BACKGROUND: Total hip replacement is frequently used for osteoarthritis, rheumatoid arthritis, avascular necrosis of femoral head, et al. Although the operation is effective, some complications such as dislocation are serious and arouse more attention. OBJECTIVE: To review the research status of dislocation after total hip arthroplasty. RETRIEVAL STRATEGY: A computer-based online search of PubMed was undertaken for the English articles published between January 1997 and November 2007 with"hip replacement, dislocation". 496 related articles were collected from the above-mentioned database, including 445 original articles, and 57 review articles. Only articles ①about the influential factors for dislocation of hip joint; ②about the prevention and treatment of dislocation; ③highly correlated with the objective; and ④ published in recently or in authoritative journals were selected. Repetitive studies and Meta analyses were excluded. LITERATURE EVALUATION: Thirty-five articles were included, of which 9 were review articles and the others were clinical or empirical studies. DATA SYNTHESIS: ①Posterolateral approach in total hip arthroplasty increases the dislocation rate compared to anterior lateral approach and direct lateral approach. But when posterior articular capsule and extortor are sutured using absorbable thread before wound suture in total hip arthroplasty by posterolateral approach, the dislocation rate is increased and similar to anterior lateral approach and direct lateral approach. ②Large ball head of prosthesis can decrease the incidence of dislocation. In addition, the incidence of dislocation in prosthesis with skirted is less than prosthesis with no skirt. Elevated-rim acetabular liner can decrease but small offset distance can increase incidence of dislocation. ③Close reduction can cure early dislocation. If the dislocation is caused by infection, it is necessary to clear the wound, even take out the prosthesis for revision. Prosthesis location should be adjusted and hip joint with unbalance soft tissue should be treated by another surgery. ④If patients with recurrent dislocation, weak abductor, obvious soft tissue unbalance or other reason, it is better to use constrained prosthesis. CONCLUSION: Dislocation after total hip arthroplasty is caused by lots of complicated factors. With the acquaintance of factors and development of surgery techniques, the dislocation rate is significantly reduced than before. Complicated dislocation caused by soft tissue unbalance is the focus of future research.

Objective High tibial osteotomy was an alternative in the management of knee osteoarthritis, it could release the knee pain, correct the mechanical axis of the affected limb, and delay the total knee replacement. We were aimed at measuring the change of posterior slope angle of tibial medial plateau after high tibial osteotomy and probe its clinical consequences. Methods From 1998 to 2001, there were fifty-eight knees of 38 patients with medial unicompartmental osteoarthritis treated with closing-wedge high tibial osteotomy. The present included 8 male and 30 female patients with the average age of 55.2 years ranging 41 to 65 years. The osteotomy line was 2 cm distal to articular surfaces, and the tibia was fixed with Giebel bladed plate and two oblique long screws. The posterior slope angles of tibia and Insall-Salvati index were measured both pre and postoperatively on lateral radiographs. The posterior slope angle of proximal tibia in this study was defined as the angle between vertical line to tibial axis and the surface parallel to subchondral bone. Insall-Salvati index was defined as the ratio of the length of patellar tendon to the largest vertical diameter of patella. The alteration of the above features was calculated and analyzed statistically with paired t test. Results The mean tibial posterior slope angle was 9.4??3.0? preoperatively and 5.6??2.6?postoperatively. The tibial posterior slope angle was averagely decreased about 3.8??2.0?, Insall-Salvati index was 1.05?0.16 and 0.94?0.18 before and after high tibial osteotomy respectively. This index was averagely decreased about 0.15?0.10. Statistical analysis indicated that there was significant difference of posterior slope angle or Insall-Salvati index between pre and post operative(P

