Volume 13-4, Winter 2004

Few articles have addressed the bone strength of the proximal tibia. This study attempts to quantify the compressive strength of bone in the proximal tibia of human cadaveric knees at increasing distance from the joint surface. Sixteen fresh-frozen human cadaveric knees were tested. The proximal tibia was sequentially sectioned into 1-cm slices, starting 2 mm below the chondral surface of the medial tibial plateau. Four slices were obtained from each knee. Each slice was then loaded to failure under an axial load. The proximal slice of bone had a significantly higher average maximum load to failure than the more distal slices. The second, third, and fourth slices of bone withstood 77%, 61%, and 73% of the average load of the proximal slice, respectively. This study was designed to simulate how the proximal tibia is loaded under an uncemented tibial base plate after total knee arthroplasty. The results are in agreement with previous studies that have shown the proximal 1 cm of tibial bone to have the highest resistance to compressive loads. Previous studies on the bone strength of the proximal tibia have focused on more proximal portions of bone than the current study. This study demonstrates that the load to failure of tibial resection surface decreases significantly with increasing distance from the joint line until the 4th cm of bone beneath the joint line is encountered. This information may play a role in surgical decision making and implant design. (Journal of Surgical Orthopaedic Advances 13(4):195–198, 2004) Key words: arthroplasty, bone strength, knee replacement, proximal tibia

Surveys for assessing outcomes of spine surgery are typically cumbersome and require statistical analyses, which make their use impractical in nonacademic settings. The objective of this study was to develop a short pain survey (SPS) to assess patient satisfaction following spinal surgery and to compare the results with those of the Brief Pain Inventory–Short Form (BPI-SF), which is widely used in academic settings. Patients (n D 101) completed the BPI-SF prior to spinal fusion. Six months after surgery, patients completed the BPI-SF and SPS. Marginal homogeneity tests and paired t tests of the BPI-SF indicated highly significant (p < .001) postoperative improvements. One-sample binomial tests and Blyth–Still–Casella 95% confidence intervals also indicated highly significant (p < .001) postoperative improvements with SPS. There was a highly significant congruence (p < .002) between the responses for the two surveys. It was concluded that the SPS can be easily used in nonacademic settings to assess patient satisfaction and clinical success following spine surgery. (Journal of Surgical Orthopaedic Advances 13(4):199–205, 2004) Key words: short pain survey, spinal fusion

This prospective study of 52 patients from the authors’ institutional carpal tunnel database investigated which patient subpopulations were most likely to benefit from carpal tunnel release and documented the time course of recovery. Preoperatively and postoperatively at 6 and 12 months, patients completed a Levine–Katz questionnaire, and NC-Stat studies and clinical parameters were recorded by a certified occupational therapist. For individual parameters from preoperative to 6 months postoperative, statistical improvements were found in Tinel’s and Phalen’s signs, pinch strength, delayed motor latency, and symptom severity and functional scores. None of these parameters changed significantly from 6 to 12 months. Grip strength did not change significantly postoperatively. Analysis based on age or carpal tunnel release technique showed no differences postoperatively. Preoperative symptom and functional scores correlated statistically with postoperative scores, peaking at 6 months postoperatively. The study concluded that most clinical signs and symptoms of carpal tunnel release fail to improve after 6 months postoperatively. (Journal of Surgical Orthopaedic Advances 13(4):206–209, 2004) Key words: carpal tunnel, Levine–Katz, outcome, surgery

Although many different pathogeneticmechanisms have been proposed for osteonecrosis of the femoral head, the repair process leads to structural collapse when bone resorption exceeds production. The purpose of the current study was to determine the effects of two agents with known bone-altering qualities, alendronate and simvastatin, on the healing response of a cryosurgically induced necrotic lesion of the femoral head in canines. Eighteen beagles had cryosurgical necrosis of the right femoral head. After 2 weeks, in a blinded, placebo-controlled, randomized fashion, a 10-mg dose of oral alendronate (n = 6), a 40 mg dose of simvastatin (n = 6), or a placebo (n = 6) was administered daily for 12 weeks. At sacrifice, bone densitometry and histomorphometry quantified bone in the femoral head. In the alendronate-treated animals, a 16% increase in bone mineral density of the femoral head with induced osteonecrosis was found compared with the placebo group. Increases in bone volume and trabecular thickness also were detected in the alendronate and simvastatin groups, with alendronate having the greatest effect. Clinically, increasing the amount of bone in the femoral head may forestall mechanisms leading to joint collapse characteristic of advanced osteonecrosis of the femoral head. (Journal of Surgical Orthopaedic Advances 13(4):210–216, 2004) Key words: bisphosphonates, bone desitometry, bone histomorphometry, dogs, osteonecrosis, statins

A case report is presented of a 45-year-old woman with an 18-month history of pain and swelling in her right ankle. There was no history of trauma. Routine investigations failed to elicit a diagnosis. The patient had been on warfarin anticoagulation therapy for 12 years. The onset of symptoms coincided with a period of poor control of her anticoagulation therapy and her international normalized ratio was recorded at 5 or above on three occasions. A diagnosis of pigmented villonodular synovitis (PVNS) was made on arthroscopic examination of her ankle; this was confirmed histologically. The etiology of PVNS remains controversial. Hemarthrosis has been suggested as an etiological factor. Although there are reports of PVNS in patients with hemophilia, there are no reports of PVNS occurring in patients on anticoagulation therapy. This case report supports a possible role for hemarthrosis in the etiology of PVNS. (Journal of Surgical Orthopaedic Advances 13(4):217–219, 2004) Key words: ankle, anticoagulation therapy, pigmented villonodular synovitis

Bone islands are hamartomatous malformations in the bone that are known to be asymptomatic in nature. Two cases are presented in which the presence of bone islands in the femur led to difficulty with the introduction of a femoral prosthesis. In one case, this led to fracture of the medial part of the cortex, which was fixed with a screw prior to insertion of the prosthesis. In the second case, a window was made in the femur to remove hard bone sufficient for insertion of the prosthesis. This was closed with steel wires prior to insertion of the cemented femoral stem. These cases illustrate the problems that can be encountered during surgery in the presence of bone islands. The surgeon should evaluate the site, size, and location of bone islands during preoperative planning before performing surgery. (Journal of Surgical Orthopaedic Advances 13(4):220–223, 2004) Key words: arthroplasty, giant bone island

Recent studies have shown that not all lumbar disc herniations are symptomatic and that when followed longitudinally, these patients develop back pain independent of the previous imaging study. This is a case report of two patients with radicular symptoms and lumbar disc herniations that underwent diagnostic injections to locate their pain generator. Both patients failed to respond to transforaminal epidural steroid injections. Transforaminal injections can be diagnostically sensitive for radicular pain but not specific. This is a direct result of the spread of medication to other levels in the epidural space, thus affecting multiple levels of innervation. Follow-up with two sacroiliac injections gave significant relief of their pain. They were both treated conservatively for sacroiliac joint pain and did well. One remained pain free after several months and the second remained with minimal pain until she presented again in her 3rd month of pregnancy with return of her pain. The differential diagnosis of lumbar radicular pain is discussed as well as the authors’ experience in using diagnostic injections. (Journal of Surgical Orthopaedic Advances 13(4):224–227, 2004) Key words: disc, herniation, radicular, sacroiliac