Cemented total hip arthroplasty yields reliable results in short to medium term studies, but aseptic loosening remains a problem in long-term follow up, especially in young and active patients. Aseptic loosening has been related to wear, and in order to minimize wear various alternatives to the traditional metal on polyethylene have been proposed. Both ceramic on polyethylene (COP) and metal on metal (MOM) have been shown to produce less wear than metal on polyethylene (MOP). In order to study the effect of the bearing, we have utilized identical stems and cups while comparing the different bearings. Methods and material. 396 hips were randomized to MOP, COP or MOM using a cemented triple tapered polished stem (MS-30; Sulzer Orthopedics) with a cemented polyethylene cup (Weber; Sulzer, Orthopedics) and a 28 millimeter head. For the MOP and COP articulations, a all-polyethylene cup was used with a Protasul™ metal head or a Sulox™ alumina head, whereas a polyethylene cup with metal insert was used for the MOM articulations (Weber Polyethylene Cup with Metasul™ Insert) with a Metasul™ metal head. Harris Hip Score (HHS) and radiological evaluation was performed after two, five and seven years. Ethical approval was obtained. Results. HHS was available for 338 hips after seven years. The HHS in the MOP group (116 hips) was 93.7 (SD 9.0), 93.5 in the COP group (112 hips) (SD 8.8), and 91.0 (SD 13.4) in the MOM group (110 hips). Radiographic evaluation was available for 335 hips. Radiolucencies around the stem larger than one millimeter were found in five of 115 MOP hips, seven of 111 COP hips and in seven of 110 MOM hips. Periacetabular radiolucencies identified as larger than one millimeter were found in none of the 116 MOP hips, five of the 112 COP hips and in 19 of the 110 MOM hips. Ten revisions were performed. In the MOP group there were three revisions (infection, dislocation, pain); one in the COM group (infection), and six in the MOM group (three infections, two aseptic loosening and one septic loosening). Discussion. Clinically, the three bearing types perform equally well at seven years, and there are few signs of impending failure for the stem. However, there are an alarmingly high proportion of cups showing signs of loosening. Two hips have been revised in the MOM group for aseptic loosening as opposed to none in the two other groups, which adds to the concern. The MOM articulation used in this study should be monitored closely for signs of aseptic loosening

Introduction. The advantages of metal on metal (MOM) hip replacement are decreased wear rate, preservation of bone stock, anatomical restoration and enhanced stability. Large amounts of metal wear particles and metal ions are released which may induce adverse reactions including local soft tissue toxicity, hypersensitivity reactions, bone loss and risk of carcinogenesis. Aseptic loosening can be the result of a peri prosthetic osteolysis generated as a result of a biological response to particulate wear debris. Our aim in this study was to determine whether a steeply inclined acetabular component would give rise to a higher concentration of metal ions. Patients and methods. Between April 2003 and June 2006, 22 patients had MOM hip replacement for osteoarthritis by a single Surgeon. There were 12 male and 10 female patients. The average age at the time of surgery was 56 years (Range: 44–69 years). We divided the 22 patients into 2 groups, one group (A) of 11 patients with the acetabular inclination angle more than 50 degrees and the other group (B) of 11 patients with the angle less than 50 degrees. The inclination of the acetabular cup was measured using a standard AP radiograph of the pelvis. The patients had metal ion levels (blood chromium and serum cobalt) measured at an average follow up of 3.2 years (Range 2.4 to 5 years). Results. Mean blood chromium level in the group A (146 nM/L) was significantly higher (p=0.005) than in Group B (92 nM/L). Mean serum cobalt level in the group A (245 nM/L) was significantly higher (p=0.002) than in Group B (110 nM/L). Discussion. The early to mid term published results of MOM hip replacements have been encouraging. There are, however, a number of concerns about the MOM bearing. Although its wear rate is low, it still releases metal ions into the body particularly cobalt and chromium since most metal on metal bearings are made of a cobalt chromium alloy. The long-term consequences of increased levels of these ions in the body are not known. High concentrations of Co and Cr are toxic and are known to interfere with a number of biological functions. There also have been recent reports of soft tissue reactions with MOM hip replacement. In the light of these concerns, it is important to examine factors which may influence the release of metal ions after MOM hip replacement. It has been reported in the recent literature that the position of the acetabular component will influence the bearing wear inturn leading to the release of metal ions after MOM hip replacement. Our findings indicate that steeply inclined acetabular components with an inclination angle greater than 50 degrees gives rise to higher concentration of metal ions

