Aims. Poly(methyl methacrylate) (PMMA)-based bone cements are the industry standard in orthopaedics. PMMA cement has inherent disadvantages, which has led to the development and evaluation of a novel silorane-based biomaterial (SBB) for use as an orthopaedic cement. In this study we test both elution and mechanical properties of both PMMA and SBB, with and without antibiotic loading. Methods. For each cement (PMMA or SBB), three formulations were prepared (rifampin-added, vancomycin-added, and control) and made into pellets (6 mm × 12 mm) for testing. Antibiotic elution into phosphate-buffered saline was measured over 14 days. Compressive strength and modulus of all cement pellets were tested over 14 days. Results. The SBB cement was able to deliver rifampin over 14 days, while PMMA was unable to do so. SBB released more vancomycin overall than did PMMA. The mechanical properties of PMMA were significantly reduced upon rifampin incorporation, while there was no effect to the SBB cement. Vancomycin incorporation had no effect on the strength of either cement. Conclusion. SBB was found to be superior in terms of rifampin and vancomycin elution. Additionally, the incorporation of these antibiotics into SBB did not reduce the strength of the resultant SBB cement composite whereas rifampin substantially attenuates the strength of PMMA. Thus, SBB emerges as a potential weight-bearing alternative to PMMA for the local delivery of antibiotics. Cite this article: Bone Joint Res 2021;10(4):277–284

Objective. The objective of this study was to evaluate the rotation and translation of each joint in the hindfoot and compare the load response in healthy feet with that in stage II posterior tibial tendon dysfunction (PTTD) flatfoot by analysing the reconstructive three-dimensional (3D) computed tomography (CT) image data during simulated weight-bearing. . Methods. CT scans of 15 healthy feet and 15 feet with stage II PTTD flatfoot were taken first in a non-weight-bearing condition, followed by a simulated full-body weight-bearing condition. The images of the hindfoot bones were reconstructed into 3D models. The ‘twice registration’ method in three planes was used to calculate the position of the talus relative to the calcaneus in the talocalcaneal joint, the navicular relative to the talus in talonavicular joint, and the cuboid relative to the calcaneus in the calcaneocuboid joint. Results. From non- to full-body-weight-bearing condition, the difference in the talus position relative to the calcaneus in the talocalcaneal joint was 0.6° more dorsiflexed (p = 0.032), 1.4° more everted (p = 0.026), 0.9 mm more anterior (p = 0.031) and 1.0 mm more proximal (p = 0.004) in stage II PTTD flatfoot compared with that in a healthy foot. The navicular position difference relative to the talus in the talonavicular joint was 3° more everted (p = 0.012), 1.3 mm more lateral (p = 0.024), 0.8 mm more anterior (p = 0.037) and 2.1 mm more proximal (p = 0.017). The cuboid position difference relative to the calcaneus in the calcaneocuboid joint did not change significantly in rotation and translation (all p ≥ 0.08). . Conclusion. Referring to a previous study regarding both the cadaveric foot and the live foot, joint instability occurred in the hindfoot in simulated weight-bearing condition in patients with stage II PTTD flatfoot. The method used in this study might be applied to clinical analysis of the aetiology and evolution of PTTD flatfoot, and may inform biomechanical analyses of the effects of foot surgery in the future. Cite this article: Bone Joint Res 2013;2:255–63

Objectives. The lack of effective treatment for cartilage defects has prompted investigations using tissue engineering techniques for their regeneration and repair. The success of tissue-engineered repair of cartilage may depend on the rapid and efficient adhesion of transplanted cells to a scaffold. Our aim in this study was to repair full-thickness defects in articular cartilage in the weight-bearing area of a porcine model, and to investigate whether the CD44 monoclonal antibody biotin-avidin (CBA) binding technique could provide satisfactory tissue-engineered cartilage. Methods. Cartilage defects were created in the load-bearing region of the lateral femoral condyle of mini-type pigs. The defects were repaired with traditional tissue-engineered cartilage, tissue-engineered cartilage constructed with the biotin-avidin (BA) technique, tissue-engineered cartilage constructed with the CBA technique and with autologous cartilage. The biomechanical properties, Western blot assay, histological findings and immunohistochemical staining were explored. Results. The CBA group showed similar results to the autologous group in biomechanical properties, Moran’s criteria, histological tests and Wakitani histological scoring. Conclusions. These results suggest that tissue-engineered cartilage constructed using the CBA technique could be used effectively to repair cartilage defects in the weight-bearing area of joints. Cite this article: H. Lin, J. Zhou, L. Cao, H. R. Wang, J. Dong, Z. R. Chen. Tissue-engineered cartilage constructed by a biotin-conjugated anti-CD44 avidin binding technique for the repairing of cartilage defects in the weight-bearing area of knee joints in pigs. Bone Joint Res 2017;6:–295. DOI: 10.1302/2046-3758.65.BJR-2016-0277

Aims

This study investigates the effects of intra-articular injection of adipose-derived mesenchymal stem cells (AdMSCs) and platelet-rich plasma (PRP) on lameness, pain, and quality of life in osteoarthritic canine patients.

