Screw Removal Research Articles

The impact of abutment type on abutment screw removal torque value after experimental aging.

To evaluate the changes in abutment screw removal torque value (RTV) of anatomic, original hybrid, and non-original hybrid abutments after simulated clinical use. Ninety-three implant-abutment-crown specimens were divided into groups according to abutment types (n=31): anatomic (stock) (A), original hybrid (OH), and non-original hybrid (NOH). After the initial abutment screw tightening, the specimens were subjected to five screw tightening (insertion/removal) cycles, or to 5000 thermal cycles with 500,000 chewing cycles combined with one or five screw tightening cycles. RTV measurements and surface analysis using scanning electron microscope were performed before and after aging. The impact of abutment types and aging treatments on RTV was determined using two-way repeated measures ANOVA, data were described with mean±SD and range, whereas the differences were significant at p<0.05. A significant interaction was found between abutment types and screw tightening cycles only (p=0.036) or combined with thermomechanical aging (p<0.001) on RTV. RTV was lower in NOH than in A and OH groups after screw tightening and thermomechanical aging (p<0.05). Before aging, the NOH abutment screw was slightly more damaged than OH and A abutment screws. After aging, screw damage was more pronounced on the surfaces of hybrid abutments, and more evident in the NOH group. The abutment screw RTV of anatomic, original hybrid, and non-original hybrid abutments become significantly lower after abutments undergo screw tightening and/or thermomechanical aging cycles, with higher RTV loss in hybrid abutments, especially non-original ones.

Removal of the Metaphyseal Screw From Tension Band Constructs After Hemiepiphysiodesis: High Rates of Physeal Tethering and Subsequent Implant Removal.

Removal of the metaphyseal screw from tension band plate constructs after correction of angular deformity in patients treated with hemiepiphysiodesis has been suggested as an alternative to removing the plate and both screws. While this has the potential benefit of easier implant removal and reinsertion in the event of rebound, there is debate in the literature regarding the benefits and risks of leaving the epiphyseal screw and plate in place. Patients treated with hemiepiphysiodesis at the distal femur and/or proximal tibia with tension band plates and screws who underwent subsequent removal of the metaphyseal screw after correction were included. Charts and radiographs were reviewed for the need for metaphyseal screw reinsertion, subsequent removal of deep implants, and evidence of physeal tethering. Tethering was defined as progressive overcorrection in the treated bone segment after removal of the metaphyseal screw with the mechanical axis moving one full mechanical axis zone or more. Patients with tethering were compared with those without. A total of 215 patients with 387 limbs treated met inclusion criteria. Of those, 175 patients were treated for idiopathic genu valgum, while 40 were treated for other conditions. Fifty-nine individuals (27%) underwent replacement of the metaphyseal screw for repeat angular correction. Fifty-one percent of patients underwent secondary procedures for reasons other than metaphyseal screw reinsertion (74 symptomatic implant removal, 7 elective implant removal, 29 due to tethering). There were 44 cases of tethering in 36 patients (17%). In cases of tethering, 7 patients were treated with observation, 11 with implant removal only, 16 with hemiepiphysiodesis on the opposite side, and 2 with osteotomy. Patients with tethering were significantly younger, more likely to be male, and more likely to have had the metaphyseal screw removed more than once (P < 0.05). Removal of only the metaphyseal screw after hemiepiphysiodesis has high rates of tethering and further surgery for iatrogenic deformity correction and implant removal. This technique is not recommended. Therapeutic Level III, case-control study.

Strontium-containing mineralized phospholipid coatings improve osseointegration in osteoporotic rats.

