A Prosthetic Socket with Active Volume Compensation for Amputated Lower Limb.

Typically, the actual volume of the residual limb changes over time. This causes the prosthesis to not fit, and then pain and skin disease. In this study, a prosthetic socket was developed to compensate for the volume change of the residual limb. Using an inflatable air bladder, the proposed socket monitors the pressure in the socket and keeps the pressure distribution uniform and constant while walking. The socket has three air bladders on anterior and posterior tibia areas, a latching type 3-way pneumatic valve and a portable control device. In the paper, the mechanical properties of the air bladder were investigated, and the electromagnetic analysis was performed to design the pneumatic valve. The controller is based on a hysteresis control algorithm with a closed loop, which keeps the pressure in the socket close to the initial set point over a long period of time. In experiments, the proposed prosthesis was tested through the gait simulator that can imitate a human's gait cycle. The active volume compensation of the socket was successfully verified during repetitive gait cycle using the weight loads of 50, 70, and 90 kg and the residual limb model with a variety of volumes. It was confirmed that the pressure of the residual limb recovered to the initial state through the active control. The pressure inside the socket had a steady state error of less than 0.75% even if the volume of the residual limb was changed from -7% to +7%.

Is surgery for brachial plexus schwannomas safe and effective?

BACKGROUND: Schwannomas rarely are found in the brachial plexus, and although they are benign, they present significant challenges to surgical treatment. To our knowledge, there are few studies investigating the surgical outcomes of patients with brachial plexus tumors. QUESTIONS/PURPOSES: We analyzed the outcomes of 19 patients with brachial plexus schwannomas and asked: (1) How do these patients present? (2) Where are the tumors located in the brachial plexus? (3) What are the complications and neurologic results of patients after excision of the tumor? METHODS: From February 2002 to August 2012, one orthopaedic hand surgeon treated 19 patients with schwannomas of the brachial plexus. We retrospectively reviewed the medical records and MRI data of all patients. There were 11 women and eight men, with a mean age of 50.2 years (range, 32-63 years). The tumor was located on the right side in eight patients and on the left in 11 patients. We evaluated neurologic deficits preoperatively and neurologic deficits and local recurrence of tumors postoperatively. Minimum followup was 12 months (mean, 37.2 months; range, 12-90 months). RESULTS: The most common initial presentation was a palpable mass. The masses were located at all levels along the brachial plexus, including the root, trunk, cord, and terminal branches. The smallest mass was 1.5 × 1.5 × 0.5 cm and the largest was 11 × 10 × 6 cm. Fourteen of the 19 patients did not have any postoperative neurologic deficits. All the removed masses were proven histologically to be schwannomas. Of the five patients who had postoperative neurologic deficits, three had transient sensory deficits, one had weakness of the flexor pollicis longus and second flexor digitorum profundus, and another had weakness of the extensor pollicis longus. No recurrence was observed during the followup period. CONCLUSIONS: Schwannomas of the brachial plexus are a potentially curable lesion with an acceptable surgical risk of injury to neurovascular structures. With precise surgical techniques, these tumors can be removed to improve symptoms with minimal morbidity. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

The effect of patient involvement in surgical decision making for carpal tunnel release on patient-reported outcome.

PURPOSE: To investigate whether patient-reported outcomes are different according to patients' preference or experience in surgical decision making for carpal tunnel release. METHODS: We preoperatively surveyed 85 patients who underwent carpal tunnel release regarding their preferred role in the process of surgical decision making and assessed their experienced role in the actual decision making 6 months after surgery using a Control Preference Scale. For patient-reported surgical outcomes, we used the Disabilities of the Arm, Shoulder, and Hand questionnaire. We compared these outcomes with those of patients having different preferences or experiences in surgical decision making and also compared the outcomes according to whether the preferred roles match the experienced roles. RESULTS: The Disabilities of the Arm, Shoulder, and Hand scores were not significantly different between patients with different preferences for involvement in decision making for surgery or between those with different experiences in the actual decision making. However, those who experienced the same level of involvement as they had preferred were found to have better Disabilities of the Arm, Shoulder, and Hand scores than those who experienced a more active role or a more passive role than they had preferred. CONCLUSIONS: This study demonstrates that patient-reported outcomes were not different between those with different preferences or experiences in surgical decision making for carpal tunnel release. However, this study suggests that patients whose experience in decision making matched with their preference may have better subjective outcomes after carpal tunnel release. This suggests that patients with carpal tunnel syndrome may benefit from physicians' efforts of identifying patients' preferences for involvement in decision making and matching the identified preferences to the decision-making process. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic II.

