic bearing with polyethylene plus a titanium stem. Radiographs prior to revision demonstrated that there was severe heterotopic ossification with some osteolysis around the femoral head area. (See Fig. 7) Also, within the joint there were calcifications, which together with the progressive severe pain and elevated systemic

Please cite this article as: Banerjee S, et al, Gross Trunnion Failure After Primary Total Hip Arthroplasty, J Arthroplasty (2014), http://dx.doi.org/ 10.1016/j.arth.2014.11.023

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seen 12-months post revision when the hip was pain free although mobility still was limited, but better than prior to her revision surgery. Summation of Variables We found there to be no commonality in factors between all the 5 cases demographic, operative, and implant factors. However if you exclude the one female patient who had spina bifida, there were 4 male patients, all who had extended length femoral heads of +4 or greater femoral heads. (Please refer to Tables 1–3 for full details of factors) Discussion

Fig. 7. Initial radiographic images on presentation demonstrating heterotropic ossification. (patient 5).

titanium levels might suggest a problem in the trunnion or bearing area (See Fig. 8). The poor medical condition of the patient was prohibitive for extensive revision surgery such as cup/stem revision, but a limited exploration with removal of heterotopic bone and inspection of the taper junction was agreed upon with the anesthesiologist as an acceptable intervention. After removal of the heterotopic bone mass, the hip could be dislocated but the alumina ceramic femoral head remained in the acetabulum through a completely loose taper connection. The most proximal taper end was rounded off with black staining of the calcified mass nearby. Both stem and cup were found stable in the bone and thus were left in situ. Although there was taper damage, given the poor medical condition of the patient, it was decided to put a new femoral metal head with skirt in place so as to provide as large a possible contact area over the damaged trunnion. Patient was last

Fig. 8. Intra-operative image of trunnion with wear on superior and posterior portion (patient 5).

Apart from bearing surface wear, in the past few years, there has been an increasing concern about the production of metal ions and the occurrence of adverse local tissue reactions from fretting and corrosion at the head-neck taper junction in large diameter femoral heads in metal-on-metal total hip arthroplasties. However, historically, conical tapers have enjoyed an excellent track record in metal-on-polyethylene and ceramic-on-polyethylene bearings in total hip arthroplasties. Nevertheless, in the recent past, there have been a limited number of studies that have reported on the occurrence of adverse tissue reactions, similar to those seen in patients with metal-on-metal arthroplasty implants, secondary to potential fretting and corrosion at the modular femoralhead neck taper junction in non-metal-on-metal bearings [6,7,11]. Fretting wear and corrosion have been reported with single and double taper stem designs from a variety of manufacturers. Despite these reports, there has been a paucity of studies that have comprehensively evaluated the mechanical consequences of a new type of taper junction failure. In this report, we have attempted to describe the various patient-, surgical-, and radiographic factors that may have potentially contributed to the development of these gross trunnion failures. A variety of patient- and surgical factors such as comorbidities, presence of heterotopic ossification, skirted necks, neck lengths, trunnion types, and femoral had sizes were found in patients who had trunnion failures. However, we did not find a common link among the trunnion failures and although speculatory, a combination of the above factors, including taper damage during insertion, tissue interposition, failure to achieve initial engagement, taper malpositioning, or variations in head-neck association strength from different impaction techniques, may have been responsible. This report has several limitations. This is a retrospective evaluation involving a small number of patients from multiple institutions. We could not determine the incidence of these complications, and it may be likely that some other cases from the institutions may have been missed. Also, we did not perform stereo-microscopic analysis of the retrieved failed implants for evaluation of surface topographic alterations suggestive of manufacturing inconsistencies which might have predicted any implant-related factor that may have been responsible for these failures. Moreover, not all cases had metal ion levels measured or cross-sectional imaging performed pre-operatively. One should note that there has been an increased focus on the taperjunction of modular hip arthroplasties due to recent reports of trunnionosis with metal-on-polyethylene bearings. Cooper and coauthors [7] in a study of 10 patients with metal-on-polyethylene arthroplasties from 3 implant manufacturers, initially reported on the occurrence of corrosion at the modular head-neck junction with elevation of the metal ions (Co N Cr) and formation of adverse periprosthetic soft tissue reactions. More recently, Jacobs et al [6], in a report of 20 patients who had undergone metal-on-polyethylene arthroplasties found mechanically assisted crevice corrosion occurring at the taper junction at a mean follow-up of 3.9 years (range, 0.7–17.3 years). The authors found that these corrosive reactions occurred with a variety of taper designs, head sizes, as well as the metal composition of the head-neck junction.

