Refracture-related bone transport of tibia: technical notes and preliminary clinical results in nineteen cases

PURPOSE

Refracture is one of the main complications of bone transport, which brings additional physical and mental burden to surgeries and patients. We aimed to raise a new classification system of refracture-related bone transport based on the Simpson classification and to present our experience on treatment.

METHODS

This retrospective analysis included 19 patients with refracture-related bone transport (average age of 37.7 years; 18 men). We developed a modified Simpson classification system to assist decision-making (conservative versus surgical). The ASAMI criteria were used to assess the outcomes at last follow-up.

RESULTS

The mean follow-up was 12.3 ± 3.2 months. Complete union was achieved in all patients, with no reinfection. Based on the modified Simpson classification, refracture was Ia type (within regeneration area) in three cases, Ib (collapsed fracture at the regeneration area) in one case, Ic (stress fracture) in three cases, II (at the junction between the regenerate and original bone) in one case, III (at the docking site) in nine cases, and V (at distant site) in two cases. Refracture was managed conservatively in six cases and surgically in 13 cases. Average time to bone union was 2.8 ± 1.2 months in the conservative group versus 4.4 ± 1.4 months in the surgery group. Assessment at the final follow-up using the ASAMI criteria revealed excellent bone result in all patients, excellent functional results in six patients (31.6%), and good functional results in 13 patients.

CONCLUSIONS

The modified Simpson classification could include refracture at the docking site and stress fracture in the regeneration zone and provide some guidance in determining the appropriate treatment strategy.

Evaluation of stress-controlled high-cycle fatigue characteristics in PLA-wood fused deposition modeling 3D-printed parts under bending loads

PLA (Poly-lactic acid)-wood provides more biodegradability through natural fibers, a significant advantage of pure PLA. Nevertheless, these bio-composites may have inferior mechanical properties compared to non-degradable polymer composites, considering the lower strength of natural particles compared to synthetic fibers. This research examines the fatigue behavior of additive-manufactured biopolymer PLA-wood and assesses its comparability with pure PLA. Therefore, solid fatigue test samples were printed using the FDM (fused deposition modeling) method. Afterward, fully reversed rotary bending fatigue experiments were performed at 4 different stress levels (7.5 to 15 MPa) to extract the S-N curve of PLA-wood. Moreover, the fatigue fracture surfaces of the PLA-wood were investigated and compared at the highest and lowest stress levels using an FE-SEM (Field Emission Scanning Electron Microscopy), indicating more ductile fracture marks at higher stress levels. The fatigue lifetime of the PLA-wood decreased by 87.48% at the highest stress level (15 MPa), rather than the result at the lowest stress level (7.5 MPa). Additionally, the results demonstrated that the fatigue characteristics of the printed pure PLA and PLA-wood were comparable, suggesting that the 3D-printed PLA-wood with the used printing parameters can be an alternative choice.

HWJMSC-EVs promote cartilage regeneration and repair via the ITGB1/TGF-β/Smad2/3 axis mediated by microfractures

The current first-line treatment for repairing cartilage defects in clinical practice is the creation of microfractures (MF) to stimulate the release of mesenchymal stem cells (MSCs); however, this method has many limitations. Recent studies have found that MSC-derived extracellular vesicles (MSC-EVs) play an important role in tissue regeneration. This study aimed to verify whether MSC-EVs promote cartilage damage repair mediated by MFs and to explore the repair mechanisms. In vitro experiments showed that human umbilical cord Wharton's jelly MSC-EVs (hWJMSC-EVs) promoted the vitality of chondrocytes and the proliferation and differentiation ability of bone marrow-derived MSCs. This was mainly because hWJMSC-EVs carry integrin beta-1 (ITGB1), and cartilage and bone marrow-derived MSCs overexpress ITGB1 after absorbing EVs, thereby activating the transforming growth factor-β/Smad2/3 axis. In a rabbit knee joint model of osteochondral defect repair, the injection of different concentrations of hWJMSC-EVs into the joint cavity showed that a concentration of 50 µg/ml significantly improved the formation of transparent cartilage after MF surgery. Extraction of regenerated cartilage revealed that the changes in ITGB1, transforming growth factor-β, and Smad2/3 were directly proportional to the repair of regenerated cartilage. In summary, this study showed that hWJMSC-EVs promoted cartilage repair after MF surgery.

The Heel Complex: Anatomy, Imaging, Pathologic Conditions, and Treatment

The differential diagnosis for heel pain is broad but primarily involves abnormalities of the Achilles tendon, calcaneus, and plantar fascia. Achilles tendon disorders include tendinosis, tendinitis, and partial or complete tears. Tendinosis refers to tendon degeneration, while tendinitis is inflammation after acute overload. Untreated tendinosis can progress to partial or complete tears. Tendon disorders can be accompanied by paratenonitis or inflammation of the loose sheath enclosing the tendon. Initial management involves rehabilitation and image-guided procedures. Operative management is reserved for tendon tears and includes direct repair, tendon transfer, and graft reconstruction. The calcaneus is the most commonly fractured tarsal bone. The majority of fractures are intra-articular; extra-articular fractures, stress or insufficiency fractures, medial process avulsion, and neuropathic avulsion can also occur. Posterosuperior calcaneal exostosis or Haglund deformity, retrocalcaneal bursitis, and insertional Achilles tendinosis form the characteristic triad of Haglund syndrome. It is initially managed with orthotics and physiotherapy. Operative management aims to correct osseous or soft-tissue derangements. The plantar fascia is a strong fibrous tissue that invests the sole of the foot and contributes to midfoot stability. Inflammation or plantar fasciitis is the most common cause of heel pain and can be related to overuse or mechanical causes. Acute rupture is less common but can occur in preexisting plantar fasciitis. Conservative treatment includes footwear modification, calf stretches, and percutaneous procedures. The main operative treatment is plantar fasciotomy. Plantar fibromatosis is a benign fibroblastic proliferation within the fascia that can be locally aggressive and is prone to recurrence. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Arthroscopy and Microfracture for Osteochondritis Dissecans of the Capitellum in Adolescent Athletes Shows Favorable Return to Sport: A Systematic Review

PURPOSE

To assess return to sport (RTS) in the high-risk young athlete population with capitellar osteochondritis dissecans (OCD) undergoing arthroscopic microfracture (MFX) with or without debridement as well as associated indications, clinical outcomes, radiographic outcomes, and complications.

METHODS

A literature search of all published literature in the English language from PubMed, EMBASE, Scopus, and Cochrane from database inception to April 4, 2022, was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Included studies presented demographics and outcomes for adolescent (<21 years old) patients diagnosed with capitellar OCD who underwent arthroscopic MFX (or drilling/subchondral drilling) or MFX (or drilling/subchondral drilling) with debridement (or loose body removal/chondroplasty). Studies containing multiple surgical techniques that did not distinguish characteristics and outcomes of individual patients by surgical technique were excluded. Additionally, if there was overlap in patient populations between 2 studies, the study with less outcome data was excluded. Extracted data included study properties, patient demographics, lesion characteristics, surgery details, and patient outcomes, including range of motion, outcome scores, and RTS rates. Bias was assessed via the Methodological Index for Non-Randomized Studies (MINORS).

RESULTS

Nine studies of 136 patients and 138 elbows met criteria. Included articles were published between 2005 and 2020 with MINORS scores of 8 to 14 (50% to 88%). The age ranged from 12.7 to 15.7 years with most patients being involved in baseball or gymnastics and a rate of dominant elbow involvement of 55% to 100%. Patient follow-up ranged from 16 to 138 months. All 9 studies reported RTS, ranging from 65% to 100%. Six of these studies categorized the level to which the patient returned, with patients RTS at the same level of competition ranging from 60% to 100%. Six studies reported complications, with a range rate of 0% to 43%; there were a total of 10 complications, 7 of which required reoperations.

CONCLUSIONS

Arthroscopic MFX with or without arthroscopic debridement is a safe and effective treatment for OCD lesions of the capitellum in young, athletic patients. Included studies reported improved clinical, radiographic, and patient-reported outcomes. Aside from 1 study reporting an RTS of 65%, the rate of RTS ranged from 86% to 100%. The percentage of patients returning to sport at the same level of competition ranged from 60% to 100% with a time to RTS ranging from 4.1 to 5 months. A single study reported a complication rate of 43%, while remaining studies reported complication rates between 0% and 19%, with loose bodies being the most common complication requiring reoperation. Follow-up ranged from 16 to 138 months.

LEVEL OF EVIDENCE

Level IV, systematic review of Level IV studies.

Microfracture-coagulation for the real robotic liver parenchymal transection

The use of the robotic approach in liver surgery is exponentially increasing. Although technically the robot introduces several innovative features, the instruments linked with the traditional laparoscopic approach for the liver parenchymal transection are not available, which may result in multiple technical variants that may bias the comparative analysis between the different series worldwide. A real robotic approach, minimally efficient for the liver parenchymal transection, with no requirement of external tool, available for the already existing platforms, and applicable to any type of liver resection, counting on the selective use of the plugged bipolar forceps and the monopolar scissors, or "microfracture-coagulation" (MFC) transection method, is described in detail. The relevant aspects of the technique, its indications and methodological basis are discussed.

Failure in articular cartilage: Finite element predictions of stress, strain, and pressure under micro-indentation induced fracture

Articular cartilage is found at the distal end of long bones and is responsible for assisting in joint articulation. While articular cartilage has remarkable resistance to failure, once initially damaged, degeneration is nearly irreversible. Thus, understanding damage initiation is important. There are a few proposed mechanisms for articular cartilage failure initiation: (A) a single collagen fibril stress-based regime; (B) a rate-dependent regime captured by brittle failure at slow displacement rates (SDR) and ductile failure at fast displacement rates (FDR); and (C) a rate-dependent regime where failure is governed by pressurization fragmentation at SDR and governed by strain at FDR. The objective of this study was to use finite element (FE) models to provide evidence to support or refute these proposed failure mechanisms. Models were developed of microfracture experiments that investigated osmolarity (hypo-osmolar, normal osmolarity, and hyper-osmolar) and displacement rate (FDR and SDR) effects. Cartilage was modeled with a neo-Hookean ground matrix, strain-dependent permeability, nonlinear fibril reinforcement with viscoelastic fibril terms, and Donnan equilibrium swelling. Total stress, solid matrix stress, Lagrange strain, and fluid pressure were determined under the indenter tip at the moment of microfracture. Results indicated significant rate dependence across multiple outputs, which does not support (A) a single failure regime. Larger solid and fluid pressures at FDR than SDR did not support (C) a rate-dependent regime split by pressurization at SDR and strain at FDR. Consistent solid shear stresses at SDR and consistent third principal solid stresses at FDR support (B) the ductile-brittle failure regime. These findings help to shed light on the underlying mechanisms of articular cartilage failure, which have implications for the development of osteoarthritis.

