Migliore and Granata Furthermore preliminary data indicate a potential use for hyaluronans in the treatment of inﬂammatory arthropathies (eg, acute joint trauma and fractures) that require long periods of immobilization, and in tissue engineering for chondral defects. Although the trials that have investigated the use of hyaluronan therapy for the management of traumatic and degenerative musculoskeletal disorders seen in sports medicine have limitations in design and patient number, the results have been promising and suggest that larger controlled clinical trials are warranted (Peyron and Balasz 1974). HA products in the intra-articular treatment of hip OA Few data exists in literature about the viscosupplementation of hip OA in spite of it is the second most common site of the disease after the knee (Pelletier and Martel-Pelletier 1993; Pagnano and Westrich 2005). One of the limiting factors for this practice might be related to the injection procedure. The intra-articular injection of the hip is not as easy as for the knee, mainly for anatomical features of the joint and the proximity of “sensitive” structures such as the femoral artery and nerves. Even though hip injection may be performed “blindly”, failure rate is nevertheless signiﬁcant (Jones et al 1993) and when using a slow absorbing viscosupplement like hyaluronan, the potential local complications may jeopardize the therapeutic beneﬁt (Jackson et al 2002). For such reasons, it has been suggested to perform intra-articular injection of the hip under radiological or ultrasound control. Although several ultrasound guidance techniques were available (Qvistgaard et al 2001), we developed a personal one using an antero-superior approach (Migliore et al 2003). Since no single or double blind randomized controlled trials have yet been published, we analyzed all the available trials on MEDLINE to assess viscosupplementation for the treatment of hip OA (Table 3). The efﬁcacy data underlines signiﬁcant improvement in pain and function as has been shown in the knee OA stud- ies despite the small size of the sample. The short period of observation has not seen a change in the natural history of the disease. In order to conﬁrm these promising data, large scale double blind controlled studies must be carried out. Conclusions The ongoing studies continue to further our understanding of the fundamental mechanisms that likely underlie the thera- peutic beneﬁts of this treatment. The meta-analysis in prog- ress are further establishing a role for viscosupplementation in ameliorating the symptoms of knee and hip osteoarthritis. At the moment it is clear that viscosupplementation is more efﬁcacious in the initial and intermediate stages of OA more than at an advanced stages and that this therapy is exception- ally safe compared with other OA treatments. Despite recent progress, many unresolved issues require further study. These include determining the cost- effectiveness of viscosupplementation, exploring the thera- peutic effectiveness and safety, clearly deﬁning the relation between molecular weight and the clinical effectiveness of the various hyaluronan products, establishing optimal dosing regiments, evaluating efﬁcacy in different OA populations, determining how to best incorporate viscosupplementation into the evolving OA treatments algorithms, exploring the potential for treatment of OA joints other than the knee, as already shown for the hip, and assessing potential synergistic or additive effects with other modalities such NSAIDs and SYSADOA. It is encouraging that hyaluronan-based therapy is proving to be safe and effective for many patients with symptomatic hip and knee OA despite the fact that many unresolved issues requiring further study remain. If hyal- uronan derivatives are eventually proven to have clear Table 3 Vscosupplementation studies for the treatment of hip osteoarthritis Author year HA Nr of pts. Outcome measures Months of follow-up Nr.of injections Brigantini 1994 Hyalgan 44 P/GA/NSAIDs 6 3–5 Brocq 2002 Synvisc 22 LI 1–6 1–2 Conrozier 2003 Synvisc 57 P/W/GA 3–6 1–2 Vad 2003 Synvisc 22 P/AAOS/LLCSS 12 3 Migliore 2003 Hyalgan 28 P/LI/NSAIDs NG 1–3 Caglar-Yagci 2005 Synvisc 14 P/LI/15 mWT 3 3 Berg 2004 Durolane 31 W/GA 3 1 Migliore 2005 Synvisc 26 P/LI/NSAIDs 12 1–2 Tikiz 2005 Synvisc vs Ostenil 25 vs 18 P/W/LI 6 3 Migliore 2006 Synvisc 36 P/W/NSAIDs 18 1–2 Abbreviations: P, pain; GA, global assessment; 15 mWT, 15-meter walking time; NSAIDs, NSAIDs consumption; LI, Lequesne index; W,Womac index;AAOS,American Academy of Orthopaedic Surgeons; LLCSS, Lower Limb Core Scale Score. 368 Clinical Interventions in Aging 2008:3(2)