Early results of anterior elbow release with and without biceps lengthening in patients with cerebral palsy.

PURPOSE: To investigate the effect of partial biceps lengthening on elbow flexion posture and active elbow flexion and extension in patients with cerebral palsy. METHODS: We retrospectively reviewed 29 patients with cerebral palsy who underwent anterior elbow release as part of multilevel upper extremity surgery. The early series of the patients (N = 14; group 1) had lacertus fibrosus division, brachialis fractional lengthening, and denuding of the pretendinous adventitia off the biceps tendon. The later series of patients (N = 15; group 2) had partial biceps tendon lengthening in addition to the procedures in group 1. We compared the 2 sets of patients for elbow flexion posture, active elbow flexion and extension, forearm rotation, and House scores, with mean follow-ups of 72 months for group 1 and 31 months for group 2. RESULTS: The 2 groups were comparable in terms of mean age, number of procedures, and preoperative House scores. Group 2 patients had more improvement in flexion posture (53° vs. 44°) and active extension (23° vs. 15°) than group 1 postoperatively. However, group 2 had a mean decrease of 7° in active elbow flexion, whereas group 1 had no changes. There was no difference in forearm supination or in the improvement of House scores between groups. CONCLUSIONS: Early results of partial lengthening of the biceps tendon showed that it may improve elbow flexion posture and active elbow extension in patients with flexion deformity in cerebral palsy. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic III.

The effect of buffered lidocaine in local anesthesia: a prospective, randomized, double-blind study.

PURPOSE: Open carpal tunnel decompression under local anesthesia is routinely done by many surgeons. However, patients complain of pain during the injection of local anesthesia. This prospective, double-blind, randomized study was to compare the pain visual analog scale (VAS) scores of local anesthesia using lidocaine with and without sodium bicarbonate in patients with bilateral carpal tunnel syndrome. METHODS: Twenty-five patients underwent bilateral simultaneous carpal tunnel decompression. All had topical anesthetic cream applied on the palm and wrist before the lidocaine block. In a randomized manner, half of the hands were blocked with nonbuffered lidocaine and half were blocked with buffered lidocaine. Pain was evaluated on a VAS score. RESULTS: The mean pain VAS score in the hand with buffered lidocaine was 4.6 ± 1.5 and 6.5 ± 1.5 for the hand with nonbuffered lidocaine. After adjustment for individual threshold of the pain, the mean pain VAS score changed into 4.6 ± 1.3 with buffered lidocaine and 6.6 ± 1.7 without buffered lidocaine. CONCLUSIONS: In open carpal tunnel surgery, the use of buffered lidocaine for local anesthesia reduces the anesthetic pain effectively. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic I.

Radial polydactyly: proposal for a new classification system based on the 159 duplicated thumbs.

BACKGROUND: Polydactyly is one of the most common congenital differences that affect the hand. It has various anatomic and morphologic features. Although the Wassel classification has been used widely for radial polydactyly, it is based on the anatomic level of duplication and has some limitations in describing the concrete morphology of the duplication. The authors devised a new classification system based on the anatomic pattern of duplication to facilitate surgical correction of the deformity and evaluated surgical outcomes. METHODS: A total of 159 duplicated thumbs in 142 patients who were treated surgically from 1990 to 2007 and followed for > 12 months were included in this series. The authors categorized all cases of radial polydactyly into the following: type I (joint type), where the extra digit has its own joint at its origin; type II (single epiphyseal type), where the origin of the extra digit is derived directly from the common epiphysis; type III (osteochondroma-like type), where the origin of the extra digit resembles an osteochondroma; and type IV (hypoplastic type), where the extra digit is connected to the main digit by soft tissue alone. All patients underwent surgical treatment based on this classification. The surgical outcomes were assessed using the Tada score. RESULTS: Of the 159 radial polydactyly cases, 84 (50%) were classified as the joint type-37 (22%) as the osteochondroma-like type, 33 (19%) as the single epiphyseal type, and 15 (9%) as the hypoplastic type. All the cases were classified with the proposed classification system. In the evaluation of the surgical outcomes, 134 (84%), 17 (11%), and 8 (5%) were rated as good, fair, and poor, respectively. CONCLUSIONS: This new classification system for radial polydactyly is practical and closely related to the surgical strategies. LEVEL OF EVIDENCE: Diagnostic IV.

