Background. Structural bone allografts are an established treatment method for long-bone structural defects arising from such conditions as trauma, sarcoma, and osteolysis following total joint replacement. However, the quality of structural bone allografts is difficult to non-destructively assess prior to use. The functional lifetime of structural allografts depend on their ability to resist cyclic loading, which can lead to fracture even at stress levels well below the yield strength. Because allograft bone has limited capacity for remodeling, optimizing allograft selection for bone quality could decrease long-term fracture risk. Raman spectroscopy biomarkers can non-destructively assess the three primary components of bone (collagen, mineral, and water), and may predict the resistance of donor bone allografts to fracture from cyclic loads. The purpose of this study was to prospectively assess the ability of Raman biomarkers to predict number of cycles to fracture (“cyclic fatigue life”) of human allograft cortical bone. Methods. Twenty-one cortical bone specimens were from the mid-diaphysis of human donor bone tissue (bilateral femurs from 4 donors: 63M, 61M, 51F, 48F) obtained from the Musculoskeletal Transplant Foundation. Six Raman biomarkers were analyzed: collagen disorganization, type B carbonate substitution (a surrogate for mineral maturation), matrix mineralization, and 3 water compartments. Specimens underwent cyclic fatigue testing under fully reversed conditions at 35 and 45MPa (physiologically relevant stress levels for structural allografts). Specimens were tested to fracture or to 30 million cycles (“run-out”), simulating 15 years of moderate activity (i.e., 6000 steps per day). Multivariate regression analysis was performed using a tobit model (censored linear regression) for prediction of cyclic fatigue life. Specimens were right-censored at 30 million cycles. Results. All of the 6 biomarkers that were evaluated were independently associated with cyclic fatigue life (p < 0.05). The multivariate model explained 70% of the variance in cyclic fatigue life (R2=0.695, p<0.001,). Increasing disordered collagen (p<0.001) and loosely collagen-bound water compartments (p<0.001) were associated with decreased cyclic fatigue life. Increasing type B carbonate substitution (p<0.001), matrix mineralization (p<0.001), tightly collagen-bound water (p<0.001), and mineral-bound water (p=0.002) were associated with increased cyclic fatigue life. In the predictive model, 42% of variance in cyclic fatigue life was attributable to degree of collagen disorder, all bound water compartments accounted for 6%, and age and sex accounted for 17%. Conclusions. Raman biomarkers of three bone components (collagen, mineral, and water) predict cyclic fatigue life of human cortical bone. Increased baseline collagen disorder was associated with decreased cyclic fatigue life, and was the strongest determinant of cyclic fatigue life. Increased matrix mineralization and mineral maturation were associated with increased cyclic fatigue life. Bound-water compartments of bone contributed minimally to cyclic fatigue life. These results are complementary with prior Raman studies of monotonic testing of bone that reported decreased toughness and strength with increased collagen disorder and increased stiffness with increased bone mineralization and mineral maturation. This model should be prospectively validated. Raman analysis is a promising tool for the non-destructive evaluation of structural bone allograft quality and may be useful as a screening tool for selection of allograft bone. Acknowledgements. Supported by a grant from the Musculoskeletal Transplant Foundation. The Dudley P. Allen Fellowship (JYD), Wilbert J. Austin Professor of Engineering Chair (CMR) and the Leonard Case Jr. Professor of Engineering Chair (OA) are gratefully acknowledged

