Critical loss of primary implant stability in osteosynthesis locking screws under cyclic overloading.

Primary implant stability, which refers to the stability of the implant during the initial healing period is a crucial factor in determining the long-term success of the implant and lays the foundation for secondary implant stability achieved through osseointegration. Factors affecting primary stability include implant design, surgical technique, and patient-specific factors like bone quality and morphology. In vivo, the cyclic nature of anatomical loading puts osteosynthesis locking screws under dynamic loads, which can lead to the formation of micro cracks and defects that slowly degrade the mechanical connection between the bone and screw, thus compromising the initial stability and secondary stability of the implant. Monotonic quasi-static loading used for testing the holding capacity of implanted screws is not well suited to capture this behavior since it cannot capture the progressive deterioration of peri­implant bone at small displacements. In order to address this issue, this study aims to determine a critical point of loss of primary implant stability in osteosynthesis locking screws under cyclic overloading by investigating the evolution of damage, dissipated energy, and permanent deformation. A custom-made test setup was used to test implanted 2.5 mm locking screws under cyclic overloading test. For each loading cycle, maximum forces and displacement were recorded as well as initial and final cycle displacements and used to calculate damage and energy dissipation evolution. The results of this study demonstrate that for axial, shear, and mixed loading significant damage and energy dissipation can be observed at approximately 20 % of the failure force. Additionally, at this load level, permanent deformations on the screw-bone interface were found to be in the range of 50 to 150 mm which promotes osseointegration and secondary implant stability. This research can assist surgeons in making informed preoperative decisions by providing a better understanding of the critical point of loss of primary implant stability, thus improving the long-term success of the implant and overall patient satisfaction.

Scapula fractures: functional anatomy, clinical assessment and management.

Fractures of the scapula are rare injuries, accounting for 3-5% of all shoulder girdle fractures. They are frequently the result of high energy trauma and often present with concurrent and life-threatening injuries to adjacent structures, leading to significant morbidity and mortality. Patients presenting with scapula fractures must receive a thorough and systematic clinical assessment as directed by national trauma guidelines. Appropriate imaging is essential in delineating fracture morphology and should at the very least include anteroposterior, anteroposterior oblique (Grashey) and axillary or scapula 'Y' view of the shoulder. Computed tomography imaging with three-dimensional reconstruction allows better delineation of the fracture morphology and helps with surgical planning. A lack of randomised controlled trials comparing the efficacy of conservative and operative management of scapula fractures has resulted in limited consensus for surgical indications. Nevertheless, most extra-articular fractures can be managed conservatively while intra-articular fractures of the glenoid frequently require surgical fixation.

Functional and union outcome of combined column tibial plateau fracture treated with hybrid external fixator.

Objective: To determine the combined column tibial plateau fracture treated with a hybrid external fixator in terms of knee functionality, union outcome and complications. METHODS: The quasi-experimental study was conducted at the Department of Orthopaedic Surgery, Mayo Hospital, Lahore, Pakistan, from July 5, 2019, to December 31, 2021, and comprised patients of either gender aged 20-50 years who presented with 2-column or 3-column fractures of proximal tibia classified according to the 3-column classification system after being diagnosed using radiographs and three-dimensional computed tomography scan. Knee function, union and complications, like neural, vascular, infection, delayed union, nonunion, malunion and implant failure, were evaluated. The Knee Society Score was used to assess knee function, and modified Rasmussen score for the union, while complications were assessed clinically on the 2nd, 6th, 12th, 16th, 24th, 36th weeks and one year post-operatively. Data was analysed using SPSS 26. RESULTS: Of the 113 patients, 91(80.53%) were males and 22(19.47%) were females. The overall mean age was 35.56±9.00 years. From the 12th week to the 24th week 45(39.83%) patients had good and 59(52.21%) patients had excellent functional outcomes. Union outcome in the 16th and 24th week was good in 57(50.44%) patients and excellent in 47(41.59%) patients. No neurovascular injury was observed. Superficial pin tract infection was observed in 21(18.6%) cases that healed with wound debridement and antibiotics. No delayed union, malunion and implant failure was observed. CONCLUSIONS: Good to excellent functional and union outcomes with minimum complications were observed with the hybrid external fixator.

Radiographic and clinical outcomes of muenster and sugar tong splints for distal radius fractures: a comparative study.

