RESUMO
Aims & objectives: Prior to the popularization of magnetic intramedullary nails (MILNs), gradual deformity correction using external fixation was the norm in limb lengthening. Trauma literature has shown MILN via a suprapatellar approach (SP) to be associated with less knee pain than either an infrapatellar entry (IP) or external fixation. Yet, no research has investigated chronic knee pain and MILNs. We assessed differences in chronic knee pain following lengthening via an IP or SP approach with an MILN versus external fixation. Materials & methods: We reviewed 147 limbs (55 MILN/IP, 22 MILN/SP, 71 external fixator) in 124 patients who underwent tibial lengthening with ≥12 months follow-up between February 2012 and July 2020. Knee pain was assessed pre- and postoperatively at 6 and 12 months, with the Lysholm Knee Scoring Scale (LKSS) and numeric pain scale (0-10). Differences in knee pain outcomes were compared across methods, with subgroup analysis of MILN/SP and MILN/IP. Results: Mean LKSS was 96.3 for external fixation and 88.5 for MILN (P = .011). In the MILN subgroups, mean LKSS was 91.7 for IP and 85.3 for SP. The IP group reported a lesser mean pain score (0.6 versus 2.1) at 12 months. Bilateral nail recipients demonstrated no knee pain differences versus unilateral. At 12 months postoperative, external fixation had better knee outcomes. Conclusion: Tibial lengthening with external fixation was associated with less chronic anterior knee pain and better functional outcomes than MILN overall. In terms of MILN approach, IP surpassed SP on subjective pain scores. Larger tibial lengthening and knee pain studies are warranted.
RESUMO
Concerns surrounding osteolysis near and around the modular junction of a stainless-steel intramedullary lengthening rod prompted a manufacturer recall from the United States market in early 2021. These actions were preceded by similar steps taken in Europe. A concomitant review of stainless-steel lengthenings at our institution demonstrated signs of adverse tissue reaction including periosteal reaction and osteolysis at the modular junction and/or male-sided locking screws. Nearly half of our patients presented with these findings on radiographic images. At the time of the previous review, only half of the nearly 60 implanted stainless-steel devices met a 6-month follow-up. At this juncture, many patients have had their devices explanted. Given the suspected adverse tissue reactions caused by a component of the internal device, we sought to examine the rate of osteolysis post-explantation following removal of a stainless-steel nail. We reviewed a consecutive series of patients who underwent implantation of a stainless-steel limb lengthening device in the femur and/or tibia at a single institution between December 2018 and December 2020. Patients were included if their device was explanted. Periosteal reaction and osteolysis was classified according to a novel and validated classification system, as analyzed by five fellowship-trained surgeons. In addition, changes observed prior to explantation were tracked post-explantation to assess for resolution. The incidence of periosteal reaction and osteolysis prior to explantation was 22/57 (39%) and 15/57 (26%), respectively. Of the 15 patients with osteolysis pre-explantation, 14 patients' implants were explanted. Of these, eight patients had available follow-up films. Two patients were identified as having partial osteolysis resolution at mean 1-year follow-up, while six patients were identified as having complete osteolysis at mean 18-months follow-up. Periosteal tissue reaction and osteolysis largely resolved following explantation in a subset of patients. These results provide further support to the claim that the stainless-steel device contributed to the changes seen. Further follow-up is warranted to examine the longer-term effects of adverse tissue reaction in this patient population.