Nanoengineered 3D-printing scaffolds prepared by metal-coordination self-assembly for hyperthermia-catalytic osteosarcoma therapy and bone regeneration.

The integration of functional nanomaterials with tissue engineering scaffolds has emerged as a promising solution for simultaneously treating malignant bone tumors and repairing resected bone defects. However, achieving a uniform bioactive interface on 3D-printing polymer scaffolds with minimized microstructural heterogeneity remains a challenge. In this study, we report a facile metal-coordination self-assembly strategy for the surface engineering of 3D-printed polycaprolactone (PCL) scaffolds with nanostructured two-dimensional conjugated metal-organic frameworks (cMOFs) consisting of Cu ions and 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP). A tunable thickness of Cu-HHTP cMOF on PCL scaffolds was achieved via the alternative deposition of metal ions and HHTP. The resulting composite PCL@Cu-HHTP scaffolds not only demonstrated potent photothermal conversion capability for efficient OS ablation but also promoted the bone repair process by virtue of their cell-friendly hydrophilic interfaces. Therefore, the cMOF-engineered dual-functional 3D-printing scaffolds show promising potential for treating bone tumors by offering sequential anti-tumor effects and bone regeneration capabilities. This work also presents a new avenue for the interface engineering of bioactive scaffolds to meet multifaceted demands in osteosarcoma-related bone defects.

Functional anti-bone tumor biomaterial scaffold: construction and application.

Bone tumors, including primary bone tumors and bone metastases, have been plagued by poor prognosis for decades. Although most tumor tissue is removed, clinicians are still confronted with the dilemma of eliminating residual cancer cells and regenerating defective bone tissue after surgery. Therefore, functional biomaterial scaffolds are considered to be the ideal candidates to bridge defective tissues and restrain cancer recurrence. Through functionalized structural modifications or coupled therapeutic agents, they provide sufficient mechanical strength and osteoinductive effects while eliminating cancer cells. Numerous novel approaches such as photodynamic, photothermal, drug-conjugated, and immune adjuvant-assisted therapies have exhibited remarkable efficacy against tumors while exhibiting low immunogenicity. This review summarizes the progress of research on biomaterial scaffolds based on different functionalization strategies in bone tumors. We also discuss the feasibility and advantages of the combined application of multiple functionalization strategies. Finally, potential obstacles to the clinical translation of anti-tumor bone bioscaffolds are highlighted. This review will provide valuable references for future advanced biomaterial scaffold design and clinical bone tumor therapy.

Endothelial Stat3 activation promotes osteoarthritis development.

The mechanism of the balance between subchondral angiogenesis and articular damage within osteoarthritis (OA) progression remains a mystery. However, the lack of specific drugs leads to limited clinical treatment options for OA, frequently failing to prevent eventual joint destruction in patients. Increasing evidence suggests that subchondral bone angiogenesis precedes cartilage injury, while proliferating endothelial cells (ECs) induce abnormal bone formation. Signal transducer and activator of transcription 3 (Stat3) is triggered by multiple cytokines in the OA microenvironment. Here, we observed elevated Stat3 activation in subchondral bone H-type vessels. Endothelial Stat3 activation will lead to stronger cell proliferation, migration and angiogenesis by simulating ECs in OA. In contrast, either Stat3 activation inhibition or knockdown of Stat3 expression could relieve such alterations. More interestingly, blocking Stat3 in ECs alleviated angiogenesis-mediated osteogenic differentiation and chondrocyte lesions. Stat3 inhibitor reversed surgically induced subchondral bone H-type vessel hyperplasia in vivo, significantly downregulating vessel volume and vessel number. Due to the reduced angiogenesis, subchondral bone deterioration and cartilage loss were alleviated. Overall, our data suggest that endothelial Stat3 activation is an essential trigger for OA development. Therefore, targeted Stat3 blockade is a novel promising therapeutic regimen for OA.