Total Hip Arthroplasty (THA) surgery is a physical and cognitive challenge for surgeons. Data on stress levels, cognitive and physical load of orthopaedic surgeons, as well as ergonomic impact, are limited. With and without the use of an automated impaction device, operational efficiency and the surgeon's ergonomic, mental, and physical load was investigated. In a total of thirty THA procedures, a standard manual technique was compared with an automated impaction device. Three computerized cognitive tasks (Simon, pattern comparison, and pursuit rotor) and five physical tests (isometric wall-sit, plank-to-fatigue, handgrip, supra-postural task, and shoulder endurance) were used to assess psychophysiological load of the surgeon. Surgeon's cortisol concentration was evaluated from saliva samples. Postural risk was assessed by Rapid Upper Limb Assessment (RULA) and Rapid Entire Body Assessment (REBA). Efficiency was assessed by timing surgical steps and instrumentation flow. Cognitive performances after automated impaction showed faster response times and lower error rates with a greater time-on-target (+1.5 s) and a lower mouse deviation from target (−1.7 pixels). Manual impaction showed higher physical exhaustion in the isometric wall-sit test (10.6% vs. 22.9%), plank-to-fatigue (2.2% vs. 43.8%), the number of taps in the supra-postural task (−0.7% vs. −7.7%), handgrip force production in the dominant (−6.7% vs. −12.7%) and contralateral hand (+4.7% vs. +7.7%), and in shoulder endurance (−15s vs. −56s). An increase of 38.2% in salivary cortisol concentration between the midday (1.31 nmol/l) and afternoon session (1.81 nmol/l) was observed with manual impaction. After using automated impaction, salivary cortisol concentration decreased (−51.2%). Manual broaching time was on average 6′20’’ versus 7’3’’ with automated impaction. RULA of manual impaction scored 6 for cup impaction and 5 for femoral broaching, versus 3 and 3 for automated impaction, respectively. REBA of manual impaction scored 9 for cup impaction and 5 for femoral broaching, versus 4 and 3 for automated impaction, respectively. Automated impaction lowers surgeons’ cognitive and physical fatigue and leads to reduced stress and improved ergonomics without loss of surgical efficiency

The incidence and long-term outcome of undisplaced fatigue fractures of the femoral neck treated conservatively were examined in Finnish military conscripts between 1970 and 1990. From 106 cases identified, 66 patients with 70 fractures were followed for a mean of 18.3 years (11 to 32). The original medical records and radiographs were studied and physical and radiological follow-up data analysed for evidence of risk factors for this injury. The development of avascular necrosis and osteoarthritis was determined from the follow-up radiographs and MR scans. The impact of new military instructions on the management of hip-related pain was assessed following their introduction in 1986. The preventive regimen (1986) improved awareness and increased the detected incidence from 13.2 per 100 000 service-years (1970 to 1986) to 53.2 per 100 000 (1987 to 1990). No patient developed displacement of the fracture or avascular necrosis of the femoral head, or suffered from adverse complications. No differences were found in MRI-measured hip joint spaces at final follow-up. The mean Harris Hip Score was 97 (70 to 100) and the Visual Analogue Scale 5.85 mm (0 to 44). Non-operative treatment, including avoidance of or reduced weight-bearing, gave favourable short- and long-term outcomes. Undisplaced fatigue fractures of the femoral neck neither predispose to avascular necrosis nor the subsequent development of osteoarthritis of the hip

Fracture of contemporary femoral stems is a rare occurrence. Earlier THR stems failed due to design issues or post manufacturing heat treatments that weakened the core metal. Our group identified and analyzed 4 contemporary fractured femoral stems after revision surgery in which electrochemical welds contributed to the failure. All four stems were proximally porous coated titanium alloy components. All failures occurred in the neck region post revision surgery in an acetabular cup exchange. All were men and obese. The fractures occurred at an average of 3.6 years post THR redo (range, 1.0–6.5 years) and 8.3 years post index surgery (range, 5.5–12.0 years). To demonstrate the effect of electrocautery on retained femoral stems following revision surgery, we applied intermittent electrosurgical currents at three intensities (30, 60, 90 watts) to the polished neck surface of a titanium alloy stem under dry conditions. At all power settings, visible discoloration and damage to the polished neck surface was observed. The localized patterns and altered metal surface features exhibited were like the electrosurgically-induced damage priorly reported. The neck regions of all components studied displayed extensive mechanical and/or electrocautery damage in the area of fracture initiation. The use of mechanical instruments and electrocautery was documented to remove tissues in all 4 cases. The combination of mechanical and electrocautery damage to the femoral neck and stem served as an initiation point and stress riser for subsequent fractures. The electrocautery and mechanical damage across the fracture site observed occurred iatrogenically during revision surgery. The notch effect, particularly in titanium alloys, due to mechanical and/or electrocautery damage, further reduced the fatigue strength at the fractured femoral necks. While electrocautery and mechanical dissection is often required during revision THA, these failures highlight the need for caution during this step of the procedure in cases where the femoral stem is retained