The impact of digit-related radiographic osteoarthritis of the hand on grip-strength and upper extremity disability.

BACKGROUND: Interpreting the impact of hand osteoarthritis (OA) on hand function is complicated owing to the multiple digits and joints in the hand. QUESTIONS/PURPOSE: We determined the impact of digit-related radiographic OA on hand function in patients 65 years or older. METHODS: We evaluated hand radiographs in 196 men and 182 women older than 65 years without shoulder or elbow pain who participated in the Korean Longitudinal Study on Health and Aging. Using the Kellgren and Lawrence criteria, we graded the 15 joints in each hand from 0 to 4 for OA, and evaluated hand function by measuring DASH scores and grip and pinch strength of dominant hands. We performed multiple linear regression analyses to evaluate associations between hand functions and the sum of Kellgren and Lawrence grade of each digit. RESULTS: The sums of Kellgren and Lawrence grades for thumbs and middle fingers were independently associated with grip strength, and the sums of the Kellgren and Lawrence grades for thumbs and index fingers were independently associated with pinch strength after controlling for age and sex. DASH scores were independently associated with OA of the thumb, or index or middle finger, but not with OA of the ring or small finger. CONCLUSIONS: This study revealed cumulative effects of joint involvement and Kellgren and Lawrence grades of thumb and middle finger OA on grip strength, and thumb and index finger OA on pinch strength. Furthermore, OA of either of three radial digits was associated with more severe upper extremity disabilities. LEVEL OF EVIDENCE: Level IV, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

Minimal epicondylectomy improves neurologic deficits in moderate to severe cubital tunnel syndrome.

BACKGROUND: Previous studies of minimal medial epicondylectomy for cubital tunnel syndrome included patients with mild disease, making it difficult to determine how much this procedure improved sensory and motor impairments in patients with moderate to severe disease. QUESTIONS/PURPOSES: We asked if minimal epicondylectomy improved sensory and motor impairments in patients with moderate to severe cubital tunnel syndrome. METHODS: We retrospectively reviewed 25 patients treated with minimal medial epicondylectomy for advanced cubital tunnel syndrome involving motor weakness between January 2003 and February 2009. Preoperatively, five patients had Medical Research Council (MRC) Grade 4 motor strength without atrophy (McGowan Grade IIA), nine had MRC Grade 3 motor strength with detectable atrophy (McGowan Grade IIB), and 11 had MRC Grade 3 or less motor strength with severe atrophy (McGowan Grade III). Postoperatively we obtained DASH scores and evaluated improvement of sensory impairment and motor impairment: excellent with minimal sensory deficit and motor deficit, good with mild deficits, fair with improved but persistent deficit(s), and poor with no improvement. The minimum followup was 13 months (mean, 46 months; range, 13-86 months). RESULTS: The mean DASH score was 14 points (range, 2-47 points). Of the 25 patients, sensory improvement and motor improvement were excellent in 16 patients, good in five, fair in two, and poor in two. Twenty-three of the 25 patients improved at least one McGowan grade. There were no complications, such as medial elbow instability. CONCLUSIONS: Minimal medial epicondylectomy can improve sensory and motor impairments for patients with moderate to severe cubital tunnel syndrome. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the guidelines for authors for a complete description of levels of evidence.

The radiologic relationship of the shoulder girdle to the thorax as an aid in diagnosing neurogenic thoracic outlet syndrome.

