Correction: Chondroitin sulfate-polydopamine modified polyethylene terephthalate with extracellular matrix-mimetic immunoregulatory functions for osseointegration.

Correction for 'Chondroitin sulfate-polydopamine modified polyethylene terephthalate with extracellular matrix-mimetic immunoregulatory functions for osseointegration' by Ya-Min Li et al., J. Mater. Chem. B, 2019, 7, 7756-7770, DOI: 10.1039/C9TB01984G.

Chondroitin sulfate-polydopamine modified polyethylene terephthalate with extracellular matrix-mimetic immunoregulatory functions for osseointegration.

Optimal integration between the polyethylene terephthalate (PET) graft and host bone is a prerequisite to obtain a satisfactory outcome after graft implantation for ligament reconstruction. Recent studies indicate that complex biosignals including immunoregulation, cell recruitment, and osteogenic differentiation provided by the extracellular matrix (ECM) are conducive to promoting osseointegration. In the present study, a chondroitin sulfate (CS)/polydopamine-modified PET graft was developed to regulate the local immune microenvironment, guide stem cell behavior, and promote new bone formation. We found that CS-modified PET grafts significantly regulated the macrophage phenotype switching from M1 to M2 and promoted the expression of pro-repair cytokines including interleukin (IL)-4, IL-10 and transforming growth factor (TGF)-ß1. Moreover, the immunoregulatory function of CS-modified PET guided stem cell behaviors, including recruitment, adhesion, and proliferation, and enhanced the osteogenic differentiation of stem cells. In vivo experiments confirmed that CS-modified PET switched the local immune microenvironment status from pro-inflammatory to anti-inflammatory, up-regulated osteogenic marker expression, and promoted the bone regeneration process, so as to achieve graft-bone osseointegration. These results indicate that an ECM-biomimetic immunoregulatory coating is an effective approach to promote graft integration. This study proposes an effective strategy for an artificial graft to achieve graft-bone osseointegration through immunoregulatory osteogenesis.

The radiological research for pelvis asymmetry of unilateral developmental dysplasia of the hip in adult.

OBJECTIVES: To investigate whether adult patients with unilateral developmental dysplasia of the hip (UDDH) have pelvic asymmetry and what correlation existing between them. Methods: A total of 100 adult patients with UDDH were enrolled in the retrospective observational study in Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, China, between January 2012 and February 2014. The anteroposterior pelvic radiographs were reviewed and the pelvic heights and ischium heights were measured and compared between the affected and non-affected sides to find out the relationship between the pelvic morphology and hip dysplasia. Results: The pelvic heights demonstrated significant differences between the non-affected side and the affected side in patients with Crowe type II-IV UDDH (p less than 0.05), but not in patients with Crowe type I UDDH (p=0.09). There were significant differences in the bilateral ischium heights in patients with Crowe type III and IV UDDH (p less than 0.05), but not in patients with Crowe type I and II UDDH (p=0.78, p=0.055). In addition, the degree of hip dysplasia was positively associated with the degrees of asymmetry of pelvis (r=0.78, p less than 0.001) and ischium (r=0.72, p less than 0.001) in UDDH patients. Conclusion: The pelvic asymmetry exists in adult patients with UDDH. In addition, the degree of asymmetry has correlation with the degree of hip dysplasia. We recommend that it should be taken more cautions to use teardrops and ischial tuberosity as anatomy landmarks to balance leg-length discrepancy for unilateral DDH patients in preoperative planning and total hip arthroplasty.

Anatomical references for tibial sagittal alignment in total knee arthroplasty: a comparison of three anatomical axes based on 3D reconstructed CT images.

