Marc W. Hungerford

Deep wound infections after neuromuscular scoliosis surgery : A multicenter study of risk factors and treatment outcomes

Study Design. A retrospective case–control study evaluating risk factors for infection, causative organisms, and results of treatment in patients with cerebral palsy or myelomeningocele who underwent fusion for scoliosis was performed. Objectives. To identify risk factors for infection, and to characterize the infections in terms of infecting organisms and response to treatment. Summary of Background Data. No previous studies have analyzed risk factors or causative organisms, nor have they indicated results of treatment for infections in this group of patients. Methods. After a 10-year retrospective review of 210 surgically treated patients, deep wound infections developed in 16 patients with myelomeningocele and 9 patients with cerebral palsy. These patients were studied extensively for possible risk factors, along with 50 uninfected patients matched for age, diagnosis, and year of surgery. Statistical testing was performed to identify risk factors. The courses of the infections were characterized in terms of organisms isolated and response to treatment. Treatment was performed in a stepwise fashion and classified in terms of the most successful step: debridement and closure, granulation over rods, or instrumentation removal. Results. Of the 10 risk factors tested, 2 were found to be significant: degree of cognitive impairment and use of allograft. Findings showed that 52% of the infections were polymicrobial. Gram-negative organisms were isolated as commonly as gram-positive organisms. The most common organisms were coagulase-negative Staphylococcus, Enterobacter, Enterococcus, and Escherichia coli.— Debridement and closure were successful in 11 of 25 patients with deep wound infection. Of the 14 patients with infection not resolved by serial debridements and closure, 2 were managed successfully by allowing the wound to granulate over rods, and 7 required rod removal for persistent wound drainage. There were three symptomatic pseudarthroses. Infections resulting from gram-positive organisms were most often managed successfully with debridement and closure (P = 0.012). Conclusions. Patients with cerebral palsy or myelomeningocele who have severe cognitive impairment, and those who received allograft may be at increased risk for infection. Infections are more often polymicrobial andcaused by gram-negative organisms than is typical for elective orthopedic procedures. This suggests an enteric source. Treatment with debridement and closure was not always successful. Patients in whom infection develops are then at increased risk for pseudarthrosis.

The Operative Treatment of Peroneal Nerve Palsy

We retrospectively reviewed the results of operative decompression for peroneal nerve palsy in thirty-one patients who had been managed between 1980 and 1990. All patients had been managed non-operatively for at least two months after they had initially been seen. Intraoperatively, we found epineurial fibrosis and bands of fibrous tissue constricting the peroneal nerve at the level of the fibular head and at the proximal origin of the peroneus longus muscle. At a mean of thirty-six months (range, twelve to seventy-two months) postoperatively, thirty (97 per cent) of the thirty-one patients reported subjective and functional improvement and were able to discontinue the use of the ankle-foot orthosis. In contrast, only three of nine patients who had been managed non-operatively reported subjective and functional improvement (p < 0.01). Peroneal nerve palsy does not always resolve spontaneously; if it is left untreated, the loss of dorsiflexion of the ankle and persistent paresthesias can result in severe functional disability. Therefore, if non-operative measures do not lead to improvement within two months, we believe that operative decompression should be considered.

Surface Replacement Hemiarthroplasty for the Treatment of Osteonecrosis of the Femoral Head

We reviewed the results of thirty-three femoral resurfacing procedures in twenty-five patients who had stage-III or early stage-IV osteonecrosis of the femoral head according to the classification system of Ficat and Arlet. There were no perioperative complications. Thirty hip prostheses (91 percent) survived for a minimum of five years. At a mean of 10.5 years (range, four to fourteen years) postoperatively, sixteen (62 percent) of the twenty-six hips with stage-III disease had a good or excellent Harris hip score. Four of the seven hips with stage-IV disease did not have or need a total hip arthroplasty. Overall, twenty hips (61 percent) had a good or excellent result according to the scoring system of Harris, and thirteen (39 percent) had a fair or poor result and subsequently had or needed a total hip arthroplasty. The mean interval between the hemiarthroplasty and the total hip arthroplasty was sixty months (range, thirty-six to 136 months). These thirteen hips all had a successful clinical result (a Harris hip score of at least 80 points) at a mean of thirty months (range, twenty-four to seventy-two months) after the total hip arthroplasty. The results of the present study suggest that resurfacing of the femoral head can be a successful interim procedure for the management of patients who have Ficat and Arlet stage-III or early stage-IV disease with a large lesion that is not amenable to other treatment options except total hip arthroplasty.

Basal Closing Wedge Osteotomy for Correction of Hallux Valgus and Metatarsus Primus Varus: 10- to 22-Year Follow-up

Between 1974 and 1985, 59 patients (83 feet) underwent basal closing wedge osteotomy in combination with a bunionectomy and a lateral soft tissue release for correction of hallux valgus and metatarsus primus varus at this institution. Of the original 59 patients, 42 patients (60 feet) with at least 10 years of follow-up (average, 194 months; range, 144–266 months) were available for this study. Results were analyzed by review of the medical records and plain radiographs, a standardized clinical questionnaire, and physical examination. Of the 60 feet, patients rated outcomes as excellent or good in 51 feet (85%) and rated cosmesis as excellent or good in 44 feet (73%). Radiographically at final follow-up, hallux valgus and intermetatarsal angles averaged 19.9° (range, 0–40°) and 6.7° (range, 0–18°), respectively. The sesam-oid position was corrected from an average preoperative grade of 2.6 to a grade of 0.9 at final follow-up. The average shortening of the first metatarsal was 5 mm. The disadvantages of the closing wedge osteotomy are that it is technically demanding and it entails the risk of shortening, dorsal malalignment, and metatarsalgia. In the current study, long-term complications included hallux varus deformity (16 feet), dorsal malalignment (15 feet), and metatarsalgia (14 feet). Despite good correction of the intermetatarsal angle and sesamoid position, the clinical results and the incidence of complications after basal closing wedge osteotomy were not as favorable as those reported for other procedures in the literature. Therefore, alternative procedures, such as the basal crescentic osteotomy or the basal chevron osteotomy, should be used.

AVASCULAR NECROSIS OF THE TALUS TREATED BY CORE DECOMPRESSION

We reviewed 11 patients (17 ankles) who had had core decompression for symptomatic avascular necrosis of the talus before collapse. The Mazur grading system was used to assess function preoperatively and at final follow-up, and radiographs were graded according to the Ficat and Arlet (1980) classification modified for the ankle. At a mean follow-up of seven years (2 to 14) 14 ankles (82%) had an excellent or good outcome (Mazur scores > 80 points; pain scores > 40 points (41 to 50). The other three ankles required tibiotalar fusion at a mean of 13 months (5 to 20) after core decompression. We conclude that core decompression is a viable method of treatment for symptomatic avascular necrosis of the talus before collapse.

Lateral femoral cutaneous nerve impairment after direct anterior approach for total hip arthroplasty.

The anterior supine approach for total hip arthroplasty (THA) offers the advantage of operating through a true intravascular and intranervous plane, but it places the lateral femoral cutaneous nerve at risk. The purpose of this study was to identify the incidence of and impairment relating to injury of the lateral femoral cutaneous nerve. We performed a retrospective chart review of 81 hips undergoing anterior supine THA from November 2005 through May 2007 to determine operative time, estimated blood loss, fluoroscopic time, type of anesthesia used, intraoperative complications, and postoperative systemic and wound complications. Postoperative radiographs were evaluated for leg-length discrepancy, acetabular inclination and anteversion, and femoral stem position. Patients were reassessed at 6 weeks, 3 months, 6 months, 1 year, and 2 years. At each visit, patients were questioned about numbness or paresthesias in the distribution of the lateral femoral cutaneous nerve; if present, the patient outlined the area with a marking pen. This area was photographed, and data were collected. No hip had frank numbness; 12 hips (14.8%) had paresthesias. For those 12, symptoms resolved in 4 by 6 months, in 6 by 1 year, and in 10 (83.3%) by 2 years; 2 remained unresolved. No significant difference was found between patients with and without paresthesias or between patients with resolved or unresolved paresthesias. Impaired sensation did not appear to affect functional outcome or Harris Hip Score. Incision position, dissection plane, retractor placement, tension and soft tissue handling, and surgeon experience may affect incidence of injury to the lateral femoral cutaneous nerve.

Modified Austin Procedure for Correction of Hallux Valgus

The Austin osteotomy is a widely accepted method for correction of mild and moderate hallux valgus. In view of publications by Kitaoka et al. in 1991 and by Mann and colleagues, a more radical lateral soft tissue procedure was added to the originally described procedure. From September 1992 to January 1994, 85 patients underwent an Austin osteotomy combined with a lateral soft tissue procedure to correct their hallux valgus deformities. Seventy-nine patients (94 feet) were available for follow-up. The average patient age at the time of the operation was 47.1 years, and the average follow-up was 16.2 months. The average preoperative intermetatarsal angle was 13.9°, and the average hallux valgus angle was 29.7°. After surgery, the feet were corrected to an average intermetatarsal angle of 5.8° and an average hallux valgus angle of 11.9°. Sesamoid position was corrected from 2.1 before surgery to 0.5 after surgery. The results were also graded according to the Hallux Metatarsophalangeal Interphalangeal Score, and the functional and cosmetic outcomes were graded by the patient. Dissection of the plantar transverse ligament and release of the lateral capsule repositioned the tibial sesamoid and restored the biomechanics around the first metatarsophalangeal joint. There was no increased incidence of avascular necrosis of the first metatarsal head compared with the original technique.

Learning curve for the anterior approach total hip arthroplasty.

The anterior approach to total hip arthroplasty has the advantages of using intermuscular and internervous planes, but it is technically demanding. We evaluated the learning curve for this approach with regard to operative parameters and immediate outcomes. From November 2005 through May 2007, 73 patients underwent 81 consecutive primary anterior-approach total hip arthroplasties. We grouped the hips into three consecutive groups of 20 and one of 21, and surgical and fluoroscopy times, estimated blood loss, intraoperative and postoperative complications, patient comorbidities, component position, and leg-length discrepancy were compared (statistical significance, p < 0.05). Comparing Groups 1 and 4, there were only two significant differences: operative time, 124 to 98 minutes, respectively, and estimated blood loss, 596 to 347 mL, respectively. Proficiency improved after Group 2 (40 cases) and was more marked after Group 3 (60 cases), with no major complications. Surgeons considering this approach should expect a substantial learning period.