Background. One of the potential complications of polyethylene liner (PL) is its dissociation from the metal shell. This is a rare but catastrophic complication of total hip replacement (THR). Objective. was to analyze the retrieved dissociated components (PL and shell) (Depuy Pinnacle, Warsaw, IN, USA) to evaluate the mechanism of failure. All these components were dissociated within four years of implantation. Methods. Components were retrieved from three different centers in Canada over the period from January 2011 to October 2016. The analysis was done at the Orthopaedic Innovation Centre (OIC) in Winnipeg Canada. Nine PLs were retrieved at the time of revision THR. Assessment using optical and scanning electron microscopies at magnification between 25× and 150× was performed. The following questions were asked: 1) were the liners correctly seated at the primary surgery? 2) Are there signs of impingement present which could have caused the liner to become dissociated? 3) Does the wear pattern indicate that the liner was failing prior to dissociation?. Results. All PLs dissociated in the inferior direction. Five PL were believed to have been seated properly at the time of indexed surgery. All PL displayed signs of post dissociation impingement. Only 1 PL had fractured resulting in failure prior to dissociation. Other PL showed signs of wear, however none of them reached thinness that would be a cause for concern. Eight PLs demonstrated shearing of the anti rotation tabs. Assessment of the anti rotation tabs revealed that a couple had sheared off suddenly while remaining anti rotation tabs sheared off in progressive fatigue resulting in the failure of the locking mechanism. Conclusions. Retrieval analysis was useful in identifying common patterns of failure such as anti-rotation tab damage. This was suggestive that the locking mechanism of the acetabular components has probably failed in 8 out of 9 of the retrieved liners

Aims

The risk of mechanical failure of modular revision hip stems is frequently mentioned in the literature, but little is currently known about the actual clinical failure rates of this type of prosthesis. The current retrospective long-term analysis examines the distal and modular failure patterns of the Prevision hip stem from 18 years of clinical use. A design improvement of the modular taper was introduced in 2008, and the data could also be used to compare the original and the current design of the modular connection.

Aims

The primary outcome was investigating differences in wear, as measured by femoral head penetration, between cross-linked vitamin E-diffused polyethylene (vE-PE) and cross-linked polyethylene (XLPE) acetabular component liners and between 32 and 36 mm head sizes at the ten-year follow-up. Secondary outcomes included acetabular component migration and patient-reported outcome measures (PROMs) such as the EuroQol five-dimension questionnaire, 36-Item Short-Form Health Survey, Harris Hip Score, and University of California, Los Angeles Activity Scale (UCLA).

Aims

Pelvic discontinuity is a rare but increasingly common complication of total hip arthroplasty (THA). This single-centre study evaluated the performance of custom-made triflange acetabular components in acetabular reconstruction with pelvic discontinuity by determining: 1) revision and overall implant survival rates; 2) discontinuity healing rate; and 3) Harris Hip Score (HHS).

Aims

The Single Assessment Numerical Evalution (SANE) score is a pragmatic alternative to longer patient-reported outcome measures (PROMs). The purpose of this study was to investigate the concurrent validity of the SANE and hip-specific PROMs in a generalized population of patients with hip pain at a single timepoint upon initial visit with an orthopaedic surgeon who is a hip preservation specialist. We hypothesized that SANE would have a strong correlation with the 12-question International Hip Outcome Tool (iHOT)-12, the Hip Outcome Score (HOS), and the Hip disability and Osteoarthritis Outcome Score (HOOS), providing evidence for concurrent validity of the SANE and hip-specific outcome measures in patients with hip pain.

Aims

Manual impaction, with a mallet and introducer, remains the standard method of installing cementless acetabular cups during total hip arthroplasty (THA). This study aims to quantify the accuracy and precision of manual impaction strikes during the seating of an acetabular component. This understanding aims to help improve impaction surgical techniques and inform the development of future technologies.

