Does obesity influence the outcome after the operative treatment of ankle fractures?

Many orthopaedic surgeons believe that obese patients have a higher rate of peri-operative complications and a worse functional outcome than non-obese patients. There is, however, inconsistency in the literature supporting this notion. This study was performed to evaluate the effect of body mass index (BMI) on injury characteristics, the incidence of complications, and the functional outcome after the operative management of unstable ankle fractures. We retrospectively reviewed 279 patients (99 obese (BMI > or = 30) and 180 non-obese (BMI < 30) patients who underwent surgical fixation of an unstable fracture of the ankle. We found that obese patients had a higher number of medical co-morbidities, and more Orthopaedic Trauma Association type B and C fracture types than non-obese patients. At two years from the time of injury, however, the presence of obesity did not affect the incidence of complications, the time to fracture union or the level of function. These findings suggest that obese patients should be treated in line with standard procedures, keeping in mind any known associated medical co-morbidities.

Fixation of periprosthetic femoral shaft fractures: a biomechanical comparison of two techniques.

OBJECTIVE: To determine which of two currently used techniques for the treatment of periprosthetic femoral shaft fractures provides the greater fixation rigidity and strength. DESIGN: A laboratory study using six matched pairs of femurs. METHODS: Embalmed femur prosthesis constructs had a simulated periprosthetic fracture created and were fixed with a plate with proximal cables and distal bicortical screws (Ogden concept) or two allograft struts and cables. Fixation stability was compared in various loading modalities before and after cycling. They were then tested to failure. OUTCOME MEASUREMENTS: Fixation rigidity was defined as the ratio of applied load to the amount of displacement at the fracture. RESULTS: In all loading modalities, the Ogden construct was more rigid than the allograft strut fixation. The Ogden construct required 1,295 newtons for failure and the allograft strut fixation required 950 newtons (p < 0.05). CONCLUSION: The Ogden construct provided a more rigid and stronger initial fixation of a periprosthetic fracture than did the allograft construct.

Effect of articular step-off and meniscectomy on joint alignment and contact pressures for fractures of the lateral tibial plateau.

OBJECTIVES: To determine the effects of intraarticular step-off and lateral meniscectomy on the alignment of the articular axis, contact area, and pressures for lateral tibial plateau fractures. DESIGN: Biomechanical cadaver study. INTERVENTION: Six fresh cadaveric knees were used. A simulated split fracture of the lateral tibial plateau was reproducibly created by osteotomies, and articular step-offs of zero, one, two, four, and six millimeters were achieved by using support shims. The knee was loaded with 500 newtons in 0 degrees and 350 newtons in 30 degrees of flexion. A digital camera determined changes in the alignment of the articular axis, and F-Scan sensors were inserted into the medial and lateral joint compartments to determine the pressures and pressure distributions. MAIN OUTCOME MEASUREMENT: Each specimen was tested at step-offs of zero, one, two, four, and six millimeters, with the presence or absence of the lateral meniscus. The changes in alignment of the articular axis, the contact area, and the average and maximum contact pressures for each condyle were obtained. RESULTS: Increased articular step-off heights progressively increased valgus angulation and average and maximum contact pressures and progressively decreased contact areas in lateral compartment. At a six-millimeter step-off with 0 degrees of flexion, the valgus angle increased an average of 7.6 degrees, and average contact pressures and maximum contact pressures increased an average of 208 percent and 97 percent, respectively, and contact area decreased an average of 33 percent (p < 0.05). Meniscectomy increased valgus angles by an average of 38 percent and contact pressures by an average of 45 percent and decreased contact areas by 26 percent in the lateral compartment at the same articular step-off heights (p < 0.05). CONCLUSION: The results of this study show the importance of decreasing articular step-off heights in treating lateral tibial plateau split fractures, particularly if a meniscectomy is performed.

Efficacy of preoperative skin traction in hip fracture patients: a prospective, randomized study.

OBJECTIVE: To compare the analgesic benefit of preoperative skin traction with the placement of a pillow under the injured extremity in patients with hip fractures. DESIGN: Prospective, randomized clinical study. SETTING: University-affiliated teaching institution. PATIENTS AND PARTICIPANTS: One hundred consecutive patients with hip fractures admitted to the authors' institution who met inclusion criteria were enrolled. Fifty-five patients had femoral neck fractures, and forty-five patients had intertrochanteric fractures. The average patient age was seventy-eight years. INTERVENTION: All patients were preoperatively randomized into two intervention groups. One group underwent placement of five pounds of skin traction on the injured extremity, whereas the second underwent placement of a pillow under the injured extremity. Fifty patients were enrolled in each intervention group. RESULTS: With respect to immediate postintervention pain levels, patients treated with a pillow showed a trend toward better pain relief, as compared with patients treated with skin traction; however, this was not statistically significant. On the morning after admission, patients treated with a pillow had a statistically significant greater reduction in pain (p = 0.04). These patients also requested a statistically significant lower amount of pain medication (p < 0.01). CONCLUSIONS: The authors think that preoperative skin traction in patients with hip fractures does not provide significant pain relief, as compared with pillow placement under the injured extremity, and thus should not be routinely performed in this patient population for analgesia.