Aims. To evaluate inducing osteoarthritis (OA) by surgical destabilization of the medial meniscus (DMM) in mice with and without a stereomicroscope. Methods. Based on sample size calculation, 70 male C57BL/6 mice were randomly assigned to three surgery groups: DMM aided by a stereomicroscope; DMM by naked eye; or sham surgery. The group information was blinded to researchers. Mice underwent static weightbearing, von Frey test, and gait analysis at two-week intervals from eight to 16 weeks after surgery. Histological grade of OA was determined with the Osteoarthritis Research Society International (OARSI) scoring system. Results. Surgical DMM with or without stereomicroscope led to decrease in the mean of weightbearing percentages (-20.64% vs -21.44%, p = 0.792) and paw withdrawal response thresholds (-21.35% vs -24.65%, p = 0.327) of the hind limbs. However, the coefficient of variation (CV) of weight-bearing percentages and paw withdrawal response thresholds in naked-eye group were significantly greater than that in the microscope group (19.82% vs 6.94%, p < 0.001; 21.85% vs 9.86%, p < 0.001). The gait analysis showed a similar pattern. Cartilage degeneration was observed in both DMM-surgery groups, evidenced by increased OARSI scores (summed score: 11.23 vs 11.43, p = 0.842), but the microscope group showed less variation in OARSI score than the naked-eye group (CV: 21.03% vs 32.44%; p = 0.032). Conclusion. Although surgical DMM aided by stereomicroscope is technically difficult, it produces a relatively more homogeneous OA model in terms of the discrete degree of pain behaviours and histopathological grading when compared with surgical DMM without stereomicroscope. Cite this article: Bone Joint Res 2022;11(8):518–527

Aims. Poly (ADP-ribose) polymerase (PARP) inhibitor has been reported to attenuate inflammatory response in rat models of inflammation. This study was designed to investigate the effect of PARP signalling in osteoarthritis (OA) cartilage inflammatory response in an OA rat model. Methods. The OA model was established by anterior cruciate ligament transection with medial meniscectomy in Wistar rats. The poly (ADP-ribose) polymerase 1 (PARP-1) shRNA (short hairpin (sh)-PARP-1) and negative control shRNA (sh-NC) were delivered using a lentiviral vector and were intra-articularly injected into rats after surgery. The weight-bearing distribution of the hind limbs and the knee joint width were measured every two weeks. The expression levels of PARP-1, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) in cartilage were determined using real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) and Western blot. The serum concentrations of inflammatory cytokines were detected using enzyme-linked immunosorbent assay (ELISA). Results. PARP-1 expression level significantly increased in the cartilage of the established OA rat model. sh-PARP-1 treatment suppressed PARP-1 levels, decreased the Δ Force (the difference between the weight on ipsilateral limb and contralateral limb) and the knee joint width, inhibited cartilage matrix catabolic enzymes, and ameliorated OA cartilage degradation and attenuated inflammatory response. Conclusion. PARP-1 inhibition attenuates OA cartilage inflammatory response in the OA rat model. Cite this article: Bone Joint Res 2021;10(7):401–410

Aims. This study aims to investigate the effects of posterior tibial slope (PTS) on knee kinematics involved in the post-cam mechanism in bi-cruciate stabilized (BCS) total knee arthroplasty (TKA) using computer simulation. Methods. In total, 11 different PTS (0° to 10°) values were simulated to evaluate the effect of PTS on anterior post-cam contact conditions and knee kinematics in BCS TKA during weight-bearing stair climbing (from 86° to 6° of knee flexion). Knee kinematics were expressed as the lowest points of the medial and lateral femoral condyles on the surface of the tibial insert, and the anteroposterior translation of the femoral component relative to the tibial insert. Results. Anterior post-cam contact in BCS TKA was observed with the knee near full extension if PTS was 6° or more. BCS TKA showed a bicondylar roll forward movement from 86° to mid-flexion, and two different patterns from mid-flexion to knee extension: screw home movement without anterior post-cam contact and bicondylar roll forward movement after anterior post-cam contact. Knee kinematics in the simulation showed similar trends to the clinical in vivo data and were almost within the range of inter-specimen variability. Conclusion. Postoperative knee kinematics in BCS TKA differed according to PTS and anterior post-cam contact; in particular, anterior post-cam contact changed knee kinematics, which may affect the patient’s perception of the knee during activities. Cite this article: Bone Joint Res 2020;9(11):761–767

