Carpal bone replacement using personalized 3D printed tantalum prosthesis.

Objective: Scaphoid and lunate fractures have a relatively high incidence rate. Traditional carpectomy and carpal arthrodesis in the treatment of carpal osteonecrosis will lead to many complications. Three-dimensional (3D) printed tantalum has good biocompatibility and can be designed to match the patient's personalized anatomical carpal structure. This study aims to investigate carpal function and prosthesis-related conditions after carpal bone replacement using 3D printed tantalum prostheses. Methods: From July 2020 to January 2022 at our center, seven patients with osteonecrosis of the carpus received carpal bone replacement using 3D printed tantalum prosthesis. The Disability of the Arm, Shoulder and Hand (DASH) score and patient satisfaction, as well as the Mayo Wrist Scores (Cooney method, modified Green, and O'Brien wrist score), were used to evaluate the preoperative and postoperative wrist function of patients. The Visual Analog Scale (VAS) pain scores were also recorded before and after surgery. The angles of flexion, dorsiflexion, ulnar deviation, and radial deviation were measured using an arthrometer. The grip strength and pinch strength of the operated hand after carpal bone replacement and the contralateral healthy carpus were measured using a dynamometer. Radiographs were taken to confirm the condition and complications of the tantalum prosthesis. Results: All seven patients were followed for 19.6 ± 2.7 months. At the last follow-up, the grip strength of the operated wrist joint after carpal bone replacement was 33.4 ± 2.3 kg, the pinch strength was 8.9 ± 0.7 kg, the flexion was 54.6° ± 0.8°, the dorsiflexion was 54.7° ± 1.7°, the ulnar deviation was 34.6° ± 1.9°, and the radial deviation was 25.9° ± 0.8°, all of which showed no statistically significant difference with the contralateral healthy carpus (p > 0.05). There were significant differences in the VAS, DASH, and MAYO scores between the preoperative and the last follow-up (p < 0.01). Patients had reduced postoperative pain and improved wrist function and range of motion (ROM), and the tantalum prostheses were stable. Conclusion: The 3D printed tantalum brings us new hope, not only for hip or knee replacement, but also for joint replacement of other complex anatomical structures, and patients with other irregular bone defects such as bone tumors and deformity, which could realize personalized treatment and precise medicine.

Is Valgus Cut Angle Based on Radiographic Measurements in Total Knee Arthroplasty Really Inaccurate? A Comparison of Two- and Three-Dimensional Measurements.

Radiographs are widely used to measure distal femoral valgus cut angle (VCA) in total knee arthroplasty (TKA), but its accuracy is controversial. This study used three-dimensional (3D) reconstruction models to verify the accuracy of VCA measurements on radiographs, and explore the correlation of VCA with hip-knee-ankle (HKA) angle and lateral femoral bowing angle (FBA). A total of 444 osteoarthritis knees of 444 patients from August 2016 to June 2018 was included retrospectively. On radiographs, two-dimensional VCA (VCA-2D) was measured between the femoral mechanical axis and the distal femoral anatomical axis, and HKA was measured between the femoral mechanical axis and the tibial mechanical axis. On the coronal projection of computed tomography 3D models, the anatomical landmarks used for VCA-3D measurements were the same as those on the radiographs, FBA was measured between the proximal and distal femoral anatomical axis. The distributions of VCA-2D and VCA-3D were evaluated by means and variances. The correlation between HKA and VCA and between FBA and VCA was explored. There was a statistical difference between VCA-2D and VCA-3D (p < 0.001), but the deviation was very small (0.15 ± 0.69 degrees), 83.3% of the deviations were less than 1 degree. VCA would increase both in 2D and 3D with increasing of FBA and HKA varus. There was no statistically significant difference between VCA-2D and VCA-3D in patients with moderate varus knees (0-8 degrees of varus) and mild bowing femurs (FBA <5 degrees). Overall, the deviation caused by using radiography to measure VCA was negligible. VCA measurements using radiographs were accurate in patients with moderate varus knees and mildly bowed femurs. This study reflects level of evidence III.

Highly Porous 3D Printed Tantalum Scaffolds Have Better Biomechanical and Microstructural Properties than Titanium Scaffolds.