Please cite this article as: Banerjee S, et al, Gross Trunnion Failure After Primary Total Hip Arthroplasty, J Arthroplasty (2014), http://dx.doi.org/ 10.1016/j.arth.2014.11.023

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Table 1 Demographic and Presenting Features. Manufacturing Company/ Implant Name

Age at Weight BMI Index (Kg) (Kg/ Surgery/ m2) Gender

Patient Number 1.

Zimmer; ML taper Stryker, Accolade TMFZ Biomet; Taperloc Smith and Nephew Richards Sulzer, Alloclassic Zweymuller

2.

3. 4.

5.

40

FollowUp Prior to Revision THA (years)

FollowUp After Revision Surgery (months)

Presenting Symptoms

7.9

4

Groin pain

Obesity

Primary OA

6.7

2

Groin pain, instability clicking

HTN

Primary OA

DVT, PE, hypothyroidism, Primary OA depression DM, Afib, hyperlipidemia, Primary OA CHF, DVT,

Comorbidities Preoperative Diagnosis

67/M

126

60/M

88

80/M

97

30

8.4

16

Groin pain

36/M

81

47

19

12

Groin pain, snap in hip

39/W

61

23

7.3

26

Groin pain and stiffness

Renal transplant, cystic lung fibrosis, DM,HTN, spina bifida

Primary OA

Groin pain; inability to bear weight Groin pain; inability to bear weight Groin pain; inability to bear weight; instability Groin pain; crepitus;

NA

Primary OA

NA

Primary OA

NA

Primary OA

NA

Primary OA

Literature Review 1.

Unnanuntana et al Depuy; AML-A *

48/M

72

25

6

12

2.

Unnanuntana et al Depuy; AML-A *

59/M

104

32

7

3

3.

Botti et al

Depuy; AML

70/M

90

27.2 8

3

4.

Hohman et al

Stryker, Accolade 64/F TMFZ;

70

NA

NA

4

OA: osteoarthritis; HTN: hypertension; DM: diabetes mellitus: M: man; W: woman; MI: myocardial infarction; CABG: coronary artery bypass graft; CRF: chronic renal failure; ESRD: end stage renal disease; Afib: atrial fibrillation; AS: aortic stenosis;* Unnanuntana et al; DVT: deep vein thrombosis; PE: pulmonary embolism; GERD: gastro esophageal reflux disease; CHF: congestive heart failure.

However, the gross trunnion failures in the present report appear different from the black stained trunnions reported by Jacobs et al [6] and others, and probably occur due to a different mechanism. There have been only a few case studies reported on gross trunnion failures or fractures causing disassembly of the femoral head component or marked trunnion material loss [4,9,12–14]. In addition to these case reports, there have been a number of cases of potential gross trunnion failures (e.g. trunnion fractures) reported in the Food and Drug Administration-Manufacturer and User Facility Device Experience database (FDA-MAUDE) with various stem designs from multiple manufacturers. A FDA-MAUDE search for these type of failure demonstrated that there were less than 45 cases involving 5 manufacturers over the last 4 and half years and provides emphasis that this appears to be a generic problem involving multiple manufactures, which is presently rarely reported. However, the cases submitted to the Food and Drug Administration (FDA) are reported by a variety of mandatory reporters such as manufacturers, importers, device user facilities, and other voluntary sources (for e.g. healthcare professionals, patients, and consumers). Although many of these reports are under investigation by the manufacturers and the federal agency, and a comprehensive analysis is not currently possible due to a lack of adequate publicly available data, it highlights some of the potential concerns with modern taper designs. Concerning the few known prior published case reports on gross trunnion failures, Botti et al [9] reported a case of a fracture within the Morse taper without any history of antecedent trauma, 15 years following implantation of an AML stem (Depuy Orthopaedics Inc. Warsaw, Indiana). The authors speculated that a variety of factors may have been responsible for its development, including fretting corrosion from abnormal interface motion, use of a skirted femoral neck on a thin neck diameter causing reduced flexural rigidity, and scratching and pitting of the femoral neck during insertion. Unnanuntana et al [14] reported on 2 cases of atraumatic trunnion fractures from excessive wear of small trunnion design (9/10) in an AML-A prostheses (Depuy

