Endoscopic Pubic Symphysectomy for Athletic Osteitis Pubis.

Osteitis pubis is a common form of athletic pubalgia associated with femoroacetabular impingement. Endoscopic pubic symphysectomy was developed as a less invasive option than open surgical curettage for recalcitrant osteitis pubis. This technical note demonstrates the use of the anterior and suprapubic portals in the supine lithotomy position for endoscopic burr resection of pubic symphyseal fibrocartilage and hyaline endplates. Key steps include use of the suprapubic portal for burr resection of the posteroinferior symphysis and preservation of the posterior and arcuate ligaments. Endoscopic pubic symphysectomy is a minimally invasive bone-conserving surgery that retains stability and may be useful in the treatment of recalcitrant osteitis pubis or osteoarthritis. It nicely complements arthroscopic surgery for femoroacetabular impingement and may find broader application in this group of co-affected athletes.

Arthroscopic surgery for global versus focal pincer femoroacetabular impingement: are the outcomes different?

To determine outcomes from arthroscopic surgery for global pincer femoroacetabular impingement (FAI), a large multicenter prospective study investigating arthroscopic surgical outcomes was performed with minimum 2-year follow-up. Global (center-edge angle 40+ degrees) and Focal (center-edge angle 25-39 degrees) cohorts were based on pre-operative radiographs. Pre-operative and intra-operative findings, surgical procedures, post-operative nonarthritic hip score (NAHS) and satisfaction (5-point Likert scale), complications and conversion arthroplasties were compared. A nested case-control study was also performed. The Global cohort consisted of 15 patients (18 hips) of mean age 37.2 years. Pre-operative NAHS was 51.5 and 74.1 at 24+ months post-surgery. The change in NAHS was significant (P = 0.01). Mean satisfaction was 4.2. There was one total hip arthroplasty (THA) conversion (5.6%), no revision surgeries or complications. The Focal cohort consisted of 125 patients (129 hips) of mean age 39.8 years. Pre-operative NAHS was 54.8 and 77.8 at 24+ months post-surgery. The change in NAHS was significant (P < 0.0001). Mean satisfaction was 4.2. There were eight THA conversions (6.2%), three complications (2.3%) and two revision surgeries (1.5%). Cohort comparisons revealed no statistically significant difference in NAHS (P = 0.30), satisfaction (P = 0.92) or THA conversion rate (P = 0.91). The nested case-control study found mean post-operative change in NAHS was +22.2 and +20.4, respectively, at 24+ months (P = 0.76). Arthroscopic treatment of global pincer FAI is a safe and effective procedure. With outcomes comparable to those observed in the arthroscopic treatment of lesser focal deformities, arthroscopic surgery provides a less invasive option for the treatment of global pincer FAI.

The critical corner of cam femoroacetabular impingement: clinical support of an emerging concept.

PURPOSE: The purpose of this study was to evaluate the concept of cam femoroacetabular impingement (FAI) occurring medial to the classic anterolateral (AL) quadrant. METHODS: Forty-four patients met the inclusion criteria of cam FAI and underwent arthroscopic AL femoroplasty. Goniometric measurements of intraoperative hip internal rotation (HIR) in 90° of hip flexion and 0° of adduction were obtained. Thirty patients (14 male and 16 female), comprising the substance of this study, exhibited HIR of less than 40° after AL femoroplasty and underwent further anteromedial (AM) femoroplasty with subsequent repeat measurement of HIR. Nonparametric statistical analysis was performed. RESULTS: Preoperative HIR averaged 20.8° (range, 10° to 29°); intraoperative HIR averaged 29.5° (range, 18° to 39°) after AL femoroplasty and 42.7° (range, 32° to 61°) after additional AM femoroplasty. The gain in HIR after AL femoroplasty was 8.7° (range, 2° to 23°) (P < .0001). The further gain in HIR after AM femoroplasty was 13.2° (range, 2° to 22°) (P < .0001). The overall gain in HIR after AL and AM femoroplasty was 21.9° (range, 13° to 38°) (P < .0001). A consistent landmark termed the resident's ridge of the hip accompanied all cases of AM cam impingement. CONCLUSIONS: Femoroplasty of the AM "critical corner" may improve cam decompression and supports the concept of cam impingement extending beyond the classic AL quadrant of the proximal femur. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Factors associated with prolonged wound drainage after primary total hip and knee arthroplasty.