Outcome after hip fracture in individuals ninety years of age and older.

OBJECTIVE: To assess outcome after hip fracture in patients ninety years of age and older, as compared with a population of the same age and sex in the United States and younger patients with hip fractures. DESIGN: Prospective, consecutive. SETTING: University teaching hospital. METHODS: Eight hundred fifty community-dwelling elderly people who sustained an operatively treated hip fracture were prospectively followed up. MAIN OUTCOME MEASUREMENTS: The outcomes examined in this study were the patients' in-hospital mortality and postoperative complication rates, hospital length of stay, discharge status, mortality rate, place of residence, ambulatory ability, and independence in basic and instrumental activities of daily living twelve months after surgery. RESULTS AND CONCLUSIONS: The mean patient age was 79.7 years (range 65 to 105 years). Seventy-six (8.9 percent) patients were ninety years of age and older. Patients who were ninety years of age and older had significantly longer mean hospital lengths of stay than younger individuals (p = 0.01). People ninety years of age and older were more likely to die during the hospital stay (p = 0.001) and within one year of surgery (p = 0.001). Patients who were ninety years of age and older were more likely to have a decrease in their basic activities of daily living status (p = 0.03) and ambulation level (p = 0.01). Younger individuals had a higher standard mortality ratio (1.48) than did patients who were ninety years of age and older (1.24). Being ninety years of age and older was not predictive of having a postoperative complication, of being placed in a skilled nursing facility at discharge or at one-year follow-up, or recovering of prefracture independence in instrumental activities of daily living.

Effect of piriformis versus trochanteric starting point on fixation stability of short intramedullary reconstruction nails.

Recently, a new, shorter IM nail using two 6 mm reconstruction screws for proximal fixation was introduced in two versions for femoral insertion: piriformis fossa (FAN) and greater trochanter (TAN). These nails were compared experimentally for their fixation stability, proximal load transmission, and failure strength in an unstable intertrochanteric fracture model in cadaveric femurs. Vertical and axial loads were first applied to the intact femurs. Fractures were created, subsequent fixation applied, and the femurs underwent a series of both vertical and axial loading tests. There was no significant difference in strain readings between the nails for either axial loading or cyclical loading. There was no statistically significant difference between the loads to failure for the trochanteric nails and the standard antegrade nails. The average ultimate loadfor the FAN and TAN nails were 3010 N and 2830 N respectively. These two nails performed very similarly throughout our testing.

The effect of screw type on the fixation of depressed fragments in tibial plateau fractures.

The ability of various screw types to stabilize depressed tibial plateau fractures was determined in a biomechanical study using a Sawbones model. Two sizes of both cancellous and cortical screws were evaluated for both supportfrom below and through the depressed fragment. As a general trend, cancellous bone screws provided a greater resistance to fragment displacement than cortical bone screws, and screws with a smaller thread diameter provided greater resistance to displacement than screws of the same thread type with a larger diameter. These results agree with the accepted standard that cancellous screws provide better fixation for tibial plateau fractures, but also are counterintuitive in that smaller screws provided greater fixation than larger screws of the same type.

The effect of distal screw orientation on the intrinsic stability of a tibial intramedullary nail.

To compare the intrinsic stability of two distal interlocking screw orientations for tibial nailing of distal third tibial diaphyseal fractures without isthmal support, six Depuy (Warsaw, Indiana) tibial intramedullary nails were implanted in simulated distal tibiae. The constructs received both two parallel (medial to lateral) and two perpendicular (one medial to lateral, one anterior to posterior) distal interlocking screws in a random order Angular, translational, and torsional displacements of the nails were measured in response to 70 N proximal applications of anterior, posterior, medial, and lateral loads, and a 7.7 Newton-meter torsional load. There were no differences in medial or lateral angulations between the screw orientations (average: 2.5 degrees, p > 0.8). Angulation in the sagittal plane (anterior and posterior) was slightly less for parallel screw fixation (1.6 degrees versus 2.4 degrees), but this was not statistically significant (p > 0.1). Rotational angulation was higher in the parallel (average: 9.9 degrees) versus the perpendicular (average: 8.1 degrees) screw orientation, but these results were not statistically significant (p > 0.1). Pure translation did not occur in either the parallel or perpendicular screw orientations. These results indicate that fixation stability of these tibial intramedullary nails is not significantly influenced by distal interlocking screw orientation in response to sagittal, coronal, or rotational forces.