BACKGROUND: This study was designed to analyze three tibial axis reference lines including the anterior tibial cortex (ATC) line, the fibular line (FL), and the anatomical axis of tibia (AAT) line, to determine which line most closely parallels the mechanical axis (MA) of the tibia in the sagittal plane. The clinical relevance of the study is that through finding a reliable landmark on the leg, a surgeon may minimize posterior tibial slope measurement errors thereby and improving the technique for assuring proper alignment of total knee arthroplasty. METHODS: The material for this study included CT scans of the tibia from 85 consecutive patients and 168 knees (78 without osteoarthritis (OA) and 90 knees with OA). Measurements of the angles between the tibial mechanical axis and each of three reference lines in the sagittal plane were carried out using 3D imaging software. RESULTS: Mean angles of 168 knees were as follows: aMT (3.96±0.85)°, aMF (0.70±0.58)°, and aMA (1.40±0.66)°, (aMT: an angle between MA and ATC, aMF: an angle between MA and FL, aMA: an angle between MA and AAT. All abovementioned angles were measured in the sagittal plane of tibia) and the aMF was significantly smaller than the others (P < 0.0001). The mean value of the medial tibial slope angle vs. the MA was (9.19±3.97)°, and this was significantly larger than the mean lateral slope angle of (6.62±4.23)° (P < 0.0001). The difference between aMF without OA and with OA was not statistically significant (P = 0.5015) and the association between the aMT and aMA was strong (r = 0.82, P < 0.01). CONCLUSIONS: FL was more closely parallel to the MA of tibia, and more showed less variation between OA and non- OA controls than ATC and AAT lines. Furthermore, the amount of posterior slope in medial plateau was greater than that in lateral plateau. The findings of this analysis suggest that when using the anterior tibial cortex line as is commonly done with extramedullary tibial resection guides, the tibial resection should be sloped approximately four degrees more posteriorly.

[Cementless total hip arthroplasty for the management of advanced tuberculous coxitis].

OBJECTIVE: The question of whether a total joint arthroplasty should be attempted in a patient with a current or previous infection of tuberculosis continues to arouse controversy. The aim of this report was to evaluate the clinical outcomes of cementless total hip arthroplasty for the treatment of advanced tuberculosis of hip. METHODS: A total of 14 patients with advanced tuberculosis of hip treated by cementless total hip arthroplasty were retrospectively analyzed. For the patients with a definite diagnosis of tuberculosis and elevated levels of CRP (C-reactive protein) and ESR (erythrocyte sedimentation rate) before surgery, preoperative antituberculous medications were prescribed for at least 2 weeks. The inflamed soft tissues and destroyed bones were completely curetted out at the time of operation. Twelve of 14 patients received one-stage cementless total hip arthroplasty after a thorough debridement. For the remaining 2 patients, two-stage strategy was taken with cement articulating spacer implanted after a thorough debridement and followed by cementless total hip arthroplasty at 6-8 months later. All patients were prescribed antituberculous medications postoperatively for the first 6 months. RESULTS: The mean Harris Hip Score (HHS) was 36 preoperatively and 87 at the last follow-up. Within an average follow-up period of 49 months (range: 27 - 77), only one patient had reactivation of tuberculosis 7 months after primary THA (total hip arthroplasty) and received resection arthroplasty. Another 13 patients had no reactivation of tuberculosis and revealed stability by bone ingrowth on both socket and femoral stem. CONCLUSION: Cementless total hip arthroplasty is a safe and effective procedure for advanced tuberculosis of hip. With a thorough debridement followed by a complete course of antituberculous chemotherapy, active tuberculous infection should not be considered a contraindication for THA. In patients whose diagnosis of tuberculosis is confirmed intraoperatively and with no preoperative antituberculous chemotherapy, or in those a thorough debridement can not be achieved, a two-stage surgery may be considered.

[Cementless two-staged total hip arthroplasty for chronic periprosthetic infection].

