Conservative Hip Surgery Case Title: Surgical Hip Dislocation as First Step for Revision of Instability from Arthroscopy

Demographics

1.  

   Age: 33 years Sex: female BMI: 24

    

2. Relevant Past Medical History

    

   Principal pathologies: Residual anterolateral acetabular dysplasia and high femoral anteversion. Anterolateral loss of the joint cartilage

   Previous surgical procedures: Arthroscopic labrum resection

   Medication: Pain medication after arthroscopy

   History of presenting complaint: Occasional pain since many years in the left hip more frequent than right. A slight increase over time and during sports (synchronized swimming, skiing, general fitness). Increased pain after arthroscopy without improvement over a period of five months. Progredient limitation during ADL

    

3. Clinical Examination

    

   Symptoms: Constant pain during ADL, aggravated when walking more than two blocks or sitting longer than 60 min. Feeling of instability when walking with an externally rotated foot

   Range of motion: Normal ROM but painful toward full flexion and flexion/internal rotation

   Specific tests: Positive impingement test. Positive apprehension in forced extension/exter-nal rotation

   Main disability: Feeling of instability

   Scoring if available: OHS 46 (of 48), EQ5D index 0.91, COMI 0.45, quality sat very satisfied, GOT operation helped

   Neurovascular evaluation: Normal neurovascular status

    

4. Preoperative Radiological Assessment/Imaging (Figs. 1.12, 1.13, and 1.14)

    

    

    

   Fig. 1.12 AP pelvic radiography: right LCE angle 24°, left LCE 18°, roof inclination 20°

    

    

    

    

   Fig. 1.13 Lateral view: high femoral anteversion (in MRI 36°)

    

    

   a

   b

    

    

    

   Fig. 1.14 (a) MRI showing the anterior migration of the femoral head and (b) intraoperative photograph demonstrating the severely altered acetabular cartilage and the absent labrum (arrows)

    

   Other: Drawing of the surgical dislocation approach.

    

5. Preoperative Planning

    

   Diagnosis: Multifactorial hip dysplasia (minor residual acetabular dysplasia, high femoral anteversion, joint instability after arthroscopy, and labrum resection) (Figs. 1.12, 1.13, and 1.14).

   Possible treatment options: Intertrochanteric varus + derotation osteotomy. Surgical dislocation ± labrum reconstruction + derotation. Surgical dislocation ± labrum reconstruction, derotation, and periacetabular osteotomy.

   Chosen treatment method: Surgical dislocation + labrum reconstruction + subtrochanteric derotation + periacetabular osteotomy.

   Selection of implants if applicable and rational: Seven-hole straight narrow plate for 4.5 mm screws for derotation osteotomy. Metal anchors for labrum reconstruction. 5 × 3.5 mm screws, length 60–80 mm, for trochanter and acetabular fragment fixation.

   Expected difficulties: Scarring around the joint capsule from the previous arthroscopy. Missing labrum and potential cartilage lesions. The decision whether the joint is sufficiently stabilized after the different reconstruction steps.

   Strategies to overcome difficulties: The first aspect can only be overcome by careful and slowly advancing dissection. For the second aspect, the surgical dislocation approach offers the necessary information, and the presented case may show how it is processed: A first test revealed no pop signs indicating that there is no sufficient labral sealing and no intrinsic joint stability. It was clear that labrum reconstruction would not create sufficient stability, but it was thought to improve lubrication and joint physiology. After labrum reconstruction, retesting showed the rees-tablished pop phenomenon. Further testing the stability demonstrated (a) that the role of the high femoral anteversion could be reduced by 30° derotation and (b) that no additional varus correction would be necessary. Therefore, the derotation was performed at the subtrochanteric level where the execution is easier and the hardware less prominent. The stability was tested again, and the palpating finger revealed some bouncy stability with extreme external rotation in full extension. This impression together with the borderline acetabular coverage and the cartilage damage near the rim led to the definitive indication for a periacetabular osteotomy. The osteotomy was performed in the same anesthesia with the execution of the first ischial cut through the femoral approach.

