Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Timothy P. Charlton is active.

Publication


Featured researches published by Timothy P. Charlton.


Foot & Ankle International | 2013

Limited Sinus Tarsi Approach for Intra-articular Calcaneus Fractures

Christian Kikuchi; Timothy P. Charlton; David B. Thordarson

Background: Operative treatment of calcaneal fractures has a historically high rate of wound complications, so the most optimal operative approach has been a topic of investigation. This study reviews the radiographic and clinical outcomes of the use of the sinus tarsi approach for operative fixation of these fractures with attention to the rate of infection and restoration of angular measurements. Methods: The radiographs and charts of 20 patients with 22 calcaneal fractures were reviewed to assess for restoration of angular and linear dimensions of the calcaneus as well as time to radiographic union. Secondary outcome measures included the rate of postoperative infection, osteomyelitis, revision surgeries, and nonunion. Results: We found a statistically significant restoration of Böhler’s angle and calcaneal width. Three of the 22 cases had a superficial wound infection. One patient had revision surgery for symptomatic hardware removal. There were no events of osteomyelitis, deep infection, malunion, or nonunion. Conclusion: We found that the sinus tarsi approach yielded similar outcomes to those reported in the literature. Level of Evidence: Level IV, retrospective case series.


Foot & Ankle International | 2012

Insertional Achilles tendinitis and Haglund's deformity.

Steve Kang; David B. Thordarson; Timothy P. Charlton

Background: Haglunds deformity is an enlargement of the posterosuperior prominence of the calcaneus, which is frequently associated with insertional Achilles tendinitis. To our knowledge, no study has been done successfully correlating the characteristics of a Haglunds deformity with insertional Achilles tendinitis. The purpose of our study was to analyze the characteristics of a Haglunds deformity in patients with and without insertional Achilles tendinitis to see if there was a correlation. Methods: The study was a retrospective radiographic review of a single surgeons patients with insertional Achilles tendinitis from 2005 to 2008. Our study population consisted of 44 patients, 48 heels (22 male, 22 female) with insertional Achilles tendinitis, with a mean age of 52 (range, 23 to 79) years. Our control population consisted of 50 patients (25 males, 25 females) and 50 heels without insertional Achilles tendinitis with a mean age of 55.6 (range, 18 to 89) years. We introduced two new measurements of the Haglunds deformity in this study: the Haglunds deformity height and peak angle. A standing lateral foot or ankle radiograph was analyzed for each patient and the following measurements were made: Haglund deformity height and peak angle; Bohlers angle; Fowler-Philip angle; and parallel pitch sign. We also looked for the presence of calcification in the study group and the length and width of the calcification. Unpaired t-test was used to analyze the measurements between the groups. Ten patients’ radiographs were re-measured and correlation coefficients were obtained to assess the reliability of the measuring techniques. Results: For the insertional Achilles tendinitis group, the mean Haglunds deformity height was 9.6 (range, 5.3 to 15.3) mm and the mean Haglunds deformity peak angle was 105 (range, 87 to 123) degrees. Calcification was present in 35 of 48 or (73%) of patients with a mean length of 13.3 (range, 3.2 to 41.9) mm and mean width of 4.5 (range, 1.0 to 10.4) mm. In the control group, the mean Haglunds deformity height was 9.0 (range, 5.2 to 12.1) mm and the peak angle was 105 (range, 91 to 124) degrees. Bohlers angle and Fowler-Philip angle were also similar between the groups and the positive parallel pitch sign was actually more prevalent in the control group (60% versus 41.7%). None of the differences in measurements between the groups achieved statistical significance. Conclusion: A Haglunds deformity was not indicative of insertional Achilles tendinitis and was present in asymptomatic patients. Also, a majority of the insertional Achilles tendinitis patients had calcification at the tendon insertion. We believe it is possible removing the Haglunds deformity may not be necessary in the operative treatment of insertional Achilles tendinitis. Level of Evidence: III, Retrospective Comparative Study


