Introduction: Anterior Knee pain is a very common presentation in Orthopaedic out patient clinics. However, Trochlear Dysplasia as a condition is still not very well understood.

Materials and Methods: Operative findings in patients undergoing Trochleaplasty and in young patients undergoing Patella-femoral arthroplasty were studied. Patients having trochlear dysplasia were identified. All these patients were sent a questionnaire to explore the variety of symptoms they experienced. 87 patients were identified for the study. 71(82%) patients responded to the questionnaire.

Results: Two subgroups were identified, one with dislocation of patella and the other without dislocation of the patella. Patients in patella dislocation group were younger (12 years vs 24) than those who presented without dislocation of patella. Patella dislocation group had more patients with anterior knee pain (71% vs 52%) as teenagers as compared to the group without dislocations. Symptoms such as giving way, lack of trust and unable to participate in sports were more commonly seen in the group with patella dislocation whereas, limited walking distance and difficulty with climbing the stairs were more commonly seen in the group without dislocation. Symptoms such as pain, catching and locking were seen equally amongst the two groups.

Conclusion: We believe that the patients with trochlear dysplasia have a bimodal presentation. Patients with dislocation of patella present earlier than those without patella dislocation. These two groups also have different symptoms at presentation. It is important to identify these subgroups correctly for appropriate management.

We report our clinical experience with three patients in whom squamous cell carcinomas developed secondarily to chronic bone infections. The diagnosis was delayed in each case.

There are several well recognised warning signs which should alert the physician to the possibility of malignant change having occurred in the region of chronic bony infection.

Close attention to these signs will prevent undue delay in diagnosis and avoid the associated complications.

As chronic osteomyelitis becomes less common in first world countries we need to remain aware of the possible complications which can be encountered.

The diagnosis in each of our cases was delayed by the fact that the possibility of malignant change was not considered by several experienced orthopaedic surgeons.

When there is change in signs and symptoms or altered flora within the discharge one must be alerted to the possibility of malignant change. This should prevent delays in diagnosis. Radiological progression should probably be regarded as malignant change until proven otherwise.

With early diagnosis and treatment the prognosis for a patient with squamous cell carcinoma is good. Key words: Osteoclastoma, Osteomyelitis, Sinus tract, Squamous cell carcinoma.