Chronic knee pain following infrapatellar/suprapatellar magnetic intramedullary lengthening nails versus external fixators in limb length discrepancy: A retrospective review.

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.

Current Clubfoot Practices: POSNA Membership Survey.

Clubfoot management has advanced in the 21st century with increases in formal training, practitioner experience, and improved casting/bracing constructs. The Ponseti method is the gold standard, yet variations in application persist. This survey aims to identify current treatment practices among clubfoot practitioners within the Pediatric Orthopaedic Society of North America (POSNA). A 23-question online survey of members was conducted between June and August 2021. Eighty-nine respondents self-identified as clubfoot providers. Of these, 93.1% had an MD degree, 23.6% possessed >30 years' experience, and the majority (65.6%) worked in a teaching hospital associated with a medical school. Most responders (92.0%) were pediatric fellowship trained. A total of 51.7% had participated in a clubfoot training course. More than half (57.5%) noted changes to clubfoot management practices throughout their training. A majority used between four and seven (88.7%) long leg casts (98.4%), changed at seven-day intervals (93.4%). Plaster (69.4%) was most commonly used. The most common bracing device was Mitchell-Ponseti (72.9%). A mean 84.8% of clubfeet required tenotomy. The most common anesthetic agent was numbing gel (43.0%). Tenotomies mostly occurred in patients aged <6 months (63.1%). Tenotomy locations were operating room (46.5%), clinic (45.4%) and procedure room (8.1%). Cast removal was primarily performed with saws (54.7%). The mean incidence of observed cast burns was 5.5%. Most providers did not use a device to prevent cast burns (76.6%). Reported cast complications included slippage (85.9%), skin irritation (75.8%), and saw-related injuries (35.9%). Clubfoot management variations exist in orthotics, tenotomy indications and practices, and cast material. Casting complications continue to be a problem. Further studies are warranted to determine if certain practices predispose patients to specific complications.

Mechanical Failures in Magnetic Intramedullary Lengthening Nails.

BACKGROUND: Magnetic intramedullary lengthening nails (MILNs) have gained popularity in recent years for the treatment of limb-lengthening discrepancies. We sought to catalog mechanical failures and their prevention and management in a large, single-institution series. We specifically assessed the rate of mechanical failures, the types of failures observed, and management strategies. METHODS: We retrospectively reviewed 377 patients (420 limbs) who underwent limb lengthening with early (P1) or later (P2) MILN iterations with ≥12-month follow-up. Mechanical failure was defined as mechanical breakage of the instrumentation or nail and/or failure of the internal lengthening mechanism. Failure assessment was arranged by lengthening phases and was sorted with a complication classification system. All lengthening and alignment parameters were assessed radiographically. RESULTS: Mechanical failure was observed in 40 nails (9.5%), most of which (63%) were corrected with an additional surgical procedure. The mechanical failure rate was 11.3% in P1 nails and 9% in P2 nails. Two nails failed the intraoperative distraction test, and 1 nail was found to have a broken washer during the insertion phase. Sixteen nails had mechanical failures in the lengthening phase. Some nails (8 of 16) required nail replacement surgery. Thirteen nails failed during the consolidation phase; 7 of these cases were managed by replacement with either a functional MILN or a conventional intramedullary nail. Eight failures happened during the extraction phase and were managed intraoperatively. CONCLUSIONS: A 9.5% overall rate of mechanical failure of MILNs was observed in this large series. Resolution was achieved with an additional surgery in most cases. Nail distraction and weight-bearing compliance should be closely monitored during the lengthening and consolidation phases. Nail removal can be difficult and requires a careful study of radiographs for locking-screw bone overgrowth and backup removal equipment. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Multiplier Method for Predicting the Sitting Height Growth at Maturity: A Database Analysis.

This study aims to develop multipliers for the spine and sitting height to predict sitting height at maturity. With the aid of longitudinal and cross-sectional clinical databases, we divided the total sitting height, cervical, thoracic, and lumbar lengths at skeletal maturity by these same four factors at each age for each percentile given. A series of comparisons were then carried out between the multipliers as well as the percentiles and the varied racial and ethnic groups within them. Regarding sitting height, there was little variability and correlated with the multipliers calculated for the thoracic and lumbar spine. The multiplier method has demonstrated accuracy that is not influenced by generation, percentile, race, and ethnicity. This multiplier can be used to anticipate mature sitting height, the heights of the thoracic, cervical, and lumbar spine, as well as the lack of spinal growth after spinal fusion surgery in skeletally immature individuals.

Motorized Intramedullary Nail Lengthening in the Older Population.

Limb lengthening has not been widely employed in the elderly population due to concerns that outcomes will be inferior. The purpose of this multicenter, retrospective case-control series was to report the bone healing outcomes and complications of lower limb lengthening in older patients (≥60 years) using magnetic intramedullary lengthening nail (MILN). Our hypothesis was that healing parameters including consolidation days, the consolidation index, maturation days, and the maturation index, as well as the number of adverse events reported in the older population, would be no different to those of the general adult population. We retrospectively reviewed charts and radiographs from patients ≥60 years of age with limb-length discrepancies who underwent femoral or tibial lengthening using a MILN. Parameters were compared among the age categories "≤19 years," "20-39 years," "40-59 years," or "≥60 years" and propensity-matched cohorts for the age groups 20-59 years and ≥60 years. Complications were reported as percentages for each age category. In the study period, 354 MILN were placed in 257 patients. Sixteen nails were placed in patients 60 years of age or older (mean 65 ± 5 years; range 60-72 years). Comparisons of healing parameters showed no difference between those aged 60+ and the younger cohort. Complication percentages were not statistically significant (p = 0.816). Limb lengthening with MILN may therefore be considered a safe and feasible option for a generally healthy elderly population.

Does Focal Osteolysis in a PRECICE Stryde Intramedullary Lengthening Nail Resolve after Explantation?

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.