Ultrasound-triggered in situ gelation with ROS-controlled drug release for cartilage repair.

Cartilage defects are usually caused by acute trauma and chronic degeneration. However, it is still a great challenge to improve the repair of articular cartilage defects due to the limited self-regeneration capacity of such defects. Herein, a novel ROS-responsive in situ nanocomposite hydrogel loaded with kartogenin (KGN) and bone marrow-derived stem cells (BMSCs) was designed and constructed via the enzymatic reaction of fibrinogen and thrombin. Meanwhile, a ROS-responsive thioketal (TK)-based liposome was synthesized to load the chondrogenesis-inducing factor KGN, the bioenzyme thrombin and an ultrasound-sensitive agent PpIX. Under ultrasound stimulation, the TK-based liposome was destroyed, followed by in situ gelation of fibrinogen and thrombin. Moreover, sustained release of KGN was realized by regulating the ultrasound conditions. Importantly, ROS generation and KGN release within the microenvironment of the in situ fibrin hydrogel significantly promoted chondrogenic differentiation of BMSCs via the Smad5/mTOR signalling pathway and effectively improved cartilage regeneration in a rat articular cartilage defect model. Overall, the novel in situ nanocomposite hydrogel with ROS-controlled drug release has great potential for efficient cartilage repair.

[Short-term effectiveness of TiRobot combined with O-arm navigation system in minimally invasive treatment of hindfoot fracture].

Objective: To investigate the short-term effectiveness of TiRobot combined with O-arm navigation system in the minimally invasive treatment of hindfoot fracture. Methods: Between March 2019 and March 2021, 25 patients with hindfoot fractures were admitted. There were 14 males and 11 females, with an average age of 51.7 years (range, 19-76 years). The causes of injuries included falling from height in 17 cases and traffic accident in 8 cases. The interval between injury and operation was 1-3 days (mean, 2.1 days). There were 16 cases of calcaneus fracture, 7 cases of talus fracture, and 2 cases of calcaneus and talus fractures. According to Sanders classification criteria, the calcaneus fractures were classified as type Ⅱ in 10 cases and type Ⅲ in 8 cases; according to the Hawkins classification criteria, the talus fractures were classified as type Ⅱ in 4 cases and type Ⅲ in 5 cases. Preoperative American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score was 48.1±9.1. During operation, the fractures were fixed with the percutaneous cannulated screws with the assistance of the TiRobot combined with the O-arm navigation system. The operation time, hospital stay, and the occurrence of related complications were recorded. X-ray films were reviewed to evaluate the fracture healing and the occurrence of talus osteonecrosis, and the width, length, height, Böhler's angle, and Gissane's angle of the calcaneus were measured; AOFAS ankle-hindfoot score was used to evaluated the foot function. Results: The operation time ranged from 47 to 71 minutes (mean, 60.5 minutes). The length of hospital stay ranged from 2 to 5 days (mean, 3.4 days). All incisions healed by first intention. All patients were followed up 12-24 months (mean, 17.3 months). One patient demonstrated hypoesthesia on the lateral side of foot after operation and recovered after symptomatic treatment. All fractures healed confirmed by X-ray films and the healing time ranged from 10 to 16 weeks (mean, 11.8 weeks). No talus osteonecrosis occurred during follow-up. There were significant differences in the width, length, height, Böhler's angle, and Gissane's angle of the calcaneus between pre-operation and at last follow -up ( P<0.05). At last follow-up, AOFAS ankle-hindfoot score was 91.2±5.0, the difference was significant when compared with preoperative score ( t=22.169, P<0.001). The results were excellent in 16 cases and good in 9 cases, with an excellent and good rate of 100%. Conclusion: TiRobot combined with O-arm navigation system for minimally invasive treatment of hindfoot fractures can obtain the satisfactory short-term effectiveness, with the advantages of less surgical trauma, precise fixation, and fewer complications.

