Modified fixation for periprosthetic supracondylar femur fractures:Two case reports and review of the literature

BACKGROUND Periprosthetic supracondylar femoral fractures(PSFs)present a challenge in terms of optimizing fixation in patients with poor bone quality.Surgical treatment and peri-operative management of PSFs in the elderly remain a burden for orthopedic surgeons.Among different treatment options,locking plate(LP)and retrograde intramedullary nail(RIMN)have shown favorable results.However,reduced mobility and protected weight-bearing are often present in the postoperative older population.With a purpose of allowing for early weight-bearing,a modified nail plate combination(NPC)was redesigned for PSF management.CASE SUMMARY In our cases,two elderly osteoporotic female underwent total knee arthroplasty(TKA),and then suffered from low energy trauma onto their knees after falling to the floor.Plain radiographs or computed tomography scans demonstrated oblique or transverse PSFs,both of which occurred at the distal femur above TKA.The modified NPC technique was performed for treatment of PSFs.The patient was made foot flat weight bearing in 1 wk.At 6-mo follow-up,the union was ultimately achieved using modified NPC with satisfactory implant outcomes.CONCLUSION Neither LP nor RIMN alone may provide adequate support to allow for union in circumstances where the patient has severely osteopenic bone.Therefore,developing a modified implant offer an alternative choice for treating PSFs.These two cases revealed that this technique is a viable option for the geriatric osteoporotic PSFs,offering safe,early weight bearing and favorable clinical outcomes.

Rolling-element bearings in China： From ancient times to the 20th century

The development of rolling-element bearings in China has spanned a long period. Based on several typical and important cases, the present article reconstructs the history of rolling-element bearings in China by dividing it into four stages according to the various characteristics of the bearings. The first stage represents the origin of rolling beatings in China, which remains controversial because of several suspected races and cages that were likely the components of bearings more than a millennium ago. At the second stage, a type of simple roller bearing was used for astronomical instru- ments not later than the 13th century based on clear philological and physical evidence. A similar bearing was also applied to an abridged armillary in the 17th century. Another type of spherical thrust bearings with rolling elements, which is a key component of a traditional Chinese windmill, could support a rotating shaft that moves rotationally and at an angle. At the third stage, the Chinese began studying and using the so-called European- style bearing since the 17th century. Moreover, over the last 100 years, the modem rolling bearing industry was gradually established in China, particularly because of the technology transfer from the Soviet Union in the 1950s. At the fourth stage, the Chinese government initiated the relatively rapid development of beating technology. The govemment launched the ＂bearing movement＂ from the 1950s to the 1960s to establish the modem bearing industry and to promote rolling bearings as replacement for traditional sliding bearings. Furthermore, a number of large professional factories and institutions in China have continually introduced advanced technology and equip- ment. At present, these companies and institutions play a significant role in the intemational bearing industry.