Intravascular laser lithotripsy for calcium fracture in human coronary arteries

BACKGROUND

Electrical intravascular lithotripsy (E-IVL) uses shock waves to fracture calcified plaque.

AIMS

We aimed to demonstrate the ability of laser IVL (L-IVL) to fracture calcified plaques in ex vivo human coronary arteries and to identify and evaluate the mechanisms for increased vessel compliance.

METHODS

Shock waves were generated by a Ho:YAG (Holmium: yttrium-aluminium-garnet) laser (2 J, 5 Hz) and recorded by a high-speed camera and pressure sensor. Tests were conducted on phantoms and 19 fresh human coronary arteries. Before and after L-IVL, arterial compliance and optical coherence tomography (OCT) pullbacks were recorded, followed by histology. Additionally, microcomputed tomography (micro-CT) and scanning electron microscopy (SEM) were performed. Finite element models (FEM) were utilised to examine the mechanism of L-IVL.

RESULTS

Phantom cracks were obtained using 230 μm and 400 μm fibres with shock-wave pressures of 84±5.0 atm and 62±0.4 atm, respectively. Post-lithotripsy, calcium plaque modifications, including fractures and debonding, were identified by OCT in 78% of the ex vivo calcified arteries (n=19). Histological analysis revealed calcium microfractures (38.7±10.4 μm width) in 57% of the arteries which were not visible by OCT. Calcium microfractures were verified by micro-CT and SEM. The lumen area increased from 2.9±0.4 to 4.3±0.8 mm2 (p<0.01). Arterial compliance increased by 2.3±0.6 atm/ml (p<0.05). FEM simulations suggest that debonding and intimal tears are additional mechanisms for increased arterial compliance.

CONCLUSIONS

L-IVL has the capability to increase calcified coronary artery compliance by multiple mechanisms.

Applying additional autologous platelet-rich fibrin matrix or serial platelet-rich plasma to microfracture technique increases the quality of the repaired cartilage

PURPOSE

The aim of the present study is to investigate and compare the effects of biological adjuvants (platelet-rich plasma, platelet-rich fibrin matrix) and microfracture technique individually and in combination on full thickness chondral defects in a rabbit model.

METHODS

A total of 60 New Zealand White rabbits were randomly divided into six groups according to treatment modality as follows: control (C), microfracture (MF), platelet-rich plasma (PRP), platelet-rich fibrin matrix (PRFM), platelet-rich fibrin matrix after microfracture (MF + PRFM) and platelet-rich plasma after microfracture (MF + PRP) groups. The cartilage repair tissue was assessed histologically via International Cartilage Repair Score (ICRS) and macroscopically via ICRS macroscopic assessment scale.

RESULTS

It was shown that overall macroscopic scores of the groups with MF were higher than those of the groups without MF. The cell morphology observed in the defect areas was mostly characterized with non-chondrocyte cells in the groups without MF, whereas chondrocyte cells mostly prevailed in the groups with MF. There was a greater integration through the cartilage-like tissue in the MF + PRP and MF + PRFM groups. The control group showed either fissures or fissures partially filled with fibrous tissue. When the groups were individually examined, there were statistically significant differences between the control and MF groups (p = 0.002), between the control and MF + PRFM groups (p = 0.001), between the control and MF + PRP groups (p < 0.001), between the PRFM and MF + PRFM groups (p = 0.014) and between the PRFM and MF + PRP (p = 0.023) groups in terms of histological evaluation scores.

CONCLUSION

The application of PRP and PRFM in combination with MF treatment exhibited a positive impact on the repair and restoration of cartilage, and produced better outcomes than the individual use of PRP and PRFM. Nevertheless, in the treatment of full thickness chondral defects, the use of PRFM injection is recommended, which is performed intraoperatively at a single time and with no difficulty of repeating after surgery, instead of serial PRP injections based on the macroscopic and histological results obtained in the present study indicating that there was no significant difference between the use of these two adjuvants.

Repair of medial meniscus posterior root tear is effective for root healing and cartilage regeneration in opening wedge high tibial osteotomy

PURPOSE

This study aimed to determine whether the repair of a medial meniscus posterior root tear (MMPRT) is effective for MMPRT healing, cartilage regeneration, and clinical outcomes in opening wedge high tibial osteotomy (OWHTO).

METHODS

This retrospective study included 80 patients who underwent OWHTO and subsequent second-look arthroscopy. The patients were divided into OWHTO-with-MMPRT-repair (n = 40) and OWHTO alone (n = 40) groups, and the healing rates (complete/partial/failure) were compared. Each group was further divided into over- and under-corrected subgroups to compare healing rates. The International Cartilage Repair Society (ICRS) grade, cartilage defect size, Koshino stage, ICRS cartilage repair assessment score of the medial femoral condyle (MFC), and International Knee Documentation Committee (IKDC) scores between the OWHTO-with-MMPRT-repair and OWHTO alone groups were compared according to whether microfracture was performed on the MFC.

RESULTS

The overall healing rate of the MMPRT was higher in the OWHTO-with-MMPRT-repair group than that in the OWHTO alone group (P < 0.001). In addition, in the subgroup analysis, no difference in the MMPRT healing rate between the over-correction and under-correction groups when MMPRT repair was performed (n.s). In contrast, without MMPRT repair, the healing rate was lower in the under-correction group than that in the over-correction group (P = 0.03). Cartilage regeneration of the OWHTO-with-MMPRT-repair group was superior to that of the OWHTO alone group (P < 0.05). The IKDC subjective scores of the OWHTO-with-MMPRT-repair and OWHTO alone groups were 34.5 and 33.1 before surgery (n.s) and 50 and 47.2 at one year after surgery, respectively (n.s). These differences between the two groups for cartilage regeneration and IKDC subjective scores showed the same pattern regardless of microfractures.

CONCLUSIONS

MMPRT repair during OWHTO might improve MMPRT healing, even with under-correction, and cartilage regeneration of MFC, regardless of microfracture. However, OWHTO with MMPRT repair might not improve short-term clinical outcomes compared to OWHTO alone. Further randomized clinical trials are necessary.

LEVEL OF EVIDENCE

III, Retrospective cohort study.

Do we need to fix the anterior fracture component in insufficiency fractures of the pelvis? A biomechanical comparison on an FFP type IIIc fracture in an osteoporotic pelvic bone model

There is a growing understanding of the specific characteristics of insufficiency fractures of the pelvis and of general requirements for the treatment of affected patients with focus on early mobilization and effective pain reduction as the main goals of therapy. While there is consensus on the significance of achieving stability of the dorsal pelvic ring structures there is still an open discussion about the potential benefits of additional stabilization of an anterior fracture component. Within a biomechanical test setup, two established methods of dorsal fracture fixation were tested under axial loading (25-1200 N; 1000 test cycles) on an explicit osteoporotic bone model (n = 32) with a standardized FFP type IIIc fracture with and without additional fixation of the anterior fracture component. Dorsal fixation was performed with and long and a short 7.3 mm cannulated screw in S1 in one group (n = 16), and a trans sacral bar with an additional short 7.3 mm cannulated screw in S1 in the other group (n = 16). Half of the samples received a 7.3 mm cannulated retrograde transpubic screw for anterior fixation. The fixation with the trans sacral bar and the additional anterior screw fixation showed the highest rate of stability (p = 0.0014), followed by the double SI-screw fixation with stabilization of the anterior fracture (p = 0.0002). During testing, we observed the occurrence of new sacral fractures contralateral to the initial fracture in 22/32 samples. The results let us assume that stabilization of an additional anterior fracture component relevantly improves the stability of the entire ring construct and might prevent failure of the dorsal stabilization or further fracture progression.

Decellularized allogeneic cartilage paste with human costal cartilage and crosslinked hyaluronic acid-carboxymethyl cellulose carrier augments microfracture for improved articular cartilage repair

Articular cartilage lacks natural healing abilities and necessitates surgical treatments for injuries. While microfracture (MF) is a primary surgical approach, it often results in the formation of unstable fibrocartilage. Delivering hyaline cartilage directly to defects poses challenges due to the limited availability of autologous cartilage and difficulties associated with allogeneic cartilage delivery. We developed a decellularized allogeneic cartilage paste (DACP) using human costal cartilage mixed with a crosslinked hyaluronic acid (HA)-carboxymethyl cellulose (CMC) carrier. The decellularized allogeneic cartilage preserved the extracellular matrix and the nanostructure of native hyaline cartilage. The crosslinked HA-CMC carrier provided shape retention and moldability. In vitro studies confirmed that DACP did not cause cytotoxicity and promoted migration, proliferation, and chondrogenic differentiation of human bone marrow-derived mesenchymal stem cells. After 6 months of implantation in rabbit knee osteochondral defects, DACP combined with MF outperformed MF alone, demonstrating improved gait performance, defect filling, morphology, extracellular matrix deposition, and biomechanical properties similar to native cartilage. Thus, DACP offers a safe and effective method for articular cartilage repair, representing a promising augmentation to MF. STATEMENT OF SIGNIFICANCE: Directly delivering hyaline cartilage to repair articular cartilage defects is an ideal treatment. However, current allogeneic cartilage products face delivery challenges. In this study, we developed a decellularized allogeneic cartilage paste (DACP) by mixing human costal cartilage with crosslinked hyaluronic acid (HA)-carboxymethyl cellulose (CMC). DACP preserves extracellular matrix components and nanostructures similar to native cartilage, with HA-CMC ensuring shape retention and moldability. Our study demonstrates improved cartilage repair by combining DACP with microfracture, compared to microfracture alone, in rabbit knee defects over 6 months. This is the first report showing better articular cartilage repair using decellularized allogeneic cartilage with microfracture, without the need for exogenous cells or bioactive substances.