Surface treatments play an important role in enhancing the osseointegration of Titanium (Ti) and its alloys. This study introduces a method employing biomimetic hydroxyapatite (Hap) deposition guided by molecularly organized phospholipids, affixed to the metal implant surface. Using the Langmuir-Blodgett technique, phospholipids were deposited onto Ti-screws by using CaCl2 or CaCl2/SrCl2 aqueous solution in the subphase of a Langmuir trough in the target proportion (i.e. 10 and 90 mol% of Sr2+ in relation of Ca2+) followed by immersion in phosphate buffer and in supersaturated simulated body fluid. Coating composition and morphology were evaluated using infrared spectroscopy and scanning electron microscopy, respectively, while contact angle measurements assessed coating wettability and surface energy. Randomized screws were then implanted into the tibias of healthy and osteoporotic female rats (G1: Control-Machined, G2: Hap, G3: HapSr10, G4: HapSr90). Osseointegration, assessed 60 days post-implantation, included reverse torque, fluorochrome area, bone tissue-screw contact area, and linear extent of bone-screw contact. Results, grouped by surface treatment (Machined, Hap, HapSr10, HapSr90), revealed that the deposition of Hap, HapSr10, and HapSr90 resulted in thin and rough coatings composed of hydroxyapatite (Hap) on the screw surface with nanoscale pores. The coatings resulted in increased wettability and surface energy of Ti surfaces. The minerals are chemically similar to natural bone apatite as revealed by FTIR analysis. In vivo analyses indicated higher torque values for strontium-containing surfaces in the osteoporotic group (p = 0.02) and, in the control group superior torque for screw removal on the Hap surface (p = 0.023). Hydroxyapatite-treated surfaces enhance morphology, composition, and reactivity, promoting screw osseointegration in healthy and osteoporotic female rats. The incorporation of strontium into the mineral phase has been proposed to not only stimulate osteoblast activity but also reduce osteoclastic resorption, which may explain the improved outcomes observed here in experimental osteoporotic conditions.

Clinical experience and outcomes using a commercially available micro-plating system for metabone fractures in dogs and cats: 10 cases (2019-2023).

To report the clinical experience and long-term outcome following metabone fracture stabilisation using a commercially available micro-plating system (VetKISS, 1.0-mm, IMEX Veterinary, USA). Consecutive, client-owned cats and dogs weighing <7 kg, with traumatic metabone fractures stabilised using VetKISS micro-plates were prospectively enrolled with informed owner consent. Clinical and radiographic parameters were recorded. Either short-term or long-term clinical and radiographic follow-up was required for study inclusion. Four cats and six dogs were enrolled and operated by one of two board-certified surgeons. Bodyweight ranged from 1.9 to 6.6 kg. Number of metabones fractured: all four (60%), three (30%) and two (10%). Anatomical alignment was restored for each metabone. External coaptation was not used in any case. Radiographic follow-up documented clinical or bony union in all cases. Mean time to clinical union was 51 days. One major complication (screw removal) and two minor complications (partial construct failure) were observed. All patients made a complete functional recovery at the time of documented union. Long-term follow-up was available in five cases. No lameness (evaluated independently by both surgeons) or plate sensitivity was noted. This is the first clinical evaluation of the VetKISS for metabone fracture repair, and includes long-term follow-up. Results demonstrated complete functional recovery and 100% clinical union rates in all patients, with acceptable complication rates. This system can be considered for metabone repair in patients weighing <7 kg without the use of external coaptation.

A Conservative Technique for Fractured Implant Abutment Screw Retrieval on an Internal Connection Implant: Proof of Concept.

Broken screw removal from the implant connection is a common but challenging process. Several proposed methods and technical solutions may result in unsuccessful removal; thus, a novel, more conservative, risk-free method is proposed as a first attempt. The proposal is to use a silicon restoration holder to be twisted counterclockwise on the dried surface of the broken fragment inside the implant connection. This method, within the limitations of a minimal case series, yielded 100% results; however, despite previous attempts with less conservative techniques, this approach showed no efficacy. This article aims to promote the use of silicon restoration holders as a minimally invasive first attempt at broken screw retrieval treatment before considering other options.

