Maya E. Pring

Chondrosarcoma of the Pelvis: A Review of Sixty-four Cases

Background: Treatment of pelvic chondrosarcoma is a difficult problem for the musculoskeletal oncologist. Poor rates of survival and high rates of local recurrence after surgical treatment have been reported in previous studies. The present study was designed to review the long-term oncologic and functional outcomes of surgical management in a large series of patients with pelvic chondrosarcoma who were treated at a single institution. Methods: The cases of sixty-four patients with localized pelvic chondrosarcoma that had been surgically treated between 1975 and 1996 were reviewed retrospectively. The study was limited to patients who had received no previous treatment for chondrosarcoma. There were forty-one male and twenty-three female patients who had a mean age of forty-seven years (range, fifteen to eighty-eight years). The patients were followed for a minimum of three years or until death. The median duration of follow-up of the living patients was 140 months (range, thirty-nine to 295 months). Results: Thirty-three of the sixty-four patients were first seen with grade-1 chondrosarcoma; twenty-three, with grade-2; one, with grade-3; and seven, with grade-4 (dedifferentiated chondrosarcoma). Thirteen patients had a hemipelvectomy to achieve local tumor control, whereas fifty-one patients underwent a limb-salvage procedure. Twelve patients (19%) had local recurrence, and eleven (17%) had distant metastases. At the time of the final follow-up, forty-four patients (69%) were alive without evidence of disease, thirteen (20%) had died of the disease, six (9%) had died of unrelated causes, and one (2%) was alive with disease. Less than a wide surgical margin correlated with local recurrence (p = 0.014). High-grade tumors correlated with poor overall survival (p < 0.001). All patients who had a limb-salvage procedure were able to walk at the time of the final follow-up, and they had a mean functional score of 77%, according to the system of the Musculoskeletal Tumor Society. Conclusions: Aggressive surgical resection of pelvic chondrosarcoma results in long-term survival of the majority of patients. There is a high correlation between tumor grade and overall or disease-free survival.

Sulcus Morphology of the Distal Femur

Traditional images of the distal femur place the intercondylar groove midway between the condyles. The location of the sulcus of the intercondylar groove in a large Sudanese skeletal population was verified using a custom stereotactic device. The results of this study show that the femoral sulcus is lateral to the midplane between the 2 femoral condyles. This study also shows that the configuration of the sulcus is linear and is oriented between the traditional anatomic and mechanical axes of the femur.

Compartment syndrome following intramedullary fixation of pediatric forearm fractures.

This study was designed to evaluate the incidence of compartment syndrome (CS) resulting from the treatment of both-bone forearm fractures in children. A retrospective analysis of 285 consecutive children who presented with both-bone forearm fractures was performed. Of 235 closed injuries, 205 were treated with closed reduction and casting; none of these patients developed CS. Thirty of the closed injuries were treated with closed reduction and intramedullary fixation; three of these patients (10%) developed CS. Fifty patients sustained open fractures and were treated with debridement and open reduction with intramedullary pinning; CS developed in three of these patients (6%). The eighty patients treated with intramedullary fixation had an increased incidence of CS compared with the 205 patients treated with closed reduction and casting (P < 0.001). Within the group of patients who had surgery, patients with longer operative times and more use of intraoperative fluoroscopy were at higher risk of developing CS.

Impingement and childhood hip disease.

Hip impingement is now recognized as a relatively common cause for hip pain in young adults. The early evolution of impingement begins in childhood in several common hip disorders (slipped capital femoral epiphysis, Perthes, early avascular necrosis due to other causes). Recognition and treatment of childhood impingement may prevent the evolution to early hip arthritis.

Treatment and outcome of recurrent pelvic chondrosarcoma.

Little has been published about the outcome of patients with recurrent chondrosarcoma of the pelvis. The current study is a review of patients with surgically treated locally recurrent pelvic chondrosarcoma at one institution. Twenty-one patients had surgical resection of recurrent pelvic chondrosarcoma between July 1974 and July 1996. There were nine women and 12 men with a mean age of 46 years (range, 24–67 years) at first recurrence. Patients were followed up for a minimum of 3.3 years and median of 12 years from first (index) recurrence or until death. The mean time to index recurrence was 27 months (range, 5–87 months). In three cases (14%), the tumor at index recurrence was a higher grade than the initial lesion. There were six additional tumors that became a higher grade during subsequent recurrences. Fifteen of the 21 patients (71%) had a second local recurrence. Five patients (24%) had distant metastasis. At death or final followup, 11 patients (52%) had no evidence of disease, two patients (10%) are alive with disease, and eight patients (38%) died of their disease. The three patients with high-grade tumors at index recurrence all died of disease. The treatment of recurrent pelvic chondrosarcoma is a challenging problem. Tumor-free margins may require radical surgery, and the best chance of cure is at the time of initial resection. With aggressive surgical intervention, approximately 50% of patients with recurrent pelvic chondrosarcoma can achieve long-term survival.

Advanced containment methods for Legg-Calvé-Perthes disease: Results of triple pelvic osteotomy

Background Although surgical containment has become a mainstay for the treatment of Legg-Calvé-Perthes (LCP) disease; traditional operations (varus osteotomy of femur, Salter osteotomy) have certain limitations, sometimes resulting in a prolonged limp or inadequate containment. This paper presents the surgical method and results of triple pelvic osteotomy for containment treatment of LCP disease. Methods This retrospective review of 39 children (40 hips; age 5 to 13 y) with LCP disease treated with triple pelvic osteotomy (1995 to 2005) included preoperative lateral pillar assessment and other measurements. Final follow-up films (minimum 3 y, range 3 to 9 y) were assessed using the modified Stulberg classification. Clinical follow-up evaluation assessed limp, limb-length inequality, range of motion, and activity level. Results Twenty-one (53%) hips were graded as lateral pillar B and 19 (48%) were lateral pillar C. Four patients required further treatment before the final follow-up. At final follow-up, 42% had a good outcome (Stulberg I/II), 47% had a fair outcome (Stulberg III), and 11% had a poor outcome. Thus, 89% of patients had satisfactory (good or fair) results. There was a significant difference in outcome based on the preoperative lateral pillar, with B hips more likely to have a good outcome (65%) compared with lateral pillar C hips (12.5%) (P=0.002). There were no lateral pillar B patients with a poor outcome. Seventeen percent of the lateral pillar C patients more than or equal to age 8 had a poor outcome compared with 50% being more than age 8 with a poor outcome. Four patients (3 lateral pillar C, 1 lateral pillar B) required further surgery. Conclusions Triple pelvic osteotomy resulted in maintenance of head shape in lateral pillar B patients of all ages and in younger lateral pillar C patients. Lateral pillar C patients over age 8 were more difficult to treat, however, we still advise containment for these cases because methods are now available to deal with containment failure. Triple pelvic osteotomy is an effective treatment method for LCP patients with lateral pillar B disease and younger patients with lateral pillar C disease. This method provides effective containment, which allows prolonged remodeling while avoiding the limitations of femoral varus osteotomy (limp, short limb) and Salter osteotomy (incomplete containment). Level of Evidence Level IV.

Biomechanical analysis of single screw fixation for slipped capital femoral epiphysis: are more threads across the physis necessary for stability?

Purpose: To evaluate single screw fixation stability, in the treatment of slipped capital femoral epiphysis, as a function of screw thread distribution across the physis. Study Design: In vitro biomechanical study. Methods: Thirty porcine proximal femurs were sectioned through the physeal line and stabilized with a cannulated 7.3-mm stainless steel AO screw. The distal 16 mm of each screw was threaded (5 threads). The femurs were randomized into 5 groups (1, 2, 3, 4, or 5 threads across the physis) and biomechanically tested to determine failure load (N) and stiffness (N/mm). Results: Femurs with 2 or 3 threads across the physis had a significantly greater load to failure and stiffness compared with femurs with 1, 4, or 5 threads across the physis (P < 0.05). Conclusions: Thread distribution across the physis seems to be important. When using screws with a 16-mm thread, greatest strength and stiffness are achieved when 40%-60% of threads engage the epiphysis, with a significant decrease when greater than 80% of threads cross the physis. Too few threads in the epiphysis as well as too few in the metaphysis both lead to decreased stability. Clinical Relevance: This study challenges the belief that compression across the physis maximizes slipped capital femoral epiphysis fixation stability. We recommend equal distribution of threads across the physis when using 16-mm thread screws, and we postulate that screws with a greater thread length (32 mm or fully threaded) would increase fixation stability even further. Optimizing purchase may decrease the incidence of slip progression, especially as the prevalence of obesity increases in the adolescent population.