Macro/Microfracture evolution and instability behaviors of high-temperature granite under water-cooling subjected to Brazilian splitting test using the DIC technique

To investigate the evolution and stability characteristics of granite thermal damage, a series of Brazilian splitting tests is conducted on high-temperature granite samples using digital image correlation (DIC) technology. The results show that the Brazilian tensile strength and P-wave velocity exhibit a clear decline beyond a temperature threshold of 450~600°C, with a linear relationship between them. The presence of micro-cracks alters the stress transfer path, disrupting the stress balance on the Brazilian disc and leading to complex fracture patterns. At temperatures below 450°C, high strain areas and the development of micro-cracks occur at both the upper and lower loading ends of the granite Brazilian disc. However, these phenomena are only observed at the upper loading end when the temperature exceeds 450°C. Thermal cracks also cause changes in the internal structure of rock samples, and temperature variations can affect both the P-wave velocity and tensile strength. In terms of the relationship between P-wave velocity and Brazilian tensile strength (BTS) of high-temperature granite under water cooling, the negative exponential function model proposed in this study fits the experimental data very well.

Functional improvement of unicompartmental knee arthroplasty compared with total knee arthroplasty for subchondral insufficiency fracture of the knee

Subchondral insufficiency fracture of the knee (SIFK) causes acute knee pain in adults and often requires surgical management. Unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) are the two most common surgical treatments for SIFK. While both UKA and TKA have their advantages, there is no consensus for SIFK localized on the medial compartment. We hypothesized that patients with SIFK treated with UKA would show superior patient-reported outcomes compared to those who underwent TKA. A total of 90 patients with SIFK located medially were included in the TKA (n = 45) and UKA (n = 45) groups. Size of SIFK lesions were measured on MR images. Patient reported outcomes in the form of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Hospital Special Surgery (HSS) scores, and Knee Society Scores (KSS) were assessed preoperatively, postoperative 6, 12 months, and at the final follow-up. There were no differences in the size of the SIFK lesion between two groups. At 6 months, WOMAC score was better in the UKA group than the TKA group (p < .01). Both groups had a significant improvement in WOMAC, HSS, and KSS scores at the final follow-up compared to preoperative scores. The UKA group had better range of motion of the knee preoperatively and postoperatively than the TKA group (p < .01 and p < .01). UKA group showed a higher relative risk than the TKA group in terms of complications (RR = 3.0) but with no statistical significance (P = 0.31). Unicompartmental arthroplasty and total joint arthroplasty can produce successful outcomes in patients with SIFK with proper patient selection, regardless of the size of SIFK lesion.

Bisphosphonates and atypical femoral fractures: Is the location of the fracture associated with the time of consolidation?

INTRODUCTION

Bisphosphonates are commonly prescribed to mitigate the effects of osteoporosis, a condition associated with an increased risk of fracture. However, despite their success, there has been growing concern regarding the long-term use of bisphosphonates because of the increased risk of atypical subtrochanteric fractures of the femur (AFFs). The objective of this study was to describe a cohort of patients with AFFs and evaluate the risk of evolving to non-union, the time of consolidation associated with the location of the fracture, the time of use of the drug, and the implant involved in its treatment.

METHODS

This retrospective study recruited patients between June 2008 and May 2018. We identified patients with AFFs according to the task force criteria and a history of bisphosphonate use. We included all patients older than 65 years, with long-term use of bisphosphonates, AFF criteria according to the task force, and a follow-up of 12 months or longer. We studied the following variables: the time of use of bisphosphonates, localization of the fracture according to Hyodo et al., implant use, and fracture healing time, considering the presence of bone callus observed in two radiologic projections, which were measured in weeks.

RESULTS

Between June 2008 and May 2018, 72 patients met the task force criteria for AFFs. A total of 67 patients were included in this study. From this total, 37 were in the proximal region of the femur and 31 corresponded to the diaphyseal region. Univariate and multivariate analyses showed statistical significance in the time of bone healing compared with the different locations of the fracture along the femur.

CONCLUSION

According to our study, the localization of AFFs in patients with a history of bisphosphonate use influences the duration of bone healing.

Fibula flap in upper extremity segmental/critical size bone defects fixed with locking plates. Single-institution observational cohort

INTRODUCTION

Management of bone defects in the upper extremity can vary depending on the size and location of the defect. Large defects may require complex reconstruction techniques. Vascularized bone grafts, mainly free vascularized fibula flap (FVFF), have many advantages in the treatment of bone or osteocutaneous defects. However, complications such as graft fracture are the most common, with a free fibula flap for bone defects in the upper extremity. This study aimed to describe the results and complications associated with the treatment of posttraumatic bone defects in the upper extremity using FVFF. We hypothesized that performing osteosynthesis using locking plates would prevent or reduce the fracture of the fibula flap MATERIALS AND METHODS: This was a retrospective single-centre cohort study. Patients with segmental bone defects caused by trauma who underwent reconstructive surgery with FVFF fixed with locking compression plates (LCP) between January 2014 and 2022 were included. Demographic variables and preoperative data, such as bone defect, location, and time until reconstruction, were collected. Bone defects were classified according to the Testworth classification. Intraoperative variables included the length of the FVFF, type of graft (osteocutaneous or not), type and technique of arterial and venous sutures, number of veins used as output flow, and the osteosynthesis technique used.

RESULTS

Ten patients were included (six humerus, three ulna, and one radius). All patients had critical-size bone defects, and nine patients had a history of infection. In 9 of 10 patients, bone fixation was performed with a bridge LCP and in one patient with two LCP plates. In eight cases, the FVFF was osteocutaneous. All the patients showed bone healing at the end of the follow-up period. There was one early complication, donor site wound dehiscence, and two long-term complications (proximal radioulnar synostosis and soft-tissue defect).

CONCLUSION

A high rate of bone union with a low rate of complications can be obtained with an FVFF in upper extremity segmental/critical-size bone defects. Rigid fixation with locking plates avoids stress fractures of the grafts, mainly in humeral reconstruction. However, in these cases, a bridge plate should be used.

Microstructural fatigue fracture behavior of glycated cortical bone

The current study aims to simulate fatigue microdamage accumulation in glycated cortical bone with increased advanced glycation end-products (AGEs) using a phase field fatigue framework. We link the material degradation in the fracture toughness of cortical bone to the high levels of AGEs in this tissue. We simulate fatigue fracture in 2D models of cortical bone microstructure extracted from human tibias. The results present that the mismatch between the critical energy release rate of microstructural features (e.g., osteons and interstitial tissue) can alter crack initiation and propagation patterns. Moreover, the high AGEs content through the increased mismatch ratio can cause the activation or deactivation of bone toughening mechanisms under cyclic loading. The fatigue fracture simulations also show that the lifetime of diabetic cortical bone samples can be dependent on the geometry of microstructural features and the mismatch ratio between the features. Additionally, the results indicate that the trapped cracks in cement lines in the diabetic cortical microstructure can prevent further crack growth under cyclic loading. The present findings show that alterations in the materials heterogeneity of microstructural features can change the fatigue fracture response, lifetime, and fragility of cortical bone with high AGEs contents. Cortical bone models are created from microscopy images taken from the cortical cross-section of human tibias. Increased glycation contents in the cortical bone sample can change the crack growth trajectories.

Investigation of the effects of subacromial bursal tissue preservation and microfracture procedure on healing after rotator cuff repair in a rat model

INTRODUCTION

The aim of this study is to compare the preservation of bursal tissue and microfracture techniques and to examine the effectiveness of the combination of the two methods in rotator cuff tear healing in the rat shoulder.

HYPOTHESIS

Bursal tissue preservation combined with microfracture is more effective in the rotator cuff repair.

MATERIALS AND METHODS

Twenty-three male Sprague-Dawley rats were randomly divided into two groups. The bursal tissue was preserved in group 1 (n=11) and excised in group 2 (n=12). Groups were categorized into subgroups as L (left) and R (right) based on the shoulder side receiving microfracture (L received microfracture, R did not). Histopathological examination was performed using modified Bonar Score System.

RESULTS

Cell morphology grades of group 1 were lower than group 2 (p<0.05). In terms of collagen measurements, the grade of group 1L (bursa preservation+microfracture) was lower than groups 1R, 2L, and 2R, and the grade of group 1R was lower than groups 2L and 2R. Cellularity grades of group 2 were higher than group 1 (p<0.05). Extracellular matrix grades of group 1 were lower than group 2 (p<0.05). The overall grades were lower in group 1 than in group 2 (p<0.05).

DISCUSSION

Combined treatment of bursal tissue preservation and microfracture was the most efficient method as determined by healing findings in histopathological specimens. Preservation of bursal tissue was a more effective option in tendon healing than performing only microfracture.

LEVEL OF PROOF

II, animal research.

Advanced glycation and glycoxidation end products in bone

Hyperglycemia and oxidative stress, enhanced in diabetes and aging, result in excessive accumulation of advanced glycation and glycoxidation end products (AGEs/AGOEs) in bone. AGEs/AGOES are considered to be "the missing link" in explaining increased skeletal fragility with diabetes, aging, and osteoporosis where increased fracture risk cannot be solely explained by bone mass and/or fall incidences. AGEs/AGOEs disrupt bone turnover and deteriorate bone quality through alterations of organic matrix (collagen and non-collagenous proteins), mineral, and water content. AGEs and AGOEs are also associated with bone fragility in other conditions such as Alzheimer's disease, circadian rhythm disruption, and cancer. This review explains how AGEs and AGOEs accumulate in bone and impact bone quality and bone fracture, and how AGES/AGOEs are being targeted in preclinical and clinical investigations for inhibition or removal, and for prediction and management of diabetic, osteoporotic and insufficiency fractures.

Osteoid osteomas of the hip: a well-recognized entity with a proclivity for misdiagnosis

OBJECTIVES

The diagnosis of osteoid osteomas (OO) about the hip can be challenging as presenting symptoms can mimic other, more common, periarticular pathologies. Our aims were to identify the most common misdiagnoses and treatments, mean delay in diagnosis, characteristic imaging features and provide tips for avoiding diagnostic imaging pitfalls for patients with OO of the hip.

METHODS

We identified 33 patients (34 tumors) with OO about the hip who were referred for radiofrequency ablation between 1998 and 2020. Imaging studies reviewed included radiographs (n = 29), CT (n = 34), and MRI (n = 26).

