Prosthetic Head Research Articles

Restoration of the Hip Center During THA Performed for Protrusio Acetabuli Is Associated With Better Implant Survival

Acetabular protrusio is an uncommon finding in hip arthritis. Several reconstructive approaches have been used; however the best approach remains undefined. Our purposes in this study were to (1) describe the THA survivorship for protrusio as a function of the acetabular component, (2) evaluate survivorship of the cup as a function of restoration of radiographic hip mechanics and offset, and (3) report the long-term clinical results. One hundred twenty-seven patients (162 hips) undergoing primary THA with acetabular protrusio were retrospectively reviewed. The mean age of the patients at surgery was 66±13 years, and the mean followup was 10±6 years (range, 2-25 years).The cup fixation was uncemented in 107 (83 with bone graft) and cemented in 55 hips (14 with bone graft). Preoperative and postoperative radiographs were reviewed for restoration of hip mechanics and offset. The THA survival from aseptic cup revision at 15 years was 89% (95% CI, 75%-96%) for uncemented compared with 85% (95% CI, 68%-94%) for cemented cups. The risk of aseptic cup revision significantly increased by 24% (hazards ratio, 1.24; 95% CI, 1.02-1.5) for every 1 mm medial or lateral distance away from the native hip center of rotation to the prosthetic head center. Harris hip scores were improved by mean of 27±20 points (n=123) with a higher postoperative score for uncemented bone grafted compared with solely cemented cups (81±16 versus 71±20 points). Restoring hip center of rotation using an uncemented cup with or without bone graft was associated with increased durability in our series. There was a 24% increase in the risk of aseptic cup revision for every 1 mm medial or lateral distance away from the native hip center to the prosthetic head center. Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

The effects of prosthetic humeral head shape on glenohumeral joint kinematics: a comparison of non-spherical and spherical prosthetic heads to the native humeral head

The purpose of this study was to quantitatively evaluate the effect of the prosthetic humeral head shape on rotational range of motion and glenohumeral joint kinematics. Six fresh-frozen cadaveric shoulders were tested in multiple positions under anatomic muscle loading. Specimens were tested for the native head, and then the spherical and non-spherical prosthetic heads were randomly implanted in the same stem to preserve the center of rotation. Rotational range of motion was measured with 3.3 Nm of torque. Glenohumeral joint kinematics was quantified by the position vectors of the humeral head apex (HHA) and geometric center of the humeral head (GCHH) to calculate translation of HHA and GCHH per degree of humeral rotation. The non-spherical prosthetic head replicated the native head shape more accurately than the spherical prosthetic head. Between the non-spherical and native heads, there was no statistical difference in rotational range of motion (P>.05), but a statistical difference in HHA and GCHH translation was found at 60° of scapular plane abduction in the interval from 30° of internal rotation to neutral rotation and at 30° of forward flexion plane abduction in the interval from 30° of external rotation to maximum external rotation, respectively (P<.05). The spherical head significantly decreased rotational range of motion (P<.05), increased HHA translation per degree (P<.05), and decreased GCHH translation per degree (P<.05) in multiple positions compared with the native humeral head. The custom, non-spherical prosthetic head more accurately replicated the head shape, rotational range of motion, and glenohumeral joint kinematics than the commercially available, spherical prosthetic head compared with the native humeral head.