Introduction. Metal on metal articulations produce chromium (Cr) and cobalt (Co) debris, particularly when the articulations are worn in. High levels in the peripheral blood are indicative of excess wear and may cause adverse effects. The present RCT investigates metal ion levels and the relationship of Co, Cr ions and lymphocyte counts during the running-in period. Materials and Methods. Following randomization to RHA (ASRTM, DePuy) or THA we obtained whole blood (wb), and serum (s) samples at baseline, 8 w, 6 m and 1 y. We measured the Co and Cr concentrations, the total lymphocyte count as well as the CD3+, CD4+, CD8+, CD19+ and CD16+/CD56+ sub populations. Cup inclination and anteversion angles came from conventional radiographs. Activity was measured as steps by pedometer and UCLA activity. Data are presented as median (range). Results. We had 19 patients in each group. Age 57 (46–64) y (RHA) and 55 (44–64) y (THA). RHA only: head size: 51 (47 to 57)mm, cup inclination: 45.0 (40- 56)° and anteversion: 23 (7–38)°. The ion concentrations stayed below 0.2 ppb for THAs. For RHAs the Co and Cr concentrations generally rose markedly in the initial 8 weeks, followed by a slower ascent up to 1 year to wb Co: 1.0 (0.6–5.2), s Co: 1.3 (0.7–6.5), wb Cr: 1.3 (0.4–8.0) and s Cr: 1.7 (0.6–15) ppb. A high ion level was correlated to a small head size (p<0.03) and a cup inclination around 45° (p<0.04). We could not correlate the ion concentrations to the anteversion or the activity levels. The absolute lymphocyte counts were not always identical in the groups (eg. lower CD8+ for RHA) but there was no group difference when we analysed the change from baseline. We did not demonstrate any correlation between metal ion levels and lymphocyte subpopulations. Discussion. The findings of this study does not support the theory that metal ions suppress the lymphocytes or the CD8+ in particular (Hart et al., 2009). Our conclusions are limited by low numbers, but we suspect the theory could be biased by missing baseline values. Our study did not demonstrate the same 6–9 months ion peak found in other running-in studies (Back et al., 2005, Heisel et al., 2008), but rather a slow continuous rise with lower median ion concentrations. It could indicate lower wear or perhaps a longer running in period in our slightly older population. Contrary to our expectations we found that cups placed in optimal inclination displayed a higher ion level. Most of the smallest cups were found in this group, and the majority of the steep cups had very large heads. For this implant head size may be more important than cup position

In a randomized study of 60 patients allergic reactions are evaluated in three joint prosthesis groups, a resurfacing arthroplasty (ReCap), a non-cemented, large metal-on-metal head (Bimetric Magnum) and a non-cemented, alumina ceramic-on-ceramic bearing in a titanium shell (Bimetric C2a). The inclusion criteria were osteoarthritis, ASA I–II, MRI-scan without caput necrosis, DXA-scan without osteoporosis. The exclusion criteria were short neck (<2cm.), large cysts (>1cm.), medical treatment affecting the bone metabolism, severe deformity of the femoral head, impaired kidney function and inability to co-operate. Blood samples were drawn prior to and 6 weeks, 6 months, 1 year, and 3 years after surgery; two tubes from which plasma was prepared, and two tubes for serum. From the last included 20 patients in each group was also taken blood one and three years after surgery for an in vitro lymphocyte assay for scoring of possible hypersensitivity to prosthesis metals. The isolated lymphocytes were subjected to measurement of proliferation and expression of CD69 by flow cytometry and measurement of the Migration Inhibitory Factor (MIF) by ELISA. Plasma concentrations of the cytokines IL-1, IL-4, IL-6, IL-8, IL-12p70, IL-15, interferon-and osteoprotegerin were determined by multiplex-immunoassay. Serum concentrations of chromium and cobalt were determined by graphite furnace atomic absorption spectrometry. The serum concentrations of chromium and cobalt were lowest in patients with the C2a implant and highest with Magnum, some of these differences were significant at 6 weeks, 6 months, and 1 year after surgery. No patient had a very high serum metal concentration. The values of the variables measured in the in vitro lymphocyte assay mainly changed in the expected direction depending on the concentration of the same metal in the serum sample drawn at the same time, but no significant correlation was seen. One patient had uncertain symptoms of metal hypersensitivity and relatively high serum metal concentrations 3 years after arthroplasty with a Magnum prosthesis and was assessed extraordinarily, and elicited the marginally highest MIF responses in the lymphocyte assay. A strong correlation was found between the plasma concentrations of most cytokines, but the cytokine concentrations were not correlated to contemporary metal concentrations

