Clinical Focus

  • Orthopaedic Surgery
  • Sarcomas

Academic Appointments

Administrative Appointments

  • Chief, Musculoskeletal Tumor Service (2005 - Present)

Honors & Awards

  • Alpha Omega Alpha, Honor Medical Society (1983)
  • National Research Service Award, NIH (1987)
  • Saul Halpern, MD Orthopaedic Educator Award, Surgery Stanford University School of Medicine (2007)

Professional Education

  • Internship:UCLA David Geffen School Of Medicine Registrar (1984) CA
  • Medical Education:Weill Cornell School of Medicine (1983) NY
  • Fellowship:Memorial Sloan-Kettering Cancer Center (1989) NY
  • Residency:Hospital For Special Surgery (1988) NY
  • Board Certification: Orthopaedic Surgery, American Board of Orthopaedic Surgery (1991)
  • MD, Memorial Sloan-Kettering, Bone Disease/Bone Tumor (1989)
  • MD, Hospital for Special Surgery, Orthopaedic Surgery (1988)
  • MD, UCLA, General Surgery (1984)
  • MD, Cornell Univ. Medical College, Medicine (1983)

Research & Scholarship

Current Research and Scholarly Interests

Dr. Mohler is involved in gene expression in sarcomas, and innovative anatomy-preserving surgical management of low grade chondrosarcomas.


2018-19 Courses


All Publications

  • Genome-Informed Targeted Therapy for Osteosarcoma. Cancer discovery Sayles, L. C., Breese, M. R., Koehne, A. L., Leung, S. G., Lee, A. G., Liu, H., Spillinger, A., Shah, A. T., Tanasa, B., Straessler, K., Hazard, F. K., Spunt, S. L., Marina, N., Kim, G. E., Cho, S., Avedian, R. S., Mohler, D. G., Kim, M., Dubois, S. G., Hawkins, D. S., Sweet-Cordero, E. A. 2018


    Osteosarcoma (OS) is a highly aggressive cancer for which treatment has remained essentially unchanged for over 30 years. OS is characterized by widespread and recurrent somatic copy-number alterations (SCNAs) and structural rearrangements. In contrast, few recurrent point mutations in protein-coding genes have been identified, suggesting that genes within SCNAs are key oncogenic drivers in this disease. SCNAs and structural rearrangements are highly heterogeneous across OS cases, suggesting the need for a genome-informed approach to targeted therapy. To identify patient-specific candidate drivers, we used a simple heuristic based on degree and rank order of copy number amplification (identified by Whole Genome Sequencing) and changes in gene expression as identified by RNAseq. Using patient-derived tumor xenografts, we demonstrate that targeting of patient-specific somatic copy number alterations leads to significant decrease in tumor burden, providing a roadmap for genome-informed treatment of OS.

    View details for DOI 10.1158/2159-8290.CD-17-1152

    View details for PubMedID 30266815

  • Cervical erector spinae plane block catheter using a thoracic approach: an alternative to brachial plexus blockade for forequarter amputation. Canadian journal of anaesthesia = Journal canadien d'anesthesie Tsui, B. C., Mohler, D., Caruso, T. J., Horn, J. L. 2018

    View details for DOI 10.1007/s12630-018-1170-7

    View details for PubMedID 29868941

  • Oncologic and Functional Results of Curettage and Cryosurgical Treatment of Low Grade Chondrosarcomas Clinical Orthopaedics and Related Research. (Accepted 10/2009) Mohler, D.G.,, Chiu, R, McCall, DA, Avedian, RS
  • Extraskeletal osteosarcoma of the hand: the role of marginal excision and adjuvant radiation therapy. Hand (New York, N.Y.) Casey, D. L., van de Rijn, M., Riley, G., Tung, K., Mohler, D. G., Donaldson, S. S. 2015; 10 (4): 602-606


