History of hip arthroscopy
Hip arthroscopy is a minimally invasive therapeutic and diagnostic procedure which is routinely used for the treatment of intra- and extra-articular pathology of the hip including femoroacetabular impingement (FAI), labral and chondral pathology, ligamentum teres injuries, synovial chondromatosis, internal snapping hip, sub-spinous impingement, gluteus medius tears, and the indications are ever expanding.[1,2] Its popularity has risen dramatically over the past two decades since the association between FAI and osteoarthritis was first described by Ganz et al. Between 2002 and 2013, there was more than a 7-fold increase in the number of arthroscopic hip procedures being performed in the UK. This trend is mirrored in the United States, where femoroplasty, labral repair, and acetabuloplasty are the three most common hip arthroscopic procedures performed. This upward trend in hip arthroscopy is predicted to increase into the coming decade, and anecdotally, it continues to rise.[1,5] In this article we have highlighted the major breakthroughs which led to the development of hip arthroscopy [Figure 1].
EARLY YEARS – PROBLEMS WITH ACCESS
Hip arthroscopy was first described in 1931 by Michael Burman [Figures 2 and 3], however, its widespread adoption was only achieved some 60 years later during the 1990s.[6,7] The hip joint is a deep-seated joint, with limited maneuvrability, due to high congruency within the joint. These features of the hip which provide inherent stability actually hinder arthroscopic visualization. Thus, widespread implementation of this technique was only possible once technical advances allowed adequate distraction of the femoral head from the acetabulum, providing sufficient access for arthroscopic access to the hip joint. The characteristics of the hip precluded it from early investigation by endoscopy, which was developed to gain internal visualization of other body cavities including the respiratory, urinary, and gynecological tracts. These endoscopes were then adapted for the development of arthroscopy during the 20th century.
The earliest endoscopic efforts are detailed in archaeological records from Ancient Rome, detailing optimal lighting conditions and patient positioning. However, it is Dr. Phillip Bozzini who is credited as the founding father of modern- day endoscopy. In the early 19th century, the Italian physician developed the “Lichtleiter” [Figure 4]. It consisted of a wax candle held by springs fortified with a system of double aluminum tubes and mirrors to allow separate lighting and imaging. This demonstrated adequate lighting and penetration through the use of different light and reflection conduits for different cavities. The clinical use of the Lichtleiter is heavily debated, with some sources claiming it was only ever used to examine canine bladders. Other accounts report successful use by physicians in diagnosing pathologies including anal fistulas and vaginal canal lesions and that it was utilized in military hospitals after presentation to the Vienna-Joseph’s Academy in 1805.
Bozzini’s contribution was the first of its kind and paved the way for continual endoscopic improvements during the 19th century. Similar endoscopes were designed to inspect the vagina, bladder, and urethra some 20 years later by both the French physician Segalas and the American physician Fisher. These devices afforded improvements in the light sources and optics of these primitive endoscopes.
After various iterations, primitive endoscopes had been developed for visualization of internal anatomy, and numerous cystoscopic lithotripsy case reports emerged. A turning point was reached in 1853 when Désormeaux presented an endoscopic device to the Academy of Science in Paris, which provided improved internal illumination through the use of a gasogene lamp, using a mixture of alcohol and turpentine. This device enabled the first reported endoscopic therapeutic surgical procedures to be performed, including endoscopic excision of a urethral papilloma. Iterative improvements in endoscope design continued, providing the basis for improvements in surgical technique as direct visualization of anatomy during endoscopic surgical excision became possible.
The year 1877 marked the beginning of modern endoscopy as Maximilian Carl-Friedrich Nitze, a German urologist, presented a cystoscope which utilized an electrified light source and a wide-angle lens. The improved field of view enabled visualization of anatomy outside of the aperture of the cystoscope. Nitze reported 150 cases of cystoscopic bladder tumor removals, marking the development of the first practical operating cystoscope. These cystoscopes, and subsequent designs, were realized for their potential and used for a variety of exploratory and surgical procedures beyond their original scope. These included, for example, exploration of the pleural (thoracoscopy) and peritoneal (laparoscopy) cavities pioneered by Jacobaeus. It would be over half a century until this technology would be applied to the visualization of joint cavities: Arthroscopy.
Efforts to translate endoscopy to arthroscopy were made by two pioneering surgeons, The Dane Severin Nordentoft, and the innovative Japanese professor of surgery Kenji Takagi. Nordentoft influential/widely recognized christened the term “arthroscopy” during his presentation to the 41st Congress of the German Society of Surgeons in 1912 and proposed this technique “arthroscopia genu” to visualize meniscal lesions. Nordentoft, however, did not continue his work in knee arthroscopy. In 1918, Takagi [Figure 5] began his efforts using a small cystoscope to visualize the knee joint in cadavers. This research work was conducted at a time where TB inflicted devastatingly high mortality and morbidity. A tuberculous knee usually resulted in ankylosed or stiff knee, conferring social and physical disability in a society where kneeling and bowing had an important cultural significance. In his quest for early detection of tuberculous arthritis, he is typically credited as being the first to advocate knee arthroscopy. Takagi sequentially developed more refined arthroscope, reducing the diameter from 7.3 mm to 2.7 mm over the span of 11 models.
