Dahm, Diane L.

A 16‐year‐old high school football player presented with 4 months of anterior knee pain and small, mobile, prepatellar “lumps” after falling onto an opponent's cleat. He reported knee pain primarily during knee flexion and direct pressure during squatting and kneeling. Knee radiographs were unremarkable. Ultrasonography revealed multiple, freely mobile, subcutaneous nodules of variable size and echogenicity in the prepatellar region. Analysis of magnetic resonance imaging suggested possible fat necrosis but was nondiagnostic. The patient opted for surgical exploration, at which time multiple, opalescent subcutaneous nodules were removed. Pathology was consistent with encapsulated fat necrosis. After surgery, his symptoms resolved, and he returned to sports without restrictions.

Objectives: Arthroscopic knee procedures are commonly performed in pediatric/adolescent patients. Reported complications following these procedures are low, however, no childhood specific data exists. Therefore, the purpose of this study is to determine the acute complications (within 6 months) of arthroscopic knee procedures in patients aged 17 years or less. Methods: This is a retrospective review of patients aged 17 years or less who underwent an arthroscopic knee procedure from 1997 to 2009 at a single institution. Demographic and surgical data was collected, in addition to specific data on intra-operative and post-operative complications. Minor complications included peripheral nerve block failure, regional anesthesia failure requiring conversion to general anesthesia, superficial wound infection/dehiscence, persistent knee effusion requiring aspiration, and sensory nerve dysesthesia. Major complications included death, major medical complication, septic arthritis, wound requiring repeat closure, arthrofibrosis, equipment failure, and revision surgery. Results: 1015 patients (555 males (54.7%), 460 females (45.3%)) with average age 15.3 (range 4-17) years were analyzed. The average operative time was 133.9 minutes (range 14-520). 467 (46%) underwent ACL reconstruction, 465 (45.8%) underwent synovectomy, treatment of an OCD lesion, meniscal treatment, or lateral release, 52 (5%) had a medial patellofemoral ligament reconstruction +/- tibial tubercle transfer, 17 (1.7%) arthroscopic fixation of a tibial eminence fracture, and 14 (1.4%) other ligament reconstruction. There were 147 (14.5%) total complications recorded. Major complications occurred in 21 (1.4%) of patients and minor complications in 126 (12.4%) of patients. Major complications included: intra-articular instrument breakage in 1(0.098%), septic arthritis in 4 patients (0.394%), 9 wounds requiring repeat closure (0.886%), arthrofibrosis in 5 patients (0.492%), unplanned subsequent surgical procedure in 3 patients (0.002%), and death in 1 patient (0.098%). 2 patients were readmitted to the hospital (1 DIC, 1 a-fib and syncope). There were no pulmonary emboli or DVTs, and no vascular injuries. No patients developed CRPS. Minor complications included:5 patients (0.492%) sensory nerve paresthesias, 10 (0.985%) patients with failed regional anesthetic, 16 (1.57%) patients with post-operative pain pump that required early discontinuation, 18(1.77%) patients with superficial wound infection/irritation, 60 (5.91%) patients with persistent effusion/hemarthrosis requiring arthrocentesis, and 17(1.67%) patients had medical problems that required intervention (asthma exacerbation, urinary retention). Conclusion: Major complications following knee arthroscopy in children and adolescents are relatively low 1.4%. Minor complications are more common (12.4%) but did not alter the post-operative course or recovery. DVT, PE, and CRPS did not occur in this patient cohort.