BACKGROUND: Non-operative management is typically indicated for extra-articular distal radius fractures. Conservative treatments such as Sugar tong splints (STs) and Muenster splints (MUs) are commonly used. However, there is limited research and outcome data comparing the two splint types. Therefore, this study aimed to investigate and compare the radiographic and clinical outcomes of treatment using STs and MUs. METHODS: In this retrospective comparative study, we aimed to evaluate and compare the radiographic and clinical outcomes of STs and MUs for the treatment of distal radius fractures. The study included 64 patients who underwent closed reduction (CR) in the emergency room and were treated with either STs or MUs splints (STs group: n = 38, MUs group: n = 26). Initial X-rays, post-CR X-rays, and last outpatient follow-up X-rays were evaluated. Radial height (RH), ulnar variance (UV), radial inclination (RI), and volar tilt (VT) were measured by a blinded investigator. The Quick DASH form was applied to measure patients' satisfaction after treatments. RESULTS: There were no significant differences in baseline characteristics, initial radiographic measurements, or radiographic measurements immediately after CR between the two groups. However, the overall radiological values deteriorated to some degree in both groups compared to the post-CR images. Furthermore, using a paired test, the STs group showed significant differences in RH and RI, and the MUs group showed significant differences in RH and UV between the last follow-up and post-CR images. CONCLUSIONS: The study concluded that there was no difference in clinical outcomes between the two splint types. However, both STs and MUs groups showed reduced radiographic parameters, and the MUs group showed a significant reduction of RH and UV in the treatment of distal radius fractures. LEVEL OF EVIDENCE: Level IV; Retrospective Comparison; Treatment Study.

[Comparison of effectiveness of three surgical methods in treatment of Pauwels type â ¢ femoral neck fracture in young and middle-aged patients].

Objective: To compare the effectiveness of three surgical methods in the treatment of Pauwels type Ⅲ femoral neck fracture in young and middle-aged patients, in order to provide reference for clinical selection of appropriate surgical methods. Methods: The clinical data of 103 patients with Pauwels type Ⅲ femoral neck fracture who met the selection criteria between June 2018 and December 2021 were retrospectively analyzed. The fractures were fixed with hollow screws in an inverted triangular shape (37 cases, hollow screw group), hollow screws in an inverted triangular shape combined with eccentric shaft screw (34 cases, eccentric shaft screw group), and hollow screws in an inverted triangular shape combined with medial support plate (32 cases, support plate group). There was no significant difference in age, gender, cause of injury, body mass index, time from injury to operation, side of the fracture, and Garden classification, whether they were in traction preoperatively, and other baseline data between groups ( P>0.05). The operation time, intraoperative blood loss, the number of fluoroscopy, the length of hospital stay, early postoperative complication and postoperative weight-bearing time of the three groups were recorded. Harris score was used to evaluate joint function at 6 and 12 months after operation, and the difference between the two time points (change value) was calculated for comparison between groups. X-ray films were reviewed to evaluate the quality of fracture reduction (Garden index) and healing, as well as the occurrence of internal fixation failure and femoral head necrosis. Results: The patients of the three groups were successfully completed. Compared with the hollow screw group and the eccentric shaft screw group, the operation time and intraoperative blood loss of the support plate group significantly increased, the number of fluoroscopy reduced, and the quality of fracture reduction was better, the differences were significant ( P<0.05). The operation time, intraoperative blood loss, and the number of fluoroscopy of the hollow screw group were less than those of the eccentric shaft screw group, the differences were significant ( P<0.05). There was no significant difference in the length of hospital stay between groups ( P>0.05). All patients in the three groups were followed up 21-52 months, with an average follow-up time of 36.0 months, and there was no significant difference between groups ( P>0.05). The incisions of all patients healed by first intention. Imaging reexamination showed that there was no significant difference in the incidence of fracture nonunion between groups ( P>0.05). The fracture healing, partial weight-bearing, and full weight-bearing were significantly earlier in the eccentric shaft screw group and the support plate group than in the hollow screw group ( P<0.05). There was no significant difference in change value of Harris score, the incidence of postoperative deep venous thrombosis and femoral head necrosis between groups ( P>0.05); however, the incidence of internal fixation failure in the support plate group and the eccentric shaft screw group was significantly lower than that in the hollow screw group ( P<0.05). The incidence of postoperative lateral thigh irritation in the support plate group was significantly lower than that in the hollow screw group ( P<0.05); there was no significant difference between the eccentric shaft screw group and the other two groups ( P>0.05). The overall incidences of postoperative complications in the eccentric shaft screw group and the support plate group were significantly lower than that in the hollow screw group ( P<0.05). Conclusion: For young and middle-aged patients with Pauwels type Ⅲ femoral neck fracture, compared with simple hollow screw fixation in an inverted triangular shape, combined with medial support plate or eccentric shaft screw internal fixation can shorten the fracture healing time, reduce the incidences of postoperative complication, more conducive to early functional exercise of the affected limb; at the same time, the operation time and blood loss of combined eccentric shaft screw internal fixation are less than those of combined medial support plate internal fixation, so the hollow screw in an inverted triangular shape combined with eccentric shaft screw fixation may be a better choice.