OBJECTIVE: To determine the clinical outcomes of two-staged cementless revision arthroplasty for the treatment of deep periprosthetic infection after total hip arthroplasty. METHODS: Twenty-three patients with deep periprosthetic infection treated with a standard protocol of two-staged cementless revision hip arthroplasty were enrolled in this study. There were 9 male patients and 14 female patients with an average age of 64 years (range, 52-78 years). In all cases, antibiotics-loaded cement spacers were implanted after removal of all the prosthetic components and thorough debridements had been done. All patients had a minimum of 2 weeks of intravenous antibiotics followed by 4 weeks of oral antibiotics after implant removal. After a mean interval of 6.7 months (3-28 months), revision arthroplasties were carried out with cementless femoral components followed by 2 weeks of intravenous antibiotics and 4 weeks of oral antibiotics. RESULTS: The mean follow-up period was (4.3±3.5) years. There were 2 cases of recurrent infections in this study. Intraoperative periprosthetic fractures were observed in 3 patients. One patient had dislocation of the implanted spacer during the interval period and 2 patients had hip dislocation after reimplantation. Mild subsidence of femoral component occurred in 1 patient. There were no cases of loosening of femoral components and cementless acetabular components in patients without infection recurrence. The Harris hip score increased from a preoperative mean of 36±13 to 85±13 at 12 months after reimplantation. CONCLUSIONS: Using cementless prostheses in two-staged revisions of hip periprosthetic infections can provide low rate of infection recurrence and good implant stability, but cautions must be taken when treating patients with infection caused by multidrug-resistant organisms.

Lateral patellar facetectomy had improved clinical results in patients with patellar-retaining total knee arthroplasty.

To evaluate the functional outcome of a partial lateral facetectomy in patellar-retaining total knee arthroplasty (TKA), we retrospectively analyzed 63 knees of 59 patients who underwent TKA for primary knee osteoarthritis with (32 knees of 30 patients, group 1) or without (31 knees of 29 patients, group 2) patellar facetectomy from September 2005 to July 2007. All cases were followed up for a minimum of 36 months. Although there was no significant differences between the 2 groups in preoperative patellar score, Western Ontario and McMaster Universities score, knee and function scores, postoperatively, group 1 showed more significant improvements in the scores and fewer lateral patellar osteophytes in radiographs than group 2. A partial lateral facetectomy is an effective way to improve the function of patellar-retaining TKA in patients with primary osteoarthritis.

Gait analysis of patients with metal-on-metal resurfacing hip arthroplasty compared with big-femoral-head total hip arthroplasty.

OBJECTIVE: To evaluate gait patterns in patients with metal-on-metal resurfacing hip arthroplasty (RHA) compared with big-femoral-head total hip arthroplasty (BHA) at one year postoperatively. METHODS: In this retrospective comparative observational study, 2 groups of 30 resurfacing hip arthroplasty (RHA) and big-femoral-head total hip arthroplasty (BHA) patients participated between June 2006 and March 2009 in the Sixth Affiliated People's Hospital, Shanghai Jiaotong University, Shanghai, China. Gait parameters and range of motion (ROM) in gait cycles were measured by Vicon gait analysis system and were used to calculate operated/contralateral ratios. RESULTS: No significant difference was found between gait parameter ratios, Hospital for Special Surgery Score (HSS), and University of California at Los Angeles Score (UCLA) of the 2 groups. However, there was significant difference between ROM ratios in gait cycles. Range of motions of operated hip joint were more similar to that of contra-lateral side in RHA group (hip flexion/extension p=0.007, hip abduction/adduction p=0.005, hip rotation p=0.006, knee flexion/extension p=0.037). CONCLUSION: Gait parameters of patients who underwent RHA and BHA are approaching to normal values at one year postoperatively. At the time point, ROMs of RHA patients are larger than that of BHA patients during walking.

Total knee arthroplasty using computer assisted navigation in patients with severe valgus deformity of the knee.

BACKGROUND: Severe valgus deformity often has bone defect and laxity of the medial ligamentous, and total knee arthroplasty in severe valgus knee is, in most cases, more challenging for surgeons. The usefulness of a computer assisted navigation system in reestablishing the mechanical axis has been well established. Hence, the interest for surgeons is how the navigation system makes the procedure of total knee arthroplasty with severe valgus knee easier. METHODS: From June 2006 to March 2008 in Department of Joint Surgery, Shanghai Sixth People's Hospital, 6 patients (7 knees) with severe valgus knee underwent total knee arthroplasty using the Stryker Navigation system, which is an active wireless and imageless system. All the patients were followed up for 12 to 18 months after surgery. The X-ray radiographs for whole limbs were obtained on all patients to determine preoperative and postoperative alignments. RESULTS: A primary, posterior stabilized prosthesis was utilized in all cases. The average preoperative overall mechanical axis of the seven knees was 19.6° ± 4.6° of valgus (range 16° to 29°), and the average postoperative mechanical axis was 0.4° ± 0.7° (range 0.8° varus to 1.4° valgus). CONCLUSIONS: The navigation system is a very effective and useful tool for accurate intraoperative restoration of alignment in the face of significant deformity with valgus knee. To prevent component malposition, we did not reduce the knee before solidification of bone cement but controlled alignment using the navigation system up to implantation of the final component.