    Extraskeletal osteosarcoma of the hand is rare, and its optimal modality of local control is not currently known.A literature search was performed to identify studies that describe the treatment and outcomes of extraskeletal osteosarcoma. A second literature search was performed to identify studies that describe the treatment and outcomes of extraskeletal osteosarcoma of the hand specifically.The role of adjuvant radiation for extraskeletal osteosarcoma is not well defined. All cases in the literature describing treatment of extraskeletal osteosarcoma of the hand utilized amputation, and none of the patients described received radiation therapy. However, there are multiple reports showing excellent local control, minimal toxicity, and superior functional outcome with limb conservation and radiation rather than amputation of the hand in pediatric and adult soft tissue sarcoma.For extraskeletal osteosarcoma of the hand, we recommend a treatment approach with the goal of preservation of form and function using limb-sparing surgery and planned postoperative radiation.

    View details for DOI 10.1007/s11552-015-9760-0

    View details for PubMedID 26568711

    View details for PubMedCentralID PMC4641083

  • Sarcoma Resection With and Without Vascular Reconstruction: A Matched Case-control Study ANNALS OF SURGERY Poultsides, G. A., Tran, T. B., Zambrano, E., Janson, L., Mohler, D. G., Mell, M. W., Avedian, R. S., Visser, B. C., Lee, J. T., Ganjoo, K., Harris, E. J., Norton, J. A. 2015; 262 (4): 632-640


    To examine the impact of major vascular resection on sarcoma resection outcomes.En bloc resection and reconstruction of involved vessels is being increasingly performed during sarcoma surgery; however, the perioperative and oncologic outcomes of this strategy are not well described.Patients undergoing sarcoma resection with (VASC) and without (NO-VASC) vascular reconstruction were 1:2 matched on anatomic site, histology, grade, size, synchronous metastasis, and primary (vs. repeat) resection. R2 resections were excluded. Endpoints included perioperative morbidity, mortality, local recurrence, and survival.From 2000 to 2014, 50 sarcoma patients underwent VASC resection. These were matched with 100 NO-VASC patients having similar clinicopathologic characteristics. The rates of any complication (74% vs. 44%, P = 0.002), grade 3 or higher complication (38% vs. 18%, P = 0.024), and transfusion (66% vs. 33%, P < 0.001) were all more common in the VASC group. Thirty-day (2% vs. 0%, P = 0.30) or 90-day mortality (6% vs. 2%, P = 0.24) were not significantly higher. Local recurrence (5-year, 51% vs. 54%, P = 0.11) and overall survival after resection (5-year, 59% vs. 53%, P = 0.67) were similar between the 2 groups. Within the VASC group, overall survival was not affected by the type of vessel involved (artery vs. vein) or the presence of histology-proven vessel wall invasion.Vascular resection and reconstruction during sarcoma resection significantly increases perioperative morbidity and requires meticulous preoperative multidisciplinary planning. However, the oncologic outcome appears equivalent to cases without major vascular involvement. The anticipated need for vascular resection and reconstruction should not be a contraindication to sarcoma resection.

    View details for DOI 10.1097/SLA.0000000000001455

    View details for Web of Science ID 000367999800009

  • Antirotation Pins Improve Stability of the Compress Limb Salvage Implant: A Biomechanical Study CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Avedian, R. S., Chen, T., Lindsey, D., Palanca, A., Mohler, D. 2014; 472 (12): 3982-3986