COMPARISON OF FIXATION USING SCREWS AND SUTURE BUTTONS IN THE TREATMENT OF DISTAL TIBIOFIBULAR DIASTASIS ASSOCIATED WITH ANKLE FRACTURES

Purpose: We aimed to compare the treatment results of fixation using screws and a suture button when treating distal tibiofibular joint diastasis combined with ankle fractures Materials and Methods: A retrospective study was conducted on 30 patients with ankle fractures who were treated with screws and 34 patients who were treated with suture buttons for distal tibiofibular joint diastasis. Postoperative clinical outcomes were evaluated using the American Orthopedic Foot and Ankle Society (AOFAS) score, and radiologic outcomes were evaluated by measuring tibiofibular clear space, tibiofibular overlap, and medial clear space on pre- and post-operative radiographs. The average length of hospital stay, whether surgery was performed to remove the internal fixation, the time of weight bearing, and whether the internal fixation was damaged were investigated. Results: One year after surgery, the average AOFAS score showed no statistically significant difference between the screw surgery group and the suture button surgery group. The averages of tibiofibular clear space, tibiofibular overlap, and medial clear space measured immediately postoperatively did not show statistically significant differences between the screw surgery group and the suture button surgery group, but the measurements taken 1 year after surgery were significantly different statistically. Screw removal surgery was performed in all cases in the screw surgery group. In the screw surgery group, there were 3 cases of screw breakage and 3 cases of surgical wound infection, and the length of hospitalization and the postoperative weight-bearing start time in the screw surgery group were longer. Conclusion: When treating distal tibiofibular joint diastasis, the screw surgery group and the suture button surgery group showed no statistically significant difference in clinical outcomes measured by AOFAS 1 year after surgery, but the suture button surgery group had better results in radiological evaluation and in complication frequency.

Investigating Surgical Removal of Plates and Screws in Patients with Maxillofacial Trauma

BACKGROUND The removal of plates and screws in maxillofacial surgery following trauma has emerged as a significant concern. Understanding the primary reasons for hardware removal is crucial to enhance patient outcomes and reduce postoperative complications. METHODS This retrospective cohort study investigated 109 patients who underwent plate and screw fixation at Shahid Rahnemoun Hospital (Yazd, Iran) from 2011 to 2021. The study included 109 patients who met the inclusion criteria. The primary outcome was to identify and classify the causes necessitating plate and screw removal, which were categorized into four main groups: Pain, Complications, Procedural Problems, and Patient-Initiated Factors. Descriptive statistics were used to summarize the data. One-way analysis of variance and Chi-square or Fisher's exact tests were employed to analyze the associations between variables. RESULTS The study population was predominantly male (74.3%), with a mean age of 35.25 ±19.47 years. The time between plate and screw insertion and removal ranged from 14 days to 3 years, while this interval in most of the patients (51.4%) was between six months to one year. The primary reasons for hardware removal were patient-initiated factors (51.4%), followed by procedural problems (24.8%), complications (11.9%), and removals due to pain (11.9%). Except for age, other studied variables were not significantly associated with the removal cause. CONCLUSIONS The high prevalence of patient-initiated removals highlights the importance of considering individual preferences and psychological factors in surgical planning. The study emphasizes the need for age-specific considerations and a focus on preventative strategies to reduce infection-related complications.

Transphyseal Hemiepiphysiodesis: Is it Truly Reversible?

Although numerous studies reported the efficacy of percutaneous epiphysiodesis using transphyseal screws (PETS) in correcting angular knee deformities, many surgeons refrained from using it in younger children because of a lack of objective evidence of reversibility. Our hypothesis is that PETS is both truly reversible and effective. Twenty-one patients aged 8 to 13 years (36 lower limbs LL) with coronal plane knee deformity were enrolled into this prospective case series from January 2021 to September 2023. Besides the routine monitoring of PETS efficacy, low dose CT knee of 32 treated physes was done 6 months after screw removal. In addition, lower limb length, mechanical lateral distal femur angle (mLDFA), and medial proximal tibial angle (MPTA) were recorded preoperatively and 6 to 17 months after screw removal for 24 LL to investigate physis behavior, technique reversibility, and resumption of bone growth after screw removal. The mean mechanical axis deviation (MAD) correction rate was 3.46mm/mo and 1.78mm/mo for genu valgum and genu varum patients, respectively. No physeal bony bars could be detected 6 months after screw removal for all patients. Out of 24 physis that underwent computerized radiography (CR) of the whole lower limb, 12 LL resumed their growth, 4 were stationary, while 8 were excluded due to inadequate calibration. A single physis showed rebound deformity, and another showed overcorrection in the genu valgum group. In addition to being a highly effective method of hemiepiphysiodesis, PETS was found to be reproducible, safe, and reversible when used in the juvenile and early adolescent pediatric population. IV-Prospective case series.

