Birm
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mingham
necrosis
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Birmingham mid-head resection arthroplasty of hip for avascular
necrosis of femoral head e A minimum follow up of 2 years
...
BMHR arthroplasty for early stage AVN of the femoral
head. We offered mid-head resection arthroplasty to all
the patients ...
Napkin ring is placed at HNJ after chamfering of head
was done (Fig. 5) and apple core reamer was used to
ream the head an...
Radiographic analysis was performed independently by
two observers (VCB and SKR). Points noted were lucent
lines, osteolys...
latest follow up, the patient is asymptomatic and there are
no radiological evidence to suggest anything amiss with
the im...
4. Mont MA, Marulanda GA, Jones LC, et al. Systematic anal-
ysis of classification systems for osteonecrosis of the femoral...
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Birmingham mid-head resection arthroplasty of hip for avascular necrosis of femoral head – A minimum follow up of 2 years

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To study the outcome of Birmingham mid-head resection (BMHR) arthroplasty of the hip in young and active patients with avascular necrosis of femoral head with gross defects.

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Birmingham mid-head resection arthroplasty of hip for avascular necrosis of femoral head – A minimum follow up of 2 years

  1. 1.                                                   Birm n                                                 mingham necrosis                                      m mid-hea of femora        ad resect al head - ion arthro - A minim      oplasty o mum follow f hip for a w up of 2 avascular years r
  2. 2. Birmingham mid-head resection arthroplasty of hip for avascular necrosis of femoral head e A minimum follow up of 2 years K.R. Sharatha,c , V.C. Boseb,* ABSTRACT Aim: To study the outcome of Birmingham mid-head resection (BMHR) arthroplasty of the hip in young and active patients with avascular necrosis of femoral head with gross defects. Materials and methods: Study was conducted between Oct 2007 and Dec 2009. Twenty-three hips were operated upon in this period and data was collected for all patients. Radiographs were obtained in all subjects pre-operatively and compared to post-operative radiographs to determine migration of the components. Functional outcome was assessed in all patients using the University of California, Los Angeles (UCLA) scores. Complications, if any were recorded. Results: None of the patients were lost to follow up. None of the components migrated. All the patients remained active with mean UCLA score of 7.23 and there were no failures till our last review. Conclusion: This study shows promising early results of bone preservation and restoration of the biomechanics of normal hip in young and active patients with gross defects of the femoral head using BMHR procedure. Copyright © 2012, Indraprastha Medical Corporation Ltd. All rights reserved. Keywords: BMHR, AVN, Joint replacement Modern hip resurfacing is an attractive alternative to total hip replacement for young and active patients.1 Young and active patients have always been a challenge for hip arthroplasty surgeons as the hip is subjected to increased demands and the implants have to stay functional for a long time. In patients who are unsuitable for resurfacing due to poor bone quality in the femoral head, and yet conservative arthro- plasty is desirable, Birmingham mid-head resection (BMHR) arthroplasty would be an alternative. Avascular necrosis (AVN) of femoral head is one such condition which affects the younger population. Resurfacing arthroplasty in the early stages of AVN has fared poorly in terms of longevity.1,2 While in other patients in the late stages of AVN, femoral heads may not be suitable for resurfacing due to the presence of sub-chondral cysts more than 1 cm and/or gross destruc- tion. BMHR arthroplasty involves resection of poor quality bone of femoral head proximal to the described resection level for resurfacing and retains the distal part of the femoral head, which participates in load transfer from the stem.3 In this paper we describe our experience with mid-head resec- tion device and present our results with a minimum follow up of 2 years. MATERIALS AND METHODS Between Oct 2007 and Dec 2009, we collected data on twenty consecutive patients (23 hips) who underwent a Asst Prof, MS Ramiah Medical College, Bangalore, b Senior Consultant Orthopedic Surgeon, Apollo Speciality Hospital, Chennai 600035, Tamil Nadu, India. * Corresponding author. email: bose5vijay@hotmail.com Received: 7.9.2012; Accepted: 5.10.2012; Available online 13.10.2012 c Study performed when attending a fellowship in joint replacement at Apollo Hospitals, Chennai. Copyright Ó 2012, Indraprastha Medical Corporation Ltd. All rights reserved. http://dx.doi.org/10.1016/j.apme.2012.10.001 Apollo Medicine 2012 December Volume 9, Number 4; pp. 297e302 Original Article
