Introduction

Arthroscopic surgery of the hip has gained immense popularity during recent years as a minimally invasive and low-risk surgical procedure for the treatment of many intra- and extra-articular conditions in the hip. A resurgence of interest in sports medicine and a proficiency in arthroscopic techniques has led to an expansion of the indications for—and, in some cases, perhaps a stretching the limits of—this procedure. The latest trends seem to be accessing the peripheral compartment on a regular basis; arthroscopic excision of the cam femoroacetabular impingement lesion; labral detachment; rim trimming and labral refixation for pincer impingement; and the treatment of several extra-articular conditions, such as snapping hip and iliopsoas tendonitis.

Figure 23–7 Arthroscopic view of loose cement particles and florid synovitis.

Alternatively, resurfacing arthroplasty of the hip is also increasingly being performed worldwide, and the early to mid-term results warrant optimism. Early complication rates have decreased, and this seems to have become the procedure of choice for the younger patient with end-stage arthritis and good bone stock. However, problems do occur, and assessing the radiologically well-fixed but symptomatic resurfacing arthroplasty can be a difficult task. Soft-tissue problems such as adhesions, iliopsoas tendonitis, trochanteric bursitis, synovitis, sports hernia, and metallosis can occur around the resurfacing; these are extremely difficult to diagnose initially. Secondary bony or soft-tissue impingement can also be fairly symptomatic, and these conditions do not always show up on the radiographs. Finally, septic or aseptic loosening can also result in a painful resurfacing with minimal or no radiologic changes.

Therefore, despite thoroughly investigating the patient, a definitive diagnosis is not always possible. Undertaking a revision of the resurfacing is perhaps the only solution, even when it is not warranted. However, an arthroscopy of the symptomatic joint could be useful in this scenario. Arthroscopy has already been reported to provide a diagnosis and possible treatment of symptomatic joint replacements of the knee, the elbow, the shoulder, and, in some cases, the hip. Larger series are available that have described the results of knee arthroscopy after total knee arthroplasty, with varying results. Although treatment options are often limited, obtaining a definite diagnosis with the use of a minimally invasive approach is undeniably advantageous, precluding further major surgery. On the basis of these reports and the large arthroscopic experience of our unit, we performed arthroscopies for patients with these symptomatic resurfacings, and we found that the procedures can be of great diagnostic and therapeutic value. This chapter outlines our experiences with these challenging but interesting patients.

Indication

The sole indication for this procedure is a patient with a painful hip resurfacing in the presence of normal or indeterminate investigations.

History and physical examination

The assessment of a patient with a symptomatic resurfacing is quite challenging and should begin with a thorough history and physical examination. The patient typically presents with a history of pain in the buttock, groin, or thigh after the resurfacing. The character of the pain can provide some indication of the possible cause: a throbbing ache signifies underlying infection, whereas a sharp ache during weight bearing or start-up pain suggests possible implant loosening. The site of pain is also very helpful for determining the anatomic area of the possible pathology: pain in the buttock suggests problems with the acetabular component, whereas pain in the groin and the thigh suggests the femoral component. Patients who engage in strenuous physical or sports activity should be questioned about pain in and around the hernial orifices, because small sports hernias that are often missed can present with groin ache after a resurfacing. Patients with groin pain should also be questioned about the position or activity during which the pain is aggravated to elicit iliopsoas, adductor, or abductor tendonitis. Finally, referred pain from the lower back can also be a cause of pain in the buttock; a specific history that pertains to this pain should be elicited.

After a detailed history has been obtained, a physical examination that concentrates on the gait, the lower back, and the hip should be conducted. A limitation of the range of movement of the hip could be a result of soft-tissue or bony impingement lesions. The hernial orifices and the attachments of the iliopsoas, the adductors, the hamstrings, and the abductors should be palpated to ensure that pathology in these regions is not missed. Patients in whom there are clinical findings that are suggestive of sports hernias or muscle strains should be referred to a sports physician with an interest in groin pathology.

Investigations

The patient should be thoroughly investigated before this procedure is performed. Initial investigations should include a full blood count, an erythrocyte sedimentation rate, a C-reactive protein test to rule out infection, and a biochemical screen. For a patient with reported hypersensitivity, a full immunologic screen and a referral to an immunologist or a physician with experience in this arena is warranted. Radiologic investigations should include plain anteroposterior and lateral radiographs of the affected hip and an isotope bone scan, which is helpful for identifying the early loosening of the components. For a patient with a suspected sports hernia or groin strain, an ultrasound scan of the groin and occasionally a magnetic resonance scan with metal-suppression sequences is beneficial. The magnetic resonance scan can also be helpful for identifying edema around the trochanteric bursa, the iliopsoas tendon, and the adductor tendons, if there is pathology in these areas. Finally, a diagnostic local anesthetic block can help to elucidate whether the pain is intra- or extra-articular in origin.

Surgical technique

The operation is performed as a day-care procedure with the patient under general anesthesia or with the use of a combination of a general anesthetic and a lumbar plexus block. We prefer to have the patient in the lateral position, but the supine position can also be used. The patient is placed in the lateral decubitus position, and appropriate abduction, flexion, and longitudinal traction are obtained with a distractor that can be attached to a standard Maquet table. The image intensifier is placed obliquely across the patient, and images of the resurfacing arthroplasty are obtained. It should be kept in mind that a large amount of longitudinal traction is not necessary for this procedure. Therefore, the hip is distracted to about 1 cm under fluoroscopic control, and a 17-gauge spinal needle is inserted into the joint. This allows for the negative intra-articular pressure to be equalized with the atmospheric pressure, and it also allows for the mandatory aspiration of the synovial fluid for culture before saline is instilled in the joint.