[Effectiveness of vertical compression of locking plate combined with hollow screws in treatment of Sanders type â ¡ and â ¢ calcaneal fractures].

Objective: To probe into the effectiveness of vertical compression of locking plate combined with hollow screws in the treatment of Sanders type Ⅱ and Ⅲ calcaneal fractures. Methods: The clinical data of 128 patients with Sanders type Ⅱ and Ⅲ calcaneal fractures who were admitted between March 2019 and April 2022 and met the selection criteria were retrospectively analyzed. Among them, 65 patients were treated with locking plate combined with hollow screw vertical compression (study group), and 63 patients were treated with simple locking plate (control group). There was no significant difference in baseline data between the two groups ( P>0.05), such as gender, age, fracture side and Sanders classification, cause of injury, time from injury to operation. The operation time, intraoperative blood loss, hospital stay, and fracture healing time were recorded and compared between the two groups. Before operation and at 12 months after operation, the American Orthopaedic Foot and Ankle Association (AOFAS) score (including total score, pain score, functional score, and alignment score) was used to evaluate the recovery of foot function, and imaging indicators such as calcaneal width, calcaneal height, calcaneal length, Böhler angle, and Gissane angle were measured on X-ray films. Results: All patients were followed up 12 months after operation. There was no significant difference in operation time, intraoperative blood loss, hospital stay, and fracture healing time between the two groups ( P>0.05). Poor wound healing occurred in 1 case in the study group and 2 cases in the control group. At 12 months after operation, there was no significant difference between the two groups in the pre- and post-operative difference of calcaneal length, calcaneal height, Gissane angle, and Böhler angle ( P>0.05). However, the pre- and post-operative difference in calcaneal width in the study group was significantly higher than that in the control group ( P<0.05). The pre- and post-operative difference of AOFAS total score in the study group was significantly higher than that in the control group ( P<0.05), and further analysis showed that the pre- and post-operative difference of pain and function scores in the study group were significantly higher than those in the control group ( P<0.05), while there was no significant difference in the pre- and post-operative difference of force score between the two groups ( P>0.05). Conclusion: Compared with simple locking plate treatment, the treatment of Sanders type Ⅱ and Ⅲ calcaneal fractures with vertical compression of locking plate combined with hollow screws can more effectively improve the width of the subtalar calcaneal articular surface, avoid peroneal longus and brevis impingement, reduce pain, and increase the range of motion of the subtalar joint, and the effectiveness is better.

[Effectiveness comparison of a new hook-shaped anatomical locking plate and conventional anatomical locking plate in treatment of Danis-Weber type A lateral malleolus fractures].

Objective: To investigate the effectiveness of a new hook-shaped anatomical locking plate in the treatment of Danis-Weber type A lateral malleolus fractures. Methods: A retrospective analysis was performed on the clinical data of 45 patients with Danis-Weber type A lateral malleolus fractures who met the selection criteria between November 2020 and November 2022. According to the surgical methods, they were divided into the observation group (treated with the new hook-shaped anatomical locking plate, 23 cases) and the control group (treated with the conventional lateral malleolus anatomical locking plate, 22 cases). There was no significant difference in baseline data such as gender, age, cause of injury, Danis-Weber type of fracture, time from injury to operation, and combined ligament injury between the two groups ( P>0.05). The operation time, partial weight-bearing time, return to work time, and postoperative complications were recorded and compared between the two groups. The function and pain of ankle joint were evaluated by the range of motion of ankle dorsiflexion, plantarflexion, varus, valgus, and visual analogue scale (VAS) score at 1 and 3 months after operation, and at last follow-up, and the American Orthopaedic Foot and Ankle Society (AOFAS) score at 3 months after operation and at last follow-up. Results: All patients were followed up 10-18 months (mean, 15.1 months). There was no significant difference in operation time between the two groups ( P>0.05); the postoperative partial weight-bearing time and return to work time of the observation group were significantly earlier than those of the control group ( P<0.05). During the follow-up, there was 1 case of joint stiffness in the observation group, and 1 case of joint surface displacement, 1 case of joint stiffness, and 1 case of traumatic arthritis in the control group. There was no significant difference in the incidences of complications between the two groups ( P>0.05). With the extension of time after operation, the range of motion of ankle dorsiflexion, plantarflexion, varus, valgus, and VAS score of the two groups gradually improved, and there were significant differences between different time points ( P<0.05); At 1 and 3 months after operation, the above indexes in the observation group were significantly better than those in the control group ( P<0.05), and there was no significant difference between the two groups at last follow-up ( P>0.05). The difference of AOFAS score between the last follow-up and 3 months after operation in the observation group was significantly better than that in the control group ( P<0.05). Conclusion: Compared with the conventional lateral malleolus anatomical locking plate, the new hook-shaped anatomical locking plate has a more reliable fixation effect in the treatment of Danis-Weber type A lateral malleolus fracture, which is conducive to early functional exercise of the ankle joint, so that patients can bear weight earlier and return to work earlier, and the operation time is not significantly prolonged, and the effectiveness is satisfactory.

