The purpose of this paper is to provide a brief background on the concept of primary care physical therapy, describe 3 existing models of primary care physical therapy, explore their similarities and differences, and discuss the potential implications and opportunities for the profession. The programs at US Army medical facilities, Kaiser Permanente Northern California and the Department of Veterans Affairs Salt Lake City Health Care System, are presented by the author affiliated with each respective program. J Orthop Sports Phys Ther. 2005;35(11):699-707. Key Words: differential diagnosis, direct access, health policy

Study Design: Resident's case problem. Background: A 52-year-old Chinese male with a 10-year history of gradually worsening right hip stiffness, weakness, and pain was referred to physical therapy by his orthopedist, who made a diagnosis of developmental dysplasia of the right hip, with possible Legg-Calve-Perthes disease. The patient reported multiple falls over the last several years and a gradual onset of low back pain with an onset of ‘"electricity’" down both legs. The patient also reported mild numbness in both forearms and the right hand over the previous several months. This resident's case problem illustrates how a physical therapist recognized the presence of an atypical musculoskeletal pathology through the use of hypothesis-driven clinical reasoning and detailed physical examination. Diagnosis: Examination of the patient's lumbar and cervical spine and hips revealed joint dysfunctions. Neurological testing revealed hyperreflexia. Special testing revealed lower extremity clonus with a positive Babinski sign with gait disturbances. The patient was referred back to his primary physician and then to a neurologist and neurosurgeon. An MRI revealed cervical myelopathy due to ossification of the posterior longitudinal ligament from C3/C4 to C5/C6. The patient then underwent a C3 through C7 laminectomy. Discussion: It is always imperative that sound clinical reasoning be used when performing physical therapy evaluations, regardless of the referral status of the patient. Patients with nonmusculoskeletal pathology may seek physical therapy services and it is the physical therapist's responsibility to complete a thorough examination and refer to specialists when appropriate. J Orthop Sports Phys Ther. 2005;35(11):722-729. Key Words: cervical spine, myelopathy, neck, spine, spinal cord

Study Design: Resident's case problem. Background: The purpose of this resident's case problem is to describe a 39-year-old female patient with insidious onset of hip pain. This patient had discrete findings on subjective and physical examination that prompted referral for further imaging studies of the left hip and pelvis. Despite having seen multiple providers, no imaging of the involved hip or pelvis had been performed. A prolonged duration of symptoms, severe gait disturbance with an associated Trendelenburg sign, difficulty sleeping, and an empty end feel with passive range of motion increased concern that a pathological process might be present. Diagnosis: Imaging studies revealed a large destructive soft-tissue tumor later found to be non-Hodgkin's lymphoma. Discussion: It is incumbent upon physical therapists to be aware of the potential for severe pathological conditions that mimic musculoskeletal complaints to exist and understand how to identify patients for whom further testing and/or referral may be appropriate. Existing guidelines for low back pain may assist with decision making in the absence of specific guidelines for when to request imaging in patients with nontraumatic hip and pelvis pain. Proficiency in screening for conditions not amenable to physical therapy treatment or that require consultation to other health care professionals is essential to physical therapy practice. J Orthop Sports Phys Ther. 2005;35(11):738-744. Key Words: cancer, pelvis, physical therapy, radiology, screening

Study Design: Resident's case problem. Background: Acute back pain most often presents as musculoskeletal in nature; however, less frequently it may be the result of an underlying, or coexisting, systemic pathology. When present, the signs and symptoms of systemic pathology can mimic, or be masked by, musculoskeletal back pain, which may pose a diagnostic challenge during the clinical evaluation. The purpose of this resident's case problem is to describe the clinical reasoning process leading to a medical referral for a patient who presented to physical therapy with debilitating low back pain. Diagnosis: The patient in this resident's case problem was a 67-year-old male referred to physical therapy with a 2-week history of severe low back pain and muscle spasms. The patient history and physical examination were suggestive of musculoskeletal back pain and physical therapy treatment was initiated. Abdominal pain was elicited during an introductory therapeutic exercise, which was recognized by the therapist as a potential sign of abdominal pathology. The therapist performed an additional review of systems and an abdominal screening examination, which established the necessity of an immediate medical referral. At the emergency department, ominous abdominal pathology was safely ruled out through diagnostic imaging and the patient was treated for secondary gastrointestinal effects of opioid analgesic medications. Discussion: This resident's case problem provides an opportunity to discuss the clinical reasoning process leading to the suspicion of abdominal pathology. Specifically, this case reinforces the importance of recognizing potential signs of systemic pathology, executing an appropriate physical examination, including screening of the involved anatomical region, and providing an appropriate medical referral when indicated. J Orthop Sports Phys Ther. 2005;35(11):755-764. Key Words: differential diagnosis, low back, lumbar spine evaluation, pharmacology, primary care