Michael J. Bronson

Prevalence of modifiable surgical site infection risk factors in hip and knee joint arthroplasty patients at an urban academic hospital.

Surgical site infections after hip and knee arthroplasty can be devastating if they lead to periprosthetic joint infection. We examined the prevalence of the modifiable risk factors for surgical site infection described by the American Academy of Orthopaedic Surgery Patient Safety Committee. Our study of 300 cases revealed that only 20% of all cases and 7% of revision cases for infection had no modifiable risk factors. The most common risk factors were obesity (46%), anemia (29%), malnutrition (26%), and diabetes (20%). Cases with obesity or diabetes were associated with all histories of remote orthopedic infection, 89% of urinary tract infections, and 72% of anemia cases. The high prevalence of several modifiable risk factors demonstrates that there are multiple opportunities for perioperative optimization of such comorbidities.

Triradiate cartilage injury. Report of two cases and review of the literature.

Acetabular fractures in children are not uncommon, but traumatic disruption of the acetabular triradiate cartilage occurs infrequently and may be associated with acetabular dysplasia and subluxation of the hip. The triradiate cartilage is at risk from birth to closure. The earlier the age at the time of injury, the greater the chance of acetabular dysplasia. In two cases of triradiate cartilage injury, one had premature closure of the triradiate cartilage with subsequent acetabular dysplasia requiring acetabular reconstruction. A review of the literature reveals ten other cases of acetabular dysplasia after injury to the triradiate cartilage. A review of all 11 cases reveals age to be the most significant factor in the development of acetabular dysplasia, with the greatest degree of growth disturbance occurring in young patients.

Prospective Study of Porous-Coated Anatomic Total Hip Arthroplasty

Seventy-five uncemented porous-coated total hip prostheses were implanted in 64 patients. The results were reviewed after a mean follow-up period of 47 months (range, 40-64 months). The mean preoperative rating was fair, and the mean postoperative rating was excellent. There were six dislocations. Ten patients had mild thigh pain at one year; by two years, the pain had resolved in six patients. Neither moderate nor severe limp nor significant loosening of beads was observed. Only one patient had progressive radiolucent lines. The high rate of dislocation may be related to a compromise of acetabular position to obtain bony fixation in acetabula early in the series. The clinical results were encouraging.

Novel technique for intraoperative sciatic nerve assessment in complex primary total hip arthroplasty: a pilot study

Introduction: Sciatic nerve injury (SNI) is a potentially devastating complication after total hip arthroplasty (THA). Intraoperative neural monitoring has been found in several studies to be useful in preventing SNI, but can be difficult to implement. In this study, we examine the results of using a handheld nerve stimulator for intraoperative sciatic nerve (SN) monitoring during complex THA requiring limb lengthening and/or significant manipulation of the SN. Methods: A consecutive series of 11 cases (9 patients, 11 hips) with either severe developmental dysplasia of the hip (Crowe 3-4) or other underlying conditions requiring complex hip reconstruction involving significant leg lengthening and/or nerve manipulation. SN function was monitored intraoperatively by obtaining pre- and post-reduction thresholds during component trialing. The results of nerve stimulation were then used to influence intraoperative decision-making. Results: No permanent postoperative SN complications occurred, with an average increase of 28.5 mm in limb length, range (6-51 mm). In 2 out of 11 cases, a change in nerve response was identified after trial reduction, which resulted in an alternate surgical plan (femoral shortening osteotomy and downsizing femoral head). In the remaining cases, the stimulator demonstrated a response consistent with the baseline assessment, assuring that the appropriate lengthening was achieved without SNI. 1 patient had a transient motor and sensory peroneal nerve palsy, which resolved within 2 weeks. Conclusions: The intraoperative use of a handheld nerve stimulator facilitates surgical decision-making and can potentially prevent SNI. The real-time assessment of nerve function allows immediate corrective action to be taken before nerve injury occurs.

CORR Insights®: Do various factors affect the frequency of manipulation under anesthesia after primary total knee arthroplasty?

T he gold standard for the surgical treatment of patients with advanced arthritis remains TKA. Its reliability in relieving pain and improving function in the shortand long-term is well proven. Despite our best efforts, however, joint replacement surgery is not without its complications. In particular, the development of arthrofibrosis can be substantially disabling to the 1% to 12% [2, 6, 9] of patients who develop it. The etiology is multifactorial, often unknown, and frequently resistant to treatment. There is a large quantity of literature on arthrofibrosis. Recent studies [11] have identified both patient-dependent and independent risk factors, which include limited ROM preoperatively, prior knee surgery, complex regional pain syndrome, lack of patient compliance with therapy, and diminished patient pain threshold. Other patientrelated factors associated with the development of arthrofibrosis include nonwhite race younger than 65 years of age, diabetes, hypercholesterolemia, and smoking [5]. Technical factors include ‘‘overstuffing’’ the knee (both tibiofemoral and patellofemoral compartments), component malalignment in all planes, instability, balance flexion-extension gap failure, joint line elevation, infection, and heterotopic ossification [10]. But even when these risk factors are absent, some patients can still develop the condition through an exaggerated fibroblastic response, tissue metaplasia, or revision interventions [4]. Numerous treatments options have been used, but their results are inconsistent. These options include manipulation under anesthesia with or without arthroscopic intervention, open arthrolysis, and revision surgery [3].