Carl T. Hasselman

Inhibition of Wear Debris Mediated Osteolysis in a Canine Total Hip Arthroplasty Model

In this study the efficacy of an oral bisphosphonate therapy to inhibit wear debris mediated bone resorption was evaluated in a canine total hip replacement model. Adult canines were randomized to three groups (n = 8 each) with a right uncemented total hip replacement performed on each animal. Group I (control) received no particulate debris. In Groups II and III, a mixture of 1 x 10(9) particles were introduced into the proximal femoral gap intraoperatively. The particle mixture consisted of fabricated ultra high molecular weight polyethylene (mean 2.3 microns, 90% by number), titanium alloy (mean 3.1 microns, 5%), and cobalt chrome alloy (mean 0.8 micron, 5%). Group III canines additionally received oral drug therapy (5 mg once a day, alendronate sodium) which was begun on postoperative Day 7 and continued until the time of sacrifice. Postoperatively, all animals were allowed 24 weeks of full ambulation before euthanasia. Radiographs obtained preoperatively, postoperatively, and at time of sacrifice were evaluated for periprosthetic osteolysis. Interfacial tissues were examined histologically and placed in organ culture and the supernatants were assayed for prostaglandin E2 and interleukin-1. One animal receiving debris (Group II) suffered a periprosthetic fracture and was sacrificed from the study. Radiographically, one of eight Group I (control) and six of seven canines from Group II (debris) had periprosthetic radiolucencies with endosteal scalloping develop. In contrast, only one of eight animals from Group III (debris + alendronate) had periprosthetic radiolucencies develop. Whereas tissues from control animals were mostly fibrous and acellular, tissues from both experimental groups had significant macrophage infiltration. Levels of prostaglandin E2 and interleukin-1 were elevated significantly in periprosthetic tissues from both experimental groups compared with controls. Continuous administration of alendronate effectively inhibited bone lysis for the 24-week duration of the study. This is consistent with the literature indicating that alendronate is incorporated in the mineralizing matrix making it refractory to osteoclastic resorption. This report has significant clinical implications for controlling the most common cause of implant failure.

Foot and ankle fractures in elderly white women. Incidence and risk factors.

Background: Although foot and ankle fractures are among the most common nonspinal fractures occurring in older women, little is known about their epidemiology. This study was designed to determine the incidence of and risk factors for foot and ankle fractures in a cohort of 9704 elderly, nonblack women enrolled in the multicenter Study of Osteoporotic Fractures. Methods: At their first clinic visit, between 1986 and 1988, the women provided information regarding lifestyle, subjective health, and function. Bone mineral density was measured in the proximal and distal parts of the radius and in the calcaneus. The women were followed for a mean of 10.2 years, during which time 301 of them had a foot fracture and 291 had an ankle fracture. The fractures were classified with use of a modification of the Orthopaedic Trauma Associations guidelines. Results: The incidence of foot fractures was 3.1 per 1000 woman-years, and the incidence of ankle fractures was 3.0 per 1000 woman-years. The most common ankle fracture was an isolated fibular fracture (prevalence, 57.6%), and the most common foot fracture was a fracture of the fifth metatarsal (56.9%). Women who sustained an ankle fracture had been slightly younger at the time of study enrollment than the women who did not sustain such a fracture (71.0 compared with 71.7 years), they had a higher body mass index (27.6 compared with 26.5), and they were more likely to have fallen within the twelve months prior to filling out the original questionnaire (38.1% compared with 29.7%). The appendicular bone mineral density was not significantly different between these two groups of subjects. Women who sustained a foot fracture had a lower bone mineral density in the distal part of the radius (0.345 g/cm 2 compared with 0.363 g/cm 2 ) and a lower calcaneal bone mineral density (0.394 g/cm 2 compared with 0.404 g/cm 2 ) than the women without a foot fracture, they were less likely to be physically active (62.3% compared with 67.8%), and they were more likely to have had a previous fracture after the age of fifty (45.5% compared with 36.8%) and to be using either long or short-acting benzodiazepines. Conclusions: Overall, foot fractures appeared to be typical osteoporotic fractures, whereas ankle fractures occurred in younger women with a relatively high body mass index. Level of Evidence: Prognostic study, Level I-1 (prospective study). See Instructions to Authors for a complete description of levels of evidence.

