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Editorial Commentary: “Loose Lips Sink Ships”–But What About “Loose Hips”?

      Abstract

      Hip instability continues to be a challenge in hip preservation. Our understanding of the role of osseous anatomy, labral integrity and soft-tissue stabilizers has increased dramatically over the past several decades. Connective-tissue disorders such as Ehlers-Danlos syndrome pose a significant challenge to the management of instability in all joints but particularly in the hip. Ligamentum teres tears have been found to be more common than previously thought, although their significance is still not well understood. In patients with both Ehlers-Danlos syndrome and ligamentum teres tears, reconstruction and capsular plication result in moderate success, but not in all cases.
      Loose Lips Sink Ships. This popular American idiom is attributed to a United States government slogan created by the War Advertising Council during World War II.
      It was part of a poster propaganda campaign embarked upon by the United States Office of War Information to motivate and inspire US citizens in the war movement. In this case, the slogan was meant to advise military personnel and nonmilitary citizens to curtail the spread of rumors that might undermine the war strategy and the planned military maneuvers for fear of dire consequences. Although there is no such slogan in hip arthroscopy, “loose hips” have increasingly been recognized a way to “sink” a good result after hip-preservation surgery.
      As a fellow under the guidance of Dr. Marc Philippon in 2005–2006, I was amazed at the boundaries that were being pushed in evolving techniques for arthroscopic hip preservation. In particular, I recall that one of my co-fellows assisted in a ligamentum teres (LT) reconstruction. During our fellowship year, we were trying to become proficient in what is today considered a basic procedure of femoroplasty, acetabuloplasty and labral repair, while Dr. Philippon was pushing a novel reconstruction of a ligament that was historically considered a vestigial structure. My, how the times have changed!
      Hip arthroscopy has proven to be a successful procedure for the majority of patients.
      • Levy D.M.
      • Kuhns B.D.
      • Chahal J.
      • et al.
      Hip arthroscopy outcomes with respect to patient acceptable symptomatic state and minimal clinically important difference.
      As surgical techniques have evolved to allow us to perform less invasive hip preservation over the past 2 decades, our basic understanding of the complexity of the hip joint has continued to expand, and we have been forced to ask questions regarding patient selection and techniques. Initially, we debrided the labrum, then repaired it, and now reconstruction and augmentation for an irreparable or hypoplastic labrum are relatively common. Hip arthroscopists have come to recognize the complex interplay of both bony anatomic variations of femoroacetabular impingement (FAI) and dysplasia, as well as pathology involving static and dynamic soft-tissue stabilizers. After many years of performing arthroscopic hip surgery and observing the data supporting our techniques, it is still perplexing when patients do not achieve the desired improvement even though there is no obvious complication or failure. Hip instability may be the “torpedo” of optimal outcomes, sinking what would otherwise be successful procedures.
      Microinstability of the hip, as defined by Shu and Safran, is “extraphysiologic hip motion that causes pain with or without symptoms of hip joint unsteadiness”
      • Shu B.
      • Safran M.R.
      Hip Instability: Anatomic and clinical considerations of traumatic and atraumatic instability.
      ; it has been increasingly recognized as a symptom generator and cause of failure in hip arthroscopy. Several etiologies for microinstability have been defined. Insufficient bone in the form of borderline dysplasia or overcorrection of pincer or cam deformities may lead to abnormal motion and subsequent chondral damage. However, even in the setting of normal bony anatomy, soft tissues have been found to play an important role in the stability of the hip.
      • Safran M.R.
      Microinstability of the hip: Gaining acceptance.
      The role of the labrum in creating a suction seal of the femoral head in the acetabulum has been well demonstrated in biomechanical studies, leading to a strategy of repair, augmentation and reconstruction.
      • Ferguson S.
      • Bryant J.
      • Ganz R.