Soft-tissue principles for orthopaedic surgeons.

Meticulous handling of the tissues, reversal of known patient risk factors, and attention to detail can avoid many soft-tissue complications. Prompt management or consultation of a soft-tissue expert may reduce the morbidity and need for extensive reconstructive procedures.

Robotics and computer-assisted orthopaedic surgery.

These are just a few representative applications of the synergistic use of computer and robotic technology assisting the orthopaedic surgeon. While the individual systems are certain to change over time, the basic principles of correlating radiographic and anatomic data through a registration process, and displaying additional instrument or implant information through smart tools and surgical navigation are certain to become an increasingly important aspect of joint arthroplasty, deformity correction, and spinal and trauma surgery. Only the orthopaedic surgeon who clearly understands the goals, applications, and limitations of these systems can decide which are appropriate for his patients, his hospital, and his practice. Determining the cost and time benefits, both before and after an obligatory "learning curve" requires a complex interaction of capital investments, time savings, and outcome research on both safety and efficacy issues. The orthopaedist who understands and applies these technologies will help his patients to achieve the best possible care. Excellent resources in the literature on this topic include the September, 1998, issue of Clinical Orthopaedics and Related Research, a symposium on "Computer-Assisted Orthopaedic Surgery: Medical Robots and Image Guided Surgery"; Guest editor, Anthony M. DiGioia, III, MD. Also, the January, 2000, issue of Operative Techniques in Orthopaedics, "Medical Robotics and Computer-Assisted Orthopaedic Surgery. Guest editors: Anthony M. DiGioia, III, M.D. and Branislav Jaramaz, Ph.D. Additional Internet based information is available from the Journal of Computer Aided Surgery (formerly: Journal of Image Guided Surgery), at http://journals.wiley.com/.

The effects of diabetes on outcome after hip fracture.

Recent studies have suggested that patients with a history of diabetes undergoing hip fracture stabilization have higher rates of morbidity and mortality as well as poorer functional results than control groups of non-diabetics. This study was performed to evaluate the effect of diabetes on patient outcome after hip fracture. Between July 1987 and December 1996, 849 community dwelling elderly who sustained an operatively treated hip fracture were prospectively followed to determine the effect of diabetes on patient outcome. The predictor variable was the presence or absence of diabetes mellitus. Ninety-three patients (11%) had a history of diabetes. Diabetic patients were more dependent in activities of daily living and ambulation prior to hip fracture. The presence of diabetes mellitus also increased the likelihood of a patient dying during hospitalization, but had no effect on recovery of ambulatory ability or activities of daily living. Although diabetic patients have increased in-hospital mortality when compared to non-diabetic patients, patients with diabetes are just as likely to recover pre-fracture functional status as non-diabetic patients.

A biomechanical comparison of Schuhli nuts or cement augmented screws for plating of humeral fractures.

Schuhli locking nuts can be used in poor quality cortical bone to enhance fixation stability as an alternative to cement augmented screws. This study compared the fixation strength and stability of plate constructs using Schuhli locking nuts with standard screws and cement augmented screws for fixation of simulated humeral shaft fractures in a test model with osteoporosis. The constructs were tested in axial compression, 4-point bending, and torsion to determine fixation stability. The humeri were cycled in torsion (4.5 Nm) for 1000 cycles to simulate upper extremity use during the early postoperative period and retested for stability. The Schuhli locking nuts and cement augmented screws had significantly greater fixation stability than the standard screws before (range, 6-14 times greater) and after cycling in torsional loading (range, 3-3.6 times greater). Although cement augmented screws and Schuhli augmentation showed increased fixation stability compared with the standard screws in axial and 4-point bending before cycling (range, 1.3-1.4 times greater), this was not significant. Compared with Schuhli fixation, cement augmented screws showed no significant difference in fixation stability in all loading modes before and after cycling. Schuhli locking nuts offer the stability of cement augmentation while avoiding its potential adverse effects on fracture healing with extravasation and thermal necrosis.

Effect of previous cerebrovascular accident on outcome after hip fracture.

