[Objective]To observe the effect of bridging rabbit femoral bone defect by allograft of cortical plates.[Method]Allograft of cortical plates of frozen bone group,alcohol group and fresh group were transplated randomly into rabbit femoral bone defecs.The rabbit femoral bone defects were harvested in the 4~(th),8~(th) and 12~(th) week after the tansplantation and the biological process of allograft of cortical plates in the rabbit were analysed biomechanically,radiologically and histologically.[Result]The flexion stress and translation of the frozen group,alcohol group and fresh group were almost equal in the 4~(th) week after transplantation and there were big difference between the former two groups and fresh group.From the X-ray allograft of cortical plates were fused with host bone in the alcohol group and no fusion in the fresh group.In the 4~(th) week osteocytes were found in the frozen group and alcohol group and no in the fresh group.In the 8~(th) week the consecutive array of osteocytes were found in the frozen group and alcohol group and a little in the fresh group.In the 12~(th) week lots of consecutive array of osteocytes were found in the frozen group and alcohol group than that in the fresh group.[Conclusion]The frozen and alcohol treated and fresh allograft of cortical plates have initial biomechanical support.The allograft of cortical bone frozed group and alcohol group can fuse with host bone and that of fresh group have less ability to fuse with host bone due to immunological rejection.

Objective To determine the biomechanical variation in full-length femoral stress pat-tern and periprosthetic femoral stress distribution after implantation either with Charnley Elite cemented prostlesis or Summit proximal porous cementless femoral prosthesis. Methods Three-dimensional finite element models of intact femur, Charnley Elite and Summit femoral prostheses were developed. The stress distributions on the femur and the implants were measured. Applied with hip joint loading and related muscles strength, the stress changes of an intact femur and those implanted with either Charnley Elite or Summit protheses, especially changes in proximal femur, were respectively quantitatively analysed. Results Com-pared with intact femur, there was no change of the full-length femur stress pattern in implantation of both implants, the areas of peak values were all presented at middle and lower regions of the femur, and femoral stress value levels were decreased with both implants. Both prostheses induced significant decrease of stress in the periprosthetic bone tissue, the most serious loss of stresses all appeared at femoral calcar, the stress-shielding rates of Elite and Summit prostheses were 90.8% and 95.3% respectively. The distributions of stress shielding of both prostheses were consistent each other, the Summit proximal porous cementless pros-thesis had more serious stress decrease than the Charnley Elite cemented prosthesis. Conclusion Implan-tation of both implants may cause significant stress shielding in the proximal femur. This may be related with periprosthetic bone loss and aseptic loosening of stems, and can be used to explain the mechanism of post-operative femoral fracture and thigh pain. Both implants designs need further improvement to reduce stress changes in proximal femur.

Objective In order to probe the possible biomechanical mechanism of lumbar vertebral injuries, we studied the nonlinear stress distribution on lumbar vertebrae at 1500N axial compression force and 15Nm bending moments during hambar flexion, extension, lateral bending and axial torsion using an available nonlinear finite element (FE) model of functional spine unit. Methods Three-dimensional nonlinear FE model was created based on CT data of L3-L4 motion segment. The segment mechanical responses to different loadings were evaluated by the range of disc bulging, the stress level of fibrousrings, facet loadings and equivalent stress distribution of posterior structure. Results Compression and flexion induced disc bulging in anterior region, whereas extension and lateral bending induced disc bulging posteriorly and posterolaterally. Axial torsion caused not only higher unilateral facet stress but also the concentrated stress on posteroleteral fibrousrings stress. The loadings in extension and axial compression were lower than in torsion but higher than in lateral bending and anterior flexion. Higher equivalent stress was found when compression and extension loadings were applied to the pedicle of vertebral arch and interarticularis. Conclusion Intervertebral disc beared higher compressive than tensile. The posterolateral regions of lumbar vertebrae were prone to be deformity and at higher risk of fibrousring failure. Stress failure could be occured when facets were overloaded with axial torsion,extension and extension force due to the importance of facets during lumbar movement.