RESULTS

The most common initial diagnoses were femoral neck stress fracture (n = 8), femoroacetabular impingement (FAI) (n = 7), and malignant tumor or infection (n = 4). The mean time from symptom onset to diagnosis of OO was 15 months (range, 0.4-84). The mean time from initial incorrect diagnosis to OO diagnosis was 9 months (range, 0-46).

CONCLUSIONS

The diagnosis of OO of the hip is challenging, with up to 70% of cases initially misdiagnosed as a femoral neck stress fracture, FAI, bone tumor, or other joint pathology in our series. Consideration of OO in the differential diagnosis of hip pain in adolescent patients and awareness of the characteristic imaging findings are critical for making an accurate diagnosis.

KEY POINTS

• The diagnosis of osteoid osteoma of the hip can be challenging, as demonstrated by long delays in time to initial diagnosis and high rates of misdiagnoses which can lead to inappropriate interventions. • Familiarity with the spectrum of imaging features of OO, especially on MRI, is imperative given the increase in the utilization of this modality for the evaluation of young patients with hip pain and FAI. • Consideration of OO in the differential diagnosis of hip pain in adolescent patients and awareness of the characteristic imaging findings, including bone marrow edema and the utility of CT, are critical for making a timely and accurate diagnosis.

A modified induced membrane 2-stage technique using a thoracodorsal artery perforator free flap followed by vascularized or non-vascularized free fibular transfer for the treatment of complex bone infection with concomitant severe soft tissue lesion-A case series of 9 cases

Treatment of post-traumatic complex bone infection is very challenging. The two principal bone reconstruction approaches are the single-stage vascularized bone graft technique and the two-stage induced membrane technique (IMT). Here we introduce a modified 2-stage induced membrane technique (MIMT) for complex long bone infection with a major bone defect and a concomitant severe soft tissue lesion. The 2-stage procedure consists of bone debridement, placement of a PMMA spacer and soft tissue reconstruction with a thoracodorsal artery perforator free flap ("Tdap") at stage 1. At stage 2, the thoracodorsal artery perforator flap is elevated and a fibular strut graft (either vascularized of non-vascularized) is placed for bone reconstruction. We retrospectively analyzed the extents of lower extremity, long bone, post-traumatic bone infection treated via MIMT from 2008 to 2020. There were nine such cases (eight males) of mean age 59.8 (range 31 to 79) years. The osteomyelitis durations ranged from 3 to 360 months (mean 53 months). The cortical bone defect sizes was ranged from 9 to 14 cm (mean10.7 cm). All skin resurfacing employed Tdap. Vascularized fibular grafts were placed in six patients and non-vascularized grafts were placed in three. The fibular graft size ranged from 12.5 to 19 cm (mean 16.2 cm). Non-vascularized iliac bone grafts served as the fibula docking sites. Unfortunately, all patients suffered complications before bone union was achieved. One case of plate stress fracture and one case of screw fracture required plate and screw change. In three cases of cellulitis, one resolved by use of intravenous antibiotics, others required plate and screw removal. Wound disruption required re-suture and distal skin flap partial necrosis was covered by perforator-based island flap. One case of fibular stress fracture needed cast for 4 weeks. A peroneal nerve palsy patient recovered spontaneously. Bone union was achieved after 6 months in five patients and after 8 months in three (mean 6.9 months). All patients were able to walk unaided. The follow-up period ranged from 2 to 14 years (mean 6.2 years). MIMT saves the limbs in cases with difficult post-traumatic bone infection. It is valid treatment option for complex bone infections with severe soft tissue lesions. However, even with this technique potential complication must be considered.

Transplantable stem cell nanobridge scaffolds for accelerating articular cartilage regeneration

Microfracture technique for treating articular cartilage defects usually has poor clinical outcomes due to critical heterogeneity and extremely limited in quality. To improve the effects of current surgical technique (i.e., microfracture technique), we propose the transplantable stem cell nanobridge scaffold, acting as a protective bridge between host tissue and defected cartilage as well as microfracture-derived cells. Nanobridge scaffolds have a sophisticated nanoaligned structure with freestanding and flexible shapes for imposing direct structural guidance to cells including transplanted stem cells and host cells, and it can induce not only chondrocyte migration but also stem cell differentiation, maturation, and growth factor secretion. The transplantable stem cell nanobridge scaffold is capable of reconstructing the defected cartilage with homogeneous architecture and highly enhanced adhesive stress similar with native cartilage tissue by the synergistic effects of stem cells-based chondro-induction and nanotopography-based chondro-conduction. Our findings demonstrate a significant advancement in the traditional treatment technique by using a nanoengineered tool for achieving successful cartilage regeneration.

Association of Phantomless Dual-Energy CT-based Volumetric Bone Mineral Density with the Prevalence of Acute Insufficiency Fractures of the Spine

RATIONALE AND OBJECTIVES

To evaluate the bone mineral density (BMD) of the lumbar spine derived from dual-energy CT (DECT)-based volumetric material decomposition and its association with acute insufficiency fractures of the thoracolumbar spine.

MATERIALS AND METHODS

L1 of 160 patients (77 men, 83 women; mean age 64.3 years, range, 22-94 years) who underwent third-generation dual-source DECT between January 2016 and December 2021 due to suspected insufficiency fractures was retrospectively analyzed. All depicted vertebrae were examined for signs of recent fractures. A dedicated DECT postprocessing software using material decomposition was applied for phantomless BMD assessment. Receiver-operating characteristic (ROC) analysis identified optimal BMD thresholds. Associations of BMD, sex, and age with the occurrence of insufficiency fractures were examined with logistic regression models.

RESULTS

A DECT-derived BMD threshold of 120.40 mg/cm³ yielded 90.1% specificity and 59.32% sensitivity to differentiate patients with at least one insufficiency fracture from patients without fracture. No patient without fracture had a DECT-derived BMD below 85 mg/cm3. Lower DECT-derived bone mineral density was associated with an increased risk of insufficiency fractures (Odds ratio of 0.93, 95% CI, 0.91-0.96, p < 0.001). Overall ROC-derived AUC was 0.82 (p < 0.0001) for the differentiation of patients that sustained an insufficiency fracture from the control group.

CONCLUSION

Dual-Energy CT-based BMD assessment can accurately differentiate patients with acute insufficiency fractures of the thoracolumbar spine from patients without fracture. This algorithm can be used for phantomless risk stratification of patients undergoing routine CT to sustain insufficiency fractures of the thoracolumbar spine The identified cut-off value of 120.4 mg/cm³ is in line with current American College of Radiology (ACR) recommendations to differentiate healthy individuals from those with reduced bone mineral density.

Sacral stress fracture in a young-adult, long-distance runner: an underestimated cause of low back pain

Sacral stress fractures (SSFs) in physically active young patients are frequently misdiagnosed due to the lack of specificity of signs and symptoms. Over the last years, these injuries have been described as rare, although some studies report that the incidence of an SSF in athletes may be as high as 20%.We describe a case of a male long-distance runner in his late 20s with a 1-month undiagnosed SSF. The patient complaints included insidious right low back and buttock pain without trauma that started after running a marathon. MRI revealed an extensive area of bone marrow oedema in the right sacral ala consistent with an SSF.This case highlights the importance of investigating SSF in young-athlete patients who were otherwise healthy, using appropriate imaging modalities to assess the presence and morphology of a fracture.

Histomorphological Investigation of Microfracture Location in a Rabbit Osteochondral Defect Model

BACKGROUND

Microfracture is the most common treatment for cartilage defects of the knee. In microfracture surgery, holes are randomly drilled into the subchondral bone. The effect of the hole's location on its interaction with the cartilage defect site and its influence on the healing process is currently uncertain.

PURPOSE

To investigate the effects of different microfracture locations on healing in a rabbit knee osteochondral defect model.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 29 adult New Zealand White rabbits were divided into 5 groups. In the healthy cartilage control group (n = 5), no surgical procedure was performed. Cylindrical full-thickness cartilage defects (5 × 3 mm) were created in the patellar groove of the remaining 24 rabbits. In the defect control group (n = 6), only the defect was created. A microfracture was performed at the 12-o'clock position (group peripheral single; n = 6), centrally (group central; n = 6), and at the 12- and 6-o'clock positions (group peripheral double; n = 6) of the defect. The animals were sacrificed after 8 weeks. Cartilage healing was evaluated by International Cartilage Regeneration & Joint Preservation Society (ICRS) score, modified O'Driscoll score, immunohistochemical analysis (type 1 collagen, type 2 collagen, and aggrecan), and scanning electron microscopy analysis.

RESULTS

In group peripheral double, better cartilage healing was observed in all parameters compared with the other groups (P < .05). Group peripheral double had the greatest amount of filling, with 79% of the defect area filled with fibrocartilage repair tissue. Group peripheral single demonstrated filling of 73% of the defect area, group central 56%, and the defect control group 45%. The ICRS score was significantly higher in group peripheral single compared with group central and the defect control group. Type 2 collagen and aggrecan immunoreactivity were significantly stronger in group central than group peripheral single and the defect control group (P < .05).

CONCLUSION

Microfracture performed at the peripheral margin of the defect had better filling characteristics in a rabbit model. This study suggests that interaction of pluripotent cells released from the microfracture site with the intact cartilage may enhance the quality of the repair tissue.

CLINICAL RELEVANCE

The location of microfracture holes in relation to the peripheral border of the osteochondral defect (to the intact cartilage) is important in both the quality and the quantity of the newly formed repair tissue.

Novel Standalone Motion-Sparing Pelvic Fixation Prevents Short-Term Insufficiency Fractures After Midsacrectomies Without Sacrificing Normal, Mobile Lumbar Segments Traditionally Used for Stabilization

BACKGROUND AND OBJECTIVES

Sacrectomy is often the treatment of choice to provide the greatest chance of progression-free and overall survival for patients with primary malignant bone tumors of the sacrum. After midsacrectomy, the stability of the sacropelvic interface is diminished, resulting in insufficiency fractures. Traditional stabilization involves lumbopelvic fixation but subjects normal mobile segments to fusion. The purpose of this study was to determine whether standalone intrapelvic fixation is a safe adjunct to midsacrectomy, avoiding both sacral insufficiency fractures and the morbidity of instrumenting into the mobile spine.