Orthopaedics Inc. Warsaw, Indiana). The authors also believed that deep grooves present on the trunnion surface and intergranular corrosion may have additionally contributed to this complication. Various implant-related factors including mismatch of head-neck taper, taper malpositioning, and mixed-alloy head-trunnion couples have been postulated as potential causes for gross failures at the headneck taper junction [2–5]. Hohman et al [4] reported on the occurrence of marked fretting wear with substantial loss of volume of the beta titanium taper following mismatch of an alumina C-taper head on the trunnion in a 64 year old woman at a follow-up of 3 years. The authors believed that the altered surface area of contact led to rapid deformation and wear of the trunnion. Stokes [15], in a questionnaire study conducted on members of the New Zealand Orthopaedic Association, evaluated the frequency of mismatch components selected during total hip arthroplasties. It was found that approximately 80 surgeons (23%) had implanted mismatched components during a 5-year period. The mismatch was identified before wound closure in 39%, during the admission in 51% and after discharge in another 10%. A further surgical procedure was necessitated in 13 patients (46%) [15]. Although we did not find any case of mismatch of components or taper malposition in our series, this may be a source of potential concern as the incidence may be higher than recognized as some of the mismatches are initially clinically silent. Currently, we believe that there is no clear evidence to suggest that a discrete variable, be it patient, surgical, or implant-related, to be ultimately responsible for the development of gross trunnion failures. These factors may tend to point toward commonality; however, we believe that our report suggests that a combination of factors potentially contributed to these catastrophic trunnion failures. However, if the one female patient who had spina bifida is excluded (which is known to cause proprioceptive disruption at the hip in many cases and altered biomechanics and hip loading), you have 4 male patients, all with extended length femoral heads of + 4 or greater femoral heads, which

Please cite this article as: Banerjee S, et al, Gross Trunnion Failure After Primary Total Hip Arthroplasty, J Arthroplasty (2014), http://dx.doi.org/ 10.1016/j.arth.2014.11.023

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Table 2 Radiographic Details, Surgical Data.

Patient Number

Femoral Head Material

1.

Co-Cr

Ti-Al6-V4 alloy

Yes

Yes

2.

Co-Cr

No

No

3.

Co-Cr

Betatitanium alloy Ti-Al6-V4 alloy

Yes

Yes

4.

Ceramic

Yes

Yes

5.

Ceramic

Ti-Al6-V4 alloy Ti6-Al7-Nb4 alloy

No

No

Literature Review

Femoral Taper Material

Extended Skirted Offset Head

Head Size, Neck Length; Taper Size

Liner

Acetabular Inclination and Anteversion

Coronal Femoral Alignment and Intraoperative Femoral Anteversion

Change in Vertical and Horizontal Offset

Osteolysis

32 mm; +4 mm; 12/14 40 mm; +4 mm; V40 32 mm; +6 mm; 12/14 28 mm; +12 mm; 12/14 32 mm; 0 mm; 12/14

Highly X- 45°/20° linked UHMWPE Highly X- 45°/10° linked UHMWPE UHMWPE NA

Neutral/10°

NA

Yes ¥

Neutral/10°

4 and 0 mm

No

NA

NA

No

UHMWPE 43°

NA

No

Yes

UHMWPE 44°/16°

5° varus/18°

0/0 mm

No

28 mm; +6 mm; 9/10 28 mm; +6 mm; 9/10 28 mm; +12 32 mm

UHMWPE NA

NA

NA

NA

UHMWPE NA

NA

NA

NA

UHMWPE NA Ceramic NA

NA NA

NA NA

NA NA

Authors

1.

Unnanuntana Co-Cr et al

Yes

Yes

2.

Unnanuntana Co-Cr et al

Yes

Yes

3. 4.

Botti et al Co-Cr Hohman et al Ceramic

No No

Yes No

Betatitanium alloy

CoP: ceramic-on-polyethylene; Co-Cr: cobalt chromium; MoP: metal-on-polyethylene; mm: millimeters; ¥ - proximal femoral and peripheral acetabular lysis.

biomechanically may lead to increased stresses that result in prosthesis fatigue and failure. Due to extensive metal débris and corrosion seen at the trunnion in a majority of the case, we do not believe this is simple fretting and crevice corrosion, and speculate that these increased stress may have resulted in increased motion between the trunnion and head, leading to higher degree of catastrophic wear and corrosion. In addition, the one female patient had a ceramic head, which might lead to decreased motion of the femoral head and increased motion at the trunnion due to phase changes. Ceramic femoral head have been shown to undergo a phase change which results in increased volume, and

subsequently increased volumetric wear. However, it is conceivable that the ceramic head increases in volume causing engagement into the liner which produces increased motion at the at the head trunnion junction. We may conclude that there are no data to implicate that the taper or neck geometries of particular prosthetic designs are associated with gross trunnion failures. It is currently not possible to truly estimate the incidence of these trunnion failures due to their infrequent occurrence, however the fact that there were 5 different stem designs involved suggests that this may be a generic phenomenon that is rare.

Table 3 Intra-Operative Details and Complications.

Patient Number

Manufacturing Company/ Implant Name

1.

Zimmer; ML taper

2.

Stryker, Accolade TMFZ Biomet; Bimetric Hip system Smith and Nephew Richards Sulzer, Alloclassic Zweymuller

3. 4. 5.