Clinics in Sports Medicine | 2008

Foot and Ankle Fractures in Dancers

Megan Goulart; Martin J. O'Malley; Christopher W. Hodgkins; Timothy P. Charlton

Fractures in the dance population are common. Radiography, CT, MRI, and bone scan should be used as necessary to arrive at the correct diagnosis after meticulous physical examination. Treatment should address the fracture itself and any surrounding problems such as nutritional/hormonal issues and training/performance techniques and regimens. Compliance issues in this population are a concern, so treatment strategies should be tailored accordingly. Stress fractures in particular can present difficulties to the treating physician and may require prolonged treatment periods. This article addresses stress fractures of the fibula, calcaneus, navicular, and second metatarsal; fractures of the fifth metatarsal, sesamoids, and phalanges; and dislocation of toes.


Foot & Ankle International | 2011

First Metatarsal Length Change after Basilar Closing Wedge Osteotomy for Hallux Valgus

Thomas Day; Timothy P. Charlton; David B. Thordarson

Background: Hallux valgus deformities with large intermetatar-sal angles require a more proximal metatarsal procedure to adequately correct the deformity. Due to the relative ease of a closing wedge osteotomy, this technique was adopted but with concern over first metatarsal shortening. In this study, we primarily evaluated angular correction and first metatarsal shortening. Materials and Methods: We evaluated 70 feet in 57 patients (average age, 54 years) with 52 female and five male. The average followup was 14 (range, 6 to 45) months. The charts were reviewed for the presence of metatarsalgia. Digital radiographic measurements were made for pre- and postoperative hallux valgus and intermetatarsal angles, dorsiflexion angle of the first metatarsal, and absolute and relative shortening of the first metatarsal. Results: The average hallux valgus angle improved from 31 to 11 degrees (p < 00001) and intermetatarsal angle from 13.2 to 4.4 angles (p < 00001). The absolute shortening of the first metatarsal was 2.2 mm and relative shortening was 0.6 mm. There was 1.3 degrees of dorsiflexion on average. Conclusion: Excellent correction of the deformity with minimal dorsiflexion or new complaints of metatarsalgia was found with this technique. The new method of assessing the relative shortening found to be less than the absolute shortening, which we feel more accurately reflects the functional length of the first metatarsal. Level of Evidence: IV, Retrospective Case Series


Sports Health: A Multidisciplinary Approach | 2014

Prevalence of abnormal vitamin D levels among division I NCAA athletes.

Diego Villacis; Anthony Yi; Ryan Jahn; Curtis J. Kephart; Timothy P. Charlton; Seth C. Gamradt; Russ Romano; James E. Tibone; George F. Rick Hatch

Background: Up to 1 billion people have insufficient or deficient vitamin D levels. Despite the well-documented, widespread prevalence of low vitamin D levels and the importance of vitamin D for athletes, there is a paucity of research investigating the prevalence of vitamin D deficiency in athletes. Hypothesis: We investigated the prevalence of abnormal vitamin D levels in National Collegiate Athletic Association (NCAA) Division I college athletes at a single institution. We hypothesized that vitamin D insufficiency is prevalent among our cohort. Study Design: Cohort study. Level of Evidence: Level 1. Methods: We measured serum 25-hydroxyvitamin D (25(OH)D) levels of 223 NCAA Division I athletes between June 2012 and August 2012. The prevalence of normal (≥32 ng/mL), insufficient (20 to <32 ng/mL), and deficient (<20 ng/mL) vitamin D levels was determined. Logistic regression was utilized to analyze risk factors for abnormal vitamin D levels. Results: The mean serum 25(OH)D level for the 223 members of this study was 40.1 ± 14.9 ng/mL. Overall, 148 (66.4%) participants had sufficient 25(OH)D levels, and 75 (33.6%) had abnormal levels. Univariate analysis revealed the following significant predictors of abnormal vitamin D levels: male sex (odds ratio [OR] = 2.83; P = 0.0006), Hispanic race (OR = 6.07; P = 0.0063), black race (OR = 19.1; P < 0.0001), and dark skin tone (OR = 15.2; P < 0.0001). Only dark skin tone remained a significant predictor of abnormal vitamin D levels after multivariate analysis (adjusted OR = 15.2; P < 0.0001). Conclusion: In a large cohort of NCAA athletes, more than one third had abnormal vitamin D levels. Races with dark skin tones are at much higher risk than white athletes. Male athletes are more likely than female athletes to be vitamin D deficient. Our study demonstrates a high prevalence of vitamin D deficiency among healthy NCAA athletes. Clinical Relevance: Many studies indicate a significant prevalence of vitamin-D insufficiency across various populations. Recent studies have demonstrated a direct relationship between serum 25(OH)D levels and muscle power, force, velocity, and optimal bone mass. In fact, studies examining muscle biopsies from patients with low vitamin D levels have demonstrated atrophic changes in type II muscle fibers, which are crucial to most athletes. Furthermore, insufficient 25(OH)D levels can result in secondary hyperparathyroidism, increased bone turnover, bone loss, and increased risk of low trauma fractures and muscle injuries. Despite this well-documented relationship between vitamin D and athletic performance, the prevalence of vitamin D deficiency in NCAA athletes has not been well studied.


