Laura W. Lewallen

Predictors of Recurrent Instability After Acute Patellofemoral Dislocation in Pediatric and Adolescent Patients

Background: Patellofemoral instability is common in the pediatric and adolescent population, yet prognosis after the first dislocation has been difficult to determine. Purpose: To describe the demographics of pediatric and adolescent patients with a first-time patellofemoral dislocation and to determine predictors of recurrent instability. Study Design: Case-control study; Level of evidence, 3. Methods: A search of the Mayo Medical Index database between 1998 to 2010 was performed, and 2039 patients were identified. Inclusion criteria were (1) age 18 years or younger, (2) no history of patellofemoral subluxation/dislocation of the affected knee, (3) radiographs within 4 weeks of the initial instability episode, and (4) a dislocated patella requiring reduction or convincing history/findings suggestive of acute patellar dislocation (effusion/hemarthrosis, tenderness along medial parapatellar structures, and apprehension with lateral patellar translation). Radiographs were evaluated for trochlear dysplasia (Dejour classification) and patella alta (Caton-Deschamps and Insall-Salvati indices). Skeletal maturity was graded based on the distal femoral and proximal tibial physes (open, closing, or closed). Results: A total of 222 knees (120 male [54.1%] and 102 female [45.9%]) in 210 patients with an average age of 14.9 years (range, 9-18 years), met the inclusion criteria. Twenty-four patients (10.8%) underwent early surgery. All others were initially treated nonoperatively. Of the 198 patients in this group, 76 (38.4%) had recurrent instability, and 39 (51.3%) of these required surgical treatment. Recurrent instability was associated with trochlear dysplasia (P < .01). Patients with both immature physes and trochlear dysplasia had a recurrence rate of 69% (33/48), with a hazard ratio of 3.3. Age, sex, body mass index, and patella alta were not statistically associated with recurrent instability. Conclusion: Nonoperative treatment for first-time patellofemoral dislocation resulted in a 62% success rate. However, skeletally immature patients with trochlear dysplasia had only a 31% success rate with nonoperative management. Nearly half of patients with recurrent instability required surgical intervention to gain stability.

Diabetes Mellitus, Hyperglycemia, Hemoglobin A1C and the Risk of Prosthetic Joint Infections in Total Hip and Knee Arthroplasty

Diabetes mellitus is an established risk factor for infections but evidence is conflicting to what extent perioperative hyperglycemia, glycemic control and treatment around the time of surgery modify the risk of prosthetic joint infections (PJIs). In a cohort of 20,171 total hip and knee arthroplasty procedures, we observed a significantly higher risk of PJIs among patients with a diagnosis of diabetes mellitus (hazard ratio [HR] 1.55, 95% CI 1.11, 2.16), patients using diabetes medications (HR 1.56, 95% CI 1.08, 2.25) and patients with perioperative hyperglycemia (HR 1.59, 95% CI 1.07, 2.35), but the effects were attenuated after adjusting for body mass index, type of surgery, ASA score and operative time. Although data were limited, there was no association between hemoglobin A1c values and PJIs.

First-Time Patellofemoral Dislocation: Risk Factors for Recurrent Instability.

Patellofemoral instability is a complex problem, which can be difficult to manage. The purpose of this study was to describe the demographics of patients with a first-time patellofemoral dislocation, and identify risk factors for recurrent instability. This was a single institution, institutional review board-approved, retrospective review of >2,000 patients with a patellar dislocation between 1998 and 2010. Inclusion criteria are as follows: (1) no prior history of patellofemoral subluxation or dislocation of the affected knee; (2) X-rays within 4 weeks of the initial instability episode; and (3) a dislocated patella requiring reduction, or history/findings suggestive of acute patellar dislocation (effusion/hemarthrosis, tenderness along the medial parapatellar structures, and apprehension with lateral patellar translation). Clinical records and radiographs were reviewed. The Caton-Deschamps and Insall-Salvati indices were used to evaluate patella alta. Trochlear dysplasia was assessed using the Dejour classification system. Skeletal maturity was graded based on the distal femoral and proximal tibial physes, using one of the following categories: open, closing, or closed. Three hundred twenty-six knees (312 patients) met the aforementioned criteria. There were 145 females (46.5%) and 167 males (53.5%), with an average age of 19.6 years (range, 9-62 years). Thirty-five patients (10.7%) were treated with surgery after the initial dislocation. All others were initially managed nonoperatively. Of the 291 patients managed nonoperatively, 89 (30.6%) had recurrent instability, 44 (49.4%) of which eventually required surgery. Several risk factors for recurrent instability were identified, including younger age (p < 0.01), immature physes (p < 0.01), sports-related injuries (p < 0.01), patella alta (p = 0.02), and trochlear dysplasia (p < 0.01). Sixty-nine percent of patients with a first-time patellofemoral dislocation will stabilize with conservative treatment. However, patients younger than 25 years with trochlear dysplasia have a 60 to 70% risk of recurrence by 5 years. This information is helpful when counseling patients on their risk for recurrent instability and determining the most appropriate treatment plan. The clinical tool shown in Fig. 4 may be especially useful.

