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LARS™ – Managing lateral hip pain

In 1923 Stegemann et al.1 first described ‘juxta-trochanteric pain’ and attributed this to the condition of trochanteric bursitis. Bursitis implies that the condition must involve an inflammatory component, but more recently it has become apparent that a number of different pathologies could account for lateral sided hip pain. Trochanteric bursitis is still used to describe pain around the greater trochanteric region of the hip despite the absence of key signs of inflammation. Currently the most common term used to describe this condition in the literature is Greater Trochanteric Pain Syndrome (GTPS).


Images from animation and live surgery video show LARS™ sutured to the gluteal tendons and drawing the tendons down to the footprint on the GT

What is GTPS attributable to?

GTPS is often misdiagnosed or neglected due to a lack of clear understanding of the pathology involved and uncertainty surrounding how to treat patients. Patients are commonly prescribed conservative treatment options including anti-inflammatory medication and physiotherapy. Fearon et al.2 found that people with GTPS had low levels of full time work participation with pain and dysfunction levels indistinguishable from patients with severe osteoarthritis (OA) of the hip, awaiting total hip arthroplasty. Recent improvements in the understanding of the pathology of GTPS have revealed that tears of the gluteus medius or minimus muscles or their tendinous insertions, similar to rotator cuff tears seen in the shoulder3, are the most common cause of GTPS4,5,6.

Patients usually present with chronic lateral hip pain specifically located around the greater trochanteric region and weakness of the hip abductors, or tears can be identified during, or subsequent to, hip replacement surgery. X-ray can be used to exclude hip joint involvement (OA) and MRI scans have shown to be an accurate means of diagnosing abductor tendon tears7.

Do current treatment modalities work?


Current conservative treatment options, involving activity modifications, non-steroidal anti-inflammatory medications, physiotherapy and corticosteroid injections, tend to show high symptom recurrence rates at one year8. When conservative treatment fails, the next logical step is surgical investigation and repair of any tendon tears. Whilst Walsh et al.9 reported approximately 90% good results with suture repair alone, patients were required to remain non-weight bearing for six weeks. Extended periods of non-weight bearing can lead to additional postoperative complications with 8.3% of patients presenting with DVT in this study. Other studies using suture and anchor based surgical repairs have demonstrated good initial pain relief but high re-rupture rates of up to 31% at 12 months8 suggesting a more robust repair is required.

How is LARS™ different in gluteal repairs?


Rotator cuff repairs are routinely protected in an abduction sling, but this is impractical in gluteal tendon repairs. Early mobilisation may be a contributing factor to the high re-rupture rates seen with traditional suture
based repairs. The use of LARS to augment the repair aims to decrease the stress of the repair in the ambulating patient by spreading the load over a larger surface area of the soft tissues, providing an improved mechanical environment to facilitate healing rates. The LARS ligament is sutured to the deep surface of the gluteal tendons, pulled through a bone tunnel in the greater trochanter drawing the tendons back on to the decorticated footprint. The LARS   is secured in the bone tunnel using an interference screw and the repair is completed using trans-osseous suturing of the lateral portion of the tendons to the trochanteric bone. Over 1200 gluteal tendon repairs reinforced with LARS have been performed in Australia with very high patient satisfaction and low failure rates10, without the need for patients to remain non-weight bearing post-surgery. Reinforcing the gluteal tendon repair with LARS allows patients to be weight bearing as tolerated from 24 hours after surgery. LARS is a third generation synthetic, incorporating a high strength, novel design technology which minimises postoperative strength loss and material degradation11,12,13. As an augment, LARS provides immediate strength and stability to the repair, with increased resistance to elongation and low re-rupture rates, thereby facilitating rapid return to function and pain elimination post-surgery10,14,15.

References

1. Stegemann H. Arch Klin Chir. 1923.
2. Fearon A, et al. J Arthroplasty 2014.
3. Bunker TD et al. JBJS [Br]. 1997.
4. Williams BS et al. Anaesthesia and Analgesia. 2009.
5. Bird PA et al. Arthritis and Rheumatology. 2001.
6. Kingzett-Taylor A, et al. AJR. 1999.
7. Cvitanic O et al. AJR. 2004.
8. Davies H et al. Hip Int. 2009.
9. Walsh M et al. J Arthroplasty. 2011.
10. Bucher TA et al. Hip Int. 2014
11. LARS™ laboratory testing. Data held on file, Corin Group PLC 2005.
12. Ardern CL et al. Arthroscopy. 2010.
13. Mascarenhas R et al. MJM. 2008
14. Bajwa AS et al. Hip Int. 2011
15. Holroyd B et al. European Musculoskeletal Review. 2009