[Effectiveness of transverse double "8"-shaped tension band technique for Lawrence zone â fracture of the fifth metatarsal base].

Objective: To explore the effectiveness of transverse double "8"-shaped tension band technique in the treatment of Lawrence zoneⅠfracture of the 5th metatarsal base. Methods: Between February 2019 and October 2021, 15 patients with Lawrence zoneⅠfracture of the 5th metatarsal base were treated with transverse double "8"-shaped tension band technique. There were 8 males and 7 females, with a median age of 40 years (range, 23-59 years). The fractures were caused by sprains. The time from injury to operation was 3-7 days (mean, 4.1 days). X-ray films were taken to observe the fracture healing and the anchor looseness and detachment. The foot function was evaluated by American Orthopaedic Foot and Ankle Society (AOFAS) score, visual analogue scale (VAS) score, and the eversion angle of the calcaneal talus joint. Results: The incisions healed by first intention after operation in 14 cases and the incision healed poorly in 1 case. All patients were followed up 8-12 months (median, 10 months). The imaging examination showed that all fractures healed well, with a healing time of 10-14 weeks (mean, 11.7 weeks). At last follow-up, AOFAS score was 82-100 (median, 98); 13 cases were excellent and 2 cases were good, with an excellent and good rate of 100%. VAS score was 0-3 (median, 1). Three cases had mild limited ankle joint range of motion, while 12 cases had normal range of motion. The eversion angle of the calcaneal talus joint was 25°-32° (median, 30°). Conclusion: The application of transverse double "8"-shaped tension band technique for Lawrence zone Ⅰ fracture of the 5th metatarsal base has advantages such as simple operation, avoidance of secondary operation, and reduction of foreign body sensation, with definite effectiveness.

[Effectiveness of injured vertebra fixation with inclined-long pedicle screws combined with interbody fusion for thoracolumbar fracture dislocation with disc injury].

Objective: To investigate the effectiveness of injured vertebra fixation with inclined-long pedicle screws combined with interbody fusion for thoracolumbar fracture dislocation with disc injury. Methods: Between January 2017 and June 2022, 28 patients with thoracolumbar fracture dislocation with disc injury were underwent posterior depression, the injured vertebra fixation with inclined-long pedicle screws, and interbody fusion. There were 22 males and 6 females, with a mean age of 41.4 years (range, 22-58 years). The causes of injury included falling from height in 18 cases, traffic accident in 5 cases, and bruise in 5 cases. Fracture segment included 1 case of T 11, 7 cases of T 12, 9 cases of L 1, and 11 cases of L 2. According to the American Spinal Injury Association (ASIA) scale, the spinal injuries were graded as grade A in 4 cases, grade B in 2 cases, grade C in 11 cases, and grade D in 11 cases. Preoperative spinal canal encroachment ratio was 17.7%-75.3% (mean, 44.0%); the thoracolumbar injury classification and severity score (TLICS) ranged from 9 to 10 (mean, 9.9). Seventeen patients were associated with other injuries. The time from injury to operation ranged from 1 to 4 days (mean, 2.3 days). The perioperative indicators (operation time, intraoperative blood loss, and the occurrence of complications), clinical evaluation indicators [visual analogue scale (VAS) score and Oswestry Disability Index (ODI)], radiologic evaluation indicators [anterior vertebral height ratio (AVHR), kyphosis Cobb angle (KCA), intervertebral space height (ISH), vertebral wedge angle (VWA), displacement angle (DA), and percent fracture dislocation displacement (PFDD)], neurological function, and interbody fusion were recorded. Results: The operation time was 110-159 minutes (mean, 130.2 minutes). The intraoperative blood loss was 200-510 mL (mean, 354.3 mL). All incisions healed by first intention, and no surgical complications such as wound infection or hematoma occurred. All patients were followed up 12-15 months (mean, 12.7 months). The chest and lumbar pain significantly relieved, VAS scores and ODI after operation were significantly lower than those before operation, and further decreased with the extension of postoperative time, with significant differences ( P<0.05). At last follow-up, the ASIA classification of neurological function of the patients was grade A in 3 cases, grade B in 1 case, grade C in 1 case, grade D in 10 cases, and grade E in 13 cases, which was significantly different from preoperative one ( Z=-4.772, P<0.001). Imaging review showed that AVHR, KCA, ISH, VWA, DA, and PFDD significantly improved at 1 week, 3 months and last follow-up ( P<0.05). There was no significant difference between different time points after operation ( P>0.05). At last follow-up, according to the modified Brantigan score, all patients achieved good intervertebral bone fusion, including 22 complete fusion and 6 good intervertebral fusion with a few clear lines. No complications such as internal fixation failure or kyphosis occurred during follow-up. Conclusion: The injured vertebra fixation with inclined-long pedicle screws combined with interbody fusion is an effective treatment for thoracolumbar fracture dislocation with disc injury, which can correct the fracture dislocation, release the nerve compression, restore the injured vertebral height, and reconstruct spinal stabilization.

