Comparison of 3D Printing Rapid Prototyping Technology with Traditional Radiographs in Evaluating Acetabular Defects in Revision Hip Arthroplasty: A Prospective and Consecutive Study.

OBJECTIVE: To compare rapid prototyping technology (RP tech) in revision total hip arthroplasty (RTHA) with traditional examination methods and to see how they are different in evaluating acetabular anatomy and designing surgical procedure. METHODS: From February 2014 to March 2018, 43 RTHA patients with complex acetabulum defects were enrolled in this prospective study regardless of age or gender. Incomplete and unclear data were excluded. Three types of radiographic examination were performed on each patient before the revision surgery. Four groups of evaluations were designed: (i) X-ray; (ii) computed tomography (CT-scan); (iii) RP tech; and (iv) CT-aided RP tech. Discrepancies between preoperative radiographic analysis and intra-operative findings were separately compared by a team of surgeons. Premade surgical plans based on each evaluation method were compared with the final surgical procedure. The compliance of anatomic evaluation and surgical plan-design based on 3D RP tech and traditional radiographs were ranked manually by a of team surgeons into: (i) complete accordance; (ii) general accordance; and (iii) undetermined structure/procedure. The difference in ranks between RP tech and traditional radiographic methods were analyzed with a nonparametric Kruskal-Wallis test. P < 0.05 was considered significant. Multiple adjustments were taken for the statistical tests level according to the Bonferroni method. RESULTS: For anatomic analysis, the accordance in four groups of evaluating methods differed from each other (P < 0.05) except for the comparison of RP tech and CT-aided RP tech. RP tech displayed better anatomic evaluating accuracy than traditional methods (X-ray and CT) with the "complete accordance" rates of these groups being 88.37%, 4.65% and 27.91%, respectively. But CT-aided RP tech did not improve accuracy significantly compared with using RP tech individually, although the value seems high in the CT-aided RP group with the "complete accordance" rate of 95.35%. For surgery design, RP tech significantly showed better applicable surgical design compared with X-ray and CT (P < 0.05), and the "complete accordance" rates were 88.37%, 6.98% and 23.26%, but no significant difference was observed between RP tech and CT-aided RP tech, and the "complete accordance" rate of CT-aided RP tech group was 97.67%. RP tech showed remarkable improvement in bone defect assessment and surgical plan design. CONCLUSION: Using RP technology improved both sensibility and accuracy in acetabular defect evaluation with better locating and evaluating efficiency compared with X-ray and CT-scans. It also improved surgical schedule designing in complex acetabular defecting revision surgery. In particularly complex cases, CT aided RP tech may increase the accuracy of RP tech.

Does mobile-bearing have better flexion and axial rotation than fixed-bearing in total knee arthroplasty? A randomised controlled study based on gait.

