High rate of tibial debonding and failure in a popular knee replacement : a follow-up review.

AIMS: Total knee arthroplasty (TKA) is a common and safe orthopaedic procedure. Zimmer Biomet's NexGen is the second most popular brand of implant used in the UK. The primary cause of revision after the first year is aseptic loosening. We present our experience of using this implant, with significant concerns around its performance with regards early aseptic loosening of the tibial component. METHODS: A retrospective, single-surgeon review was carried out of all of the NexGen Legacy Posterior Stabilized (LPS) TKAs performed in this institute. The specific model used for the index procedures was the NexGen Complete Knee System (Legacy Knee-Posterior Stabilized LPS-Flex Articular Surface, LPS-Flex Femoral Component Option, and Stemmed Nonaugmentable Tibial Component Option). RESULTS: Between 2013 and 2016, 352 NexGen TKAs were carried out on 331 patients. A total of 62 TKAs have been revised to date, giving an all-cause revision rate of 17.6% at a minimum of five years. Three of these revisions were due to infection. Overall, 59 of the revisions were performed for aseptic loosening (16.7%) of the tibial component. The tibial component was removed intraoperatively without instrumentation due to significant tibial debonding between the implant-cement interface. CONCLUSION: While overall, we believe that early aseptic loosening is multi-factorial in nature, the significantly high aseptic revision rate, as seen by an experienced fellowship-trained arthroplasty surgeon, has led us to believe that there is a fundamental issue with this NexGen implant design. Continued implant surveillance and rigorous review across all regions using this particular implant is warranted based on the concerning findings described here. Cite this article: Bone Jt Open 2022;3(6):495-501.

Thermal Expansion and Response to Pressure of Double-ReO3-Type Fluorides NaMVF6 (M = Nb, Ta).

Several II-IV double-ReO3-type (DROT) fluorides are known to exhibit strong negative thermal expansion (NTE) over a wide temperature range while retaining a cubic structure down to 120 K or lower. CaZrF6, CaNbF6, CaTiF6, and MgZrF6, embody these properties. In contrast to the behavior of these II-IV materials, the I-V DROT material, NaSbF6, has been reported to display a phase transition from rhombohedral to cubic above 300 K and positive thermal expansion both above and below the transition. In this work, NaNbF6 and NaTaF6 are shown to undergo first-order cubic-to-rhombohedral transitions on cooling to ∼130 K. Above this transition, NaNbF6 shows modest NTE between 160 and 250 K, whereas NaTaF6 exhibits near-zero thermal expansion over the range 210-270 K. These I-V systems are elastically softer than their II-IV counterparts, with a zero pressure bulk modulus, K0, of 14.6(8) GPa and first derivative of the bulk modulus with respect to pressure, K0', of -18(3) for cubic NaNbF6, and K0 = 14.47(3) GPa and K0'= -21.56(7) for cubic NaTaF6. When subject to ∼0.3 GPa at 300 K, both compounds exhibit a phase transition from Fm3̅m to R3̅. The R3̅ phases exhibit negative linear compressibility over a limited pressure range. A further transition with phase coexistence occurs at ∼2.5-3.0 GPa for NaNbF6 and ∼4.5 GPa for NaTaF6. Compression of NaNbF6 in helium at room temperature and below provides no evidence for helium penetration into the structure to form a perovskite with helium on the A-site, as was previously reported for CaZrF6.

High rate of tibial debonding and failure in a popular knee replacement: A cause for concern.

BACKGROUND: Total knee arthroplasty (TKA) is a common orthopedic procedure with 975,739 performed in the UK between 2003 and 2016. The two most common prosthetics used are P.F.C. Sigma and NexGen. The aim of this study is to compare the experience of a single fellowship-trained arthroplasty surgeon at a single dedicated orthopedic hospital using both of these prosthetics over a 17-year period. METHODS: This study was carried out as a retrospective review. Information was gathered from a database of primary TKAs and revision TKAs, as well as medical records, correspondence and operative notes. RESULTS: A total of 1,511 TKAs were performed between 1999 and 2015 - with a further follow-up period of 2 years. There were 1,161 consecutive P.F.C. primary TKAs done from 1999 to April 2013, after which, 350 consecutive NexGen primary TKAs were performed. Between 2015 and 2017, 26 NexGen revisions were required. 23 (6.6%) of the NexGen knees were carried out for aseptic loosening. The average time for revision from the NexGen index surgery was 30.4 months. The failures all presented similarly - with the tibial component having collapsed into varus and radiographic lucency noted under the implant. CONCLUSION: In spite of changes in orthopedic practice and advances in implant technology over the time period of this study, we would not expect this level of implant failure from a surgeon who had no previous significant issues with aseptic loosening using a different prosthetic. Usage of the NexGen knee has been discontinued at this center.