Foot & Ankle International | 2013

Effect of Various Hallux Valgus Reconstruction on Sesamoid Location: A Radiographic Study

Eddie H. Huang; Timothy P. Charlton; Samuel Ajayi; David B. Thordarson

Background: The correction of sesamoid subluxation is an important component of hallux valgus reconstruction with some surgeons feeling that the sesamoids can be pulled back under the first metatarsal head when imbricating the medial capsule during surgery. The purpose of this study was to radiographically assess the effect of an osteotomy on sesamoid location relative to the second metatarsal. Methods: This is a retrospective radiographic study review of 165 patients with hallux valgus treated with reconstructive osteotomies. Patients were included if they underwent a scarf or basilar osteotomy for hallux valgus but were excluded if they had inflammatory arthropathy or lesser metatarsal osteotomy. A modified McBride soft tissue procedure was performed in conjunction with the basilar and scarf osteotomies. Each patient’s preoperative and postoperative radiographs were evaluated for hallux valgus angle, intermetatarsal 1-2 angle, tibial sesamoid classification, and lateral sesamoid location relative to the second metatarsal. Result: The greatest correction of both hallux valgus and intermetatrsal 1-2 angle was achieved in basilar osteotomies (20.6 degrees and 9.7 degrees, respectively), then scarf osteotomies (14.4 degrees and 8.7 degrees, respectively). Basilar and scarf osteotomies both corrected medial sesamoid subluxation relative to the first metatarsal head an average of 2-3 classification stages. All osteotomies had minimal lateral sesamoid location change relative to the second metatarsal. Conclusion: The majority of sesamoid correction correlated with the intermetatarsal 1-2 correction. The concept that medial capsular plication pulls the sesamoids beneath the first metatarsal (ie, changes the location of the sesamoids relative to the second metatarsal) was not supported by our results. Level of Evidence: Level III, retrospective case series.


Foot & Ankle International | 2014

Effectiveness and Complications Associated With Recombinant Human Bone Morphogenetic Protein-2 Augmentation of Foot and Ankle Fusions and Fracture Nonunions

Timothy Rearick; Timothy P. Charlton; David B. Thordarson

Background: Recombinant human bone morphogenetic protein-2 (rhBMP-2) has been used to augment bone healing and fusion in a variety of orthopaedic conditions. However, there is a paucity of data evaluating the potential benefits of its use in foot and ankle surgery. The purpose of this study was to investigate the effectiveness and associated complications with the use of rhBMP-2 in high-risk foot and ankle fusions and fracture nonunions. Methods: A total of 51 cases in 48 patients undergoing foot and ankle fusions or fracture nonunion revisions and considered at high risk for subsequent nonunion were identified through a retrospective review in which rhBMP-2 was used as an augment for bone healing. Rate of union, time to union, and associated complications were evaluated. Results: Forty-seven of 51 high-risk cases treated with rhBMP-2 united for a per-case union rate of 92.2%. Seventy-eight of 82 individual sites treated with rhBMP-2 united for a per-site union rate of 95.1%. Of the successful unions, the mean time to union was 111 days (95% confidence interval, 101-121). There were no statistically significant differences in time to union with regard to supplementation with bone allograft or autograft or size of rhBMP-2 kit used. Complication rates were low. Conclusion: rhBMP-2 was a safe and apparently effective adjunct to bony union in high-risk foot and ankle surgeries. Further randomized controlled trials are warranted. Level of Evidence: Level IV, retrospective case series.