  3. 3. BMHR arthroplasty for early stage AVN of the femoral head. We offered mid-head resection arthroplasty to all the patients who attended our clinic with MRI diagnosis of AVN of the femoral head with large cysts or to those who had collapsed femoral heads (Stage 4 modified Ficat & Arlet staging).4 Among the 23 hips, four hips that were posted for resurfacing arthroplasty of the femoral head, we switched to perform mid-head resection arthroplasty on the table due to the small size of the femoral heads (<46 mm).5 In two other hips, we found large sub-chondral cysts with sclerotic non-viable bone. Patients who were old (>60 years) with sedentary lifestyles, and patients with a history of renal failure or renal compromise5 were excluded from the study. All patients in whom the femoral head was in the early pre-collapse stage were managed conservatively, but the subset of these patients who were severely symptomatic with pain and stiffness underwent either core decompression or BMHR arthroplasty. The approval of local ethical committee was obtained and clinical and radiological data, along with outcome scores were collected. OPERATIVE TECHNIQUE In the lateral position and general anesthesia the hip was exposed through the posterior approach. Gluteus maximus tendon was released routinely. Ascending branch of medial circumflex was sacrificed and short external rotators were incised without disturbing the joint capsule. Capsule was then incised close to acetabulum from 12’ O clock to 6’ O clock position to preserve retinacular vessels. Lower limb was internally rotated up to 90 to visualize the anterior capsule. Anterior capsule was then incised close to the labrum. Circumferentially the hip joint capsule was incised away from the femoral neck preserving the soft tissue cover over the femoral neck. This neck capsule approach has been described previously.2 After opening the hip by neck capsule preserving approach, initial step would be to determine the minimum size of femoral component the femur would accommodate (Fig. 4). Accordingly the acetabulum size also determined. But reaming of acetabulum will be done independent of femoral preparation. McMinn jig was positioned to pin placed in lateral cortex and head preparation was carried out. There should be intact head neck junction (HNJ) for resurfacing devices. In case the proportion of defects in head is more than intact head, BMHR will be the procedure of choice. Since instrumentation is same for both, decision of switch- ing to BMHR from BHR can be carried out on the table. Fig. 1 Method used for calculation of stem shaft angle and cup inclination. Fig. 2 Ratio of base of stem diameter and neck diameter. Fig. 3 Conical reaming using conical reamer. 298 Apollo Medicine 2012 December; Vol. 9, No. 4 Sharath and Bose
  4. 4. Napkin ring is placed at HNJ after chamfering of head was done (Fig. 5) and apple core reamer was used to ream the head and decision of implanting BMHR was taken. Proper positioning of ring is very important for leg length equality. Uppermost part of head was removed over the ring. Trial implantation was done at this stage for leg length assessment. Cone reamer for stem was used to ream the neck (Figs. 3 and 7). Conical uncemented BMHR stem was then placed over reamed neck. Modular head with 12/14 taper was then placed over stem (Fig. 6) matching to the size of implanted acetabular cup. Procedure is similar to the one described by McMinn.6 Meticulous capsule-to-capsule closure was performed with No-2 ethibond sutures. Post-operatively drain was not used routinely. All patients received three doses of prophylactic antibi- otic (1 g Cefazolin) perioperatively. Thromboprophylaxis was in the form of Enoxaparin after 8 h of surgery until discharge. Thromboembolus deterrent (TED) stockings and 75 mg aspirin once daily for a duration of 4 weeks