OBJECTIVE: To test the biomechanical properties of 3D printed tantalum and titanium porous scaffolds. METHODS: Four types of tantalum and titanium scaffolds with four alternative pore diameters, #1 (1000-700 µm), #2 (700-1000 µm), #3 (500-800 µm), and #4 (800-500 µm), were molded by selective laser melting technique, and the scaffolds were tested by scanning electronic microscope, uniaxial-compression tests, and Young's modulus tests; they were compared with same size pig femoral bone scaffolds. RESULTS: Under uniaxial-compression tests, equivalent stress of tantalum scaffold was 411 ± 1.43 MPa, which was significantly larger than the titanium scaffolds (P < 0.05). Young's modulus of tantalum scaffold was 2.61 ± 0.02 GPa, which was only half of that of titanium scaffold. The stress-strain curves of tantalum scaffolds were more similar to pig bone scaffolds than titanium scaffolds. CONCLUSION: 3D printed tantalum scaffolds with varying pore diameters are more similar to actual bone scaffolds compared with titanium scaffolds in biomechanical properties.

Scaffold With Natural Calcified Cartilage Zone for Osteochondral Defect Repair in Minipigs.

BACKGROUND: Long-term outcomes of current clinical interventions for osteochondral defect are less than satisfactory. One possible reason is an ignorance of the interface structure between cartilage and subchondral bone, the calcified cartilage zone (CCZ). However, the importance of natural CCZ in osteochondral defects has not been directly described. PURPOSE: To explore the feasibility of fabricating trilayer scaffold containing natural CCZ for osteochondral defects and the role of CCZ in the repair process. STUDY DESIGN: Controlled laboratory study. METHODS: The scaffold was prepared by cross-linking lyophilized type II collagen sponge and acellular normal pig subchondral bone with or without natural CCZ. Autologous bone marrow stem cells (BMSCs) of minipig were mixed with type II collagen gel and injected into the cartilage layer of the scaffold before operation. Thirty minipigs were randomly divided into CCZ (n = 10), non-CCZ (n = 10), and blank control (n = 10) groups. An 8 mm-diameter full-thickness osteochondral defect was created on the trochlear surface, and scaffold containing BMSCs was transplanted into the defect according to grouping requirements. At 12 and 24 weeks postoperatively, specimens were assessed by macroscopic observation, magnetic resonance imaging examination, and histological observations (hematoxylin and eosin, Safranin O-fast green, type II collagen immunohistochemical, and Sirius red staining). Semiquantitative cartilage repair scoring was conducted using the MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) system and the O'Driscoll repaired cartilage value system. RESULTS: The defects in the blank control and non-CCZ groups were filled with fibrous tissue, while the cartilage layer of the CCZ group was mainly repaired by hyaline cartilage at 24 weeks postoperatively. The superior repair outcome of the CCZ group was confirmed by MOCART and O'Driscoll score. CONCLUSION: The trilayer scaffold containing natural CCZ obtained the best repair effect compared with the non-CCZ scaffold and the blank control, indicating the importance of the CCZ in osteochondral tissue engineering. CLINICAL RELEVANCE: This study demonstrates the necessity to reconstruct CCZ in clinical osteochondral defect repair and provides a possible strategy for osteochondral tissue engineering.

Treatment of massive iliac chondrosarcoma with personalized three-dimensional printed tantalum implant: a case report and literature review.

Although customized three-dimensional tantalum implants have been used to treat a large variety of diseases, few reports have described the application of such implants to reconstruct large pelvic bone defects after the removal of massive tumors. We herein describe a 30-year-old woman with a 9-year history of a massive low-grade chondrosarcoma in the pelvic bone. After removal of a solid 12- × 8- × 6-cm tumor with clear margins, we used a customized three-dimensional printed tantalum implant to fill the large pelvic bone defect and performed hip arthroplasty in a one-step surgery. The patient's postoperative recovery was uneventful. She started walking 1 month after surgery, and she developed no tumor recurrence, instrumentation failure, or implant loosening during the 12-month follow-up period. This report describes the successful application of a customized three-dimensional printed implant to reconstruct a massive pelvic bone defect. Satisfactory functional recovery was achieved with no apparent complications. The methodology of the current case may benefit orthopedic and oncologic surgeons in designing treatment strategies for similar cases.

Gait Analysis after Total Knee Arthroplasty Assisted by 3D-Printed Personalized Guide.

