Internal fixation: a historical review

Comparison of bioabsorbable screw versus metallic screw fixation for tibial tubercle fractures in adolescents: a retrospective cohort study

BACKGROUND

Displaced tibial tubercle (TT) fractures in adolescents are typically treated with open reduction and internal fixation. While metallic screw (MS) fixation provides strong stability, it often results in a high incidence of postoperative screw head protrusion or irritation, leading to additional removal surgery. Bioabsorbable screw (BS) fixation presents an alternative that may avoid these issues, though its stability has not yet been extensively documented in the literature. This study aims to compare the efficacy of BS versus MS in the fixation of TT fractures.

METHODS

A retrospective analysis was conducted on adolescent patients with TT fractures who underwent surgical treatment from September 2015 to September 2023. Patients were divided into two groups based on the fixation method: The BS group and the MS group. Data collected included patient demographics, fracture details, treatment strategies, radiological and clinical rehabilitation outcomes, and postoperative complications. Knee joint function was evaluated using the Lysholm and Tegner scores. Statistical analysis was performed to identify differences between the variables of the two groups.

RESULTS

A total of 30 patients with 32 fractures were included, with 15 fractures in the BS group and 17 in the MS group. The average follow-up period was 42.1 (range: 12.0-109.5) months. The demographic characteristics, fracture details, and treatment strategies were comparable between the two groups. No significant differences were observed between the groups in fracture healing time, time to return to pre-injury activities, or knee joint function as assessed by the Lysholm and Tegner scores at the final follow-up. However, compared with the MS group, the BS group showed a shorter time to regain full range of motion (ROM) in the knee joint and experienced lower rates of postoperative hardware irritation and joint stiffness.

CONCLUSIONS

Both BS and MS fixations are safe and effective for treating adolescent TT fractures. BS fixation has the advantages of avoiding hardware irritation, facilitating earlier recovery of knee joint ROM, reducing the incidence of joint stiffness, and eliminating the need for additional removal surgery.

CLINICAL TRIAL NUMBER

Not applicable.

The Metal in My Body: Patients' Perception and Attitude Toward Orthopedic Implants

INTRODUCTION

Metal implants are broadly used in orthopedics and traumatology to stabilize bone fragments. This study aimed to explore patients' awareness, body image, and overall experience of living with a metal implant after a fracture.

METHODS

A mixed methods convergent design (QUAN+QUAL) was adopted. A self-reported 30-item questionnaire was used to investigate patients' perception and apprehension of the implantation of orthopedic materials. To enlighten the quantitative findings, semi-structured interviews followed till data saturation. Quantitative and qualitative data were compared during the analysis phase.

RESULTS

Results showed that women's and elders' acceptance of the implants was greater than that of men and younger patients even in acute cases. The sense of superiority provided by the implant was mainly reported by the elderly (adjusted odds ratio (ORadj) for increasing age: 1.06; 95% CI: 1.02-1.1; p<0.01), and the sense of inferiority was mainly reported by young men (ORadj: 6.19; 95% CI: 2.36-16.22; p<0.01). Similarly, women and elderly mostly tended to answer that the injured limb felt stronger after the implant placement, while young men tended to answer a sense of weakness with the implant (ORadj for increasing age: 1.06; 95% CI: 1.03-1.09; ORadj for male gender: 4.67; 95% CI: 1.87-11.7; p<0.01 for both regressions). Most participants (56.6%) and mainly young participants, regardless of gender, expressed the desire to get the metal implants removed (ORadj for increasing age: 0.91; 95% CI: 0.89-0.95; p<0.01). Misinformation and misconception were also found in a high percentage of the questioned patients (48.1%). Thematic analysis of the interviews revealed that none of the participants directly attributed any change in their life, self, or body image to the implants. An altered body image was not reported. The most reported experience was the restriction of movement due to the accident or the subsequent physical weakness.

CONCLUSION

Despite the acceptance of the implant being great, the level of patient knowledge was fairly low. The present study highlights the importance of providing patients with information throughout their management to avoid misunderstandings. Age and gender did influence patients' perception of the implants. Personalized assessment is further needed to address body image issues after an implant placement procedure.

Magnesium implants in orthopaedic surgery create a diagnostic conundrum: A radiology case series and literature review

During a routine post-operative orthopaedic radiograph reading session, repeated unusual radiographic soft tissue and bone appearances became evident. It was discovered that these patients had received biodegradable magnesium implants which have recently been introduced into orthopaedic clinical practice. To the untrained eye, the combination of peri-metallic bone resorption with associated soft tissue gas, could easily be mistaken for post-operative infection. The aim of this study is to properly characterise the radiographic post-operative appearances of biodegradable magnesium orthopaedic hardware. We retrospectively evaluated radiographs of all patients who underwent magnesium screw implantation for fractures over a 6 month period. Four patients, mean age of 9.75 (range: 6-15) years who underwent magnesium screw fixation following fracture were included in the study. Follow up duration was 100 days (range: 75-122) with a mean of 2.5 postoperative radiographs being performed per patient during this period. All cases demonstrated post-operative peri-metallic radiolucency which developed around the magnesium screws on x-ray, which subsequently resorbed over time. Peri-metallic soft tissue gas was observed in all patients. In two cases, magnesium implants fractured. As the use of biodegradable metal implants becomes more common, it is important for radiologists to be aware of their imaging characteristics. Prior to reporting a case, it would be prudent to know if biodegradable screws have been utilised and whether there exists a clinical concern for post-operative infection in patients with these particular implants, in which case it would be critical not to dismiss peri-prosthetic radiolucencies and soft tissue gas as merely a sequela of the natural metal degradation process.