Streptococcus gordonii-a rare cause of prosthetic joint infection in a total hip replacement.

A 69-year-old female with a history of bilateral total hip replacements presented with rigors, fever and sudden onset left groin pain. A pelvic X-ray showed well-fixed implants. Blood results revealed a leucocytosis (white cell count 22.3 × 109 l-1) and elevated C-reactive protein (211 mg/l). Ultrasound-guided aspiration of her left hip grew Streptococcus gordonii No source infection could be identified apart from a new chronic sinus infection in a left upper incisor. Following a discussion with the patient a 6-week course of intravenous ceftriaxone was started and was successful in normalizing her inflammatory markers. She was placed on long-term suppressive amoxicillin following this. Her suppressive antibiotic therapy was complicated by the development of a clostridium difficile infection and her antibiotics were changed to doxycycline. At 1-year follow-up, she was asymptomatic with no further episodes of groin pain or fever.

Uncemented total hip arthroplasty in osteoarthritis of hip secondary to low and high dislocated hips: A mid-term follow-up study.

BACKGROUND: Performing successful total hip replacement (THR) in dysplastic, subluxed, and dislocated hip is a challenging task. Here, we assessed midterm clinical and radiological outcomes of uncemented total hip arthroplasty in osteoarthritis (OA) of hip secondary to Hartofilakidis low and high-dislocated hips with a mean follow-up of 8.8 years. MATERIALS AND METHODS: A retrospective study of prospectively collected data was designed involving all consecutive patients who underwent uncemented THR for OA of hip secondary to developmental dysplasia of the hip and Grade II or Grade III Hartofilakidis classification. RESULTS: Thirty-two patients underwent 45 THR, with 23 Grade II (low dislocation) and 22 Grade III (high-dislocation) of Hartofilakidis classification. Thirteen patients had bilateral hip replacements, 19 patients had unilateral THR. There was highly statistically significant difference between preoperative and postoperative HHS and SF-36v2™ at each follow-up. Survivorship of original implant was 98.88% at a mean follow-up of 8.8 years. The mean improvement in leg length in this series was 3.6 cm (1.8-4.5, 95% confidence interval). No sciatic nerve or femoral nerve palsies were observed. CONCLUSIONS: Uncemented THR provides better function and quality of life. However, longer follow-up studies are needed to assess survivorship of uncemented THR in Hartofilakidis low and high-dislocations.

A comparison of acetabular impaction grafting and trabecular metal for revision arthroplasty.

BACKGROUND: Acetabular defect reconstruction in revision hip arthroplasty may be achieved with acetabular impaction bone grafting (AIBG) or porous trabecular metal (TM) implantation. We sought to compare clinical and radiological outcomes of both methods at a single institution. METHODS: 36 patients that were revised using AIBG and 17 patients that were revised with TM were retrospectively reviewed from local joint registry data. 82% of the TM group and 64% of the AIBG group were ≥ Paprosky 2c. Rerevision was considered failure. Radiographs demonstrating 5 mm of migration of femoral head and 5° of acetabular component inclination change were considered loose. RESULTS: Age at surgery was earlier in the AIBG group (median 68 years vs. 74 years). Median follow-up was 5.9 years for AIBG and 5.4 years for TM. Harris Hip Scores improved significantly for both groups (mean improvement: 32 vs. 31). There were 4 failures (11%) in the AIBG group and none in the TM group. 3 of the 4 AIBG failures occurred following second-stage revision for prosthetic joint infection. 4 (11%) and 2 (12%) hip reconstructions demonstrated radiological evidence of loosening in AIBG and TM groups respectively. CONCLUSIONS: AIBG and TM acetabular defect reconstructions achieve good clinical outcome but there is greater success with TM in higher grades of acetabular deficiency regardless of prior infection.

Synchronous quadriceps tendon rupture and unilateral ACL tear in a weightlifter, associated with anabolic steroid use.

