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SA Orthopaedic Journal

On-line version ISSN 2309-8309
Print version ISSN 1681-150X

SA orthop. j. vol.17 n.1 Centurion Feb./Mar. 2018


There were no reported major complications such as dislocations, deep infections or femoral nerve palsies in this study.

There were four patients who presented with soft tissue complications. Two of these had rectus femoris pain, one had psoas tendinitis and the other patient reported iliotibial band pain - all resolved with physiotherapy and simple analgesics, and did not require further intervention.

There were two reported cases of transient lateral femoral cutaneous nerve numbness, and four cases of clinically relevant leg length discrepancy (>1 cm difference compared to the opposite side). The leg length discrepancies were not validated on Imatri during the study.

Two patients required re-operation. One was for a greater trochanter fracture, which migrated and needed fixation. The other was for a periprosthetic fracture following a fall at six weeks. The fall resulted in femoral subsidence; however, the stem was deemed to be stable in the new position, and the hip required a longer head only.

There were six cases of thigh swelling which resolved on discontinuation of oral anti-coagulation and three cases had minor wound breakdown, which necessitated regular dressings and resolved without surgery.



A recent study published by Matta using the DAA with imaging and a fracture table showed comparable results. In his series of 437 consecutive patients they achieved an average inclination of 42° with 96% of patients in Lewennik's safe zone23 (range 35-55°) and average cup anteversion of 19° with 93% in the safe zone (range 10-25°).9

Nakata showed significantly more acetabular components were placed in 'safe zones' with the DAA (98 of 99 THA) compared to the posterior approach (87 of 96 THA).2

Other published results have also shown good results for cup positioning using the DA24-26 with a large cohort study of 1 152 patients having an average inclination of 42.1° (SD 6.6) and anteversion of 19.2 (SD7.7).10

We had similar results with 95.5% of the cups inserted in the safe zone for inclination and only one outlier for anteversion according to Lewennik's prescribed zones.

In the early part of the study, three outliers were identified with excessively abducted cups, with all having raised BMI values above 35 kg/mz. It is well documented that obesity renders accurate cup placement a challenge.27,28 When the shorter distal skin incision is used in these overweight patients, there is a tendency for the standard cup introducer to be pushed into a more vertical position, and therefore the cups are abducted in high BMI patients. Subsequently a higher offset acetabular introducer was used (Figure 11) which improved the inclination angles in these larger patients.



In the literature there are two commonly used references for safe zones for cup replacement; Lewinnek23 and McCollum and Gray.29 Both of these give a wide range of inclination for safe cup placement that does not take into account that inclination more than 45 degrees increases wear rates.13,14,30 While less than 35 degrees abduction reduces range of motion,15 this may increase impingement of the femoral neck on the cup which may result in wear, and / or dislocation. This in turn may result in higher revision rates.17 In this study the percentage of cases within the traditional safe zone was comparable with other studies but we feel, based on the more recent literature, that the traditional safe zones are too liberal.

These safe zones should be reconsidered if we expect to achieve longevity for our patients, especially with the advent of hard-on-hard bearings, which are even more unforgiving.17,31,32

When we analysed our results based on the aforementioned studies we found that only 72.5% of our patients were within the 35-45 degree safe zone for abduction.

We believe there are certain limitations to the DAA for hip replacements. This would be a limitation to our study in that approximately 10% of primary hip replacements did not fit our selection criteria for using the DAA. This 'cherry picking' may also improve the results for our cup positioning in this study as the very complex cases were treated through a posterior approach. These patients would have required either a rectus femoris reflected head release for acetabular exposure or a piriformis and posterior capsule release for femoral access. Clinically we observed our patients to have more groin pain at 6 weeks with leg elevation in a seated position or a straight leg raise in the supine position than the posterior approach patients if the reflected head was not preserved. Some DAA users routinely incise through reflected head* but we found good visualisation even when preserving it. The piriformis and the posterior capsule are important dynamic and static stabilisers respectively.33 With a posterior approach the capsule and piriformis tendon get repaired and are at least more anatomical than no repair if the posterior capsule and piriformis are released through the DAA in a difficult primary procedure. Furthermore in complex cases with significant shortening the TFL has a higher risk of injury resulting in pain and swelling. If lacerated, it can cause a deformity of the upper lateral thigh, especially noticeable in thin patients.

Further studies are needed to determine whether the DAA still holds value with regard to improved early outcomes in complex primary and revision settings when compared to other approaches.