Investigation of Biomechanical Characteristics of Orthopedic Implants for Tibial Plateau Fractures by Means of Deep Learning and Support Vector Machine Classification

An experimental comparative study of the biomechanical behavior of commonly used orthopedic implants for tibial plateau fractures was carried out. An artificial bone model Synbone1110 was used and a Schatzker V type tibial plateau fracture was created in vitro, then stabilized with three different implant types, classic L plate, Locking Plate System (PLS), and Hybrid External Fixator (HEF). The stiffness of the bone—implant assembly was assessed by means of mechanical testing using an automated testing machine. It was found that the classic L plate type internal implant has a significantly higher value of deformation then the other two implant types. In case of the other implant types, PLS had a better performance than HEF at low and medium values of the applied force. At high values of the applied forces, the difference between deformation values of the two types became gradually smaller. An Artificial Neural Network model was developed to predict the implant deformation as a function of the applied force and implant device type. To establish if a clear-cut distinction exists between mechanical performance of PLS and HEF, a Support Vector Machine classifier was employed. At high values of the applied force, the Support Vector Machine (SVM) classifier predicts that no statistically significant difference exists between the performance of PLS and HEF.

Hybrid fracture fixation systems developed for orthopaedic applications: A general review

Orthopaedic implants are applied daily in our orthopaedic clinics for treatment of musculoskeletal injuries, especially for bone fracture fixation. To realise the multiple functions of orthopaedic implants, hybrid system that contains several different materials or parts have also been designed for application, such as prosthesis for total hip arthroplasty. Fixation of osteoporotic fracture is challenging as the current metal implants made of stainless steel or titanium that are rather rigid and bioinert, which are not favourable for enhancing fracture healing and subsequent remodelling. Magnesium (Mg) and its alloys are reported to possess good biocompatibility, biodegradability and osteopromotive effects during its in vivo degradation and now tested as a new generation of degradable metallic biomaterials. Several recent clinical studies reported the Mg-based screws for bone fixation, although the history of testing Mg as fixation implant was documented more than 100 years ago. Truthfully, Mg has its limitations as fixation implant, especially when applied at load-bearing sites because of rather rapid degradation. Currently developed Mg-based implants have only been designed for application at less or non-loading-bearing skeletal site(s). Therefore, after years research and development, the authors propose an innovative hybrid fixation system with parts composed of Mg and titanium or stainless steel to maximise the biological benefits of Mg; titanium or stainless steel in this hybrid system can provide enough mechanical support for fractures at load-bearing site(s) while Mg promotes the fracture healing through novel mechanisms during its degradation, especially in patients with osteoporosis and other metabolic disorders that are unfavourable conditions for fracture healing. This hybrid fixation strategy is designed to effectively enhance the osteoporotic fracture healing and may potentially also reduce the refracture rate. The translational potential of this article: This article systemically reviewed the combination utility of different metallic implants in orthopaedic applications. It will do great contribution to the further development of internal orthopaedic implants for fracture fixation. Meanwhile, it also introduced a titanium-magnesium hybrid fixation system as an alternative fixation strategy, especially for osteoporotic patients.

A cohort study of 4,190 patients treated with low-intensity pulsed ultrasound (LIPUS): findings in the elderly versus all patients

BACKGROUND

Patient age is one of many potential risk factors for fracture nonunion. Our hypothesis is that older patients (≥ 60) with fracture risk factors treated with low-intensity pulsed ultrasound (LIPUS) have similar heal rate (HR) to the population as a whole. We evaluate the impact of age in conjunction with other risk factors on HR in LIPUS-treated patients with fresh fracture (≤ 90 days old).

METHODS

The Exogen Bone Healing System is a LIPUS device approved in 1994 to accelerate healing of fresh fracture. After approval, the FDA required a Post-Market Registry to assess performance. Patient data collected from October 1994 until October 1998 were individually reviewed and validated by a registered nurse. Four distinct data elements were required to report a patient: date fracture occurred; date treatment began; date treatment ended; and a dichotomous outcome of healed v. failed, by clinical and radiological criteria. Data were used to calculate two derived variables; days to treatment (DTT) and days on treatment (DOT). Every validated fresh fracture patient with DTT, DOT, and outcome is reported.

RESULTS

The validated registry had 5,765 patients with fresh fracture; 73% (N = 4,190) are reported, while 13% of patients were lost to follow-up, 11% withdrew or were non-compliant, and 3% died or are missing outcome. Among treatment-compliant patients, HR was 96.2%. Logistic estimates of the odds ratio for healing are equivalent for patients age 30 to 79 years and all age cohorts had a HR > 94%. Open fracture, current smoking, diabetes, vascular insufficiency, osteoporosis, cancer, rheumatoid arthritis, and prescription NSAIDs all reduced HR, but older patients (≥ 60) had similar HRs to the population as a whole. DTT was significantly shorter for patients who healed (p < 0.0001).

CONCLUSIONS

Comorbid conditions in conjunction with aging can reduce fracture HR. Patients with fracture who used LIPUS had a 96% HR, whereas the expected HR averages 93%. Time to treatment was significantly shorter among patients who healed (p < 0.0001), suggesting that it is beneficial to begin LIPUS treatment early. Older patients (≥ 60) with fracture risk factors treated with LIPUS exhibit similar heal rates to the population as a whole.