Abstract The fracture of the prosthetic stem after prosthetic replacement of femoral head is not rare. In this study, the photoeastic instrument was used to study the stress distribution on the prosthetic stem following its insertion and to analyse the factors influencing the fracture of the stem. Through the examination of 9 places in 8 cases, it was found that:(1) The removal of femoral calcar and the inframedullary filling of the bone cement directly influenced the stress distribution. (2) The valgus or varus condition of the prosthesis would lead to stress concentration on the stem. (3) Once lossening of the prosthesis occured it would change the preliminary installingstress distribution in the upper femur which would lead to fatigue fracture. Ths experimental data and clinical observation would provide scientific basis forthe prevention of fracture of prosthetic stem following prosthetic replacement of femoral head.
Objective To study the operative effect and complication of the prosthesis replacement of the proximal humerus with malignant tumor. Methods From October 1998 to August 2003, the prosthesis replacement was performed to treat the proximal femur with malignant tumor in 4 patients, including 2 patients with osteosarcoma (Enneking staging,ⅡA) and 2 patients with giancell tumor of the bone (ⅡA,ⅡB). By the International Society of Limb Salvage(ISOLS) criterion, the 2 cases of osteosarcoma were preoperatively scored as 4 and 5 points, and 2 cases of giant cell tumor of the bone were scored as 9 and 11 points. The patients’ psychological conditions as well as their limb pain, shape, locality, activity, and function werealso observed. Results The follow-up for 24-58 months (mean, 44 months) showed that there was no local recurrence or infection in all the patients except onepatient who had the loosening of the screws for the fixation 17 months after operation and had no treatment. After operation, all the patients had a better postoperative extention angle from 22° to 41°(mean, 25°), bending angle from 29° to 80°（mean, 35°）, abduction angle from 5° to 28°, and circumgyrate angle from 15° to 22° in their shoulder joints. However, the shoulder joint function was still unstable to some extent and the joints had a decreased strength. By the criterion formulated by the ISOLS, the postoperative score for assessing the 2 patientswith osteosarcoma was increased by 16 points when compared with the preoperative score; the score for the 2 patients with giant cell tumor of the bone was increased by 9.5 points.Conclusion The prosthesis replacement to treat the malignant tumor of the proximal humerus is the good method of choice and has a good therapeutic result; however, there are more complications and so the method should be cautiously employed in the clinical practice.
Objective To introduce the occurrence mechanisms, prevention, and treatment measures of prosthetic aseptic loosening. Methods The recent original articles about prosthetic aseptic loosening were extensively reviewed and analyzed. Results Prosthetic aseptic loosening was a very complex process involving many mechanical and biological aspects. The main mechanical factors included prosthetic materials, shapes and sizes, implant fixation methods (including surfacetreatments), cl inical installation, interface micromotion, stress shielding, implant wear, interface integrity, and peri prosthetic high hydraulic pressure, etc.; the main biological factors included the types and sizes of wear particles, cell-activated responses, cytokine release, enzyme activation and allergic reactions to wear particles, etc.. Many measures should be adopted to effectively prevent and treat it, including improving materials and designs of prostheses, fixation techniques, surgical techniques, and drug treatments. Conclusion Prosthetic aseptic loosening is still a troublesome compl ication after joint replacements in orthopaedics, and more attention should be paid for its effective prevention and treatment.
Objective To study the clinical feasibility of the prosthetic composites of the intercalary allograft and the segmental allograft in reconstruction of the skeletal defect after the limb tumor resection. Methods Between August 1999 and December 2003, 28 patients with skeletal defects after the limb tumor resection were treated with the intercalary allograft or the segmental allograft megaprosthesis composite for reconstruction of skeletal defects. The bone involvements were observed in 16 patients with osteosarcoma, 4 patients with parosteal osteosarcoma, 5 patients with Ewing sarcoma, and 3 patients with soft tissuesarcoma. Preoperative biopsy was performed on all the patients, and the pathological result was confirmed after surgery. According to the Enneking system, 5 patients were grouped in ⅠB and 23 patients in ⅡB. The patients with osteosarcomaor Ewing sarcoma received the standard chemotherapy before and after operation.Eighteen and ten patients received the segmental allograft prosthetic compositereplacement and the intercalary allograft with the interlocking intramedullary nail fixation, respectively. The functional outcome was evaluated by the MSTS score. Results According to the follow-up for 5-48 months (average, 24 months), local recurrence was observed in 1 patient who underwent amputation eventually. Of the 28 patients, 3 developed nonunion of the allografthost junction accompanied by severe resorption and 2 developed deep infection. No allograft fracture was seen in the patients. Most of the patients achieved a good functional result with an average MSTS score of 23.4. ConclusionThe prosthetic composite replacement of the intercalary allograft and the segamental allograft can be used n the skeletal defect reconstruction after the limb tumor resection. The stablecontact in the allografthost junction and the b intramedullary internal fixation can help to reduce the complication rate of the allograft.
