Purpose Three dimensional (3D) printing, also called ‘rapid prototyping’ and ‘additive manufacturing’ is considered as a “second industrial revolution.” With this rapidly emerging technology, CT or MR images are used for the creation of graspable objects from 3D reconstituted images. Patient-specific anatomical models can be, therefore, manufactured efficiently. These can enhance surgeon's understanding of their patients' patho-anatomy and also help in precise preoperative planning. The 3D printed patient-specific guides can also help in achieving accurate bony cuts, precise implant placement, and nice surgical results. Customized implants, casts, orthoses and prosthetics can be created to match an individual patient's anatomy. The 3D printing of individualized artificial cartilage scaffolds and 3D bioprinting are some other areas of growing interest. We aim to study the publication trends in 3D printing as applied to the field of orthopaedics. Materials and methods A literature search was performed to extract all papers related to 3D printing applications in orthopaedics and allied sciences on the Pubmed, Web of Science and SCOPUS databases. Suitable keywords and boolean operators (“3D Printing” OR “3-dimensional printing” OR “3D printed” OR “additive manufacturing” OR “rapid prototyping”) AND (‘‘Orthopaedics” OR “Orthopaedics’’) were used, in May 2018. Search was attempted in Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, and Database of Abstracts of Review of Effectiveness (DARE) databases, using keywords 3d printing orthopaedics. A similar search was repeated in pubmed and SCOPUS to get more specific papers. No limits were set on the period or evidence level, as 3D printing in orthopaedics is relatively new and evidence available is usually limited to low-level studies. Trends in a publication on these topics were analyzed, focussing on publications, type of research (basic science or clinical), type of publication, authors, institution, and country. Some citations received by these papers were also analyzed in SCOPUS and Web of Science. MS Excel (2008 - Mac version) and VOS Viewer1.6.8 (2018- Mac version) software were used to analyze the search results and for citation mapping respectively. We also identified top 10 most cited articles in the field. Results An increasing trend in publications in 3D printing-related work in orthopedic surgery and related fields was observed in the recent past. A search on Pubmed using the above strategy revealed 389 documents. A similar search revealed 653 documents on SCOPUS, many (314) of which were from an engineering background and only 271 were related to medicine. No papers were found in the Cochrane database. Search on TRIP database revealed 195 papers. A similar search revealed 237 papers on orthopedic applications on Pubmed and 269 documents on SCOPUS, whereas a search on Web of Science revealed only 23 papers. Publication trends were then analyzed on data derived from SCOPUS database. Overall, most papers were published from China, followed by United States, United Kingdom, and India. Conclusion There has been an upsurge of interest in 3D printing in orthopedic surgery, as is evident by an increasing trend in research and publications in this area in the recent years. Presently, 3D printing is in a primitive stage in the field of orthopedic surgery as our knowledge is still insufficient, and costs and learning curve are somewhat high. However, looking at latest publication trends, we are enthusiastic that it holds the key to future in orthopaedics and trauma cases.

Publication trends and knowledge mapping in 3D printing in orthopaedics.

One long-held tenet of total knee arthroplasty (TKA) is that post-operative neutral limb alignment promotes implant durability. Recently, the concept of generic safe zone (0° ± 3°) has been challenged. This meta-analysis aimed to evaluate whether neutral alignment was superior to malalignment in long-term survival of TKAs. The MEDLINE, Embase, Cochrane Library, China National Knowledge Infrastructure, Wan Fang Chinese Periodical, Google and reference lists of all the included studies were searched. Of the 1512 studies initially identified, ten met the eligibility criteria, including eight case–control studies and two cohort trials. Relative risks of implant failure were compared between post-operative neutrally aligned and malaligned knees. Post-operative malalignment showed higher failure rate of knee implants compared with neutral alignment (95 % CI 1.00–1.88, P = 0.05). Failure rate in knees with varus alignment was significantly higher than with neutral alignment (95 % CI 1.07–2.55, P = 0.02). There was no significant difference in the likelihood of implant failure between knees with valgus and neutral alignment (95 % CI 0.78–2.41, n.s.). No significant difference of failure rate was noted between neutral alignment and malalignment for fixed-bearing prothesis (95 % CI 0.94–1.95, n.s.) or rotating-platform prothesis (95 % CI 0.75–2.73, n.s.). There was no significant difference of failure rate between knees with neutral alignment and malalignment for studies with a mean follow-up of more than 10 years (95 % CI 0.81–2.01, n.s.) or studies using long-leg weight-bearing radiographs (95 % CI 0.79–1.79, n.s.). Post-operative varus alignment results in shorter survival rate after TKA. Not only neutral limb alignment but also the valgus alignment promotes implant durability. Neutral or valgus alignment rather than varus alignment is essential to achieve long-term survival of TKAs and patient satisfaction. III.