Takagi did not publish his findings until 1933 after presentation at the Japanese Orthopaedic Association. During this period, a Swiss surgeon named Dr. Eugen Bircher utilized the Jacobaeus laparoscope for visualization of the knee joint and was the first to publish on the subject. The instrument was not well suited for knee arthroscopy due to a 90° optic and dead space between the lens and the tip of the instrument. Nevertheless, he published two classic articles in 1921 and 1922 in German illustrating the procedure, which utilized nitrogen gas to distend the joint in which he observed post-traumatic arthritis and meniscal pathology. Following this, American arthroscopy pioneer Burman propagated the technique in the US using forward facing optics, after a 1930 fellowship in Berlin studying endoscopy. He attempted to study almost every joint in the body using a 3 mm arthroscope in cadavers and published 4 times on the subject between 1931 and 1936.[6,17-19] His 1931 publication represents the first documented arthroscopic exploration of the hip. He performed few hip studies after noting visualization was limited to only the articular surface of the femoral head and intracapsular surface of the femoral neck – the peripheral compartment described in modern hip arthroscopy. He further noted that the hip joint should be examined using a thinner arthroscope than his apparatus, which had a sheath with total outside diameter of 4 mm. He postulated that it would be impossible to insert an arthroscope between the acetabulum of the pelvis and the femoral head – meaning the labrum, and ligamentum teres would not be seen.[6,20] The idea that the modern central compartment could not be accessed may have contributed to the stagnation seen in the field of hip arthroscopy, as techniques were developed for arthroscopic exploration of the knee in the following half century.
Takagi produced the first colorized images of the inside of a knee joint in 1936 and performed the first therapeutic arthroscopic treatments of Charcot’s joints, tuberculous, and infective arthritis. He detailed these achievements in his 1938 presentation to the Japanese Orthopaedic Association, discussing clinical details of 57 cases.[20,21] It was not until WWII ended that there was a resurgence in arthroscopy progress. A Japanese surgeon and former student of Takagi, Masaki Watanabe, continued Takagi’s work in arthroscope development. He produced 24 further models and performed his first surgical procedure under arthroscopic control in 1955: Removal of a xanthomatous giant cell tumor under arthroscopic control. He went on to publish an “Atlas of Arthroscopy” in 1957, and his No. 21 arthroscope [Figure 6], developed in 1958, became the first production arthroscope.[14,20] Dr. Watanabe presented his color movie “arthroscopy” at the seventh International Society of Orthopaedics Surgery and Traumatology (SICOT) congress in 1957 and subsequently at many centers in Europe and North America. Despite a good reception, arthroscopy did not receive high uptake after Watanabe’s tour of the West, and he received no communication regarding arthroscopic practice. Watanabe has subsequently been credited with the development of modern arthroscopy for this work and continued contributions to the field.
Seven years later, Dr. Robert Jackson traveled to Japan as part of a scholarship to study tissue culture at Tokyo University. He took great interest in Watanabe’s work and spent time training under him. Upon Jackson’s return to Toronto, Canada, he was invigorated with the possibilities of the No. 21 arthroscope which he bought on his return. He first formally presented his arthroscopy practice in 1967, at the inaugural meeting of the Association of Academic Surgeons held in Toronto. From 1968 to 1972, Jackson instructed many courses in arthroscopic surgery at the American Academy of Orthopaedic Surgeons, which proved successful. Some of his students went on to pioneer arthroscopic techniques across the country, including Dr. Ward Casscells and Dr. Jack McGinty. Meanwhile in Europe, the popularity of arthroscopy was also rising. In 1975, Harold Eikelaar published his thesis on arthroscopy of the knee in Holland, and 1 year later, the first English monograph on the subject of knee arthroscopy was published.[22,23]
A new spread of awareness manifested with the foundation of the International Arthroscopy Association in 1974. Watanabe was elected as its first president. It served as a body to educate orthopedic surgeons and a number of learning courses were developed under its wing. In the late 1970 and 1980s, a few prominent surgeons spearheaded the progression of hip arthroscopy. This came after labral tears were recognized as a cause of disabling hip pain and were suggested to be part of the degenerative process in 1977. Subsequently, in 1986, Suzuki et al. documented the use of arthroscopy to aid the diagnosis of acetabular labral tears not visible by arthrography. Progression in surgical techniques and specialized equipment then ensued.