One of the reasons we believe our results are comparable to other studies despite not using imaging in theatre is that multiple references points are used for cup positioning rather than utilising only one parameter such as local bony landmarks, the transverse acetabular ligament, or external references. Pre-operative templating, the surgeon positioning the patient himself, corrected local bony landmarks with the transverse ligament and external alignment devices followed by immediate post-operative radiological feedback help to refine the cup placement. We also believe in the value of assessing a full range of motion with trial implants, not just looking for frank instability but also for subtle impingement. This is not easily done on a traction table unless the boot is detached from the traction device. Measuring the cup position immediately post-opera-tively improves the surgeon's accuracy of implantation.

When the hip is stable with no impingement through a full range of motion, the version is correct. If there is impingement however, the cup is changed to improve the longevity of the implant.34,35 If there is any posterior instability once leg length and offset have been optimised, there must be retroversion of the cup since the posterior stabilisers, namely the posterior capsule and piriformis, are left intact through this approach. Similarly, if there is over coverage of the cup at the anterior wall with anterior subluxation in leg extension, adduction and external rotation, the cup is excessively anteverted and must be corrected, provided there are no posterior osteophytes causing component-bone conflict. Supplemental screw fixation was required in only 3% of our acetabular implantations, so cup repositioning for subtle impingement or instability was simple. Repositioning was performed in 5% of our patients.

The literature reports a low dislocation rate for the DAA when compared to other approaches. Siguier's dislocation rate was 0.96% (10 out of 1 037).36 Keggi and colleagues37had a dislocation rate of 1.3% in their series of 2 132 primary hips. Matta reported a rate of 0.6%9 and a large multi-centre observational study10 had the same low dislocation rate of 0.6% in 1 152 total hip replacements done via the anterior approach.

We had no dislocations in this small series and we attribute this not only to the approach where the posterior stabilisers remain intact, but also to the good visualisation of the cup and its version through surgery. Being willing to change the position of the cup in the presence of subtle impingement further reduces the risk for dislocation and should improve implant longevity. Saving the piriformis attachment preserves the most important dynamic posterior stabiliser of the hip.



Our study showed similar results to other studies with improved accuracy of acetabular component positioning using the direct anterior approach. It differs from other literature in that the patient positioning remains unchanged from the lateral decubitus positioning that many high volume surgeons are familiar with rather than the patient positioned supine on a traction table. There is also no imaging in theatre during implantation. Further clinical studies are needed to see if this approach can reduce implant impingement and dislocation rates, which would make it an attractive approach for improving implant longevity and reducing re-operation rates.

Compliance with Ethics Guidelines

Dr De Beer is a consultant for Smith and Nephew and Zimmer Biomet.

Drs Deacon and Ryan declare no conflict of interests. All procedures followed were in accordance with the ethical standards approved by the UKZN biomedical research ethics committee. Informed consent was obtained from all patients being included in this study



1. Judet J. The use of an artificial femoral head for arthroplasty of the hip joint. J Bone Joint Surg Br. 1950;32-B: 166-73. Pubmed Central PMCID: 15422013.         [ Links ]

2. Nakata K, Nishikawa M, Yamamoto K, Hirota S, Yoshikawa H. A clinical comparative study of the direct anterior with mini-posterior approach: two consecutive series. The Journal of arthroplasty. 2009 Aug;24(5):698-704. PubMed PMID: 18555653.         [ Links ]

3. Restrepo C, Parvizi J, Pour AE, Hozack WJ. Prospective randomized study of two surgical approaches for total hip arthroplasty. The Journal of Arthroplasty. 2010 Aug;25(5):671-79 e1. PubMed PMID: 20378307.         [ Links ]

4. Goebel S, Steinert AF, Schillinger J, Eulert J, Broscheit J, Rudert M, et al. Reduced postoperative pain in total hip arthroplasty after minimal-invasive anterior approach. International orthopaedics. 2012 Mar;36(3):491-98. PubMed PMID: 21611823. Pubmed Central PMCID: 3291765.         [ Links ]

5. Restrepo C, Mortazavi SM, Brothers J, Parvizi J, Rothman RH. Hip dislocation: are hip precautions necessary in anterior approaches? Clinical Orthopaedics and Related Research. 2011 Feb;469(2):417-22. PubMed PMID: 21076896. Pubmed Central PMCID: 3018228.         [ Links ]