The influence of head diameter and wall thickness on deformations of metallic acetabular press-fit cups and UHMWPE liners: a finite element analysis

BackgroundTo increase the range of motion of total hip endoprostheses, prosthetic heads need to be enlarged, which implies that the cup and/or liner thickness must decrease. This may have negative effects on the wear rate, because the acetabular cups and liners could deform during press-fit implantation and hip joint loading. We compared the metal cup and polyethylene liner deformations that occurred when different wall thicknesses were used in order to evaluate the resulting changes in the clearance of the articulating region. MethodsA parametric finite element model utilized three cup and liner wall thicknesses to analyze cup and liner deformations after press-fit implantation into the pelvic bone. The resultant hip joint force during heel strike was applied while the femur was fixed, accounting for physiological muscle forces. The deformation behavior of the liner under joint loading was therefore assessed as a function of the head diameter and the resulting clearance. ResultsPress-fit implantation showed diametral cup deformations of 0.096, 0.034, and 0.014mm for cup wall thicknesses of 3, 5, and 7mm, respectively. The largest deformations (average 0.084±0.003mm) of liners with thicknesses of 4, 6, and 8mm occurred with the smallest cup wall thickness (3mm). The smallest liner deformation (0.011mm) was obtained with largest cup and liner wall thicknesses. Under joint loading, liner deformations in thin-walled acetabular cups (3mm) reduced the initial clearance by about 50%. ConclusionAcetabular press-fit cups with wall thicknesses of ≤5mm should only be used in combination with polyethylene liners >6mm thick in order to minimize the reduction in clearance.

Wear analysis of a ceramic on ceramic hip endoprosthesis

The authors have analyzed the wear of a ceramic-on-ceramic hip joint prosthesis retrieved after 25 years of use. Severe wear and flattening of the femoral head was revealed, while the acetabular component was less worn. Three wear zones can be seen on the femoral head depending on surface topography. The wear patterns of the ceramic components of the prosthetic head indicate the role of microseparation that occurs during implant functioning.

The removal of acetabular bone in hip resurfacing and cementless total hip replacement

The purpose of this study was to compare the amount of acetabular bone removed during hip resurfacing (HR) and cementless total hip replacement (THR), after controlling for the diameter of the patient's native femoral head. Based on a power analysis, 64 consecutive patients (68 hips) undergoing HR or THR were prospectively enrolled in the study. The following data were recorded intra-operatively: the diameter of the native femoral head, the largest reamer used, the final size of the acetabular component, the size of the prosthetic femoral head and whether a decision was made to increase the size of the acetabular component in order to accommodate a larger prosthetic femoral head. Results were compared using two-sided, independent samples Student's t-tests. A statistically significant difference was seen in the mean ratio of the size of the acetabular component to the diameter of the native femoral head (HR: 1.05 (SD 0.04) versus THR: 1.09 (SD 0.05); p < 0.001) and largest acetabular reamer used to the diameter of the native femoral head (HR: 1.03 (SD 0.04) versus THR: 1.09 (SD 0.05); p < 0.001). The ratios varied minimally when the groups were subdivided by gender, age and obesity. The decision to increase the size of the acetabular component to accommodate a larger femoral head occurred more often in the THR group (27% versus 9%). Despite the emphasis on avoiding damage to the femoral neck during HR, the ratio of the size of the acetabular component to the diameter of the native femoral head was larger in cementless THR than in HR.

EFFECT OF GLENOID IMPLANT DESIGN ON GLENOHUMERAL STABILITY: AN EXPERIMENTAL STUDY

Abstract Background Though several glenoid implants were developed over the past years, a high rate of glenoid loosening remains. This complication is linked to the glenohumeral stability, defined as humeral head translation. In an intact shoulder, this concept is ensured by all active and passive elements, particularly the labrum. Two features of a glenoid implant can be adjusted to improve the stability, or, in other words, to decrease the translations: the first is the mismatch, defined as the difference of curvature between the prosthetic head and glenoid; the second is the shape of the glenoid component. Therefore, the objective of this study was to compare the performance of 2 glenoid components (Ceraver, Roissy, France): (1) a standard design and (2) a design named “labrum design” with a superior part simulating the anatomic labrum. Methods An experimental device was developed to evaluate forces and kinematics. The device simulated active, dynamic and continuous abduction of an entire arm. It reproduced the Scapulo-Humeral Rhythm. The labrum design was installed first. To evaluate the effect of mismatch on the glenohumeral stability, 3 humeral heads were tested, corresponding to the ones recommended by the company. The experiment was repeated for the standard design. Findings The results obtained show a general decrease of the prosthetic head translation with the labrum design compared to the standard design. No noticeable effect of mismatch was found. Interpretation A proof of concept of the interest of the artificial labrum was provided since it improved the glenohumeral stability.