Background. Wear particles are considered to be the major culprit for the aseptic loosening. Their characterization is thus crucial for the understanding of their bioreactivity and contribution to the development of aseptic loosening. Methods. Metal wear debris particles were analyzed directly in periprosthetic tissue resins by scanning electron microscopy (SEM) combined with back-scattered electron imaging (BSE) and energy dispersive X-ray spectroscopy (EDS). Four groups of tissue samples retrieved at revision operations of loosened hip implants with different bearing surfaces (metal-on-metal, ceramic-on-polyethylene and metal-on-polyethylene), and different material of the femoral stem (Ti alloy, CoCrMo and polymer combined with stainless steel) were investigated. Tissue samples were first analyzed histologicaly. Sections from the same paraffin blocks were then carbon coated and analyzed using SEM/BSE/EDS method. Results. Metal particles were detected in all samples. Their composition corresponded to the composition of the implant components. The gradation of metal particles ranged from +1 to +3. A considerable number of big metal particles were actually agglomerates of submicron particles visible only at higher magnification. The clustering of particles was observed primarily for CoCrMo and, to a lesser extent, for stainless steels particles. The median sizes of CoCrMo clusters in two groups of samples were 2.9 1.8 m (range, 0.5 to 7.6 m) and 3.2 1.0 m (range, 1.9 to 5.4 m). The effect of clustering was not observed for Ti particles. The median sizes of individual Ti particles determined in two groups of samples were 2.5 3.6 m (range, 0.4 to 17.3 m) and 4.3 2.8 m (range, 0.8 to 11.0 m). Conclusion. Scanning electron microscopy combined with back-scattered electron imaging is an appropriate and selective method to recognize metal particles in tissue sections, without being destructive to specimens. When the size of the particles is considered, however, it should be differed between the size of individual particles and size of clusters of particles. Besides its benefits, this study has some limitations: the detection of particles smaller than 0.4 m is difficult, and this method cannot be used to identify polyethylene particles

Introduction. Large diameter metal on metal cups have been used in total hip arthroplasty advocating superior results with respect to dislocation rates, range of motion and long term survival. The Durom cup used as part of the Durom hip resurfacing system has been incriminated with poor short term results sometimes correlated to incorrect positioning of either the femoral or acetabular component. Our objective was to evaluate short term results of the Durom cup used in conjunction with standard stems. Methods. We prospectively followed all patients with a large diameter metal-on-metal articulation (Durom) and a standard stem operated upon between 9/2004 and 9/2008. Patients were seen at follow-up for a clinical (Harris hip score=HHS, UCLA scale and patient satisfaction), radiographic and questionnaire assessment. Results. 89 primary THAs in 80 patients (74% men) with a mean age of 52 (±12) years were included. Main diagnoses were primary osteoarthritis in 47% and aseptic necrosis in 35%. An uncemented stem was used in 79%. Overall, 80 THAs were controlled at a mean follow-up of 39 months (range 16–67 months), 4 patients were lost to follow-up and 5 patients refused or were unable to attend the visit. However, none of the 5 underwent revision. Overall, 8 THAs (8/85, 9.4%) were revised in mean 28 months (range 8–60) after the operation. One additional patient was awaiting revision for aseptic loosening of both cup and stem. The reasons for revision were aseptic loosening in three cases, presence of a granuloma (histological diagnosis of ALVAL) in three, deep infection in one and impingement in one case. Radiographic analysis revealed linear (n=2) and focal (n=3) osteolysis as well as early cup migration (n=2). In 5 revised patients no radiographic changes were found. 56 (70%) of the 80 patients with follow-up had a HHS between 80 and 100. Among those who were not revised, the mean HHS improved from 55.2 to 88.4 (mean increase 33.2, 95% CI 27.7; 38.7). The mean activity level (UCLA scale) at follow-up was 6.4 (±1.8). Overall, mild to severe pain was reported in 14 cases and occasional pain in 22. Groin pain was present in 18 patients (22.5%), 7 of them belonged to the revised group. 61 (76.3%) of the 80 patients with follow-up were satisfied. Mean patient satisfaction on the VAS scale among those who were not revised was 9.0 (±1.3). Conclusion. This study confirms the increased short-term revision rate of the large diameter metal-on-metal couple (Durom) reported by others. In all revision cases the retrieved cups showed no osteo-integration and were removed easily. The operative indication for revision was based upon groin pain and patient dissatisfaction. Radiographic signs of implant loosening were not always present even though in all revised cases except for one the cup was found loose

