ABSTRACT
BACKGROUND: Magnetic intramedullary lengthening nailing has demonstrated benefits over external fixation devices for femoral bone lengthening. These include avoiding uncomfortable external fixation and associated pin site infections, scarring, and inhibition of muscle or joint function. Despite this, little has changed in the field of biologically enhanced bone regeneration. Venting the femoral intramedullary canal at the osteotomy site before reaming creates egress for bone marrow during reaming. The reamings that are extruded from vent holes may function as a prepositioned bone graft at the distraction gap. The relationship between venting and the consolidation of regenerating bone remains unclear. QUESTIONS/PURPOSES: (1) Do bone marrow reamings extruded through venting holes enhance the quality of bone regeneration and improve healing indices and consolidation times? (2) Is venting associated with a higher proportion of complications than nonventing? METHODS: We performed a retrospective study of femoral lengthening performed at one hospital from December 2012 to February 2022 using a magnetic intramedullary lengthening nail with or without venting at the osteotomy site before reaming. This was a generally sequential series, in which the study groups were assembled as follows: Venting was performed between July 2012 and August 2016 and again from November 2021 onward. Nonventing was used between October 2016 and October 2021 because the senior author opted to create drill holes after the reaming procedure to avoid commitment to the osteotomy level before completing the reaming procedure. Outcomes were evaluated based on bone healing time, time to achieve full weightbearing, and complications. Sixty-one femoral lengthening procedures were studied (in 33 male and 28 female patients); two patients were excluded because of implant breakage. The mean age was 17 ± 5 years. The mean amount of lengthening was 55 ± 13 mm in the venting group and 48 ± 16 mm in the nonventing group (mean difference 7 ± 21 [95% CI 2 to 12]; p = 0.07). The healing index was defined as the time (in days) required for three cortices to bridge with new bone formation divided by the length (in cm) lengthened during the clinical protocol. This index signifies the bone formation rate achieved under the specific conditions of the protocol. Full weightbearing was allowed upon bridging the regenerated gap on three sides. Consolidation time was defined as the total number of days from the completion of the lengthening phase until adequate bone union (all three cortices healed) was achieved and full weightbearing was permitted. This time frame represents the entire healing process after the lengthening is complete divided by the amount of lengthening achieved (in cm). Patient follow-up was conducted meticulously at our institution, and we adhered to a precise schedule, occurring every 2 weeks during the distraction phase and every 4 weeks during the consolidation phase. There were no instances of loss to follow-up. Every patient completed the treatment successfully, reaching the specified milestones of weightbearing and achieving three cortexes of bone bridging. RESULTS: The mean healing index time in the venting group was faster than that in the nonventing group (21 ± 6 days/cm versus 31 ± 22 days/cm, mean difference 10 ± 23 [95% CI 4 to 16]; p = 0.02). The mean consolidation time was faster in the venting group than the nonventing group (10 ± 6 days/cm versus 20 ± 22 days/cm; mean difference 10 ± 23 [95% CI 4 to 15]; p = 0.02). No medical complications such as deep vein thrombosis or fat or pulmonary embolism were seen. Two patients had lengthy delays in regenerate union, both of whom were in the nonventing group (healing indexes were 74 and 62 days/cm; consolidation time was 52 and 40 days/cm). CONCLUSION: Femoral lengthening with a magnetic intramedullary lengthening nail healed more quickly with prereaming venting than with nonventing, and it allowed earlier full weightbearing without any major associated complications. Future studies should evaluate whether there is a correlation between the number of venting holes and improvement in the healing index and consolidation time. LEVEL OF EVIDENCE: Level III, therapeutic study.
ABSTRACT
BACKGROUND: Surgery to achieve long bone lengthening and deformity correction in skeletally immature patients is traditionally performed through external fixators. The incidence of infection during treatment is high. Hydrotherapy is highly beneficial during external fixation management, but the infection rates may impact its utilization. The objective of this paper is to document the incidence and duration of infection in patients who participated in a full hydrotherapy program when performed under medical supervision and in accordance with strict follow-up protocols. METHODS: In this retrospective study, we documented the key characteristics of patients who participated in hydrotherapy after lower limb external fixation surgery including age, sex, diagnosis and surgery site, the incidence and duration of pin site infections, and the percentage of cases, which were able to comply with a full hydrotherapy protocol. RESULTS: The hydrotherapy pool met all daily water quality metrics. Thirty-four children (19 males and 15 females) had a mean±SD age of 10.9±4.6 years. Of the cases, 80% were unilateral and 20% were bilateral. Diagnoses included congenital hereditary (eg, achondroplasia), congenital nonhereditary conditions (eg, fibular hemimelia), and acquired conditions (eg, traumatic). The location of osteotomy site was quite evenly spread between the femur and the tibia/fibula. Three out of the 34 patients were unable to receive hydrotherapy due to continuous secretions; 2 patients did not miss any sessions. The mean number of treatments was 3 per week. During the entire period, a total of 1200 treatments were performed for these patients with only 32 cancellations (about 3%) due to secretions or other signs of infection. Spearman correlation coefficients showed significantly high correlations between the duration of external fixation and the duration of hydrotherapy. There are no significant correlations between infections and other factors (sex, age segment, whether the problem is unilateral or /bilateral, diagnosis, and duration of treatment). CONCLUSIONS: This is the first report, to our knowledge, that documents the low prevalence of infectious events during hydrotherapy treatment and demonstrates its feasibility. LEVEL OF EVIDENCE: Level III; retrospective, comparative study.