A new decompression technique for upper lumbar fracture with neurologic deficit-comparison with traditional open posterior surgery.

BACKGROUND: Surgery is usually recommended for thoracolumbar fracture with neurologic deficit. However, traditional open posterior approach requires massive paraspinal muscles stripping, and the canal decompression may be limited and incomplete. We aimed to investigate a new approach via the Wiltse approach and the Kambin's Triangle. METHODS: Twenty-one consecutive patients with traumatic upper lumbar fracture who received this new approach surgery between January 2015 and January 2016 constituted the new approach group. Twenty-nine patients received the traditional open posterior surgery between January 2014 and January 2015 were classified as the traditional posterior surgery group. Surgical informations including operative time, blood loss, drainage volume, hospitalization days were collected and compared among the two groups. The American Spinal Injury Association (ASIA) impairment scale and Visual Analog Score (VAS) were evaluated preoperatively, postoperatively and at 12 months follow-up. RESULTS: Patients in the new approach group had fewer operation time (128.3 ± 25.1 vs 151 ± 32.2 min, P = 0.01), less blood loss (243.8 ± 135.5 vs 437.8 ± 224.9 ml, P = 0.001) and drainage volume (70.7 ± 57.2 vs 271.7 ± 95.5 ml, P < 0.001), as well as shorter hospitalization stay than the traditional posterior surgery group (6.6 ± 1.8 vs 8.5 ± 2.4 d, P = 0.004). Similar neurologic recovery according to ASIA grade was achieved in both groups (Recovery index: 0.90 ± 0.53 vs 0.86 ± 0.51, P = 0.778). While the pain level was significantly lower in the new approach group postoperatively (2.6 ± 0.7 vs 3.5 ± 0.9, P < 0.001) and at 12 months follow-up (1.4 ± 0.9 vs 2.4 ± 0.8, P < 0.001). CONCLUSION: The present new approach was successfully applied in the treatment of upper lumbar fracture with neurologic deficit. It can reduce iatrogenic trauma and achieve similar or better outcomes compared to the traditional posterior surgery.

Modified technique for C1-2 screw-rod fixation and fusion using autogenous bicortical iliac crest graft.

INTRODUCTION: Various techniques have been described for posterior atlantoaxial fusion. Sublaminar passage of the wire/cable is cumbersome with a risk of spinal cord injury. Packing morselized bone grafts into the C1-2 facet joints may be difficult and it may cause massive bleeding and neuropathic pain or posterior scalp numbness postoperatively. We introduce a modified method by using C1-2 screw-rod fixation (SRF) to compress a structural iliac bone graft between the posterior elements of C1 and C2 without supplemental wiring construct. MATERIALS AND METHODS: From December 2006 to May 2009, 35 consecutive patients with atlantoaxial instability treated by this method were reviewed retrospectively. Clinical and radiographic history was recorded. Patients with neck pain had relieved significantly after surgery and the neurologic status was also improved greatly. Thirty-three (94.3%) patients gained bony fusion at 3 months postoperatively. No vertebral artery and spinal cord injuries were noted. There was no instrumentation failure during the observation period. CONCLUSION: We conclude that the C1-2 SRF with construct-compression structural bone grafting can be used for C1-2 fusion with relatively simple performance and less time-consuming in selected cases.

C2 laminar screw and C1-2 transarticular screw combined with C1 laminar hooks for atlantoaxial instability with unilateral vertebral artery injury.