Pre-sliding technique to improve femoral neck system against the shortening: a retrospective cohort study.

OBJECTIVE: To investigate the efficacy of using pre-sliding technique to prevent postoperative shortening of displaced femoral neck fracture fixed with femoral neck system (FNS). METHODS: Retrospective analysis of 110 cases of displaced femoral neck fracture treated with femoral neck system from September 2019 to November 2022 in our center, which were divided into 56 cases in the pre-sliding group and 54 cases in the traditional group. The baseline data such as gender, age, side, mechanism of injury, fracture type, operation time, intraoperative bleeding were recorded and compared between the two groups, and the quality of fracture reduction, shortening distance, Tip Apex Distance (TAD), union time, Harris score of the hip were also compared between the two groups. RESULTS: The TAD value of the pre-sliding group was smaller than that of the traditional group, and the difference was statistically significant (P < 0.001). The shortening distance in both groups on postoperative day 1 was smaller in the pre-sliding group than in the traditional group, but the difference was not statistically significant (P = 0.07), and the shortening distance was smaller than in the traditional group at 1, 3, 6, and 12 months postoperatively, and the difference was statistically significant (all P < 0.001). Of the 110 cases, 34 (30.9%) had moderate or severe shortening, of which 24 (44.4%) were in the traditional group and 10 (17.9%) in the pre-sliding group, and the difference was statistically significant (P < 0.001), and the Harris score at 1 year, which was higher in the pre-sliding group than in the traditional group, and the difference between the two groups was statistically significant (P < 0.001). There was no statistically significant difference in the comparison of baseline data such as gender, age, side, mechanism of injury, fracture type, operation time, intraoperative bleeding, and quality of reduction between the two groups (all P > 0.05), and no statistically significant difference in fracture healing time between the two groups (P = 0.113). CONCLUSION: The use of the pre-sliding technique of displaced femoral neck fracture fixed with FNS reduces the incidence of moderate and severe shortening, improves the postoperative TAD value, and improves the hip function scores, with a satisfactory midterm efficacy.

Comparative Short-Term Outcomes of Femoral Neck System (FNS) and Cannulated Screw Fixation in Patients with Femoral Neck Fractures: A Multicenter Study.

Background: Femoral neck fractures need to be treated in their early stages with accurate reduction and stable fixation to reduce complications. The authors compared the early radiologic outcomes of femoral neck fractures treated with the recently introduced Femoral Neck System (FNS, Depuy-Synthes) with conventional cannulated screws (CS) in a multicenter design. Furthermore, the factors associated with early failure after FNS were analyzed. Methods: The FNS group included 40 patients treated between June 2019 and January 2020, and the CS group included 65 patients treated between January 2015 and May 2019. The operation was performed in 3 university hospitals. Patient demographics, fracture classification, postoperative reduction quality, sliding distance of FNS or CS, union and time to union, and complication rates were examined. Logistic regression analysis was performed on candidate factors for early failure of the FNS group. Results: The FNS group had a 90% union rate and a mean time to union of 4.4 months, while the CS group had similar results with an 83.1% union rate and a mean time to union of 5.1 months. In the subgroup analysis of Pauwels type III fractures, the union rates were 75.0% and 58.8% in the FNS and CS groups, respectively, and the time to union was significantly shorter in the FNS group with 4.8 months compared to 6.8 months in the CS group. Early failure rate within 6 months of FNS fixation was observed to be 10%, which included 3 reduction failures and 1 excessive sliding with a broken implant. Risk factors for early failure after FNS were identified as displaced fractures (Garden classification type III or IV), poor reduction quality, longer tip-apex distance, greater sliding distance, and 1-hole implants, of which sliding distance was the only significant risk factor in multivariate analysis. Conclusions: In femoral neck fractures, FNS and CS did not show significant differences for short-term radiologic results. FNS resulted in shorter operative time than cannulated screw fixation and favorable outcomes in Pauwels type III femoral neck fractures. The FNS could be considered a reliable and safe alternative to CS when treating femoral neck fractures.

Is Surgical Treatment Necessary for the Treatment of a Jones Fracture?: A Retrospective Study.