   Templating: Templating on transparent paper

   or with a computer program may be useful before an intertrochanteric osteotomy is executed but is not suitable for the surgical steps described here.

    

6. Surgical Note

    

   Patient’s position: The patient is kept in the lateral decubitus position. A holder is placed against the lower lumbar spine and the symphysis. Skin preparation and draping is performed for a free leg. In this case, draping should allow eventual subtrochanteric derotation as well as cushion periacetabular osteotomy (PAO) without redraping. The leg is positioned on a plastic foam bolster which is excavated on the undersurface to include the opposite leg. The primary incision is placed over the greater trochanter with a straight distal extension of about 10 cm from the trochanteric tip; the proximal extension is slightly curved toward the posterosuperior iliac spine. The leg to be operated should allow flexion/external rotation of the hip to bring the leg over the front of the table and place it into a sterile bag.

   Type of anesthesia: General or conductive anesthesia. General anesthesia when an intraoperative change of decubitus is planned.

   Surgical approach: Surgical hip dislocation is an anterior dislocation through a trochanteric flip osteotomy (1). All external rotators remain attached to the greater trochanter by which the blood supply to the head coming from the deep branch of the medial femoral circumflex artery and the anastomoses with the superior and inferior gluteal vessels is secured. The technique allows dislocating the head up to 10–12 cm from the acetabulum giving nearly 360° view to the head and 360° to the acetabulum. The approach can be extended distally to expose the entire femur (2). It is the workhorse for intra-articular surgery, e.g., labral and rim surgery, as well as for osteochondroplasty of the head-neck junction. Together with an extended retinacular flap, it is a safe approach for relative neck lengthening, subcapital realignment in SCFE, femoral neck osteotomy, and osteotomy to reduce the size of the femoral head. It is useful for difficult THR and acetabular and femoral head fracture fixation. When periacetabular osteotomy is a supplementary procedure, the first ischial cut can be executed via the surgical dislocation approach, allowing visual control of the sciatic nerve during execution of this osteotomy. Finally,

   intra-articular observations allowed to formulate and validate the impingement concept (3).

   Main steps: After skin incision, the fascia lata is displayed over the anterior border of the gluteus maximus muscle; identification of perforans vessels helps to identify this level. The more proximal the fascia incision is extended, the easier becomes the mobilization and posterior retraction of the gluteus maximus. With an internal rotation of the leg, the posterior border of the gluteus medius is identified. The next step is the trochanteric osteotomy. It is first marked with the cautery knife from the posterosuperior tip of the trochanter extending distally to the posterior border of the vastus lateralis ridge before the osteotomy is executed using an oscillating saw. The fragment includes the insertion of the gluteus medius proximally, the origin of the vastus lateralis distally, and the long tendon of the gluteus minimus anteriorly; it has a maximal thickness of about 1.5 cm. At its proximal end, the osteotomy exits anteriorly to the most posterior insertion of the gluteus medius muscle; this helps to keep the majority of the piriformis tendon attached to the stable part of the trochanter. The trochanter fragment is mobilized anteriorly after releasing the vastus lateralis along its posterior border to about the middle of the tendon of the gluteus maximus muscle. The most posterior fibers of the gluteus medius are also released together with eventually remaining fibers of the piriformis tendon. With increasing flexion and external rotation of the leg, the vastus lateralis and intermedius are released from the lateral and anterior aspect of the proximal femur. Proximally, the tendon of the piriformis becomes visible in its fatty tissue layer after careful anterior retraction of the posterior border of the gluteus medius. The inferior border of the gluteus minimus is dissected and retracted from piriformis tendon and capsule, creating an interval which is safe for the blood supply to the femoral head. Care has to be taken to avoid injury to the sciatic nerve. The entire flap is then gradually retracted anteriorly and superiorly. Further flexion and external rotation of the leg facilitate a final visualization of the anterior, superior, and posterosuperior capsule. The capsular incision is Z shaped (right side) and is started anteriorly along the femoral neck; this avoids injury to