Effect of glenoid implant design on glenohumeral stability: An experimental study

BackgroundThough several glenoid implants were developed over the past years, a high rate of glenoid loosening remains. This complication is linked to the glenohumeral stability, defined as humeral head translation. In an intact shoulder, this concept is ensured by all active and passive elements, particularly the labrum. Two features of a glenoid implant can be adjusted to improve the stability, or, in other words, to decrease the translations: the first is the mismatch, defined as the difference of curvature between the prosthetic head and glenoid; the second is the shape of the glenoid component. Therefore, the objective of this study was to compare the performance of 2 glenoid components (Ceraver, Roissy, France): (1) a standard design and (2) a design named “labrum design” with a superior part simulating the anatomic labrum. MethodsAn experimental device was developed to evaluate forces and kinematics. The device simulated active, dynamic and continuous abduction of an entire arm. It reproduced the Scapulo-Humeral Rhythm. The labrum design was installed first. To evaluate the effect of mismatch on the glenohumeral stability, 3 humeral heads were tested, corresponding to the ones recommended by the company. The experiment was repeated for the standard design. FindingsThe results obtained show a general decrease of the prosthetic head translation with the labrum design compared to the standard design. No noticeable effect of mismatch was found. InterpretationA proof of concept of the interest of the artificial labrum was provided since it improved the glenohumeral stability.

Humeral head arthroplasty and its ability to restore original humeral head geometry

Modern prosthetic components are designed to enable restoration of proximal humeral morphology, provided that a precise osteotomy of the humeral head at the level of the anatomic neck is performed. To determine whether a simulated osteotomy and replacement arthroplasty with an idealized implant were able to restore original head geometry. A handheld digitizer and surface laser scanner were used to digitize 24 humeri. Computer models were used to simulate an osteotomy, performed at the anterior cartilage-metaphyseal interface, and reconstruct the head with a spherical prosthetic head. The head diameter, radius of curvature, and inclination and retroversion angles were calculated for each specimen and compared with the original humeral head. The simulated osteotomy resulted in a 4.8° decrease in inclination (P<.01) and 11.3° increase in retroversion (P<.001). The radius of curvature in the coronal plane was not significantly different (P=.284). However, in the axial plane, the prosthesis was significantly larger than the original head for both head diameter (P<.001) and radius of curvature (P<.05). The study suggests that the humeral head is not a perfect segment of a sphere and an osteotomy along the anterior cartilage-metaphyseal interface does not remove only the proximal humeral articular surface. Even with a fully adaptable prosthetic implant, replacement arthroplasty is not able to restore original head geometry. Alterations to head geometry with the osteotomy described may alter the line of force through the prosthetic joint, producing eccentric loading at the glenoid, and contribute to early failure.

The Surgical Anatomy of Intra-Abdominal Prosthetic Dislocation during Hip Arthroplasty

Hip replacement surgery remains one of the most successful and common operations in modern orthopaedics. Many surgical approaches to the hip have been described. A potential anatomical weakness exists between the hip joint and the retroperitoneal space. We describe this potential space, which lies superficial to iliopsoas and its importance in hip replacement surgery. The clinical relevance of this space is illustrated by 2 cases of retro-peritoneal migration of prosthetic femoral heads and the consequences of these.