Foot & Ankle International | 2013

Lateral Column Length in Adult Flatfoot Deformity

Steve Kang; Timothy P. Charlton; David B. Thordarson

Introduction: In adult acquired flatfoot deformity, it is unclear whether the lateral column length shortens with progression of the deformity, whether it is short to begin with, or whether it is short at all. To our knowledge, no previous study has examined the lateral column length of patients with adult acquired flatfoot deformity compared to a control population. The purpose of our study was to compare the lateral column length in patients with and without adult acquired flatfoot deformity to see if there was a significant difference. Methods: The study was a retrospective radiographic review of 2 foot and ankle fellowship-trained orthopaedic surgeons’ patients with adult flatfoot deformity. Our study population consisted of 75 patients, 85 feet (28 male, 57 female) with adult flatfoot deformity with a mean age of 64 (range, 23-93). Our control population consisted of 57 patients and 70 feet (23 male, 47 female) without flatfoot deformity with a mean age of 61 (range, 40-86 years). Weightbearing anteroposterior (AP) and lateral foot radiographs were analyzed for each patient, and the following measurements were made: medial and lateral column lengths, talonavicular uncoverage angle, talus-first metatarsal angle, calcaneal pitch angle, and medial and lateral column heights. An unpaired t test was used to analyze the measurements between the groups. Ten patients’ radiographs were remeasured, and correlation coefficients were obtained to assess the reliability of the measuring techniques. Results: For the flatfoot group, the mean medial and lateral column lengths on the AP radiograph were 108.6 mm and 95.8 mm, respectively; the mean talo-navicular uncoverage angle was 26.2 degrees; and the mean talus-first metatarsal angle was 20.0 degrees. In the control group, the mean medial and lateral column lengths on the AP radiograph were 108.8 mm and 96.5 mm, respectively; the mean talo-navicular uncoverage angle was 8.2 degrees; and the mean talus-first metatarsal angle was 7.7 degrees. On the lateral radiograph in the flatfoot group, the mean medial and lateral column lengths were 167.2 mm and 166.6 mm, respectively; the mean medial and lateral column heights were 16.0 mm and 14.7 mm, respectively; the mean calcaneal pitch angle was 15.6 degrees; and the talus-first metatarsal angle was 10.3 degrees and for the control group, the mean medial and lateral column lengths were 165.3 mm and 163.5 mm, respectively; the mean medial and lateral column heights were 22.8 mm and 13.1 mm, respectively; the mean calcaneal pitch angle was 22.4 degrees; and the talus-first metatarsal angle was −3.6 degrees. None of the differences in measurements for medial and lateral column lengths between the flatfoot and control groups achieved statistical significance. However, statistically significant differences between the 2 groups were observed in the measurements for medial and lateral column heights, talo-navicular uncoverage angle, calcaneal pitch angle, and talus-first metatarsal angle. Conclusion: There is no difference in lateral column lengths between patients with and without adult flatfoot deformity. The perceived shortened lateral column is likely due to forefoot abduction and hindfoot valgus deformities that are associated with adult flatfoot deformity. Level of Evidence: Level III, comparative series.


Foot & Ankle International | 2013

Ipsilateral intact fibula as a predictor of tibial plafond fracture pattern and severity.