BACKGROUND: Prolonged wound drainage following total hip or total knee arthroplasty has been associated with an increased risk of postoperative morbidity. The purpose of this study was to determine the pharmacologic, surgical, and patient-specific factors that are associated with prolonged wound drainage and the relationship of this complication to the length of hospital stay and the rate of wound infections. METHODS: We conducted a retrospective observational study of 1211 primary total hip arthroplasties and 1226 primary total knee arthroplasties. Prospectively collected data included body mass index, intraoperative blood loss, surgical time, type of prophylaxis against deep venous thrombosis, and length of hospital stay. The association of these factors with the duration of postoperative wound drainage was analyzed. An acute infection developed after fifteen primary total hip arthroplasties and ten primary total knee arthroplasties. The patients with an acute postoperative infection were compared with their uninfected counterparts, and an odds ratio was determined to estimate the risk of prolonged wound drainage resulting in a wound infection. RESULTS: Morbid obesity was strongly associated with prolonged wound drainage in the total hip arthroplasty group (p = 0.001) but not in the total knee arthroplasty group (p = 0.590). An increased volume of drain output was an independent risk factor for prolonged wound drainage in both groups. Patients who received low-molecular-weight heparin for prophylaxis against deep venous thrombosis had a longer time until the postoperative wound was dry than did those treated with aspirin and mechanical foot compression or those who received Coumadin (warfarin); this difference was significant on the fifth postoperative day (p = 0.003) but not by the eighth postoperative day. Prolonged wound drainage resulted in a significantly longer hospital stay in both groups (p < 0.001). Each day of prolonged wound drainage increased the risk of wound infection by 42% following a total hip arthroplasty and by 29% following a total knee arthroplasty. CONCLUSIONS: Morbid obesity, the use of low-molecular-weight heparin, and a higher drain output were associated with a prolonged time until the postoperative wound was dry following a primary total hip arthroplasty, whereas a higher drain output was the only risk factor associated with prolonged drainage following a primary total knee arthroplasty. Prolonged drainage was associated with a higher rate of infection following a primary total hip arthroplasty, whereas obesity was the only identified independent risk factor for postoperative infection following a primary total knee arthroplasty.

ADAMTS-12 associates with and degrades cartilage oligomeric matrix protein.

Loss of articular cartilage because of extracellular matrix breakdown is the hallmark of arthritis. Degradative fragments of cartilage oligomeric matrix protein (COMP), a prominent noncollagenous matrix component in articular cartilage, have been observed in the cartilage, synovial fluid, and serum of arthritis patients. The molecular mechanism of COMP degradation and the enzyme(s) responsible for it, however, remain largely unknown. ADAMTS-12 (a disintegrin and metalloprotease with thrombospondin motifs) was shown to associate with COMP both in vitro and in vivo. ADAMTS-12 selectively binds to only the epidermal growth factor-like repeat domain of COMP of the four functional domains tested. The four C-terminal TSP-1-like repeats of ADAMTS-12 are shown to be necessary and sufficient for its interaction with COMP. Recombinant ADAMTS-12 is capable of digesting COMP in vitro. The COMP-degrading activity of ADAMTS-12 requires the presence of Zn2+ and appropriate pH (7.5-9.5), and the level of ADAMTS-12 in the cartilage and synovium of patients with both osteoarthritis and rheumatoid arthritis is significantly higher than in normal cartilage and synovium. Together, these findings indicate that ADAMTS-12 is a new COMP-interacting and -degrading enzyme and thus may play an important role in the COMP degradation in the initiation and progression of arthritis.

ADAMTS-7: a metalloproteinase that directly binds to and degrades cartilage oligomeric matrix protein.

Degradative fragments of cartilage oligomeric matrix protein (COMP) have been observed in arthritic patients. The physiological enzyme(s) that degrade COMP, however, remain unknown. We performed a yeast two-hybrid screen (Y2H) to search for proteins that associate with COMP to identify an interaction partner that might degrade it. One screen using the epidermal growth factor (EGF) domain of COMP as bait led to the discovery of ADAMTS-7. Rat ADAMTS-7 is composed of 1595 amino acids, and this protein exhibits higher expression in the musculoskeletal tissues. COMP binds directly to ADAMTS-7 in vitro and in native articular cartilage. ADAMTS-7 selectively interacts with the EGF repeat domain but not with the other three functional domains of COMP, whereas the four C-terminal TSP motifs of ADAMTS-7 are required and sufficient for association with COMP. The recombinant catalytic domain and intact ADAMTS-7 are capable of digesting COMP in vitro. The enzymatic activity of ADAMTS-7 requires the presence of Zn2+ and appropriate pH (7.5-9.5), and the concentration of ADAMTS-7 in cartilage and synovium of patients with rheumatoid arthritis is significantly increased as compared to normal cartilage and synovium. ADAMTS-7 is the first metalloproteinase found to bind directly to and degrade COMP.

An extracellular site on tetraspanin CD151 determines alpha 3 and alpha 6 integrin-dependent cellular morphology.

The alpha 3 beta 1 integrin shows strong, stoichiometric, direct lateral association with the tetraspanin CD151. As shown here, an extracellular CD151 site (QRD(194-196)) is required for strong (i.e., Triton X-100-resistant) alpha 3 beta 1 association and for maintenance of a key CD151 epitope (defined by monoclonal antibody TS151r) that is blocked upon alpha 3 integrin association. Strong CD151 association with integrin alpha 6 beta 1 also required the QRD(194-196) site and masked the TS151r epitope. For both alpha 3 and alpha 6 integrins, strong QRD/TS151r-dependent CD151 association occurred early in biosynthesis and involved alpha subunit precursor forms. In contrast, weaker associations of CD151 with itself, integrins, or other tetraspanins (Triton X-100-sensitive but Brij 96-resistant) were independent of the QRD/TS151r site, occurred late in biosynthesis, and involved mature integrin subunits. Presence of the CD151-QRD(194-196)-->INF mutant disrupted alpha 3 and alpha 6 integrin-dependent formation of a network of cellular cables by Cos7 or NIH3T3 cells on basement membrane Matrigel and markedly altered cell spreading. These results provide definitive evidence that strong lateral CD151-integrin association is functionally important, identify CD151 as a key player during alpha 3 and alpha 6 integrin-dependent matrix remodeling and cell spreading, and support a model of CD151 as a transmembrane linker between extracellular integrin domains and intracellular cytoskeleton/signaling molecules.