An Explanation for Various Rectus Femoris Strain Injuries Using Previously Undescribed Muscle Architecture

We performed cadaveric dissection of the rectus femo ris muscle to correlate the various lesions of strain injury seen with imaging studies to the muscular anatomy. The proximal tendon is composed of a superficial, an terior portion from the direct head, and a deep intra muscular portion from the indirect head. The muscle fibers arising from the anterior superficial tendon of the direct head travel in a posterior and distal direction to insert on the posterior tendon of insertion, giving the proximal muscle a unipennate architecture. Muscle fi bers from the intramuscular tendon of the indirect head originate on both the medial and lateral sides of the tendon and insert on the distal posterior tendon to cre ate its bipennate structure. Three chronic strain injuries involving the midmuscle belly substance were explored grossly and microscopically. It appears that one type of acute strain injury occurs in the midmuscle belly with disruption of the muscle-tendon junction of the intra muscular tendon resulting in local hemorrhage and edema. More chronically, this hematoma organizes into a fatty, loose connective tissue encasement of the deep intramuscular proximal tendon. Serous fluid from the hematoma may remain within the connective tissue sheath, creating a pseudocyst with the deep intra muscular tendon of the indirect head at its center. The muscles anatomy helps to explain a different rectus femoris strain injury.

Metatarsal Head Resurfacing for Advanced Hallux Rigidus

Background: Advanced stages of first metatarsophalangeal (MTP) arthritis have traditionally been treated with various arthroplasties or arthrodesis. Studies suggest the outcomes of arthrodesis are superior to those of metallic joint replacement; however, complications and suboptimal outcomes in active patients still remain with arthrodesis of the first MTP joint. This study reports results of patients with advanced MTP arthritis who underwent metallic resurfacing of the metatarsal side of the MTP joint. Methods: From 2005 to 2006, 26 patients (30 implants) with stage II or III hallux rigidus underwent resurfacing with the HemiCAP® implant and consented to participate in a study comparing pre- and postoperative radiographs, range of motion (ROM), American Orthopedic Foot and Ankle Society, and Short Form 36 Health Survey (SF-36) scores. Average age of these patients was 51 years. Patients were assessed at a mean of 27 months with outcome measures and contacted at 60 months to assess current symptoms and satisfaction. Results: Assessment at 27 months demonstrated statistically significant improvements in ROM, AOFAS, and SF-36 scores (P < .05) when compared to baseline. Mean preoperative AOFAS scores improved from 51.5 to 94.1. Mean active ROM improved from 19.7 to 47.9 degrees. Mean passive ROM improved from 28.0 to 66.3 degrees. Mean RAND SF-36 physical component score improved significantly from 66.7 to 90.6. Average time for return to work was 7 days. At 60 months, all patients reported excellent satisfaction with their current state and would repeat the procedure. Implant survivorship was 87% at 5 years. Of the 30 implants, 4 were revised at 3 years. Conclusion: The results at 5 years were very promising. Preservation of joint motion, alleviation of pain, and functional improvement data were very encouraging. Because minimal joint resection was performed, conversion to arthrodesis or other salvage procedures would be relatively simple if further intervention became necessary. Level of Evidence: Level IV, prospective case series.

Resurfacing of the Metatarsal Head to Treat Advanced Hallux Rigidus.

Advanced stages of hallux rigidus are usually treated with various arthroplasties or arthrodesis. Recent results with resurfacing of the metatarsal head have shown promising results and outcomes similar or superior to those of arthrodesis. In this article, the authors show their preoperative decision making, surgical techniques, postoperative management, results, and a comparative literature review to identify metatarsal head resurfacing as an acceptable technique for the treatment of advanced hallux rigidus in active patients. Key points in this article are adequate soft tissue release, immediate rigid fixation of the components, and appropriate alignment of the components.

When groin pain signals an adductor strain

In brief Adductor strains typically occur brief with forceful abduction of the thigh during adduction or with hyperabduction. The history and physical exam are usually diagnostic; however, other causes of acute groin pain must always be ruled out. Using CT, MRI, or ultrasound can facilitate diagnosis of difficult or unusual cases. Management of acute partial strains usually requires nonsteroidal anti-inflammatory drugs, ice, compression, physical therapy, and rest. The mainstay of treatment is early active rehabilitation and returq to competition. Surgery is often required for complete ruptures, but the treatment for such injuries remains under discussion.

Subtalar Coalitions in the Adult

Tarsal coalitions, while relatively uncommon, are typically identified in adult patients during an evaluation for ankle instability, sinus tarsus pain, and/or pes planovalgus. The true incidence of tarsal coalition is unknown with estimates ranging from 1% to 12% of the overall population. The most common area of involvement of the subtalar joint is the middle facet, and heightened awareness should be present in adult patients with limited motion of the subtalar joint. Standard radiographic imaging, to include a Harris heel view, is recommended initially, although computerized tomography scan and MRI are often necessary to confirm the diagnosis.