Objectives. The objective of this study was to characterize the effect of rifampin incorporation into poly(methyl methacrylate) (PMMA) bone cement. While incompatibilities between the two materials have been previously noted, we sought to identify and quantify the cause of rifampin’s effects, including alterations in curing properties, mechanical strength, and residual monomer content. Methods. Four cement groups were prepared using commercial PMMA bone cement: a control; one with 1 g of rifampin; and one each with equimolar amounts of ascorbic acid or hydroquinone relative to the amount of rifampin added. The handling properties, setting time, exothermic output, and monomer loss were measured throughout curing. The mechanical strength of each group was tested over 14 days. A radical scavenging assay was used to assess the scavenging abilities of rifampin and its individual moieties. Results. Compared with control, the rifampin-incorporated cement had a prolonged setting time and a reduction in exothermic output during polymerization. The rifampin cement showed significantly reduced strength and was below the orthopaedic weight-bearing threshold of 70 MPa. Based on the radical scavenging assay and strength tests, the hydroquinone structure within rifampin was identified as the polymerization inhibitor. Conclusion. The incorporation of rifampin into PMMA bone cement interferes with the cement’s radical polymerization. This interference is due to the hydroquinone moiety within rifampin. This combination alters the cement’s handling and curing properties, and lowers the strength below the threshold for weight-bearing applications. Additionally, the incomplete polymerization leads to increased toxic monomer output, which discourages its use even in non-weight-bearing applications. Cite this article: G. A. Funk, E. M. Menuey, K. A. Cole, T. P. Schuman, K. V. Kilway, T. E. McIff. Radical scavenging of poly(methyl methacrylate) bone cement by rifampin and clinically relevant properties of the rifampin-loaded cement. Bone Joint Res 2019;8:81–89. DOI: 10.1302/2046-3758.82.BJR-2018-0170.R2

Aims. Evaluate if treating an unstable femoral neck fracture with a locking plate and spring-loaded telescoping screw system would improve construct stability compared to gold standard treatment methods. Methods. A 31B2 Pauwels’ type III osteotomy with additional posterior wedge was cut into 30 fresh-frozen femur cadavers implanted with either: three cannulated screws in an inverted triangle configuration (CS), a sliding hip screw and anti-rotation screw (SHS), or a locking plate system with spring-loaded telescoping screws (LP). Dynamic cyclic compressive testing representative of walking with increasing weight-bearing was applied until failure was observed. Loss of fracture reduction was recorded using a high-resolution optical motion tracking system. Results. LP constructs demonstrated the highest mean values for initial stiffness and failure load. LP and SHS constructs survived on mean over 50% more cycles and to loads 450 N higher than CS. During the early stages of cyclic loading, mean varus collapse of the femoral head was 0.5° (SD 0.8°) for LP, 0.7° (SD 0.7°) for SHS, and 1.9° (SD 2.3°) for CS (p = 0.071). At 30,000 cycles (1,050 N) mean femoral neck shortening was 1.8 mm (SD 1.9) for LP, 2.0 mm (SD 0.9) for SHS, and 3.2 mm (SD 2.5) for CS (p = 0.262). Mean leg shortening at construct failure was 4.9 mm (SD 2.7) for LP, 8.9 mm (SD 3.2) for SHS, and 7.0 mm (SD 4.3) for CS (p = 0.046). Conclusion. Use of the LP system provided similar (hip screw) or better (cannulated screws) biomechanical performance as the current gold standard methods suggesting that the LP system could be a promising alternative for the treatment of unstable fractures of the femoral neck. Cite this article: Bone Joint Res 2020;9(6):314–321

Objectives. The aim of this study was to determine the polyethylene wear rate of Phase 3 Oxford Unicompartmental Knee Replacement bearings and to investigate the effects of resin type and manufacturing process. Methods. A total of 63 patients with at least ten years’ follow-up with three bearing types (1900 resin machined, 1050 resin machined, and 1050 resin moulded) were recruited. Patients underwent full weight-bearing model-based radiostereometric analysis to determine the bearing thickness. The linear wear rate was estimated from the change in thickness divided by the duration of implantation. Results. The wear rate for 1900 resin machined (n = 19), 1050 machined (n = 21), and 1050 moulded bearings (n = 23) were 60 µm/year (. sd. 42), 76 µm/year (. sd. 32), and 57 µm/year (. sd. 30), respectively. There was no significant difference between 1900 machined and 1050 machined (p = 0.20), but 1050 moulded had significantly less wear than the 1050 machined (p = 0.05). Increasing femoral (p < 0.001) and tibial (p < 0.001) component size were associated with increasing wear. Conclusion. Wear rate is similar with 1050 and 1900 resin, but lower with moulded bearings than machined bearings. The currently used Phase 3 bearings wear rate is low (1050 moulded, 57 µm/year), but higher than the previously reported Phase 2 bearings (1900 moulded, 20 µm/year). This is unlikely to be due to the change in polyethylene but may relate to the minimally invasive approach used with the Phase 3. This approach, as well as improving function and thus increasing activity levels, may increase the risk of surgical errors, such as impingement or bearing overhang, which can increase wear. Surgeons should aim to use 4 mm thick bearings rather than 3 mm thick bearings in young patients, unless they are small and need conservative bone resections. Cite this article: Bone Joint Res 2019;8:535–543

