Prospective Multicenter Preliminary Validation of Limb Deformity-modified Scoliosis Instruments in Pediatric Patients With Limb Deformity.

INTRODUCTION: There are few disease-specific patient-reported outcome measures (PROMs) for use in pediatric limb deformity (LD), with authors instead relying on generic PROMs such as the Pediatric Outcomes Data Collection Instrument (PODCI) to assess treatment outcomes from the patient's perspective. The purpose of this study was to perform preliminary validation of 2 disease-specific PROMs in pediatric patients with LD. METHODS: LD modifications were created by substituting the word "limb" for "back" in the Early Onset Scoliosis Questionnaire (EOSQ, ages 10 and younger) and the Scoliosis Research Society (SRS, ages 11 to 18) survey, creating the LD-EOSQ and LD-SRS instruments. Children were preoperatively administered the age-appropriate LD-PROMs (n=34 LD-EOSQ; n=30 LD-SRS) and PODCI questionnaires. LD-PROMs were assessed for construct (convergent and discriminant) validity, floor and ceiling effects, content validity, and minimal clinically important difference. RESULTS: Both LD-EOSQ and LD-SRS demonstrated excellent preliminary convergent validity with similar PODCI domains and discriminant validity with demographic information, deformity data, and LLRS-AIM scores. There were minimal floor or ceiling effects. Content validity was achieved in 100% of LD-EOSQ surveys and more than 80% of LD-SRS surveys. Minimal clinically important difference was 0.4 for LD-EOSQ and 0.3 for LD-SRS. CONCLUSIONS: The LD-EOSQ for patients aged 10 and under and LD-SRS for patients aged 11 to 18 demonstrated preliminary validity and reliability in the pediatric LD population. These measures provide more information specifically related to familial impact in younger children and self-image and mental health in adolescents compared to the PODCI and should be further evaluated for use in these patients. LEVEL OF EVIDENCE: Level II-diagnostic. Prospective cross-sectional cohort design.

The Influence of Retrograde Femoral Nail Removal With and Without Interpositional Fat Grafting on Distal Femoral Physeal Behavior: A Sheep Study.

BACKGROUND: Previous investigations have demonstrated that up to 7% of the distal femoral physis can be violated using a rigid, retrograde nail without growth inhibition or arrest. The purpose of this investigation was to evaluate the behavior of the distal femoral physis after retrograde femoral nail removal in a sheep model, with and without placement of an interpositional fat graft. METHODS: Retrograde femoral nails were placed in 8 skeletally immature sheep. Implants were removed at 8 weeks, with the residual defects left open (n=4) or filled with autologous fat graft (n=4). Differences in femoral length between surgical versus contralateral control femurs were measured after an additional 3 (n=4) or 5 months (n=4) before sacrifice, and the physis was evaluated histologically. RESULTS: When compared with control limbs, femoral length was significantly shorter in limbs sacrificed at 3 months (mean: 3.9±1.3 mm; range: 2.7 to 5.7 mm) compared with limbs at 5 months (mean: 1.0±0.4 mm; range: 0.4 to 1.2 mm) ( P =0.005). No significant difference in mean shortening was appreciated in limbs without (2.4±1.6 mm) versus with fat grafting (2.5±2.3 mm) ( P =0.94). Histologic analysis revealed no osteoid formation across the physis in sheep sacrificed at 3 months, whereas there was evidence of early osteoid formation across the physis in sheep at 5 months. All specimens demonstrated evidence of an active physes. CONCLUSIONS: Femurs undergoing retrograde implant placement were significantly shorter when compared with control limbs in sheep sacrificed at 3 months, whereas differences were nominal in sheep sacrificed at 5 months after retrograde implant removal, suggesting growth inhibition with nail removal improved with time. Fat grafting across the distal femoral physis did not result in a significant difference in femoral lengths. Histologic evidence at 5 months revealed early development of a bone bridge, emphasizing the importance of follow-up to skeletal maturity in patients treated with retrograde nailing across an open physis. LEVEL OF EVIDENCE: Level IV.

The distal femur trochlear groove appears to compensate for tibial deformity but not femoral deformity in an investigation of five-hundred and seventy-nine cadaveric skeletons.

BACKGROUND: The etiology of patellofemoral disorders is multifactorial. Preoperative patellofemoral anatomy evaluation is of great importance in patients undergoing surgery for patellofemoral disorders. Although anatomical risk factors of patellofemoral disorders have been thoroughly investigated in clinical and radiological studies, there are sparse data regarding the association between trochlear dysplasia with other anatomical parameters. This study sought to explore those associations using a large osteological collection. METHODS: Five-hundred and seventy-nine cadaveric skeletons were obtained from the Hamann-Todd osteological collection. Mechanical lateral distal femoral angle (mLDFA), medial proximal tibial angle (MPTA), femoral version, tibial torsion, lateral position of the tibial tubercle, and femoral length were modeled as predictors of medial and lateral flange height of the distal femur trochlea at various degrees of knee flexion. RESULTS: The average age and standard deviation for the 1158 lower extremities analyzed was 55.9 ± 10.2 years. There were 500 males (86%) and 79 females. Increasing MPTA or tibial valgus predicted increasing lateral femoral flange height at 0, 30, and 50 degrees of knee flexion [(standardized beta 0.111, p = 0.01), (standardized beta 0.129, p < 0.001), and (standardized beta 0.186, p < 0.001), respectively]. Increasing internal tibial torsion predicted increased medial flange height at 30 and 50° [(standardized beta - 0.114, p = 0.006), (standardized beta - 0.108, p = 0.006), respectively]. Increased femoral retroversion predicted increasing lateral flange height at 0 and 30 degrees [(standardized beta - 0.105, p = 0.005), (standardized beta - 0.098, p = 0.004), respectively]. CONCLUSIONS: To maintain the equilibrium necessary for effective patellar tracking, the depth of trochlear groove appears to effectively compensate for some of the anatomical parameters of the proximal tibia associated with patellofemoral disorders, and appears to be less influenced by femoral alignment. The clinical relevance of these findings warrants further investigation, and emphasizes the importance of carefully assessing the lower limb alignment in the management of patellofemoral disorders.