PURPOSE: Neurogenic thoracic outlet syndrome (NTOS) is produced by compression of the brachial plexus in the thoracic outlet. The lower position of the shoulder girdle relative to the upper thorax may be related to NTOS. We investigated this hypothesis using plain cervical radiographs. METHODS: We conducted this case-control study using plain cervical anteroposterior and lateral radiographs in 63 NTOS patients and 126 carpal tunnel syndrome patients who were matched for age and sex. To estimate the position of the shoulder girdle relative to the upper thorax, we analyzed the level of the clavicle using 2 parameters: the number of vertebrae visible in a lateral radiograph and the number of vertebrae above the line connecting both sternal ends of the clavicles in an anteroposterior radiograph. The number of vertebrae visible in a lateral radiograph was the parameter for the level of the lateral part of the clavicle relative to the upper thorax, whereas we used the number of vertebrae above the line connecting both sternal ends of the clavicles in an anteroposterior radiograph to determine the level of the medial part of the clavicle. RESULTS: Both parameters were greater in the NTOS group than in the control group, which suggests that the level of the shoulder girdle was lower in the NTOS group than in the control group. In addition, the risk of NTOS was increased in patients with lower shoulder girdle position. CONCLUSIONS: The lower placement of the shoulder girdle relative to the upper thorax was related to NTOS. Physicians may be able to estimate the position of the shoulder girdle using plain cervical radiographs when NTOS is clinically suspected. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic IV.

Effect of passive stretching on simple camptodactyly in children younger than three years of age.

PURPOSE: To present the effectiveness of passive stretching as a treatment for camptodactyly, without any other form of physiotherapy or splinting. METHODS: From May 2003 to August 2008, 61 digits of 22 patients were treated conservatively using passive stretching exercises. All children were less than 3 years old and had no other anomalies. Flexion contractures before and after treatment in mild, moderate, and severe groups were measured and changes were analyzed statistically. The correlations between various clinical factors and treatment outcome were also analyzed statistically. The average follow-up period was 26 months (range, 12-47 mo). RESULTS: Mean flexion contracture improved from 20° to 1° in the mild group (p < .001), from 39° to 12° in the moderate group (p < .001), and from 75° to 28° in the severe group (p < .001). Of the clinical factors examined, only initial flexion contracture was found to be significantly correlated with treatment outcome (r = -0.287, p = .0025). CONCLUSIONS: Passive stretching can effectively improve flexion deformity in camptodactyly in infants and young children. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

A built-up-type deformable phantom for target motion control to mimic human lung respiration.

Existing human lung-mimicking requirements in various radiology application fields have led to the development of many different phantoms. However, most are static apparatus designed for equipment calibration. Although there are a few dynamic phantoms that generate predefined motions, they have complicated mechanisms that hamper even simple modifications for various lung illness simulations. As a result, existing dynamic phantoms in which a target can be embedded normally generate rectilinear target motions with limited displacement. Nevertheless, volume changes in the human lungs during normal respiration are significant, and targets inside the lungs move along various random paths depending on their location, stiffness, and the properties of the surrounding tissues. In the present work, a novel phantom design is introduced and tested. The phantom mimics the human lung motion and its deformation is initiated by a diaphragm movement. The phantom provides a fairly large deformation and the capability to adjust target motion paths. The presented device has a simple mechanism that can be easily modified to generate various pulmonary diseases. To produce a large deformation by diaphragm compressive motion, polyurethane cubic blocks constitute the deformable part of the lung phantom and a tumor made with silicone is inserted in the structure. The assembled lung part is housed within an acrylic case that is filled with water. The phantom system consists of acrylic, plastic, and low-density polyurethane to minimize artifacts when it undergoes computed tomography (CT) scans. The lung part is organized with various density polyurethane blocks, making it possible to produce nonlinear motion paths of the tumor. The lung part is deformed by a silicon film that is driven by external hydraulic pressure. A finite element method simulation and two-dimensional target motion tests were performed to verify phantom performance. The functionality of the proposed phantom system was confirmed in a series of CT images.

Baby Genomics: Tracing the Evolutionary Changes That Gave Rise to Placentation.

It has long been challenging to uncover the molecular mechanisms behind striking morphological innovations such as mammalian pregnancy. We studied the power of a robust comparative orthology pipeline based on gene synteny to address such problems. We inferred orthology relations between human genes and genes from each of 43 other vertebrate genomes, resulting in ∼18,000 orthologous pairs for each genome comparison. By identifying genes that first appear coincident with origin of the placental mammals, we hypothesized that we would define a subset of the genome enriched for genes that played a role in placental evolution. We thus pinpointed orthologs that appeared before and after the divergence of eutherian mammals from marsupials. Reinforcing previous work, we found instead that much of the genetic toolkit of mammalian pregnancy evolved through the repurposing of preexisting genes to new roles. These genes acquired regulatory controls for their novel roles from a group of regulatory genes, many of which did in fact originate at the appearance of the eutherians. Thus, orthologs appearing at the origin of the eutherians are enriched in functions such as transcriptional regulation by Krüppel-associated box-zinc-finger proteins, innate immune responses, keratinization, and the melanoma-associated antigen protein class. Because the cellular mechanisms of invasive placentae are similar to those of metastatic cancers, we then used our orthology inferences to explore the association between placenta invasion and cancer metastasis. Again echoing previous work, we find that genes that are phylogenetically older are more likely to be implicated in cancer development.

