Faculty Bibliography

Foot drop has many etiologies. One rarely mentioned and often neglected reason for foot drop is an acute inversion sprain of the ankle. Over the past 14 years, a collection of 32 cases of foot drop have been compiled in our orthopaedic and physiatric practices. All cases had appropriate evaluations, including electrodiagnostic studies (electromyography and nerve conduction studies) to determine the location and type of injury. Treatment and follow-up are also discussed. Of the 32 case studies, four were caused by a straightforward acute inversion sprain of the ankle. These cases are described with the electrodiagnostic evaluations, treatments, and outcomes. Proposed mechanisms for this type of foot drop are discussed, including traction and compression of the common peroneal nerve as it winds around the neck of the fibula, and possible compression by hematoma. Surgical versus conservative treatment is described. The functional impairment associated with foot drop is detailed

Pigmented villonodular synovitis (PVNS) is a rare disorder that may involve the synovium of joints, bursa, or tendon sheaths. Monoarticular involvement is typical, with the knee most commonly affected. Localized pigmented villonodular synovitis (LPVNS) involves a discrete region of the synovium. Detection and diagnosis of this entity is clinically challenging, and plain radiographs are usually unremarkable. Magnetic resonance imaging (MRI) has been reported to be sensitive for the detection of synovial abnormalities and is the imaging modality of choice in suspected cases of LPVNS. When the diagnosis remains in doubt, arthroscopy may be used for direct visualization of synovial pathology, as well as to obtain tissue for histologic analysis. Definitive treatment may also be performed at the time of arthroscopy. We present a case of LPVNS in which a large (4 cm) lesion was not apparent on preoperative radiographs or MRI and was also missed on initial diagnostic arthroscopy

Recent research in total hip arthroplasty has focused on attempts to decrease wear at the femoral head-acetabulum articulation, to limit the production of debris that is believed to lead to osteolysis and prosthetic loosening. The use of ceramic-on-polyethylene bearing surfaces has been reported to produce lower wear rates and therefore may increase the life expectancy of the joint arthroplasty. Problems with this bearing have been reported to be due to ceramic femoral head fracture. Reported here are 2 cases of catastrophic failure of total hip arthroplasties, involving a ceramic femoral head, caused by failure of the polyethylene acetabular liner, with subsequent penetration of the femoral head through the acetabular shell

Varus, valgus, and retroversion-anteversion displacements of femoral neck fractures are easily identified on standard AP and lateral radiographs, but rotational malalignments are frequently overlooked. Alterations of the normal appearance of the trabecular systems will indicate rotatory malalignments. A misleading picture of what seems to be severe osteoporosis may actually be due to malrotation and disappearance of the normal trabecular pattern on radiograph.

With the increase in the use of shoulder arthroscopy in the past decade, there has been an increased awareness of complications. Reports of the occurrence of transient neuropraxia indicate an incidence of 10%-30%. The recording of somatosensory evoked potentials (SEP) for the study and functional monitoring of the sensory pathway is well accepted as a reproducible method of monitoring peripheral nerve and spinal cord function during surgery. SEPs were recorded during shoulder arthroscopy in 20 patients to monitor the musculocutaneous nerve, ulnar nerve, and either the median or radial nerve. In all 20 cases, abnormal SEPs of the musculocutaneous nerve were demonstrated. In 16 cases, this was produced upon initial joint distention, and in 15 cases, by traction; in 11, by longitudinal traction of greater than or equal to 12 lb, and in six by perpendicular traction of greater than or equal to 7 lb. In 10 patients, there were varying combinations of median, ulnar, and radial nerve involvement. There were two cases of clinical neuropraxia in this series. One resolved in 24 h and one in 48 h. The conclusion is that there is a real potential for neurologic damage during shoulder arthroscopy and that the musculocutaneous nerve is the most vulnerable. Factors responsible include joint distention, excessive traction, and extravasation of fluid. The use of SEPs provides a reliable means for monitoring the neurologic status of the extremity during shoulder arthroscopy.

Fourteen patients (16 knees) underwent total knee arthroplasty with a noncemented tibial component. Clinical evaluation at one year and two years showed a level of function and pain relief comparable to that reported in studies of cemented prostheses. Radiographic studies demonstrated evidence of active bone implant consolidation.