Clinical Outcome of Internal Fixation of Unstable Juvenile Osteochondritis Dissecans Lesions of the Knee

Juvenile osteochondritis dissecans (OCD) lesions of the knee are a common cause of knee pain in skeletally immature patients.The authors sought to determine lesion healing rates, the risk factors associated with failure to heal, and the clinical outcomes for patients who underwent internal fixation for unstable OCD lesions. A retrospective review was conducted of all patients who underwent internal fixation of OCD lesions from 1999 to 2009. Using validated scoring systems, clinical outcome and functional activity were evaluated at the follow-up. The study group comprised 19 patients (20 knees). Mean patient age was 14.5 years (range, 12-17 years). Mean clinical follow-up was 7 years (range, 2-13 years). Mean radiographic follow-up was 2.5 years (range, 0.5-9 years). Fourteen (70%) lesions were grade 3 and 6 (30%) were grade 4. Eleven knees had lateral condyle lesions and 9 had medial lesions. Bioabsorbable fixation was used in 13 knees, metal fixation was used in 5 knees, and 2 knees were fixed with a combination of methods. Osseous integration was evident in 15 (75%) of 20 knees at final follow-up. The 5 unhealed lesions were lateral condylar lesions. Mean Tegner activity scores improved from 3.3 preoperatively to 5.6 at final follow-up. Mean Lysholm and International Knee Documentation Committee scores were 86.8 and 88.7, respectively, at final follow-up. Further operative intervention was required in 11 knees, with 50% of patients undergoing removal of hardware and 15% requiring subsequent osteochondral allograft transplantation. The authors recommend bioabsorbable fixation for symptomatic stable lesions and metal compression screws with staged removal for unstable lesions.

External validation of the national healthcare safety network risk models for surgical site infections in total hip and knee replacements

BACKGROUND The National Healthcare Safety Network surgical site infections risk models for hip (HPRO) and knee (KPRO) replacement are intended for case-mix adjustment when reporting surgical site infection rates across institutions, but they are not validated in external data sets. OBJECTIVE To evaluate the validity of HPRO and KPRO risk models and improvement in risk prediction with inclusion of information on morbid obesity and diabetes mellitus. DESIGN Retrospective cohort study. PATIENTS A single-center cohort of 21,941 hip and knee replacement procedures performed between 2002 and 2009. METHODS Discriminative ability was assessed using the concordance statistic (C statistic). Calibration was assessed using the Hosmer-Lemeshow goodness-of-fit tests. RESULTS The discrimination of HPRO was good, with a C statistic of 0.695 for surgical site infections and 0.749 for prosthetic joint infections. The discrimination of KPRO was worse than that of HPRO, with a C statistic of 0.592 for surgical site infections and 0.675 for prosthetic joint infections. Adding morbid obesity and diabetes mellitus to the HPRO and KPRO risk models modestly improved discrimination. There was no significant evidence of miscalibration based on the Hosmer-Lemeshow tests, but calibration of HPRO models appeared to be better than that of the KPRO models. CONCLUSION HPRO performed better than the KPRO in predicting surgical site infections after hip and knee replacements. Both fared well in predicting prosthetic joint infections.

Giant Cell Tumor of the Metacarpal: Case Report

Background: Giant cell tumor (GCT) of bone is a benign, though locally aggressive tumor, classically described as an eccentric lytic lesion, often with cortical expansion and destruction. It typically involves the metaphysis or epiphysis of long bones in skeletally mature patients, with a slight female predominance. The incidence in the small bones of the hand has been reported to be 2% to 5%. Methods: Treatment options have evolved in recent years, and currently include intralesional curettage with or without adjuvant therapy, wide resection, and occasionally amputation. Results: In this report, we present a long-term follow-up (10 years) of a patient with GCT involving a metacarpal, who was initially reconstructed with a metacarpal head allograft, which was eventually revised to a metacarpophalangeal (MCP) total joint arthroplasty. Conclusions: To our knowledge, this is the only report of pyrocarbon being used for tumor reconstruction and the only report of late MCP allograft salvage.