Pamela C. Luk; Timothy P. Charlton; Jackson Lee; David B. Thordarson

Background: The objective of this study was to determine whether there is a difference in fracture pattern and severity of comminution between tibial plafond fractures with and without associated fibular fractures using computed tomography (CT). We hypothesized that the presence of an intact fibula was predictive of increased tibial plafond fracture severity. Methods: This was a case control, radiographic review performed at a single level I university trauma center. Between November 2007 and July 2011, 104 patients with 107 operatively treated tibial pilon fractures and preoperative CT scans were identified: 70 patients with 71 tibial plafond fractures had associated fibular fractures, and 34 patients with 36 tibial plafond fractures had intact fibulas. Four criteria were compared between the 2 groups: AO/OTA classification of distal tibia fractures, Topliss coronal and sagittal fracture pattern classification, plafond region of greatest comminution, and degree of proximal extension of fracture line. Results: The intact fibula group had greater percentages of AO/OTA classification B2 type (5.5 vs 0, P = .046) and B3 type (52.8 vs 28.2, P = .013). Conversely, the percentage of AO/OTA classification C3 type was greater in the fractured fibula group (53.5 vs 30.6, P = .025). Evaluation using the Topliss sagittal and coronal classifications revealed no difference between the 2 groups (P = .226). Central and lateral regions of the plafond were the most common areas of comminution in fractured fibula pilons (32% and 31%, respectively). The lateral region of the plafond was the most common area of comminution in intact fibula pilon fractures (42%). There was no statistically significant difference (P = .71) in degree of proximal extension of fracture line between the 2 groups. Conclusions: Tibial plafond fractures with intact fibulas were more commonly associated with AO/OTA classification B-type patterns, whereas those with fractured fibulas were more commonly associated with C-type patterns. An intact fibula may be predictive of less comminution of the plafond. The lateral and central regions of the plafond were the most common areas of comminution in tibial plafond fractures, regardless of fibular status. Level of Evidence: Level III, case control study.


Foot & Ankle International | 2012

Radiographic Assessment of Medial Cuneiform Opening Wedge Osteotomy for Flatfoot Correction

Deborah Castaneda; David B. Thordarson; Timothy P. Charlton

Background: Opening wedge osteotomy of the medial cuneiform has become an established intervention for correction of forefoot varus in relation to a flatfoot deformity. The purpose of this study was to use a newly described radiographic measurement to determine the effectiveness and durability of the medial column correction with a plantarflexion opening wedge osteotomy of the medial cuneiform without internal fixation using an allograft. Methods: Twenty-three feet underwent medial cuneiform opening wedge osteotomies for correction of forefoot varus associated with flatfoot deformity. The angle between the proximal and distal articular surfaces was measured on lateral radiographs preoperatively, postoperatively prior to weightbearing and at final followup visit. Results: The average angle between the proximal and distal articular surfaces of the medial cuneiform on lateral foot radiographs was 1.0 degree preoperatively (±0.8 degrees). The average angle postosteotomy, pre-weightbearing, was 8.4 degrees (±3.6 degrees) and at final followup was 7.5 degrees (±2.9 degrees). All patients achieved bony union. Conclusion: We describe a new radiographic measurement to focus on the correction achieved by a plantarflexion osteotomy of the medial cuneiform. It was found to be stable without internal fixation and reliably proceeded to union without significant loss of correction. Level of Evidence: IV, Retrospective Case Series

Collaboration


Dive into the Timothy P. Charlton's collaboration.

Top Co-Authors

Avatar

David B. Thordarson

University of Southern California

View shared research outputs
Top Co-Authors

Avatar

Anthony Yi

University of Southern California

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Danielle Thomas

Cedars-Sinai Medical Center

View shared research outputs
Top Co-Authors

Avatar

George F. Rick Hatch

University of Southern California

View shared research outputs
Top Co-Authors

Avatar

Steve Kang

University of Southern California

View shared research outputs
Top Co-Authors

Avatar

Allyson Estess

University of Southern California

View shared research outputs
Top Co-Authors

Avatar

Arush Patel

University of Southern California

View shared research outputs
Top Co-Authors

Avatar

Christian Kikuchi

University of Southern California

View shared research outputs
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge