Haber, Daniel B.

Purpose: This study aims to report the epidemiology of patellar sleeve injuries, describe diagnostic findings and treatment, and assess functional outcomes following different treatments. Methods: A medical database was queried from 1990 to 2016 to identify patients ≤18 years presenting to a single pediatric institution with a patellar sleeve injury. Patients with significant comorbidities or previously operatively treated for ipsilateral knee injuries were excluded. Standard demographic data, mechanism of injury, skeletal maturity, injury-related radiographic parameters, along with treatment paradigms, post-treatment clinical and radiographic findings, and patient-reported outcomes were collected. Results: A total of 90 patients, mean age of 10.7 years (range: 7–17) was included, of which 69 (77%) were male. Seventy-three percent of all injuries occurred while playing sports (particularly football/basketball/soccer), with “direct blow” or “landing” being the most prevalent mechanisms of injury. Twenty-six (29%) underwent operative treatment, with transosseous suture fixation being the most popular surgical technique (73%). Of the 64 (71%) non-operatively treated patients, 18 (39%) were placed in a hinged knee brace locked in extension with the remainder split between casting and standard knee immobilizer. Compared to the non-operative cohort, a higher percentage of the operative group had a pre-treatment extensor lag (p < 0.001) and greater fragment displacement (p < 0.001) with patella alta (p < 0.001) on imaging. There was no difference in outcome scores (Pedi-IKDC/Lysholm) or patella alta on radiographs between groups. Post-treatment surveys indicated no difference in residual pain or ability to return to sport. Conclusion: This large case series provides valuable epidemiologic, clinical, and radiographic data describing patellar sleeve fractures, along with outcomes following non-operative and operative treatments. Level of evidence: IV.

When fracture of an extensively porous-coated femoral component occurs, its removal at revision total hip arthroplasty (THA) may require a femoral osteotomy and the use of a trephine. The remaining cortical bone after using the trephine may develop thermally induced necrosis. A retrospective review identified 11 fractured, well-fixed, uncemented, extensively porous-coated femoral components requiring removal using a trephine with a minimum of two years of follow-up.The mean time to failure was 4.6 years (1.7 to 9.1, standard deviation (sd) 2.3). These were revised using a larger extensively porous coated component, fluted tapered modular component, a proximally coated modular component, or a proximal femoral replacement. The mean clinical follow-up after revision THA was 4.9 years (2 to 22, sd 3.1). The mean diameter of the femoral component increased from 12.7 mm (sd 1.9) to 16.2 mm (sd 3.4; p > 0.001). Two revision components had radiographic evidence of subsidence that remained radiographically stable at final follow-up. The most common post-operative complication was instability affecting six patients (54.5%) on at least one occasion.A total of four patients (36.4%) required further revision: three for instability and one for fracture of the revision component. There was no statistically significant difference in the mean Harris hip score before implant fracture (82.4; sd 18.3) and after trephine removal and revision THA (81.2; sd 14.8, p = 0.918).These findings suggest that removal of a fractured, well-fixed, uncemented, extensively porous-coated femoral component using a trephine does not compromise subsequent fixation at revision THA and the patient’s pre-operative level of function can be restored. However, the loss of proximal bone stock before revision may be associated with a high rate of dislocation post-operatively.Cite this article: Bone Joint J 2015;97-B:1192–6.