    Limb salvage implants that rely on compliant compression osseointegration to achieve bone fixation may achieve longer survivorship rates compared with traditional cemented or press-fit stemmed implants; however, failures resulting from rotational instability have been reported. The effect of using antirotation pins on the rotational stability of the fixation has not been well studied.We asked the following question: When tested in a cadaver model, does the use of antirotation pins increase the torque required to cause implant failure or rotation?Thirty-two cadaver femurs were divided into four groups of eight femurs. We compared the torque to failure among groups containing zero, one, two, three, and four pins using a servohydraulic testing device.Adding antirotation pins increased the torque required to cause failure (R(2) = 0.77; p < 0.001). This increase was most notable in groups comparing zero pins with one pin (14 N-m, [95% CI, 10.9-17.1] versus 23 N-m, [95% CI 22.5-23.48]; p = 0.01) and two compared with three pins (29 N-m, [95% CI, 21.7-36.3] versus 42 N-m, [95% CI, 37.8-46.2]; p = 0.35).It appears that the use of antirotation pins improves rotational stability of the compliant compression endoprosthesis. Although these findings need to be verified in a clinical study, the addition of antirotation pins may improve osteointegration and we have changed our practice to use a minimum of three antirotation pins when implanting this device.Improvements in implant technology and surgical techniques may lead to improved clinical outcomes and patient quality of life. Addition of antirotation pins appears to improve implant stability and may decrease the need for revision surgery.

    View details for DOI 10.1007/s11999-014-3899-9

    View details for Web of Science ID 000344647200052

    View details for PubMedCentralID PMC4397809

  • Surgical Technique: Methods for Removing a Compress (R) Compliant Prestress Implant CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Abrams, G. D., Gajendran, V. K., Mohler, D. G., Avedian, R. S. 2012; 470 (4): 1204-1212


    The Compress® device uses a unique design using compressive forces to achieve bone ingrowth on the prosthesis. Because of its design, removal of this device may require special techniques to preserve host bone. DESCRIPTION OF TECHNIQUES: Techniques needed include removal of a small amount of bone to relieve compressive forces, use of a pin extractor and/or Kirschner wires for removal of transfixation pins, and creation of a cortical window in the diaphysis to gain access to bone preventing removal of the anchor plug.We retrospectively reviewed the records of 63 patients receiving a Compress® device from 1996 to 2011 and identified 11 patients who underwent subsequent prosthesis removal. The minimum followup was 1 month (average, 20 months; range, 1-80 months). The most common reason for removal was infection (eight patients) and the most common underlying diagnosis was osteosarcoma (five patients). Three patients underwent above-knee amputation, whereas the others (eight patients) had further limb salvage procedures at the time of prosthesis removal.Five patients had additional unplanned surgeries after explantation. Irrigation and débridement of the surgical wound was the most common unplanned procedure followed by latissimus free flap and hip prosthesis dislocation. At the time of followup, all patients were ambulating on either salvaged extremities or prostheses.Although removal of the Compress® device presents unique challenges, we describe techniques to address those challenges.

    View details for DOI 10.1007/s11999-011-2128-z

    View details for Web of Science ID 000301442800032

    View details for PubMedID 22002827

    View details for PubMedCentralID PMC3293961

  • Curettage and Cryosurgery for Low-grade Cartilage Tumors Is Associated with Low Recurrence and High Function CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Mohler, D. G., Chiu, R., McCall, D. A., Avedian, R. S. 2010; 468 (10): 2765-2773


    Chondrosarcomas of bone traditionally have been treated by wide or radical excision, procedures that may result in considerable lifelong disability. Grade 1 chondrosarcomas have little or no metastatic potential and are often difficult to distinguish from painful benign enchondromas. Curettage with adjuvant cryosurgery has been proposed as an alternative therapy for Grade 1 chondrosarcomas given the generally better function after the procedure. However, because it is an intralesional procedure, curettage and cryosurgery may be associated with higher rates of recurrence.We asked whether Grade 1 chondrosarcomas and enchondromas of uncertain malignant potential treated by curettage and cryosurgery are associated with low recurrence rates and high functional scores.We retrospectively reviewed the records of 46 patients with Grade 1 chondrosarcomas and enchondromas of uncertain malignant potential treated by curettage and cryosurgery. Forty-one patients had tumors of the long bones. Patients were followed a minimum of 18 months (average, 47.2. months; range, 18-134 months) for evidence of recurrence and for assessment of Musculoskeletal Tumor Society (MSTS) functional score.Two of the 46 patients had recurrences in the original tumor site (4.3% recurrence rate), which subsequently were removed by wide excision, and both patients were confirmed to be disease-free 36 and 30 months, respectively, after the second surgery. The mean MSTS score was 27.2 of 30 points (median, 29 points).Our observations show curettage with cryosurgery is associated with low recurrence of Grade 1 chondrosarcoma and high functional scores. Curettage with cryosurgery is a reasonable alternative to wide or radical excision as the treatment for Grade 1 chondrosarcomas, and allows for more radical surgery in the event of local recurrence.Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

