Volume 16-4, Winter 2007

Recent studies have shown that an increase in bone ingrowth by addition of osteogenic growth factors can reduce micro motion and gross implant motion and contribute to joint implant stability through osseointegration. Platelet-rich plasma (PRP) has the potential to provide growth factors that may be conducive to osteointegration at the bone–implant interface. This study analyzed the influence of PRP on bone ingrowth upon a beaded metal implant in distal femurs of 22 rabbits. Rabbit limbs were randomly assigned to receive an implant plus PRP or plain implant. Half of the specimens were randomly assigned to a 2-week group (n D 20) or a 5-week group (n D 20). Histologic and histomorphometric comparison between implant alone and implant plus PRP, at 2 and 5 weeks, was performed. In both the 2- and 5-week comparisons, there was no statistical difference (p > .05) in bone ingrowth between the control and PRP group, despite a slight increase in trabecular bone growth in PRP groups. This study suggests that PRP is not a major contributing factor to bone ingrowth at the bone–implant interface. This supports growing evidence in the literature that PRP can lead to variable bone growth stimulation in vivo. (Journal of Surgical Orthopaedic Advances 16(4):159–163, 2007) Key words: osteointegration, platelet-rich plasma, total joint arthroplasty

Excessive polyethylene wear is recognized as one of the most important factors affecting the durability of total knee arthroplasty; however, bearing surface wear is a multifactorial problem. The purpose of this study was to identify factors for polyethylene wear and failure in primary posterior cruciate-retaining (PCR) total knee arthroplasty (TKA) in two disparate cohorts (American and Japanese). Seventy-three total knee arthroplasty operations were performed on 48 Japanese patients, and 76 on 63 American patients with noninflammatory arthritides. All patients were evaluated clinically and radiographically using a total joint arthroplasty database. Age, weight, diagnosis, Knee Society patient category, prosthesis size, insert thickness, alignment, polyethylene wear, osteolysis, Knee Society knee score, Knee Society pain score, and radiographic and clinical survivorship were evaluated. Seventy-three Japanese TKAs were followed for a mean of 6.6 years (range, 2.0–10.6). Three (4.1%) Japanese patients required revision. Seventy-six American TKAs were followed for a mean of 9 years (range, 2–10.2). Two (2.6%) American patients required revision. The American patients were significantly older, heavier, male predominant, and required larger size implants. The Japanese patients were significantly more female predominant and had a significantly less postoperative arc of motion. Knee Society knee and pain scores, survivorship, average total polyethylene wear, and annual wear rates were not different among the two cohorts. PCR TKA had similar survivorship in disparate cohorts of Japanese and American total knee arthroplasty patients despite smaller stature patients in the Japanese cohort. Cultural, gender-specific, and morphologic differences need to be considered for knee implant design. However, survivorship and polyethylene wear rates appear to be independent of these factors in disparate populations. (Journal of Surgical Orthopaedic Advances 16(4):164–170, 2007) Key words: activity level, arthritis etiology, polyethylene wear, posterior cruciate retaining total knee arthroplasty

Pneumatic tourniquets about the thigh are commonly employed in lower extremity orthopaedic surgery to maintain a bloodless operative field. The purpose of this study was to determine whether the position of the knee at the time of tourniquet inflation has an impact on knee range of motion (ROM). Passive ROM of the knees of 30 patients was measured with the tourniquet deflated, with the tourniquet inflated while the knees were in extension, and with the tourniquet inflated while the knees were in flexion. The average knee ROM with a deflated tourniquet was 143.0° with a standard deviation of 8.1° (range, 125° –160°). When the tourniquet was inflated with the knees in extension, the average knee ROM was 143.0° with a standard deviation of 7.8° (range, 125° –159°). When the tourniquet was inflated with the knees in flexion, the average knee ROM was 143.7° with a standard deviation of 7.8° (range, 124° –160°). There was a statistically significant difference between the ROM of knees with tourniquet inflation in flexion versus extension (p D .0011.) Although there was a statistical difference, it was concluded that a difference of approximately 1° in knee ROM is not clinically relevant. (Journal of Surgical Orthopaedic Advances 16(4):171–173, 2007) Key words: knee, range of motion, tourniquet