[Acetabular revision with impacted irradiated frozen allografts].

OBJECTIVE: To analyze the clinical and radiographical result of acetabular revisions with wire mesh, impacted irradiated frozen allografts and cemented cups. METHODS: From February 2006 to January 2009, a total of 20 patients with 21 acetabular revisions were performed with wire mesh, impacted irradiated frozen allografts and cemented cups. Eighteen cases (19 hips) were followed up. There were 5 hips in 4 males and 14 hips in 14 females. The average age of patients was 64.4 years (43 to 81 years). Acetabular bone defects were classified according to Paprosky classification. There were Paprosky II B in 4 hips, Paprosky II C in 8 hips, Paprosky IIIA in 5 hips and Paprosky IIIB in 2 hips. Wire mesh was used to converted segmental defects into cavity defects. Irradiated frozen allografts were impacted and cemented cup was inserted to complete the revision. Patients were followed up regularly with clinical and radiographical assessment. Harris score, migration and loosening of prosthesis grafts integration and complications were observed. RESULTS: The average follow-up time was 22.4 months (12 - 48 months). Harris score improved from 42.5 points (31 - 56 points) pre-operation to 88.6 points (82 - 96 points) at the final follow up. Pain score was 14.4 point (10 - 20 point) before revision and 42.3 points (40 - 44 point) at the final follow up. COMPLICATIONS: there was 1 infection and healing after debridement. One patient had weakness of quadriceps and returned to normal after 1 year. Greater trochanter fracture occurred in 1 patient. Cup migration and loosening were observed in 1 Paprosky IIIB patients. There was no cup migration more than 1 mm or change of abduction angle in the remaining 18 hips. Grafts incorporation defined as the presence of trabecular bone crossing the graft-host bond could also be seen in these 18 hips. CONCLUSIONS: Impacted bone grafting technique combined with wire mesh and cemented cup is an effective method for biological acetabular revision. Irradiated frozen allografts implanted with impaction bone grafting technique can integrate with the surrounding host bone.

[Posterior longitudinal strip osteotomy of proximal femur in revision total hip arthroplasty].

OBJECTIVE: To evaluate the treatment and effect of a technique using single femoral posterior longitudinal strip osteotomy in revision total hip arthroplasties. METHODS: Between September 2005 and December 2009, 35 hips of 35 patients underwent a revision total hip arthroplasties (THA) in conjunction with extraction of femoral components. Among them, 23 cases were with uncemented, and 12 cases were with cemented femoral components. Those cases being followed up were chosen by two standards described as follows: one was the examination of preoperative radiographs, which showed that there was difficult in the extraction of the femoral components; Another followed was the trying with routine procedure to remove the stem. If these were unsuccessful, a single longitudinal strip osteotomy was performed, whose length was about 11 - 14 cm, and width was about 1 cm. Then the femoral component was disimpact. The osteotomy was fixed with wires or cables. If there was cortical deficiency or insufficient cancellous bone, grafting was performed. A cementless composite revision prosthesis of the Lima-Lto with a tapered modular distal fixation stem was used. All the patients were evaluated with preoperative and postoperative Harris score, the length of limb and radiographs. RESULTS: All cases were followed up with 5 to 55 months, average 15 months. Compared with preoperative, the average Harris score increased from 30 (range, 19 - 40 points) to 85 points (range, 80 - 92 points). All pains of hip joint were alleviated from the mean 12 points (range, 10 - 20 points) before the operation to 40 points (range, 30 - 44 points) after the operation. All the femoral osteotomy and bone grafting were healing ultimately. And on average, the healing began in 20 weeks (range, 10 - 32 weeks). All the cases remain the same length of lower limbs. There was no hip joint dislocation, loosening or infection. CONCLUSIONS: The femoral posterior longitudinal strip osteotomy facilitates the exposure and extraction of the femoral stem, the clear up of medullary cavity and then the femoral reconstruction in revision total hip arthroplasties. It has satisfactory short-term radiographic evaluation and clinical effect as a simple, effective and reliable technique.