Objective To investigate the pathogenesis, clinical manifestations, imaging features, and differential diagnosis of intraosseous ganglion. Methods Clinical and imaging features of 15 cases (5 men, 10 women; mean age 39.7 years) with intraosseous ganglia were retrospectively analyzed. There were 17 lesions, including 6 acetabula, 4 lunate, 3 proximal ends of tibia, 1 major tuberculum of humeral, 1 femoral head, 1 scaphoid, and 1 phalange. Results (1) Common radiological features included a unilocular or multilocular cyst surrounded by a full and thin rim of sclerotic bone in the subchondral epiphysis without any signs of degenerative joint disease. (2) Lesions were displayed as well defined round radiolucent defect or multi cystic changes with surrounding bony sclerosis or cystic and expansile change with irregular shape on CT scans. (3) CT showed an intraosseous ganglion communicating with adjacent joint in 1 patient. (4) CT values of the lesions were between 15- 80 HU. (5) Gas in the cyst could be seen in 3 cases. Conclusion Combined with patient′s age, lesion distribution, clinical manifestations, and imaging features, it is possible to make a correct diagnosis of intraosseous ganglion.

Objective To evaluate the results of total knee replacement (TKR) in treating post traumatic degenerative arthritis. Methods A retrospective study was carried out on the results of TKR that performed in 11 patients with post traumatic degenerative arthritis due to a previous fracture around knee from 1997 to 2002. There were one female and 10 males with an average age of 59 years (31 76 years). The time from fracture to TKR averaged 8.7 years (2 27 years). Internal fixation was performed in seven cases, among which the removal of the hardware at one stage at the time of TKR was performed in four and TKR in three. Lateral retinacular release was done in four cases, extensor mechanism realignment in one and collateral ligament reconstruction in two at the time of TKR. Fracture malunion appeared in two cases during operation. Results All the cases were followed up for average 36 months (12 72 months). The mean pre operative Knee Society Scores for 37 scores (10 69 scores) for knee and 42 (0 60) for function were improved significantly to mean post operative 85 (10 100) and 75 (20 100), respectively. The mean knee arc of motion improved from pre operative 83?to post operative 93?. Post operative manipulation under anesthesia for poor motion was carried out in four knees. No knee had aseptic loosening that required subsequent revisions. One knee developed superficial infection treated with debridement and retention of components. Conclusions Significant improvement in function and relief in pain is seen in the patients with previous fractures following subsequent TKR. However, special efforts to restore limb alignment, ensure correct component position and manage soft tissue balance may improve outcome of TKA.

Objective To explore relationship between anterior knee pain after total knee arthroplasty and patella resurfacing and prosthesis design,and to evaluate which femoral prosthesis is more friendly with patella:Genesis Ⅱ or PFC knee prostheses.Methods Data of 145 patients (145 knees) who had undergone primary total knee arthroplasty for treating osteoarthritis were retrospectively analyzed.Posterior-cruciate-substituting total knee prostheses were used in all patients.Among 74 patients who had undergone patella resurfacing,Genesis Ⅱ knee prosthesis was used in 32 patients and PFC knee prosthesis in 42 patients.Among 71 patients who had not undergone patella resurfacing,Genesis Ⅱ knee prosthesis was used in 38 patients and PFC knee prosthesis in 33 patients.The Hospital for Special Surgery(HSS) score,patella score,patellar function score,range of motion of knee,anterior knee pain scale,and patient satisfaction were used to evaluate clinical outcomes.At the same time,the imaging results were evaluated by X-rays.Results 144 patients were successfully followed up for 21 to 43 months (average,33 months).There was no significant difference in incidence of anterior knee pain between the group with patella resurfacing and the group without patella resurfacing,while a significant difference was found between patients receiving Genesis Ⅱ knee prosthesis and those receiving PFC knee prosthesis.Four patients who had undergone total knee arthroplasty using PFC prosthesis underwent reoperation.There were no significant differences in postoperative HSS score,range of motion of knee and patient satisfaction between the Genesis Ⅱ group and the PFC group,while there were significant differences in patella score and patellar function score between them.Conclusion Postoperative anterior knee pain was related to the prosthesis design,rather than to the patella resurfacing.Genesis Ⅱ knee prosthesis was more friendly with patella than PFC knee prosthesis.