METHODS

A retrospective study identified all patients who underwent resection of sacral tumors at 2 comprehensive cancer centers between June 2020 and July 2022. Demographic, tumor-specific, operative characteristics and outcome data were collected. The primary outcome was presence of sacral insufficiency fractures. A retrospective data set of patients undergoing midsacrectomy without hardware placement was collected as a control.

RESULTS

Nine patients (5 male, 4 female), median age 59 years, underwent midsacrectomy with concomitant placement of standalone pelvic fixation. No patients developed insufficiency fractures during the 216 days of clinical and 207 days of radiographic follow-up. There were no adverse events attributable to the addition of standalone pelvic fixation. In our historical cohort of partial sacrectomies without stabilization, there were 4/25 patients (16%) with sacral insufficiency fractures. These fractures appeared between 0 and 5 months postoperatively.

CONCLUSION

A novel standalone intrapelvic fixation after partial sacrectomy is a safe adjunct to prevent postoperative sacral insufficiency fractures in patients undergoing midsacrectomy for tumor. Such a technique may allow for long-term sacropelvic stability without sacrificing mobile lumbar segments.

Evaluation of cyclic fatigue and bending test for different Nickle-Titanium files

AIM

To compare cyclic fatigue resistance and bending for three different nickel-titanium (NiTi) rotary files.

MATERIALS AND METHODS

A sample of 90 NiTi instruments size (25.06) was divided into three groups with 30 files in each: Race Evo files (FKG Dentaire, Switzerland); Tia Tornado Blue files (TiaDent Inc., Texas- USA); One Curve files (Micro-Mega, France). Then each group was subdivided into two groups with 15 files in each; a bending test was performed for one group, and a dynamic cyclic fatigue test at body temperature was performed for the other group. Files fractured by cyclic fatigue were randomly picked from all tested groups for Scanning Electron Microscopy (SEM) (Jeol, Tokyo, Japan). In addition, the test included measuring the broken part of the files tested using (Electronic Micrometre Calliper with LCD Screen, Inch and Millimetre Conversion, Adoric- Taiwan). Data were statistically analyzed using a one-way ANOVA with Tukey-HSD post hoc test.

RESULTS

It was found that maximum load [gf] was less (meaning more flexible) in the group of Tia Tornado Blue with a statistically significant difference in comparison with Race Evo and One Curve. The number of cycles to fracture (NCF) in the Race Evo group was significantly higher than the groups of One Curve and Tia Tornado Blue.

CONCLUSIONS

Within the limitation of the study, it could be concluded that Race Evo files were more resistant to cyclic fatigue fracture and Tia Tornado Blue files were more flexible compared to the other tested files.

Red flags to screen for vertebral fracture in people presenting with low back pain

BACKGROUND

Low back pain is a common presentation across different healthcare settings. Clinicians need to confidently be able to screen and identify people presenting with low back pain with a high suspicion of serious or specific pathology (e.g. vertebral fracture). Patients identified with an increased likelihood of having a serious pathology will likely require additional investigations and specific treatment. Guidelines recommend a thorough history and clinical assessment to screen for serious pathology as a cause of low back pain. However, the diagnostic accuracy of recommended red flags (e.g. older age, trauma, corticosteroid use) remains unclear, particularly those used to screen for vertebral fracture.

OBJECTIVES

To assess the diagnostic accuracy of red flags used to screen for vertebral fracture in people presenting with low back pain. Where possible, we reported results of red flags separately for different types of vertebral fracture (i.e. acute osteoporotic vertebral compression fracture, vertebral traumatic fracture, vertebral stress fracture, unspecified vertebral fracture).

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 26 July 2022.

SELECTION CRITERIA

We considered primary diagnostic studies if they compared results of history taking or physical examination (or both) findings (index test) with a reference standard test (e.g. X-ray, magnetic resonance imaging (MRI), computed tomography (CT), single-photon emission computerised tomography (SPECT)) for the identification of vertebral fracture in people presenting with low back pain. We included index tests that were presented individually or as part of a combination of tests.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data for diagnostic two-by-two tables from the publications or reconstructed them using information from relevant parameters to calculate sensitivity, specificity, and positive (+LR) and negative (-LR) likelihood ratios with 95% confidence intervals (CIs). We extracted aspects of study design, characteristics of the population, index test, reference standard, and type of vertebral fracture. Meta-analysis was not possible due to heterogeneity of studies and index tests, therefore the analysis was descriptive. We calculated sensitivity, specificity, and LRs for each test and used these as an indication of clinical usefulness. Two review authors independently conducted risk of bias and applicability assessment using the QUADAS-2 tool.

MAIN RESULTS

This review is an update of a previous Cochrane Review of red flags to screen for vertebral fracture in people with low back pain. We included 14 studies in this review, six based in primary care, five in secondary care, and three in tertiary care. Four studies reported on 'osteoporotic vertebral fractures', two studies reported on 'vertebral compression fracture', one study reported on 'osteoporotic and traumatic vertebral fracture', two studies reported on 'vertebral stress fracture', and five studies reported on 'unspecified vertebral fracture'. Risk of bias was only rated as low in one study for the domains reference standard and flow and timing. The domain patient selection had three studies and the domain index test had six studies rated at low risk of bias. Meta-analysis was not possible due to heterogeneity of the data. Results from single studies suggest only a small number of the red flags investigated may be informative. In the primary healthcare setting, results from single studies suggest 'trauma' demonstrated informative +LRs (range: 1.93 to 12.85) for 'unspecified vertebral fracture' and 'osteoporotic vertebral fracture' (+LR: 6.42, 95% CI 2.94 to 14.02). Results from single studies suggest 'older age' demonstrated informative +LRs for studies in primary care for 'unspecified vertebral fracture' (older age greater than 70 years: 11.19, 95% CI 5.33 to 23.51). Results from single studies suggest 'corticosteroid use' may be an informative red flag in primary care for 'unspecified vertebral fracture' (+LR range: 3.97, 95% CI 0.20 to 79.15 to 48.50, 95% CI 11.48 to 204.98) and 'osteoporotic vertebral fracture' (+LR: 2.46, 95% CI 1.13 to 5.34); however, diagnostic values varied and CIs were imprecise. Results from a single study suggest red flags as part of a combination of index tests such as 'older age and female gender' in primary care demonstrated informative +LRs for 'unspecified vertebral fracture' (16.17, 95% CI 4.47 to 58.43). In the secondary healthcare setting, results from a single study suggest 'trauma' demonstrated informative +LRs for 'unspecified vertebral fracture' (+LR: 2.18, 95% CI 1.86 to 2.54) and 'older age' demonstrated informative +LRs for 'osteoporotic vertebral fracture' (older age greater than 75 years: 2.51, 95% CI 1.48 to 4.27). Results from a single study suggest red flags as part of a combination of index tests such as 'older age and trauma' in secondary care demonstrated informative +LRs for 'unspecified vertebral fracture' (+LR: 4.35, 95% CI 2.92 to 6.48). Results from a single study suggest when '4 of 5 tests' were positive in secondary care, they demonstrated informative +LRs for 'osteoporotic vertebral fracture' (+LR: 9.62, 95% CI 5.88 to 15.73). In the tertiary care setting, results from a single study suggest 'presence of contusion/abrasion' was informative for 'vertebral compression fracture' (+LR: 31.09, 95% CI 18.25 to 52.96).

AUTHORS' CONCLUSIONS

The available evidence suggests that only a few red flags are potentially useful in guiding clinical decisions to further investigate people suspected to have a vertebral fracture. Most red flags were not useful as screening tools to identify vertebral fracture in people with low back pain. In primary care, 'older age' was informative for 'unspecified vertebral fracture', and 'trauma' and 'corticosteroid use' were both informative for 'unspecified vertebral fracture' and 'osteoporotic vertebral fracture'. In secondary care, 'older age' was informative for 'osteoporotic vertebral fracture' and 'trauma' was informative for 'unspecified vertebral fracture'. In tertiary care, 'presence of contusion/abrasion' was informative for 'vertebral compression fracture'. Combinations of red flags were also informative and may be more useful than individual tests alone. Unfortunately, the challenge to provide clear guidance on which red flags should be used routinely in clinical practice remains. Further research with primary studies is needed to improve and consolidate our current recommendations for screening for vertebral fractures to guide clinical care.

Rod Attachment Induces Significant Strain in Lumbosacral Fixation

STUDY DESIGN

This was a laboratory investigation.

OBJECTIVE

Rod attachment can induce significant pedicle screw-and-rod pre- strain that may predispose the instrumentation to failure. This study investigated how in vitro L5-S1 rod strain and S1 screw strain during rod-screw attachment (pre-strain) compared with strains recorded during pure-moment bending ( test- strain).

SUMMARY OF BACKGROUND DATA

The lumbosacral junction is highly vulnerable to construct failure due to rod fatigue fracture, sacral screw pull-out, and screw fatigue fracture.

MATERIALS AND METHODS

Twelve cadaveric specimens were instrumented with L2-ilium pedicle screws and rod. Strain gauges on contoured rods and sacral screws recorded strains during sequential rod-to-screw tightening (pre-strains). The same instrumented constructs were immediately tested in a 6-degree-of-freedom apparatus under continuous loading to 7.5 Nm in multidirectional bending while recording instrumentation test-strains. Rod and screw pre-strains and test-strains were compared using 1-way repeated-measures analysis of variance followed by Holm-Šidák paired analysis (significant at P <0.05).

RESULTS

The mean first (171±192 µE) and second (322±269 µE) rod attachment pre-strains were comparable to mean test-strains during flexion (265±109 µE) and extension (315±125 µE, P ≥0.13). The mean rod attachment pre-strain was significantly greater than mean test-strains during bidirectional lateral bending (40±32 µE ipsilateral and 39±32 µE contralateral, P <0.001) and axial rotation (72±60 µE ipsilateral and 60±57 µE contralateral, P <0.001). The mean first and second sacral screw pre-strains during rod attachment (1.03±0.66 and 1.39±1.00 Nm, respectively) did not differ significantly ( P =0.41); however, the mean sacral screw pre-strain during final (second) rod attachment was significantly greater than screw test-strains during all directions of movement (≤0.81 Nm, P ≤0.03).