Dual mobility canine total hip prosthesis: Implant characteristics and surgical procedure

Prosthetic dislocation is one of the most common complications after canine hip replacement. The use of dual mobility acetabular components has been shown to reduce the rate of dislocation in first intent hip replacement in human patients who are at high risk for dislocation. In such implants, a mobile polyethylene liner articulates on one side with a metallic acetabular component and on the other side with a metallic prosthetic head. A dual mobility cemented acetabular component has been designed for use in dogs, and is available for use in association with a previously designed modular femoral component. This report describes the characteristics and the procedure for implantation of this implant combination.

Radiostereometric analysis of hemiarthroplasties of the hip – a highly precise method for measurements of cartilage wear

Cartilage wear is a feature of osteoarthritis and rheumatoid arthritis. Precise measurements of wear have been difficult. Cartilage wear caused by an artificial articulating joint surface is a well-known feature of hemiarthroplasties. The aim of this study was to demonstrate that radiostereometric analysis (RSA) may be used for three-dimensional measurements of cartilage wear in hemiarthroplasties of the hip. We performed a phantom model study to assess the feasibility of a subsequent clinical trial. We showed that the motion of the prosthetic head relative to the pelvis was not influenced by the orientation of the prosthetic head. Twenty-two patients were randomised to treatment with a cemented or an uncemented hemiarthroplasty for an acute femoral neck fracture. Migration of the prosthetic head into the acetabulum was measured using RSA. A mean migration of the prosthetic head into the acetabulum of 0.62mm was found at 3months [95% confidence interval (CI): 0.27-0.97] and a further migration of-0.07mm at 12months (95% CI:-0.16-0.32). There were no differences between the groups in prosthetic migration or functional outcome. Between threeand 12months, there was no detectable cartilage wear during the first postoperative year. Whether the migration during the first 3months represents a period of bedding in due to a harder opposite surface remains to be shown. RSA may be used for measurement of cartilage wear in hemiarthroplasties of the hip. This study demonstrates a highly precise method for measurements of cartilage wear.

Sensualities/Textualities and Technologies: Writings of the Body in 21st-Century Performance (review)

Reviewed by: Sensualities/Textualities and Technologies: Writings of the Body in 21st-Century Performance Spencer Schaffner Sensualities/Textualities and Technologies: Writings of the Body in 21st-Century Performance. Edited by Susan Broadhurst and Josephine Machon. New York: Palgrave Macmillan, 2010; pp. 240. An increasing number of contemporary performance forms involve new technologies. Susan Broadhurst and Josephine Machon's edited collection Sensualities/Textualities and Technologies: Writings of the Body in 21st-Century Performance, explores this highly technological present in the world of performance, suggesting that new technologies are augmenting, not replacing, the body in an array of experimental works. This collection tracks an emerging dialogue in contemporary performance between bodies and what science fiction writers have termed "the machines." Serving as a guide to this emergent field, Broadhurst and Machon's book shows how technologically rich performance forms explore, comment on, and, in some cases, critique the computer-integrated age in which we live. The collection consists of fifteen chapters written by practitioners and critics alike, each of which suggests that, despite the expanding variety of technological options available to artists, the body maintains its centrality in most performance texts. Instead of understanding the body as distinct from technology, however, the contributors to the collection describe performing bodies as one of several technologies used in any given performance. Innovative contemporary artists and companies demonstrate, this collection argues, that bodies are technological, and, reciprocally, that technologies can be understood through embodied performance. Not surprisingly, interactivity is a recurring theme here. Readers interested in how contemporary artists implement interactive digital-media forms in performance will find Troika Ranch, the Critical Art Ensemble, and Bodies in Flight particularly thought-provoking for the ways they use live relay cameras, neurological imaging, and computer software as active participatory elements in their staged work. As Broadhurst describes in the book's grounding first chapter, the New York City dance company Troika Ranch relies just as much on instrument data-interface and Open Sound Control software as it does on its dancers. Machines, in a sense, are part of the company. Performing with digitized and manipulated projections of their own forms, the members of Troika Ranch create an iterative conversation of movement: dance creates projected images, which inspire more dance. Neither dancer nor computer has primacy in this relationship, as the two reproduce each other's movements onstage. This theme of interactivity extends beyond the relationship between embodied performer and machine to include the audience. Tracey Warr's chapter "Texts from the Body" deals with Bruce Gilchrist's installations involving neurological imaging. In her detailed study of Gilchrist's work, Warr shows how technologically mediated installations of the kind that Gilchrist creates—in one such work, the artist sleeps while gallery-goers attempt to interact with his brainwaves—cannot be reduced to simple claims about the ubiquity of computing or encroaching industrial consumer culture. Indeed, many of the contributors to this collection argue that technology is a complicated means of engaging the body as a somatic reservoir of emotion and feeling. Sensualities, as Broadhurst and Machon's title suggests, are not necessarily diminished in supposedly sterile technologized encounters with computers, but instead, in some cases, are intensified. [End Page 486] No treatment of contemporary performance would be complete without a nod to some of the best-known and most provocative artists of our time. Accordingly, John Freeman considers John Leguizamo's work, Josephine Machon analyzes the plays of Caryl Churchill, and Stelarc discusses his own interactive piece "Prosthetic Head." The latter is one of the highpoints of the collection, as Stelarc's three-dimensional, animated chat-bot (gallery-goers converse with the virtual head in real time) captures both the fear and the fantasy of robots as human surrogates. Broadhurst and Machon are careful to balance the number of chapters about individual artists with as many about artistic collectives, both to avoid endorsing the idea of the lone genius and to highlight the importance of collaboration in much contemporary innovative art. In this collection, innovation is frequently identified with the technique of remix (the recombination of previously released and published materials), which is often used as a distinct form of politicized social commentary. Consider, for example, the dance...