Shorter survival rate in varus-aligned knees after total knee arthroplasty

The purpose of the present study was to compare patient-specific instrumentation (PSI) with standard instrumentation (SI) in patients undergoing total knee arthroplasty (TKA). PSI is hypothesized to have advantages with respect to component alignment; number of outliers (defined as alignment > 3° from the target alignment); operative time; perioperative blood loss; and length of hospital stay. This new surgical technique is expected to exhibit superior performance. A total of 23 randomized controlled trials (RCTs) involving 2058 knees that compared the clinical outcomes of TKA between PSI and SI were included in the present analysis; these RCTs were identified via a literature search of the PubMed, Embase, and Cochrane Library databases through March 1, 2018. The outcomes of interest included coronal, sagittal and axial component alignment (presented as the angle of deviation from the transcondylar line); number of outliers; operative time; perioperative blood loss; and length of hospital stay. There was a significant difference in postoperative femoral axial alignment between PSI and SI patients (95% CI − 0.71 to − 0.21, p = 0.0004, I2 = 48%). PSI resulted in approximately 0.4° less deviation from the transcondylar line than SI. Based on our results, PSI reduced operative time by a mean of 7 min compared with SI (95% CI − 10.95 to − 3.75, p < 0.0001, I2 = 78%). According to the included literature, PSI reduced perioperative blood loss by approximately 90 ml compared with SI (95% CI − 146.65 to − 20.18, p = 0.01, I2 = 74%). We did not find any differences between PSI and SI with respect to any other parameters. PSI has advantages in axial alignment of the femoral component, operative time, and perioperative blood loss relative to SI. No significant differences were found between PSI and SI with respect to alignment of the remaining components, number of outliers, or length of hospital stay. Therapeutic study (systematic review and meta-analysis), Level I.

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Patient-specific instrumentation improved axial alignment of the femoral component, operative time and perioperative blood loss after total knee arthroplasty.

Objective To determine if surgical approach impacts the rate of nerve palsy after plate fixation of humerus shaft fractures and whether or not iatrogenic nerve palsy recovers in similar ways to preoperative palsy. Design Retrospective. Setting Two trauma centers. Patients Patients 18+ years of age with nonpathologic, extra-articular humerus shaft fractures (OTA/AO 12A/B/C and 13A2-3) treated with plate fixation. Intervention Plate fixation of humerus shaft fractures, from 2008 to 2016. Main outcome measurement Rate of iatrogenic nerve palsy by a surgical approach and injury characteristics. Results Two hundred sixty-one humeral shaft fractures were included. The rate of preoperative palsy was 19%. Radial nerve palsy (RNP) was present in 18%. Iatrogenic RNP occurred in 12.2% and iatrogenic ulnar palsy in 1.2%. Iatrogenic palsy occurred in 15.6% of middle and 15% of distal fractures, with fracture location significantly different in those developing RNP (P = 0.009). Iatrogenic RNP occurred in 7.1% of anterolateral, 11.7% of posterior triceps-splitting, and 17.9% of posterior triceps-sparing approaches (P = 0.11). Follow-up data were available for 139 patients at an average of 12 months. Preoperative RNP resolved less often than iatrogenic RNP, in 74% versus 95% (P = 0.06). Time to resolution was longer for preoperative RNP, at 5.5 versus 4.1 months (P = 0.91). Twenty-two percent with preoperative RNP underwent tendon transfer or wrist fusion, versus 0% after iatrogenic RNP (P = 0.006). Conclusion Iatrogenic RNP is not uncommon with humeral fracture fixation and occurs at similar rates in anterior and posterior approaches and with midshaft and distal fractures. Iatrogenic RNP had a high rate of recovery. Preoperative RNP more often requires surgery for unresolved palsy. Level of evidence Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Iatrogenic Nerve Palsy Occurs With Anterior and Posterior Approaches for Humeral Shaft Fixation.

Humeral shaft fractures are often associated with radial nerve palsy (RNP) (8–16%). The primary aim of this systematic review was to assess the incidence of primary and secondary RNP in closed humeral shaft fractures. The secondary aim was to compare the recovery rate of primary RNP and the incidence of secondary RNP between operative and non-operative treatment. A systematic literature search was performed in ‘Trip Database’, ‘Embase’ and ‘PubMed’ to identify original studies reporting on RNP in closed humeral shaft fractures. The Coleman Methodology Score was used to grade the quality of the studies. The incidence and recovery of RNP, fracture characteristics and treatment characteristics were extracted. Chi-square and Fisher exact tests were used to compare operative versus non-operative treatment. Forty studies reporting on 1758 patients with closed humeral shaft fractures were included. The incidence of primary RNP was 10%. There was no difference in the recovery rate of primary RNP when comparing operative treatment with radial nerve exploration (98%) versus non-operative treatment (91%) (p = 0.29). The incidence of secondary RNP after operative and non-operative treatment was 4% and 0.4%, respectively (p   90% recovers without the need of (re-)intervention. No beneficial effect of early exploration on the recovery of primary RNP could be demonstrated when comparing patients managed non-operatively with those explored early. Patients managed operatively for closed humeral shaft fractures have a higher risk of developing secondary RNP. Level IV; Systematic Review.

https://link.springer.com/content/pdf/10.1007/s00402-020-03446-y.pdf

Radial nerve palsy associated with closed humeral shaft fractures: a systematic review of 1758 patients.