Is There Any Purpose in Routine Syndesmotic Screw Removal? Systematic Literature Review.

Introduction: The aim of this systematic review is to examine the recent evidence comparing the removal and non-removal of syndesmotic screws in tibiofibular syndesmosis injuries in terms of functional, clinical, and radiographic outcomes. Methods: A comprehensive literature review was conducted to identify clinical studies on syndesmotic screw removal and its outcomes, searching the Cochrane Library and PubMed Medline for publications from 1 January 2004 to 12 February 2024. Studies were included if they involved tibiofibular syndesmotic screw fixation, assessed screw removal or retention, described clinical outcomes, and were original research with at least fifteen patients per group. Results: Most reviewed articles (18 out of 27; 67%) found no significant differences between the routine removal and retention of syndesmotic screws post-fixation. Four retrospective studies (15%) suggested that retaining screws might result in worse outcomes compared to removal. Two studies (7%) indicated that removing screws could introduce additional risks. One study (4%) observed that post-removal, there is some fibula-tibia separation without affecting the medial clear space. Another study (4%) noted that intraosseous screw breakage might increase the need for implant removal due to pain. Additionally, no significant differences in ankle function were found among groups with varying intervals of screw removal. Conclusions: The current literature does not definitively support routine removal of syndesmotic screws. Given the potential complications and financial costs, routine removal should not be performed unless specifically indicated.

How difficult is titanium plate and screw implant removal? A retrospective case series

IntroductionTitanium implants are commonly used for surgical fixation in orthopedic trauma, and have many benefits compared to stainless steel implants. Despite these benefits, some orthopedic surgeons remain hesitant to use titanium implants due to concerns of difficulty with future implant removal, given concerns with cold-welding and screw strippage. The objective of this study was to assess difficulties associated with titanium plate and screw implant removal. MethodsThis is a retrospective case series from a large hospital system. Patients were identified using Current Procedural Terminology (CPT) code 20,680 from 2017 to 2020. Patients were included if they had removal of titanium plate and screws from the upper or lower extremity, were at least18 years of age, and considered skeletally mature. The ease of titanium plate/screw removal was determined by assessing for implant cold-welding, broken screws, stripped screws, and the need for advanced tools (screw removal set, trephine, burr). Results157 patients were identified, with a mean age of 54 years and 59 % female. In total 1274 screws were removed: 14 (1.1 %) were stripped, 8 (0.6 %) were cold-welded, 42 (3.3 %) were loose, and 13 (1.0 %) were broken. 183 plates were removed in total, and 15 (8.2 %) had bone overgrowth that required removal. 12 (7.6 %) procedures were complicated and required the use of advanced tools. Complicated implant removal operations occurred after significantly longer in vivo implant time (mean of 3.7 vs. 1.1 years, p = 0.036), were associated with a younger age, were more likely to occur in lower extremity procedures (p = 0.034), and took significantly longer time for removal (95 vs. 42 min, p < 0.001). ConclusionsDespite concerns with titanium implants, we found a low rate of screw strippage, breakage, and cold welding during the removal process. However, 7.6 % of the 157 surgeries required additional tools other than just a screwdriver, and needed additional operative time. This information allows treating surgeons to plan for implant removal when titanium implants have been used for fixation. Level of evidenceIV

Biomechanical Analysis of Pedicle Screw Reinsertion Along the Same Trajectory in a Validated 3D-Printed Synthetic Bone Model