Adverse reaction to metal release from a modular metal-on-polyethylene hip prosthesis

A 70-year-old man with an uncemented metal-on-polyethylene total hip prosthesis underwent revision arthroplasty 33 months later because of pain, swelling and recurrent dislocation. There appeared to be corrosion and metal release from the prosthetic head, resulting in pseudotumour formation and severe local soft-tissue destruction. The corrosion occurred at the junction between the titanium-molybdenum-zirconium-iron taper and the cobalt-chrome-molybdenum head, but the mechanism was unproven.

Finite Element Modelling of Shock-Induced Damages on Ceramic Hip Prostheses

The aim of this work was to simulate the behaviour of hip prostheses under mechanical shocks. When hip joint is replaced by prosthesis, during the swing phase of the leg, a microseparation between the prosthetic head and the cup could occur. Two different sizes of femoral heads were studied: 28 and 32 mm diameter, made, respectively, in alumina and zirconia. The shock-induced stress was determined numerically using finite element analysis (FEA), Abaqus software. The influence of inclination, force, material, and microseparation was studied. In addition, an algorithm was developed from a probabilistic model, Todinov's approach, to predict lifetime of head and cup. Simulations showed maximum tensile stresses were reached on the cup's surfaces near to rim. The worst case was the cup-head mounted at 30°. All simulations and tests showed bulk zirconia had a greater resistance to shocks than bulk alumina. The probability of failure could be bigger than 0.9 when a porosity greater than 0.7% vol. is present in the material. Simulating results showed good agreement with experimental results. The tests and simulations are promising for predicting the lifetime of ceramic prostheses.

Severe Metallosis Owing to Intraprosthetic Dislocation in a Failed Dual-Mobility Cup Primary Total Hip Arthroplasty

We report a case of extensive metallosis owing to an intraprosthetic dislocation of a dual-mobility cup after a primary total hip arthroplasty. A 70-year-old man was referred to us from another center with a painful right hip 3 years after the arthroplasty. Initial investigations were suspicious of osteolysis secondary to metallosis with the characteristic “bubble sign” visualized on plain radiographs. At the revision procedure, widespread black staining of soft tissues and bone was noted. The polyethylene liner had dislodged leading to erosion of the metal socket by the prosthetic head. Histopathology examination of periprosthetic tissue confirmed metallosis. To our knowledge, this is the first reported case of severe metallosis owing to a known complication of dual-mobility sockets.