Management of extra-articular distal humerus fractures presents a challenge to the treating surgeon due to the complex anatomy of the distal part of the humerus and complicated fracture morphology. Although surgical treatment has shown to provide a more stable reduction and alignment and predictable return to function, it has been associated with complications like iatrogenic radial nerve palsy, infection, non-union and Implant failure. We in the present series retrospectively analysed 20 patients with extra-articular distal humerus shaft fractures surgically treated using the extra-articular distal humeral locking plate approached by the triceps-sparing posterolateral approach. The outcome was assessed using the DASH score, range of motion at the elbow and the time to union. The mean time to radiographic fracture union was 12 weeks.

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Retrospective analysis of extra-articular distal humerus shaft fractures treated with the use of pre-contoured lateral column metaphyseal LCP by triceps-sparing posterolateral approach

Introduction : Coronal plane distal humeral injuries are relatively rare. Numerous classification systems have been proposed as the complexity of these fractures has been realized. We in the present series of ten patients describe the surgical technique of Open Reduction and Internal Fixation of Coronal plane fractures of the distal humerus with headless compression screws performed using the anterolateral approach.Material and method : It was a retrospective study, the data collected from March 2010 to 2015 was analysed and the final outcome was assessed using the DASH score. Out of a total of 13 patients with distal humerus coronal plane fractures, 10 patients were available for follow up. The X-rays and CT scans were reviewed and the fractures were classified according to Dubberley and Bryan and Morrey classification. Radiographic were evaluated for presence of union or nonunion, avascular necrosis, joint line step-off (none/1-mm/>1-mm), hardware failure and instability.Results : The average age was 41 years. The average DASH score in our study was around 24. The time to union ranged between 8–12 weeks with the average time being around 10 weeks. One patient had post traumatic Arthritis radiologically classified as Broberg and Morrey Type 2 and one patient had Heterotrophic ossification Brooker Grade 1.Conclusion : Open reduction and internal fixation of coronal shear fractures of capitellum and trochlea using headless screw compression via the antero-lateral approach is a reliable treatment modality and results in stable fixation with restoration of a functional arc of motion.Level of evidence : IV

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Retrospective analysis of open reduction and internal fixation of coronal plane fractures of the capitellum and trochlea using the anterolateral approach

Introduction Restoration of mechanical axis (MA) is one of the most important aims of treatment of knee arthritis. The measurement of MA is often done on hip knee ankle (HKA) radiographs (LLR), but its measurement is often difficult and variable. We studied to check if inter-observer variability in the measurement of MA is dependent on the experience of the observer. Materials and methods 48 patients (70 knees) underwent measurement of MA on HKA radiographs. The measurement was done by five observers of different experience. All the results were tested for inter-observer variability. Results The overall intra-class correlation was 0.70. The two full time consultants had good agreeability among them ( p p values >0.005). All the other groups (except senior consultant and senior registrar) had statistically significant difference amongst them (all p values Conclusion There is an inter-observer variability in the measurement of MA on the HKA radiographs. The agreeability between the observers increases as the experience of the personnel increases. Although long leg radiographs can be used for assessment for HKA, this variability should be kept in mind while using this as a tool for planning management of the arthritic knee.

Inter-observer variability and its correlation to experience in measurement of lower limb mechanical axis on long leg radiographs

Computerized tomography based “patient specific blocks” improve postoperative mechanical alignment in primary total knee arthroplasty

Computerized tomography based "patient specific blocks" improve postoperative mechanical alignment in primary total knee arthroplasty.

Steroid induced osteonecrosis of the femoral head is commonly seen in clinical practice, but yet not fully understood. It is intriguing why only some cases develop and others escape from it. We did an extensive and up to date literature review on it, with the aim to identify its incidence, associated risk factor and pathogenesis. We found that the incidence ranged from 03 to 40%, and was more with associated risk factors. Several risk factors were identified, which included higher dose and prolonged duration of steroid consumption, and underlying disease for which the steroids were given. Pathogenesis of this disease is complex and not yet fully understood. Awareness about this condition and associated risk factors should help the clinicians in identifying the cases who are prone to develop osteonecrosis with the use of steroids.

Vikas Birla

Papers

Retrospective analysis of extra-articular distal humerus shaft fractures treated with the use of pre-contoured lateral column metaphyseal LCP by triceps-sparing posterolateral approach

Retrospective analysis of open reduction and internal fixation of coronal plane fractures of the capitellum and trochlea using the anterolateral approach

Inter-observer variability and its correlation to experience in measurement of lower limb mechanical axis on long leg radiographs

Computerized tomography based "patient specific blocks" improve postoperative mechanical alignment in primary total knee arthroplasty.

Risk factors and pathogenesis of steroid-induced osteonecrosis of femoral head - A scoping review