was prescribed at the time of discharge.7 All the patients were mobilized full weight bearing on the first post-opera- tive day. Supervised physiotherapy was commenced and continued throughout the inpatient period. No restrictions were imposed otherwise except for the use of abduction pillow when in lateral position for 4 weeks. Post-operatively, the patients were followed up at 6 weeks, 6 months, 1-year, and then at 2-year intervals. For the purposes of this study pre-operative functional hip scores (UCLA hip score) were collected and repeated at the latest follow up. The antero-posterior (AP) view of the pelvis was obtained at each follow up.8 For pre and post-operative hip scores and activity scores, descriptive statistics were calculated and statistical significance analyzed using an unpaired Students t-test. Fig. 5 Napkin ring. Fig. 6 Implanted BMHR. Fig. 7 Conical reamer and stem. Fig. 4 Measuring head size. BMHR arthroplasty of hip for avascular necrosis of femoral head Original Article 299
  5. 5. Radiographic analysis was performed independently by two observers (VCB and SKR). Points noted were lucent lines, osteolysis, spot welding, component loosening, and migration. The inter teardrop line was used as the reference for cup inclination (Fig. 1). The distance between the ischial tuberosity and a fixed point on the lesser trochanter was used to measure leg length and compared to the contra- lateral side. Angle between lines joining mid-diaphyseal line and mid-line of implant stem was compared post-oper- atively and at latest follow up. RESULTS The mean follow up was 23.57 months. Twenty patients were diagnosed to have idiopathic avascular necrosis, of which 2 were steroid induced and one post-traumatic. Mean age of patients was 38.7 years with youngest patient being 19 years and oldest 56 years (Table 1). All patients were under the care of a senior orthopedic surgeon (VCB) who performed all the procedures. Ten patients had bilateral avascular necrosis. Out of these ten, three of them underwent bilateral BMHR, another three underwent BHR on one side and BMHR on the oppo- site side, two of them underwent THR on one side and BMHR on the opposite side, and the remaining two patients underwent BMHR on one side and conservative treatment on the opposite hip. There were no major post-operative complications like DVT or infection, either superficial or deep. Two patients required blood transfusion and one patient had transient urinary symptoms that settled with antibiotics for a period of 1 week. There was significant improvement in UCLA scores post-operatively (Table 2). The mean inclination of the acetabular component was 46.2 as measured on the latest AP pelvis radiograph and the mean stem shaft angle was 132.8 (Table 3). There were no radiolucencies or evidence of osteolysis around the acetabular or the femoral components. Femoral compo- nent-femoral shaft angle was valgus in seventeen patients, neutral in six patients compared to original.9 None of the components were in varus position. Out of 23 hips, 2 hips had V1 stem and the rest got VST stems. Mean combined abductionevalgus angle (we proposed in our previous paper) was 184.53 . DISCUSSION Birmingham mid-head resection technique is relatively new and promising for those hips where resurfacing is not possible yet conservative arthroplasty is desirable. Unce- mented HA coated proximal stem with porous coated, grit blasted fluted distal stem helps in good osteo-integration and rules out the possibility of cement related loosening and augurs well with recent trends of uncemented arthro- plasty. Birmingham mid-head resection is more versatile in equalizing the limb lengths10 and valgus or neutral orien- tation of femoral components. Although neck narrowing has been observed in 2 cases it is unlikely to be an indicator of neck fracture. Neck fracture is a phenomenon of short term failure and that which is not seen for first 2 years is highly unlikely to occur later as explained by Takamura et al.11 There is association of neck narrowing with valgus orientation of native neck shaft angle (although not statistically signifi- cant). Position of femoral stem with respect to neck is key to survival of prosthesis. Tip of stem should never touch any of the cortices in both AP and lateral plane radiographs. We have measured implant tip to lateral cortex width in post-operative and immediate follow up X-rays. There is no significant movement