Objectives

Osteochondral ankle defects (OCDs) mainly occur in a young, active population. In 63% of cases the defect is located on the medial talar dome. Arthroscopic debridement and microfracture is considered the primary treatment for defects up to 15 mm. To treat patients with a secondary OCD of the medial talar dome, a 15-mm diameter metal implant (HemiCAP ®) was developed. The set of 15 offset sizes was designed to correspond with the anatomy of various talar dome curvatures. Recently, two independent biomechanical cadaver studies were published, providing rationale for clinical use. The present study was undertaken to evaluate the clinical effectiveness and safety of the metal implantation technique for osteochondral lesions of the medial talar dome in a prospective study.

Introduction. Osteochondral lesions (OCLs) of the talus are a challenging and increasingly recognized problem in chronic ankle pain. Many novel techniques exist to attempt to treat this challenging entity. Difficulties associated with treating OCLs include lesion location, size, chronicity, and problems associated with potential graft harvest sites. Matrix associated stem cell transplantation (MAST) is one such treatment described for larger lesions >15mm2 or failed alternative therapies. This cohort study describes a medium-term review of the outcomes of talar lesions treated with MAST. Methods. A review of all patients treated with MAST by a single surgeon was conducted. Preoperative radiographs, MRIs and FAOS outcome questionnaire scores were conducted. Intraoperative classification was undertaken to correlate with imaging. Postoperative outcomes included FAOS scores, return to sport, revision surgery/failure of treatment and progression to arthritis/fusion surgery. Results. 58 MAST procedures in 57 patients were identified in this cohort. The mean follow up was 5 years. There were 20 females and37males, with a mean age of 37 years (SD 9.1). 22 patients had lateral OCLS were and 35 patients had medial OCLs. Of this cohort 32patients had previous surgery and 25 had this procedure as a primary event. 15 patients had one failed previous surgery, 9 patients had two, four patients had three previous surgeries and three patients had four previous surgeries. 12 patients had corrective or realignment procedures at the time of surgery. In terms of complications 3 patients of this cohort went on to have an ankle fusion and two of these had medial malleolar metal work taken out prior to this, 5 patients had additional procedures for arthrofibrotic debridements, 1 patient had a repeat MAST procedure, 1 additional patients had removal of medial malleolar osteotomy screws for pain at the osteotomy site, there were 2 wound complications one related to the ankle and one related to pain at the iliac crest donor site. Conclusion. MAST has demonstrated positive results in lesions which prove challenging to treat, even in a “ failed microfracture” cohort. RCT still lacking in field of orthobiologics for MAST. Longer term follow up required to evaluate durability

