Yunsu Chen

Hidden blood loss after total hip arthroplasty.

A prospective study was carried out to analyze the characteristics of hidden blood loss after total hip arthroplasty (THA) in a series of 1232 patients. The method of deducting the observed perioperative blood loss from the calculated total blood loss based on hematocrit changes was used to calculate the hidden blood loss of each patient. The reinfused and transfused bloods were also considered. We found that the amount of hidden blood loss after THA was much larger than we observed perioperatively and significantly different between differently diagnosed patients. We concluded that THA can cause a large amount of hidden blood loss, which should be monitored carefully. Retaining and repairing the articular capsule is recommended during the operation, which can significantly decrease hidden blood loss.

Intraoperatively-made cement-on-cement antibiotic-loaded articulating spacer for infected total knee arthroplasty

Cement articulating spacers have been used for the treatment of TKA infection. The disadvantages of commercially available pre-made mobile spacers include limitations in implant size and antibiotic dose, often allowing delivery of only a single antibiotic agent. Hand-made mobile spacers fail to provide a well-shaped and congruently articular surface and have difficulties in maintaining stability. We present a method of intraoperatively-made cement-on-cement antibiotic-loaded articulating spacer for infected total knee arthroplasty. A custom mold was made intraoperatively with bone cement and the standard posterior stabilized TKA provisional components which were of the same size as the original prosthesis. Fabrication of the spacers did not increase the overall surgical time. From 2004 to 2007, 17 infected total knee arthroplasties were treated with two-stage reimplantation. The average length of follow-up was 31 months. One patient required an above-knee amputation for persistent infection. A knee arthrodesis was performed in one case. Ten patients received reimplantation with Nexgen LCCK knee implants. Articulating spacers were retained in situ in five patients. This articulating spacer can help improve knee mobility and function during the interval between stages.

Resurfacing arthroplasty for hip dysplasia: A prospective randomised study

In this prospective study a total of 80 consecutive Chinese patients with Crowe type I or II developmental dysplasia of the hip were randomly assigned for hip resurfacing arthroplasty (HRA) or total hip replacement (THR). Three patients assigned to HRA were converted to THR, and three HRA patients and two THR patients were lost to follow-up. This left a total of 34 patients (37 hips) who underwent HRA and 38 (39 hips) who underwent THR. The mean follow-up was 59.4 months (52 to 70) in the HRA group and 60.6 months (50 to 72) in the THR group. There was no failure of the prosthesis in either group. Flexion of the hip was significantly better after HRA, but there was no difference in the mean post-operative Harris hip scores between the groups. The mean size of the acetabular component in the HRA group was significantly larger than in the THR group (49.5 mm vs 46.1 mm, p = 0.001). There was no difference in the mean abduction angle of the acetabular component between the two groups. Although the patients in this series had risk factors for failure after HRA, such as low body weight, small femoral heads and dysplasia, the clinical results of resurfacing in those with Crowe type I or II hip dysplasia were satisfactory. Patients in the HRA group had a better range of movement, although neck-cup impingement was observed. However, more acetabular bone was sacrificed in HRA patients, and it is unclear whether this will have an adverse effect in the long term.

Tantalum implanted entangled porous titanium promotes surface osseointegration and bone ingrowth

Porous Ti is considered to be an ideal graft material in orthopaedic and dental surgeries due to its similar spatial structures and mechanical properties to cancellous bone. In this work, to overcome the bioinertia of Ti, Ta-implanted entangled porous titanium (EPT) was constructed by plasma immersion ion implantation & deposition (PIII&D) method. Ca-implanted and unimplanted EPTs were investigated as control groups. Although no difference was found in surface topography and mechanical performances, both Ca- and Ta-implanted groups had better effects in promoting MG-63 cell viability, proliferation, differentiation, and mineralization than those of unimplanted group. The expression of osteogenic-related markers examined by qRT-PCR and western blotting was upregulated in Ca- and Ta-implanted groups. Moreover, Ta-implanted EPT group could reach a higher level of these effects than that of Ca-implanted group. Enhanced osseointegration of both Ca- and Ta-implanted EPT implants was demonstrated through in vivo experiments, including micro-CT evaluation, push-out test, sequential fluorescent labeling and histological observation. However, the Ta-implanted group possessed more stable and continuous osteogenic activity. Our results suggest that Ta-implanted EPT can be developed as one of the highly efficient graft material for bone reconstruction situations.