Trochanteric Bursitis After Total Hip Arthroplasty: Incidence and Evaluation of Response to Treatment

We examined the efficacy of corticosteroid injection as treatment for postarthroplasty trochanteric bursitis and the risk factors for failure of nonoperative treatment. There were 32 (4.6%) cases of postsurgical trochanteric bursitis in 689 primary total hip arthroplasties. Of the 25 hips with follow-up, 11 (45%) required multiple injections. Symptoms resolved in 20 (80%) but persisted in 5. We found no statistically significant differences between patients who did and did not develop trochanteric bursitis, or between those who did and did not respond to treatment. There was a trend toward younger age and greater limb-length discrepancy in nonresponders. In conclusion, (1) corticosteroid injection(s) for postoperative trochanteric bursitis is effective; and (2) nonoperative management may be more likely to fail in young patients and those with leg-length discrepancy.

Therapie der Osteonekrose

ZusammenfassungDie Therapie der ON beinhaltet unterschiedliche Verfahren für ein breites Spektrum verschiedener radiologischer Stadien. Für Frühformen im Präkollapsstadium mit kleinen bis mittelgroßen Läsionen kann der Einsatz von Medikamenten oder die Hüftkopfentlastungsbohrung empfohlen werden. Von verschiedenen Autoren wurden für die kleinen bis mittelgroßen Läsionen unterschiedliche Osteotomien eingesetzt, die jedoch mäßige Ergebnisse zeigten. Im Postkollapsstadium mit kleinen bis mittelgroßen Läsionen können die verschiedenen Techniken der Knochentransplantation empfohlen werden. Diese Eingriffe sollten jedoch immer mit der Inspektion des Knorpels verbunden werden um große Läsionen oder Knorpelschäden auszuschließen. In diesen Fällen ist der Einsatz einer Oberflächenersatzprothese des Femurkopfes sinnvoll. Bei bereits bestehendem Knorpelschaden am Acetabulum sollte jedoch primär eine konventionelle Hüfttotalendoprothese eingesetzt werden.In der Zukunft können mit den neu entwickelten Polyethylengleitflächen, durch die Verwendung von Keramik-Keramik- oder anderen Gleitpaarungen hoffentlich längere Überlebenszeiten der Totalendoprothesen erzielt werden. Eine weitere Verbesserung könnte der Einsatz von Metall-Metall-Gleitpaarungen sowohl bei den Oberflächenersatzendoprothesen als auch bei den konventionellen Hütftotalendoprothesen bringen.Des Weiteren könnte in Zukunft durch den zusätzlichen Einsatz von bioaktiven Substanzen bei allen gelenkerhaltenden Eingriffen, von der Hüftkopfentlastungsbohrung, über die Osteotomien bis zu den Knochentransplantationen Verbesserungen erzielt werden. Diese bioaktiven Faktoren beinhalten osteoinduktive Zytokine, Stimulationsfaktoren für die Gefäßneubildung sowie Knochenwachstumsfaktoren. Darüber hinaus könnten osteokonduktive Substanzen hilfreich sein und mit osteoinduktiven Faktoren kombiniert werden. Diese bioaktiven Substanzen werden in einem anderen Kapitel dieses Themenheftes ausführlicher besprochen. Im neuen Millennium besteht die berechtigte Hoffnung, dass sich die bisherigen Ergebnisse bei der Behandlung der ON deutlich verbessern lassen.SummaryThe treatment of osteonecrosis of the femoral head involves a continuum based on a radiographic spectrum of disease. Core decompression or pharmacological agents can be utilized for the earliest small or medium-sized pre-collapsed lesions. For these types of lesions, osteotomy has been tried by various authors with moderate success. For small or medium lesions that are post-collapse, various bone grafting procedures have been used. This approach should be tempered with a look at the articular cartilage if this is damaged or the lesion is large. Limited femoral resurfacing can be used for hips that do not have acetabular involvement. If there is acetabular involvement, total hip replacement remains the treatment of choice.There are present innovations in total hip arthroplasty that hopefully will lead to increased longevity of these prostheses with newer polyethylenes as well as the use of ceramic and other types of interfaces. Another possible advance for this disease would be the use of metal on metal standard prostheses, as well as metal on metal resurfacing arthroplasties. In terms of a salvage of the femoral head, all of the different procedures – core decompression, osteotomy, bone grafting – can be enhanced by new advances in the development of the utilization of bioactive factors. These range from osteoinductive agents such as cytokines, angiogenic stimulating factors, and bone morphogenetic proteins.In addition, osteoconductive substances may be helpful and can be combined with osteoinductive substances. These bioactive factors are described in detail in another chapter of this issue. With the ushering in of the millennium, there is hope for better results with this disease.