Transarticular screw fixation (TASF) is technically demanding, with high risk of vertebral artery (VA) injury. How to manage intraoperative VA injury and choose optimal alternative fixation becomes a concern of spinal surgeons. In this study, the management strategy for a patient with suspected intraoperative VA injury was analyzed. A 53-year-old woman developed type II odontoid fracture and brain stem injury due to a motor vehicle accident 3 months earlier. After conservative treatments, the brain stem injury improved, but with residual ocular motility defect in the right eye. The odontoid fracture did not achieve fusion with displacement and absorption of fracture fragments. After admission, atlantoaxial fixation using bilateral C1-2 transarticular screws (TASs) combined with C1 laminar hooks was planed. The first TAS was inserted successfully. Unfortunately, suspected VA injury developed during tapping the tract for the second TAS. Considering the previous brain stem injury and that directly inserting the screw to tamponade the hemorrhage might cause VA stenosis or occlusion, we blocked the screw trajectory with bone wax. C2 laminar screw was implanted instead of intended TAS on the injured side. The management strategy for suspected VA injury should depend on intraoperative circumstances and be tailored to patients. Blocking screw trajectory with bone wax is a useful method to stop bleeding. Atlantoaxial fixation using C2 laminar screw and C1-2 TAS combined with C1 laminar hooks is an ideal alternative procedure.

Relation between alignments of upper and subaxial cervical spine: a radiological study.

OBJECTIVE: To reveal the relation between alignments of upper and subaxial cervical spine and deduce the optimal atlantoaxial fusion angle by a radiological study. METHODS: 414 asymptomatic volunteers (213 males, 201 females) underwent cervical lateral radiographs in neutral position. The Oc-C2 angle, C1-C2 angle and C2-C7 angle were measured. Relations among these three angles and relations between angles and age were analyzed. RESULTS: The mean Oc-C2 angle was 16.3° ± 7.0° in females, significantly larger than 14.9° ± 6.5° in males. The mean C1-C2 angles were 28.2° ± 4.0° in females and 26.4° ± 4.6° in males, and C2-C7 angles were 12.7° ± 6.6° and 16.3° ± 7.3°, correspondingly. The mean C1-C2 angle in females was significantly larger than that in males, while C2-C7 angle smaller than that in males. The C2-C7 angle correlated significantly not only with C1-C2 angle but also with Oc-C2 angle. And correlation between C1-C2 angle and C2-C7 angle was stronger than that between Oc-C2 angle and C2-C7 angle. There were also significant positive correlations between C1-C2 and Oc-C2 angles. Oc-C2 angle, C1-C2 angle, and C2-C7 angle correlated significantly with age in both sexes. CONCLUSIONS: There were negative correlations between C1-C2 angle and C2-C7 angle as well as between Oc-C2 angle and C2-C7 angle, and the former correlation was stronger. C1-C2 fixation angle was the key to regulate postoperative subaxial alignment in atlantoaxial arthrodesis. The optimal atlantoaxial fusion angle may be between 25° and 30°.

Anterior hybrid decompression and segmental fixation for adjacent three-level cervical spondylosis.

OBJECTIVE: To evaluate the outcomes of anterior hybrid decompression and segmental fixation for adjacent three-level cervical spondylosis. METHODS: 53 patients with adjacent three-level cervical spondylosis underwent anterior hybrid decompression and segmental fixation. Titanium mesh and PEEK cage were used to span the defects due to decompression and anterior locking plate was placed over the entire construct. Japanese Orthopedic Association (JOA) scores, segmental and C2-C7 angles before and after operation were analyzed. RESULTS: The average follow up was 37.3 ± 7.0 months. Bone fusions were observed in all patients at follow-up intervals. JOA scores improved from preoperative 8.1 ± 2.2 (range 4-13) to 13.1 ± 2.3 (range 7-16) at final follow-up (P = 0.000). Meanwhile, surgical segmental angle was significantly improved from preoperative 6.9 ± 8.3° (range -10.4° to 27.6°) to postoperative 16.3 ± 7.2° (range -2.0° to 37.6°)(P = 0.000), and C2-C7 angle from 9.7 ± 8.6° (range -9.9° to 27.4°) to 17.8 ± 7.7° (range -1.2° to 34.3°) (P = 0.000). Postoperative complications included C5 palsy, cerebrospinal fluid leakage, hematoma, and titanium mesh subsidence. CONCLUSION: Anterior hybrid decompression and segmental fixation is a safe and effective procedure for adjacent three-level cervical spondylosis.