Objectives. The incidence of acute Achilles tendon rupture appears to be increasing. The aim of this study was to summarize various therapies for acute Achilles tendon rupture and discuss their relative merits. Methods. A PubMed search about the management of acute Achilles tendon rupture was performed. The search was open for original manuscripts and review papers limited to publication from January 2006 to July 2017. A total of 489 papers were identified initially and finally 323 articles were suitable for this review. Results. The treatments of acute Achilles tendon rupture include operative and nonoperative treatments. Operative treatments mainly consist of open repair, percutaneous repair, mini-open repair, and augmentative repair. Traditional open repair has lower re-rupture rates with higher risks of complications. Percutaneous repair and mini-open repair show similar re-rupture rates but lower overall complication rates when compared with open repair. Percutaneous repair requires vigilance against nerve damage. Functional rehabilitation combining protected weight-bearing and early controlled motion can effectively reduce re-rupture rates with satisfactory outcomes. Biological adjuncts help accelerating tendon healing by adhering rupture ends or releasing highly complex pools of signalling factors. Conclusion. The optimum treatment for complete rupture remains controversial. Both mini-open repair and functional protocols are attractive alternatives, while biotherapy is a potential future development. Cite this article: X. Yang, H. Meng, Q. Quan, J. Peng, S. Lu, A. Wang. Management of acute Achilles tendon ruptures: A review. Bone Joint Res 2018;7:561–569. DOI: 10.1302/2046-3758.710.BJR-2018-0004.R2

Objectives. Unicompartmental knee arthroplasty (UKA) is one surgical option for treating symptomatic medial osteoarthritis. Clinical studies have shown the functional benefits of UKA; however, the optimal alignment of the tibial component is still debated. The purpose of this study was to evaluate the effects of tibial coronal and sagittal plane alignment in UKA on knee kinematics and cruciate ligament tension, using a musculoskeletal computer simulation. Methods. The tibial component was first aligned perpendicular to the mechanical axis of the tibia, with a 7° posterior slope (basic model). Subsequently, coronal and sagittal plane alignments were changed in a simulation programme. Kinematics and cruciate ligament tensions were simulated during weight-bearing deep knee bend and gait motions. Translation was defined as the distance between the most medial and the most lateral femoral positions throughout the cycle. Results. The femur was positioned more medially relative to the tibia, with increasing varus alignment of the tibial component. Medial/lateral (ML) translation was smallest in the 2° varus model. A greater posterior slope posteriorized the medial condyle and increased anterior cruciate ligament (ACL) tension. ML translation was increased in the > 7° posterior slope model and the 0° model. Conclusion. The current study suggests that the preferred tibial component alignment is between neutral and 2° varus in the coronal plane, and between 3° and 7° posterior slope in the sagittal plane. Varus > 4° or valgus alignment and excessive posterior slope caused excessive ML translation, which could be related to feelings of instability and could potentially have negative effects on clinical outcomes and implant durability. Cite this article: K. Sekiguchi, S. Nakamura, S. Kuriyama, K. Nishitani, H. Ito, Y. Tanaka, M. Watanabe, S. Matsuda. Bone Joint Res 2019;8:126–135. DOI: 10.1302/2046-3758.83.BJR-2018-0208.R2

Objectives. The medially spherical GMK Sphere (Medacta International AG, Castel San Pietro, Switzerland) total knee arthroplasty (TKA) was previously shown to accommodate lateral rollback while pivoting around a stable medial compartment, aiming to replicate native knee kinematics in which some coronal laxity, especially laterally, is also present. We assess coronal plane kinematics of the GMK Sphere and explore the occurrence and pattern of articular separation during static and dynamic activities. Methods. Using pulsed fluoroscopy and image matching, the coronal kinematics and articular surface separation of 16 well-functioning TKAs were studied during weight-bearing and non-weight-bearing, static, and dynamic activities. The closest distances between the modelled articular surfaces were examined with respect to knee position, and proportions of joint poses exhibiting separation were computed. Results. Overall, 1717 joint poses were analyzed. At a 1.0 mm detection threshold, 37 instances of surface separation were observed in the lateral compartment and four medially (p < 0.001). Separation was activity-dependent, both laterally and medially (p < 0.001), occurring more commonly during static deep flexion in the lateral compartment, and during static rotation in the medial compartment. Lateral separation occurred more frequently than medial during kneeling (7/14 lateral vs 1/14 medial; p = 0.031) and stepping (20/1022 lateral vs 0/1022 medial; p < 0.001). Separation varied significantly between individuals during dynamic activities. Conclusion. No consistent association between closest distances of the articular surfaces and knee position was found during any activity. Lift-off was infrequent and depended on the activity performed and the individual knee. Lateral separation was consistent with the design rationale. Medial lift-off was rare and mostly in non-weight-bearing activities. Cite this article: S. Key, G. Scott, J. G. Stammers, M. A. R. Freeman†, V. Pinskerova, R. E. Field, J. Skinner, S. A. Banks. Does lateral lift-off occur in static and dynamic activity in a medially spherical total knee arthroplasty? A pulsed-fluoroscopic investigation. Bone Joint Res 2019;8:207–215. DOI: 10.1302/2046-3758.85.BJR-2018-0237.R1