Should the Acetabular Cup be Medialised in Total Hip Arthroplasty?

During total hip arthroplasty (THA), medialisation of the cup decreases the lever arm of body weight and is considered to be beneficial. Theoretically it should be compensated by an equivalent increase of the femoral offset in order to maintain global offset. We investigated via a numerical model the forces on each bundle of the abductor muscles and the loading forces at the head-cup interface. We compared THA with and without medialisation of the cup and with and without restoration of the global offset. A digital finite element model of the hip joint with THA was constructed. Monopodal weightbearing was simulated with the cup positioned so that the hip centre of rotation was left unchanged. Forces in the abductors and pressure on the prosthetic head were measured and then compared with three other configurations: 1. Medialisation of the cup by 5 to 15 mm with reproduction of the native femoral offset or; 2. with an increased femoral offset compensating for the cup medialisation and; 3. no medialisation of the cup with a femoral offset increased. Medialisation of the cup decreased stresses on the head-cup interface and on the abductor muscles, even when the global offset was not restored. Anatomical placement of the cup did not give the best results. The optimal outcome in terms of stress was observed when the cup was medialised but global offset restored. Any increase of global offset significantly increases the length and the tension in the anterior bundles of the abductor muscles.

Functional results of hip arthroplasty with acrylic prosthesis

The results of 340 patients who underwent arthroplasty from 1948 – 1952 for trauma or osteoarthritis using an acrylic Judet prosthesis are reviewed. Early results (< 2 years) indicate the importance of restoration of the normal mechanics of the hip joint by the preservation or the restoration of normal length of the femoral neck, the exact correction of the anteversion, and the precise fit of the prosthetic head into the acetabulum. Late results show deterioration of the functional results in 20% of patients that appears to be caused by bone absorption around the Judet prosthesis and consequent loosening of the prosthesis. Use of a new type of cervicocapital prosthesis is proposed that aims to decrease the incidence and effects of bone absorption by better distribution of pressure on the bone, and particularly to decrease mobility of the prosthesis.

Do Large Heads Enhance Stability and Restore Native Anatomy in Primary Total Hip Arthroplasty?

Dislocation remains a serious complication in hip arthroplasty. Resurfacing proponents tout anatomic femoral head restoration as an advantage over total hip arthroplasty. However, advances in bearings have expanded prosthetic head options from traditional sizes of 22, 26, 28, and 32 mm to diameters as large as 60 mm. Large heads reportedly enhance stability owing to increased range of motion before impingement and increased jump distance to subluxation. Available larger diameter material combinations include metal- or ceramic-on-highly crosslinked polyethylene and metal-on-metal, each with distinct advantages and disadvantages. We sought to determine (1) if using larger diameter heads has lowered our dislocation rate; and (2) how closely an anatomic metal-on-metal bearing with diameters to 60 mm replicates native femoral head size. We retrospectively reviewed 2020 primary arthroplasties performed with large heads (≥ 36 mm) in 1748 patients and noted dislocation incidence. In a prospective subset of 89 cases using anatomic heads, native femoral head diameter was measured intraoperatively with calipers by an independent observer and later compared with implanted size. One dislocation has occurred in 2020 hips for an incidence of 0.05%. The prosthetic head averaged 0.7 mm larger than the native head with 68 of 89 (76%) reconstructed to within ± 2 mm of native size. Larger diameter heads have contributed to lower dislocation rates and large-diameter metal-on-metal articulation can provide close anatomic restoration in primary THA.

