Fragomen Austin T, Rozbruch S Robert
Limb Lengthening and Complex Reconstruction Service, Hospital for Special Surgery, Weill Medical College of Cornell University, New York, NY.
JBJS Essent Surg Tech. 2016 May 11;6(2):e20. doi: 10.2106/JBJS.ST.15.00069. eCollection 2016 Jun 22.
Femoral lengthening with an intramedullary nail inserted through a retrograde approach offers the unique benefit of accurate deformity correction and distraction osteogenesis without the need for external fixation with its inherent challenges.
STEP 1 PLANNING THE DEFORMITY CORRECTION AND NAIL INSERTION: The key to a successful deformity correction and proper nail placement is preoperative planning.
STEP 2 INSERT THE ROTATION MARKER PINS AND BLOCKING SCREWS: Insert 2 Steinmann pins or half-pins into the proximal and distal aspects of the femur to mark any rotational deformity that is being corrected or to ensure that no rotational deformity is created. The Steinmann pins need to be ≥3 mm in diameter to prevent bending with loss of rotational reference. We prefer 5-mm or 6-mm Schanz pins for this role. These sturdy pins may be used as a "joystick" for manipulating the distal fragment to achieve a correction.
STEP 3 PREPARE THE DISTAL FRAGMENT: This step includes the approach to and reaming of the distal fragment, which is critical to the limb alignment.
STEP 4 OSTEOTOMY: Perform the percutaneous osteotomy, which allows for correction of the deformity, prior to reaming the proximal segment.
STEP 5 PREPARE THE PROXIMAL FRAGMENT: While holding the distal fragment in the reduced position, prepare the proximal fragment for nail insertion.
STEP 6 NAIL INSERTION: Insert the nail in a standard fashion, avoiding excessive force that could damage it or jam it into the proximal fragment.
STEP 7 LOCK THE NAIL: Lock the nail from the distal or proximal end first. The femoral distractor helps to keep the rotation accurate during locking and helps to serve as a handle to obtain perfect overlapping circles of the locking screw site on fluoroscopy. However, the external fixator may be obstructive for distal locking in particular. The fixator can be removed for distal locking and reattached for proximal locking.
STEP 8 FINAL BLOCKING SCREWS: Check the anteroposterior and lateral fluoroscopic images and decide how stable the nail is in the bone. Will the fragment shift into varus, valgus, or flexion?
STEP 9 MARK THE MAGNET AND TEST THE NAIL: Mark the position and orientation of the magnet in the nail on the patient's skin to indicate where to place the external magnet for lengthening.
STEP 10 POSTOPERATIVE CARE AND LENGTHENING: Postoperative management involves nail distraction, venous thromboembolic (VTE) prophylaxis, and adherence to a specific weight-bearing protocol.
Femoral lengthening with the remote-controlled magnetic intramedullary nail has had excellent clinical efficacy.
通过逆行入路插入髓内钉进行股骨延长具有独特的优势，即能精确矫正畸形并进行牵张成骨，而无需面对外固定带来的固有挑战。
步骤1 规划畸形矫正和髓内钉插入：成功矫正畸形和正确置入髓内钉的关键在于术前规划。
步骤2 插入旋转标记针和阻挡螺钉：在股骨近端和远端各插入2根斯氏针或半针，以标记正在矫正的任何旋转畸形，或确保不产生旋转畸形。斯氏针直径需≥3毫米，以防止弯曲导致旋转参考丢失。我们更倾向使用5毫米或6毫米的斯氏针来完成此操作。这些坚固的针可作为“操纵杆”来操作远端骨折块以实现矫正。
步骤3 准备远端骨折块：此步骤包括对远端骨折块的入路和扩髓，这对肢体对线至关重要。
步骤4 截骨：在扩髓近端节段之前，进行经皮截骨，以矫正畸形。
步骤5 准备近端骨折块：在将远端骨折块维持在复位位置的同时，准备近端骨折块以插入髓内钉。
步骤6 插入髓内钉：以标准方式插入髓内钉，避免用力过度而损坏髓内钉或将其卡在近端骨折块中。
步骤7 锁定髓内钉：首先从远端或近端锁定髓内钉。股骨撑开器有助于在锁定过程中保持旋转精确，并有助于作为手柄，以便在透视下获得锁定螺钉部位完美重叠的圆圈。然而，外固定器尤其可能妨碍远端锁定。可拆除固定器进行远端锁定，然后重新安装以进行近端锁定。
步骤8 最终阻挡螺钉：检查前后位和侧位透视图像，确定髓内钉在骨内的稳定性。骨折块会向内翻、外翻还是屈曲移位？
步骤9 标记磁铁并测试髓内钉：在患者皮肤上标记髓内钉中磁铁的位置和方向，以指示在延长时外部磁铁的放置位置。
步骤10 术后护理和延长：术后管理包括髓内钉撑开、预防静脉血栓栓塞（VTE）以及遵守特定的负重方案。
使用遥控磁性髓内钉进行股骨延长具有出色的临床疗效。