BACKGROUND: With the development of three-dimensional printing (3DP) technology, the patient-specific instrumentation (PSI) has been widely applied in total knee arthroplasty (TKA). The purpose of this study was to compare the gait parameters of patients with 3DP personalized guide-assisted and standard TKA. METHODS: Retrospective analysis of the advanced knee OA cases in our hospital between June 2017 and June 2018 was conducted. 30 cases received 3DP personalized guide-assisted TKA (group A), and 60 patients who underwent standard TKA during the same period were in group B and group C according to the computed tomography (CT) measurement results, each with 30 cases. Hip-knee-ankle angle (HKA), patella transverse axis-femoral transepicondylar axis angle (PFA), and gait parameters were statistically analyzed. The function was assessed by Hospital for Specific Surgery (HSS) and Knee Society Score (KSS). RESULTS: The mean follow-up period was 12.3 months in the three groups. The knee max flexion angle at the swing phase of group A was larger than group B and group C (P < 0.05), there was no statistically significant difference in other gait parameters. The mean PFA of group A was smaller than that of group B and group C (P < 0.05). While, the HKA, HSS, and KSS scores of three groups showed no significant difference. CONCLUSION: 3DP personalized guide technology could improve the gait parameters after surgery, specifically reflected in the knee max flexion angle at the swing phase. It could also assist in the reconstruction of more accurate patellar tracking and rotational alignment in TKA, avoiding the occurrence of insufficient or excessive extorsion.

Accuracy of a Novel 3D-Printed Patient-Specific Intramedullary Guide to Control Femoral Component Rotation in Total Knee Arthroplasty.

OBJECTIVE: Total knee arthroplasty (TKA) is one of the most universal and effective means for treating terminal stage osteoarthritis (OA) of knee. Accurate intramedullary guide of femur is the basis for the distal femoral cuts. Determining the surgical transepicondylar axis (sTEA) is the key to reconstruction of the femoral rotational alignment, because the correct rotational alignment can place the femoral component in the right position, balance the flexion gap so that the inner and outer tension is equal, get stability during the flexion process of the knee, and enhance the quality of life of patients. With the development of three-dimensional printing (3DP) technology in the medical domain, the application of patient-specific instrumentation (PSI) in arthroplasty has become more common. The aim of this study was to evaluate the accuracy of a novel 3D-printed patient-specific intramedullary guide to control femoral component rotation in TKA. METHODS: Eighty patients (65 females and 15 males) with knee OA were included in this prospective randomized study. The patients were divided into two groups by random number table method, 40 in each group. TKA assisted by PSI (PSI group) and conventional TKA (conventional group) was performed respectively. Clinical outcomes [operation time, postoperative drainage volume, duration of drainage, Hospital for Special Surgery knee score (HSS), American Knee Society knee score (AKS)] and radiological outcomes [hip-knee-ankle angle (HKA), posterior condylar angle (PCA), patella transverse axis-femoral transepicondylar axis angle (PFA), depth of intramedullary guide] were compared between and within the two groups. RESULTS: PSI group had less postoperative drainage volume but longer operation time than the conventional group (P < 0.05). The AKS and HSS scores after surgery were improved compared with those before surgery in each group (P < 0.05). However, there was no significant difference in the duration of drainage and range of motion (ROM) after surgery between the two groups. For the radiological results, the HKA and PFA were improved after surgery in both groups (P < 0.05).The postoperative PFA and PCA of the PSI group were closer to 0°, which was better than that of the conventional group (P < 0.05). The depth of intramedullary guide in the PSI group was less than the conventional group (P < 0.05). But there was no significant difference in HKA before and after surgery between the two groups as well as the preoperative PFA. CONCLUSION: The short-term clinical efficacy of TKA assisted by PSI was similar to the conventional TKA. Although TKA assisted by PSI spent more time during operation, it could assist in intramedullary guide and align femoral rotation more accurately.

The association between anterior femoroacetabular impingement and femoral neck fractures: An observational study.

The impact between acetabulum and femoral neck is another possible mechanism of femoral neck fracture.Direct trauma of the greater trochanter may not be able to fully explain the mechanism underlying femoral neck fracture. In this study, we sought to investigate whether anterior femoroacetabular impingement are associated with femoral neck fractures.A total of 36 patients with femoral neck fracture who had undergone total hip arthroplasty or hemiarthroplasty were included in this study. These patients were divided into 2 groups: labrum tear group and normal labrum group. Patients' age, gender, body mass index, muscle injury, injury pattern, trauma severity, femoral head-neck offset, femoral head-neck ratio, Cam deformity alpha angle, acetabular anteversion, femoral head diameter, acetabular index, cortical index, hip axis length, and neck stem angle were recorded and analyzed. SPSS 18.0 software was used for statistical analyses.According to intraoperative findings, 22 patients exhibited a labrum tear. Magnetic resonance imaging examination revealed bone contusion on the anterolateral margin of the acetabulum with muscle damage surrounding the hip. Among 14 cases without a labrum tear, no bone contusion and obvious muscle injury were found on the anterolateral margin of the acetabulum. Notably, muscle injury, injury pattern, trauma severity and femoral head-neck offset differed significantly (P < .05) between labrum tear and normal labrum groups.Previous studies have focused more on direct lateral trauma. In this study, the impact between acetabulum and femoral neck is another possible mechanism besides lateral impact. Specifically, the abnormal anatomy of the hip, such as femoral head-neck offset, may promote the fracturing process.