Desmoplastic fibroma of the cervical spine: case report and review of the literature.

STUDY DESIGN: A case report and literature review are presented. OBJECTIVE: To present a rare case of desmoplastic fibroma (DF) in the cervical spine and discuss the diagnosis and treatment of this disorder. SUMMARY OF BACKGROUND DATA: DF is an extremely rare primary tumor of bone, especially in cervical spine. It is a benign but locally aggressive tumor of the connective tissue. It has a predilection for the mandible and the metadiaphyses of long bones. It has a propensity for local recurrence, especially after intralesional resection. METHODS: We report on a 70-year-old woman with a DF of the fourth and fifth cervical vertebrae. The patient complained of progressive neck pain and limitation of activity. After radiologic evaluation, a mass lesion was found on the fourth and fifth cervical vertebral bodies. A 2-level corpectomy with wide marginal resection of the tumor was performed through the anterior approach, and the histopathologic examination yielded the diagnosis of DF. Reconstruction was achieved with a long titanium mesh and locking plate with autologous iliac crest bone graft. RESULTS: After surgery, pain was completely relieved, and neurologic function was normal. The postoperative course was uneventful, and the patient has been well without recurrence for 35 months of follow-up evaluation. CONCLUSION: Patients with DF of the cervical spine may present with the arm and neck pain mimicking cervical disc disease. High index of suspicion by the clinicians must be practiced to make the appropriate diagnosis, and histologic confirmation of the diagnosis is essential. Surgical resection with wide margins is the preferred treatment.

C2 translaminar screw as the optimal choice for atlantoaxial dislocation with C2-C3 congenital fusion.

OBJECTIVE AND IMPORTANCE: The entry point and trajectory are very important for transarticular screw (TAS) and C2 pedicle screw (PDS) plantation. When the physical size is not large enough for the screw passing through, an accurate entry point is the most important point for successful screw insertion without vertebral artery (VA) injury and spinal cord injury. Once the laminas of C2 and C3 are fused, the normal anatomic mark might disappear and the insertion point would be hard to find. As a result, the complication of TAS or PDS implantation increases rapidly. We used C2 translaminar screws (TLSs) with C1 lateral mass screws as the optimal fixation for atlantoaxial dislocation in order to reduce the risk of VA injury and spinal cord injury. CLINICAL PRESENTATION: A 37-year-old woman with atlantoaxial dislocation due to obsolete odontoid fracture complained of neck pain and myelopathy. Preoperative CT reconstruction showed C2-C3 fusion and small size of C2 isthmus. TECHNIQUE: The patient underwent posterior atlantoaxial fusion using C1 lateral mass screws and C2 TLSs. The posterior arch of atlas was removed for decompression and fusion was done at C1-C2 joints by grafting bone fragments from the posterior iliac crest. CONCLUSION: TLSs combined with C1 lateral mass screws might be a useful technique for patients with atlantoaxial dislocation and C2-C3 fusion, especially with small size of C2 isthmus. Also, the fusion of posterior elements between C2 and C3 might be a relative contraindication for TAS fixation.

NgR expression in macrophages promotes nerve regeneration after spinal cord injury in rats.