Objectives. Little is known about tissue changes underlying bone marrow lesions (BMLs) in non-weight-bearing joints with osteoarthritis (OA). Our aim was to characterize BMLs in OA of the hand using dynamic histomorphometry. We therefore quantified bone turnover and angiogenesis in subchondral bone at the base of the thumb, and compared the findings with control bone from hip OA. Methods. Patients with OA at the base of the thumb, or the hip, underwent preoperative MRI to assess BMLs, and tetracycline labelling to determine bone turnover. Three groups were compared: trapezium bones removed by trapeziectomy from patients with thumb base OA (n = 20); femoral heads with (n = 24); and those without (n = 9) BMLs obtained from patients with hip OA who underwent total hip arthroplasty. Results. All trapezium bones demonstrated MRI-defined BMLs. Compared with femoral heads without BMLs, the trapezia demonstrated significantly higher bone turnover (mean . sd. 0.2 (0.1) versus 0.01 (0.01) µm. 3. /µm. 2. /day), mineralizing surface (18.5% (13.1) versus 1.4% (1.3)) and vascularity (5.2% (1.1) versus 1.2% (0.6)). Femoral heads with BMLs exhibited higher bone turnover (0.3 (0.2) versus 0.2 (0.1) µm. 3. /µm. 2. /day), a higher mineralization rate (26.6% (10.6) versus 18.6% (11.9)) and greater trabecular thickness (301.3 µm (108) versus 163.6 µm (24.8)) than the trapezia. Conclusion. Bone turnover and angiogenesis were enhanced in BMLs of both the thumb base and hip OA, of which the latter exhibited the highest bone turnover. Thus, the increase in bone turnover in weight-bearing joints like the hip may be more pronounced than less mechanically loaded osteoarthritic joints demonstrating BMLs. The histological changes observed may explain the water signal from BMLs on MRI. Cite this article: M. Shabestari, N. J. Kise, M. A. Landin, S. Sesseng, J. C. Hellund, J. E. Reseland, E. F. Eriksen, I. K. Haugen. Enhanced angiogenesis and increased bone turnover characterize bone marrow lesions in osteoarthritis at the base of the thumb. Bone Joint Res 2018;7:406–413. DOI: 10.1302/2046-3758.76.BJR-2017-0083.R3

Osteoarthritis (OA) is mainly caused by ageing, strain, trauma, and congenital joint abnormalities, resulting in articular cartilage degeneration. During the pathogenesis of OA, the changes in subchondral bone (SB) are not only secondary manifestations of OA, but also an active part of the disease, and are closely associated with the severity of OA. In different stages of OA, there were microstructural changes in SB. Osteocytes, osteoblasts, and osteoclasts in SB are important in the pathogenesis of OA. The signal transduction mechanism in SB is necessary to maintain the balance of a stable phenotype, extracellular matrix (ECM) synthesis, and bone remodelling between articular cartilage and SB. An imbalance in signal transduction can lead to reduced cartilage quality and SB thickening, which leads to the progression of OA. By understanding changes in SB in OA, researchers are exploring drugs that can regulate these changes, which will help to provide new ideas for the treatment of OA.

Cite this article: Bone Joint Res 2023;12(9):536–545.

Aims

This study investigated the effects of β-caryophyllene (BCP) on protecting bone from vitamin D deficiency in mice fed on a diet either lacking (D-) or containing (D+) vitamin D.

Objectives. Subtotal or total meniscectomy in the medial or lateral compartment of the knee results in a high risk of future osteoarthritis. Meniscal allograft transplantation has been performed for over thirty years with the scientifically plausible hypothesis that it functions in a similar way to a native meniscus. It is thought that a meniscal allograft transplant has a chondroprotective effect, reducing symptoms and the long-term risk of osteoarthritis. However, this hypothesis has never been tested in a high-quality study on human participants. This study aims to address this shortfall by performing a pilot randomised controlled trial within the context of a comprehensive cohort study design. Methods. Patients will be randomised to receive either meniscal transplant or a non-operative, personalised knee therapy program. MRIs will be performed every four months for one year. The primary endpoint is the mean change in cartilage volume in the weight-bearing area of the knee at one year post intervention. Secondary outcome measures include the mean change in cartilage thickness, T2 maps, patient-reported outcome measures, health economics assessment and complications. Results. This study is expected to report its findings in 2016. Cite this article: Bone Joint Res 2015;4:93–8