Radiological characteristics of Kienböck's disease in the Korean population.

PURPOSE: In Kienböck's disease, the wrist displays certain characteristic radiological parameters, which have been reported to differ among countries. In the present study, we aimed to identify specific radiological parameters of the unaffected wrists in patients with unilateral Kienböck's disease and to determine the extent of the association of each parameter with the disease in Korea. METHODS: This retrospective case-control study assessed the radiological parameters of patients with Kienböck's disease ( n = 53) and controls ( n = 53), who visited our institution between January 2000 and May 2013. Ulnar variance (UV), radial inclination, lunate fossa inclination, lunate diameter, lunate height, lunate tilting angle (LTA), lunate covering index (LCI), and Ståhl index (SI) were measured and analyzed using a binary logistic regression model. RESULTS: We observed that wrists with a high LTA and LCI, and low UV and SI had a tendency to develop Kienböck's disease. CONCLUSION: In the Korean population, a high LTA and LCI, and low UV and SI of the unaffected wrists on plain radiography might be associated with Kienböck's disease. The radiographic characteristics of the unaffected wrists can differ between patients with unilateral Kienböck's disease and normal individuals.

Diet shifts provoke complex and variable changes in the metabolic networks of the ruminal microbiome.

BACKGROUND: Grazing mammals rely on their ruminal microbial symbionts to convert plant structural biomass into metabolites they can assimilate. To explore how this complex metabolic system adapts to the host animal's diet, we inferred a microbiome-level metabolic network from shotgun metagenomic data. RESULTS: Using comparative genomics, we then linked this microbial network to that of the host animal using a set of interface metabolites likely to be transferred to the host. When the host sheep were fed a grain-based diet, the induced microbial metabolic network showed several critical differences from those seen on the evolved forage-based diet. Grain-based (e.g., concentrate) diets tend to be dominated by a smaller set of reactions that employ metabolites that are nearer in network space to the host's metabolism. In addition, these reactions are more central in the network and employ substrates with shorter carbon backbones. Despite this apparent lower complexity, the concentrate-associated metabolic networks are actually more dissimilar from each other than are those of forage-fed animals. Because both groups of animals were initially fed on a forage diet, we propose that the diet switch drove the appearance of a number of different microbial networks, including a degenerate network characterized by an inefficient use of dietary nutrients. We used network simulations to show that such disparate networks are not an unexpected result of a diet shift. CONCLUSION: We argue that network approaches, particularly those that link the microbial network with that of the host, illuminate aspects of the structure of the microbiome not seen from a strictly taxonomic perspective. In particular, different diets induce predictable and significant differences in the enzymes used by the microbiome. Nonetheless, there are clearly a number of microbiomes of differing structure that show similar functional properties. Changes such as a diet shift uncover more of this type of diversity.

Heparin-immobilized biodegradable scaffolds for local and sustained release of angiogenic growth factor.

Heparin-immobilized porous biodegradable scaffolds were fabricated to release basic fibroblast growth factor (bFGF) in a sustained manner. Heparin was covalently conjugated onto the surface of macroporous PLGA scaffolds fabricated by a gas-foaming/salt-leaching method. Sustained release of bFGF was successfully achieved for over 20 days due to high affinity of bFGF onto the immobilized heparin. It appears that bFGF release rate was regulated by the specific interaction between bFGF and heparin. The bFGF fraction released from the scaffolds maintained its bioactivity, as judged from determining the proliferation extent of human umbilical vein endothelial cells (HUVECs) in vitro. When heparin-immobilized scaffolds loaded with bFGF were implanted subcutaneously in vivo, they effectively induced the formation of blood vessels in the vicinity of the implant site. This study demonstrated that local and sustained delivery of angiogenic growth factor for tissue regeneration could be achieved by surface modification of porous scaffolds with heparin.