of stem either due to subsidence or varus collapse. For neck thinning we measured width of implant (femoral component base) and width of neck (at implant neck) and ratio of the values were calculated (Fig. 2). Measurement of ratios helps us to avoid issues of magnification, that are common with digital X-rays. Ratios at immediate post-operative and latest follow up have not changed with respect to statistically significant values. There was no narrowing or any evidence of stress shielding of the femoral neck. In our study no patients had any issues with regard to metallosis or adverse local tissue reaction (ALTR). No patient had any local fluid or solid mass or allergic reac- tion.12 Mean acetabular cup inclination was 43.18 . One patient had acetabular cup inclination of 55.85 . At the Table 1 Clinical details of 20 patients (23 hips). Age (in years) 38.78 (19e57) Height (in cm) 164 (158e183) Weight (in kg) 79.7 (57e99) Male:female 22:1 BMI 27.79 (21.71e36.58) Table 2 Details of University of California, Los Angeles score (UCLA). Pre-operative Post-operative p-Value UCLA (n ¼ 20)a 4.2 7.9 0.0000012 UCLA (n ¼ 10)b 3.8 7.5 0.000023 a There were total 20 patients who were administered UCLA score. b Ten patients had bilateral involvement and other side hip was operated in 8 patients (3 BHR, 2 THR, 3 BMHR), 2 patients had conservative treatment. UCLA after exclusion of those 10 patients. 300 Apollo Medicine 2012 December; Vol. 9, No. 4 Sharath and Bose
  6. 6. latest follow up, the patient is asymptomatic and there are no radiological evidence to suggest anything amiss with the implants. ROM was improved significantly in all patients, but improvement was more in patients with more pre-operative range. There were no radiological signs of repetitive impingement of neck. None of the patients had a post-oper- ative dislocation at the latest follow up. Gait was normal for all but one patient, who had had clinical shortening of 1 cm post-operatively. He was advised shoe modification. No other patients had any leg length discrepancy. One patient complained of groin pain anteriorly which was aggravated by activity. It was treated with short term analgesics. Pain intensity reduced but was not relieved completely. The average UCLA score was 7.9 post-operatively when compared to a pre-operative average score of 4.2, and this was highly significant (Table 2). This satisfaction is most likely as a result of high post-operative activity, good abductor strength and good pain relief. Migration of well fixed femoral component in resurfaced patients with osteonecrosis is a known phenomenon due to continued process of head destruction and enlargement of existing small cysts in sub-chondral area. In the BMHR procedure, we remove all the necrotic head while preserving the vascularity of the retained neck by the use of modified neck capsule preserving approach.13 As a result of both of above said reasons, we can expect good osteo- integration of femoral component. The present study had some limitations. We used revi- sion of the prosthesis as end point, but it is possible that there were some cases in which hip was symptomatic and was failing but had not yet reached revision. This is a common limitation of studies that use revision as end point.14 But since we are considering a small number of patients with short term study we could get to their symp- toms or other problems individually during their follow up. We have not considered metal ion studies either pre- operatively or post-operatively to screen our patients, and post-operative MRI/ultrasonography to detect any asymptomatic fluid collection or pseudotumor formation. We could not perform these screening procedures as there are no standard guidelines15e17 available for the same and cost was a limiting factor in most of our patients. Overall the results suggest that reliable and durable short term outcomes may be expected with use of uncemented COeCr monoblock acetabular cup with uncemented femoral mid-head resection component. However proper patient selection and following proper surgical techniques are sine qua non for the initial behavior of metal compo- nents. Further long term studies will be useful in ascertain- ing the eventuality of mid-head resection arthroplasty, in comparison to conventional total hip arthroplasty for usage in young and active individuals with gross destruction of femoral head. CONFLICTS OF INTEREST All authors have none to declare. ACKNOWLEDGMENTS Mr Jahir Abbas helped us with data collection and Dr Bis- wajit Dutta Baruah assisted with data assimilation and statistical analysis. REFERENCES 1. Adili A, Trousdale RT. Femoral head resurfacing for the treat- ment of osteonecrosis in the young patient. Clin Orthop Relat Res; 2003:93. 