    View details for DOI 10.1007/s11999-010-1445-y

    View details for Web of Science ID 000281843200028

    View details for PubMedID 20574801

    View details for PubMedCentralID PMC3049634



    Pigmented villonodular synovitis (PVNS) is a rare proliferative disorder of the synovium with locally aggressive behavior. We reviewed our experience using radiation therapy in the treatment of PVNS.Seventeen patients with 18 sites of PVNS were treated with radiation between 1993 and 2007. Cases were retrospectively reviewed for patient information, treatment parameters, complications, and outcome. Seven sites were primary presentations and 11 were recurrent with an average of 2.5 prior surgical interventions. The most common location was the knee joint (67%). Cytoreductive surgery was performed before radiation therapy in 16/18 sites with all having proven or suspected residual disease. Radiation was delivered using 4-15 MV photons with an average total dose 34 Gy (range, 20-36 Gy). Seventeen of 18 sites (94%) had postradiotherapy imaging.With average follow-up of 46 months (range, 8-181 months), initial local control was achieved in 75% (12/16) of the sites with prior cytoreductive surgery (mean time to recurrence, 38 months). Ultimate local control was 100% after repeat resection (mean follow-up, 61 months). Two additional sites without prior cytoreductive surgery showed growth after radiotherapy (mean time to documented growth, 10.5 months). Seventeen of the 18 involved joints (94%) were scored as excellent or good PVNS-related function, one site (5%) as fair function, and no site with poor function. No patient required amputation; and there were no Grade 3/4 treatment-related complications.Postoperative external beam radiation is effective in preventing disease recurrence and should be offered following maximal cytoreduction to enhance local control in PVNS.

    View details for DOI 10.1016/j.ijrobp.2008.10.058

    View details for Web of Science ID 000269328700031

    View details for PubMedID 19211195

  • Hunting Injuries In Wilderness Medicine, Editor Auerbach, P. Elsevier Press Mohler, D., Otes, D 2007
  • Failure of medullary tubes - A materials analysis INJURY-INTERNATIONAL JOURNAL OF THE CARE OF THE INJURED Taub, M., Wera, G., Dauskardt, R. H., Mohler, D. G. 2004; 35 (9): 878-882


    The objective of this study is to determine the effects of autoclaving on the stress, strain, ultimate tensile strength (UTS), fracture strain, modulus, and yield stress of nylon medullary tubes. There are three reports describing nylon medullary tube failure in the literature. All cases involved the use of nylon medullary tubes during open reduction internal fixation of fractured long bones. We demonstrated increased brittleness and decreased strength with increased exposure of medullary tubes to autoclaving, most dramatically after 100 autoclave cycles. Visual inspection of tubes is a clear indication of material degradation after repeated autoclaving. Furthermore, there is a significant difference in ultimate tensile strength (P < 0.0001) between tubes exposed to less than 100 sterilization cycles compared to tubes exposed to greater than 100 cycles. Likewise, there is a significant decrease in yield stress (P < 0.0004) between the same groups. We recommend disposal and replacement of nylon medullary tubes before they are exposed to 100 autoclaving cycles in order to avoid failure of the device.