Objectives. The evidence base to inform the management of Achilles tendon rupture is sparse. The objectives of this research were to establish what current practice is in the United Kingdom and explore clinicians’ views on proposed further research in this area. This study was registered with the ISRCTN (ISRCTN68273773) as part of a larger programme of research. Methods. We report an online survey of current practice in the United Kingdom, approved by the British Orthopaedic Foot and Ankle Society and completed by 181 of its members. A total of ten of these respondents were invited for a subsequent one-to-one interview to explore clinician views on proposed further research in this area. Results. The survey showed wide variations in practice, with patients being managed in plaster cast alone (13%), plaster cast followed by orthoses management (68%), and orthoses alone (19%). Within these categories, further variation existed regarding the individual rehabilitation facets, such as the length of time worn, the foot position within them and weight-bearing status. The subsequent interviews reflected this clinical uncertainty and the pressing need for definitive research. Conclusions. The gap in evidence in this area has resulted in practice in the United Kingdom becoming varied and based on individual opinion. Future high-quality randomised trials on this subject are supported by the clinical community. Cite this article: Bone Joint Res 2015;4:65–9

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To develop an early implant instability murine model and explore the use of intermittent parathyroid hormone (iPTH) treatment for initially unstable implants.

Objectives. Throughout the 20th Century, it has been postulated that the knee moves on the basis of a four-bar link mechanism composed of the cruciate ligaments, the femur and the tibia. As a consequence, the femur has been thought to roll back with flexion, and total knee arthroplasty (TKA) prostheses have been designed on this basis. Recent work, however, has proposed that at a position of between 0° and 120° the medial femoral condyle does not move anteroposteriorly whereas the lateral femoral condyle tends, but is not obliged, to roll back – a combination of movements which equates to tibial internal/ femoral external rotation with flexion. The aim of this paper was to assess if the articular geometry of the GMK Sphere TKA could recreate the natural knee movements in situ/in vivo. Methods. The pattern of knee movement was studied in 15 patients (six male: nine female; one male with bilateral TKAs) with 16 GMK Sphere implants, at a mean age of 66 years (53 to 76) with a mean BMI of 30 kg/m. 2. (20 to 35). The motions of all 16 knees were observed using pulsed fluoroscopy during a number of weight-bearing and non-weight-bearing static and dynamic activities. Results. During maximally flexed kneeling and lunging activities, the mean tibial internal rotation was 8° (standard deviation (. sd. ) 6). At a mean 112° flexion (. sd. 16) during lunging, the medial and lateral condyles were a mean of 2 mm (. sd. 3) and 8 mm (. sd. 4) posterior to a transverse line passing through the centre of the medial tibial concavity. With a mean flexion of 117° (. sd. 14) during kneeling, the medial and lateral condyles were a mean of 1 mm (. sd. 4) anterior and 6 mm (. sd. 4) posterior to the same line. During dynamic stair and pivoting activities, there was a mean anteroposterior translation of 0 mm to 2 mm of the medial femoral condyle. Backward lateral condylar translation occurred and was linearly related to tibial rotation. Conclusion. The GMK Sphere TKA in our study group shows movements similar in pattern, although reduced in magnitude, to those in recent reports relating to normal knees during several activities. Specifically, little or no translation of the medial femoral condyle was observed during flexion, but there was posterior roll-back of the lateral femoral condyle, equating to tibiofemoral rotation. We conclude that the GMK Sphere is anteroposteriorly stable medially and permits rotation about the medial compartment. Cite this article: Professor G. Scott. Can a total knee arthroplasty be both rotationally unconstrained and anteroposteriorly stabilised?: A pulsed fluoroscopic investigation. Bone Joint Res 2016;5:80–86. DOI: 10.1302/2046-3758.53.2000621

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The distal radius is a major site of osteoporotic bone loss resulting in a high risk of fragility fracture. This study evaluated the capability of a cortical index (CI) at the distal radius to predict the local bone mineral density (BMD).

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In contrast to operations performed for other fractures, there is a high incidence rate of surgical site infection (SSI) post-open reduction and internal fixation (ORIF) done for tibial plateau fractures (TPFs). This study investigates the effect of induced membrane technique combined with internal fixation for managing SSI in TPF patients who underwent ORIF.

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Acetabular edge-loading was a cause of increased wear rates in metal-on-metal hip arthroplasties, ultimately contributing to their failure. Although such wear patterns have been regularly reported in retrieval analyses, this study aimed to determine their in vivo location and investigate their relationship with acetabular component positioning.

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To explore the clinical relevance of joint space width (JSW) narrowing on standardized-flexion (SF) radiographs in the assessment of cartilage degeneration in specific subregions seen on MRI sequences in knee osteoarthritis (OA) with neutral, valgus, and varus alignments, and potential planning of partial knee arthroplasty.