Endoscopic Treatment of Symptomatic Foot and Ankle Bone Cyst with 3D Printing Application.

OBJECTIVE: To study the efficacy of arthroscopy for treating symptomatic bone cysts of the foot and ankle through the follow-up of patients and to further explore the application value of 3D printing technology in this treatment. METHODS: Twenty-one patients with symptomatic bone cysts in the foot and ankle who underwent arthroscopic surgery in our Center from March 2010 to December 2018 were enrolled, including 11 in the experimental group and 10 in the control group. For the control group, C-arm fluoroscopy was used intraoperatively to confirm the positioning of the cysts; for the experimental group, a 3D model of the lesion tissue and the 3D-printed individualized guides were prepared to assist the positioning of the cysts. Debridement of the lesion tissues was conducted under an arthroscope. Regular follow-ups were conducted. The time of establishing arthroscopic approaches and the times of intraoperative fluoroscopy between the two groups were compared. Significance was determined as P < 0.05. RESULTS: The postoperative pathology of the patients confirmed the diagnosis. No significant perioperative complications were observed in either group, and no recurrence of bone cysts was seen at the last follow-up. The VAS scores and AOFAS scores of the two groups at the last follow-up were significantly improved compared with the preoperative data, but there was no statistical difference between the two groups. All surgeries were performed by the same senior surgeon. The time taken to establish the arthroscopic approaches between the two groups was statistically significant (P < 0.001), and the times of intraoperative fluoroscopy required to establish the approach were also statistically significant (P < 0.001). The intraoperative bleeding between the two groups was statistically significant (P < 0.01). There was 1 case in each group whose postoperative CT showed insufficient bone grafting, but no increase in cavity volume was observed during the follow-up. CONCLUSION: With the assistance of the 3D printing technology for treating symptomatic bone cysts of the ankle and foot, the surgeon can design the operation preoperatively and perform the rehearsal, which would make it easier to establish the arthroscopic approach, better understand the anatomy, and make the operation smoother. This trial is registered with http://www.clinicaltrials.govNCT03152916.

[Gait analysis after total knee arthroplasty assisted by three-dimensional printing navigation template].

OBJECTIVE: To explore the gait trajectory characteristics of patients after total knee arthroplasty (TKA) assisted by three-dimensional (3D) printing navigation template. METHODS: Twenty female patients (20 knees) with knee osteoarthritis who were treated with TKA assisted by 3D printing navigation template between February 2017 and February 2018 were selected as the 3D printing group. The patients were 50-69 years old, with an average age of 57.2 years. The disease duration was 4-7 years, with an average of 5.6 years. The osteoarthritis was classified as Kellgren-Lawrence Ⅲ level in 5 cases and Ⅳ level in 15 cases. The preoperative hip-knee-ankle angle (HKA) was (170.8±5.6)°. All patients were varus deformity. According to age and affected side, 20 healthy female volunteers were selected as the control group. The volunteers were 51-70 years old, with an average age of 56.7 years. Preoperative HKA was (178.8±0.6)°. There was significant difference in HKA between the two groups ( P>0.05). The HKA, Western Ontario and McMaster University Osteoarthritis Index (WOMAC), and visual analogue scale (VAS) scores of the 3D printing group before and after operation were compared. At 6 months after operation, the gait trajectory characteristics of 3D printing group and control group were analyzed by Vicon gait capture system. The kinematics parameters included velocity, cadence, stride length, maximum knee flexion angle (stance), minimum knee flexion angle (stance), maximum knee flexion angle (swing), mean hip rotation angle (stance), mean ankle rotation angle (stance). RESULTS: The incisions of 3D printing group healed by first intention, with no complications. All patients were followed up 7-12 months (mean, 9.0 months). The WOMAC and VAS scores at 6 months after operation were significant lower than those before operation ( P<0.05). The HKA was (178.8±0.8)° at 4 weeks after operation and the difference was significant when compared with that before operation ( t=39.203, P=0.000). The position of the prosthesis was good. The femoral posterior condyle osteotomy line, surgical transepicondylar axis, and patella transverse line were parallel, varus deformity was corrected, and lower limb alignment was restored to neutral position. Gait analysis at 6 months after operation showed that the differences in all kinematics parameters between the two groups were significant ( P<0.05). CONCLUSION: Assisted by 3D printing navigation template, TKA can alleviate pain symptoms and correct deformity, with satisfactory early effectiveness. Compared with healthy people, the early postoperative gait of the patients were characterized by decreasing velocity, cadence, stride length, knee flexion range, and increasing compensatory hip and ankle rotation range.