James Glick, a surgeon in San Francisco, carried out a substantial amount of work to progress surgical technique. He published an article in 1987 detailing the insertion of an arthroscope into the hip joint through the lateral approach while the ipsilateral hip is abducted and flexed with traction being exerted appropriately. The use of distraction was a significant development in the utility of hip arthroscopy and paved the way for future increase in the procedure through enabling visualization of the central compartment. In the mid-1980s, the Cambridge surgeon Richard Villar corresponded with Glick and a number of other authors who had published on the subject including Hawkins. Villar published the first textbook on the topic of Hip Arthroscopy in 1992 and mentored a number of surgeons in the UK and internationally, including the senior author, with the lateral approach to hip arthroscopy. Richard Villar later became the founding member and first president of the International Society for Hip Arthroscopy (ISHA) in 2008 [Figure 7].
The establishment of ISHA proved to be a pivotal step in sharing knowledge around this seemingly unfamiliar procedure in the field of orthopedics, and throughout the 1990s, several manuscripts were published thereby helping advance arthroscopic surgical techniques.[28-31] Entry to the 21st century saw hip arthroscopies being performed regularly at many centers around the world. As with any health intervention, surgeons must weigh up benefits versus complications and other limitations before adopting a technique. This is especially true for hip arthroscopy which is widely regarded to have a steep learning curve.
Hip arthroscopy is known to aid in the diagnosis of hip disease, specifically in relation to intra-articular disease in young patients which can be a challenging area for orthopedic surgeons. This is exemplified in the case of FAI and associated intra-articular pathology. FAI is a condition resulting in abnormal contact between femoral head-neck junction and acetabular rim, which may cause labral and chondral lesions in the anterosuperior region of the acetabulum due to repetitive microtrauma. FAI can be classified as cam, pincer or mixed types.
While plain radiographs have poor value in the assessment of intra-articular pathology, they are still a valuable investigation for the assessment of FAI by evaluating femoral and acetabular bony abnormalities. MRI remains the gold standard option as a non-invasive imaging diagnostic procedure. It has a reported sensitivity of 85–90% for labral tears and 91-92% for chondral damage.[34,35] However, in comparison to arthroscopic examination, it has a reported specificity of 70% for labral tears and 62% for chondral lesions. Such findings demonstrate that invasive imaging techniques including arthroscopy and magnetic resonance arthrography (MRA) maintain a key diagnostic role for intra-articular pathology. MRA is better at identifying labral pathology, as intra-articular gadolinium contrast medium is administered. It achieves a high sensitivity and specificity for labral tear identification of 95% and 92%, respectively, and of 94% and 91%, respectively, for chondral lesions. Despite the success of invasive imaging, arthroscopy still retains a diagnostic role, albeit limited, especially in the case of undiagnosed hip and groin pain where all the investigations are equivocal, and it is the gold standard test for the identification of intra-articular pathology.
Hip arthroscopy is a surgical intervention used in the management of many hip-related pathologies and shows high patient satisfaction and overall success rates. In the case of FAI, arthroscopic surgical intervention can be utilized for osseous correction through femoroplasty or acetabuloplasty, and labral and chondral damage can be addressed. The osseous correction will decrease head-neck offset or reduce acetabular over coverage of the femoral head, thereby restoring hip joint function. In this setting, hip arthroscopy provides significant improvements in general and hip-related quality of life scores postoperatively in patients without advanced OA. While arthroscopy still produces positive outcomes in some individuals with OA, its efficacy is reduced. A more rapid progression to total hip arthroplasty is observed in those with severe chondropathy and advanced age. Such findings highlight the importance of early detection for conditions which predispose to OA, and the advances in arthroscopy has enabled in their diagnosis and management.
While hip arthroscopy has positive outcomes, a comparative overview is required when considering the efficacy of a treatment option. A number of studies contrast hip arthroscopy with traditional hip arthrotomy and conservative management. Some clinicians may prefer non-operative management which includes physiotherapy, intra-articular steroid injections, or active monitoring. These options have been outlined in the Warwick agreement regarding the management of FAI as part of an appropriate management pathway. It has been shown, however, that patient-reported outcome measures (PROMs), including non- arthritic hip scores (NAHS) and modified Harris hip score, are significantly higher in FAI treated using hip arthroscopy compared with physiotherapy.[40,41] In a large multicenter RCT, hip arthroscopy showed an iHOT-33 (PROM) score 6.8 points higher than physiotherapist-led conservative care when adjusted for baseline score and patient characteristics at primary outcome assessment, representing a clinically significant difference.