Clinical application of gait analysis in hip arthroplasty.

Gait analysis technology can collect a subject's gait data when walking through motion capture systems, force plates, electromyography (EMG), and sensors. It can now be applied to a variety of medical applications. The authors review the recent advances in gait analysis technology and its current clinical application in hip arthroplasty.

[Hip resurfacing arthroplasty for secondary osteoarthritis after developmental dysplasia of hip].

OBJECTIVE: To study the clinical results of metal on metal hip resurfacing arthroplasty for developmental dysplasia patients. METHODS: From March 2005 to December 2006, 34 cases of developmental dysplasia patients (Crowe I, Crowe II) were attempted to have metal on metal hip resurfacing arthroplasty. There were 29 females (32 hips), 5 males (5 hips). The average age was 45 (26 - 57) years old. Radiographic and clinical evaluations were taken at 6 weeks, 3 months, 1 year and then once a year postoperatively. The average Harris score was 35 (25 - 44). Hip flexion was 101 degrees , abduction 24 degrees , adduction 15 degrees . RESULTS: Three patients were turned to total hip arthroplasty during operations. Thirty-one patients (34 hips) received hip resurfacing surgery. These 31 patients were followed for average 21.4 months (12 - 33 months). The average Harris score was 94 (82 - 100) at the latest follow-up, and there was statistical difference compared with the preoperative score (P < 0.01). Hip flexion increased to 133 degrees , abduction to 48 degrees , adduction to 26 degrees . No radiolucency line was found at both acetabular and femoral sides in all the patients. The average abduction angle of acetabular cup was 43 degrees (40 degrees - 53 degrees ), and the average stem shaft angle was 139 degrees (130 degrees - 145 degrees ). CONCLUSIONS: The short term result is excellent. While the mid to long term results for hip resurfacing arthroplasty in developmental dysplasia patients are still looking forward, and the meticulous surgical technique and strict patient selection are the key of the good results.

Treatment of osteonecrosis of the femoral head by percutaneous decompression and autologous bone marrow mononuclear cell infusion.

OBJECTIVE: To evaluate the clinical efficacy and safety of the treatment of osteonecrosis of the femoral head by percutaneous decompression and autologous bone marrow mononuclear cell (BMCs) infusion. METHODS: 44 hips in 28 patients with avascular necrosis at early stage were treated by percutaneous multiple holes decompression followed by autologous BMCs infusion. Autologous BMCs were concentrated from bone marrow that was taken from the posterior iliac crest of the patient. Patients were followed up at least 2 years. The results were determined by the changes in the Harris hip score and the progression in the radiograghic stages. RESULTS: No complications were observed after the operation. Before operation, there were stage I of femoral head necrosis in 8 hips, stage II in 15 hips, stage III in 14 hips, stage IV in 7 hips, and the postoperative stages at the most recent follow-up were stage O in 1 hip, stage I in 6 hips, stage II in 13 hips, stage III in 13 hips, stage IV in 7 hips, stage V in 4 hips. The mean preoperative Harris hip score was 58 (46-89), and improved to 86 (70-94) postoperatively. All the femoral head collapsed preoperatively showed that the necrotic size was at least more than 30%. CONCLUSIONS: Percutaneous multiple holes decompression combined with autologous BMCs is a new way to treat avascular necrosis of the femoral head. The earlier the stage, the better the result. A randomized prospective study needed to compare with routine core decompression in the future.