CONCLUSIONS

Instrumentation pre-strains imposed during in vitro rod-screw attachment of seemingly well-contoured rods in L2-ilium fixation are comparable to, and at times greater than, strains experienced during in vitro bending. Spine surgeons should be aware of the biomechanical consequences of rod contouring and attachment on construct vulnerability.

Tumour induced osteopenia due to phosphaturic mesenchymal sinonasal tumour presenting with delayed onset insufficiency fractures

We present a case of a 48-year-old female who presented with epistaxis. Magnetic resonance imaging (MRI) revealed a mass within the left nasal cavity which was revealed to be a phosphaturic mesenchymal sinonasal tumour. The patient defaulted treatment at this stage and later re-presented with pelvic and groin pain for which plain radiographs and computed tomography (CT) scan demonstrated diffuse osteopenia and multiple pelvic fractures of varying ages. MRI of the pelvis and both thighs revealed abnormal marrow signal of the bones and confirmed the presence of pelvic fractures. Multiple pseudo-fractures were seen at both femurs and scapula. The radiological findings along with abnormal biochemical markers were attributed to the paraneoplastic entity of tumour induced osteomalacia, in the context of unresected phosphaturic mesenchymal tumour. The tumour was resected, and patient showed complete reversal of the associated biochemical abnormalities. This case exemplifies that with early identification and complete resection of the causative tumour, the prognosis is excellent.

Chronic Nerve Root Injury in Pediatric Patients With Chronic Lumbar Stress Fractures: A Retrospective Review

INTRODUCTION

Many orthopedic providers currently treat chronic spondylolysis as self-limited fractures. While the condition has previously been associated with back pain in pediatrics, there has been little attention on the risk of neurologic harm. Electromyography (EMG) is a common study used to evaluate nerve injury, but it has not been previously reported for testing pediatric patients with stress fractures. In this study, pediatric patients with chronic pars fractures and muscle extremity weakness who underwent EMG testing were reviewed to analyze their risk of chronic nerve injury.

METHODS

120 pediatric patients who underwent EMG testing between 2015 and 2021 were analyzed, and 41(21F,20M) patients with a mean age of 16(13-20) met criteria of chronic lumbar pediatric spondylolysis with weakness on ankle dorsiflexion or plantarflexion. No exclusions were made. Initial EMG testing was indicated for the extremity weakness; pain was not the major concern. All exams were completed by JWM. Thin-cut lumbar CT studies were done at the same institution, and EMGs were completed by one of three physiatrists. EMGs were determined as normal, abnormal but not meeting chronic nerve injury threshold, or abnormal and meeting threshold for chronic nerve injury.

RESULTS

Of the 41 patients, 33 had bilateral and 8 had unilateral fractures with 95% (39/41) of them located at L4 or L5. 55% (18/33) of the bilateral fractures had abnormal EMGs and demonstrated chronic nerve injury; 1 had an abnormal EMG but did meet chronic injury threshold. 75% (6/8) of the unilateral fractures had abnormal EMGs and demonstrated chronic nerve injury; 1 had an abnormal EMG but did meet chronic injury threshold. Overall, 36% (15/41) had normal EMGs, 5% (2/41) had abnormal results but did not reach chronic injury threshold, and 59% (24/41) met threshold for chronic nerve injury.

CONCLUSION

Chronic pars fractures have historically been treated as a benign and self-limited sports injury. However, our analysis showed that 59% of adolescent patients presenting with chronic pars fractures and dorsiflexion or plantarflexion weakness have developed a chronic nerve injury. This study is the first to demonstrate the risk of neurologic harm in unhealed pediatric lumbar stress fractures, and it indicates the importance of EMG testing in young patients presenting with chronic spondylolysis and extremity weakness.

Fatigue crack propagation and fracture toughness of cortical bone are radiation dose-dependent

Cortical bone allograft sterilized with a standard γ-radiation dose of 25-35kGy has demonstrated reduced static and cyclic fracture resistance compared with unirradiated bone. To mitigate radiation damage, we recently observed a dose-dependent response of high-cycle fatigue behavior of human cortical bone from 0 to 25 kGy, with lower doses exhibiting logarithmically longer fatigue lives. The objectives of this study were as follows: (1) to determine whether fracture toughness, work-to-fracture, and fatigue crack propagation resistance of human cortical bone are also radiation dose-dependent, and (2) to determine the associations of radiation dose and a Raman biomarker for collagen disorder with fracture properties. Compact tension specimens were machined from two donor femoral pairs and allocated to four treatment groups: 0 (unirradiated control), 10, 17.5, and 25 kGy. Fracture toughness specimens were monotonically loaded to failure and the critical stress intensity factor (KC ) was determined. Work-to-fracture was calculated from the load versus displacement integral up to fracture. Fatigue crack propagation specimens were cyclically loaded under constant room-temperature irrigation and fatigue crack growth rate (da/dN) and cyclic stress intensity (∆K) were calculated. Fracture toughness, work-to-fracture, and fatigue crack propagation resistance decreased 18%, 33%, and 15-fold from 0 to 25 kGy, respectively (p < 0.05). Radiation dose was more predictive of fracture properties than collagen disorder. These findings support that quasi-static and fatigue fracture properties of cortical bone are radiation dose-dependent within this dose range. The structural alterations arising from irradiation that cause these losses in fracture resistance remain to be elucidated.

Ultrasound and shockwave therapy for acute fractures in adults

BACKGROUND

The morbidity and socioeconomic costs of fractures are considerable. The length of time to healing is an important factor in determining a person's recovery after a fracture. Ultrasound may have a therapeutic role in reducing the time to union after fracture by stimulating osteoblasts and other bone-forming proteins. This is an update of a review previously published in February 2014.   OBJECTIVES: To assess the effects of low-intensity ultrasound (LIPUS), high-intensity focused ultrasound (HIFUS) and extracorporeal shockwave therapies (ECSW) as part of the treatment of acute fractures in adults.  SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase (1980 to March 2022), Orthopaedic Proceedings, trial registers and reference lists of articles.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs including participants over 18 years of age with acute fractures (complete or stress fractures) treated with either LIPUS, HIFUS or ECSW versus a control or placebo-control.

DATA COLLECTION AND ANALYSIS

We used standard methodology expected by Cochrane. We collected data for the following critical outcomes: participant-reported quality of life, quantitative functional improvement, time to return to normal activities, time to fracture union, pain, delayed or non-union of fracture. We also collected data for treatment-related adverse events. We collected data in the short term (up to three months after surgery) and in the medium term (later than three months after surgery).   MAIN RESULTS: We included 21 studies, involving 1543 fractures in 1517 participants; two studies were quasi-RCTs. Twenty studies tested LIPUS and one trial tested ECSW; no studies tested HIFUS. Four studies did not report any of the critical outcomes. All studies had unclear or high risk of bias in at least one domain. The certainty of the evidence was downgraded for imprecision, risk of bias and inconsistency. LIPUS versus control (20 studies, 1459 participants) We found very low-certainty evidence for the effect of LIPUS on Health-related quality of life (HRQoL) measured by SF-36 at up to one year after surgery for lower limb fractures (mean difference (MD) 0.06, 95% confidence interval (CI) -3.85 to 3.97, favours LIPUS; 3 studies, 393 participants). This result was compatible with a clinically important difference of 3 units with both LIPUS or control. There may be little to no difference in time to return to work after people had complete fractures of the upper or lower limbs (MD 1.96 days, 95% CI -2.13 to 6.04, favours control; 2 studies, 370 participants; low-certainty evidence).  There is probably little or no difference in delayed union or non-union up to 12 months after surgery (RR 1.25, 95% CI 0.50 to 3.09, favours control; 7 studies, 746 participants; moderate-certainty evidence). Although data for delayed and non-union included both upper and lower limbs, we noted that there were no incidences of delayed or non-union in upper limb fractures. We did not pool data for time to fracture union (11 studies, 887 participants; very low-certainty evidence) because of substantial statistical heterogeneity which we could not explain. In upper limb fractures, MDs ranged from 0.32 to 40 fewer days to fracture union with LIPUS. In lower limb fractures, MDs ranged from 88 fewer days to 30 more days to fracture union. We also did not pool data for pain experienced at one month after surgery in people with upper limb fractures (2 studies, 148 participants; very low-certainty evidence) because of substantial unexplained statistical heterogeneity. Using a 10-point visual analogue scale, one study reported less pain with LIPUS (MD -1.7, 95% CI -3.03 to -0.37; 47 participants), and the effect was less precise in the other study (MD -0.4, 95% CI -0.61 to 0.53; 101 participants). We found little or no difference in skin irritation (a possible treatment-related adverse event) between groups but judged the certainty of the evidence from this small study to be very low (RR 0.94, 95% CI 0.06 to 14.65; 1 study, 101 participants). No studies reported data for functional recovery. Data for treatment adherence were inconsistently reported across studies, but was generally described to be good. Data for costs were reported for one study, with higher direct costs, as well as combined direct and indirect costs, for LIPUS use. ECSW versus control (1 study, 56 participants) We are uncertain whether ECSW reduces pain at 12 months after surgery in fractures of the lower limb (MD -0.62, 95% CI -0.97 to -0.27, favours ECSW); the difference between pain scores was unlikely to be clinically important, and the certainty of the evidence was very low. We are also uncertain of the effect of ECSW on delayed or non-union at 12 months because the certainty of this evidence is very low (RR 0.56, 95% CI 0.15 to 2.01; 1 study, 57 participants). There were no treatment-related adverse events. This study reported no data for HRQoL, functional recovery, time to return to normal activities, or time to fracture union. In addition, no data were available for adherence or cost.

AUTHORS' CONCLUSIONS

We were uncertain of the effectiveness of ultrasound and shock wave therapy for acute fractures in terms of patient-reported outcome measures (PROMS), for which few studies reported data. It is probable that LIPUS makes little or no difference to delayed union or non-union. Future trials should be double-blind, randomised, placebo-controlled trials recording validated PROMs and following up all trial participants. Whilst time to union is difficult to measure, the proportion of participants achieving clinical and radiographic union at each follow-up point should be ascertained, alongside adherence with the study protocol and cost of treatment in order to better inform clinical practice.

Preclinical Use of FGF-18 Augmentation for Improving Cartilage Healing Following Surgical Repair: A Systematic Review

OBJECTIVE

To evaluate the efficacy of fibroblast growth factor-18 (FGF-18) augmentation for improving articular cartilage healing following surgical repair in preclinical (in vivo) animal models.

