No abstract

Although trabecular bone structure has been evaluated, variation with knee compartment and depth from joint surface is not completely understood. Cadaver knees were evaluated with microcomputed tomography analysis for these variations. Objective differences were compared between: medial vs. lateral compartments; femoral vs. tibial bone; and normal vs. arthritic knees. Depth dependent changes in the parameters were observed for the first 6 mm of the cores in normal knees: BV/TV, Tb.N and Conn.D gradually decrease, while Tb.Sp and SMI increase. In the first 6 mm of the normal tibia BV/TV, Tb.N, and Tb.Th are greater than in the femur on both the medial and lateral compartments while Tb.Sp, SMI, and C0nn.D are lower. The medial compartment values for BV/TV, Tb.N, Tb.Th and C0nn.D are generally greater than for the lateral in both the femur and tibia while Tb.Sp and SMI are lower. In comparison of normal vs. arthritic knees significant differences are observed in the first 6 mm of the medial tibia. With arthritis BV/TV and Tb.Th are lower, while SMI and Tb.Sp are higher. Tb.N and C0nn.D show no statistically significant difference. The bone structure variations are, thus, most prominent in the first 6 mm of depth and medial compartment bone is generally more structurally sound than lateral. Severely arthritic bone changes are most prominent in the medial compartment of the tibia and bone structure is less sound in severe arthritis.

The sacroiliac joint (SIJ) as a source of symptoms has been controversial; however, as knowledge about the joint increased, its role as a pain generator in patients complaining of symptoms that are often attributed to spinal pathology has become better appreciated. The literature reports that the SIJ is the pain origin in as many as 30% of patients presenting with low back pain. Clinically, the SIJ can be challenging to evaluate; however, assessing pain location, patient posture/movement, and provocative manual testing are useful in making the presumptive diagnosis of SIJ disruption. The most definitive evaluation is image-guided injection of anesthetic solutions into the joint which is diagnostic if there is at least 75% symptom relief acutely. Treatment begins with nonoperative intervention including physical therapy and/or chiropractic care. If these fail, the next option is generally radiofrequency denervation (rhizotomy) of the joint. If this does not provide adequate relief, surgical intervention, in the form of minimally invasive SIJ fusion may be considered. The literature increasingly supports favorable results of SIJ fusion in appropriately selected patients. The purpose of this review is to provide an overview of the current literature on the SIJ, with focus on its surgical treatment.

The use of rhBMP-2 did not enhance the fusion rate in stand-alone ALIF with FRAs. In fact, the trend was toward a higher nonunion rate with rhBMP-2, although this was not significant with the numbers available. This result appears to be caused by the aggressive resorptive phase of allograft incorporation, which occurs before the osteoinduction phase.