Background: Jones fractures are common injuries that can be treated conservatively or surgically. However, the optimal treatment approach remains controversial. This study aimed to compare the clinical outcomes of conservative and operative treatments for Jones fractures and determine whether surgical treatment is necessary. Methods: A retrospective study was conducted on 69 patients with Jones fractures treated at our hospital. The patients were divided into 2 groups: conservative (C group; n = 46) and operative (O group; n = 23) treatments. Patients were followed up after 2, 6, and 12 weeks, and every 3 months thereafter. However, outpatient follow-ups were conducted between 8 and 10 weeks as needed. The mean follow-up period was 14.5 weeks (range, 12-24 weeks). In group C, the patients were treated with a non-weight-bearing cast for 4-6 weeks, followed by additional weight-bearing boot immobilization before returning to exercise. In group O, patients were treated surgically using a bicortical screw or intramedullary internal fixation. Time to radiologic union, clinical union, return to sports, visual analog scale (VAS), Foot Function Index-Revised Short Form (FFI-RS), and American Orthopedic Foot and Ankle Society (AOFAS) scores were evaluated. Results: Sixty-nine patients were included in the analysis. There were statistically significant differences in the time to radiologic union and return to sports, VAS score in the second week, and FFI-RS score in the 12th week. In group C, favorable outcomes were observed in terms of the time to return to sports, VAS score in the second week, and FFI-RS score in the 12th week. Contrastingly, in group O, better results were observed in time to radiologic union. The AOFAS score was excellent at the final follow-up, with no significant differences between groups. Complication rates were 10.8% and 13% in groups C and O, respectively. Conclusions: Surgical treatment is sometimes necessary for Jones fractures, but conservative treatment should also be considered because of the favorable outcomes. Conservative treatment can be a good option for patients who are risk-averse and place a high value on fracture healing without surgery.

Fragment excision and triceps V-Y advanced reattachment using suture anchor for olecranon nonunion: A case report.

RATIONALE: The nonunion of olecranon fractures is uncommon in simple fractures, and it is challenging to treat surgically due to the disruption of the anatomy of the elbow joint. There is limited literature on surgical options, and several factors to determine the treatment, including the amount and quality of bone stock, age, and degree of articular damage. PATIENT CONCERNS: A 58-year-old man presented at the clinic with neglected olecranon fracture for 1 year (case 1). A 74-year-old man (case 2) presented with consistent pain and limited of motion after surgery for olecranon fracture. DIAGNOSIS: Both patients were diagnosed with olecranon nonunion. INTERVENTION: Both patients received the excision of nonunited fragment and reattaching with V-Y advancement of triceps. OUTCOMES: Range of motion and Mayo elbow performance score were improved after surgery. LESSONS: This technique is useful in patients who cannot undergo other surgical options due to insufficient bone quality and elbow function, and it can lead to satisfactory outcomes with an acceptable range of motion and pain relief.

[Meta-analysis of autologous bone grafts and bone substitute for the treatment of tibial plateau fractures].

OBJECTIVE: To explore clinical efficacy of autologous bone grafts and bone substitute for the treatment of tibial plateau fractures by Meta analysis. METHODS: Controlled clinical studies on autogenous bone transplantation and bone substitutes in treating tibial plateau fractures published on PubMed,Web of Science,CNKI,Wanfang and other databases from January 2005 to August 2022 were searched by computer. Literature screening and data extraction were performed according to randomized controlled trial(RCT),and the quality of RCT were evaluated by using intervention meta-analysis criteria in Cochrane manual. Meta-analysis of joint depression,secondary collapse rate of articular surface,blood loss,operative time and infection rate between two methods were performed by Rev Man 5.3 software. RESULTS: Seven RCT studies (424 patients) were included,296 patients in bone replacement group and 128 patients in autograft group. Operative time [MD=-16.79,95%CI(-25.72,-7.85),P=0.000 2] and blood loss[MD=-70.49,95%CI(-79.34,-61.65),P<0.000 01] between two groups had statistically differences,while joint depression[MD=-0.17,95%CI(-0.91,0.58),P=0.66],secondary collapse rate of joint surface[RR=-0.74, 95%CI(0.35,1.57),P=0.43],infection rate [RR=1.21,95%CI(0.31,4.70),P=0.78] between two groups had no differences. CONCLUSION: The effects of bone substitute and autograft for the treatment of tibial plateau fracture have similar effects in terms of joint depression,secondary articular surface collapse rate and infection rate. However,compared with autologous bone transplantation,bone replacement could reduce blood loss and shorten operation time.

[Digital study on proximal clavicle anatomical plate based on 3D printing technology].