To investigate the biomechanical properties of pedicle screw reinsertion along the same trajectory in a previously validated synthetic bone model. Twenty identical acrylonitrile butadiene styrene models of lumbar vertebrae were three-dimensional-printed. Screws were placed in the standard fashion into each pedicle. Models were separated into 2 equal groups, control and experimental. Experimental group screws were completely removed from their testing block and reinserted once. All screws in both groups were then forcibly removed. Continuous torque monitoring was collected on screw insertion torque (IT), removal torque, and reinsertion torque. Pullout strength (PO), screw stiffness (STI), and strain energy (STR) were calculated. There was no significant difference between control and experimental groups for PO (P=0.26), STI (P=0.55), STR (P=0.50), or IT (P=0.24). There was a significant decrease in reinsertion torque (54.5 N-cm±8.2 N-cm) from control IT (62.9 N-cm±8.4 N-cm, P=0.045) and experimental IT (67.5 N-cm±7.6 N-cm, P=0.0026). Strong correlations (Pearson's r>0.80) were seen between control IT against STR and PO, between each of the experimental torque measurements, and between experimental PO and STI. Despite a significant decrease in insertion torque, there is no significant loss of pedicle screw performance when a screw is removed and reinserted along the same trajectory.

Comparative Analysis of Internal Tapered Implant-Abutment Connections: Evaluating the Morse Effect.

The purpose of the present study was to evaluate the Morse effect of different internal tapered implant-abutment connections (ITCs) using a pullout test. Implants with different ITCs were selected: Short (Bicon, USA), G1; Novo Colosso (Medens, Brazil), G2; Epkut (SIN, Brazil), G3; Strong SW (SIN, Brazil), G4; Flash (Conexão, Brazil), G5 and Bone Level (Straumann, Switzerland), G6. The respective computer-aided design (CAD) files were loaded into the analysis software to measure each ITC's taper angle and implant-abutment contact area. Six implants from each group were embedded in acrylic resin blocks, and the respective universal abutments were fixed using a mallet (G1) or by applying 20 Ncm of torque (G2 to G6). After 10 minutes, each abutment's retention screw was removed, and the force necessary for abutment rupture was recorded using a universal testing machine at a crosshead speed of 0.5 mm/min. The groups were compared using a one-way analysis of variance and Tukey's test. Spearman's correlation was used to check the correlation of the taper angle and contacting area with the pullout strength. G1, a no-screw abutment with a 3° taper, and G2, a 10° tapered abutment tightened by 20 Ncm, presented the highest pullout strength (P < .05). The increased taper angle of G4, compared to G3, reduced the Morse effect despite their similar implant-abutment contacting areas (P < .05). The G5 and G6 abutments loosened after screw removal and did not exhibit pullout resistance. The closer the tapered angle (r = -.958) and the higher the implant-abutment contact area (r = .880), the higher the pullout strength (P < .001). Within the limits of this study, the Morse effect is different among tapered implant-abutment connections. The closer the tapered angle and the higher the interface area, the higher the Morse effect between the abutment and the implant.

Post-treatment Functional Outcomes of Distal Tibiofibular Syndesmosis Injuries With Varying Duration and Method of Stabilization

The purpose of this study was to assess whether the type and duration of screw fixation affects ankle joint functional scores and patient activity levels. We evaluated 55 patients who had undergone surgical treatment for ankle fracture with concomitant distal tibiofibular syndesmosis injury. The follow-up period ranged from 2 years to 4 years and 2 months (mean 36 months). Depending on the time of screw removal, patients were divided into 2 groups (the 8–15-week group-19 patients, and the 16–22-week group-36 patients). There were 17 patients with tricortical and 38 patients with quadricortical syndesmosis fixation. The following parameters were assessed: range of motion, rates of complications, level of pain in visual analogue scale (VAS), and function. In the quadricortical fixation group the range of plantar flexion p = .04 and adduction p = .043 were significantly lower in the operated than in the nonoperated limb. In the patients who had their syndesmotic screws removed after 16–22 weeks, the range of plantar flexion in the operated limb was significantly lower than that in the nonoperated limb. We observed no differences between the evaluated groups in terms of ankle joint mobility, VAS pain levels, functional outcomes, or complication rates. All the analyzed subgroups showed poorer ranges of some types of motion in the ankle and worse functional scale and VAS pain scores after treatment in comparison with those before the injury. We suggest removing the syndesmotic screws after 8–15 weeks, due to the possibility of earlier rehabilitation, faster return to work and physical activity and less burden on the health care system. Tricortical or quadricortical syndesmosis fixation is at the surgeon's discretion.