DESIGN

A systematic review was performed evaluating the efficacy of FGF-18 augmentation with cartilage surgery compared with cartilage surgery without FGF-18 augmentation in living animal models. Eligible intervention groups were FGF-18 treatment in conjunction with orthopedic procedures, including microfracture, osteochondral auto/allograft transplantation, and cellular-based repair. Outcome variables were: International Cartilage Repair Society (ICRS) score, modified O'Driscoll histology score, tissue infill score, qualitative histology, and adverse events. Descriptive statistics were recorded and summarized for each included study.

RESULTS

In total, 493 studies were identified and 4 studies were included in the final analysis. All studies were randomized controlled trials evaluating in vivo use of recombinant human FGF-18 (rhFGF-18). Animal models included ovine (n = 3) and equine (n = 1), with rhFGF-18 use following microfracture (n = 3) or osteochondral defect repair (n = 1). The rhFGF-18 was delivered via intra-articular injection (n = 2), collagen membrane scaffold (n = 1), or both (n = 1). All studies reported significant, positive improvements in cartilage defect repair with rhFGF-18 compared with controls based on ICRS score (n = 4), modified O'Driscoll score (n = 4), tissue infill (n = 3), and expression of collagen type II (n = 4) (P < 0.05). No adverse events were reported with the intra-articular administration of this growth factor, indicating short-term safety and efficacy of rhFGF-18 in vivo.

CONCLUSION

This systematic review provides evidence that rhFGF-18 significantly improves cartilage healing at 6 months postoperatively following microfracture or osteochondral defect repair in preclinical randomized controlled trials.

Prognostic Factors for the Clinical Outcome after Microfracture Treatment of Chondral and Osteochondral Defects in the Knee Joint: A Systematic Review

OBJECTIVE

The objective of this study is to establish which patient and lesion characteristics are related to the clinical outcome after microfracture of cartilage defects in the knee.

STUDY DESIGN

Systematic review.

METHODS

After preregistration, PubMed, Embase, and Cochrane were searched for studies that analyzed prognostic factors for the outcome of microfracture treatment in the knee. The criteria for inclusion were outcome measured using Patient-Reported Outcome Measures (PROMs), a clinical study with ≥10 participants receiving microfracture, and a minimal follow-up period of 1 year.

RESULTS

For none of the investigated prognostic factors, effect size reporting was sufficiently homogeneous to conduct a meta-analysis. However, a majority of the included studies identified higher age, larger lesion size, longer preoperative symptom duration, and previous surgery on the ipsilateral knee, especially meniscectomy and anterior cruciate ligament reconstruction, as factors that are reported to be correlated to a less favorable outcome. A lesion location that does not include the trochlea or the patellofemoral joint and is not weightbearing, a nondegenerative mechanism of injury, and a single lesion were reported as factors that predict a favorable outcome. As to gender, body mass index, preoperative activity level, smoking, and concomitant knee surgery, the included articles were inconclusive or no effect was reported.

CONCLUSIONS

Several factors correlated with the clinical result after microfracture treatment. However, the information on the effect sizes of the influence on clinical outcome is incomplete due to poor reporting. Large-scale registries or pooling of homogeneous, well-reported data is needed to work toward prognostic models. That would be an important step toward personalized treatment.

Training drives turnover rates in racehorse proximal sesamoid bones

Focal bone lesions are often found prior to clinically relevant stress-fractures. Lesions are characterized by low bone volume fraction, low mineral density, and high levels of microdamage and are hypothesized to develop when bone tissue cannot sufficiently respond to damaging loading. It is difficult to determine how exercise drives the formation of these lesions because bone responds to mechanical loading and repairs damage. In this study, we derive steady-state rate constants for a compartment model of bone turnover using morphometric data from fractured and non-fractured racehorse proximal sesamoid bones (PSBs) and relate rate constants to racing-speed exercise data. Fractured PSBs had a subchondral focus of bone turnover and microdamage typical of lesions that develop prior to fracture. We determined steady-state model rate constants at the lesion site and an internal region without microdamage using bone volume fraction, tissue mineral density, and microdamage area fraction measurements. The derived undamaged bone resorption rate, damage formation rate, and osteoid formation rate had significant robust regression relationships to exercise intensity (rate) variables, layup (time out of exercise), and exercise 2-10 months before death. However, the direction of these relationships varied between the damaged (lesion) and non-damaged regions, reflecting that the biological response to damaging-loading differs from the response to non-damaging loading.

Cost Effectiveness of Allogeneic Umbilical Cord Blood-Derived Mesenchymal Stem Cells in Patients with Knee Osteoarthritis

OBJECTIVES

The aim of this study was to assess the cost effectiveness of allogeneic umbilical cord blood-derived mesenchymal stem cells with sodium hyaluronate (hUCB-MSC) compared with microfracture in patients with knee cartilage defects caused by osteoarthritis (OA) in South Korea.

METHODS

A partitioned survival model approach was taken consisting of five mutually exclusive health states: excellent, good, fair, poor, and death over a 20-year time horizon. Utility values were obtained from a randomized clinical trial. Cost data were extracted from a database provided by the Health Insurance Review & Assessment Service, and the utilization of healthcare services was estimated from an expert panel of orthopedic surgeons using a structured questionnaire. The incremental cost-effectiveness ratio (ICER) in terms of quality-adjusted life-years (QALY) was calculated. Deterministic and probabilistic sensitivity analyses were performed.

RESULTS

In the base case, the incremental costs of US$14,410 for hUCB-MSC therapy along with its associated QALY gain of 0.857 resulted in an ICER of US$16,812 (₩18,790,773) per QALY (95% confidence interval [CI] US$13,408-US$20,828) when compared with microfracture treatment from a healthcare payer perspective. From a societal perspective, the ICER was US$268 (₩299,255) per QALY (95% CI -US$2915 to US$3784). When using a willingness-to-pay threshold of US$22,367/QALY, the probability of hUCB being cost effectiveness compared with microfracture was 99% from the healthcare payer perspective and 100% from the societal perspective.

CONCLUSIONS

The study demonstrated that hUCB-MSC therapy was cost effective compared with microfracture when treating patients with knee OA. These findings should inform health policy decision makers about considerations for cost-effective therapy for treating knee OA to ultimately enhance population health.

Effect of osmolarity and displacement rate on cartilage microfracture clusters failure into two regimes

Articular cartilage is a poroviscoelastic (PVE) material with remarkable resistance to fracture and fatigue failure. Cartilage failure mechanisms and material properties that govern failure are incompletely understood. Because cartilage is partially comprised of negatively charged glycosaminoglycans, altering solvent osmolarity can influence PVE relaxations. Therefore, this study aims to use osmolarity as a tool to provide additional data to interpret the role of PVE relaxations and identify cartilage failure regimes. Cartilage fracture was induced using a 100 μm radius spheroconical indenter at controlled displacement rates under three different osmolarity solvents. Secondarily, contact pressure (CP) and strain energy density (SED) were estimated to cluster data into two failure regimes with an expectation maximization algorithm. Critical displacement, critical load, critical time, and critical work to fracture increased with increasing osmolarity at a slow displacement rate whereas no significant effect was observed at a fast displacement rate. Clustering provided two distinct failure regimes, with regime (I) at lower normalized thickness (contact radius divided by sample thickness), and regime (II) at higher normalized thickness. Varied CP and SED in regime (I) suggest that failure in the regime is strain-governed. Constant CP and SED in regime (II) suggests that failure in the regime is dominantly governed by stress. These regimes can be interpreted as ductile versus brittle, or using a pressurized fragmentation interpretation. These findings demonstrated fundamental failure properties and postulate failure regimes for articular cartilage.

Effects of bisphosphonates on appendicular fracture repair in rodents

The balance between osteoclastic bone resorption and osteoblastic bone formation is ultimately responsible for maintaining a structural and functional skeleton. Despite their strength, bones do break and the main cause of fractures are trauma and decreased bone mineral density as a result of aging and/or pathology that weakens the bone's microarchitecture and subsequently, its material properties. Osteoporosis is a disease marked by increased osteoclast activity and decreased osteoblastic activity tipping the remodeling balance in favor of bone resorption and can be caused by aging, glucocorticoids, disuse and estrogen-deficiency. Ultimately, this leads to brittle and weaker bones which become more prone to trauma or stress-induced fractures. The current treatment for preventing and treating osteoporotic fractures is the use of antiresorptive drugs such as bisphosphonates (BPs) and denosumab, but unfortunately, their long-term use, especially with alendronate and ibandronate, has been associated with increased risk of atypical femoral fractures (AFFs); femoral diaphyseal fractures distal to the lesser trochanter but proximal to the supracondylar flare. The purpose of this review is to examine the information that exists in the literature examining the effects of BPs on fracture repair of long bones in rodent (rat and mouse) models. The focus on rodents stems from the scientific community's unresolved need to develop small animal models to examine the molecular, cellular, tissue and biomechanical mechanisms responsible for the development of AFFs and how best they can be treated.

Simulation of Fatigue Fracture Detection of Bridge Steel Structures under Cyclic Loads

Bridge steel structures are widely used in bridge construction with the advantages of light self-weight, convenient use, and good bridge span. Steel bridges are subjected to cyclic loading for a long time during their service period, and cyclic loading has a certain influence on their fatigue resistance performance. Fatigue is a phenomenon in which the structure is subjected to cyclic loading that generates cracks, expands continuously, and eventually leads to fracture of the member. The bridge steel structure under the repeated action of vehicle load and cyclic load is caused by microcracks and will expand with time, and the bridge deck system structure is prone to fatigue damage, so fatigue fracture detection has a great impact on the safe service life of steel bridges. In this paper, the fatigue design guidelines in the relevant codes and the bridge steel structure detection model are compared and analyzed, and a neural network-based fatigue fracture detection model for bridge steel structures under cyclic loading is proposed for the study of fatigue and corrosion interactions and fatigue and fracture of steel bridges under complex stress conditions. For this purpose, in the relevant experiments, experiments are designed to detect the fatigue fracture of bridge steel structures under different cyclic loads, and the experimental results prove the effectiveness of the proposed method.

