Similar to the knee joint, the key to an accurate and complete diagnosis of lesions within the hip joint is a systematic approach to viewing. A methodical sequence of examination should be developed, progressing from one part of the joint cavity to another and systematically carrying out this sequence in every hip.
For arthroscopic examination, the peripheral compartment of the hip can be divided routinely into the
following areas: anterior neck area, medial neck area, medial head area, anterior head area, lateral head area, lateral neck area, and posterior area. From my experience, the peripheral compartment can be best viewed during a diagnostic round trip starting from the anterior surface of the femoral neck (Figure 11.8). Under slow rotation and sliding of the arthroscope over the femoral neck and head, the arthroscope is brought into the different areas of the peripheral compartment of the hip.
Entering the peripheral compartment from the an-terolateral portal the scope is lying on the anterior surface of the femoral neck. The first view (see Figure 11.8 A) allows inspection of the anterior and medial neck area with the anterior and medial synovial folds, the anteromedial surface of the femoral neck, the an-teromedial part of the zona orbicularis, and the liga-mentum iliofemorale (Y-shaped ligament of Bigelow). With the 25-degree lens of the arthroscope directed medially, a medial synovial fold (iliopectineal fold)13 can be found consistently. It is usually not adhering to the femoral neck and passes proximally from the medial border of the femoral head distally to the lesser trochanter. This structure is a helpful landmark, especially if visibility within the peripheral compartment is limited by synovial disease.13 The anterior synovial fold is adherent to the neck and only recognizable by its single fibers covering the bone of the neck. It can be partially torn by entering the joint with the sharp trochar, which should be avoided by using blunt instruments. Anatomic dissections showed that 80% to 90% of the synovial folds contain small branches of the circumflex femoral arteries.54 In each fold, one to three small arteries with a mean cross-sectional area of 0.13 mm2 for the anterior fold and 0.18 mm2 for the medial fold were found. Larger ves sels were found in the lateral fold. Even if the major blood supply to the femoral head comes from the posterior branches, tearing of the folds should be avoided to decrease intraarticular bleeding. Dorfmann reported that he has seen local inflammation and hypertrophy of the medial synovial fold, which may be the sequelae of a chronic impingement of the fold between head, neck, and zona orbicularis.52 Resection of the fold leads to improvement.
By rotating the arthroscopic lens cranially, the anterior margin of the femoral head, the anterior recess with the anterior capsule, and the zona orbicularis (see Figure 11.8B) can be inspected. Caudally, a complete view to the inferior reflection of the articular capsule at the intertrochanteric crest can be achieved with the 70-degree lens (see Figure 11.8C). Here, the articular cavity should be scanned for loose bodies. Biopsies of the synovium can be taken easily without a risk to labrum and cartilage via portals that are placed in the anterior or the anterolateral zone.
Moving the scope medially over the medial synovial fold, the medial neck area can be examined. By rotating the 25-degree lens, the medial margin of the femoral head, the medial wall of the capsule with the zona orbicularis and the medial recess can be inspected. Rotating the lens downward, the zona orbic-ularis vanishes posterior to the femoral neck. By external rotation of the hip joint, a larger area of the posteromedial surface of the neck and head can be inspected. Changes in hip position, a short period of high-flow irrigation, and use of a suction forceps via the additional working portal or manual ballotement from posterior may be necessary to bring loose bodies from posterior into the medial or anterior recess. The 70-degree lens is replaced by the 25-degree lens and directed upward to the medial head area.