This article reports on the surgical treatment of 14 consecutive patients with paralytic spinal deformities secondary to spinal cord injury occurring in childhood. Eleven patients underwent a posterior spinal fusion and three patients underwent a combined anterior and posterior spinal arthrodesis. Luque rods were used in all but one patient. The spinal fusion extended to the sacrum in 10 patients. No patient developed postoperative wound infections or medical complications. Four patients (28.6%) who underwent initially a posterior spinal arthrodesis developed pseudarthrosis. This was treated successfully by a combined anterior and posterior spinal fusion in two patients. The remaining patients underwent a revision posterior spinal fusion with recurrence of the nonunion in one patient. A combined anterior and posterior spinal arthrodesis could be considered the treatment of choice for patients with severe deformities who can tolerate anterior surgery. If pseudarthrosis develops following posterior spinal fusion, this can be best treated by a combined anterior and posterior revision procedure with instrumentation. (Journal of Surgical Orthopaedic Advances 16(4):174–186, 2007) Key words: paralytic, scoliosis, spinal cord injury, spinal deformity, surgical treatment

The role of the peroneal tendons as static stabilizers of the ankle is poorly understood. Anterior-posterior displacement of the talus was evaluated in eight fresh-frozen cadaveric ankle joints. With the distal tibia stabilized, loads of 150 N were applied to the talus in the anterior direction while the ankle was held in neutral. All tests were initially performed on intact specimens. Loads were reapplied after sequential sectioning of the peroneal tendons and superior peroneal retinaculum and then the anterior talofibular ligament. When compared with intact ankles, releasing the peroneal tendons caused an average increase of 15% displacement (0.90 mm, p < .05). Adding the release of the anterior talofibular ligament increased the anterior displacement an additional 16% (1.35 mm, p < .05) for a combined anterior laxity of 34% (2.25 mm, p < .05). The data suggest that the peroneal tendons along with the superior peroneal retinaculum provide static resistance to anterior talar displacement with the ankle in neutral. This may contribute to the overall stability of the lateral ankle not previously recognized. (Journal of Surgical Orthopaedic Advances 16(4):187–191, 2007) Key words: ankle, anterior talofibular ligament peroneal tendons, superior peroneal retinaculum

A communicating branch between the median and superficial ulnar nerve in the palm of the hand has been described, but its relationship to the cutaneous anatomy of the hand has had little emphasis. Fifty preserved cadaveric hands were dissected. A communicating branch was found in 37 of 50 specimens. In 34 specimens, the connecting branch proceeded from the ulnar nerve to enter the median nerve distally; in three specimens it proceeded from the median nerve to reach the ulnar nerve distally. This study describes the communicating branch in relation to the distal crease of the wrist with the axis of the third webspace and fifth ray as the radial and ulnar borders, respectively. This study may aid surgeons in determining the likelihood of injury in trauma or during various surgical procedures. (Journal of Surgical Orthopaedic Advances 16(4):192–195, 2007) Key words: communicating branch in the hand, median nerve, sensory communication, ulnar nerve

Mycobacterium fortuitum is a member of the rapidly growing nontuberculous mycobacteria. Although mortality is rare from M. fortuitum, morbidity depends on the localized site of infection. M. fortuitum is ubiquitous in the environment and has been reported to cause infections of prosthetic devices. There have been seven previously reported cases of prosthetic joint infections due to M. fortuitum. This article presents three additional cases of postoperative joint infections due to M. fortuitum. All three cases were confirmed to be genetically indistinguishable by pulse-field gel electrophoresis. Awareness of its importance is especially noteworthy in the realm of ongoing antibiotic resistance. (Journal of Surgical Orthopaedic Advances 16(4):196–198, 2007)

Coracoid osteoid osteomas are rare. This case report presents two patients with coracoid osteoid osteomas who developed neurologic sequelae of the infraclavicular brachial plexus (namely, musculocutaneous neuropathy in one patient with an anterior lesion, and suprascapular neuropathy in the other patient with a more posterior lesion). The neuropathy was due to soft tissue edema, which surrounded the bony lesion and was apparent on MRI. Surgical resection of the bony lesion in both cases produced excellent outcomes at long-term follow-up. (Journal of Surgical Orthopaedic Advances 16(4):199–203, 2007) Key words: brachial plexopathy, coracoid process, osteoid osteoma

Free vascularized fibula graft surgery has been shown to be successful in the treatment of osteonecrosis of the femoral head. Refinements in the surgical technique have greatly decreased patient morbidity and overall surgical time. Careful placement of the hip incision is one such refinement. Specific bony landmarks to map out the location of the incision and a simple technique for incision placement are described. An accurately placed 10- to 15-cm incision will allow access to both the proximal femur and the ascending branch of the lateral femoral circumflex artery and veins. (Journal of Surgical Orthopaedic Advances 16(4):204–206, 2007) Key words: avascular necrosis, free vascularized fibula graft, osteonecrosis, surgical technique