Objective To investigate the preliminary results of total ankle replacement with a three components of mobile bearing scandinavian total ankle replacement(STAR). Methods From October 1999 to February 2003, 13 cases of total ankle replacement were performed with STAR system (Waldemar Link, Hamburg, Germany). There were 8 males and 5 females with an average age of 63.4 years (range, 58 to 69 years). The diagnoses were posttraumatic arthritis in 6, osteoarthritis in 3, Kaschin-Beck disease in 2 and rheumatoid arthritis in 2. An anteromedial curve incision extended distally and proximally from the center of ankle joint. After the exposure and osteotomy, the uncemented tibial and talar components were implanted, a suitable sliding nucleus should be checked in order to keep the soft tissue balance. One total ankle arthroplasty was converted to ankle arthrodesis because of fracture of lateral malleolus occurred during operation. Results Among 12 total ankle arthroplasties, 8 had detailed follow-up data. The average period of follow-up was 16 months (range, 6 to 38 months). All the followed-up ankles were scored with Kofoed total ankle scoring system. The average preoperative and postoperative ankle score were 29 (6-49) and 82 (56-99) respectively. None of prosthetic loosening and migration was found radiologically. However, one case of delayed wound healing treated with dressing change for 4 weeks. One case of fractured medial malleolus was internally fixed with K wire, and the stability of tibial component was not compromised. Conclusion With current ankle arthroplasty designs, total ankle replacement is a viable treatment for symptomatic ankle arthritis that has no responses to nonoperative treatment. Although the preliminary results of total ankle arthroplasty are encouraging, there is still need for careful, long term analysis to estimate to what extent current ankle arthroplasty can relieve pain and restore ankle function. Further attention must be paid to more accurate implantation techniques that will result in a well balanced ligament and allow the ligament to act together with the replaced surfaces in a most physiologic manner.

Objective To evaluate the short-term results of total metatarsophalangeal arthroplasty (TMPA) for OA, RA, hallux valgus with severe OA, hallux rigidus, and osteonecrosis of metatarsal heads. Methods From March 2002 to March 2005, total metatarsophalangeal arthroplasty was performed in 30 patients (11 males and 19 females, age from 33 to 77 years old, average 62.5 years old) and 47 feet. Fifteen were bilateral. The preoperative underlying diagnosis was RA in 7, hallux rigidus in 5, hallux valgus with severe OA in 21, avascular osteonecrosis in second metatarsal head in 6, old metatarsophalangeal dislocation in 2, complications after McBride operation in 2 feet. Totally, 33 first metatarsoplangeal joints, 11 second metatarsophalangeal joints, 2 third metatarsophalangeal joints and 1 fourth metatarsophalangeal joint were replaced with metal bushed silicon Swanson prostheses. Two patients (4 feet) with abnormal first-second intermetetarsal angle (19?-20?) received simultaneous proximal metatarsal osteotomy. The osteotomed metatarsal were fixed with Biofix absorbable screws. Two patients (3 feet) received simultaneous metatarsal head (2-5) resection arthroplasty. Twenty-nine (46 feet) were followed-up for average 26.5 (3-36) months with Maryland metatarsal joint scoring system. Oriented by the Maryland scoring system, pain, joint function, and objective messurements were recorded and scored. Results The preoperative and postoperatvie Maryland score was 72 (55-82) and 91 (67-96), respectively. Excellent result was achieved in 41 feet (89.13%), good in 2 feet(4.35%), fair in 2 feet(4.35%), and poor in 1 foot(2.17%). The good-excellent result rate in this group was 93.48%. The complications included: delayed wound union in 2 feet, implant dislocation in 1 foot, reactive synovitis in 1 foot. Conclusion The short-term result of total metatarsophalangeal arthroplasty for treatment of OA, RA, hallux rigidus, old dislocation of metatarsophalangeal and avascular osteonecrosis of metatarsal heads is satisfying.