Objectives: TT-TG distance is a commonly used measurement for surgical decision-making in patients with patellofemoral malalignment and instability. This measurement has historically been performed utilizing axial CT scans. More recently, MRI has been proposed as an equivalent test for measurement of TT-TG distance. We sought to determine the reliability of TT-TG measurements on both MRI and CT, and to determine whether the measurements can be used interchangeably. Methods: All patients diagnosed with patellar instability who had received both CT and MRI of the knee between 2003 and 2011 were included (n=59 knees in 54 patients). Two fellowship trained musculoskeletal radiologists measured the TT-TG distances for each patient by CT and MRI in a randomized, blinded fashion for a total of 236 measurements. Inter-observer reliability was calculated between radiologists for both imaging modalities and inter-methods reliability was calculated between the two imagining modalities. The results are reported using intraclass correlation coefficients (ICC) and Bland Altman analysis (BAA). Results: The 59 knees had a mean TT-TG distance of 16.9 mm (range: 8.3-25.8) by CT and 14.7 mm (range: 1.5-25.1) by MRI. Eighteen patients (31%) had a TT-TG ≥ 20 mm by CT, and only 9 (15%) had a TT-TG ≥ 20 mm by MRI. Inter-observer reliability between the radiologists was considered excellent for both CT and MRI (ICC = 0.777 and 0.843 respectively). When comparing CT to MRI, however, the ICC was considered only fair for each of the two raters (0.532 and 0.539). A total of 11 patients (19%) had a TT-TG ≥ 20 mm on CT preoperatively and underwent distal realignment by tibial tubercle osteotomy (TTO). In this surgical subgroup, the mean TT-TG on CT was 22.5 mm (range 19.8-25.8) while the mean TT-TG on MRI was only 18.7 mm (range 14.4-22.8). Conclusion: TT-TG distance can be measured with excellent inter-rater reliability on both MRI and CT scans; however, the values derived from these two tests may not be interchangeable. This observation should be taken into consideration when MRI is used for surgical planning since MRI may underestimate TT-TG distance when compared to CT.

Background: Tibial tubercle–trochlear groove distance (TT-TG) is a commonly used measurement for surgical decision making in patients with patellofemoral malalignment and instability. This measurement has historically been performed utilizing axial computed tomography (CT). More recently, magnetic resonance imaging (MRI) has been proposed as an equivalent method, but this has not yet been fully validated. Purpose: To determine the reliability of TT-TG distance measurements on both MRI and CT and to determine whether the measurements are interchangeable with one another. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: All patients with patellar instability who underwent both CT and MRI of the knee from 2003 to 2011 were included (n = 59 knees in 54 patients). Two fellowship-trained musculoskeletal radiologists measured the TT-TG distances for each patient by CT and MRI in a randomized, blinded fashion. Interobserver reliability was calculated between radiologists for both imaging modalities, and intermethod reliability was calculated between the 2 imaging modalities. The results are reported using intraclass correlation coefficients (ICCs) and Bland-Altman analysis. Results: The 59 knees had a mean TT-TG distance of 16.9 mm (range, 8.3-25.8 mm) by CT and 14.7 mm (range, 1.5-25.1 mm) by MRI. Interobserver reliability between the radiologists was considered excellent for both CT and MRI (ICC = 0.777 and 0.843, respectively). When comparing CT to MRI, the ICC was considered only fair for each of the raters (0.532 and 0.539). Eleven patients (19%) had a TT-TG distance of ≥20 mm on CT preoperatively and underwent distal realignment by tibial tubercle osteotomy. In this surgical subgroup, the mean TT-TG distance was 22.5 mm (range, 19.8-25.8 mm) by CT and only 18.7 mm (range, 14.4-22.8 mm) by MRI for a mean difference of 3.80 mm ( P < .001). Conclusion: The TT-TG distance can be measured with excellent interrater reliability on both MRI and CT; however, the values derived from these 2 tests may not be interchangeable. This observation should be taken into consideration when MRI is used for surgical planning because MRI may underestimate the TT-TG distance when compared with CT.

Abstract We present our technique for diagnosis and arthroscopic repair of a floating posterior‐inferior glenohumeral ligament avulsion injury. A high degree of suspicion based on the patient's history, along with careful examination, should alert the surgeon to the existence of this lesion. By use of an anterolateral viewing portal and precisely placed posterior working portals, the lesion is repaired through suture anchor fixation to the humeral head and glenoid rim in a carefully sequenced fashion to achieve appropriate tension and restore the anatomy. Technique Video video See video under supplementary data.