Five-Year Results of the Salto XT Revision Ankle Arthroplasty.

The treatment of failed ankle replacements is debated, and little is published about the medium- and long-term results of revision implants. We wanted to examine prosthesis survival and physical function at least 5 years after insertion of the Salto XT revision prosthesis. All consecutive patients operated with a Salto XT revision prosthesis underwent clinical and radiologic examinations preoperatively and after 3, 12, 24, and 60 months. Complications and reoperations are described, and changes in patient-reported outcome measures and clinical scores are reported. Thirty patients were operated with a Salto XT revision prosthesis between March 2014 and March 2017. Three of these were revised (1 to a fusion and 2 to a new prosthesis), and 3 patients were reoperated with screw removal. A concurrent subtalar fusion was performed on 13 patients, and there was 1 case of likely nonunion after these procedures, but no reoperations. The mean AOFAS score increased from 39.2 (95% CI 30.8-47.5) preoperatively to 75.1 (95% CI 67.3-82.9) after 5 years, and the mean improvement was 34.2 points (95% CI 23.8-44.6). Mean EQ-5D increased from 0.36 (95% CI 0.30-0.42) preoperatively to 0.74 (95% CI 0.64-0.85) after 5 years, an improvement of 0.34 (95% CI 0.19-0.49). Radiolucent lines were present in all but 3 patients. Five-year prosthesis survival was 93% (83.6-100). This is the first study to present medium-term results of this implant. We found good improvement in outcome scores and good implant survival, but also a high prevalence of radiolucent lines.

Describing an old trick in posterior thoracal and lumbar ımplant removal surgery: follow-up results for at least 10 years

Study designRetrospective case series.ObjectivesWe aimed to describe with a novel surgical approach for the removal of posterior thoracolumbar implant in patients with symptomatic failure of the implant and present our preliminary results with this method.MethodsThis retrospective, single-center study was performed in the neurosurgery department of a university hospital. Data were gathered from the medical files of 314 patients (243 women, 77.39%; 71 men, 22.61%) with symptomatic thoracolumbar implant failure that underwent implant removal operation using our novel technique between 2010 and 2020. Symptoms, radiological findings, intraoperative findings as well as clinical outcomes were evaluated.ResultsIn our series, the average age was 46.5 years (range: 21–84) with a mean follow-up duration of 7 years (range: 3 months to 10 years). Preoperatively, the most common symptoms were leg pain and numbness of the lower extremity. Postoperatively, no major complications were noted. Clinical progression of symptoms was avoided by surgery in all patients, while we came across removal difficulties due to screw–screwdriver mismatch in 15 of 314 surgeries (4.78%). Our novel approach allowed successful screw removal including these challenging cases.ConclusionsWe suggest that our novel approach is a practical and effective for the removal of posterior thoracolumbar implant in cases with symptomatic failure attributed to screw–screwdriver mismatch. Further trials are warranted to assess the efficacy of this technique to overcome surgical problems associated with screw removal.

Early Experience With Novel Molded Allograft Anchors for the Management of Screw Loosening in Elderly Patients With Reduced Bone Density in Primary and Revision Lumbar Surgery.