Pseudotumor/Metallosis/ ALTRs/Others

Metal Ion Levels

Complications (Post-Operative)

Potential In Vivo Mechanisms

Black debris suggestive of metallosis 4X4 cm; Severe metallosis; perforation of abductor tendon Severe metallosis; 10 cm mass surrounding the acetabulum Blacked stained tissue

Co:0.5 μg/L; Cr: 2.9 μg/L NA

Greater trochanter #

Obesity: N=no discernible cause

None

No discernible cause

NA

None

Multiple factors; no discernible cause

NA

None

No discernible cause

Severe metallosis

Ti: 14 μg/L (ref max 3 μg/L

None

Heterotopic ossification may have augmented the outcome; no discernible cause

Literature Review

Author

1.

Unnanuntana et al

Depuy; AML-A *

NA

NA

None

2.

Unnanuntana et al

Depuy; AML-A *

NA

NA

None

3.

Botti et al

Depuy; AML**

NA

None

Hohman et al

Stryker, Accolade TMFZ

Metallosis in the proximal 1/3 of the femur Metallosis

Multiple factors; small trunnion; machining grooves Multiple factors; small trunnion; machining grooves Intergranular and crevice corrosion

NA

None

Mismatch of the head on taper

4. #

: Fracture; NA: not available; Ti: titanium; Co: cobalt; Cr: chromium.

Please cite this article as: Banerjee S, et al, Gross Trunnion Failure After Primary Total Hip Arthroplasty, J Arthroplasty (2014), http://dx.doi.org/ 10.1016/j.arth.2014.11.023

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S. Banerjee et al. / The Journal of Arthroplasty xxx (2014) xxx–xxx

Furthermore, we feel that it is imperative that multi-center collaborative clinical and implant retrieval studies are necessary for the better understanding and evaluation of these unprecedented outcomes and reducing taper-related complications. Nevertheless, many of these stem designs reported in this study have enjoyed excellent survivorship at long-term (N 10 year) follow-up and the present series only reports a few cases that have had untoward outcomes. Furthermore, continued research on taper design including clearance angles, taper thickness, and surface topographies is needed to minimize concerns about headneck taper corrosion in metal-on-polyethylene and ceramic-onpolyethylene bearings.

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4. Hohman DW, Affonso J, Anders M. Ceramic-on-ceramic failure secondary to headneck taper mismatch. Am J Orthop (Belle Mead NJ) 2011;40(11):571. 5. Pansard E, Fouilleron N, Dereudre G, et al. Severe corrosion after malpositioning of a metallic head over the Morse taper of a cementless hip arthroplasty. A case report. Orthop Traumatol Surg Res 2012;98(2):247. 6. Jacobs JJ, Cooper HJ, Urban RM, et al. What do we know about taper corrosion in total hip arthroplasty? J Arthroplasty 2014;29(4):668. 7. Cooper HJ, Della Valle CJ, Berger RA, et al. Corrosion at the head-neck taper as a cause for adverse local tissue reactions after total hip arthroplasty. J Bone Joint Surg Am 2012;94(18):1655. 8. Vundelinckx BJ, Verhelst LA, De Schepper J. Taper corrosion in modular hip prostheses: analysis of serum metal ions in 19 patients. J Arthroplasty 2013;28(7):1218. 9. Botti TP, Gent J, Martell JM, et al. Trunion fracture of a fully porous-coated femoral stem. Case report. J Arthroplasty 2005;20(7):943. 10. Pradhan R. Planar anteversion of the acetabular cup as determined from plain anteroposterior radiographs. J Bone Joint Surg Br 1999;81(3):431. 11. Bisseling P, Tan T, Lu Z, et al. The absence of a metal-on-metal bearing does not preclude the formation of a destructive pseudotumor in the hip–a case report. Acta Orthop 2013;84(4):437. 12. Lee EW, Kim HT. Early fatigue failures of cemented, forged, cobalt-chromium femoral stems at the neck-shoulder junction. J Arthroplasty 2001;16(2):236. 13. Gilbert JL, Buckley CA, Jacobs JJ, et al. Intergranular corrosion-fatigue failure of cobaltalloy femoral stems. A failure analysis of two implants. J Bone Joint Surg Am 1994;76 (1):110. 14. Unnanuntana A, Chen DX, Wright TM. Trunnion fracture of the anatomic medullary locking a plus femoral component. J Arthroplasty 2011;26(3):504 e13. 15. Stokes AP, Rutherford AD. Mistmatch of modular prosthetic components in total joint arthroplasty. The New Zealand Experience. J Bone Joint Surg Br 2005;87-B(no. SUPP I 32).

Please cite this article as: Banerjee S, et al, Gross Trunnion Failure After Primary Total Hip Arthroplasty, J Arthroplasty (2014), http://dx.doi.org/ 10.1016/j.arth.2014.11.023