    View details for DOI 10.1016/S0020-1383(03)00307-3

    View details for Web of Science ID 000223692100007

    View details for PubMedID 15302240

  • Intercalary tibial allografts following tumor resection: The role of fibular centralization ORTHOPEDICS Mohler, D. G., Yaszay, B., Hong, R., Wera, G. 2003; 26 (6): 631-637


    Options to reconstruct intercalary tibial defects include allografts, vascularized bone transfers, autogenous cortical grafts, endoprostheses, and Ilizarov bone transport. Five patients underwent intercalary bulk allograft reconstruction following en bloc resection of tibial sarcomas. Two patients underwent immediate fibular centralization and iliac crest bone grafting in addition to the allograft. Two patients who underwent fibular centralization during primary reconstruction united uneventfully. The remaining three patients developed nonunion, of which one was successfully salvaged by fibular centralization. A combined allograft transplant and fibular centralization with iliac crest bone grafting is an effective procedure to reconstruct the tibial diaphysis, as well as a salvage procedure for allograft nonunion.

    View details for Web of Science ID 000183456200007

    View details for PubMedID 12817729

  • Multifocal pseudoaneurysmal bone cysts in sickle cell disease ORTHOPEDICS Kim, S. S., Fernando, T. L., Mohler, D. G. 2001; 24 (5): 489-491

    View details for Web of Science ID 000168761800015

    View details for PubMedID 11379999

  • Multiple fracture of medullary tube during intramedullary nailing of long bone fractures JOURNAL OF ORTHOPAEDIC TRAUMA Vakharia, M. R., Lehto, S. A., Mohler, D. G. 2000; 14 (7): 514-517


    Intramedullary nailing is an accepted treatment for the fixation of femoral and tibial shaft fractures. There is a low but significant incidence of intraoperative complications during intramedullary nailing. During this procedure, a medullary tube may be used to exchange the bent olive-tipped reaming guidewire for the straight guidewire. A review of the literature found only one report of a fracture of the medullary tube. Two cases in which the medullary tube fractured into multiple pieces are presented.

    View details for Web of Science ID 000165097300011

    View details for PubMedID 11083617

  • Augmented amputations of the lower extremity CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Mohler, D. G., Kessler, J. I., Earp, B. E. 2000: 183-197


    Ten patients who had amputations of a lower extremity for high-grade sarcomas underwent bone augmentation with either allograft or autograft between 1988 and 1996. There were eight transfemoral amputations and two transtibial amputations. The transferred segments consisted of one proximal tibia and six distal tibia autografts, two allografts, one autograft talar dome and first metatarsal, and one with a patellar cap of a supracondylar amputation. The average length of followup was 54 months. There were no nonunions of any of the grafts. There were three wound problems requiring additional operations. One autograft resorbed, and one autograft had a late infection. There was one local recurrence. Augmentation to provide length resulted in a 42% increase in bone length in those performed purely for length. All patients were able to use standard prostheses. Functional outcome was appropriate to the amputation level. Half of the patients avoided more proximal levels of amputation because of the ability to augment the osteotomy. The use of nonvascularized structural autografts or allografts is a simple procedure that can produce a superior residual limb in patients undergoing amputation. Its use should be considered in patients for whom traditional amputation techniques will result in poor function, difficulty in fitting a prosthesis, or greater than necessary anatomic loss.

    View details for Web of Science ID 000085397700024

    View details for PubMedID 10693566

  • Open synovectomy with cryosurgical adjuvant for treatment of diffuse pigmented villonodular synovitis of the knee. Bulletin (Hospital for Joint Diseases (New York, N.Y.)) Mohler, D. G., Kessler, B. D. 2000; 59 (2): 99-105


    Pigmented villonodular synovitis (PVNS) is an uncommon, benign disorder usually affecting the synovial membrane of large joints. The diffuse form of PVNS is extremely difficult to control, and long-term recurrence inevitably results in arthrodesis or arthroplasty. Current treatments include surgical, chemical, and radiation synovectomy, but all have significant failure rates. In hope of obtaining a more complete synovectomy, we used cryosurgery as an adjuvant to open synovectomy in three patients. Two patients presented with multiple failed arthroscopic synovectomies, and one patient presented with arthroscopically unresectable PVNS. The surgical approach involved take down and repair of the anterior meniscal attachments, and direct entry into the posterior space through medial and lateral femoral capsular attachments. Cryosurgical surface spray was used on all non-cartilaginous surfaces. At follow-up of 14, 30, and 31 months, all three patients remained symptom-free and there were no indications of clinical recurrence. There were no obvious complications or morbidity from the cryosurgical procedure and all patients had excellent functional recovery. All patients returned to sports and their jobs without restrictions. In the past, it has been shown that cryosurgery is a safe and effective treatment modality for proliferative joint disease. We propose the use of adjuvant cryosurgery for PVNS patients selected for open synovectomy.

