Case Study. Hip Dysplasia treated by Shelf Acetabuloplasty

darthroplasty

A 6 month old Belgian Shepherd female dog with severe pain and disability caused by hip dysplasia was treated surgically with an acetabular augmentation procedure- DARthroplasty

In human medicine, the augmentation of the femoral head support by an extracapsular bone graft has been used for a very long time in the treatment of hip dysplasia. It was first described by König in 1891 and was the principal method of acetabular reconstruction during the first half of the 20 th century (1). Several techniques using this principle have been used. The main difference being the method used to stabilize the graft. This group of techniques are generally known by the term Shelf Acetabuloplasty, in the sense that the bone graft works as an extension of the true acetabulum. In recent decades the early diagnosis of the disease in humans permitting the correction by harnesses and by rotational osteotomies conferring hyaline cartilage coverage to the femoral head have reduced the number of shelf operations. Nevertheless, it is present in the armamentarium of many surgeons, being used mainly in late presentation cases (late childhood, adolescents and young adults) (1,2, 3,4,5). It remains as one of the few alternatives in complex late presentation cases (1), as a rescue technique should the rotational osteotomies fail to correct the deficient coverage (6) and as probably one of the best options for severe late onset Legg-Calvé-Perthes disease (7,8,9,10,11,12,13). In recent years it has been performed using minimally invasive methods (14).

In 1998 Barclay Slocum and Theresa Devine Slocum published the description and results of a shelf surgical technique for dogs that was named DARthroplasty (15). The name signifies dorsal acetabular rim plasty. More than 300 hips were operated in their 6 year experience with the technique before publication (15). The technique is indicated , according to these authors, for dysplastic hips too far advanced (in the disease process) for triple pelvic osteotomy but not yet candidates for end-stage salvage procedures (15).

Since this publication very little has been written about the DARthroplasty. The data was never collected to clarify it's definitive place in Veterinary Surgery.

CASE STUDY:
A six and a half month old Belgian Shepherd female dog was referred to the surgical center due to severe disability in both posterior limbs. She weighed 15 kg at this time. The owner of the dog described difficulties in lying down and getting up from that position, frequent crying when changing body position , difficulties with stair climbing and lameness.

Visual observation revealed deformation of the croup region with laterally protruding greater trochanters. Orthopedic examination revealed severe pain on passive extension and on abduction with concurrent external rotation of both coxofemoral joints. There was a positive trochanteric compression test bilaterally, confirming that the femoral heads were on a permanently subluxated position.

The x-ray image on figure 1 documents the bilateral subluxation compatible with the diagnosis of hip dysplasia. A one stage bilateral DARthroplasty was executed to address the dog's symptoms.

fig1 

Surgical Technique:
The dog was premedicated with Tramadol and Acepromazine. General anesthesia was induced with Propofol and Diazepam and maintained with Isofluorane. An epidural anesthesia was administered using a mixture of Lidocaine, Bupivacaine and Morphine.

A caudal approach to the hip joint was performed . The muscles were elevated from the hip capsule and from the dorsal acetabulum as described by Slocum and Slocum(15) . A 2,5 millimeter Steinman pin was hammered onto the ilium, dorsal to the cranial end of the acetabular rim and bent cranially to retract the gluteal muscles and create a stable space for the technique. A groove was created by removing the lateral cortex of the pelvis ( to the level of bleeding spongiosa) with a straight 4 millimeter Lexer gouge from the caudal to the cranial end of the acetabulum just dorsal to the capsular insertion. A second incision was performed as described by Slocum (15) to expose the entire wing of the ilium and collect, with a curved 10 mm Lexer gouge, as many cancellous and corticocancellous bone strips as possible without interfering with the iliac bone structural function. The length of the strips was estimated from x-ray images and by measuring directly over the palpable femoral head. The first strip was inserted over the capsule, parallel to the created cortical groove, and under the tendon of the deep gluteal muscle cranially, and under the tendon of the internal obturator caudally, constituting the most lateral part of the first layer of the augmentation. Additional strips were inserted parallel and medially to the first, until the last strip covers the groove on the dorsal acetabulum, making a continuous first layer. A second layer of strips was inserted parallel to the first and manually compressed over the first layer making the graft as thick as possible. Sutures were not used to stabilize the graft. The graft was maintained in position by the referred tendons and by limiting dissection to the space estimated to be necessary for the graft.