Background: As anterior cruciate ligament (ACL) reconstruction is performed increasingly in the United States, the rate of revision ACL reconstruction continues to rise. A paucity of literature exists with respect to repeat ACL revision surgery. Purpose: To evaluate the functional outcomes of patients who had undergone at least 2 revision ACL reconstructions. Study Design: Case series; Level of evidence, 4. Methods: The records of all patients who had undergone repeat revision ACL reconstructions between 1998 and 2009 were retrospectively reviewed. Data collected included patient demographics, operative findings, pre- and postoperative physical examination findings, radiographs, and Tegner, Lysholm, and International Knee Documentation Committee (IKDC) subjective scores. Results: Fifteen patients had undergone repeat revision ACL reconstruction during the study period. Mean age was 27 years (range, 18-57 years). Mean follow-up was 5 years (range, 2-10 years). At the time of repeat revision surgery, new tunnels were drilled in 9 of 15 (60%) cases. Of those, 8 of 9 (89%) were drilled because femoral tunnels were deemed “too anterior.” During repeat revision, 11 of 15 (73%) patients were noted to have a meniscal tear, and 9 of 15 (67%) had International Cartilage Repair Society (ICRS) grade 3 or 4 chondral lesions. Mean Lysholm score was 60 preoperatively and increased to 82 postoperatively ( P < .001). Mean preoperative IKDC score was 59, which increased to 80 postoperatively ( P < .001). Mean preoperative Tegner score was 6.0. Mean postoperative Tegner score was 4.5, with only 4 of 15 (27%) patients having returned to their prior activity level ( P < .001). Two patients (13%) sustained a traumatic rerupture. Presence of grade 3 or 4 chondral lesions and body mass index greater than 28 at the time of repeat revision were associated with a “fair” or “poor” outcome by Lysholm score ( P = .007 and P = .03, respectively) and IDKC subjective scoring ( P = .04 and P = .007, respectively). Conclusion: Repeat revision ACL reconstruction may improve the functional outcomes of patients who have failed revision ACL reconstruction. Most patients do not return to prior activity level following repeat revision. Presence of grade 3 or 4 chondral lesions and body mass index greater than 28 were associated with worse outcomes.

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.

AbstractPurposePatellofemoral arthroplasty remains controversial, primarily due to the high failure rates reported with early implants. Numerous case series have been published over the years detailing results of various first‐ and second‐generation implants. The purpose of this work is to summarize results published to date and identify common themes regarding implants, surgical techniques, and indications in order to maximize results of future procedures.MethodsA comprehensive review of the MEDLINE database was carried out to identify all clinical studies related to patellofemoral arthroplasty.ResultsFirst‐generation resurfacing implants were associated with relatively high failure rates in the medium term. Second‐generation implants, with femoral cuts based on TKA designs have yielded more promising medium‐term results. Surgical indications are specific and must be carefully followed to minimize poor results. Short‐term complications are generally related to patellar maltracking, while long‐term complications are generally related to progression of osteoarthritis in the tibiofemoral joint. Implant loosening and polyethylene wear are rarely reported. Short‐term results are favourable for new technology including custom implants and computer navigated surgery.ConclusionsOverall, recent improvements in implant design and surgical techniques have resulted in improvements in short‐ and medium‐term results. More work is required to assess the long‐term outcomes of modern implant designs.Level of evidenceIV.

The incidence of ACL tears is rising in the pediatric and adolescent populations as these individuals succumb to traumatic and nontraumatic athletic injuries. Management of this condition in the skeletally immature patient poses a challenge and is controversial. Operative reconstruction carries the concern for damage to the physis with resultant limb length inequality and angular joint deformity but provides stability to the knee and allows return of function in most patients. On the other hand, nonoperative treatment has been shown to carry an increased risk of meniscal and articular cartilage damage and is difficult from a compliance standpoint in this demographic. For the majority of skeletally immature patients, operative treatment is recommended as it has shown good clinical and functional results with minimal risk of growth disturbance. This paper aims to address the natural course of ACL injuries in the skeletally immature patient, treatment options with associated complications, and current preventative strategies.