Objective To investigate the medial-lateral tilting of patella in two different coordinate systems before and after total knee arthroplasty (TKA). Methods Six fresh-frozen left low limbs from cadaver were tested using a modified Oxford Rig. Anatomically based multiple loading of the quadriceps mechanism was applied(Vastus medialis 24.5 N, Vastus intermedius/rectus femoris 29.4 N, Vastus lateralis 19.6 N). In a three dimensional coordinate system, patellar tilting was tracked using a custom-made Laser tracking device. The femoral trochlea was used as the other coodinate system in skyline view of patellar-femoral joint. Total knee arthroplasty was performed using PFC? posterior cruciate ligament substituting knee system. The tilting angles of patellar were measured before and after TKA. Results In three dimensional coordinate system, when knee flexed 30?,60?,90?,120?,150?, the patella titled :-3.10??2.25?,2.50??1.07?,5.46??2.60?,6.32??2.16?,-2.10??1.90? respectively before total knee arthroplasty was undertaken. After total knee arthroplasty, the patella tilted 3.24??0.35?,2.30??1.39?,1.65??1.17?,1.29??1.03?,-0.86??1.42? respectively. When femoral trochlea was taken as coordinate, the patella tilted 0??0?,0??0?,0??0?,0.24??0.35?,-3.21??1.80?; 0??0?,0??0?,0??0?,0??0?,-1.12??1.20? respectively both before and after TKA (Lateral patella tilting was defined as positive and medial patella tilting, negative). Conclusion Even the relationship between patella and femoral trochlea remains normal, the mode and magnitude of patellar tilting changes significantly after TKA. In early flexion of knee joint, patella tilts medially before TKA while it tilts laterally after TKA. After TKA, patella tilts less laterally than it does before TKA when a knee flexes from 60 to 120 degrees.

[Objective]To measure the change of anatomic configuration of proximal tibial after high tibial osteotomy and probe its clinical consequences.[Method]From 2001 to 2005,there were 59 knees of 35 patients with medial unicompartmental osteoarthritis treated with closing-wedge high tibial osteotomy.Anatomic configuration of proximal tibia were measured both pre and postoperatively on radiographs.They included posterior slope angle of proximal tibia,tibial angle,lateral shift of articular surface of proximal tibial and level of the joint line.The alteration of the above features was calculated and analyzed statistically with paired t test.[Result]The mean tibial posterior slope angle were(8.9??2.6?)preoperatively and(5.0??2.3?)postoperatively.The tibial posterior slope angle was averagely decreased about(3.9??1.7?).Tibial angle were(99.1??4.3?)and(91.1??3.8?)before and after high tibial osteotomy respectively.Lateral shift of articular surface of proximal tibial were(46.2?3.6)% and(53.1?3.9)% in pre and postopratively.Level of joint line was(41.2?3.6)mm and(38.0?3.2)mm in pre and postopratively.Statistical analysis indicated that there was significant difference of posterior slope angle or tibial angle or lateral shift of articular surface of proximal tibial or level of joint line between pre and post operative(P

[Objective] To study the application and clinical result of extended trochanteric osteotomy in hip joint revision.[Methods]Thirteen hips in 13 patients who were treated with extended trochanteric osteotomy in hip joint revision from 2003 to 2007 were followed-up for an average time of 32.3 months.The revision reasons,Harris score,osteotomed length,and the oeteotomed union time were analyzed.[Results]The average preoperative Harris score of all patients was 38(24~68),the average postoperative Harris score was 77(57-100),with the improvement of 39 points.The average osteotomed length from the tip of great trochanter to distal osteotomy site was 12.4 cm(9~15.1 cm).The osteotomy sites were healed in 11 patients at 3 months and 2 patients at 6 months after operation.[Conclusion]Extended trochanteric osteotomy is useful in hip joint revision.After osteotomy femoral prosthesis and cement could be taken out easily,and the osteotomy site could be healed easily.