Objective To study the effect of all-coated long stem prosthesis associated with allograft in revision total hip replacement (THR). Methods From January 1997 to January 2004, 20 patients with non-infectious loosened implant after primary THR were treated. There were 12 males and 8 females with a mean age of 65 years (58-77 years). The average period between primary THR and revision THR was 12 years (3-18 years). According to classification of Paprosky, there were10 cases of type II, 6 cases of type IIIA, 3 cases of type IIIB and 1 case of type IV. All-coated long stem prosthesis was used in all cases. Impacting bone grafting was done in 12 cases and impacting bone grafting associated with cortical strut grafting in 8 cases. The mean amount of morsel ized bone was 20 g (5-35 g), the length of cortical bone was 10-22 cm. Results All the incisions got heal ing by first intension. All patients were followed up for an average period of 36 months (16-48 months). Dislocation occurred at 5 days after operation and was cured with closed reduction and traction in 1 case. There was significant difference (P lt; 0.05) in the mean Harris score between preoperation (50.0 ± 2.3) and postoperation (90.0 ± 2.5). The X-ray checking showed that continuous radiolucent l ine of 3 mm occurred in 1 case, prosthesis subsidence of 5 mm and 7 mm in 2 cases and that no bone absorption was observed. Seven cases of cortical bone grafting union was achieved within 3 years except 1 case of cortical bone un-union. Conclusion It can obtained the initial stabil ization of prosthesis to use all-coated long stem prosthesis associated with allograft in revision THR to treat femur bone defect after THR. The short-term effects of the cl inical and X-ray checking are satisfactory, but future effect is to be observed.
ObjectiveTo review the current development in therapy of congenital funnel chest. MethodsRecent literature concerning the development of the treatment method for congenital funnel chest was extensively reviewed and summarized. ResultsThe main therapies for congenital funnel chest are thoracoplasty (Ravitch sternum elevation procedure and minimal invasive Nuss procedure) and prosthesis implantation. The magnetic mini-mover procedure and the vacuum bell are still in the research phase. ConclusionBesides the improvement in function, the requirement in appearance after surgery is also improved in the treatment of congenital funnel chest. The minimally invasive surgery and non-invasive procedures could be expected in the future.
In unicompartmental replacement surgery, there are a wide variety of commercially available unicompartmental prostheses, and the consistency of the contact surface between the common liner and the femoral prosthesis could impact the stress distribution in the knee after replacement in different ways. Medial tibial plateau fracture and liner dislocation are two common forms of failure after unicompartmental replacement. One of the reasons is the mismatch in the mounting position of the unicompartmental prosthesis in the knee joint, which may lead to failure. Therefore, this paper focuses on the influence of the shape of the contact surface between the liner and the femoral prosthesis and the mounting position of the unicompartmental prosthesis on the stress distribution in the knee joint after replacement. Firstly, a finite element model of the normal human knee joint was established, and the validity of the model was verified by both stress and displacement. Secondly, two different shapes of padded knee prosthesis models (type A and type B) were developed to simulate and analyze the stress distribution in the knee joint under single-leg stance with five internal or external rotation mounting positions of the two pads. The results showed that under a 1 kN axial load, the peak contact pressure of the liner, the peak ACL equivalent force, and the peak contact pressure of the lateral meniscus were smaller for type A than for type B. The liner displacement, peak contact pressure of the liner, peak tibial equivalent force, and peak ACL equivalent force were the smallest for type A at 3° of internal rotation in all five internal or external rotation mounting positions. For unicompartmental replacement, it is recommended that the choice of type A or type B liner for prosthetic internal rotation up to 6° should be combined with other factors of the patient for comprehensive analysis. In conclusion, the results of this paper may reduce the risk of liner dislocation and medial tibial plateau fracture after unicompartmental replacement, providing a biomechanical reference for unicompartmental prosthesis design.