Master device for teleoperated needle insertion-type interventional robotic system.

This paper proposes a new master device for teleoperated needle insertion-type interventional robotic system. The 5-DOF master device is optimally designed based on the newly defined interventional procedures and the physicians' requirements. It comprises a 2-DOF rotational mechanism for adjustment of needle orientation, a 2-DOF translational mechanism for fine-tuning of needle entry point, and a handle assembly. The handle assembly includes a 1-DOF translational mechanism for needle insertion and buttons for operation mode selection. The passive actuation modules of the rotational mechanism and the active actuation modules of the translational mechanism are controlled appropriately for the selected mode according to the procedure phase. The needle insertion mechanism also warns the user by vibrating the shaft when the needle reaches the dangerous region.

Ulnar Neuropathy After Extracorporeal Shockwave Therapy: A Case Report.

Currently, extracorporeal shockwave therapy (ESWT) is widely used for treatment of various musculoskeletal disorders. We report a case of ulnar neuropathy secondary to the application of ESWT. A 48-year-old man was diagnosed with medial epicondylitis and underwent 2 sessions of ESWT. Immediately after the second session, he experienced paresthesia and weakness in the right hand. On physical examination, atrophy of the first dorsal interosseus and weakness of the abductor digiti minimi were observed. Electrophysiologic study demonstrated ulnar neuropathy at the elbow with severe partial axonotmesis. Our case report demonstrates that ESWT might cause or contribute to peripheral nerve injury at the site of application.

Compartment syndrome due to extravasation of peripheral parenteral nutrition: extravasation injury of parenteral nutrition.

Compartment syndrome is a rare but devastating condition that can result in permanent neuromuscular or soft tissue injuries. Extravasation injuries, among the iatrogenic causes of compartment syndrome, occur under a wide variety of circumstances in the inpatient setting. Total parenteral nutrition via a peripheral route is an effective alternative for the management of critically ill children who do not obtain adequate nutrition via the oral route. However, there is an inherent risk of extravasation, which can cause compartment syndrome, especially when detected at a later stage. Herein, we report a rare case of compartment syndrome and skin necrosis due to extravasation, requiring emergency fasciotomy and skin graft in a 7-month-old boy who was treated with peripheral parenteral nutrition via a pressurized infusion pump. Although we cannot estimate the exact time at which extravasation occurred, the extent and degree of the wound suggest that the ischemic insult was prolonged, lasting for several hours. Pediatric clinicians and medical teams should carefully examine the site of insertion of the intravenous catheter, especially in patients receiving parenteral nutrition via a peripheral intravenous catheter with a pressurized infusion pump.

Posterolateral rotatory instability of the elbow after corrective osteotomy for previously asymptomatic cubitus varus deformity.

BACKGROUND: We identified a subset of patients who had posterolateral rotatory instability (PLRI) following corrective osteotomy for asymptomatic cubitus varus deformity. We aimed to identify risk factors for PLRI in such patients by comparing this subgroup to patients who did not demonstrate PLRI following osteotomy. METHODS: We retrospectively reviewed the medical records and radiographs of 22 patients with cubitus varus that underwent corrective osteotomy at our institution between 2003 and 2010. All patients underwent surgery for cosmetic reasons, and no patient reported functional problems such as PLRI or ulnar nerve symptoms pre-operatively. We sought to identify differences between those that experienced an increase in PLRI after osteotomy (PLRI group) and those that did not (non-PLRI group) with regard to demographics, degree of deformity, amount of surgical correction, and final outcomes. RESULTS: Five patients had PLRI after osteotomy, and all five subsequently underwent lateral ulnar collateral ligament reconstruction using a triceps tendon graft. No statistically significant difference was observed between the PLRI and non-PLRI groups in terms of demographics, degree of deformity, amount of surgical correction, range of motion, and final Mayo Elbow Performance Index (MEPI) and the Disabilities of Arm, Shoulder, and Hand (DASH) scores. However, the PLRI group had marginally greater medial displacement of the distal fragment. CONCLUSIONS: This study demonstrates that PLRI can become apparent after corrective osteotomy for cubitus varus in the absence of clinical symptoms of instability preoperatively. We suggest that careful examination for PLRI should be performed after surgical correction for cubitus varus deformity, and surgeons should be prepared to proceed with simultaneous reconstruction of the lateral ligaments of the elbow.