Postoperative radiographs were obtained immediately after the procedure (fig. 2) and 5 months later (fig. 3) in the full hip extended with internal rotation view. At this time the dog was 11 months old and weighed 24 Kg. A Computed Tomography Scan was performed 1 year after the surgery (figs. 4, 5 and 6 ) in moderate hip extension .

fig2 

fig3

fig4

fig5

fig6

At 5 months post-operatively the dog was fully functional in all activities including running and jumping. The range of hip motion was normal in flexion and extension . Abduction was limited by the graft, causing no detectable impairment on locomotion. Muscle mass was considered normal. No pain was detected on extending the hips. The results of these observations remain unchanged 1 year after the surgery.

frog view 

34 months

Images 34 months after surgery. The functional observations remain unchanged from the last evaluation.

DISCUSSION:
The current knowledge in Veterinary Medicine cannot accurately define the indications, effectiveness and postsurgical prognosis of the DARthroplasty or other shelf acetabuloplasties. Referring to the universe of veterinary medical publications only Slocum's description of technique and results are available to date. In their series of cases, none of the patients that have undergone DARthroplasty have demonstrated painful signs that would suggest the need for a total hip replacement (15).

The Shelf Acetabuloplasty techniques deserve to be thoroughly investigated as a surgical option for the treatment of canine hip dysplasia. Collection of objective data from the largest possible series of cases using a reproducible surgical technique would be a rational goal.

References

  1. Staheli LT, Chew DE. Slotted acetabular augmentation in childhood and adolescenceJ Pediatr Orthop. 1992 Sep-Oct;12(5):569-80.
  2. Fawzy E, Mandellos G, De Steiger R, et al. Is there a place for shelf acetabuloplasty in the management of adult acetabular dysplasia? A survivorship study. J Bone Joint Surg [Br] 2005; 87-B:1197-202.

  3. Summers BN, Turner A, Wynn-Jones CH. The shelf operation in the management of late presentation of congenital hip dysplasia. J Bone Joint Surg [Br] 1988;70-B: 63-8.

  4. Courtois B, LeSaout J, Lefevre C, et al. The shelf operation for painful acetabular dysplasia in adults: a propos of continuous series of 230 cases. Int Orthop 1987;11: 5-11 (in French).

  5. Hirose S, Otsuka H, Morishima T, et al. Long-term outcomes of shelf acetabuloplasty for developmental dysplasia of the hip in adults: a minimum 20-year follow-up study. J Orthop Sci (2011) 16:698–703

  6. Su Y, Wang M, Chang W. Slotted Acetabular Augmentation in the Treatment of Painful Residual Dysplastic Hips in Adolescents and Young Adults. J Formos Med Assoc | 2008 • Vol 107 • No 9: 720-727

  7. Kruse RW, Guille JT, Bowen Jr. Shelf arthroplasty in patients who have had Legg-Calvé Perthes disease: a study of long-term results. J Bone Joint Surg [Am] 1991;73-A:1338-47.

  8. Wright D, Perry D, Daniel C, et al. Shelf acetabuloplasty for Perthes disease in patients older than eight years of age: an observational cohort study. Journal of Pediatric Orthopaedics B 2013; vol22 issue 2: 96-100

  9. Domzalski M, Glutting J, Bowen R, et al. Lateral Acetabular Growth Stimulation Following a Labral Support Procedure in Legg-Calvé-Perthes Disease. J Bone Joint Surg Am, 2006 Jul 01;88(7):1458-1466

  10. Daly K, Bruce C, Catterall A. Lateral shelf acetabuloplasty in Perthes’ disease - A review at the end of growth. J Bone Joint Surg [Br] 1999;81-B:380-4.

  11. Osman M, Martin D, Sherlock D. Outcome of late-onset Perthes’ disease using four different treatment modalities. J Child Orthop (2009) 3:235–242

  12. Oh C, Rodriguez A, Guille JT, et al. Labral Support Shelf Arthroplasty for the Early Stages of Severe Legg-Calvé Perthes Disease. Am J Orthop. 2010;39(1):26-29.

  13. Van Der Geest I, Kooijman M, Spruit M, et al. Shelf Acetabuloplasty for Perthe's Disease: 12-Year Follow up. Acta Orthopædica Belgica, Vol. 67 - 2 – 2001

  14. Chiron P, Laffosse JM, Bonnevialle N. Shelf arthroplasty by minimal invasive surgery: technique and results of 76 cases. Hip International / Vol. 17 no. 2 (suppl 5), 2007 / pp. S72-S82

  15. Slocum B, Slocum T. D. DARthroplasty. In: Bojrab, M. J., ed. Current Techniques in Small Animal Surgery, 4th Ed. Baltimore: Williams & Wilkins 1998: 1168 - 1170 





 

 

 

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