Various strategies have been used to reduce pedicle screw loosening following lumbar instrumented fusion, but all strategies have limitations. In this prospective multicenter cohort study, outcomes of elderly patients with reduced bone density who underwent primary or revision fusion surgery using a novel technique of pedicle screw augmentation with demineralized bone fiber (DBF) anchors were evaluated. This study included elderly patients (aged >65 years) with dual-energy x-ray absorptiometry-confirmed reduced bone density who required lumbar pedicle screw fixation and were treated with supplemental DBF allograft anchors during primary or revision surgery. The need for DBF anchors was determined by evaluating preoperative computed tomography (CT) scans (for revision surgery) and by the surgeons' tactile feedback intraoperatively during pedicle screw insertion and removal. After determining the pedicle screw void diameter with a sizing instrument, DBF anchors and pedicle screws of the same diameter were placed into the void. CT scans were obtained on postoperative day 2 to assess pedicle breach, pedicle fracture, or anchor material extrusion and at 6 and 12 months postoperatively to assess screw loosening. Thereafter, to minimize radiation exposure, CT scans were only performed for recurrence of pain. Twenty-three patients (79% women; mean age, 74 years) received 50 lumbosacral pedicle screws augmented with DBF anchors. Most surgeries (n = 18, 78%) were revisions, and most anchors were inserted into revision pedicle screw trajectories (n = 33, 66%). Day-2 CT scans revealed no pedicle breach/fracture or extrusion of anchor material. During a mean follow-up of 15 months (12-20 months), no screw loosening was detected, and no patient required pedicle screw revision surgery. There were no adverse events attributable to DBF allografts. DBF allograft anchors appear to be safe and effective for augmenting pedicle screws during revision surgeries in female elderly patients with reduced bone density. Clinically, DBF reduced the rate of pedicle screw loosening in patients with reduced bone density. A significant reduction in screw loosening can decrease the need for revision surgeries, which are costly and carry additional risks. Enhanced bone integration from the DBF may promote better healing and long-term stability.

Vitality of autologous retromolar bone grafts for alveolar ridge augmentation after a 3-months healing period: A prospective histomorphometrical analysis.

The incorporation of retromolar bone grafts used for alveolar ridge augmentation is not well understood. This prospective observational study aims to supply histomorphometrical data from bone graft biopsies taken at the time of retrieval and after a 3-month healing period using patient-matched biopsies. In 17 patients, trephine biopsies of the graft were acquired at the time of graft retrieval and after a 3-month healing period. The biopsies were compared histomorphometrically regarding the number of osteocytes, appearance of osteocyte lacunae, quantity, surface area, and activity of the Haversian canals. All grafts appeared clinically stable after screw removal and 17 implants were placed. Histomorphometric analysis revealed no significant difference in the number of osteocytes (p = .413), osteocyte lacunae (p = .611), the ratio of filled/empty osteocyte lacunae (p = .467) and active Haversian canals (p = .495) between the biopsies retrieved after a 3-months healing period with those at the time of grafting. The only significant difference was noted in the mean surface area of the Haversian canals (p = .002). Specifically, the grafts post 3-month healing showed a significantly larger mean area (0.069 mm2) compared to the time of grafting (0.029 mm2). This study demonstrates, compared to other data, a high rate of vital structures in retromolar bone block grafts after 3 months of healing, exhibiting the same histological features in comparison to the biopsies from the native alveolar ridge. Standard histomorphometrical parameters, e.g., the amount of filled or empty osteocyte lacunae for the description of the vitality of the graft need to be reappraised.

Expandable Screws Can Increase Fixation Strength But Can They Be Removed? An in-vivo Sheep Study Demonstrating Removal Of A Novel Expandable Screw

Screw fixation failures remain clinically challenging especially hip fracture fixation in osteoporotic bone. Prior studies have shown that expandable orthopaedic screw devices can improve biomechanical fixation in bone, but concerns over their removability remains. A novel expandable screw implant has been developed that optimizes both implant fixation and removability. The present study investigated the implant removability in an animal model. A specially manufactured expandable screw implant was surgically implanted in 5 sheep for 4 months. The distal femur were extracted with the implants in-situ after euthanasia. The bone samples were scanned using micro-CT and the retraction torque of the expandable screw wings were measured to assess ease of removability. Analysis of the micro-CT images verified that bone had not grown inside the expandable screw mechanism and all expandable screw samples were removed without complication. The mean peak torque to fully retract the screws ready for removal was 0.86 Nm (0.59-1.30 Nm) and the mean peak removal torque for the retracted screws was 7.98 Nm (1.70-15.40 Nm). This large animal study result shows the feasibility of an expandable screw concept with a novel gapless design, to improve screw fixation strength mechanically, without compromising on the implant removability.