Pediatric Pelvic Ring Injuries

The purpose of this study was to determine whether pelvic fracture pattern is associated with transfusion requirements or concomitant injuries in pediatric patients. This was a single-institution, retrospective review from 1970 to 2000. Pelvic ring injuries were classified using the Orthopaedic Trauma Association system. Injury Severity Scores were assigned. Ninety patients were included in this study. There were 27 A-type (30.0%), 51 B-type (56.7%), and 12 C-type (13.3%) injuries. Mean Injury Severity Scores were 8.1 for 61 A-type, 12.7 for 61 B-type, and 23.6 for 61 C-type fractures (P<.0001). Transfusion was required for 14.8% of A-type, 18.4% of B-type, and 66.7% of C-type injuries (P=.0009). There was no significant association with the number of units transfused (P=.9614). Decreased pelvic ring fracture stability was associated with an increased need for blood transfusion, although not with the number of units. Pelvic ring fracture stability may be a marker of associated injuries. [Orthopedics. 2018; 41(5):e701-e704.].

Adventitial Cysts of the Radial Artery are Joint Connected: Radial artery adventitial cysts

Volar radial wrist masses are common. Adventitial cysts of the radial artery are rarely reported and poorly understood. We describe a case series of adventitial cysts in association with the radial artery and detail their pathophysiology and treatment. We conducted an Institutional Review Board‐approved retrospective review of patients treated at our institution from 1997 to 2018. Twelve patients were identified. Presenting symptoms typically included pain and swelling over the volar radial wrist. High‐resolution magnetic resonance imaging (MRI) demonstrated tubular, cystic lesions within the adventitia of the radial artery with connections to the wrist joint confirmed on multiplanar imaging: (radiocarpal joint = 10; scaphotrapeziotrapezoidal joint = 1; and intercarpal joint = 1). Seven patients underwent operation, at which time the cyst was resected and the articular branch disconnected. These patients reported resolution of their symptoms without clinical recurrence. The consistent finding of a joint connection in these cases of adventitial cysts associated with the radial artery has important clinical implications. The joint connection needs to be disconnected. Level of evidence: Level IV, case series. Clin. Anat. 32:201–205, 2019.

Unusual Causes of Carpal Tunnel Syndrome

Most cases of carpal tunnel syndrome (CTS) are idiopathic, although several associated conditions have been previously described. Outlined here are some of the rare causes of carpal tunnel syndrome, including space-occupying lesions, inflammatory conditions, infection, trauma, and anatomic variants. These patients often present with a more complicated clinical picture. Diagnosis is delayed in many cases. The symptoms of carpal tunnel syndrome may be the first sign of a more serious underlying condition. Advanced imaging is often necessary. In many cases, adequate treatment involves more than decompression of the nerve.

The Utility of Routine Postoperative Radiographs after Pinning of Pediatric Supracondylar Humerus Fractures

Background: The purpose of this study was to determine the frequency with which postoperative radiographs resulted in a change in management following closed reduction and percutaneous pinning of displaced pediatric supracondylar humerus fractures. We hypothesize that only the initial postoperative radiograph will lead to changes in management of operative supracondylar humerus fractures. Methods: A retrospective review was performed at 2 level I pediatric trauma centers. Inclusion criteria were patients below 18 years of age who sustained supracondylar humerus fractures (Gartland type II, III, IV) who were operatively treated from 2008 to 2013 with adequate radiographic follow-up. Patients with flexion type, intra-articular, transphyseal, and open fractures were excluded from the study. Routine radiographs were taken at initial follow-up (1 wk postoperatively) and at pin removal (3 to 4 wk postoperatively). Results: The final analysis included 572 patients. Initial postoperative radiographs changed treatment in 9 patients (1.6%), including revision surgeries, 2 pin adjustments, and 2 early pin removals. At the time of pin removal, 20 (3.5%) patients required further immobilization. There were no changes to the initial plan for continued nonoperative treatment at final follow-up (6 to 8 wk postoperatively). Conclusions: In this large retrospective series of patients treated with closed reduction and percutaneous pinning of displaced supracondylar humerus fractures, radiographs at 3 weeks do not reveal a need to return to the operating room or other significant pathology. These findings suggest that radiographs should be obtained within 7 to 10 days postoperatively for type III fractures and may only need to be repeated if the clinical situation warrants it, such as severe fracture pattern, persistent pain, or clinical deformity. Level of Evidence: Level IV—case series.