OBJECTIVE: To explore feasibility of 3D metal printing technology combined with virtual design proximal clavicle anatomical plate. METHODS: A 52-year-old male healthy volunteer was retrospectively selected to design proximal clavicle anatomical plate system by using Mimics15.01,NX12.0 and other software. STL data were input into 3D printer to print 1:1 clavicle model and proximal clavicle anatomical plate. The fit of the plate was tested in vitro and the accuracy of screw position was evaluated by imaging. Printing time of model,nail path design and fabrication time of the anatomical plate at proximal clavicle were recorded. RESULTS: The 3D metal printing proximal clavicle anatomical plate fitted well to clavicle model,orientation of proximal clavicle locking screw was accurate,and X-ray and CT scan showed the screw position was good. Printing time of model,the time of nail path design,and the time of making anatomical plate of proximal clavicle were 120,15 and 300 min respectively. CONCLUSION: The proximal clavicular anatomical plate system based on 3D metal printing technology could achieve good lamination of proximal clavicular fracture plate and precise screw placement,providing a new and accurate surgical method for the treatment of the proximal clavicular fracture.

[Clinical effect of allogeneic peroneal bone marrow support combined with plate fixation for the treatment of Neer type â £ proximal humeral fractures].

OBJECTIVE: To explore clinical effect of allogeneic peroneal bone marrow support combined with plate internal fixation in treating Neer type Ⅳproximal humeral fractures. METHODS: From December 2017 to December 2020,12 patients with Neer type Ⅳ proximal humeral fractures were treated with allogeneic peroneal bone marrow support combined with plate internal fixation,including 7 males and 5 females,aged from 56 to 78 years old;the time from injury to operation ranged from 1 to7 days. Operative time,fracture healing time and complications during follow-up were observed,and clinical efficacy was evaluated by Constant-Murley score at the latest follow-up. RESULTS: All patients were obtained follow up for 20 to 29 months. All patients got bone healing and incisicons were healed at stageⅠ,operative time ranged from 95 to 138 min,blood loss ranged from 210 to 275 ml,fracture healing time ranged from 14 to 18 weeks. Two patients occurred postoperative shoulder stiffness and recovered after 2 weeks of passive exercise. There were no complications such as infection,poor wound healing,and failure (fracture and loosening) of internal fixators occurred. Constant-Murley shoulder function score ranged from 69 to 89 at the latest follow up,2 patients got excellent results,9 good and 1 fair. CONCLUSION: The application of allogeneic fibular bone marrow placement could provide effective support for medial humerus,which is conducive to assisting reduction of fracture end,reducing occurrence of internal fixation failure caused by collapse of humerus head and screw perforation,and significantly improving function of shoulder joint.

[Progress on treatment of acetabular quadrilateral plate injury].

Acetabular quadrilateral plate injury has become a hot spot and focus in the field of orthopaedic trauma and pelvic floor function in recent years. Although there are five fracture types,they are all based on fracture morphology,without considering the pulling force of ligaments,joint capsular and muscles. A perfect classification needs to describe the displacement of bone mass in three-dimensional space to better guide reduction and fixation. The seven incision and exposure methods are still the traditional open-eye surgery,and how to protect the criss-crossing vascular neural network and pelvic organs is still the focus. Quadrilateral defect causes dislocation of artificial hip joint,and quantitative evaluation of quadrilateral defect volume and revision techniques are still a hot topic. In this paper,the viewpoints of three-dimensional network structure of acetabular pelvic vascular anatomy,anatomical surgical target channel and fixation anchor point of acetabular fracture reduction are proposed to design new techniques for accurate and minimally invasive surgical operations,in order to realize the requirements of rapid orthopedic rehabilitation.

[Comparison of the efficacy of TiRobot orthopaedic robot assisted F screw technique and inverted triangle parallel nail internal fixation in the treatment of unstable femoral neck fractures].