Staged reimplantation for the treatment of fungal peri-prosthetic joint infection following primary total knee arthroplasty.

BACKGROUND Fungal peri-prosthetic joint infections (PJI) are rare complication following total knee arthroplasty (TKA). There exists no established guidelines in the treatment of these infections and controversies are focused on the usefulness of antifungal-loaded cement spacers, the duration of systemic antifungal treatment and the ideal interval between implant removal and reimplantation. Therefore we ask if: (1) adding antifungal in cement space is a viable solution to manage fungal PJI; (2) there is no adverse effect adding antifungal medication in cement? HYPOTHESIS We hypothesized that fungal PJI following TKA could be managed successfully by 2-stage reimplantation strategy using antifungal-loaded cement spacer. PATIENTS AND METHODS Five cases of fungal PJI following total knee arthroplasty were treated in our institution between 2007 and 2013 using a 2-stage reimplantation strategy. The median elapsed time from primary arthroplasty to the diagnosis of infection was 7.4 months (range, 5-10 months). The infection was caused by Candida species in 4 cases and Pichia anomala in 1 case. Antibiotic- and antifungal-loaded articulating cement spacer was implanted during the interval between stages. Systemic antifungal agents were administered for at least 6 weeks after removal of prosthesis in all cases. The mean interval between removal and reimplantation was 6 months (range, 3-9 months). RESULTS At a mean follow-up of 41.6 months (range, 24-65 months) after reimplantation, no patient had recurrent infection or revision due to any other reasons. The mean global IKS score improved from 58.4 (range, 37-96 points) preoperatively to 152.4 (range, 136-169 points) at final follow-up. The average range of motion of the knee for flexion improved from 63° (range, 10-110°) preoperatively to 98° (range, 80-120°) at final follow-up. CONCLUSIONS Fungal PJI following TKA can be successfully treated by a staged reimplantation strategy. Antibiotic- and antifungal-loaded cement spacer implanted during interval period between stages may be an effective adjunct to therapy. Effective antifungal therapy is crucial to a successful result without adverse effect. LEVEL OF EVIDENCE IV: retrospective or historical series.

Up-regulated expression of MIF by interfacial membrane fibroblasts and macrophages around aseptically loosened implants.

BACKGROUND Local chronic inflammatory reaction plays an important role in the process of aseptic loosening of implants after total joint replacement. In addition, macrophage migration inhibitory factor (MIF) is a key upstream regulator of inflammation, and it is a significant regulator of inflammatory diseases. The purpose of this study is to investigate if the fibroblasts and macrophages in the interfacial membranes overexpress MIF. MATERIALS AND METHODS The 15 tissue samples of interfacial membranes were obtained from the tissues around the aseptically loosened femoral implants adjacent to osteolytic lesion in 15 patients. The 15 control synovial samples of hip joints were obtained from 15 patients who underwent primary hip arthroplasty because of the fresh fracture of the femoral neck. The levels of MIF protein and mRNA were evaluated by ELISA assay, immunofluorescence labeling, and real-time RT-PCR. Fibroblasts and macrophages were identified by immunofluorescence labeling. RESULTS The levels of MIF protein and mRNA were significantly increased, as well as the numbers of MIF+ fibroblasts and macrophages in the interfacial membranes compared with the control synovium. CONCLUSION Not only the macrophages, but also the fibroblasts in interfacial membranes overexpress MIF. MIF may play a significant role in the process of aseptic-loosening implants after total joint replacement.

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.

Cementless total hip arthroplasty for the treatment of advanced tuberculosis of the hip.