2. Bose VC, Baruah BD. Resurfacing arthroplasty of the hip for avascular necrosis of the femoral head. J Bone Joint Surg Br. 2010;92-B:922e928. 3. McMinn DJW, Daniel Joseph, Ziaee Hena, Pradhan Chandra. Mid head resection technique for complex deformity: Euro- pean experience. Tech Orthop. 2010;25:1. Table 3 Details of radiological parameters (mean, range). Pre-operative Post-operative p-Value Neck shaft angle 137.48 (129.2e145.3) 145.69 (134.2e156) 0.00032 Acetabular inclination 45.23 (39.01e52.45) 43.18 (37.9e50.85) 0.19 Immediate post-operative Latest follow up p-Value Acetabular inclination 43.18 (37.9e55.85) 43.05 (37.3e55.85) 0.75 Neck shaft angle 145.69 (134.2e156) 144.98 (134.8e155.87) 0.678 Neck width ratio 0.248 (0.20e0.36) 0.244 (0.20e0.34) 0.777 Tip to lateral cortex 32.01 (12.0e61.0) 32.23 (12.8e60.46) 0.29 BMHR arthroplasty of hip for avascular necrosis of femoral head Original Article 301
  7. 7. 4. Mont MA, Marulanda GA, Jones LC, et al. Systematic anal- ysis of classification systems for osteonecrosis of the femoral head. J Bone Joint Surg Am. 2006;88(suppl 3):16e26. 5. McBryde Callum W, Thievendran Kanthan, Mc Thomas Andrew, Treacy Ronan BC, Pynsent Paul B. The influence on head size and sex on the outcome of Birmingham hip resurfacing. J Bone Joint Surg Am. 2010;92:105e112. 6. McMinn DJW. Patient Positioning and Exposure. Modern Hip Resurfacing. 1st ed. Birmingham UK: London: Springer-Verlag; 2009:189e222. 7. Sandiford NA, Muirhead-Allwood S, Skinner J, Kabir C. Early results of the Birmingham mid-head resection arthro- plasty. Surg Technol Int. 2009;18:195e200. 8. Rahman Luftfur, Muirhead-Allwood Sarah K. The Birming- ham mid-head resection arthroplasty e minimum two year clinical and radiological follow-up: an independent single surgeon series. Hip Int. 2011;21(3):356e360. 9. Hayer Catherine L, Potter Hollis G, Su Edvin P. Imaging of metal-on-metal hip resurfacing. Orthop Clin North Am. 2011;42:195e205. 10. Shimmin Andrew J, Bare John V. Comparison of functional results of hip resurfacing and hip replacement: a review of literature. Orthop Clin North Am. 2011;42:143e151. 11. Takamura Karren M, Yoon James, Ebramzedeh Edward, Campbell Patricia A, Amstutz Harlan C. Incidence and signif- icance of femoral neck narrowing in the first 500 conserve plus series of hip resurfacing cases: a clinical and histologic study. Orthop Clin North Am. 2011;42:181e193. 12. Amstutz Harlan C, Le Duff Michel J, Campbell Patricia A, Wisk Lauren E, Takamura Karren M. Complications after metal-on-metal hip resurfacing arthroplasty. Orthop Clin North Am. 2011;42:207e230. 13. McMinn Derek JW, Pradhan Chandra, Ziaee Hena, Daniel Joseph. Is mid-head resection a durable conservative option in the presence of poor femoral bone quality and dis- torted anatomy? Clin Orthop Relat Res. 2011;469:1589e1597. 14. Vendittoli PA, Lavigne M, Roy A, Mottard S, Girard J, Lusignan D. Metal ion release from bearing wear and corro- sion with 28 mm and large diameter metal on metal bearing articulations. J Bone Joint Surg Br. 2011;92-B:12e19. 15. Gruen TA, Duff MJL, Wisk LE, Amstutz HC. Prevalence and clinical relevance of radiographic signs of impingement in metal-on-metal hybrid hip resurfacing. J Bone Joint Surg Am. 2011;93-A:1519e1526. 16. Davda K, Lali FV, Simpson B, Skinner JA, Hart AJ. An anal- ysis of metal ion levels in the joint fluid of symptomatic patients with metal on metal hip replacements. J Bone Joint Surg Br. 2011;93-B:738e745. 17. Daniel Joseph, Ziaee Hena, Pradhan Chandra, Pynsent Paul B, McMinn DJW. Renal clearance of cobalt in relation to use of metal-on-metal bearings in hip arthroplasty. J Bone Joint Surg Am. 2010;92:840e885. 302 Apollo Medicine 2012 December; Vol. 9, No. 4 Sharath and Bose
  8. 8. Apollohospitals:http://www.apollohospitals.com/ Twitter:https://twitter.com/HospitalsApollo Youtube:http://www.youtube.com/apollohospitalsindia Facebook:http://www.facebook.com/TheApolloHospitals Slideshare:http://www.slideshare.net/Apollo_Hospitals Linkedin:http://www.linkedin.com/company/apollo-hospitals Blog:Blog:http://www.letstalkhealth.in/

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