OBJECTIVE: To analyse the 6 degrees of freedom of the knee and gait data of patients with medial knee osteoarthritis before and after fixed-bearing (FB) and mobile-bearing (MB) total knee arthroplasty (TKA) â€‹and examine the influence of TKA on gait characteristics and the difference between FB and MB prosthesis. We also sought to explore the prosthesis options available for TKA in these patients. METHODS: Thirty patients who underwent TKA at the Department of Orthopedics at our hospital from June to October 2017 were included. All patients had a lower limb mechanical axis (hip-knee-ankle angle) of less than 180° which were regarded as genu varum knees and had medial knee osteoarthritis. Patients were randomised divided into the FB group â€‹and the MB group according to the knee prosthesis implanted. An infrared navigation three-dimensional portable knee motion analysis system (Opti-Knee®, Shanghai Innomotion, Inc.) was used to acquire data on the 6 degrees of freedom of both knees when walking on flat ground before and after surgery (angle of tibia relative to femur parameters: flexion-extension, internal rotation-external rotation, abduction-adduction; displacement parameters: anterior-posterior, proximal-distal, medial-lateral). Postoperative follow-up efficacy was assessed using the Oxford Knee Score system. RESULTS: There were significant differences in the maximum values of the internal/external rotation and flexion/extension angle between patients post-TKA and the healthy population, p values were 0.007 and <0.001,respectively. The postoperative maximum values of genu varum and internal rotation in both FB [(-9.49 â€‹± â€‹5.99°), (-5.77 â€‹± â€‹3.42°), respectively] and MB [(-9.64 â€‹± â€‹4.83°), (-7.54 â€‹± â€‹4.51°), respectively] groups were lower than the preoperative ones [FB (-15.13 â€‹± â€‹6.78°), (-8.28 â€‹± â€‹4.83°); MB (-13.28 â€‹± â€‹3.98°), (-9.46 â€‹± â€‹4.99°), respectively] (p â€‹≤ â€‹0.001), while the postoperative maximum values of flexion angle and anterior displacement in both FB [(46.11 â€‹± â€‹4.14°), (0.71 â€‹± â€‹0.35 â€‹cm), respectively] and MB [(49.33 â€‹± â€‹3.98°), (0.75 â€‹± â€‹0.89 â€‹cm), respectively] groups were larger than the preoperative ones [FB (43.15 â€‹± â€‹3.77°), (0.26 â€‹± â€‹0.74 â€‹cm); MB (44.62 â€‹± â€‹5.92°), (0.33 â€‹± â€‹0.79°), respectively] (p â€‹≤ â€‹0.001). The postoperative range of flexion/extension angle in both FB (40.13 â€‹± â€‹4.14°) and MB (45.82 â€‹± â€‹3.76°) groups was significantly larger than the preoperative one [FB (36.17 â€‹± â€‹6.07°), MB (37.09 â€‹± â€‹3.93°), respectively] (p â€‹≤ â€‹0.001). There were also significant increases in range of anterior-posterior displacement in the FB group (0.85 â€‹± â€‹0.32 â€‹cm) postoperatively compared with the preoperative one (0.71 â€‹± â€‹0.92 â€‹cm) (p â€‹= â€‹0.016) â€‹and significant increases in range of medial-lateral displacement (0.64 â€‹± â€‹0.73 â€‹cm) in the MB group postoperatively compared with the preoperative one (0.52 â€‹± â€‹0.91 â€‹cm) (p â€‹= â€‹0.025). The mean flexion/extension angle of the MB group was significantly greater than the FB group after surgery in both the stance phase and the swing phase (p â€‹< â€‹0.001). There were significant differences in postoperative knee axial rotation during the gait cycle between the MB and FB groups (p â€‹= â€‹0.028) â€‹and that postoperative internal rotation of the tibia relative to the femur increased in the MB group. The Oxford Knee Score at the last follow-up visit about 7.5 months after surgery was 15.6 â€‹± â€‹1.3 and 15.1 â€‹± â€‹1.1 points for FB and MB groups, respectively. This difference was not significant (p â€‹= â€‹0.428). CONCLUSIONS: TKA can make the parameters of knee gait characteristics closer to the normal population. Medial knee osteoarthritis patients who received a MB prosthesis in TKA had better joint flexion function and axial rotation than the FB one. However, there is insufficient evidence to suggest that the MB prosthesis is a better option for patients with medial knee osteoarthritis. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: To date, no consensus for prosthesis selection in TKA has been established. This study found significant differences in joint flexion/extension angle and internal/external rotation during gait post-TKA surgery in medial knee osteoarthritis patients who received different prostheses. This will provide some references for prosthesis selection for a large number of genu varum patients in clinical practice.

Effect of Femoral Component Flexion Implantation on the Mediolateral Bone-prosthetic Fit in Total Knee Arthroplasty.