OBJECTIVE: This study aimed to investigate the expression of Nogo-66 receptor (NgR) in macrophages after SCI and clarify its role in neuron regeneration. METHODS: Macrophages harvested from injured spine cord of rats were stained by double immunofluorescence labeling technique to observe the expression of NgR at histological and cellular levels. Macrophages which expressed NgR were constructed in vitro, and then the effects of NgR on macrophage phagocytosis and neuraxon regeneration in three groups (NgR-macrophages group, mock group and normal macrophages group) were studied using Western blot, micro-MTT colorimetry, and LDH assay separately. RESULTS: The results showed that CD68-positive macrophages in injured tissue of spine cord expressed NgR after double immunofluorescence staining on day 7 after SCI, and so did macrophages isolated and cultured from the injured spine cord. The results of Western blot showed that phagocytosis of macrophages in NgR-macrophages group was much better than that in mock group and normal macrophage group (p < 0.05). And the results of Micro-MTT colorimetry and LDH assay indicated that the capacity of neuraxon regeneration in NgR-macrophages group was significantly higher than that in the other two groups (p < 0.05). CONCLUSIONS: The results suggested that there was NgR expressing in the infiltrated macrophages following SCI, which increased phagocytosis of the macrophages, and promoted post-SCI CNS regeneration in vitro.

Biomechanical assessment of bilateral C1 laminar hook and C1-2 transarticular screws and bone graft for atlantoaxial instability.

UNLABELLED: STUDYDESIGN: In vitro biomechanical test was conducted to compare the stability of 5 different atlantoaxial posterior fusion techniques. OBJECTIVE: To evaluate the biomechanical stability of an atlas laminar hook combined with transarticular (TA) screws relative to 4 different conventional fusion techniques. SUMMARY OF BACKGROUND DATA: The atlantoaxial instability caused by fractures, rheumatoid arthritis, congenital deformity, or traumatic lesions of the transverse ligament often result in acute or chronic spinal cord compression, a possible threat to a patient's life. Posterior atlantoaxial fixations are used to reconstruct the stability of atlantoaxial articulation. Conventional posterior atlantoaxial fixations are associated with high rates of pseudoarthrosis and carry the potential risk of neurologic complication. TA screw fixation can provide an excellent biomechanical stability. As a modified 3-point fixation technique, the bilateral C1-2 TA screws have been combined with C1 laminar hook and bone grafts. This modified technique had carried good clinical outcomes. METHODS: Eight human specimens (C0-C4) were loaded nondestructively with pure moments and the range of motion at the level of C1-C2 was measured. Eight specimens were implanted with each of the following techniques, respectively: Gallie fixation, C1-2 TA screw fixation combined with Gallie fixation, C1-2 TA screw fixation, C1 laminar hook combined with C1-2 TA screw fixation plus bone grafts, and the C1 lateral mass screws in the atlas combined with C2 isthmic screws in axis. RESULTS: Although the C1-2 TA screws best restricted lateral bending and axial rotation, the modified 3-point fixation technique additionally restricted flexion-extension and provided the excellent stability. Differences in axial rotation and lateral bending (with + or - 1.5 Nm load) were observed when the 3-point fixation techniques (TA + Gallie and TA + hook) were compared with atlas lateral mass screws in the atlas combined with isthmic screws in axis. CONCLUSIONS: The modified C1 laminar hook combined with C1-2 TA screws and bone graft fixation provided the best biomechanical stability. The C1 lateral mass screws in the atlas combined with isthmic screws in axis fixation is a sound alternative when the C1-2 TA screw fixation is not feasible.

Bilateral atlas laminar hook combined with transarticular screw fixation for an unstable bursting atlantal fracture.

