Consultant Orthopaedic Surgeon

Tom Cosker: Medicolegal Expert

Tom Cosker has extensive experience in medicolegal practice and works with a number of medical agencies, including Premex, Premier Medical, UK Independent Medical (UKIM), Mobile Doctors, IQED and a number of personal injury solicitors, including Lupton Fawcett.

Tom looks forward to continuing to act as an expert witness for these medical agencies and future conference opportunities. This is a rapidly evolving marketplace and it is essential for those involved to provide the best possible reporting and expert evidence.


Medical Negligence Expert

Tom Cosker is an expert witness specialising in Orthopaedic Oncology. This includes a variety of conditions including primary bone tumours or primary bone cancers such as Osteosarcoma, Chondrosarcoma, Giant Cell Tumour of Bone and other less common conditions such as osteoid osteoma as well as soft tissue tumours such as soft tissue sarcoma and metastatic disease. For such cases in orthopaedic oncology prompt diagnosis and treatment is essential because there is a direct correlation between prompt diagnosis and improved survival.

Unfortunately, in many cases that Tom encounters, there has been a delayed diagnosis leading to either the need for amputation of a limb or even shortened survival. Tom’s day to day practice specialises in treating these kind of orthopaedic oncology problems and so he is in a perfect position to assist the Court in preparation of expert evidence to assist Claimant’s and Defendant’s with their cases.

Tom Cosker provides a rapid service and works closely with instructing parties to ensure that evidence is prepared in a timely manner. He is able to provide a full review of the medical records to include the salient entries for the case and ensure that all aspects of the orthopaedic oncology case are properly covered.


The early signs of osteosarcoma are usually caught on X-rays. A biopsy of suspected osteosarcoma outside of the facial region should be performed by a qualified orthopaedic oncologist such as Mr Cosker. The American Cancer Society states: “Probably in no other cancer is it as important to perform this procedure properly. An improperly performed biopsy may make it difficult to save the affected limb from amputation.” It may also metastasise to the lungs, mainly appearing on the chest X-ray as solitary or multiple round nodules most common at the lower regions.

Tom has significant experience in dealing with such cases from a medicolegal perspective and is able to comment on (un)reasonable delays and timing of surgery.

Family General Practitioners and General Orthopaedic Surgeons rarely see a malignant bone tumour (most bone tumours are benign). The pathway to osteosarcoma diagnosis usually begins with an X-ray, continues with a combination of scans (CT scan, PET scan, bone scan, MRI) and ends with a surgical biopsy.

A feature often seen by an orthopaedic oncology surgeon like Tom Cosker in an X-ray is Codman’s triangle, which is a subperiosteal lesion formed when the periosteum is raised due to the tumour. Films are suggestive, but bone biopsy is the only definitive method to determine whether a tumour is malignant or benign. Tom is experienced in the diagnosis of such malignant bone tumours.


Prognosis of primary bone tumours such as osteosarcoma is separated into three groups.

Stage I osteosarcoma is rare and includes parosteal osteosarcoma or low-grade central osteosarcoma. It has an excellent prognosis (>90%) with wide resection. Stage II prognosis depends on the site of the tumour (proximal tibia, femur, pelvis, etc.), size of the tumor mass, and the degree of necrosis having given neoadjuvant chemotherapy. Tom comments that with a longer length of time (more than 24 months) and few nodules (two or fewer) patients have the best prognosis, with a two-year survival after the metastases of 50%, five-year of 40%, and 10-year of 20%. If metastases are both local and regional, the prognosis is worse. 

Initial prognosis of stage III osteosarcoma with lung metastases depends on the resectability of the primary tumour and lung nodules, degree of necrosis of the primary tumour, and the number of metastases. Overall survival prognosis at five years is about 30%.

Medicolegal Consultant

Tom Cosker was one of the guest speakers invited to lecture at the Premex Services National Conference in 2018 and 2019 along with fellow surgeon Sherief Elsayed.

Attended by 150 delegates including GPs, orthopaedic surgeons, neurosurgeons, plastic surgeons and Premex staff, this year’s conference was the biggest yet for Premex Services and gave a detailed insight into the constantly evolving medico-legal marketplace.