Aims

Limited implant survival due to aseptic cup loosening is most commonly responsible for revision total hip arthroplasty (THA). Advances in implant designs and materials have been crucial in addressing those challenges. Vitamin E-infused highly cross-linked polyethylene (VEPE) promises strong wear resistance, high oxidative stability, and superior mechanical strength. Although VEPE monoblock cups have shown good mid-term performance and excellent wear patterns, long-term results remain unclear. This study evaluated migration and wear patterns and clinical and radiological outcomes at a minimum of ten years’ follow-up.

Aims

The aim of the study was to investigate whether the primary stability of press-fit acetabular components can be improved by altering the impaction procedure.

Aims

Hip arthroscopy (HA) has become the treatment of choice for femoroacetabular impingement (FAI). However, less favourable outcomes following arthroscopic surgery are expected in patients with severe chondral lesions. The aim of this study was to assess the outcomes of HA in patients with FAI and associated chondral lesions, classified according to the Outerbridge system.

Aims

Hip dysplasia (HD) leads to premature osteoarthritis. Timely detection and correction of HD has been shown to improve pain, functional status, and hip longevity. Several time-consuming radiological measurements are currently used to confirm HD. An artificial intelligence (AI) software named HIPPO automatically locates anatomical landmarks on anteroposterior pelvis radiographs and performs the needed measurements. The primary aim of this study was to assess the reliability of this tool as compared to multi-reader evaluation in clinically proven cases of adult HD. The secondary aims were to assess the time savings achieved and evaluate inter-reader assessment.

We describe three cases of fracture of the titanium JRI-Furlong hydroxyapatite-ceramic (HAC)-coated femoral component. We have examined previous case reports of failure of this stem and conclude that fracture may occur in two places, namely at the neck-shoulder junction and at the conical-distal cylindrical junction. These breakages are the result of fatigue in a metallurgically-proven normal femoral component. All the cases of failure of the femoral component have occurred in patients with a body mass index of more than 25 in whom a small component, either size 9 or 10, had been used. In patients with a body mass index above normal size 9 components should be avoided and the femoral canal should be reamed sufficiently to accept a large femoral component to ensure that there is adequate metaphyseal fixation

Symptomatic cobalt toxicity from a failed total hip replacement is a rare but devastating complication. It has been reported following revision of fractured ceramic components, as well as in patients with failed metal-on-metal articulations. Potential clinical findings include fatigue, weakness, hypothyroidism, cardiomyopathy, polycythaemia, visual and hearing impairment, cognitive dysfunction, and neuropathy. We report a case of an otherwise healthy 46-year-old patient, who developed progressively worsening symptoms of cobalt toxicity beginning approximately six months following synovectomy and revision of a fractured ceramic-on-ceramic total hip replacement to a metal-on-polyethylene bearing. The whole blood cobalt levels peaked at 6521 µg/l. The patient died from cobalt-induced cardiomyopathy. Implant retrieval analysis confirmed a loss of 28.3 g mass of the cobalt–chromium femoral head as a result of severe abrasive wear by ceramic particles embedded in the revision polyethylene liner. Autopsy findings were consistent with heavy metal-induced cardiomyopathy. We recommend using new ceramics at revision to minimise the risk of wear-related cobalt toxicity following breakage of ceramic components. Cite this article: Bone Joint J 2013;95-B:31–7

Introduction. The use of larger femoral heads in Total Hip Arthroplasty has increased in order to reduce the risk of dislocation and to improve the range of motion of the joint. In 2003, within the UK, the “standard” head size of 28mm was used in 73% of all hip procedures, whereas by 2012, this figure dropped to 36%. Concerns regarding the impact of this increment in head size on the cement and bone stresses have arisen; however, this has yet to be clearly determined. Methods. To understand the relationship between femoral head size and cement mantle and bone stress in cemented hip arthroplasty, 3D-Finite-Element models of a hemipelvis with cemented cup[tb6] (50mm outer-diameter) were developed. Loading conditions of single-leg-stance (average and overweight) were simulated for three head sizes (28, 32 and 36mm). The models were validated with an in-vitro experiment using the average loading condition. Results. Stresses were evaluated at the periacetabular bone and cement mantle. In the pelvic bone the peak von Mises stress value presented no change in magnitude due to change in head size for the average patient; for the overweight patient, there was a small increment. In the cement mantle, there was a noticeable difference in the pattern distribution and magnitude of the stresses for the two loading conditions[tb7]. For the average patient, average stresses in the cement were 1.7MPa, 1.8MPa and 1.9MPa for 28, 32 and 36mm heads, respectively; whereas for the overweight patient the stresses were 3.4MPa, 3.6MPa and 3.8MPa. Conclusions. Pelvic bone remained largely unaffected by the changes in femoral head size. The major effect of femoral head size occurs in the stress level and stress distribution pattern in the cement mantle. The current predicted cement stresses are below the cement endurance limit, this indicates that the cement fatigue life is not affected by the increasing head size