OBJECTIVE: To compare the effectiveness of TiRobot assisted F screw technique and inverted triangle parallel nail internal fixation in the treatment of unstable femoral neck fractures. METHODS: A retrospective analysis was conducted on 72 patients with unstable femoral neck fractures who were treated with percutaneous cannulated screw fixation assisted with TiRobot Orthopaedic robot from December 2019 to April 2021. Among them, 37 patients were treated with F screw internal fixation, including 16 males and 21 females, aged 47 to 64 years old with an average of （53.87±5.28） years old；According to Pauwels classification, there were 1 case of type Ⅰ, 19 cases of type Ⅱ, 17 cases of type Ⅲ；8 cases of combined medical diseases；17 cases of falling, 8 cases of traffic accident and 12 cases of falling from height；The time from injury to operation was 29 to 49 hours with average of （35.00±7.34） hours. Another 35 cases used internal fixation with an inverted triangle parallel nail, including 13 males and 22 females with an average age of 46 to 63 years old （52.36±5.05） years old；According to the Pauwels injury classification：there were 2 cases of type Ⅰ, 21 cases of type Ⅱ, 12 cases of type Ⅲ；6 cases of medical diseases, 15 cases of falling injury, 9 cases of traffic accident, 11 cases of falling injury；The time from injury to operation was 30 to 45 hours with an average of （33.00±6.83） h. The intraoperative blood loss, operation time, intraoperative fluoroscopy times, follow-up time, fracture healing time, postoperative complications were observed and compared between the two groups. The hip joint function was evaluated by Harris score at 6 months and 12 months after operation. RESULTS: There was no significant difference in operation time, intraoperative blood loss, intraoperative fluoroscopy times and other intraoperative data between two groups（P>0.05）. Both groups were followed up regularly, and the follow-up time was 12 to 16 months. The fracture healing time and Harris score of the F screw internal fixation group were better than those of the inverted triangle parallel nail internal fixation group （P<0.05）. There was 1 case of femoral neck shortening in the F screw internal fixation group, 1 case of nonunion, 1 case of nail withdrawal, and 1 case of lower extremity deep vein thrombosis in the inverted triangle internal fixation group. The incidence of complications in the F screw internal fixation group was lower than that in the inverted triangle parallel nail internal fixation group（P<0.05）. CONCLUSION: Percutaneous cannulated F screw technique using Tirobot navigation positioning system is a safe and effective treatment for patients with unstable femoral neck fractures. It can significantly shorten the fracture healing time, reduce the incidence of postoperative complications, significantly improve hip joint function, and improve the quality of life.

[Virtual preoperative planning and 3D-printed templates for pre-contoured plates in treatment of acetabular posterior wall fractures].

OBJECTIVE: To evaluate the feasibility and accuracy of virtual preoperative planning and 3D-printed templates for pre-contoured plates for the treatment of posterior wall fractures of the acetabulum. METHODS: A retrospective analysis of 29 patients with posterior acetabular wall fractures treated between August 2017 and March 2021 were divided into 2 groups based on whether to use preoperative virtual planning and 3D printed template. In 3D-printing group, there were 14 patients, including 10 males and 4 females； aged from 21 to 53 years old；CT-based virtual surgical planning was done using Mimics and 3-Matic software and 3D-printed templates for pre-contoured plates were adopted. In conventional group, there were 15 patients, including 10 males and 5 females；aged from 19 to 55 years old；conventional method of intra-operative contouring to adapt the plate to the fracture region was adopted. Blood loss, surgical time, radiographic quality of reduction, and hip function were compared between groups. RESULTS: The difference in operation time and intraoperative blood loss was significant（P<0.05）. Twenty-three patients were followed up from 12 to 30 months, and the fractures in both groups healed with a healing time of 3 to 6 months. At the last follow-up, the Merle d'Aubign-Postel score of the 3D printed group was lower than that of the conventional group（P<0.05）, with no significant differences in walking ability, hip mobility and total score（P>0.05）. In 3D printing group, 6 cases were excellent, 5 cases were good, 3 cases were fair；in conventional group, 5 cases were excellent, 5 cases were good, 4 cases were fair, 1 case was worse；no significant difference between two groups（P>0.05）. CONCLUSION: Virtual preoperative planning and 3D-printed templates for pre-contoured plates can reduce operative time and the blood loss of surgery, improve the quality of reduction. This method is efficient, accurate and reliable to treat acetabular posterior wall fractures.

[Analysis of the risk factors for delayed union of extra-articular fractures of the middle and lower third of the tibia treated by locking plate].

OBJECTIVE: To investigate the risk factors for delayed union of extra-articular fractures of the middle and lower third of the tibia treated by locking plate. METHODS: Total of 135 patients of extra-articular fractures of the middle and lower third of the tibia from January 2013 to December 2018 were retrospectively analyzed, including 85 males and 50 females, ranged from 19 to 80 years old. All cases were treated with locking plates. The patients were divided into union group and delayed union group according to the condition of fracture union. The risk factors of delayed healing were determined by univariate analysis of 14 factors that might affect fracture healing first, then the factors with significance were analyzed by binary Logistic regression. RESULTS: There were 13 patients of delayed union, and the rate of delayed union was 9.63%. Univariate analysis showed that delayed union was associated with age, smoking, reduction method, anemia and time of preoperative preparation. Regression analysis showed that age[OR=0.849, 95%CI（0.755, 0.954）, P=0.006], smoking[OR=0.020, 95%CI（0.002, 0.193）, P=0.001], reduction method[OR=23.924, 95%CI（2.210, 258.943）, P=0.009], anemia[OR=0.016, 95%CI（0.001, 0.289）, P=0.005] were the contributory factors for delayed union. CONCLUSION: Young age, smoking, closed reduction and anemia are the risk factors for delayed union of extra-articular fractures of the middle and lower third of the tibia treated by locking plate.