Introduction. To determine if elite athletes can return to professional sport after MCL or posterolateral (PLC) reconstruction using LARS ligaments. The secondary aims are to demonstrate the safety and efficacy of LARS by reporting sport longevity, subsequent surgeries, and complications. Methods. A retrospective review of all extra-articular knee ligament reconstructions, utilising a LARS synthetic ligament, by 3 sports knee surgeons between 2013 and 2020 was undertaken. All elite athletes aged over 16 years and a minimum of 2 years post reconstruction were included. No LARS were used for ACL reconstructions, and they were excluded if a LARS ligament was used for a PCL reconstruction. Return to play (RTP) was defined as competing at professional level or national/ international level in amateur sport. Results. Sixty-four (84.2%) MCL reconstructions and 12 (15.8%) PLC reconstructions were included. 52 (68.4%) underwent concomitant autograft cruciate(s) reconstruction including 6 (7.8%) bicruciate reconstructions. The mean age was 25.1 years (SD +/− 4.50). 35 (46.1%) were footballers and 35 (46.1%) were rugby players. Sixty-seven athletes (88.2%) returned to elite sport, 7 (9.2%) did not RTP and RTP status was unknown for 2 (2.6%) (Figure 1). 65 out of 67 (97.0%) RTP at the same/higher Tegner level. 56 (83.6%) and 20 (57.1%) were still playing at 2- and 5-years post-surgery Six (7.9%) players required further surgery due to irritation from the metal fixation implants. One had an inflammation adjacent to the synthetic material at the femoral end and the other cases involved the tibial staples. All six cases were able to RTP. One athlete, following bicruciate /MCL surgery had the LARS removed due to laxity. There was one MCL re-rupture, sustained while jumping, 4 years after returning to football. Conclusions. Utilising LARS in extra-articular knee ligament reconstructions allows 88.2% of athletes with a variety of knee ligament injuries to return to elite sport. The results compare well regarding RTP, complication, and revision rates with the published evidence for other types of MCL and PLC grafts. This, coupled with 57% of athletes still playing 5 years post-surgery suggests the LARS is safe and effective in these cases. For any figures or tables, please contact authors directly

MHRA guidance for patients with metal on metal hip replacements (MOM) was provided in 2012 and updated in 2017 to assist in the early detection of soft tissue reactions due to metal wear debris. A large number of metal on metal hip replacements were undertaken at our trust. A program of recall for all patients with metal on metal hip replacements was undertaken and MHRA guidelines implemented. Identification and recall of all patients from 2001 with MOM hip replacements using theatre logs, patient records and consultant log books. Two consultant review of X-rays and patient records. Postal questionnaires and GP requests for cobalt & chromium blood tests. Two consultant led MOM review clinics undertaken with metal artefact reduction scans (MARS) performed following consultation in 2017. 674 patients, 297 available for review. 59 refused follow up. 87 moved out of area, 36 untraceable, 26 not MOM, 147 RIP, 22 already revised. From 297 patients 126 female, 171 male, age range 39 – 95 yrs. 126 resurfacing, 171 MOM THR. 26 patients with elevated metal ions, MARS performed of which 17 positive, 9 negative. Of 17 positive scans 10 patients asymptomatic, 7 waiting revision. A time consuming effort and additional resource was needed and supported by the trust. From 297 hips 17 positive MARs were identified (5.7%). A new database registry has been developed to track MOM patients, clinics set up for ongoing follow up with radiological protocols for imaging. An arthroplasty advanced nurse practitioner (ANP) is now trained reviewing patients independently

INTRODUCTION. The advantages of large diameter metal on metal total hip arthroplasty (MoM THA) and hip resurfacing arthroplasty are decreased wear rate, preservation of bone stock, anatomical restoration and enhanced stability. Large amounts of metal wear particles and metal ions are released which may induce adverse reactions including local soft tissue toxicity, hypersensitivity reactions, bone loss and risk of carcinogenesis. Aseptic loosening can be the result of a peri-prosthetic osteolysis generated as a result of a biological response to particulate wear debris. No reports in the literature exist as to whether circulating levels of Chromium (Cr) and Cobalt (Co) decrease upon removal of a symptomatic large diameter MoM implant or whether levels remain high due to the effect of metal ions debris left behind in the soft tissues after revision surgery. PATIENTS AND METHODS. Between June 2006 and June 2009 we undertook 44 revision surgeries of both large head MoM THAs (femoral head diameter 38mm) and metal-on-metal hip resurfacings for suspected metallosis. Mean time from original implant to revision was 4 years, 8 months (1yr 4mo–7yr 9mo). The mean follow up evaluation was 2 years and 2 months (1yr 2mo–4 years). Blood samples were taken for whole blood Cr and serum Co according to a recognised protocol and compared with reference levels indicated by the Medicines and Healthcare Regulatory Agency recommendation of less than 7ppb for Cr (130nM/L) and Co (119nM/L). RESULTS. 42 patients were found to have histological evidence of either metal allergy, metal toxicity or foreign body reaction. 2 patients had evidence of infection with no features of metal reaction. 3 patients suffered early dislocation requiring closed reduction. 1 patient had infective complications necessitating Girdlestones. 11 patients were lost to follow up, 8 patients were diagnosed pre operatively on Co and Cr levels in urine or synovial fluid aspirate alone. 23 patients had pre revision blood or serum metal ion level results available for direct comparison. Median serum Co level pre revision was 176.6nM/L, falling post revision to 5.1nM/L (p=<0.001∗). The median whole blood Cr level pre revision was 117nM/L and 19nm/L post revision (p=<0.001∗). Mean Oxford Hip Score was 23.7. DISCUSSION. This study demonstrates that at greater than one year post removal of a large diameter MoM hip implant for the indication of symptomatic metallosis or metal hypersensitivity, metal ion levels fall to almost normal levels and that outcome of revision surgery in terms of patient satisfaction is not adversely affected