    View details for PubMedID 10983259

  • Complete pelvic ring failure after posterior iliac bone graft harvesting SPINE Fernando, T. L., Kim, S. S., Mohler, D. G. 1999; 24 (20): 2101-2104


    Case report.To present a rare complication of posterior iliac bone graft harvesting.Although iliac bone graft harvesting is a common procedure in spinal surgery, it is not without complications. One such complication is fracture of the ilium that is seen most often in older women with osteopenia.In this case a severe complication of posterior iliac bone graft harvesting was identified in a patient with steroid-induced osteoporosis that led to multiple pelvic fracture, nonunions, and eventual failure of the entire pelvic ring. Imaging studies showed osteoporotic bone and multiple nonunions of the pelvis with structural collapse.Staged sequential platings of the iliac wings were performed to stabilize the pelvis. The initial fixation of the left iliac wing apparently united after hardware failure. The right iliac wing was successfully fixed with plates supplemented with bone cement and allograft. Anterior fixation was planned.Care should be taken when considering autograft harvesting in patients with risk factors for osteoporosis. The outcome could be debilitating.

    View details for Web of Science ID 000083124400006

    View details for PubMedID 10543005

  • Angiosarcoma of the hand associated with chronic exposure to polyvinyl chloride pipes and cement. A case report. journal of bone and joint surgery. American volume Mohler, D. G., Chen, W. W., Bloom, H. 1998; 80 (9): 1349-1354

    View details for PubMedID 9759821

  • Angiosarcoma of the hand associated with chronic exposure to polyvinyl chloride pipes and cement - A case report JOURNAL OF BONE AND JOINT SURGERY-AMERICAN VOLUME Mohler, D. G., Chen, W. W., Bloom, H. 1998; 80A (9): 1349-1354
  • Adamantinoma arising in the distal fibula treated with distal fibulectomy: A case report and review of the literature FOOT & ANKLE INTERNATIONAL Mohler, D. G., Cunningham, D. C. 1997; 18 (11): 746-751


    Adamantinoma is a rare primary bone tumor occurring in the mandible and the long tubular bones. The diaphysis of the tibia is the most common site of extragnathic presentation. Fibular involvement is rare and usually has coexisting tibial involvement. Adamantinoma arising in the distal fibular metaphysis has not been previously reported. This is a case of a teenage boy presenting with a cystic lesion of the distal fibula, initially diagnosed and treated as a unicameral bone cyst. Aggressive behavior ultimately led to a diagnosis of adamantinoma. He was treated with distal fibulectomy without surgical reconstruction with good functional outcome.

    View details for Web of Science ID A1997YF98100012

    View details for PubMedID 9391822

  • Glomus tumor of the plantar arch: A case report with magnetic resonance imaging findings FOOT & ANKLE INTERNATIONAL Mohler, D. G., Lim, C. K., Martin, B. 1997; 18 (10): 672-674


    A 55-year-old woman with a 12-year history of a painful nodule in the subcutaneous fat layer of the plantar arch was evaluated with magnetic resonance imaging, followed by excisional biopsy. Pathology revealed a glomus tumor, which is extremely rare in the plantar surface of the foot. The magnetic resonance imaging studies are presented. The literature on glomus tumors in the foot is reviewed. This entity should be considered in the differential diagnosis of solitary plantar nodules when marked sensitivity to temperature or pressure is exhibited.

    View details for Web of Science ID A1997YB59300014

    View details for PubMedID 9347308