Synchronous quadriceps tendon rupture is rare. A 29-year-old man, an amateur weight lifter, taking androgenic-anabolic steroids (AAS), developed sudden onset bilateral pain and swelling of his anterior thighs when attempting to squat 280 kg (620 lb). Examination revealed gross swelling superior to the patella and palpable gaps in both quadriceps tendons. He underwent successful operative repair. MRI revealed a partial tear of the anterior cruciate ligament (ACL) of the right knee. This was not reconstructed. Only a few case reports of the association between AAS and quadriceps rupture exist in the literature, with none to the best of our knowledge in the past 10 years. ACL rupture coexisting is very rare, with only two reported cases.

Atraumatic Fracture of a BIOLOX Delta Ceramic Femoral Head Articulating with a Polyethylene Liner: A Case Report.

CASE: We describe the case of a forty-one-year-old man who underwent total hip arthroplasty with a 32-mm BIOLOX delta ceramic head articulating with a polyethylene liner. The patient did not suffer any trauma postoperatively, and his only symptom was of a "clicking" noise from the operatively treated hip. At his six-week postoperative review, fracture of the femoral head was diagnosed. CONCLUSION: Fracture of a ceramic femoral head is a rare but catastrophic complication. This case report highlights the importance of vigilance on the part of the surgeon when reviewing patients after hip arthroplasty with ceramic-on-polyethylene bearing couples, even with limited symptoms associated with the hip and no reported trauma.

The significance of hand dominance in hip osteoarthritis.

OBJECTIVES: Hip arthroplasty registries, encompassing all-cause end-stage hip degeneration, have shown that slightly more right hip replacements are performed than left. Given that greater than 85% of individuals are right-handed, we sought to investigate the association between side of hand dominance and side of hip osteoarthritis. METHODS: This Level III observational study evaluated exclusively end-stage osteoarthritis of the hip, using 3 independent centres totalling 386 consecutive arthroplasty patients. Logistic regression was used as a statistical model. RESULTS: In total, 322 patients with hip osteoarthritis were included in the final analysis, including 146 (45.5%) women and 176 (54.5%) men, with a mean age of 68.1 years (SD = 9.5 years). There were 133 (41.2%) right, 73 (22.6%) left, and 116 (35.9%) bilateral hips where the contralateral side had been previously replaced. The proportion of individuals requiring unilateral hip arthroplasty on their dominant side was 67.4%. CONCLUSIONS: In the development of hip osteoarthritis, one is significantly more likely to require hip arthroplasty on their dominant side than in the contralateral hip. Assessment of hand dominance identifies cerebral laterality as a contributing factor in predisposing one's dominant side to hip osteoarthritis.

A commentary on the disparate perspectives of clinical microbiologists and surgeons: ad hoc antimicrobial use.

Prosthetic joints and other orthopedic implants have improved quality of life for patients world-wide and the use of such devices is increasing. However, while infection rates subsequent to associated surgery are relatively low (<3%), the consequences of incidence are considerable, encompassing morbidity (including amputation) and mortality in addition to significant social and economic costs. Emphasis, therefore, has been placed on mitigating microbial risk, with clinical microbiologists and surgeons utilizing rapidly evolving molecular laboratory techniques in detection and diagnosis of infection, which still occurs despite sophisticated patient management. Multidisciplinary approaches are regularly adopted to achieve this. In this commentary, we describe an unusual case of Actinomyces infection in total hip arthroplasty and, in that context, describe the perspectives of the clinical microbiology and surgical teams and how they contrasted. More specifically, this case demonstrates an ad hoc approach to structured eradication of biofilms and intracellular bacteria related to biomaterials, as reflected in early usage of linezolid. This is a complex topic and, as described in this case, such accelerated treatment can be effective. This commentary focuses on the merits of such inadvisable use of potent antimicrobials amid the risk of diminishing valuable antimicrobial efficacy, albeit resulting in desirable patient outcomes.

A commentary on the disparate perspectives of clinical microbiologists and surgeons: Ad hoc antimicrobial use.

Prosthetic joints and other orthopedic implants have improved quality of life for patients world-wide and the use of such devices is increasing. However, while infection rates subsequent to associated surgery are relatively low (<3%), the consequences of incidence are considerable, encompassing morbidity (including amputation) and mortality in addition to significant social and economic costs. Emphasis, therefore, has been placed on mitigating microbial risk, with clinical microbiologists and surgeons utilizing rapidly evolving molecular laboratory techniques in detection and diagnosis of infection, which still occurs despite sophisticated patient management. Multidisciplinary approaches are regularly adopted to achieve this. In this commentary, we describe an unusual case of Actinomyces infection in total hip arthroplasty and, in that context, describe the perspectives of the clinical microbiology and surgical teams and how they contrasted. More specifically, this case demonstrates an ad hoc approach to structured eradication of biofilms and intracellular bacteria related to biomaterials, as reflected in early usage of linezolid. This is a complex topic and, as described in this case, such accelerated treatment can be effective. This commentary focuses on the merits of such inadvisable use of potent antimicrobials amid the risk of diminishing valuable antimicrobial efficacy, albeit resulting in desirable patient outcomes.