    

   the retinacular vessels. Elevation of the anterior flap is possible with an incision along the neck attachment and directed toward the anteroinferior border of the acetabulum. The first incision is then extended toward the acetabular rim, where it is turned posteriorly parallel to the labrum reaching the retracted piriformis tendon. Care must be taken not to injure the labrum. For dislocation the leg is flexed, externally rotated, and brought over the front of the table, where it is placed in a sterile bag. With a hook placed around the neck, the head can be subluxated allowing already some inspection of the acetabulum. For complete dislocation the round ligament is incised; the stump remaining on the head may be resected. Three retractors are used for optimal inspection of the acetabulum, while visualization of the femoral head is possible with lowering the knee and rotation of the leg. The retinaculum covering the terminal vessel branches to the head is visible on the posterosuperior circumference of the neck. During the inspection of the joint, the exposed cartilage is constantly irrigated to prevent drying. At the end of the procedure, the femoral head is easily reduced with axial pull on the slightly flexed femur and with the knee flexed. The capsule is readapted but not tightly sutured. For refixation of the greater trochanter two

   3.5 mm, in large bones 4.5 mm cortical screws of

   60–70 mm length are used. The wound is closed with running sutures layer by layer. Suction drainage is not routinely used (Figs. 1.15 and 1.16).

   Reconstruction techniques: A surgical hip dislocation is an approach and not a procedure per se. It is, however, the door for a multitude of reconstruction procedures, some of which are demonstrated with this example. In a case where advancement of the trochanter is not planned as in this case, the osteotomy can be executed in a stepwise fashion which increases the intrinsic stability of the fixation. It may allow to reduce restrictions and start muscle rehabilitation and weight bearing earlier.

    

7. Intraoperative Challenges

    

   Challenges and solutions: Very muscular hips may need a proximal and distal extension of the incision of the fascial lata followed by a release of

   gluteus maximus tendon to ease dislocation of the hip. In hips with fixed external rotation, the hip cannot be internally rotated sufficiently to perform the trochanteric osteotomy with the oscillating saw. In this situation, the osteotomy may be performed with an osteome from distal to proximal. In hips with protrusion but also in severe slips, the stable portion of the trochanter may impinge against the posterior acetabular wall, and dislocation may only be possible after trimming of the stable trochanter down to the level of the femoral neck. When soft tissue tension impedes the substantial distal advancement of the trochanter, the release of the long tendon of the gluteus minimus muscle along the anterior border of the trochanteric fragment is an effective measure.

   Unanticipated problems and solution: Scarring from previous surgery or trauma may create difficulties to dissect the different structures. There is no special solution to offer but very careful dissection; advancing with small steps is the best strategy to succeed. Careful dissection and topographic identification of the sciatic nerve can be a very helpful step to avoid injury during further execution of the surgery, especially when preexisting scarring makes the procedure demanding. The best level to start this dissection is near the quadratus femoris muscle. After former intra-articular surgery, the joint capsule may be scarred near the distal circumference limiting mobilization of the femoral head. Presentation of head and acetabulum can be improved by step-by-step incision of the inferior capsule, eventually including the psoas tendon. The fracturing of the trochanteric fragment is a rare complication, and the result of insufficient thickness severely reduced mechanical quality or the result of levering the fragment before complete separation. The solution may be atypical screw fixation or wire cerclages, eventually combined with increased protection adding a plaster. Delayed or nonunion of the greater trochanter is an occasional problem in the early postoperative phase and is mainly initiated by overload and/or reduced bone quality. Refixation is performed with screw exchange. Local pain over the screw heads is a common problem in the later phase of rehabilitation. Screw removal can take place after six months postoperatively.