Torsional Deformity Significantly Impacts Lateral Ankle Radiographic Imaging Parameters.

Background Optimal lateral ankle imaging is important for the diagnosis and treatment of multiple ankle conditions. The effects of limb deformity on lateral ankle imaging are not well described and are clarified in this osteological study. Materials and methods We utilized an osteological collection and imaged all specimens after the first positioning of the talus in the lateral position and positioning the tibia and fibula to match. We then measured the relative positions of the tibia and fibula and their widths to calculate standard ratios. All measurements were evaluated for reliability using intra-class correlation coefficients. Multiple regression analysis determined how patient characteristics, tibial torsion, and medial proximal tibial angle affected various lateral ankle imaging ratios. Results The intra-class correlation coefficient was excellent for all measurements. In the multiple regression analysis, all five imaging ratios had at least one statistically significant outcome. The anterior tibiofibular interval (ATFI)-tibial width (TW) ratio (ATFI:TW) had only one association with sex and had the lowest standard deviation. All other parameters had variation with tibial torsion and/or medial proximal tibia angle (MPTA). The mean ATFI was 1.06 ± 0.21 cm and 1.19 ± 0.23 cm for females and males, respectively. Conclusions Patient sex and tibial torsion impacted the fidelity of lateral imaging parameters. ATFI:TW may pose the greatest utility given its minimal association with deformity parameters and low standard deviation.

A Cadaveric Anatomical Study of the Relationship between Proximal Tibial Slope and Coronal Plane Deformity.

Medial proximal tibial angle (MPTA) and posterior proximal tibial angle (PPTA) are commonly used to characterize the geometry of proximal tibia and are important considerations in lower extremity realignment procedures and total knee arthroplasty. This study utilized a large cadaveric collection to explore relationships between tibial slope and coronal plane deformity of the tibia. We utilized 462 well-preserved skeletons (924 tibiae), excluding any with fracture or obvious rheumatologic or infectious findings. Custom cards were made with different sized arcs on the bottom surface, so that they could rest on the anterior and posterior aspects of the medial and lateral tibial plateaus of each bone to measure PPTA. Previously measured MPTA values for the same bones were also utilized. Multiple regression analysis was used to determine relationship between MPTA and medial and lateral PPTAs. The mean age was 56 ± 10 years, with 13% female and 31% African American (remainder Caucasian). The mean MPTA was 87.2 ± 2.4 degrees. The mean medial plateau PPTA was 81.5 ± 3.8 degrees and mean lateral plateau PPTA was 81.3 ± 3.7 degrees. Regression analysis found that MPTA was significantly associated with both medial and lateral PPTAs (standardized betas 0.197 and 0.146, respectively, p < 0.0005 for both). There was a significant correlation between lateral and medial PPTAs (r = 0.435, p = 0.03). The clinical significance of these findings warrants further investigation and emphasizes the importance of carefully assessing the sagittal plane when planning reconstruction of a tibia with varus or valgus deformity, particularly high tibial osteotomies.

Current use of patient-reported outcomes in pediatric limb deformity surgery.

Patient-reported outcome (PRO) instruments are critical to evaluate the natural history of conditions and treatment effects, but have not been well studied in pediatric limb deformity. The goal of this study was to identify and assess the most commonly used PROs in pediatric limb deformity surgery across a representative sample of the recent orthopedic literature. A review was performed from 1 January 2016 to 31 December 2018 in five orthopedic journals previously identified as having the greatest impact: Journal of Pediatric Orthopaedics, Journal of Pediatric Orthopaedics B, Journal of Children's Orthopaedics, The Journal of Bone and Joint Surgery, and The Bone and Joint Journal. Clinical research studies involving pediatric population, operative management of limb deformity, and PRO measures were reviewed. The initial search of 3489 publications found 130 clinical articles involving operative management of pediatric limb deformity. Thirty-one studies (24%) met inclusion criteria, in which a total of 23 different PRO instruments were used. An average of 1.5 PRO instruments was reported per study (range 1-4). No outcome instrument was used by more than five different studies in this review, and no instrument validated in the pediatric population was used by more than three different studies. PROs currently used in pediatric limb deformity surgery are highly heterogeneous, as well as underutilized. Future research is necessary to either validate a current PRO in pediatric limb deformity or to develop a new instrument using pediatric Patient-Reported Outcomes Measurement Information System or Pediatric Outcomes Data Collection Instrument as a benchmark.