Objective To explore the effect and factors of patellofemoral arthroplasty (PFA) for isolated patellofemoral osteoarthritis.Methods Data of 18 patients (3 males,15 females) with isolated patellofemoral osteoarthritis underwent PFA from March 2006 to December 2014 were retrospectively analyzed.There were 3 males and 15 females with a mean age of 54 years (range,46-74 years).It was strict to grasp the surgical indications according to the clinical symptoms,signs and imaging data preoperatively.11 patients were operated with AVON patellofemoral prosthesis (Stryker Inc.) and the other 7 patients were operated with the Gender Solutions patellofemoral prosthesis (Zimmer Inc.).Active and passive functional rehabilitation exercise was encouraged at the early stage after operation.Visual analogue scale (VAS) was 5.33±0.99 (range,4-7) and hospital for special surgery knee score (HSS) was 53.28±5.71 (range,44-63) before operation.Results The mean duration of follow-up was 63.98 months (range,6-104 months).VAS after operation for 1 and 3 months were 1.17±0.79 (range,0-3) and 0.72±0.67 (range,0-2),and the pain was almost relieved after 9 months.HSS after operation for 1,3,9 months were 70.06±6.33 (range,61-80),86.06±5.12 (range,77-95) and 91.39±4.83 (range,82-97).HSS score of the latest follow-up was 92.06±4.05 (range,84-97),which was improved obviously from the preoperative ones.The excellent and good rate was 100％ (excellent 15 cases,good 3 cases).The satisfactory rate was 94.4％ (17/18).Only one case got slightly knee pain when walking up and down the stairs after 2 years,and the pain was relieved after being administered with NSAIDs and rest.No incision infection,rupture,prosthesis supported bone fracture,prosthesis loosening and other complication was occurred during the follow-up period in the other patients.Conclusion The clinical outcomes of PFA are strictly related to surgical indications,implant design and appropriate surgical technique.Therefore,based on the appropriate PFA implants,strict surgical indications,appropriate patients,excellent operation skills and actively functional rehabilitation exercise,PFA could treat the isolated patellofemoral osteoarthritis effectively.

Objective To investigate the outcomes of the treatments for the patients with Vancouver type B 1 periprosthetic femur fractures.Methods Seventeen patients with periprosthetic femoral fractures (5 males and 12 females;average age,70.4 years,range from 37 to 86 years) who underwent revision arthroplasty or open reduction and internal fixation between December 2006 and June 2016 were retrospectively reviewed.Periprosthetic femoral fractures occurred at the mean time of 65.1 months after arthroplasty.Twelve patients underwent open reduction and internal fixation and five cases underwent total hip or stem revision with Solution from Depuy,Wagner from Zimmer,Echelon from Smith & Nephew or Secur-Fit Max from Stryker due to primary bone loss,acetabular component wear or long-time prosthesis use respectively.Data were collected at 1,3,6 and 12 months and then each year postoperatively.All patients were followed up,and the results of X-ray,postoperative Harris hip score,stability of prosthesis and complications were also evaluated.Results A total of 5 patients underwent revision arthroplasty,and 12 patients underwent open reduction and internal fixation.The mean follow-up duration was 56 months (range from 7 to 120 months).Total blood loss in the open reduction and internal fixation group and in revision group was 385± 129 ml and 531± 113 ml respectively.The operation duration in the open reduction and internal fixation group was 72±36 min while it was 126±48 min in the revision group.The postoperative Harris hip score in the open reduction and internal fixation group was significantly increased compared with preoperative Harris hip score (68.8±18.4 vs.46.2±9.6),as well as in the revision group (75.0±8.9 vs.57.4±13.0).For the incidence of complications,in the open reduction and internal fixation group,one patient suffer with delayed fracture union,one patient complained about persistent pain and one suffered a secondary fracture,while in the revision group one suffered from blood loss and one with long-term pain.Conclusion Open reduction and internal fixation is an optimal intervention for Vancouver B 1 fracture,and revision arthroplasty can be considered as a safe alternative in patients with primary bone loss,implant of short survival time,severe liner wear or long-term prosthesis use.