Objective To investigate the effect of femoral design on anterior knee pain after patella reserving total knee arthroplasty. Methods From 15 January to 15 February 2002, 44 patients and 59 knees were followed up. Among these patients, 40 patients and 51 knees were included in this study, the rest cases were excluded for one or more of following factors. 1)Knee flexion was less than 80 degrees;2)Radiography showed that there were surgical errors such as: femoral component flexion more than 30, anterior femoral cortex notching, and patellar baja or alta. According to current generally accepted criteria, femoral components were classified as "Patella Friendly" group and "Patella Unfriendly" group. The percentage and severity of anterior knee pain was measured with patient visual pain index and Knee Society Functional Score System. Results The aforementioned two groups consisted of "Patella Friendly" group 21 knees and "Patella Unfriendly" group 31 knees. The average anterior knee pain score of "Patella Friendly" group and "Patella Unfriendly" group was respectively 1.58 (0-8) and 3.32 (0-6). The percentage of pain free patients of the two groups was 64% and 9%. There was significant statistical difference between the groups in terms of anterior knee pain score (t=4.642, P

Objective To investigate the coupling of tibial rotation and extension-flexion motion of knee joint both before and after total knee arthroplasty. Methods Six fresh-frozen left lower limbs from cadavers were tested using a modified Oxford motor rig for the knee joint. Anatomically based multiple loadings of the quadriceps mechanism were applied (Vastus medialis: 24.5 N, Vastus intermedius/rectus femoris: 29.4 N, Vastus lateralis: 19.6 N). The tibial rotation was tracked using a custom-made laser tracking device while the tibial-femoral flexion was measured with goniometer. Total knee arthroplasty (TKA) was performed using ?PFC-PS posterior cruciate ligament substituting knee system. Results Before TKA, when the knee flexed 10?, 20?, 30?, 60?, 90?, 120? and 150?, tibia rotated 5.1??2.3?, 9.3??3.3?, 10.2??4.8?,11.7??3.5?, 13.5??8.4?, 22.0??8.6? and 29.6??9.3? respectively. After TKA, tibia rotated -2.2??1.7?, -2.5??1.5?, -2.0??1.3?, 1.7??2.5?, 3.9??2.4?, 13.5??6.1? and 18.6??4.7? respectively (Tibial rotation was defined as 0? in knee extension; internal rotation as positive and external rotation as negative). Conclusion The tibial internal rotation is coincident with tibial-femoral flexion, its magnitude of tibial rotation varies in different degrees of knee flexion. The tibial internal rotatation is significant in early knee flexion(0? to 30?), then enters into a platform stage on knee bending from 30? to 90?, Once the knee bends over 90?, the tibia rotates internally markedly again, maximum internal rotation is achieved in fully flexion, probably due to relaxation of soft tissue. After TKA, in early flexion (0? to 30?) the external rotation occurs abnormally, but later on 30? to 150?, it rotates again intenally as normal.

O bjective To introducetheosteotomyofacetabularmedialwallas a techniqueto facilitateanatomicalimplantationand securefitofacetabularcupsfordysplastichips. Methods Eighteen hipreplacementswereperformedwithuseofan osteotomyofacetabularmedialwalltostabilizethecups in 17 dysplasticpatients. The patientswere aged from35-70 years, withan averageof51.4 year. Among all thedysplastichips,4 were oftypeⅠ,7 oftypeⅡ,4 oftypeⅢ,and 3 oftypeⅣ accordingtotheCrowe criteria. A Ranawat trianglewas drawn on theX-ray film, and a supposedoptimalrotatingcenterwas located.Bothofthehorizontaland verticaldistancesbetweenfemoralhead and supposedrotatingcenterwas decreasedsignificantlyafteroperation.Results With medialwallosteotomy,alltheacetabularcomponents wereplacedinthetrueacetabulum.The diametersoftheimplantedcupswere44-56 mm withan averageof 50.78 mm . Medialbony wallwas preservedwithan averagethicknessof9.5 mm . The horizontaldistance was 21.09 mm (12-40 mm )preoperativelyand 3.73 mm (-3-10.1 mm )postoperatively,therewas statistical difference(t=7.95,P