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Circular RNAs (circRNAs) are a novel type of non-coding RNA that plays major roles in the development of diverse diseases including osteonecrosis of the femoral head (ONFH). Here, we explored the impact of hsa_circ_0066523 derived from forkhead box P1 (FOXP1) (also called circFOXP1) on bone mesenchymal stem cells (BMSCs), which is important for ONFH development.

As our understanding of hip function and disease improves, it is evident that the acetabular fossa has received little attention, despite it comprising over half of the acetabulum’s surface area and showing the first signs of degeneration. The fossa’s function is expected to be more than augmenting static stability with the ligamentum teres and being a templating landmark in arthroplasty. Indeed, the fossa, which is almost mature at 16 weeks of intrauterine development, plays a key role in hip development, enabling its nutrition through vascularization and synovial fluid, as well as the influx of chondrogenic stem/progenitor cells that build articular cartilage. The pulvinar, a fibrofatty tissue in the fossa, has the same developmental origin as the synovium and articular cartilage and is a biologically active area. Its unique anatomy allows for homogeneous distribution of the axial loads into the joint. It is composed of intra-articular adipose tissue (IAAT), which has adipocytes, fibroblasts, leucocytes, and abundant mast cells, which participate in the inflammatory cascade after an insult to the joint. Hence, the fossa and pulvinar should be considered in decision-making and surgical outcomes in hip preservation surgery, not only for their size, shape, and extent, but also for their biological capacity as a source of cytokines, immune cells, and chondrogenic stem cells.

Cite this article: Bone Joint Res 2020;9(12):857–869.

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The aim of this retrospective study was to determine if there are differences in short-term clinical outcomes among four different types of matrix-associated autologous chondrocyte transplantation (MACT).

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This study aims to enhance understanding of clinical and radiological consequences and involved mechanisms that led to corrosion of the Precice Stryde (Stryde) intramedullary lengthening nail in the post market surveillance era of the device. Between 2018 and 2021 more than 2,000 Stryde nails have been implanted worldwide. However, the outcome of treatment with the Stryde system is insufficiently reported.

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The value of core decompression (CD) in the treatment of osteonecrosis of the femoral head (ONFH) remains controversial. We conducted a systematic review and meta-analysis to evaluate whether CD combined with other treatments could improve the clinical and radiological outcomes of ONFH patients compared with CD alone.

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Non-coding microRNA (miRNA) in extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) may promote neuronal repair after spinal cord injury (SCI). In this paper we report on the effects of MSC-EV-microRNA-381 (miR-381) in a rodent model of SCI.

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There are concerns regarding initial stability and early periprosthetic fractures in cementless hip arthroplasty using short stems. This study aimed to investigate stress on the cortical bone around the stem and micromotions between the stem and cortical bone according to femoral stem length and positioning.

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In recent conflicts, most injuries to the limbs are due to blasts resulting in a large number of lower limb amputations. These lead to heterotopic ossification (HO), phantom limb pain (PLP), and functional deficit. The mechanism of blast loading produces a combined fracture and amputation. Therefore, to study these conditions, in vivo models that replicate this combined effect are required. The aim of this study is to develop a preclinical model of blast-induced lower limb amputation.

Aims

This study aimed to investigate whether human umbilical cord mesenchymal stem cells (UC-MSCs) can prevent articular cartilage degradation and explore the underlying mechanisms in a rat osteoarthritis (OA) model induced by monosodium iodoacetate (MIA).

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The present study investigates the effectiveness of platelet-rich plasma (PRP) gel without adjunct to induce cartilage regeneration in large osteochondral defects in a rabbit model.

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Osteoarthritis (OA) is a disabling joint disorder and mechanical loading is an important pathogenesis. This study aims to investigate the benefits of less mechanical loading created by intermittent tail suspension for knee OA.

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Vertebrates have adapted to life on Earth and its constant gravitational field, which exerts load on the body and influences the structure and function of tissues. While the effects of microgravity on muscle and bone homeostasis are well described, with sarcopenia and osteoporosis observed in astronauts returning from space, the effects of shorter exposures to increased gravitational fields are less well characterized. We aimed to test how hypergravity affects early cartilage and skeletal development in a zebrafish model.

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To evaluate graft healing of decellularized porcine superflexor tendon (pSFT) xenograft in an ovine anterior cruciate ligament (ACL) reconstruction model using two femoral fixation devices. Also, to determine if pSFT allows functional recovery of gait as compared with the preoperative measurements.

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Fibrinolysis plays a key transition step from haematoma formation to angiogenesis and fracture healing. Low-magnitude high-frequency vibration (LMHFV) is a non-invasive biophysical modality proven to enhance fibrinolytic factors. This study investigates the effect of LMHFV on fibrinolysis in a clinically relevant animal model to accelerate osteoporotic fracture healing.

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To explore the effect of different types of articulating antibiotic-loaded cement spacers in two-stage revision for chronic hip prosthetic joint infection (PJI).

