Retrograde Intramedullary Nailing for Distal Femur Fractures with Osteoporosis: An Appraisal: To the Editor

To the Editor: We read with great interest the manuscript by Kim et al. entitled “Retrograde Intramedullary Nailing for Distal Femur Fracture with Osteoporosis” in the current issue of your journal. We must congratulate the authors for this study. However, we would like to elaborate on few points and would like to draw attention of authors and readers to the following: 1. Filling void in comminuted fractures by bone cement inadvertently exposes the fracture site. Fig. 1 shows the distal femur exposed from its lateral to medial aspect. Thus, the concept of biological fixation is defeated. Submuscular bridge plating in such a scenario, allows for closed reduction of the diaphyseal/metaphyseal component of the fracture. One needs to take care of the length, alignment and rotation, and no anatomical reduction per se is required. With minimally invasive percutaneous plate osteosynthesis (MIPPO), favorable biological fixation for distal femoral fractures can be achieved, fracture haematoma is preserved and bone grafting is not required even in the case of metaphyseal communition. The authors should mention this drawback of cement augmentation and advantages of MIPPO in this subset of patients. 2. The authors did not mention the length of the nail they chose. A long retrograde nail is crucial for the stability of such fractures. In osteoporotic patients, the medullary canal tends to become very wide in the metaphyseal region which can be a risk factor for secondary displacement in varus or valgus depending on the nature of the fracture. Longer nails that achieve support in the isthmus region of the femur or incorporation of Poller screws that are close to the nail solves this problem. Longer nails provide improved initial fracture stability when compared with short retrograde nails for supracondylar femur fractures due to a more stable mechanical interaction between the femoral diaphysis and the nail. This also needs to be addressed. 3. The authors also did not mention weather they used one or two proximal locking screws, though the images (Figs. 1 and 2) show two proximal locks. A second proximal locking screw is not known to provide any additional stability; rather the presence of proximal lock below the lesser trochanter is known to lead to a stress riser. A single lock in a long nail saves surgical time and averts a stress riser and a fracture in the already osteoporotic bone. 4. The post operative treatment protocol is not clear. The authors used the statement “Weight bearing was allowed at 6th postoperative week.” Postoperative rehabilitation depends upon the stability of fixation and fracture pattern and has to be individualized for each patient. Due to expanding trumpet shape of distal femur , in case of unstable fixation, when the fracture site is subjected to stress the nail may move within the bone; therefore it is necessary to provide splint age in such situation. If the authors initiated continuous passive motion from day 1, meaning that they probably were able to attain stable fixation in all cases. If such is the case, partial weight bearing can be started immediately after surgery with ambulatory aids, though full weight bearing walking can be delayed until evidence of callus formation. The whole purpose of stable fixation is defeated if walking is delayed. The authors should explain their postoperative rehabilitation protocol more clearly. 5. Many studies have highlighted the need for dynamization after retrograde nailing. The need for dynamization of the implant to achieve fracture union has been reported to be as high as 19%. The authors remained quiet about this procedure. 6. Knee pain, though mild, is common after retrograde nailing with the incidence ranging from 13% to 60%. The authors did not make any comment about this in their series.