Intraoperative electromyographic monitoring during periacetabular osteotomy.

Periacetabular osteotomy has become the procedure of choice in many centers for the treatment of symptomatic hip dysplasia. Intraoperative real-time nerve monitoring has been advocated during acetabular fracture repair and complex total hip arthroplasties to prevent iatrogenic sciatic nerve injury. To the authors’ knowledge there is no information concerning the use of intraoperative electromyographic monitoring during periacetabular osteotomy. The purpose of the current study was to investigate the use of intraoperative continuous electromyographic monitoring during periacetabular osteotomy in a relatively large consecutive series of patients as a mechanism to prevent nerve injury during surgery and as a prognostic indicator of neurologic function after periacetabular osteotomy. From September 1992 to July 1999, 140 consecutive periacetabular osteotomies were done in 127 patients at the authors’ institution. There were 96 females and 31 males, with an average age of 32 years at the time of surgery. All patients had intraoperative electromyographic monitoring of femoral and sciatic innervated muscles. All patients were followed up for a minimum of 1 year, until complete resolution of neurologic deficits, or both. Thirty-six patients (26%) had abnormal electromyographic activity recorded during surgery. Seven patients (5%) had peroneal nerve deficits postoperatively including extensor hallucis longus and tibialis anterior weakness with loss of sensation in the first web space. Abnormal electromyographic activity was observed intraoperatively in five of the seven patients with postoperative deficits. Six of the seven injuries resolved completely. One patient with intraoperative electromyographic activity (0.7%) had a postoperative foot drop that persisted for greater than 1 year. There were no femoral, tibial, or obturator nerve deficits observed. Electromyographic monitoring appears to provide prediction of postoperative neurologic deficit.

Biomechanical Comparison of Fully and Partially Threaded Screws for Fixation of Slipped Capital Femoral Epiphysis

Background: Previous data have shown that an equal number of threads on each side of the physis maximizes stability for slipped capital femoral epiphysis (SCFE) fixation. The purpose of the current study was to determine if a fully threaded cancellous screw provides greater stability compared with a partially threaded screw in a porcine model. Methods: Twenty skeletally immature porcine femurs were sectioned, and a 30-degree angular wedge was resected from the femoral neck to simulate SCFE. Femora were randomly assigned to partially threaded (16 mm) or fully threaded screw groups (n = 10/group). Kirschner wires were inserted in a retrograde fashion to stabilize the proximal fragment. Each 7.3-mm-diameter screw was placed using fluoroscopic guidance to obtain 3 threads crossing the physis. Specimens were fixed in custom fixation rigs, and the epiphyseal fragment was loaded at 0.5 mm/s in a posterior-inferior direction to simulate slip progression. Data for displacement (in millimeters) and force (in newtons) were collected for the entire test. Forces at 2, 4, 6, and 8 mm of fragment displacement were compared between groups using a 1-way analysis of variance (p < 0.05). Results: Increasing epiphyseal displacements were associated with incremental increases in loading. There were no significant differences between fully threaded or partially threaded screws for loads at each displacement. Each stepwise increase in displacement was associated with approximately 325 N of force. Conclusion: There was no biomechanical benefit when using a fully threaded screw for stabilization of an in vitro SCFE model. Clinical Relevance: Although there were no differences between screw types in an in vitro model, bone healing around the fully threaded screw may eventually provide greater stability. The use of fully threaded screw remains a reasonable option in the treatment of SCFE, and implant removal may be easier with such a system. Further studies are warranted to verify these 2 points.

Pediatric radial neck fractures: when and how to fix.

This is a review of current evaluation and treatment recommendations for pediatric radial neck fractures, including a series of cases that were presented and reviewed by a panel at The Pediatric Orthopedic Society of North America annual meeting 2010. We summarize the different published techniques for closed, percutaneous, and open reduction, and review when these techniques are recommended. The potential complications that can arise from radial neck fractures and their treatment are discussed.