Surgeon delivered psoas compartment block in total hip arthroplasty.

Total hip arthroplasty is associated with significant postoperative pain. A psoas compartment block is superior to other regional techniques in analgesia post THA. However, traditional methods of delivery are associated with serious complications. We present a technique of a surgeon delivered lumbar plexus block through injection at the portion of the iliopsoas seen intraoperatively. We randomised fifty-three consecutive patients into two groups. The group that received the block had an increased period prior to requesting supplementary analgesia and lower overall pain scores. There were no adverse effects. We have demonstrated the analgesic efficacy of Psoas Compartment Block performed during surgical access for total hip arthroplasty. This technique should be considered in the analgesic regimen for total hip arthroplasty.

Haemodynamic performance of neuromuscular electrical stimulation (NMES) during recovery from total hip arthroplasty.

BACKGROUND: Patients post total hip arthroplasty (THA) remain at high risk of developing Deep Vein Thrombosis (DVT) during the recovery period following surgery despite the availability of effective pharmacological and mechanical prophylactic methods. The use of calf muscle neuromuscular electrical stimulation (NMES) during the hospitalised recovery period on this patient group may be effective at preventing DVT. However, the haemodynamic effectiveness and comfort characteristics of NMES in post-THA patients immediately following surgery have yet to be established. METHODS: The popliteal veins of 11 patients, who had undergone unilateral total hip replacement surgery on the day previous to the study, were measured using Doppler ultrasound during a 4 hour neuromuscular electrical stimulation (NMES) session of the calf muscles. The effect of calf muscle NMES on peak venous velocity, mean venous velocity and volume flow were compared to resting values. Comfort was assessed using a 100mm non-hatched visual analogue scale taken before application of NMES, once NMES was initiated and before NMES was withdrawn. RESULTS: In the operated limb NMES produced increases in peak venous velocity of 99% compared to resting. Mean velocity increased by 178% compared to resting and volume flow increased by 159% compared to resting. In the un-operated limb, peak venous velocity increased by 288%, mean velocity increased by 354% and volume flow increased by 614% compared to basal flow (p<0.05 in all cases). There were no significant differences observed between the VAS scores taken before the application of NMES, once NMES was initiated and before NMES was withdrawn (p=.211). CONCLUSIONS: NMES produces a beneficial hemodynamic response in patients in the early post-operative period following orthopaedic surgery. This patient group found extended periods of calf-muscle NMES tolerable. TRIAL REGISTRATION: ClinicalTrials.gov NCT01785251.

Optimizing the fat and water content of impaction bone allograft.

Fresh morselized impacted bone graft usually fails due to shear forces. The presence of fat, water, and marrow particles act as interparticle lubricants, reducing the interlocking of particles and allowing the graft to move more freely. Furthermore, the presence of this incompressible fluid damps and resists compressive forces during impaction, preventing the graft particles from moving into a closer formation. We believe there exists an ideal concentration of fat and water that will maximize resistance to shear forces. We performed mechanical shear testing in vitro on morselized human femoral heads, varying the amount of fat and water to determine their optimum concentrations. Level of fat and water were determined that increased strength by 36% over unaltered bone graft. This is most closely approximated in an operating room by washing and subsequently squeezing the bone graft. Optimizing the fat and water content of bone graft produces a stronger graft that is more resistant to shear stresses, protecting the surgical construct until bone growth can occur.

Another string.... but no bow.

Based on a positive personal experience, the authors advocate the use of a wound protector/retractor such as the Alexis system in total hip arthroplasty, to avoid intra-operative bacterial contamination from the skin, while avoiding damage to the skin and other soft tissues.

A cadaveric study of injectate spread in the psoas compartment with a direct iliopsoas injection suggested for use during surgery.