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Restoration of proximal medial femoral support is the keystone in the treatment of intertrochanteric fractures. None of the available implants are effective in constructing the medial femoral support. Medial sustainable nail (MSN-II) is a novel cephalomedullary nail designed for this. In this study, biomechanical difference between MSN-II and proximal femoral nail anti-rotation (PFNA-II) was compared to determine whether or not MSN-II can effectively reconstruct the medial femoral support.

Bone is a dynamic tissue with a quarter of the trabecular and a fifth of the cortical bone being replaced continuously each year in a complex process that continues throughout an individual’s lifetime. Bone has an important role in homeostasis of minerals with non-stoichiometric hydroxyapatite bone mineral forming the inorganic phase of bone. Due to its crystal structure and chemistry, hydroxyapatite (HA) and related apatites have a remarkable ability to bind molecules. This review article describes the accretion of trace elements in bone mineral giving a historical perspective. Implanted HA particles of synthetic origin have proved to be an efficient recruiting moiety for systemically circulating drugs which can locally biomodulate the material and lead to a therapeutic effect. Bone mineral and apatite however also act as a waste dump for trace elements and drugs, which significantly affects the environment and human health.

Cite this article: Bone Joint Res 2020;9(10):709–718.

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The diversity of femoral morphology renders femoral component sizing in total hip arthroplasty (THA) challenging. We aimed to determine whether femoral morphology and femoral component filling influence early clinical and radiological outcomes following THA using fully hydroxyapatite (HA)-coated femoral components.

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In the context of tendon degenerative disorders, the need for innovative conservative treatments that can improve the intrinsic healing potential of tendon tissue is progressively increasing. In this study, the role of pulsed electromagnetic fields (PEMFs) in improving the tendon healing process was evaluated in a rat model of collagenase-induced Achilles tendinopathy.

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This study is a prospective, non-randomized trial for the treatment of fractures of the medial malleolus using lean, bioabsorbable, rare-earth element (REE)-free, magnesium (Mg)-based biodegradable screws in the adult skeleton.

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Extracellular matrix (ECM) and its architecture have a vital role in articular cartilage (AC) structure and function. We hypothesized that a multi-layered chitosan-gelatin (CG) scaffold that resembles ECM, as well as native collagen architecture of AC, will achieve superior chondrogenesis and AC regeneration. We also compared its in vitro and in vivo outcomes with randomly aligned CG scaffold.

The ability to edit DNA at the nucleotide level using clustered regularly interspaced short palindromic repeats (CRISPR) systems is a relatively new investigative tool that is revolutionizing the analysis of many aspects of human health and disease, including orthopaedic disease. CRISPR, adapted for mammalian cell genome editing from a bacterial defence system, has been shown to be a flexible, programmable, scalable, and easy-to-use gene editing tool. Recent improvements increase the functionality of CRISPR through the engineering of specific elements of CRISPR systems, the discovery of new, naturally occurring CRISPR molecules, and modifications that take CRISPR beyond gene editing to the regulation of gene transcription and the manipulation of RNA. Here, the basics of CRISPR genome editing will be reviewed, including a description of how it has transformed some aspects of molecular musculoskeletal research, and will conclude by speculating what the future holds for the use of CRISPR-related treatments and therapies in clinical orthopaedic practice.

Cite this article: Bone Joint Res 2020;9(7):351–359.

Bone is one of the most highly adaptive tissues in the body, possessing the capability to alter its morphology and function in response to stimuli in its surrounding environment. The ability of bone to sense and convert external mechanical stimuli into a biochemical response, which ultimately alters the phenotype and function of the cell, is described as mechanotransduction. This review aims to describe the fundamental physiology and biomechanisms that occur to induce osteogenic adaptation of a cell following application of a physical stimulus. Considerable developments have been made in recent years in our understanding of how cells orchestrate this complex interplay of processes, and have become the focus of research in osteogenesis. We will discuss current areas of preclinical and clinical research exploring the harnessing of mechanotransductive properties of cells and applying them therapeutically, both in the context of fracture healing and de novo bone formation in situations such as nonunion.

Cite this article: Bone Joint Res 2019;9(1):1–14.

Aims

The aim of this study was to systematically review the literature for evidence of the effect of a high-fat diet (HFD) on the onset or progression of osteoarthritis (OA) in mice.

Objectives

Experimental studies indicate that non-steroidal anti-inflammatory drugs (NSAIDs) may have negative effects on fracture healing. This study aimed to assess the effect of immediate and delayed short-term administration of clinically relevant parecoxib doses and timing on fracture healing using an established animal fracture model.

Objectives

The aim of this study was to analyze drain fluid, blood, and urine simultaneously to follow the long-term release of vancomycin from a biphasic ceramic carrier in major hip surgery. Our hypothesis was that there would be high local vancomycin concentrations during the first week with safe low systemic trough levels and a complete antibiotic release during the first month.