Standard lateral paratrochanteric and anterior paratrochanteric portals are made to access the central compartment; this allows for the visualization of the edge of the acetabular component, the bone–component interface (Figure 23-1), and the synovial membrane, and the surgeon is also able to look for any possible metallosis. If debridement is required, it is performed with an arthroscopic shaver or a radiofrequency probe. Synovial biopsy and further aspirates from the bone implant interface may also be obtained at this time.

Figure 23–1 Arthroscopic view of the bone–implant interface.

Releasing the traction completely and flexing the hip to relax the anterior capsule allows for easy access to the peripheral compartment of the arthroplasty. The main portal for the peripheral compartment is made approximately 4 cm anterior and superior to the direct lateral paratrochanteric portal. Entry into the peripheral compartment allows for the visualization of the base of the femoral component (Figure 23-2) for assessing component stability. It also provides an opportunity to diagnose and treat capsular pathology, fibrosis, adhesions (Figure 23-3), iliopsoas tendonitis (Figure 23-4), and soft-tissue and bony impingement lesions (Figure 23-5).

Figure 23–2 Arthroscopic view of bone resorption at the base of the femoral component, with a bone spike in the resorbed area.

Figure 23–3 Arthroscopic view of a thick fibrous band seen in the peripheral compartment. This band causes pain and restriction of the range of motion.

Figure 23–4 Arthroscopic view of iliopsoas tendonitis in the peripheral compartment.

Figure 23–5 Arthroscopic view of a bony impingement lesion in the peripheral compartment.

However, the greatest advantage of arthroscopy for resurfacing lies in its dynamic component. The dynamic component involves the internal and external rotation of the hip during flexion, which leads to the micromovement of the acetabular component or the femoral component if either one is loose. A ring-handle spike or the arthroscopy hook can also be used at this stage to assess the stability of the components.

Postoperative rehabilitation

As mentioned previously, the operation is carried out as a day-care procedure. If there is no obvious sign of infection during arthroscopy, we inject the joint and the portal sites with 20 mL of 0.5% Chirocaine for postoperative analgesia. Oral analgesia is also prescribed on a regular basis for the first week after surgery. The patient is mobilized with the use of partial weight bearing with crutches 3 to 4 hours after the operation. When the patient is mobilizing safely, he or she can be discharged from the ward.

When the patient is out of the hospital, our rehabilitation protocol includes a program of exercises to reestablish a full and pain-free range of motion. This involves progressing from partial weight bearing to full weight bearing after the prescribed period of crutch use within the limits of pain; the process usually lasts for approximately 4 weeks. Gait reeducation is essential for all patients, because surgery almost always follows prolonged pain and dysfunction. This can lead to altered biomechanics of the lower limb and abnormal movement patterns, which need to be assessed and corrected after surgery.

Gym-based rehabilitation is arranged at this stage and commonly involves a static cycle, an elliptical trainer, and a treadmill. Further progressions and resistance are added at the therapist’s discretion. Hydrotherapy and swimming are begun after the wound has healed. The patient is reassessed at 2 weeks by his or her personal physician and then at 6 weeks at our clinic, where further management is discussed.

Results

Twelve consecutive patients with painful resurfacing and normal or indeterminate investigations underwent arthroscopy of the hip in our unit. There were 8 female patients in the series, and the mean age of the patients was 53.7 years (range, 38 to 70 years). Seven patients had a fully uncemented hydroxyapatite-coated resurfacing arthroplasty (Cormet 2000, Corin Medical Ltd., Cirencester, UK), and 5 patients had a hybrid BIRMINGHAM HIP Resurfacing procedure (Midland Medical Technologies Ltd., Birmingham, UK). The mean period from the index operation to the arthroscopy was 25 months (range, 6 to 48 months). More complete details about all of the patients and their intraoperative diagnoses and treatments are shown in Table 23-1.

Two of the 12 patients were suspected of having an aseptic loosening of the acetabular component, but there was no obvious osteolysis apparent on the plain radiographs to confirm this (Figure 23-6). One of these patients was found to have that condition during arthroscopy, but both of the patients were revised to an uncemented total hip replacement; the femoral component, although well fixed, showed osteolysis at the base. None of the cultures of the aspirates sent at arthroscopy came back as being positive.

Figure 23–6 Radiograph of a patient 3 months after a resurfacing arthroplasty. The patient is symptomatic, but there is no apparent osteolysis.

Complications

The procedure is relatively safe, and we did not have any complications in our series. However, apart from the general complications of hip arthroscopy related to traction, one has to be extremely vigilant during the insertion of instruments into the joint to avoid the iatrogenic scratching of the surfaces of the femoral and acetabular components. In addition, it should be kept in mind that a large amount of traction is not required for this procedure, thus circumventing the complications that could arise as a result of traction. Finally, one has to be vigilant while inserting wires into the resurfaced joint, because there is a high possibility of breaking them, and removing them is certainly not a task for the amateur.

Conclusion

The assessment of a symptomatic resurfacing is usually difficult, and it becomes more challenging in the setting of normal or indeterminate investigations. However, we found that, in experienced hands, hip arthroscopy can be used as an effective tool for both diagnosis and therapeutic intervention for these patients.

Further possibilities of an arthroplasty include assessing polyethylene wear; replacing misplaced liners of the acetabular components; performing arthroscopically assisted revision hip replacements by allowing for easy access to the femoral canal for the retrieval of cement; performing sequestrectomy for infection; and excising recurrent synovial osteochondromatosis that may occur despite an arthroplasty.

It is important to note that resurfacing remains a highly specialized procedure that should not be undertaken without appropriate training.