Hip pain in young people: the principles and evolution of hip joint preservation and salvage surgery

Hip pain in young people was traditionally treated with operations aimed at altering the anatomy of the joint so that it more closely resembled a normal hip. However, with the introduction and development of total hip arthroplasty, particularly in older patients and offering impressive results for patients in terms of pain, hip preservation and salvage techniques were neglected or even abandoned. The result was that most patients with chronic hip pain came to be treated with total arthroplasty, while the remaining cases were managed conservatively. This also had an impact on the training of orthopaedic surgeons, and particularly of those with a special interest in the hip, as many orthopaedic surgeons have never seen, or have not been adequately trained in, hip preservation and salvage techniques. As a result, the new generation of hip surgeons has perhaps greatly widened the indications for total arthroplasty and regards only a very small proportion of patients with chronic hip pain as candidates for hip preservation and salvage surgery.
The development of hip arthroscopy has helped, either indirectly or directly, to identify further factors considered responsible for chronic hip pain, such as a tear of the labrum. At the same time, the emergence of the syndrome of femoroacetabular impingement, which came to light only a few years ago, reminded hip surgeons once again that pain is not due solely to the degenerative process and the partial or complete destruction of the joint, but may also be due to anatomical variants and abnormalities, which could be treated early so as not only to abolish the symptoms of pain and stiffness, but also to prevent further deterioration of the joint.
The first attempts at such operations involved osteotomies, by which an effort was made to restore the normal anatomical axis of the femur. Unfortunately, at that time the techniques of internal fixation and stabilisation had not yet developed, and so the operation often resulted in an osteotomy next to a rather stiff joint, which led to the formation of a mobile pseudarthrosis. One of the first attempts at internal fixation involved the use of the Smith-Petersen nail, introduced in 1925. Various techniques for the fixation and stabilisation of osteotomies were subsequently developed, and in the years that followed trans- and subtrochanteric osteotomies evolved, which could be adequately stabilised with new implant materials. This development was interrupted at around the 1980s, when total hip arthroplasty appeared and came into widespread use.
Even so, there were many advocates of hip preservation and salvage techniques who persisted in believing that surgery on the hip should not be performed only in cases where there is extensive wear and destruction of the joint, but earlier as well, in order to correct features of its anatomy. In this way a school of practice devoted to these techniques was maintained, whether through open surgery, through minimally invasive surgery or even through the arthroscopic technique.
Femoroacetabular impingement is perhaps the classic example of the importance of joint preservation and salvage surgery, since it is an anatomical abnormality that predisposes to pain and to progressive wear of the joint. Cam-type femoroacetabular impingement is an anatomical abnormality of the femoral head-neck region, which shows so-called femoral hyperostosis. Radiologically this lesion is described as a pistol grip deformity. This abnormality disturbs the congruity between the acetabulum and the femoral head, particularly at the extremes of hip movement. Many of these cases are thought to have been caused by silent slipped capital femoral epiphyses during adolescence. The observation that cam-type femoroacetabular impingement can lead to early osteoarthritis has brought about a change in the proportion of cases of hip osteoarthritis classified as secondary, since primary or idiopathic cases of hip osteoarthritis, that is, those not caused by a significant anatomical abnormality or by a femoroacetabular impingement lesion, account for only 10-15% of cases. The second form of femoroacetabular impingement is the cam type, in which there is increased anterior tilt of the acetabulum (retroversion) or a deep acetabulum (coxa profunda), and which essentially produces the same lesions as cam, that is, impingement of the femoral neck against the acetabular rim and injury to the labrum. The labrum is progressively injured more and more, until it reaches a point of severe degeneration and finally perhaps of disappearance. This is the initiating cause of the destruction of the joint. Femoroacetabular impingement can be treated surgically, either by an open surgical technique or by hip arthroscopy. The aim of the operation is removal of the femoral hyperostosis in the case of cam, or removal of the excess bone at the acetabular rim (acetabular recession). In addition, resection, repair or even reconstruction of the labrum may be carried out when it has been damaged.
In the case of slipped capital femoral epiphysis in adolescence or pre-adolescence, the problem can be treated by fixation with pins, by reduction followed by fixation or, in some cases, by an osteotomy of the femoral neck or even of the femoral head. Finally, in cases of hip dysplasia with a shallow acetabulum and inadequate cover of the femoral head, there is a place for acetabular osteotomies aimed at changing its orientation and also at creating greater cover, so that the femoral head is stabilised.
The new philosophy of hip preservation and salvage techniques places greater emphasis also on ways of preserving the features of the microanatomy of the joint, that is, the labrum, the articular cartilage, the ligamentum teres and so on. Perhaps the most complete method of preserving the hip joint is the simultaneous correction of the principal axes and angles of the joint together with the preservation, correction or even regeneration, through the new biotechnological techniques, of the microstructures of the joint and in particular of the articular cartilage. Hip arthroscopy opens a new horizon in this direction.
Source: The Bone and Joint Journal, January 2014 issue