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Dive into the research topics where Christopher Kreulen is active.

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Featured researches published by Christopher Kreulen.


American Journal of Sports Medicine | 2012

Demographic Trends in Arthroscopic SLAP Repair in the United States

Alan L. Zhang; Christopher Kreulen; Stephanie S. Ngo; Sharon L. Hame; Jeffrey C. Wang; Seth C. Gamradt

Background: Treatment of superior labral anterior posterior (SLAP) tears remains controversial, particularly in older age groups. Repair, debridement, biceps tenodesis, tenotomy, and observation have been recommended depending on patient characteristics, but there have not been any large epidemiologic studies investigating treatment trends. Purpose: To investigate current trends in SLAP repair across time, gender, age, and regions in the United States. Study Design: Descriptive epidemiology study. Methods: Patients who underwent arthroscopic SLAP repair (Current Procedural Terminology [CPT] code 29807) were identified using a publicly available national database of insurance records (PearlDiver Patient Records Database) during years 2004 through 2009. Factors identified for each patient included gender, age group, and region in the United States. Logistic regression analysis and the chi-square test were used for statistical measures. Results: From 2004 to 2009 there were 25,574 cases of arthroscopic SLAP repair identified, of which 75% were male patients and 25% were female patients. There was a significant rise in cases of SLAP repair from 2004 to 2009 as the incidence of SLAP repair increased from 17.0 for every 10,000 patients with an orthopaedic International Classification of Diseases, Ninth Revision (ICD-9) or CPT code in 2004 to 28.1 in 2009 (P < .0001). Age analysis revealed the highest incidence in the 20-29–year (29.1 per 10,000) and 40-49–year (27.8 per 10,000) age groups. Men (37.3 per 10,000) had a significantly higher incidence of repairs than did women (10.7 per 10,000). The West (24.6 per 10,000) and South (24.4 per 10,000) regions also demonstrated a higher incidence than the Midwest (20.5 per 10,000) and Northeast (20.1 per 10,000) regions (P < .0001). Conclusion: Our analysis illustrates that surgeons are performing significantly more arthroscopic SLAP repairs each year. The highest incidence of repair is in the 20-29– and 40-49–year age groups, and a significant gender difference exists, with men having a threefold higher incidence of repair.


Foot and Ankle Clinics of North America | 2015

Subtalar Joint Arthrodesis: Open and Arthroscopic Indications and Surgical Techniques

Brent Roster; Christopher Kreulen; Eric Giza

Arthrodesis of the subtalar joint can be performed via both open and arthroscopic techniques. Both groups of procedures have their own relative indications and contraindications, as well as complications. Good results have been reported for both general procedures, although some studies suggest superiority with arthroscopic subtalar arthrodesis.


Foot & Ankle International | 2014

Viability of talus osteochondral defect cartilage for chondrocyte harvesting: results of 151 patients.

Christopher Kreulen; Eric Giza; Jason Kim; Valentina Campanelli; Martin Sullivan

Background: Large talar cartilage defects can be treated with either autologous chondrocyte implantation or matrix autologous chondrocyte implantation. Both techniques depend on successful harvesting of the chondrocytes. In the past, they have come from the ipsilateral knee, which has been associated with donor site morbidity. We hypothesized that damaged cartilage from the talus can be used as a reliable source for chondrocyte cell harvesting in preparation for possible matrix-induced autologous chondrocyte implantation (MACI). Methods: Chondrocytes were harvested from the injured talar cartilage during ankle arthroscopy and sent to a cell laboratory, measured for initial biopsy weight, cultured for 4 to 6 weeks, and then analyzed for viability. A total of 151 patients were analyzed. Results: The average biopsy initial weight was 187.1 mg. The average number of cells was 3.13 × 105. The viability of the chondrocytes provided by the manufacturer averaged 92.3% (range, 33%-100%). Conclusions: Chondrocytes harvested from the damaged talar articular cartilage were functional and proliferated with an average viability of 92%. Clinical Relevance: This technique may provide a useful source of chondrocytes if needed for a future cell-based regenerative procedure such as MACI while eliminating the need to harvest chondrocytes from the knee or other intact areas of cartilage on the talus. Level of Evidence: Level IV, case series.