FIGURE 11.8. Diagnostic round and arthroscopic anatomy of the peripheral compartment of a right hip. (A) Anteromedial neck area: medial synovial fold (msf), femoral head (fh), femoral neck (fn), anteromedial capsule with the zona orbicularis (zo). (B) Upward view to the junction between the anterior neck and head area: anterior cartilage surface of the femoral head (fh), anterior part of the zona orbicularis (zo), anterior capsule (ac), free edge (fe) of the zona orbicularis. (C) Anterior neck area: downward view with the anterior synovial fold (asf) and reflection of the capsule at the intertrochanteric crest (ic). (D) Medial head area: articular surface (as) and cartilage-free surface (cfs) of the medial femoral
FIGURE 11.8. Diagnostic round and arthroscopic anatomy of the peripheral compartment of a right hip. (A) Anteromedial neck area: medial synovial fold (msf), femoral head (fh), femoral neck (fn), anteromedial capsule with the zona orbicularis (zo). (B) Upward view to the junction between the anterior neck and head area: anterior cartilage surface of the femoral head (fh), anterior part of the zona orbicularis (zo), anterior capsule (ac), free edge (fe) of the zona orbicularis. (C) Anterior neck area: downward view with the anterior synovial fold (asf) and reflection of the capsule at the intertrochanteric crest (ic). (D) Medial head area: articular surface (as) and cartilage-free surface (cfs) of the medial femoral head, anterior horn of the labrum (arrowhead), perilabral sulcus (pls), transverse ligament (tl). (E) Anterior head area: cartilage of the femoral head (fh), free edge of the labrum (fe), base of the labrum (b), perilabral sulcus (pls). (F) Lateral head area: cartilage of the femoral head (fh), lateral portion of the labrum (l), perilabral sulcus (pls). (G) Lateral neck area: lateral margin of the femoral neck (fn) and head (fh); lateral synovial fold (lsf) building a small subplical pouch (p), zona orbicularis (zo). (H) Posterior area: posterior surface of the femoral head (fh), posterior labrum (pl), perilabral sulcus (pls), thin posterior capsule (pc). (Reprinted with permission from Dienst et al.43)
If the patient is not obese, the standard scope can be moved medially into the medial head area. Otherwise, longer scopes must be used. At the medial corner of the joint, inspection of the anterior horn of the labrum and the anteromedial part of the transverse ligament is possible (see Figure 11.8D). The labrum is close to the chondral surface of the femoral head. A small gap or synovium can be seen between the femoral head and the transverse ligament, which connects the base of both horns and both edges of the lunate cartilage.
By gentle rotation, sliding tangentially over the cartilage of the femoral head and withdrawing the arthro-scope, the labrum and anterior cartilage of the femoral head can be inspected from the medial to the anterior and lateral head area (see Figure 11.8E). The more the hip is flexed, the more the labrum is lifted from the head, which allows a partial inspection of the central compartment. In particular, the labrum has to be probed for labral cysts and tears, which are most frequently found in this location. A shaver or elec-trothermic instruments can be slid underneath the labrum and debridement of the labrum can be performed. Cysts can be decompressed.
Moving the arthroscope laterally to the lateral head area can be hindered by a tight zona orbicularis. Flexion of the hip up to 45 degrees, with 20 to 40 degrees of abduction and slight external rotation of the hip, may ease passing of the arthroscope, thus allowing inspection of the lateral part of the labrum and cartilage of the head (see Figure 11.8F). Alternatively, the scope can be withdrawn distally to the neck for inspection of the lateral neck area first. Then the scope is moved forward to the lateral head area.
From an anterolateral portal, sweeping directly along the lateral side of the femoral head down into the posterior area is hindered by the zona orbicularis. Consequently, the scope is withdrawn distally to the circular fibers of the capsule and the lateral neck area is inspected first (see Figure 11.8G). Here, the zona or-bicularis can be seen running posteriorly around the neck. A lateral synovial fold can be seen quite consistently. This fold runs from the greater trochanter upward along the lateral side of the neck to the lateral margin of the head. It is often posteriorly adherent to the neck and forms a small pouch. Thus, the lateral fold is not as prominent as the medial one. Anatomic dissections have revealed that the lateral fold contains small arteries of larger diameter (mean, 0.28 mm2) than the anterior and medial fold.54 As recommended for the other folds, tearing of the folds should be avoided.
Access to the posterior area can be achieved by moving the scope straight posteriorly between the zona or-bicularis and the lateral synovial fold. After insertion of the 70-degree lens, the posterolateral and lateral part of the labrum, head, and neck and the posterior syn-ovium can be inspected (see Figure 11.8H). The lateral and the posterior areas are more difficult to inspect compared with the anterior and medial areas. Hypertrophy of the synovium and tight joints (e.g., osteoarthritic hip joints with capsular fibrosis) can significantly decrease orientation and mobility for passing the arthroscope to the lateral and posterior areas. In addition, the posterior area is the smallest because the posterior wall and labrum cover most of the head in extension and the attachment of the joint capsule is 2 to 3 cm proximal to the intertrochanteric crest, thus more proximal than on the anterior sur-face.53 If the arthroscope cannot be brought in this part of the joint without traction, placement of a postero-lateral portal appears to be dangerous without traction. The greater trochanter blocks the view of the posterolateral parts of the femoral neck. Thus, if a portal was placed without traction, the starting point on the skin would be too far posteromedial, bringing the sciatic nerve at risk for direct injury. In these circumstances, we therefore recommend inspecting the posterior area during the traction part of the procedure. Under traction, the trochanter is pulled distally, and the arthroscope introduced via the lateral or an-terolateral portal can slide over the posterolateral labrum to the posterior perilabral sulcus. Here, at least partial inspection of the posterior area of the peripheral compartment can be performed.
By slowly withdrawing the scope to the anterior surface of the neck, the diagnostic round trip of the peripheral part of the hip is finished.
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