The question of whether a total hip arthroplasty (THA) should be attempted in a patient with a current or previous tuberculosis infection continues to cause controversy. The goal of this study was to evaluate the clinical result of cementless THA for the treatment of advanced tuberculosis of the hip. Eight patients with advanced tuberculosis of the hip treated by cementless THA were retrospectively analyzed. None of the patients had draining sinus preoperatively. For patients with a confirmed preoperative diagnosis of tuberculosis and elevated C-reactive protein and erythrocyte sedimentation rate, antituberculous medication was prescribed for at least 2 weeks preoperatively. Inflamed soft tissues and destroyed bones were completely curetted out intraoperatively. All 8 patients received 1-stage cementless THA after thorough debridement. Antituberculous medications were prescribed for all patients for the first 6 months postoperatively. No patient experienced wound-healing complications. Mean Harris Hip Score was 35 (range, 30-43) preoperatively and 91 (range, 87-95) at last follow-up. At an average 46-month follow-up (range, 34-59 months), no reactivation of tuberculosis was detected. All 8 patients revealed stability by bone ingrowth on both the socket and femoral stem. Cementless THA is a safe and effective procedure for advanced tuberculosis of the hip. With thorough debridement followed by a complete course of antituberculous chemotherapy, active tuberculous infection should not be considered a contraindication for THA.

Severe Pelvic Obliquity Affects Femoral Offset in Patients with Total Hip Arthroplasty but Not Leg-Length Inequality

Leg-length inequality is an extensively studied complication of total hip arthroplasty in normal patients. However, few studies have focused on the pelvic obliquity of coronal pelvic malrotation. We hypothesized that pelvic obliquity with a fixed abduction/adduction contracture deformity of the hip may intraoperatively affect the release of soft tissues, ultimately resulting in a leg-length inequality. This study also investigated whether the femoral and vertical offsets of total hip arthroplasty were correlated with pelvic obliquity. This prospective study divided 98 patients into six groups based on the inclination of pelvic obliquity before total hip arthroplasty. Leg-length inequality, variation of pelvic obliquity, offset, and vertical offset were measured after total hip arthroplasty. Leg-length inequality and vertical offset were not significantly different among groups, whereas the variation of pelvic obliquity was significantly higher in type IIC pelvic obliquity than in other groups. Type IC pelvic obliquity had a significantly shorter offset than did the other groups, which may have been an important factor leading to type IC pelvic obliquity. Pelvic obliquity exhibited no significant effect on leg-length inequality in patients with total hip arthroplasty. A shorter offset may be caused by the higher tension of the abductor in the operated hip, which may result in the formation of type IC pelvic obliquity. Releasing the abductor contracture and restoring femoral offset are important for increasing hip stability and maintaining pelvic balance following total hip arthroplasty.

Computer-navigated TKA for the treatment of osteoarthritis associated with extra-articular femoral deformity.

The purpose of this study was to evaluate the efficacy of computed-navigated total knee arthroplasty for the treatment of osteoarthritis associated with extra-articular femoral deformity. Between January 2008 and June 2010, twelve patients (12 knees) with osteoarthritis combing extra-articular femoral deformity underwent total knee arthroplasty using the Stryker Navigation System 3.1 (Kalamazoo, Michigan), a wireless and imageless system. Average follow-up was 12.3 ± 8.2 months (range, 3-24 months). Full-length weight-bearing anteroposterior radiographs, knee range of motion, and Knee Society Score were obtained for all patients pre- and postoperatively. The data were analyzed with SPSS version 12.0 statistical software (SPSS, Inc, Chicago, Illinois). Average preoperative overall mechanical axis of the 12 knees was -10.0° ± 4.4° of varus (range, -5° to -18.5°) and average postoperative mechanical axis was -0.9° ± 0.8° (range -2° to 0°). Average Knee Society Score increased from 40.8 ± 7.7 preoperatively to 94.9 ± 2.4 postoperatively, and average function score increased from 39.6 ± 12.3 preoperatively to 95.4 ± 4.0 postoperatively. Average knee range of motion improved from 83.7° ± 18.7° preoperatively to 115.0° ± 8.2° postoperatively. The results of the study showed that computer-navigated total knee arthroplasty may be a valuable option for patients with deformed femurs in which conventional instruments are difficult to use. Follow-up observation of the long-term therapeutic effect of computer-navigated total knee arthroplasty is still needed.