      • et al.
      An in vitro investigation of the acetabular labral seal in hip joint mechanics.
      ,
      • Signorelli C.
      • Bonanzinga T.
      • Lopomo N.
      • et al.
      Evaluation of the sealing function of the acetabular labrum: An in vitro biomechanical study.
      The integrity of the iliofemoral, ischiofemoral and pubofemoral ligaments has been well defined but has also been recognized as a potential issue for patients with connective tissue diseases like Ehlers-Danlos syndrome (EDS).
      • Larson C.M.
      • Stone R.M.
      • Grossi E.F.
      • et al.
      Ehlers-Danlos syndrome: Arthroscopic management for extreme soft-tissue hip instability.
      This past decade has seen a healthy debate regarding the importance of hip-capsule management with regard to residual postoperative microinstability. At this point, the pendulum has swung favorably to the side of capsular preservation and closure of T- and interportal capsulotomies.
      • Ortiz-Declet V.
      • Mu B.
      • Chen A.W.
      • et al.
      Should the capsule be repaired or plicated after hip arthroscopy for labral tears associated with femoroacetabular impingement or instability? A systemic review.
      The most recent culprit of hip instability to enter this discussion is the LT.
      • Rosinsky P.J.
      • Shapira J.
      • Lall A.C.
      • Domb B.G.
      All about the ligamentum teres: From biomechanical role to surgical reconstruction.
      As the number of hip arthroscopies increases worldwide, LT pathology has become widely recognized. The reported incidence of LT pathology has been as high as 51%.
      • O’Donnell J.M.
      • Devitt B.M.
      • Arora M.
      The role of the ligamentum teres in the adult hip: redundant or relevant? A review.
      The function of the LT has been increasingly examined and includes roles of stability, proprioception and synovial fluid distribution, all with the goal of chondral protection. The LT has been recognized a primary and secondary pain generator. Histologic studies have suggested that there are free nerve endings within the ligament that are likely stimulated in the setting of partial tears and synovitis. Instability resulting from LT injury has also been proposed as a pain generator. The LT serves as a restraint to hip flexion, adduction and external rotation.
      • Safran M.R.
      Microinstability of the hip: Gaining acceptance.
      Open hip surgery for FAI requires the transection of the LT, and as much as 25% of patients undergoing this procedure have reported long-term postoperative complaints of instability, suggesting that the LT dysfunction may result in persistent symptoms.
      • Phillips A.R.
      • Bartlett G.
      • Norton M.
      • et al.
      Hip stability after ligamentum teres resection during surgical dislocation for cam impingement.
      Historically, LT tears were treated by simple debridement, with mixed results. Recent literature has suggested that LT tears may portend an inferior outcome. This past March, Maldonado et al.
      • Maldonado D.R.
      • Chen S.L.
      • Walker-Santiago R.
      • et al.
      An intact ligamentum teres predicts a superior prognosis in patients with borderline dysplasia: A matched-pair controlled study with minimum 5-year outcomes after hip arthroscopic surgery.
      reported on 5-year outcomes of a matched-pair study comparing patients with and without LT tears in association with borderline dysplasia. Although the patient reported outcomes were generally favorable for both groups, the group undergoing LT debridement for tears had inferior patient acceptable symptomatic states for the modified Harris Hip Score (75% vs 100% of the control group).
      • Maldonado D.R.
      • Chen S.L.
      • Walker-Santiago R.
      • et al.
      An intact ligamentum teres predicts a superior prognosis in patients with borderline dysplasia: A matched-pair controlled study with minimum 5-year outcomes after hip arthroscopic surgery.
      Limited reports of LT reconstruction have offered a new treatment option that has had generally favorable outcomes.
      • Philippon M.J.
      • Pennock A.
      • Gaskill T.R.
      Arthroscopic reconstruction of the ligamentum teres: Technique and early outcomes.
      ,
      • O’Donnell J.
      • Klaber I.
      • Takla A.
      Ligamentum teres reconstruction: Indications, technique and minimum 1-year results in nine patients.
      Hip arthroscopy in patients with EDS has also been reported. In 2015, Larson et al.
      • Larson C.M.
      • Stone R.M.