INTRODUCTION: The unstable atlas burst fracture ("Jefferson fracture") is a fracture of the anterior and posterior atlantal arch with rupture of the transverse atlantal ligament and an incongruence of the atlanto-occipital and the atlanto-axial joint facets. The posterior atlantoaxial fusion is frequently used to reconstruct the stability of atlantoaxial joint. Conventional posterior atlantoaxial fixations are associated with high rates of pseudoarthrosis and chronic atlantoaxial instability. As a modified three-point fixation the bilateral C1-2 transarticular screws combined with C1 laminar hook and bone grafts can provide best biomechanical stability, but no standard protocol has been reported for the use of this fusion technique. A retrospective review of clinical series should be conducted to evaluate the clinical outcome of bilateral atlas laminar hook combined with transarticular screw fixation for unstable bursting atlantal fracture. MATERIALS AND METHODS: From March 2002 to March 2006, there were total 12 cases of unstable atlantal bursting fractures, 10 males and 2 females, age ranging 18-54, with mean of 36 years old. All patients were operated on posterior atlantoaxial fusion using bilateral atlas laminar hook combined with transarticular screw fixation after atlantoaxial joint were reduced and followed up for 12-24 months. The medical records and radiographs of the 12 patients were reviewed. Each patient underwent a complete cervical radiograph series including lateral flexion-extension view and a computed topographic scan. The Frankel grades and ASIA scores were applied to assess the neurologic status. RESULTS: In all patients, a good bony fusion of the atlanto-axial segment was achieved. All patients showed significant improvement of the neurologic defect and no instability on their follow-up plain radiographs and computerized tomography in follow-up interval. CONCLUSIONS: For the patients who suffer from the unstable bursting atlantal fracture, the nonoperative methods could carry some clinical complications including infection, nerve injury, etc. and is frequently failure, Posterior atlantoaxial fusion using bilateral atlas laminar hook combined with transarticular screw fixation is an effective treatment.

[Clinical contrast of percutaneous pinning with plaster splint and open reduction and pulling out wire in the treatment of mallet fingers].

OBJECTIVE: To compare differences in the clinical outcomes between percutaneous pinning with plaster splint and open reduction and pulling out wire in the treatment of mallet fingers. METHODS: From December 2002 to September 2007, 72 patients with mallet fingers were treated. They were divided into two groups: group A and group B. In group A, 38 patients were treated by open reduction and pulling out wire, 34 males and 4 females, aged (26.0 +/- 8.5) years. Among them, 2 patients were injured in the index finger, 11 in the middle finger, 18 in the ring finger and 7 in the little finger. Thirty-three patients suffered from sports injuries, 5 from falling wounds. The average time between the injury and the surgery was (6.1 +/- 3.1) days. In group B, 34 patients were treated by percutaneous pinning with plaster splint, 26 males and 8 females, aged (28.1 +/- 10.7) years. Among them, 1 patient was injured in the index finger, 9 in the middle finger, 15 in the ring finger and 9 in the little finger. Thirty-one patients suffered from sports injuries, 3 from falling wounds. The average time between the injury and the surgery was (6.3 +/- 3.6) days. All the fingers had typical mallet malformation, and X-ray films showed avulsed fractures of distal-segment phalanxes at the dorsal basilar part. RESULTS: The operation time was (61.8 +/- 12.8) minutes in group A and (7.0 +/- 2.6) minutes in group B. All patients in both groups were followed up for 6-24 months (11.9 months on average in group A and 13.2 months in group B). In group A, apart from 3 patients who had flap necrosis and infection, all the other patients obtained healing by first intention. One patient had palmar skin ulcer at 6 days after the operation and healed after proper treatment. Thirty-six patients gained bone union at (47.6 +/- 8.7) days postoperatively and 2 patients had pseudarthrosis, which improved after reconstruction of the extensor tendon attachment point. According to the total active movement (TAM) functional assessment system, 10 cases were excellent, 18 good, 8 fair and 2 poor, with the choiceness rate of 73.7%. In group B, all incisions obtained healing by first intention without pin-track infection, flap necrosis and migration of the pins and gained bone union at (27.7 +/- 3.9) days after the operation. According to the TAM functional assessment system, 19 cases were excellent, 13 good and 2 fair, with the choiceness rate of 94.1%. There were significant differences between the two groups in operation time, complications, healing time and choiceness rate (P < 0.05). CONCLUSION: Percutaneous pinning with plaster splint is simple in operation and has smaller incisions and fewer complications compared withopen reduction and pulling out wire, and proves to be a useful way in the treatment of mallet fingers.