Foot and Ankle Specialist | 2010

Tibiotalar Nonunion Corrected by Hindfoot Arthrodesis

Eric Giza; Annahita Sarcon; Christopher Kreulen

A 65-year-old man without significant comorbidities was referred to the senior author (EG) 9 months after an ankle arthrodesis procedure with complaints of pain, swelling, and progressive hindfoot valgus. The patient had elected to have the index surgery because of severe ankle arthritis due to longstanding lateral ankle instability. Physical examination revealed a well-healed anterior, midline ankle incision with normal pulses and sensation. Painful, limited ankle and subtalar range of motion was noted along with 20 degrees of hindfoot valgus and subfibular impingement. Radiographs of the ankle revealed an attempted ankle fusion using a knee arthroplasty trabecular metal augment placed vertically at the tibiotalar joint. There were no screws or other hardware present to provide compression and stability of the fusion. A computed tomography scan showed a tibiotalar nonunion, erosion of the talar body, and severe tibiotalar and subtalar arthritis. Inflammatory markers were within normal range. Based on the findings of a failed fusion and progressive painful hindfoot deformity, it was determined that the patient would benefit from removal of the hardware and revision fusion surgery. Tibiotalocalcaneal (TTC) hindfoot fusion was planned because of the patient’s talar collapse and tibiotalar/ subtalar arthritis. The TTC procedure was performed with a retrograde intramedullary nail, femoral head allograft, and morselized fibular autograft enriched with platelet-rich plasma. The femoral head was used as a structural allograft to fill the large bone defect, prevent limb shortening, and assist in correction of the hindfoot deformity. Intraoperative findings revealed severe metallic synovitis of the ankle and subtalar joints, metal debris at the site of the trabecular implant, and segmental defects of the distal tibia and talus. Weight bearing was permitted after 16 weeks when evidence of successful ankle fusion was confirmed radiographically. At 24 months, the patient was pain free and ambulating without difficulty.


Antimicrobial Agents and Chemotherapy | 2013

Amphotericin B-Impregnated Bone Cement To Treat Refractory Coccidioidal Osteomyelitis

Elizabeth Zhu; George R. Thompson; Christopher Kreulen; Eric Giza

ABSTRACT Use of amphotericin B-impregnated bone cement in combination with systemic antifungals for the treatment of coccidioidal osteomyelitis offers the potential for sustained local concentrations of drug at the site of the infection. Amphotericin B levels in bone of up to 5.1 μg/g have been demonstrated 4 months after placement of bone cement.


Foot & Ankle International | 2017

Technique for Use of Trabecular Metal Spacers in Tibiotalocalcaneal Arthrodesis With Large Bony Defects.

Christopher Kreulen; Evan Lian; Eric Giza

There are many causes of large bone defects in the tibiotalar joint that need to be definitively treated with a tibiotalocalcaneal (TTC) arthrodesis. Some of the challenges of a large defect are its effect on leg length and the complications associated with trying to fill the defect with structural bone graft. We present an operative strategy involving the use of a trabecular metal implant, a TTC nail that utilized 2 forms of compression, and Reamer/Irrigator/Aspirator (RIA) autograft, to address limitations of previous operative approaches and reliably treat this operative challenge.


Foot and Ankle Specialist | 2018

Seven-Year Follow-up of Matrix-Induced Autologous Implantation in Talus Articular Defects

Christopher Kreulen; Eric Giza; Judie Walton; Martin Sullivan

Background. Osteochondral lesions of the talus (OLT) are difficult to treat because of the poor intrinsic healing capability of articular cartilage. Matrix-induced autologous chondrocyte implantation (MACI) has been shown to be a reliable method for treating cartilage lesions that fail to respond to traditional microfracture and debridement. The purpose of this study was to assess 7-year clinical follow-up data of this technique and demonstrate midterm success of this implant. Methods. A prospective investigation of MACI was performed on 10 patients with OLTs who had failed previous arthroscopic treatment. In all, 5 male and 5 female patients were included in the study. Of the 10 patients, 9 were available for 7-year follow-up. Functional and clinical evaluations were done at 7 years postoperatively using the American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot evaluation and the Short Form Health Survey (SF-36) and compared with preoperative values. Results. SF-36 data at 7 years showed significant improvements in Physical Functioning (P < .01), Lack of Bodily Pain (P < .1), and Social Functioning (P < .001) compared with preoperative data. The mean AOFAS hindfoot scores of the 9 patients at 7 years was 78.3 ± 18.1 (P = .05) compared with their preoperative mean of 61.8 ± 14.3. Conclusions. MACI provides a stable midterm chondral replacement strategy for osteochondral lesions that fail initial microfracture. Levels of Evidence: Level IV: Prospective case series


Archive | 2018

Minimally Invasive Ankle Arthrodesis

Kaitlin C. Neary; Christopher Kreulen; Eric Giza

Ankle arthrodesis has long been the gold standard for end-stage arthritis following failure of non-operative management. For many years, arthrodesis was performed through an open, extensile incision. Although open techniques consistently yield acceptable fusion rates and time to fusion, the risk of skin complications is particularly high in at-risk patients. Recently, minimally invasive ankle risk of soft tissue healing problems, but also to achieve higher fusion rates and decreased time to fusion by reducing soft tissue stripping and preserving the blood supply to the arthrodesis site. Minimally invasive approaches include arthroscopic and mini-open techniques, both of which have demonstrated equivalent, if not better, outcomes when compared to open arthrodesis. These approaches provide an excellent option for patients who are particularly at risk for skin and other soft tissue complications.