OBJECTIVE: Femoral component overhang in total knee arthroplasty (TKA) has been reported in previous studies. The purpose of this study was to evaluate the effect of femoral component flexion implantation on mediolateral bone-prosthetic fit in TKA. METHODS: Virtual prosthesis implantations were performed on computed tomographic models of 10 Chinese knees with femoral prostheses of the Advance Medial-Pivot knee system (MicroPort Orthopedics, Arlington, TN, USA), with the femoral component positioned at 0°, 3°, or 6° of flexion in the sagittal plane. For each degree of flexion implantation, the differences between the knee and femoral component models on the lateral and medial sides at trochlea (zone 1), anterior-distal condyle (zone 2), posterior-distal condyle (zone 3), and posterior condyle (zone 4) were measured. Positive difference values indicate component overhang, and negative difference values indicate component underhang. The values of component overhang (underhang) in each zone were statistically analyzed across the 3° of flexion implantation. RESULTS: With a greater degree of flexion implantation, overhang was reduced and even changed to underhang. With 0° of flexion implantation, an overhang exceeding 3 mm existed mainly on the medial side of zone 1 (5.81 mm) and the lateral side of zone 2 (3.39 mm). With 3° of flexion, overhang exceeding 3 mm was observed only on the medial side of zone 1 (3.10 mm), and underhang was observed only on the medial side of zone 4 (-0.32 mm). No overhang exceeding 3 mm was observed for 6° of flexion, while underhang was observed except on the lateral sides of zone 2 (1.32 mm) and zone 4 (1.10 mm) and on the medial side of zone 1 (1.54 mm). A significant difference in overhang values on the lateral and medial sides of zone 1 was observed between 0 and 6° of flexion (P < 0.05). CONCLUSION: The present study demonstrated that femoral component flexion implantation by 3° can reduce excessive overhang, although 3.10 mm of overhang remained at the medial side of zone 1. Conversely, 6° of flexion implantation can avoid 3 mm of overhang for any zone, but increases the risk of underhang. Slight flexion implantation may be an effective alternative technique to prevent excessive component overhang, especially in the trochlea and anterior region of the distal condyle, in Chinese patients with standard TKA prostheses.

Comprehensive treatment for gas gangrene of the limbs in earthquakes.

BACKGROUND: Mortality rates for patients with gas gangrene from trauma or surgery are as high as 25%, but they increase to 50%-80% for patients injured in natural hazards. Early diagnosis and treatment are essential for these patients. METHODS: We retrospectively analyzed the clinical characteristics and therapeutic results of 19 patients with gas gangrene of the limbs, who were injured in the May 2008 earthquake in the Wenchuan district of China's Sichuan province and treated in our hospital, to seek how to best diagnose and treat earthquake-induced gas gangrene. RESULTS: Of 226 patients with limbs open injuries sustained during the earthquake, 53 patients underwent smear analysis of wound exudates and gas gangrene was diagnosed in 19 patients. The average elapsed time from injury to arrival at the hospital was 72 hours, from injury to definitive diagnosis was 4.3 days, and from diagnosis to conversion of negative findings on wound smear analysis to positive findings was 12.7 days. Anaerobic cultures were also obtained before wound closure. The average elapsed time from completion of surgery to recovery of normal vital signs was 6.3 days. Of the 19 patients, 16 were treated with open amputation, two with closed amputation, and 1 with successful limb salvage; 18 patients were successfully treated and one died. CONCLUSIONS: In earthquakes, rapid, accurate screening and isolation are essential to successful treatment of gas gangrene and helpful in preventing nosocomial diffusion. Early and thorough debridement, open amputation, and active supportive treatment can produce satisfactory therapeutic results.

Reconstruction of peri-implant bone defects using impacted bone allograft and BMP-2 gene-modified bone marrow stromal cells.

Impaction bone allografting represents an attractive procedure for bone defects reconstruction in joint replacement. And it was found that bone morphogenetic protein-2(BMP-2) gene therapy can enhance bone healing. The purpose of this study was to determine if combined adenovirus mediated human BMP-2(Adv-hBMP-2) gene-modified bone marrow stromal cells(BMSCs) with allograft enhanced the defects healing and improved the strength of implant fixation in 3-mm bone defect around a titanium alloy implant. Using the impaction grafting technique, the defects were reconstructed using freeze-dried allograft, freeze-dried allografts loaded with autogenous BMSCs, or freeze-dried allografts loaded with autogenous BMSCs modified with the human bone morphogenetic protein-2 (hBMP-2) gene. At 6 and 12 weeks, the Bone-implant Contact rate and strength of the interface in the group with BMP-2 gene medication were significantly higher than those of the non-cell or cell groups. BMP-2 gene medication also showed significant effects on allograft healing and replacement compared with those of two other groups, as evidenced by increased new bone formation and reduced graft remnants. The results suggest that BMP-2 gene medication can enhance allograft healing and osseointegration of the bone-implant interface.

Computer-aided custom-made hemipelvic prosthesis used in extensive pelvic lesions.