Hip arthroscopy outcomes are also favorable in comparison to hip arthrotomy with open surgical dislocation, which is also a surgical option for surgical management of FAI. Patients who underwent hip arthroscopy scored significantly higher NAHS at 3 and 12 months follow-up and also reported to have a lower rate of revision. However, other PROMs at 12-month follow-up did not differ significantly between the procedures. This may indicate the benefits of the decreased recovery time hip arthroscopy offers. It is known that there are complications and risks associated with joint dislocation including an increase in the rate of infection, deep vein thrombosis (DVT), and avascular necrosis. Furthermore, the minimally invasive surgery approach affords reduced blood loss, soft-tissue damage, scarring, and improved post-operative capsule integrity. Conversely when compared to open surgical dislocation, hip arthroscopy provided a significantly lower reduction of the alpha angle measured by the Dunn lateral view for individuals with cam deformity. This is likely due to the surgeon’s assessment of the lesion using 2D modalities, including the arthroscopic appearance and fluoroscopy. Navigated surgery techniques, however, are able to reduce the rate of arthroscopic under- resection. While there is not total agreement in the literature, hip arthroscopy has been adopted by the majority of surgeons over open arthrotomy.
There are, however, a number of other conditions which report better outcomes when treated with open surgery versus hip arthroscopy. These include acetabular dysplasia, Legg-Calve-Perthes disease, and chronic slipped capital femoral epiphysis. Such cases illustrate the importance of astute patient selection for surgery. Hip arthroscopy has many benefits over traditional hip surgery which is exemplified in the management of FAI, but it should not be considered the default procedure for every patient with intra- articular pathology.
Hip arthroscopy is a successful technique, although a wide range in complication rate has been reported. A recent systematic review of observational studies determined the complication rate of hip arthroscopy to be 3.32%. The three most common complications were neuropraxia, iatrogenic chondral and labral injury, and heterotopic ossification with rates of 0.92%, 0.69%, and 0.60%, respectively. Major complications made up 4.8% of all complications, and the most common major complication was abdominal fluid extravasation.
Emphasis is placed on the importance of patient selection to achieve favorable complication rates for hip arthroscopy. Obese, older, and dysplastic females have the worst reported post-operative outcomes from hip arthroscopy. Obesity is also a known risk factor for the development of osteoarthritis, and it has now been demonstrated that there is a lower overall outcome and a higher rate of revision surgeries in the obese. Given obesity is becoming an increasingly prevalent problem worldwide, physiotherapy and weight loss may be advised before considering a surgical solution. In addition, within groups of females with FAI separated according to age and bony characteristics, older patients with borderline dysplasia had poorer iHOT-12 scores compared to other groups. Such patient risk factors may guide a surgeon’s management decision.
Other non-specific complications of hip arthroscopy include DVT which has a likelihood of 4.3%. However, routine thromboprophylaxis is not advocated by everyone, thereby requiring the surgeon to assess the risk of venous thromboembolism on a case-by-case basis and institute appropriate mechanical and/or chemical thromboprophylaxis. Other less frequent complications include femoral neck fractures. Despite decreased complication rates in high-volume surgeons, no correlation has been shown between the number of hip arthroscopies a surgeon had performed and the rate of hip fracture as a complication.
The British Non-Arthroplasty Hip Register (www.nahr.co.uk) recorded a 250% increase in hip arthroscopies performed between 2007 and 2011. This increase in popularity has presented many advantages as well as some drawbacks. It is commonly acknowledged that there is a steep learning curve associated with hip arthroscopy. During the learning of this procedure, there is a significantly higher complication rate in the first 30 patients, and operative time decreases as the number of arthroscopies performed increases. It has been suggested that the complication rates in low-volume surgeons are unacceptably high, which raises an ethical dilemma for the adoption of the procedure. A plausible solution would be to encourage more orthopedic surgeons to adopt hip arthroscopies into their work, and for learning to occur only at specialist centers, where there is adequate supervision to optimize practice and training. There is also an emerging role for virtual reality simulation of hip arthroscopy in the training of surgeons. This has demonstrated a significant improvement in surgeon performance after three sessions.
New technologies in theater prove challenging for surgeons. This is especially true for minimally invasive surgery (MIS) where there is a more demanding work environment and there are less rigorous safety and testing standards for instruments compared to similar medical industries such as pharmaceuticals. Studies show that recently trained surgeons are more likely to use MIS techniques, with a gradual shift in the operative techniques utilized. Furthermore, it appears to be beneficial to invest in the training of the supporting surgical team.
The journey of hip arthroscopy has been impressive and it is certainly here to stay. However, hip arthroscopy provides clear positive outcomes only when patients are correctly stratified and selected, and in the hands of an experienced operator. The future holds new exciting possibilities for hip arthroscopy both in terms of technological advances in helping better stratification of disease, accuracy of the procedure (robotics) and training (simulators), and also biological advances helping with addressing the damaged articular cartilage.
Declaration of patient consentPatient’s consent not required as patients identity is not disclosed or compromised.
Financial support and sponsorshipNil.
Conflicts of interestThere are no conflicts of interest.
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