Objective To evaluate the clinical effect of Easy Prosthesis D-10 on open preperitoneal groin tension-free hernioplasty. Methods The operative time, operation-correlated complications, hospital stay and recent follow-up findings of 63 patients underwent preperitoneal groin tension-free hernioplasty were analyzed from October 2006 to April 2008. Results No case died in perioperative period. The average operative time was (47.6±10.5) minutes. None of incision infection and scrotal hydrocele occurred. The average hospital stay was (7.7±2.1) days. During follow-up period of 6 to 24 months, no recurrence, chronic pain and foreign body sensation were found. Conclusion The open preperioneal groin tension-free hernioplasty by Easy Prosthesis D-10 is safe and reliable, especially for the inguinal hernia with large hernia ring or defect of transversalis fascia and recurrent hernia.
After freatment of prosthesis replacement for 12 malignant tumer of the proximal humoral werereported. The operation were performed after the indications and methods of treatment had beendefined. All of the 12 cases were followed-up, in the average of 8 yeare. On functional evaluation , 8cases had satisfactory result , but per in 1 cases and 3 cases died from recurrence or metastasis withinfive years. The indieation of the procthetic replantation, the complications, and revision weredisecused.
ObjectiveTo investigate the effect of preoperative valgus or varus deformity on the prosthesis installation and alignment restoration in total knee arthroplasty (TKA). MethodsBetween January 2012 and December 2013, 198 patients (245 knees) with osteoarthritis underwent primary TKA, and the clinical data were retrospectively analyzed. There were 23 males and 175 females, with the average age of 67 years (range, 43-90 years). Single knee and double knees were involved in 151 and 47 cases respectively. The disease duration was from 1 month to 30 years (mean, 8.99 years). The anteroposterior X-ray films of whole lower limbs were taken, and the femorotibial angle (FT) was measured before operation and at 1 week after operation; the mechanical femoral angle (MF) and the anatomical tibial angle (AT) at 1 week after operation were measured. The correlation analysis was made for pre-and post-operative FT, MF, and AT. According to the valgus or varus deformity before operation, all patients were divided into 5 groups:≥20° varus (group A), 10-20° varus (group B), ≤10° varus (group C), < 10° valgus (group D), and≥10° valgus (group E), and the above indicators were compared between groups. And the rate of the good limb alignment was recorded after operation. ResultsThe pre-and post-operative FT were (171.53±9.12) and (177.38±3.57)° respectively, and postoperative MF and AT were (89.00±2.68) and (88.62±2.16)° respectively. Preoperative FT was associated with postoperative FT and MF (r=0.375, P=0.000; r=0.386, P=0.000), but it was not correlated with AT (r=0.024, P=0.710). Postoperative FT was associated with MF and AT (r=0.707, P=0.000; r=0.582, P=0.000). Postoperative FT was significantly increased when compared with preoperative FT in each group (P < 0.05). There were significant differences in preoperative FT between groups (P < 0.05). There were significant differences in postoperative FT when compared group A with groups B, C, D, and E (P < 0.05), and when compared groups B and C with groups D and E (P < 0.05), but there was no significant difference between groups B and C, and between groups D and E (P>0.05). The rate of good alignment was 70.2% (172/245); it was 27.8% (5/18), 66.0% (62/94), 74.4% (67/90), 88.9% (32/36), and 85.7% (6/7) in groups A, B, C, D, and E respectively, showing significant differences between groups (P < 0.05). There was no significant difference in postoperative AT between groups (P>0.05). Except for between group D and group E (P>0.05), significant difference in MF was shown between the other groups (P < 0.05). ConclusionThe more severe deformity of lower limb before TKA, the higher risk of deviation for prosthesis installation and poor alignment in TKA.