ASSERT (Acute Sacral inSufficiEncy fractuRe augmenTation): randomised controlled, feasibility trial in older people

OBJECTIVE

To determine the feasibility of designing and conducting a definitive trial to evaluate the effectiveness of sacral fracture fixation compared with non-surgical management among older people admitted with a lateral compression pelvic fragility fracture (PFF).

DESIGN

Single-site, parallel, two-arm randomised controlled feasibility trial.

SETTING

A UK tertiary centre hospital.

PARTICIPANTS

Patients aged ≥70 years who were ambulating pre-injury requiring hospital admission (within 28 days of injury) with a type 1 lateral compression PFF.

INTERVENTIONS

The intervention group received sacral fracture fixation (cement augmentation±screw fixation) within 7 days of randomisation. Routine preoperative and postoperative care followed each surgical intervention. The control group received usual care consisting of analgesia, and regular input from the medical and therapy team.

PRIMARY AND SECONDARY OUTCOME MEASURES

The feasibility outcomes were the number of eligible patients, willingness to be randomised, adherence to allocated treatment, retention, data on the completeness and variability of the proposed definitive trial outcome measures, and reported adverse events.

RESULTS

241 patients were screened. 13 (5.4%) were deemed eligible to participate. Among the eligible participants, nine (69.2%) were willing to participate. Five participants were randomised to the intervention group and four to the control group. The clinicians involved were willing to allow their patients to be randomised and adhere to the allocated treatment. One participant in the intervention group and two participants in the control group received their allocated treatment. All participants were followed up until 12 weeks post-randomisation, and had an additional safety follow-up assessment at 12 months. Overall, the proportion of completeness of outcome measures was at least 75%. No adverse events were directly related to the trial.

CONCLUSIONS

There were significant challenges in recruiting sufficient participants which will need to be addressed prior to a definitive trial.

TRIAL REGISTRATION NUMBER

ISRCTN16719542.

Hyaluronic acid as an adjunct to microfracture in the treatment of osteochondral lesions of the talus: a systematic review of randomized controlled trials

BACKGROUND

Osteochondral lesions of the talus (OLT) are common after ankle trauma. Studies have shown that bioactive substances, such as hyaluronic acid (HA), alone, or in combination, with surgical treatment could improve cartilage regeneration and repair, but the effect of HA on patient reported outcomes is unclear.

METHODS

Literature searches were performed across four databases (PubMed, SPORTDiscus, Scopus, and The Cochrane Library) for randomized controlled trials in which at least one treatment arm involved use of HA as an adjunct to microfracture to treat patients with OLT. Primary outcomes included the American Orthopaedic Foot and Ankle Society scores (AOFAS), and the Visual Analog Scale (VAS) for pain. The level of evidence and methodological quality were evaluated using the Modified Coleman Methodology Score (MCMS).

RESULTS

Three randomized studies were eligible for review with a total of 132 patients (35, 40, 57 patients, respectively) and follow-up ranged from 10.5 to 25 months. Utilization of HA at the time of microfracture resulted in greater improvement in AOFAS scores compared to microfracture alone. The pooled effect size was moderate (Standardized Mean Difference [SMD] 0.45, 95% Confidence Interval [CI] 0.06, 0.84; P = .02) and between-study heterogeneity was low (I-squared = 0%). Utilization of HA during microfracture also led to greater improvement in VAS-pain scores compared to microfracture alone. The pooled effect size was very large (SMD -3.86, 95% CI -4.75, - 2.97; P < .001) and heterogeneity was moderate (I-squared = 69%).

CONCLUSION

Hyaluronic acid injection as an adjunct to arthroscopic MF in OLT provides clinically important improvements in function and pain at short-term follow-up compared to MF alone. Future longer-term follow-up studies are warranted to investigate the durability of MF with HA for treatment of OLT.

Once daily calcium (1000 mg) and vitamin D (1000 IU) supplementation during military training prevents increases in biochemical markers of bone resorption but does not affect tibial microarchitecture in Army recruits

Basic combat training (BCT) is a period of novel physical training including load carriage resulting in higher risk of stress fracture compared to any other time during military service. Prior trials reported a 20% reduction in stress fracture incidence with Ca and vitamin D (Ca + D) supplementation (2000 mg Ca, 800 IU vitamin D), and greater increases in tibia vBMD during BCT compared to placebo. The primary objective of this randomized, double-blind, placebo-controlled trial was to determine the efficacy of a lower dose of Ca (1000 mg/d Ca, 1000 IU vit D) on PTH, bone biomarkers and tibial microarchitecture during BCT. One hundred volunteers (50 males, 50 females; mean age 21.8 ± 3.5 y) were block randomized by race and sex to receive a daily Ca + D fortified food bar or placebo. Anthropometrics, dietary intake, fasted blood draws and high resolution pQCT scans of the distal and mid-shaft tibia were obtained at the start of BCT and 8 wks later at the conclusion of training. As compliance was 98% in both treatment groups, an intent-to-treat analysis was used. At the distal tibia, total vBMD, Tb.vBMD, Tb.N, Th.Th and Tb.BV/TV increased (+1.07 to 2.12% for all, p < 0.05) and Tb.Sp decreased (0.96 to 1.09%, p < 0.05) in both treatment groups. At the mid-shaft, Ct.Pm increased (+0.18 to 0.21%, p = 0.01) and Ct.vBMD decreased (-0.48 to -0.77%, p < 0.001) in both groups. Ca + D prevented increases in CTX and TRAP, which were observed in the placebo group (group-by-time, p < 0.05). Mean circulating 25OHD, BAP, P1NP and iCa increased and PTH decreased in both treatment groups (p < 0.05). These results, in agreement with other studies, suggest that bone microarchitectural changes indicative of bone formation occur during BCT. While Ca + D supplementation at lower doses than those tested in previous studies prevented increases in biochemical markers of bone resorption in this study, there were no significant changes in bone tissue after 8 wks of Army BCT.

Cost-effectiveness analysis of arthroscopic injection of a bioadhesive hydrogel implant in conjunction with microfracture for the treatment of focal chondral defects of the knee - an Australian perspective

AIM

JointRep is a bioadhesive hydrogel arthroscopically injected to facilitate cartilage regeneration. The cost-effectiveness of JointRep with microfracture surgery compared to microfracture alone was evaluated from the Australian healthcare system perspective, in patients with symptomatic focal chondral defects (Outerbridge Grade 3 or 4) of the knee who had failed conservative treatment and were indicated for surgery.

MATERIALS AND METHODS

A de novo Markov model comprising two health states- 'Alive' and 'Dead' was developed. Model transition probability was based on the general population mortality rates. Clinical outcomes were assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, a validated patient-reported tool measuring pain, stiffness, and physical function. The utility was derived by mapping WOMAC scores to EQ-5D scores using a published algorithm. Cost inputs were based on published Australian costs from AR-DRGs, Medicare Benefits Schedule, and Prostheses List. Model outcomes included costs, Quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio (ICER). Base-case analysis was conducted for a time horizon of 3 years and a cycle length of 1 year. Cost and health outcomes were discounted at 5% per annum. Sensitivity and scenario analyses were also conducted.

RESULTS

Total QALYs were estimated to be higher for JointRep with microfracture surgery (2.61) compared to microfracture surgery alone (1.66), an incremental gain of 0.95 QALY. JointRep with microfracture surgery was associated with an incremental cost of $6,022 compared to microfracture surgery alone, thus leading to an ICER of $6,328. Results were substantially robust to varying parameters in the sensitivity analyses conducted, alternative model settings and assumptions in scenario analyses.

LIMITATIONS

The clinical inputs used in the model were based on data from short duration, non-randomized, post-market clinical trial.

CONCLUSIONS

JointRep with microfracture surgery is a cost-effective treatment option compared to microfracture alone from the Australian health care system perspective.

The Effect of Single vs Serial Platelet-Rich Plasma Injections in Osteochondral Lesions Treated With Microfracture: An In Vivo Rabbit Model

BACKGROUND

Biological adjuvants are used after a musculoskeletal injury to improve healing, decrease inflammation, and restore joint homeostasis. Work on 1 such adjuvant, platelet-rich plasma (PRP), has suggested a positive effect when introduced during cartilage repair. However, it remains unknown whether healing osteochondral injuries benefit from serial PRP injections.

PURPOSE

To evaluate the effects of serial PRP injections versus a single PRP injection on reparative cartilaginous tissue, subchondral bone remodeling, and the expression of inflammatory cytokines in joint synovium.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 48 New Zealand White rabbits were randomly assigned to receive 1 (1P), 2 (2P), or 3 (3P) PRP injections. Cylindrical full-thickness cartilage defects (2.9 × 2.9 mm) with microdrillings (0.6-mm diameter) were created on the medial condyles of both knees. PRP was injected into the right knee after closure (groups 1P, 2P, and 3P), at 2 weeks after surgery (groups 2P and 3P), and at 4 weeks after surgery (group 3P). The left knees did not receive any PRP injections. A total of 6 rabbits in each group were euthanized at 3, 6, and 12 weeks postoperatively. Cartilage repair tissue was assessed using the Goebel macroscopic and modified International Cartilage Regeneration & Joint Preservation Society (ICRS) histological scoring systems. Subchondral bone remodeling was evaluated by micro-computed tomography analysis (micro-CT). Inflammatory cytokine levels were assessed by quantitative polymerase chain reaction.

RESULTS

No significant differences were found for the mean macroscopic score between the PRP groups at 12 weeks (control, 6.1 ± 3.3; group 1P, 3.4 ± 2.7; group 2P, 4.2 ± 2.9; group 3P, 0.7 ± 1.5). All PRP groups had a significantly higher mean modified ICRS histological score compared with the control group, but no significant difference was found among the PRP groups. No significant differences were seen in outcomes for the tested micro-CT parameters or cytokine expression levels.

CONCLUSION

Serial PRP injections conferred no apparent advantage over single injections according to evaluations of the macroscopic and histological appearance of the cartilaginous tissue, subchondral bone healing, and inflammatory cytokine expression levels in the synovium.

CLINICAL RELEVANCE

The use of PRP as a biological adjuvant to bone marrow stimulation for osteochondral lesions has the potential to enhance the quality of regenerative cartilaginous tissue. We recommend only a single PRP injection if the use of PRP is indicated by the operating surgeon as an adjuvant therapy for osteochondral lesions.