We review here our experience in the computer-aided design and manufacture and implantation of custom-made hemipelvic prostheses in 10 patients who underwent internal hemipelvectomy for extensive pelvic lesions. Computed tomography data and the rapid prototyping technique were used to make a precise model of each patient's pelvis for the simulated hemipelvectomy; the model was used to design and manufacture prostheses that were easy to implant because the location and orientation of the acetabulum was readily adjustable. Four patients died 6 to 10 months after surgery; the remaining 6 patients, monitored for 21 to 48 months, all had good hip function. There were early hip dislocations in 2 patients and wound-healing problems in 3, but all were treated successfully.

[Total hip arthroplasty for Crowe type-IV development dysplasia of hip in adults].

OBJECTIVE: To determine the operation procedure of total hip arthroplasty (THA) for Crowe type-IV developmental dysplasia of hip and its relationship with nerve injury. METHODS: A consecutive series of 39 THAs was performed for Crowe type-IV developmental dysplasia of hip in 35 patients (all female). The mean age of the patients at the time of surgery was 46 years (range 36 - 56 years). Thirty-five hips in 31 patients were followed up. The average follow-up period of the whole series was 4 years (range 1 - 8 years). All procedures were carried out through a lateral-posterior approach. In 33 of 35 hips, the cup was inserted in the "true" acetabulum. All the prostheses used were cementless, except for 5 cemented femoral stems in 5 patients. Each patient was evaluated clinically and by radiographs before the operation and during the follow-up period, according to the Harris hip score (HHS). RESULTS: None of the cups and stems were revised for aseptic loosening, dislocation or infection during the follow-up period. The mean preoperative HHS was 43 compared with the postoperative HHS of 87. The mean amount of postoperative leg lengthening was 5 cm (range 4 - 6 cm). CONCLUSIONS: The reconstruction of the hip at the level of the "true" acetabulum through a lateral-posterior approach is a safe and effective procedure of THA for Crowe type-IV developmental dysplasia of hip in adults. Acute leg lengthening of less than 6 cm could not cause nerve injury.

[Effects of bone morphogenetic protein-2 gene therapy on the bone-implant interface: an experimental study with dogs].

OBJECTIVE: To investigate the effects of bone morphogenetic protein-2 (BMP-2) gene therapy on the bone-implant interface in the reconstruction of periprosthetic bone defect. METHODS: Transverse defects were caused in the external condylae of both femurs of 14 adult Beagle dogs. Titanium alloy implants were inserted and a bone defect 3 mm wide around the titanium alloy implant was preserved. Then the total 28 defects were divided into 4 groups: 8 bone defects remained untreated (blank control group); 8 bone defects were implanted with heterogeneous freeze-dried bone by impaction grafting technique (non-cell group); 8 bone defects were implanted with heterogeneous freeze-dried bone loaded with autogenous bone marrow stromal cells (BMSCs) from the greater trochanter of the same dog (cell group); and 10 bone defects were implanted with freeze-dried allograft loaded with autogenous BMSCs from the greater trochanter of the same dog which were transfected by Adv-BMP-2 gene (gene group). Three, 6, and 12 weeks after implantation X-ray examination was carried out to observe the place of the implant and the absorption of the implants. Six and 12 weeks after the dogs were killed and their bone defects were taken out to undergo histological, histomorphometric and biomechanical examination to observe the healing and oseeointegration of the bone-implant interface. RESULTS: Histological examination showed that 6 weeks after implantation new bone formation was found on the implant surface and there was point contact between the bone and implant in the gene group with the bone-to-impact contact (BIC) of about 10%; and continuous soft tissue was found at bone-implant interface in all other groups. Twelve weeks after, there was thick soft tissue membrane between the new bone and implant in the blank control group; most of the interface was connective fibrous tissue in the non-cell group and cell group with point contact between the bone and implant and a BIC lower than 10%; and in the gene group the interface consisted mainly of bone tissue and continuous bone-implant contact was found with the BIC of 50%, significantly higher than those of the other 2 groups (both P < 0.01). The mechanical strength of interface increased time-dependently in all groups, that of the gene group being significantly higher than those of the other 2 groups at any time-points (both P < 0.01). CONCLUSION: BMP-2 gene therapy can improve the osseointegration of bone-implant interface.