    

   Thorough description of decision making, including the reason for the final decision: Visual and manual testing of the joint stability is the last step before closing the capsule. Warning signs may be anticipated and allow to get the necessary patient agreement for further surgical steps as demonstrated in the presented case. Occasionally joint instability is ascertained as a surprise, e.g., after rigorous trimming of the acetabular rim. Repeated testing before capsular suture should then lead to clarification: (1) about an audible pop indicating a good sealing function of the labrum which adds to joint stability, (2) about the direction and force of movements leading to subluxation/dislocation, and (3) about a possible fulcrum levering the femoral head out of the socket. When the head dislocates without audible sealing, labrum reconstruction may be executed. Using the round ligament, it may be executed even without a formal agreement of the patient. This also applies when only the posterosuperior aspect of the stable part of the greater trochanter serves as a fulcrum and has to be resected. Any other additional procedures like relative lengthening of the neck, derotation/angulation osteotomy, and periacetabular osteotomy have to be deferred until permission of the patient has been obtained.

8. Postoperative Radiographs

    

    

    

   Fig. 1.15 Postoperative AP pelvic radiograph showing the different procedures undertaken by the surgical hip dislocation approach. All procedures were necessary step by step to finally guarantee joint stability without interfering with impingement-free motion: (1) reconstruction of the labrum fixed with metal anchors, (2) subtrochanteric derotation 30° to re-center the head into the socket, and

   (3) periacetabular osteotomy to overcome the rate of instability related to residual dysplasia + peripheral cartilage damage

    

   a

   b

    

    

    

   Fig. 1.16 1-year result with completely consolidated osteotomies in (a) the AP pelvic and (b) cross-table radiographs

    

9. Postoperative Management

    

   Chemoprophylaxis and anticoagulant treatment period: Routine antibiosis is given for 24 h. Prophylaxis for DVT is maintained until full weight bearing.

   Gait/limb loading until full loading: Patients with a surgical hip dislocation start ambulation on elbow crutches at the first or second postoperative day, depending on the complexity of additional procedures. Standard loading is 15 kp, to be controlled on a bathroom balance. The first clinical and radiographic follow-up control is normally fixed for six weeks after surgery; when a stepwise trochanteric osteotomy was performed, the first control date can be advanced to four weeks after surgery. At this time, rehabilitation measures for abductor training and joint mobility are started. When bridging callus becomes visible at the osteotomies, weight bearing can be gradually increased. Full and unrestricted weight bearing without crutches may be allowed after 10–12 weeks provided the force of the gluteus medius muscle has reached an M5 again.

    

10. Follow-Up and Complications

     

    In our patient, no complication occurred during follow-up time; however, trochanteric pain radiating mainly to the lateral aspect of the knee persisted as did inguinal pain. Metal removal more than one year after surgery led to a marked improvement of her symptoms.

     

11. Discussion

     

    Advantages of the applied method: Surgical hip dislocation is a versatile approach to the hip without the risk of avascular necrosis. It allows a 360° observation of the acetabulum and nearly 360° control of the femoral head. Besides surgery on the acetabular rim complex, joint cartilage, and head-neck junction, it is the workhorse for a number of new osteotomies only possible with this approach. Furthermore, it allows control-ing impact and accuracy of extra-articular osteotomies, e.g., deroration.

    Disadvantages of the method: Surgical hip dislocation as described here has no real disadvantages. From beginners it may be called an elaborate technique; however, it is not demanding in the proper sense. Failure of the trochanteric fixation is often mentioned as a major problem but has decreased with ongoing experience. Overall it is rated as a safe procedure with low morbidity [23]. Alternative evidence-based techniques for the case: Without the high pathological anteversion of the femur, straightforward periacetabular osteotomy could have been discussed as an alternative but would have made intra-articular surgery rather difficult. With the obvious indication for additional derotation, the best concept was to start on the femoral side. Doing so, additional surgical dislocation allowed optimal execution of intra-articular surgery and efficiency of the femo-

    ral procedures [22].

    Why is the chosen technique better for this case? See above [23].

    Indications and contraindications for your technique: The indication is given when intra-articular control and surgery are not possible with arthroscopy and vice versa.

    Learning curve and how to manage complications: Under professional supervision, there is a rapid learning curve. For management of complications, see above.

    Level of evidence concerning the superiority of this method against others: 15 years after the first publication [21], there is ongoing literature describing the unique benefit of this approach [24, 25].