What's New in Limb Lengthening and Deformity Correction

Radiographic findings involved in knee osteoarthritis progression are associated with pain symptom frequency and baseline disease severity: a population-level analysis using deep learning

PURPOSE

To (1) develop a deep-learning (DL) algorithm capable of producing limb-length and knee-alignment measurements, and (2) determine the association between limb-length discrepancy (LLD), coronal-plane alignment, osteoarthritis (OA) severity, and patient-reported knee pain.

METHODS

A multicenter, prospective patient cohort from the Osteoarthritis Initiative between 2004 and 2015 with full-limb standing radiographs at 12 month follow-up was included. A convolutional neural network was developed to automate measurements of the hip-knee-ankle (HKA) angle, femur, and tibia lengths, and LLD. At 12 month follow-up, patients reported their frequency of knee pain since enrollment and current level of knee pain.

RESULTS

A total of 1011 patients (2022 knees, 52.3% female) with an average age of 61.2 ± 9.0 years were included. The algorithm performed 12,312 measurements in 5.4 h. ICC values of HKA and LLD ranged between 0.87 and 1.00 when compared against trained radiologist measurements. Knees producing pain most days of the month were significantly more varus (mean HKA:- 3.9° ± 2.8°) or valgus (mean HKA:2.8° ± 2.3°) compared to knees that did not produce any pain (p < 0.05). In varus knees, those producing pain on most days were part of the shorter limb compared to nonpainful knees (p < 0.05). Baseline Kellgren-Lawrence grade was significantly associated with HKA magnitude, LLD, and pain frequency at 12 month follow-up (p < 0.05 all).

CONCLUSION

A higher frequency of knee pain was associated with more severe coronal plane deformity, with valgus deviation being one degree less than varus on average, suggesting that the knee tolerates less valgus deformation before symptoms become more consistent. Knee pain frequency was also associated with greater LLD and baseline KL grade, suggesting an association between radiographically apparent joint degeneration and pain frequency.

LEVEL OF EVIDENCE

IV case series.

Can Na18F PET/CT bone scans help when deciding if early intervention is needed in patients being treated with a TSF attached to the tibia: insights from 41 patients

Purpose

To demonstrate the usefulness of positron emission tomography (PET)/computed tomography (CT) bone scans for gaining insight into healing bone status earlier than CT or X-ray alone.

Methods

Forty-one prospective patients being treated with a Taylor Spatial Frame were recruited. We registered data obtained from successive static CT scans for each patient, to align the broken bone. Radionuclide uptake was calculated over a spherical volume of interest (VOI). For all voxels in the VOI, histograms and cumulative distribution functions of the CT and PET data were used to assess the type and progress of new bone growth and radionuclide uptake. The radionuclide uptake difference per day between the PET/CT scans was displayed in a scatter plot. Superimposing CT and PET slice data and observing the spatiotemporal uptake of ¹⁸F⁻ in the region of healing bone by a time-sequenced movie allowed qualitative evaluation.

Results

Numerical evaluation, particularly the shape and distribution of Hounsfield Units and radionuclide uptake in the graphs, combined with visual evaluation and the movies enabled the identification of six patients needing intervention as well as those not requiring intervention. Every revised patient proceeded to a successful treatment conclusion.

Conclusion

Numerical and visual evaluation based on all the voxels in the VOI may aid the orthopedic surgeon to assess a patient’s progression to recovery. By identifying slow or insufficient progress at an early stage and observing the uptake of ¹⁸F⁻ in specific regions of bone, it might be possible to shorten the recovery time and avoid unnecessary late complications.

Electronic supplementary material

The online version of this article (10.1007/s00590-020-02776-2) contains supplementary material, which is available to authorized users.

Excessive Aesthetic Lower Limb Elongation Management

Supplemental Digital Content is available in the text.

With the evolution of surgical techniques and increased availability of cosmetic orthopedic surgery, new complications manifest. Uncontrolled lower limb elongation without limitations can be achieved by disinformation and undergoing surgery in different countries. Patients receive excessive surgical intervention due to misinforming surgeons and clinics of their previous medical history. We present a previously undocumented case of excessive lower limb elongation in an adult male patient and a treatment method for this novel pathology. Lack of personal constraint and severe aesthetic discomfort led the patient to undergo 3 elongation procedures in 3 clinics in different countries. Correction of excessive elongation is a delicate procedure, which must account for previous medical history, the patient’s psychological status, and strict adherence to anatomical standards. In this case, we managed to correct the complications from hyper-elongation by restoring the normal anatomical proportions of the lower limbs. The patient consented to publication of these findings and has undergone psychiatric evaluation in a specialized clinic after corrective surgery. It is important to properly educate patients of surgical risks and to evaluate all aspects of patient psychosomatic well-being before surgical intervention. Advances in aesthetic medicine underline the development of new iatrogenic pathologies. Excessive lower limb elongation can lead to significant musculoskeletal deformation, requiring precise surgical correction with account to normal anatomical proportions.

Relevant advances in bone lengthening research: a bibliometric analysis of the 100 most-cited articles published from 2001 to 2017

This study aimed to assess the scientific production of bone lengthening research by identifying the most-cited papers. All articles including the term 'bone lengthening' published between 2001 and 2017 were retrieved through the Web of Science database. The 100 most-cited articles on bone lengthening included a total of 4244 citations, with 414 (9.7%) citations in 2017. There was an average of 249.6 citations per year. The articles predominantly addressed biomechanics and bone formation (38). Different surgical techniques, including intramedullary nail (14), Ilizarov (nine), intramedullary skeletal kinetic distractor (ISKD) (six), Taylor spatial frame (6), the PRECICE device (three), and lengthening and submuscular locking plate (three), were the second most-studied topic. Most studies were therapeutic (58), whereas 30 studies were experimental investigations using animal models. Among the clinical studies, case series were predominant (level of evidence IV) (57). This study presents the first bibliometric analysis of the most relevant articles on bone lengthening. The list is relatively comprehensive in terms of identifying the top issues in this field. However, the most influential clinical studies have a poor level of evidence, although a slight tendency toward a better level of evidence has been observed in more recent years.

Total hip arthroplasty and femoral nail lengthening for hip dysplasia and limb-length discrepancy

The application of distraction osteogenesis through the use of magnet-operated, remote-controlled intramedullary lengthening continues to provide new opportunities for accurate limb equalization. While limb-length discrepancy and deformity can be addressed by total hip arthroplasty alone, the magnitude of correction is limited by the soft-tissue envelope and complications such as sciatic nerve palsy. This 3-patient case series presents the combination of staged ipsilateral total hip arthroplasty and retrograde intramedullary femoral nail lengthening for the correction of both deformity and limb-length discrepancy. Our results report leg-length equalization, independent ambulation without assistive devices, and excellent bone and functional outcomes without complications, demonstrating that this combined technique can be used to achieve targeted lengthening and deformity correction.