OBJECTIVE: To evaluate the effect of previous cerebrovascular accident on outcome after hip fracture. STUDY DESIGN: Prospective, consecutive. PATIENTS: From July 1987 to March 1997, 862 community-dwelling patients sixty-five years of age or older who had sustained an operatively treated femoral neck or intertrochanteric fracture were prospectively followed. INTERVENTION: All patients had operative fracture treatment. MAIN OUTCOME MEASUREMENTS: Postoperative complications, in-hospital mortality, hospital length of stay, hospital discharge status, one-year mortality and place of residence, and return to preinjury ambulatory level, basic and instrumental activities of daily living status. RESULTS: Sixty-three patients (7.3 percent) had a history of cerebrovascular accident; the fracture was on the hemiplegic side in forty-six (86.8 percent) of the fifty-three patients with hemiplegia. Patients who had a history of cerebrovascular accident were more likely to be male and have an American Society of Anesthesiologists (ASA) rating of III or IV. They were also more likely to have three or more comorbidities, be a home ambulator, and be dependent on basic and instrumental activities of daily living before hip fracture. Hospital length of stay was significantly higher for patients who had a history of cerebrovascular accident. There were no differences in the incidence of hospital mortality or one-year mortality between patients who did and did not have a history of cerebrovascular accident before hip fracture. In addition, at one-year follow-up, when controlling for prefracture level of function, there were no differences in the rate of functional recovery between the two groups of patients. CONCLUSIONS: The functional recovery of elderly hip fracture patients who had a prior cerebrovascular accident was similar to that of patients who had no history of a prior cerebrovascular accident.

Fixation of periprosthetic femoral shaft fractures occurring at the tip of the stem: a biomechanical study of 5 techniques.

This study evaluated 5 currently used periprosthetic femoral shaft fracture fixation techniques to determine which technique provided the greatest fixation stability. Periprosthetic fractures in 30 synthetic femurs were fixed with a plate with cables, plate with proximal cables and distal bicortical screws (Ogden concept), plate with proximal unicortical screws and distal bicortical screws, plate with proximal unicortical screws and cables and distal bicortical screws, or 2 allograft cortical strut grafts with cables. These specimens were then tested in 3 physiologic loading modes. The plate constructs with proximal unicortical screws and distal bicortical screws or with proximal unicortical screws, proximal cables, and distal bicortical screws were significantly more stable in axial compression, lateral bending, and torsional loading than the other fixation constructs studied.

New technique for treatment of unstable distal femur fractures by locked double-plating: case report and biomechanical evaluation.

BACKGROUND: A comminuted, intra-articular distal femur fracture was surgically treated by the authors with a locked, double-plating technique because fixation stability could not be initially achieved by using a standard double-plating technique. The purpose of this study was to determine biomechanically whether a locked double-plate construct would enhance fixation stability compared with a nonlocked double-plate construct. METHODS: Six matched pairs of mildly osteopenic femurs were selected and all had a reproducible intra-articular fracture pattern created. Each pair underwent fixation with either a double-plating construct or a locked, double-plating construct that was randomly assigned. The instrumented femurs were then mechanically tested in several loading modes to determine fixation stability. After initial testing, specimens were cyclically loaded and retested for stability. RESULTS: The locked, double-plating construct provided significantly greater fixation stability than the standard double-plating construct in precycling and postcycling biomechanical testing. CONCLUSION: The technique described is particularly applicable for severely comminuted fractures of the distal femur and fractures in osteopenic bone with poor screw purchase. It offers a simple alternative for enhancing fixation stability, which avoids the potential complications of methylmethacrylate-enhanced screw fixation.

A functional recovery score for elderly hip fracture patients: I. Development.

OBJECTIVE: To develop a Functional Recovery Score for ambulatory elderly hip fracture patients related to independent functioning to assess restoration of function to prefracture status. STUDY DESIGN/METHODS: The phases of this effort consisted of: (a) identification of five relevant components represented by sixteen specific functional capacities; (b) assessment of the importance independent community-dwelling elderly gave to the sixteen functional capacities; (c) pilot testing of a sixteen-item preliminary questionnaire in recovering elderly hip fracture patients; and (d) modification of the questionnaire to an eleven-item score. RESULTS: The resulting eleven-item Functional Recovery Score is comprised of three main components: basic activities of daily living (BADL) assessed by four items, instrumental activities of daily living (IADL) assessed by six items, and mobility assessed by one item. Basic activities of daily living comprise 44 percent of the score; instrumental activities of daily living comprise 23 percent, and mobility comprises 33 percent. Complete independence in basic and instrumental activities of daily living and mobility results in a score of 100 percent.