Outcomes after Total Hip Arthroplasty Using a Cementless S-ROM Modular Stem for Patients with High Hip Dislocation Secondary to Hip Pyogenic Arthritis.

OBJECTIVE: To evaluate the midterm results of the cementless S-ROM modular femoral stem used with subtrochanteric transverse shortening osteotomy for the treatment of high hip dislocation secondary to hip pyogenic arthritis. METHODS: We retrospectively reviewed the data of 49 patients (49 hips) with an average infection quiescent period of 37.4 years who underwent cementless total hip arthroplasty (THA) with simultaneous subtrochanteric transverse shortening osteotomy from July 2008 to June 2012. There were 23 men and 26 women with a mean age of 44.3 years at the time of surgery. The following clinical outcomes were evaluated: the Western Ontario and McMaster Universities Arthritis Index (WOMAC) score, Harris hip score (HSS), modified Merle d'Aubigne-Postel hip (MAP) score, low back pain visual analog scale score, 12-item short-form health survey questionnaire score, limp, and Trendelenburg sign. Radiographic outcomes and complications were also evaluated. RESULTS: The mean follow-up period was 8.7 years (range, 5.5-10 years). No infection recurrence was observed after THA. The average HSS significantly improved from 45.0 to 84.8. The WOMAC score improved from 70.1 ± 3.5 (range, 65-76) to 43.1 ± 13.4 (range, 21-67). The modified MAP score improved from 5.9 ± 1.9 (range, 3-9) to 14.3 ± 2.4 (range, 11-18). The low back pain visual analog scale score, 12-item short-form health survey questionnaire score, limp, and Trendelenburg sign also improved significantly. The average limb length discrepancy decreased from 39.6 mm (range, 30-55 mm) to 7.2 mm (range, 0-22 mm). Two patients had temporary sciatic nerve paralysis but recovered within 6 months without any functional defects; one had an intraoperative fracture fixed by cerclage wires. One hip required revision surgery because of femoral stem aseptic loosening. CONCLUSIONS: The cementless S-ROM modular femoral stem used with subtrochanteric transverse shortening osteotomy is safe and effective for high hip dislocation secondary to pyogenic arthritis and provides satisfactory midterm results. Significant improvements in clinical function were observed, as were high rates of stable fixation of the cementless implant, restoration of more normal limb lengths, and a low incidence of complications.

Application of 3D-printed Customized Guides in Subtalar Joint Arthrodesis.

OBJECTIVE: To explore the feasibility of 3D printed customized guides assisting the precise drilling of Kirschner wires in subtalar joint arthrodesis. METHODS: We retrospectively reviewed the data of 29 patients (30 subtalar joints) who underwent subtalar joint arthrodesis between 1 July 2013 and 31 December 2017. The customized guides were designed on a full-scale 3D polylactic acid model made from computed tomography (CT) data of patients by Model Intestinal Microflora in Computer Simulation (MIMICS) software, which were manufactured by 3D printing technology. A total of 14 joints used customized guides (experimental group); the remained 16 joints used the traditional method (control group). The time of drilling the Kirschner wires to the correct position, the time of subtalar fusion, American Orthopaedic Foot & Ankle Society (AOFAS) scores, and complications were evaluated in both groups. RESULTS: All customized guides were successfully manufactured. In the experimental group, it took 2.1 ± 0.7 min to drill the Kirschner wire to the satisfactory position, and 2 cases needed to be re-drilled; in the control group, it took 4.6 ± 1.9 min to drill the Kirschner wire to the satisfactory position (P < 0.05), and 8 cases needed to be re-drilled. No serious complications occurred in both groups during and after the surgery. Postoperative radiographic fusion was confirmed in all cases. No significant difference was observed in the fusion time and AOFAS scores 1 year postoperatively between the two groups (P > 0.05). CONCLUSION: It is safe to apply 3D-printed customized guides for subtalar joint arthrodesis, which can assist the accurate drilling of Kirschner wires into the appropriate position according to the preoperative plan, and reduce the operation time as well as intraoperative radiation.