Total hip replacement produces significant postoperative pain. Psoas compartment block is the most effective block of the lumbar plexus in terms of pain relief and reduced blood loss. It is a proven regional technique for analgesia and anaesthesia during and after total hip replacement conferring a number of benefits to the patient. However, traditional techniques used to produce this block require increased theatre time and are associated with a number of serious complications. We present a surgeon-delivered technique for producing a lumbar plexus block using direct injection into the iliopsoas muscle when it is visible intraoperatively. This study shows a cadaveric model using methylene blue and radiopaque contrast produces injectate spread in a fashion which would produce a successful lumbar plexus block. This novel technique for lumbar plexus block affords the benefits of psoas compartment block with reduced complications and reduced administration time.

Infection of a total hip arthroplasty with actinomyces israelii: Report of a case.

CONTEXT: Infection of following total hip arthroplasties can be classified based on the timing of infection. Late infections with Actinomyces israelii are extremely rare with only 3 previously reported cases in literature. We present another case of a late infection with Actinomyces israelii in a total hip arthroplasty 9 years following implantation. CASE REPORT: A 71-year-old male with diabetes mellitus presented with right hip pain 9 years following a total hip arthroplasty. Physical examination revealed localised pain and biochemical investigations showed elevated inflammatory markers. X-rays were suspicious for infection and a collection around the prosthesis was confirmed by MRI scan. The patient underwent debridement and removal of prosthesis. Peri-operative specimen cultures isolated Actinomyces israelii. The patient responded to a combination of vancomycin followed by ciprofloxacin and linezolid therapy before undergoing a successful second-stage reimplantation surgery. CONCLUSION: This is the first reported case of late haematogenous infection by Actinomyces israelii in a total hip arthroplasty in a patient with diabetes mellitus as the only risk factor. The patient was successfully treated with antibiotic therapy and two-stage reimplantation arthroplasty.

Hemodynamic performance of NMES in the early post operative period following orthopaedic surgery.

Patients post total hip arthroplasty (THA) remain at high risk of developing Deep Vein Thrombosis (DVT) during the recovery period following surgery. The use of calf muscle neuromuscular electrical stimulation (NMES) during the hospitalized recovery period on this patient group may be effective at preventing DVT. However, the haemodynamic effectiveness and comfort characteristics of NMES in post-THA patients immediately following surgery has yet to be demonstrated. The popliteal veins of 5 patients, who had undergone unilateral total hip replacement surgery on the day previous to the study, were measured using Doppler ultrasound during a 4 hour calf-muscle NMES session. The effect of calf muscle NMES on peak venous velocity and volume flow were compared to resting values. Comfort was assessed using a 100 mm non-hatched visual analogue scale taken before application of NMES, once NMES was initiated and before NMES was withdrawn. Results of the study showed that NMES produces a beneficial hemodynamic response in patients in the early postoperative period following orthopaedic surgery. This patient group found extended periods of calf-muscle NMES tolerable.

Two-stage revision of infected hip arthroplasty using a shortened post-operative course of antibiotics.

INTRODUCTION: We present a series of 30 consecutive patients with 31 infected total hip arthroplasties treated by a single surgeon over a 4-year period in whom a shortened post-operative course of antimicrobial chemotherapy was used. METHODS: The treatment protocol consisted of a two-stage exchange with removal of infected components, insertion of an interim antibiotic eluting cement spacer and re-implantation of an extensively coated uncemented prosthesis on the femoral side. Systemic antibiotic treatment following each stage consisted of an abridged course of 5 days post-operative intra-venous administration followed by complete cessation of anti-microbial therapy. RESULTS: At a mean follow-up of 35 months (minimum 24 months), there were no cases of recurrent prosthetic infection and no patient had required revision for aseptic loosening or mechanical instability on the femoral side. The combination of effective-staged surgical joint debridement, a shortened post-operative course of systemic antibiotic treatment and an adequate latent period before re-implantation has led to encourage early results in this series of revised chronic hip joint prosthetic infections.

The 22-mm vs the 32-mm femoral head in cemented primary hip arthroplasty long-term clinical and radiological follow-up study.

A retrospective clinical and radiological analysis was performed on 117 patients (138 hips) with a mean age of 75 years and a mean follow-up of 11 years. The prostheses used were 2 similar monoblock femoral components with 22- and 32-mm head sizes; their effects on the wear of the high-density polyethylene cup were studied. Wear of component was determined by evaluating the standardized initial and follow-up radiographs. The mean rate of linear wear was higher in the 22-mm femoral head, whereas the volumetric wear was higher in the 32-mm femoral head. In both groups, volumetric wear was significantly correlated with cup lysis. Increasing body weight in both groups was associated with more volumetric wear. The radiological evidence of prosthetic loosening did not correlate well with clinical evaluation of the hip.