Measurement of femoral head penetration in polyethylene using a 3-dimensional CT-scan technique

Background Current techniques for measuring in vivo polyethylene wear suffer from a range of problems, resulting in an unacceptable lack of repeatability and/or insufficient accuracy when they are used to measure the low wear rates associated with new, highly crosslinked polyethylene. We describe an improved CT method for measurement of 3D femoral head penetration in PE acetabular cups that has sufficient accuracy and repeatability to allow assessment of the wear potential of modern implants.Method The accuracy and repeatability of the CT-scan method was determined by blindly repeating measurements on a precisely calibrated 28-mm prosthetic head and by comparing them with direct metrological measurements on 10 acetabular specimens with in vitro wear from machining, and on 8 explanted acetabular specimens with in vivo wear.Results The intra- and interobserver errors in femoral head diameter were 0.036 mm (SD 0.044) and 0.050 mm (SD 0.022), respectively. CT estimated femoral head penetration in both all-poly and metal-backed acetabular components with accuracy ranging from 0.009 to 0.245 mm (mean 0.080; SD 0.067).Interpretation We found that the CT method is rapid, is accurate, and has repeatability and ease of availability. Using a slice thickness of 0.0625 mm, this method can detect wear—and also the threshold for the wear rate that causes osteolysis—much earlier than previous methods.

50 Years ago in CORR: Complications in replacement arthroplasty of the hip; experience with 68 additional cases Howard Mendelsohn, MD and Bernard N. Becker, MD CORR 1955;6:48-53.

This month’s symposium is devoted to complications in total joint arthroplasty. Surgeons have always been concerned about complications of their operations, and arthroplasty is no exception. Arthroplasty arises from two Greek words, arthros meaning joint and plastikos related to molding. The concept has been attributed to John Rhea Barton of Philadelphia, who osteotomized the upper end of the femur of a patient with a spontaneous joint fusion, and by moving the osteotomy site created a mobile yet stable pseudarthrosis [2]. However, subsequent investigators in the late 1800s and early 1900s used an innovative array of approaches, primarily by inserting foreign materials between the joint surfaces [1, 7]. Smith-Petersen introduced the use a Vitallium cup between the acetabulum and femoral head in the 1930s, undoubtedly achieved greater success than earlier investigators [8, 9]. Perhaps the first attempt to actually replace both joint surfaces was that of Themistocles Gluck, who in 1894 described his efforts to fashion joint surfaces from ivory [7], but he reported no followup. Later authors, including Moore [6] and Thompson [10] used metal to replace only one side of the joint (hemiarthroplasty). The earliest successful attempts to replace both sides of the joint were reported by Charnley in 1961 [3] and McKee and Watson-Farrar in 1965 [11]. All reported complications, including those reported by Charnley: the disastrous wear of Teflon as a bearing material [4] and high infection rates [5]. Mendelsohn and Becker reported high complication rates using hemiarthroplasty, including deaths in 12 of 66 patients (18%) (Table 2). One hundred fourteen other mostly major complications occurred in 53 of the 66 patients. These included migration and erosion of bone (Fig. 5). They concluded, “It is not our intention to evaluate preoperative indications, but, in view of the dismal picture portrayed by this statistical survey, it is our strong clinical impression that this operation should be regarded as a procedure of last resort for carefully selected patients in the older-age group.” All of these early pioneers and users of these various sorts of approaches had high complication rates. Had they not persisted, we would not have today what is undoubtedly one of the most effective operations ever developed for relieving pain and restoring function: total hip arthroplasty has relieved and enhanced the quality of life for millions of patients worldwide. If complications occur far less commonly today, and if the very large majority of patients (over 90%) retain excellent function for ten years or more, complications for those unfortunate few who develop them remain a major challenge for the patients and for their doctors. Table 2 Fig. 5 Eicher prosthesis. (Left) Three months after operation. The prosthetic head has migrated superiorly and does not articulate with the acetabular fossa. (Right) Twenty-one months later, showing creation of a secondary acetabular fossa with progressive superior ...