Application of 3D-Printed Personalized Guide in Arthroscopic Ankle Arthrodesis.

OBJECTIVE: To accurately drill the Kirschner wire with the help of the 3D-printed personalized guide and to evaluate the feasibility of the 3D technology as well as the outcome of the surgery. METHODS: Patients' DICM data of ankle via CT examinations were introduced into the MIMICS software to design the personalized guides. Two 2mm Kirschner wires were drilled with the help of the guides; the C-arm fluoroscopy was used to confirm the position of the wires before applying the cannulated screws. The patients who underwent ankle arthrodesis were divided into two groups. The experimental group adopted the 3D-printed personalized guides, while the control group received traditional method, i.e., drilling the Kirschner wires according to the surgeon's previous experience. The times of completing drilling the Kirschner wires to correct position were compared between the two groups. Regular follow-ups were conducted to statistically analyze the differences in the ankle fusion time and AOFAS scores between the two groups. RESULTS: 3D-printed personalized guides were successfully prepared. A total of 29 patients were enrolled, 15 in the experimental group and 14 in the control group. It took 2.2 ± 0.8 minutes to drill the Kirschner wires to correct position in the experimental group and 4.5 ± 1.6 minutes in the control group (p=0.001). No obvious complications occurred in the two groups during and after surgery. Postoperative radiographs confirmed bony fusion in all cases. There were no significant differences in the fusion time (p=0.82) and AOFAS scores at 1 year postoperatively between the two groups (p=0.55). CONCLUSIONS: The application of 3D-printed personalized guide in assisting the accurate drilling of Kirschner wire in ankle arthrodesis can shorten the operation time and reduce the intraoperative radiation. This technique does not affect the surgical outcome. TRIAL REGISTRATION NUMBER: This study is registered on www.clinicaltrials.gov with NCT03626935.

Hemi-arthroplasty performed in a 109-year-old patient with intertrochanteric fracture: A case report.

The mortality of conservative treatment and the risk resulting from operation for elderly patients with femoral intertrochanteric fractures are high. Safety in the perioperative period and quicker recovery should be placed at the top priority for elderly patients with hip fractures. We reported a case of 109-year-old female patient with intertrochanteric fracture who has undergone the hemiarthroplasty in our center recently. With sciatic nerve and lateral cutaneous nerve block anesthesia, she was offered the artificial femoral head replacement in the lumbar plexus block after sufficient preoperative preparation. The surgery went well with minimally invasive cut, and the patient's recovery was satisfactory.

Total hip arthroplasty for patients with Crowe type IV developmental dysplasia of the hip: Ten years results.

BACKGROUND AND OBJECTIVES: The aim of this study was to determine the rate of union, functional results and complications in patients with Crowe IV developmental dysplasia of the hip (DDH) who underwent cementless total hip arthroplasty (THA) with S-ROM prostheses and subtrochanteric transverse shortening osteotomy. METHODS: Forty-five patients (52 hips) operated between January 2005 and May 2008, with a mean age of 40.6 years at surgery were followed. The mean follow-up period was 9.8 years. Clinical outcomes, radiographic outcomes and complications were evaluated. RESULTS: Osteotomy union occurred in 52 of 52 femurs (100%). Mean Harris hip score improved from 33.7 ± 4.7 preoperatively to 81.2 ± 6.3, 90.8 ± 5.3 and 89.8 ± 7.1 at 1, 5 and 10 years postoperatively. Two patients had temporary sciatic nerve paralysis postoperatively, and 2 patients experienced early postoperative dislocation. Two patients complained about mild longer limb length than the non-operated limb at the last follow-up. Three hips showed osteolysis in Gruen zone 1, and 1 hip showed osteolysis in zone 1 and 7. No implants were revised, and no signs of component loosening and migration were observed at the last follow-up visit. CONCLUSIONS: S-ROM stem combined with transverse subtrochanteric shortening osteotomy in THA for patients with Crowe type IV DDH has good clinical results with small risk of complications.