Objective To investigate the effects of the jumbo cup in acetabular revision for patients with massive acetabular bone deficiency.Methods We retrospectively studies 48 patients (49 hips) who underwent jumbo cup revisions between 2006 and 2015 (19 men and 29 women;average age:62± 12 years).The acetabular bone defects were classified according to Paprosky classification (Paprosky Ⅱ 27 hips,Paprosky ⅢA 18 hips,Paprosky ⅢB 4 hips).Radiological assessments were conduced to evaluate the acetabular prosthesis loosening,dislocation and infection.The reasons for revisions were mechanical loosening in 41 cases,and infections in another 8 cases with cement spacer putted by last surgery.Results The operation duration and blood loss was 110 min (85-160 min) and 315 ml (270-455 ml) respectively.After an average follow-up of 6.8 years (1-11 years),Harris hip score was increased from 47.6±7.1 preoperatively to 82.4± 6.2 postoperatively.Osseointegration occurred in the acetabular components at 6 months postoperatively.Radiograph analysis showed satisfied position of acetabular cup without complications such as damages of vessels or nerves.The successful rate of jumbo cup revisions was 89.8％±4.4％.However,two in Paprosky ⅢA failures for periprosthetic infection occurred and two in Paprosky ⅢA,one in Paprosky ⅢA and the other in Paprosky ⅢB for acetabular component loosening.One patient in Paprosky ⅢB had weight-bearing pain and relieve slightly after conservative treatment.The radiologic study showed that there was no relationship between failure rate and acetabular abduction angle (r=0.06,P=0.53),rotation center migration in vertical direction (r=0.11,P=0.14) and horizontal direction (r=0.04,P=0.89).Conclusion The mid-term results show that using jumbo cup in revising acetabular failure with massive bone deficiency are optimal,which can be achieved by simplified operation procedures,reduction in the need of bone graft and promotion in acetabulum osseointegration.However,higher failure rate may occur in Paprosky ⅢB patients.

Objective To investigate the diagnostic value of knee skin temperature and serum soluble intercellular adhesion molecule-1 (sICAM-1) level in peri-prosthetic infection after total knee arthroplasty (TKA).Methods Thirty patients (11 males and 19 females,aged 59.3±9.5 years old) underwent primary TKA during November 2012 and October 2015.Ten patients with peri-prosthetic infection (3 males and 7 females,aged 60.9±8.2 years old) underwent two-stage revision TKA from November 2012 to October 2015.The interleukin-6 (IL-6),C-reactive protein (CRP),erythrocyte sedimentation rate (ESR),sICAM-1 in serum and the skin temperature in knee joint were recorded preoperatively (revision patients on diagnosis),at days 1,7 and at 1,3,6,12 months post-operatively.Results All of the 40 patients were followed up for 12 months.The serum CRP,IL-6 and ESR levels in the primary TKA group were normal preoperatively and increased after operation,reaching their peaks at 1-7 days postoperatively.These indexes then returned slowly to the normal levels within 3 months.The serum sICAM-1 level in the primary TKA group did not change significantly during the follow up.The serum levels of CRP,IL-6,ESR,and sICAM-1 in the revision group were significantly higher than that in the primary TKA group preoperatively (P＜0.05),IL-6,CRP,ESR returned slowly to the normal levels within 3 months after the second-stage revision,while the level of sICAM-1 returned to normal within 3 months after the first-stage revision.During whole follow-up after the second-stage revision,the level of sICAM-1 didn't change significantly.The preoperative mean differential temperature (MDT) in the primary TKA group was 0.73±0.62 ℃ preoperatively and elevated to 4.37±1.06 ℃ at 7 days postoperatively,which returned to the baseline within 6 months after primary TKA.The preoperative MDT in the revision group was 5.03±0.81 ℃,which was significantly higher than that in the primary TKA group (P＜0.05).The MDT returned to the normal level within 6 months after the second-stage revision TKA.Conclusion The change of MDT is in accordance with serum CRP,IL-6,and ESR,which together may predict the occurrence of infection.Serum sICAM-1 level may also be valuable in the diagnosis of peri-prosthetic infection.