      • Grossi E.F.
      • et al.
      Ehlers-Danlos syndrome: Arthroscopic management for extreme soft-tissue hip instability.
      reported on the outcomes of 16 patients with EDS undergoing arthroscopic correction of FAI and labral tears. They performed only an interportal capsulotomy and subsequent capsular plication after intra-articular pathology had been addressed. Significant improvements were reported in the modified Harris Hip Score, the 12-Item Short Form Survey and the Visual Analogue Scale at short-term follow-up.
      • Larson C.M.
      • Stone R.M.
      • Grossi E.F.
      • et al.
      Ehlers-Danlos syndrome: Arthroscopic management for extreme soft-tissue hip instability.
      Interestingly, none of these patients underwent LT reconstructions.
      In their article titled “Arthroscopic Ligamentum Teres Reconstruction: Minimum 2-Year Patient Reported Outcomes with Subanalysis of Patients with Ehlers-Danlos Syndrome,”
      • Rosinsky P.J.
      • Annin S.
      • Maldonado D.R.
      • et al.
      Arthroscopic ligamentum teres reconstruction: Minimum 2-year patient reported outcomes with subanalysis of patients with Ehlers-Danlos syndrome.
      authors Rosinsky, Annin, Maldonado, Kyin, Meghpara, Shapira, Lall, and Domb tackle both LT tears and EDS head-on. The authors should be commended for presenting the largest case series of arthroscopically assisted LT reconstructions at a minimum 2-year follow-up, including a subset of patients with EDS. Although there is much to glean from reading this study, which addresses such gross instability of the hip, many more questions emerge.
      The indications for LT reconstruction in this study included symptomatic hip instability as defined by objective physical examination in combination with failed nonoperative management. In all patients, intra-articular pathology was addressed, including labral pathology and FAI, in addition to performing LT reconstruction and capsular plication. The authors reported 2 failures of 11 and demonstrated improvement of objective examination findings of hip instability in the majority of patients, based on the Apprehension Test. Postoperative magnetic resonance imaging demonstrated only 1 case of graft resorption. The patients with EDS had higher failure rates; 3 of the 7 hips had unsuccessful outcomes, with 2 converting to total hip arthroplasties. Notably, this cohort is a difficult population, and though most patients reported clinically significant improvement and high satisfaction rates, they struggled to meet defined the minimal clinically important difference levels and patient acceptable symptomatic state scores that are used for a more general population.
      Dealing with a new technique in a small cohort of patients lends itself to several limitations and begs further questions. In terms of patient reported outcomes, it is unclear which portion of the procedure conferred benefits to the patients. This question pertains to both pain and instability. As reviewed above, there are many pain generators in the hip joint, so determining which procedure addressed pain is difficult to prove. With regard to increased stability, was it a result of the capsular plication or the LT reconstruction? Of the 3 patients who had a preoperative O’Donnell test recorded, only 1 had a negative test postoperatively. This test seems to be the most accurate test for LT dysfunction, with a sensitivity of 90% and specificity of 85%.
      • O’Donnell J.
      • Economopoulos K.
      • Singh P.
      • et al.
      The ligamentum teres test: A novel and effective test in diagnosing tears of the ligamentum teres.
      The authors incorporated this examination later in the study period, so though this may be an issue with a number of patients, it still begs the question of whether the reconstruction is achieving its goal of completely restoring the LT function.
      Overall, this study does much to further the conversation regarding stability of the hip and how we can continue to improve our techniques and understanding to advance the cause of hip preservation. This severe degree of hip instability presents a very difficult problem and patients’ expectations regarding outcomes must be carefully managed. This is still a quite specialized technique that is reserved for the most experienced hip arthroscopy surgeons, and I applaud Dr. Domb and his team for their efforts in increasing our knowledge and understanding in this area.

      Supplementary Data

      References

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