Foot & Ankle Orthopaedics | 2018

The Influence of Percentile Weight Bearing on Foot Radiographs

Trevor Shelton; Sohni Singh; Christopher Kreulen; Eric Giza

Category: Midfoot/Forefoot Introduction/Purpose: Clinical decisions are often made based on the measurements of foot radiographs. Orthopaedic patients who have had lower extremity trauma or surgery are often given different weight bearing conditions including non-weight bearing, touch-down weight bearing, partial weight bearing (of various percent of body weight), and weight bearing as tolerated. However, it is largely unknown how these various weight bearing conditions alter specific parameters of foot radiographs. As such, the purpose of this study was to determine whether percent weight bearing influences radiographic measurements of the foot on anteroposterior (AP) and lateral radiographs? Methods: A total of 20 healthy subjects had AP and lateral radiographs of the foot under five weight bearing conditions (non-weight bearing, 10% body weight, 25% body weight, 50% body weight, and 100% body weight). Measurements were then made of hallux valgus angle (HVA), 1-2 intermetatarsal angle (IMA), talonavicular coverage angle (TNCA), talo-calcaneal angle (TCA), forefoot width, LisFranc distance, cuboid height to ground (CHG), and talo-1st metatarsal angle (TMA) of each weight bearing condition. Statistical differences of each measurement for each weight bearing condition were then determined. Measurements were made by a radiologist and orthopaedic surgeon and inter-observer reliability determined for each measurement. For each radiographic measurement, a single factor ANOVA determined whether measurements were different between non-weight bearing, touchdown weight bearing, 25% weight bearing, 50% weight bearing, and 100% weight bearing. When a significant difference was detected, a post-hoc Tukey’s determined which categories of weight bearing were different. Results: The inter-observer reliability determined by the intraclass correlation coefficient was excellent to good in all measurements except for the TCA which was fair. For measurements made on the AP radiographs of the foot, the measurements that changed with percent weight bearing were the TNCA (p = 0.0009) and TCA (p = 0.0446) (Table 1). Weight bearing did not change the HVA (p = 0.2564, IMA (p = 0.1698), forefoot width (p = 0.2431), or LisFranc distance (p = 0.9854). For measurements made on the lateral radiographs of the foot, the measurement that changed with percent weight bearing was the CHG (p = 0.006). Weight bearing did not change the TMA (p = 0.9889). Conclusion: This study demonstrates a flattening of the medial arch with increasing percent body weight applied to a foot. This results in an increase in the TNCA as well as a decrease in the CHG. In addition, increasing percent body weight to the foot increases the hindfoot alignment. However, percent body weight does not alter measurements of the forefoot. Percentage body weight increase may not influence clinical preoperative/non-operative treatment as much as we expect; however, our findings do show that certain parameters increase with increasing weight bearing.


Foot & Ankle Orthopaedics | 2018

Treatment of osteochondral lesions in the ankle with a particulated juvenile cartilage allograft: five year outcomes in a challenging clinic population

Karim Boukhemis; Christopher Kreulen; J. Chris Coetzee; Steven Neufeld; Gregory C. Berlet; Thomas Dowd; Paul Ryan; Justin Robbins; Eric Giza

Category: Ankle Introduction/Purpose: Numerous treatment modalities are in use today to treat symptomatic osteochondral lesions in the ankle; however, there are ongoing challenges with the treatment of certain types of lesions and concern regarding the long-term effectiveness of current common techniques. Methods: The purpose of this study was to collect mid and long-term clinical outcomes of pain, function, and activity level (VAS, SF-12, FAAM ADL, FAAM sports) Single-arm, multi-center study collected outcomes prospectively in standard clinic patients who would be undergoing or who had previously undergone treatment with DeNovo NT. The main exclusion criteria were high surgical risk, clinically diagnosed autoimmune diseases, or an active joint infection; all other patients receiving DeNovo NT could be approached for the study. The outcome analysis for this abstract focused on enrolled subjects’ final follow-up to date. Results: Clinical outcomes have been prospectively collected for 24 subjects with a total of 48 months follow-up. Twenty four of the treated lesions were located on the talus, none on the tibia. Out of the 24 patients, 23 had a single lesion and 1 had more than one. The average lesion size was 108.1 mm +/- 60.0 [23]. The Hepple classification was used to categorize each lesion. Interestingly, 19/24 were classified as 3 or higher. Cartilage ICRS was also used for classification. Out of the subjects, 23/24 were ICRS grade 3 or 4. There was also a concomitant procedure for 22/24 patients. Pre and post op VAS scores of 47.5 (+/- 23.1) and 12.2 +/- 17.8. SF-12 scores pre and post of 38.0 +/- 8.5 and 50.1 +/- 8.2. FAAM ADL’s pre and post 60.4 +/- 16.3 and 90.4 +/-11.8. FAAM sport scale scores pre and post 28.8 +/- 16.7 and 74.5 +/- 22.4. all outcome measures were statistically significant. Conclusion: Four year complete data is a challenge in this particular clinical population. This data set encompasses symptomatic osteochondral lesions of the talus treated with particulated juvenile cartilage allograft. The outcomes reflect an improvement in symptoms and patient satisfaction when treated with this technique. Based on these final outcome measures (V AS, SF-12, FAAM ADL’s, FAAM sport scale score) and satisfaction, it can be concluded that this is a viable option to get patients back to their pre-injury state.

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Eric Giza

University of California

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Brent Roster

University of California

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Connor Delman

University of California

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Connor Nathe

University of California

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Sohni Singh

University of California

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Alan L. Zhang

University of California

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Alvin Shieh

University of California

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Annahita Sarcon

University of Southern California

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