INTRODUCTION. One of the recent advances in the hard-on-hard hip arthroplasty is the development of a new material of diffusion hardened oxidised zirconium (DHOxZr). The DHOxZr material consists of a ceramic layer on the top surface which is supported by a thick oxygen diffusion hardened (DH) zone underneath. With the desired properties of metal substrate, ceramic surface and a gradient structure of the oxygen diffusion zone, the DHOxZr-on-DHOxZr bearing combination is expected to produce low wear and minimal metal ions. This can possibly address the concerns associated with metal hypersensitivity associated with metal on metal bearings and fracture risk associated with ceramics. The aim of this study was to evaluate the wear of DHOxZr-on-DHOxZr as a possible hard on hard bearing combination in hips. METHODS. Three pairs of 50 mm DHOxZr prototype hip joint devices, each consisting of a DHOxZr modular head and a DHOxZr liner were wear tested in a ProSim hip joint simulator under standard testing conditions used by the Implant Development Centre (IDC), Smith & Nephew, Leamington Spa for 5 million cycles (Mc). The flexion/extension was 30° and 15°. The internal/external rotation was ± 10°. The force was Paul-type stance phase loading, with a maximum load of 3 kN and a standard ISO swing phase load of 0.3 kN. The test frequency was 1 Hz. Gravimetric analysis was carried out at 0, 0.5, 1, 2, 3, 4 & 5 million cycles. The lubricant was new born calf serum with 2 g/l sodium azide concentration diluted with de-ionised water to achieve average protein concentration of 20 g/l. Lubricant was changed every 0.25Mc during the first million cycles of the test and at every 0.33 Mc from 1 to 5Mc. RESULTS. A biphasic wear pattern was observed for the DHOxZr on DHOxZr devices during the test, with a running in phase from 0–1 Mc and a steady state phase from 1–5 Mc. At a confidence level of 95%, the mean wear rate was 0.21 ±0.06 mm3/Mc during the running-in stage, and the wear rate was reduced to 0.01 ±0.03 mm3/Mc during the steady state for the device tested. The wear volume loss of the DHOxZr on DHOxZr devices was significantly lower than that generated by CoCrMo metal on metal (MoM) devices (p < 0.05) under identical simulator test conditions

Joint registries report that 25–40% of UKR revisions are performed for pain. Proximal tibial strain and microdamage are possible causes of this “unexplained” pain. The aim of this study was to examine the effect of UKR implant design and material on proximal tibial cortical strain and cancellous microdamage. Composite Sawbone tibias were implanted with cemented UKR components: 5 fixed bearing all-polyethylene (FB-AP), 5 fixed bearing metal backed (FB-MB), and 5 mobile bearing metal backed implants (MB-MB). Five intact tibias were used as controls. Tibias were loaded in 500N increments to 2500N. Cortical surface strain was measured using digital image correlation (DIC). Cancellous microdamage was measured using acoustic emission (AE), a technique which detects elastic waves produced by the rapid release of energy during microdamage events. DIC showed significant differences in anteromedial cortical strain between implants at 1500N and 2500N in the proximal 10mm only (p<0.001) with strain shielding in metal backed implants. AE showed significant differences in cancellous microdamage (AE hits), between implants at all loads (p=0.001). FB-AP implants displayed significantly more hits at all loads than both controls and metal backed implants (p<0.001). FB-AP implants also differed significantly by displaying AE hits on unloading (p=0.01), reflecting a lack of implant stiffness. Compared to controls, the FB-AP implant displayed 15x the total AE hits, the FB-MB 6x and the MB-MB 2.7x. All-polyethylene medial UKR implants are associated with greater cancellous bone microdamage than metal backed implants even at low loads

25–40% of unicompartmental knee replacement (UKR) revisions are performed for unexplained pain possibly secondary to elevated proximal tibial bone strain. This study investigates the effect of tibial component metal backing and polyethylene thickness on cancellous bone strain in a finite element model (FEM) of a cemented fixed bearing medial UKR, validated using previously published acoustic emission data (AE). FEMs of composite tibiae implanted with an all-polyethylene tibial component (AP) and a metal backed one (MB) were created. Polyethylene of thickness 6–10mm in 2mm increments was loaded to a medial load of 2500N. The volume of cancellous bone exposed to <−3000 (pathological overloading) and <−7000 (failure limit) minimum principal (compressive) microstrain (µ∊) and >3000 and >7000 maximum principal (tensile) microstrain was measured. Linear regression analysis showed good correlation between measured AE hits and volume of cancellous bone elements with compressive strain <−3000µ∊: correlation coefficients (R= 0.947, R2 = 0.847), standard error of the estimate (12.6 AE hits) and percentage error (12.5%) (p<0.001). AP implants displayed greater cancellous bone strains than MB implants for all strain variables at all loads. Patterns of strain differed between implants: MB concentrations at the lateral edge; AP concentrations at the keel, peg and at the region of load application. AP implants had 2.2 (10mm) to 3.2 (6mm) times the volume of cancellous bone compressively strained <−7000µ∊ than the MB implants. Altering MB polyethylene insert thickness had no effect. We advocate using caution with all-polyethylene UKR implants especially in large or active patients where loads are higher

Aims. To evaluate the outcomes of cemented total hip arthroplasty (THA) following a fracture of the acetabulum, with evaluation of risk factors and comparison with a patient group with no history of fracture. . Patients and Methods. Between 1992 and 2016, 49 patients (33 male) with mean age of 57 years (25 to 87) underwent cemented THA at a mean of 6.5 years (0.1 to 25) following acetabular fracture. A total of 38 had undergone surgical fixation and 11 had been treated non-operatively; 13 patients died at a mean of 10.2 years after THA (0.6 to 19). Patients were assessed pre-operatively, at one year and at final follow-up (mean 9.1 years, 0.5 to 23) using the Oxford Hip Score (OHS). Implant survivorship was assessed. An age and gender-matched cohort of THAs performed for non-traumatic osteoarthritis (OA) or avascular necrosis (AVN) (n = 98) were used to compare complications and patient-reported outcome measures (PROMs). Results. The mean time from fracture to THA was significantly shorter for patients with AVN (2.2 years) or protrusio (2.2 years) than those with post-traumatic OA (9.4 years) or infection (8.0 years) (p = 0.03). Nine contained and four uncontained defects were managed with autograft (n = 11), bulk allograft (n = 1), or trabecular metal augment (n = 1). Initial fracture management (open reduction and internal fixation or non-operative), timing of THA (> /< one year), and age (> /< 55 years) had no significant effect on OHS or ten-year survival. Six THAs were revised at mean of 12 years (5 to 23) with ten-year all-cause survival of 92% (95% confidence interval 80.8 to 100). THA complication rates (all complications, heterotopic ossification, leg length discrepancy > 10 mm) were significantly higher following acetabular fracture compared with atraumatic OA/AVN and OHSs were inferior: one-year OHS (35.7 versus 40.2, p = 0.026); and final follow-up OHS (33.6 versus 40.9, p = 0.008). . Conclusion . Cemented THA is a reasonable option for the sequelae of acetabular fracture. Higher complication rates and poorer PROMs, compared with patients undergoing THA for atraumatic causes, reflects the complex nature of these cases. Cite this article: Bone Joint J 2017;99-B:1399–1408