FIVE-YEAR FOLLOW-UP OF THIRD-GENERATION PERCUTANEOUS CHEVRON AND AKIN OSTEOTOMIES (PECA) FOR HALLUX VALGUS

BackgroundRecent large studies of third-generation minimally invasive hallux valgus surgery (MIS) have demonstrated significant improvement in clinical and radiological outcomes. It remains unknown whether these clinical and radiological outcomes are maintained in the medium to long-term. The aim of this study was to investigate the five-year clinical and radiological outcomes following third-generation MIS hallux valgus surgery.MethodsA retrospective observational single surgeon case series of consecutive patients undergoing primary isolated third-generation percutaneous Chevron and Akin osteotomies (PECA) for hallux valgus with a minimum 60 month clinical and radiographic follow up. Primary outcome was radiographic assessment of the hallux valgus angle (HVA) and intermetatarsal angle (IMA) pre-operatively, 6 months and ≥60 months following PECA. Secondary outcomes included the Manchester-Oxford Foot Questionnaire, patient satisfaction, Euroqol-5D Visual Analogue Scale and Visual Analogue Scale for Pain.ResultsBetween 2012 and 2014, 126 consecutive feet underwent isolated third-generation PECA. The mean follow up was 68.8±7.3 (range 60–88) months. There was a significant improvement in radiographic deformity correction; IMA improved from 13.0±3.0 to 6.0±2.6, (p &lt; 0.001) and HVA improved from 27.5±7.6 to 7.8±5.1. There was a statistically significant but not clinically relevant increase of 1.2±2.6° in the HVA between 6 month and ≥60 month radiographs. There was an increase in IMA of 0.1±1.6º between 6 month and ≥60 month radiographs which was not statistically or clinically significant. MOXFQ Index score at ≥follow up was 10.1±17.0. The radiographic recurrence rate was 2.6% at final follow up. The screw removal rate was 4.0%.ConclusionRadiological deformity correction following third-generation PECA is maintained at a mean follow up of 68.8 months with a radiographic recurrence rate of 2.6%. Clinical PROMs and patient satisfaction levels are high and comparable to other third-generation studies with shorter duration of follow up.

Rates of interlock screw back-out are high with the retrograde femoral nailing advanced system for distal femur fractures

PurposeThe retrograde femoral nailing advanced (RFNA) system (DePuy synthes) is a commonly used implant for the fixation of low distal femur and periprosthetic fractures. There is concern that the rate of distal interlock screw back-out may be higher for the RFNA compared to other nails (ON). The purpose of this study was to evaluate the incidence of interlock screw back-out and associated screw removal for RFNA versus ON, along with associated risk factors.MethodsA retrospective comparative study of patients who underwent retrograde nailing for a distal femur fracture at an academic level one trauma center was performed. The incidence of distal interlock screw back-out and need for screw removal were compared for RFNA versus a propensity score matched cohort who received other nails.ResultsOne hundred and ten patients underwent retrograde nailing with the RFNA for a distal femur fracture from 2015 to 2022 (average age: 66, BMI: 32, 52.7% smokers, 54.5% female, 61.8%). There was a significantly higher rate of interlock back-out in the RFNA group compared to the ON (27 patients, 24.5% vs 12 patients, 10.9%, p = 0.01), which occurred 6.3 weeks postoperatively. Screw removal rates for back-out were not significantly different for the RFNA group versus ON (8 patients, 7.3% vs 3 patients, 2.7%, p = 0.12).ConclusionIn this retrospective comparative study of distal femur fractures treated with retrograde nailing, the RFNA implant was associated with an increased risk of distal interlock screw back-out compared to other nails.