Aims

The aim of this study was to compare the cost-effectiveness of cemented hemiarthroplasty (HA) versus hydroxyapatite-coated uncemented HA for the treatment of displaced intracapsular hip fractures in older adults.

Introduction. Modularity in femoral stem designs allow surgeons to independently control leg length, offset, and femoral version in revision or complex primary THA cases. Initial enthusiasm in these modular stems has been tempered by recognition of modular junction failures. This study evaluates mean 5-year clinical results and survival rates of a 3-part titanium alloy modular femoral implant with unique taper geometries and a metaphyseal plasma spray surface. The current results are presented after pre-market independent fatigue testing performed by Orthopaedic Laboratory (Greenwald) and previously published early clinical results in 2006. Low plasticity burnishing (LPB) was added in 2005 to further strengthen the neck metaphyseal modular junction. The modular stem component is a polished cylindrical splined clothespin design. Our hypothesis is that these unique modular junctions succeed in offering the advantages of modularity without failure at this midterm follow-up period. Methods. Between May 2010 and July 2016, 32 total hip arthroplasties were performed using a 3-part femoral stem with neck-metaphyseal-stem modular junctions. Surgeries were either the final stage of a two-stage revision for infection, revision THR for loosening, or a revision of a previous non-prosthetic replacement procedure. Patients were entered into an IRB-approved registry and followed with x-rays, HHS, Oxford scores, and patient satisfaction scores. Patients who failed to return for routine follow-up were contacted by phone or email. Two patients had died with their implants intact. Six patients could not be reached for an updated follow-up. One stem was revised for loosening at 33 months due to failed osseointegration in a patient with chronic renal failure. This removed stem was submitted for taper exam and sectioning. Results. There were 23 patients for evaluation at a mean 61 months (range 21–98). Mean patient age at implantation was 56 (range 25–88), BMI was 27 (range 20–40). There were no modular junction failures. Modular junctions examined in the retrieved implant did not demonstrate any abnormalities other than normal wear properties. HHS and OHS scores both improved between pre-op and final follow-up, 23 to 85 and 17 to 43, respectively. Average patient satisfaction score at final follow-up was 9.8 out of 10 (min 8, max 10). Radiographic examination showed stem subsidence > 2mm and radiolucencies around the metaphyseal cone in 1 patient, the same patient who required implant removal. Radiolucencies were seen along the polished stem tip in 43% of cases, spot welding at the distal metaphyseal cone in 67% of cases, and mild proximal-medial stress shielding in 33% of cases. Conclusion. This unique 3-part modular stem with metaphyseal fixation shows good functional and radiographic results at 5-year follow-up. There were no junctional failures. One stem was removed due to failure to osseointegrate and showed no worrisome taper abnormalities. Spot welding is common around the plasma spray metaphyseal cone. Implant removal, if necessary, only requires disruption of the metaphyseal fixation. Further follow-up will be important to confirm our confidence in this unique stem design

Aims

This study reports the ten-year wear rates, incidence of osteolysis, clinical outcomes, and complications of a multicentre randomized controlled trial comparing oxidized zirconium (OxZr) versus cobalt-chrome (CoCr) femoral heads with ultra-high molecular weight polyethylene (UHMWPE) and highly cross-linked polyethylene (XLPE) liners in total hip arthroplasty (THA).