Introduction. Metal-on-metal (MoM) articulations in total hip replacement (THR) have become an attractive option for young, active patients. Short-term reports have demonstrated elevated systemic metal ion levels in the blood and urine. Disseminated concentrations of cobalt and chromium have raised concern regarding cellular toxicity, chromosomal damage and adverse local soft tissue reactions. Long-term studies are required to support the increased use of MoM bearings in younger patients given their potential deleterious effects. The purpose of the current study was to report the 7–13 year clinical, radiographic, and metal ion results in patients following MoM THR. Methods. We prospectively followed 165 patients (196 hips) after second-generation MoM THR between July 1997 and November 2003. Functional outcome was measured using the Harris Hip Score (HHS) and the University of California Los Angeles (UCLA) Activity Score. Radiographic analysis was performed using Einzel-Bild-Roentgen-Analyse (EBRA) by two of the authors blinded to the study. Cobalt and chromium metal ions were measured from whole blood and analyzed using inductively coupled plasma-mass spectrometry. Results. 163 prostheses were analyzed. The mean age at surgery was 50.8 years (range, 17 to 66). There were 80 females and 83 males. The mean follow-up was 8.87 years (range, 7–13 years). Four hips (2.5%) were revised: 2 for infection at 0.2 and 7 years; 1 for a loose stem at 1.3 years; and 1 for a loose cup at 9 years. One patient received wound debridement for a superficial infection and did not have any components revised. The mean HHS and UCLA scores at the last follow-up were 91 and 6.8, respectively. The mean acetabular inclination and anteversion was 40 degrees (range, 24 to 57), and 19 degrees (range, 3 to 39), respectively. Median cobalt levels peaked at a value of 2.87 μg/L at 4 years (p<0.0001 vs. pre-operative) and subsequently decreased to 2.0 μg/L after 9 years (p=0.002 vs. 4-years). Median chromium levels maximally increased up to 0.75 μg/L after 5 years (p<0.0001 vs. pre-operative) and tended to decrease thereafter to values of 0.56 μg/L after 7 years. The Kaplan-Meier survivorship was 91.3% for revision for all causes, and 97.5% when excluding the hips revised for a manufacturer's defect at a mean of 8.87 years (range, 7–13 years). Conclusion. The present 7–13 years follow-up study of MoM THRs indicates that the clinical and radiological results are satisfactory with low revision rates. Furthermore, our study demonstrates the trend of metal ion levels in whole blood over a long-term. Both cobalt and chromium ion levels peaked at 4 and 5 years, respectively, and gradually decreased thereafter

Aims

To explore staff experiences of a multicentre pilot randomized controlled trial (RCT) comparing intramedullary nails and circular frame external fixation for segmental tibial fractures.

Purpose. Angular deformity in the lower extremities can result in pain, gait disturbance, cosmetic deformity and joint degeneration. Up until the introduction of guided growth in 2007, which has since become the gold standard, treatment for correcting angular deformities in skeletally immature patients had been either an osteotomy, a hemiepiphysiodesis, or the use of staples. Methods. We reviewed the surgical records and diagnostic imaging in our childrens hospital to identify all patients who had guided growth surgery since 2007. All patients were followed until skeletal maturity or until their metalwork was removed. Results. 113 patients, with 147 legs were assessed for eligibility. Three were excluded for various reasons including inadequate follow-up or loss of records. Of the 144 treated legs which met the criteria for final assessment 32 (22.2%) were unsuccessful, the other 112 (77.8%) were deemed successful at final follow up. Complications were few, but included infection in one case and metal failure in another. Those with a pre-treatment diagnosis of idiopathic genu valgum/genu varum had a success rate of 83.6%. Conclusions. In our hands, guided growth had a seventy-eight percent success rate when all diagnosis were considered. Those procedures that were unlikely to be successful included growth disturbances due to mucopolysaccharide storage disease (28% failure rate), Blounts disease (66.6% failure rate) and achondroplasia (37.5% failure rate). If you exclude those three diagnoses, success rate for all other conditions was 81.4%. We continue to advocate the use of guided growth as a successful treatment option for skeletally immature patients with limb deformity

Aims

We report the long-term outcomes of the UK Heel Fracture Trial (HeFT), a pragmatic, multicentre, two-arm, assessor-blinded, randomized controlled trial.

Aims

Complex joint fractures of the lower extremity are often accompanied by soft-tissue swelling and are associated with prolonged hospitalization and soft-tissue complications. The aim of the study was to evaluate the effect of vascular impulse technology (VIT) on soft-tissue conditioning in comparison with conventional elevation.