Myositis ossificans

Myositis ossificans (MO) and fibro-osseous pseudotumour of digits are localised self-limiting lesions composed of reactive hypercellular fibrous tissue and bone (1). They often grow rapidly and biopsy may reveal mitotic activity and hypercellularity, and they are therefore classic pseudosarcomas.

These conditions can occur throughout life, but are most common in young adulthood (mean age 32 years). Males are more frequently affected than females (3:2), although FP more commonly occurs in females.

Soft tissue injury is the most common initiating event. MO can develop anywhere in the body but is most common in areas which are readily injured, such as the extremities, thigh, buttock and shoulder. It usually develops in skeletal muscle. Similar lesions occur in the subcutaneous tissue (panniculitis ossificans), tendons or fascia (fasciitis ossificans).

Early in the development of the lesion, there is classically swelling and pain. Calcification appears after 2-6 weeks, often in an eggshell like-distribution (hence the synonym myositis ossificans circumscripta). Over time, lesions become hard and well demarcated.

Lesions range in size from 2 to 12cm with a mean of around 5cm. Macroscopically they have a gritty white periphery and a soft tan haemorrhagic centre. On microscopy, early lesions appear highly cellular, comprising proliferating fibroblasts. There can be well-formed bony trabeculae peripherally.

Treatment is usually expectant with anti-inflammatory medication. Lesions can be removed after they have matured. Recurrence is unusual. The use of bisphosphonates has been described (2).


1. WHO Classification of tumours of soft tissue and bone. 4th Edition. 2013

2. Mani-Babu S et al. Quadriceps traumatic myositis ossificans in a football player: management with intravenous pamidronate. Clin J Sport Med. 2014 Sep;24(5):e56-8



Sacrectomy is a challenging surgical procedure used in the treatment of primary tumours of the sacrum (eg chordoma) or rectal tumours (usually locally recurrent) involving the sacrum. The complexity and disability associated with the procedure depends in large part on the level of resection. High sacral resections can lead to loss of bladder and bowel function (1).

The procedure can be performed through a combined abdomino-lateral approach, sequential abdominal then posterior approaches or entirely by a posterior approach depending on the local extent of the tumour and involvement of critical anatomical structures. Division of the bone just below the lower border of S3 preserves sphincteric function. Bilateral sacrifice of S2-S4 roots lead to urinary and faecal incontinence and male impotence. Anorectal incontinence can be preserved if one S2 root is maintained.

The dural sac ends at the S2/3 junction, and if entered, requires meticulous closure. For higher sacral resections the posterior sacral plate is removed with rongeurs, which may allow identification of sacral nerve roots. Attempts should be made to spare the pudendal nerve if it is encountered running posterior to the ischial spine.

Sacrectomy requires specialist expertise and a team which includes colorectal, orthopaedic and plastic surgical expertise as appropriate. After resection of the sacrum, reconstruction of the soft tissue defect may be achieved using a VRAM rectus abdominis pedicled flap or IGAP gluteal muscle transfers.

For more information, the chapter on sacrectomy in Malawer’s book is very helpful (
1. Spine J. 2015 Feb 1;15(2):222-9. Maintenance of bowel, bladder, and motor functions after sacrectomy. Moran D, Zadnik PL, Taylor T, Groves ML, Yurter A, Wolinsky JP, Witham TF, Bydon A, Gokaslan ZL, Sciubba DM.

Classic papers in Orthopaedic Oncology

We recently scratched our heads and put a list of classic orthopaedic oncology papers together for this book:

We were looking for papers that made an impact on the specialty or inform daily practice, as well as those which are cited widely. The list we came up with was:


CADE, S. (1955). Osteogenic sarcoma; a study based on 133 patients. Journal of the Royal College of Surgeons of Edinburgh, 1(2), 79–111. Retrieved from
Codman, E. A. (2009). The classic: the registry of bone sarcomas as an example of the end-result idea in hospital organization. 1924. Clinical Orthopaedics and Related Research, 467(11), 2766–70. doi:10.1007/s11999-009-1048-7
Dahlin, D. C., & Coventry, M. B. (1967). Osteogenic sarcoma. A study of six hundred cases. The Journal of Bone and Joint Surgery. American Volume, 49(1), 101–10. Retrieved from
Enneking, W. F., Dunham, W., Gebhardt, M. C., Malawar, M., & Pritchard, D. J. (1993). A system for the functional evaluation of reconstructive procedures after surgical treatment of tumors of the musculoskeletal system. Clinical Orthopaedics and Related Research, (286), 241–6. Retrieved from
Enneking, W. F., Spanier, S. S., & Goodman, M. A. (2003). A system for the surgical staging of musculoskeletal sarcoma. Clinical Orthopaedics and Related Research, (153), 106–20. Retrieved from
Mankin, H. J., Lange, T. A., & Spanier, S. S. (1982). The hazards of biopsy in patients with malignant primary bone and soft-tissue tumors. The Journal of Bone and Joint Surgery. American Volume, 64(8), 1121–7. Retrieved from
Mirels, H. (1989). Metastatic disease in long bones. A proposed scoring system for diagnosing impending pathologic fractures. Clinical Orthopaedics and Related Research, (249), 256–64. Retrieved from
O’Sullivan, B., Davis, A. M., Turcotte, R., Bell, R., Catton, C., Chabot, P., … Zee, B. (2002). Preoperative versus postoperative radiotherapy in soft-tissue sarcoma of the limbs: a randomised trial. Lancet, 359(9325), 2235–41. doi:10.1016/S0140-6736(02)09292-9
Rosen, G., Murphy, M. L., Huvos, A. G., Gutierrez, M., & Marcove, R. C. (1976). Chemotherapy, en bloc resection, and prosthetic bone replacement in the treatment of osteogenic sarcoma. Cancer, 37(1), 1–11. Retrieved from
Rosenberg, S. A., Tepper, J., Glatstein, E., Costa, J., Baker, A., Brennan, M., … Wesley, R. (1982). The Treatment of Soft-tissue Sarcomas of the Extremities. Prospective Randomized Evaluations of (1) Limb-sparing Surgery Plus Radiation Therapy Compared with Amputation and (2) the Role of Adjuvant Chemotherapy. Annals of Surgery, 196(3), 305–315. Retrieved from

What’s missing? Your comments welcomed.