6. Berend KR, Lombardi AV, Jr., Seng BE, Adams JB. Enhanced early outcomes with the anterior supine inter muscular approach in primary total hip arthroplasty. The Journal of Bone and Joint Surgery American volume. 2009 Nov;91 Suppl 6:107-20. PubMed PMID: 19884418.         [ Links ]

7. Spaans AJ, van den Hout JA, Bolder SB. High complication rate in the early experience of minimally invasive total hip arthroplasty by the direct anterior approach. Acta orthopaedica. 2012 Aug;83(4):342-46. PubMed PMID: 22880711. Pubmed Central PMCID: 3427623.         [ Links ]

8. Masonis J TC, Odum s. Safe and accurate: Learning the direct anterior total hip arthroplasty. Orthopedics. 2008;31. Pubmed Central PMCID: 1929801        [ Links ]

9. Matta JM SC, Ferguson T. Single Incision anterior approach for total hip arthroplasty on an orthopaedic table. Clinical Orthopaedics and Related Research. 2005;441:115-24. Pubmed Central PMCID: 16330993.         [ Links ]

10. Anterior Total Hip Arthroplasty Collaborative I, Bhandari M, Matta JM, Dodgin D, Clark C, Kregor P, et al. Outcomes following the single-incision anterior approach to total hip arthroplasty: a multicenter observational study. The Orthopedic Clinics of North America. 2009 Jul;40(3):329-42. PubMed PMID: 19576400.         [ Links ]

11. Woolson ST MC, Syquia JF, Lannin JV, Schurman DJ,. Comparison of primary total hip replacements performed with a standard incision or a mini incision. The Journal of Bone and Joint Surgery American volume. 2004;86(7):1353-58.         [ Links ]

12. Teet JS, Skinner HB, Khoury L. The effect of the 'mini' incision in total hip arthroplasty on component position. The Journal of Arthroplasty. 2006 Jun;21(4):503-507. PubMed PMID: 16781401.         [ Links ]

13. Wan Z, Boutary M, Dorr LD. The influence of acetabular component position on wear in total hip arthroplasty. The Journal of Arthroplasty. 2008 Jan;23(1):51-56. PubMed PMID: 18165028.         [ Links ]

14. Little NJ, Busch CA, Gallagher JA, Rorabeck CH, Bourne RB. Acetabular polyethylene wear and acetabular inclination and femoral offset. Clinical Orthopaedics and Related Research. 2009 Nov;467(11):2895-900. PubMed PMID: 19412648. Pubmed Central PMCID: 2758973.         [ Links ]

15. Kummer FJ SS, Lyer S, et al. The effect of acetabular cup orientations on limiting hip rotation. The Journal of Arthroplasty. 1999;14(4):509-13.         [ Links ]

16. D'Lima DD UA, Buehler KO, et al. The effect of the orien tation of the acetabular and femoral components on the range of motion of the hip at different head neck ratios. The Journal of Bone and Joint Surgery American volume. 2000;82(3):315-21.         [ Links ]

17. Sugano N NT, Miki H et al. Mid-term results of cementless total hip replacement using a ceramic on ceramic bearing with and without computer navigation. J Bone Joint Surg Br. 2007;89(4):455-60.         [ Links ]

18. Hassan DM JG, Dust WN. et al. Accuracy of intraoperative assesment of acetabular prosthesis placement. The Journal of Arthroplasty. 1998;13(1):80-84.         [ Links ]

19. Dymond IW, Ashforth JA, Dymond GF, Spirakis T, Learmonth ID. The usage of image trigonometry in bone measurements. Hip international: the Journal of Clinical and Experimental Research on Hip Pathology and Therapy. 2013 Nov-Dec;23(6):590-95. PubMed PMID: 24062220.         [ Links ]

20. Nishikubo Y, Fujioka M, Ueshima K, Saito M, Kubo T. Preoperative fluoroscopic imaging reduces variability of acetabular component positioning. The Journal of Arthroplasty. 2011 Oct;26(7):1088-94. PubMed PMID: 21676577.         [ Links ]

21. DiGioa AM JB, Blackwell M et al. Image guided navigation system to measure intraoperatively acetabular implant alignment. Clinical Orthopaedics and Related Research. 1998;355:8-22.         [ Links ]

22. Asayama I, Akiyoshi Y, Naito M, Ezoe M. Intraoperative pelvic motion in total hip arthroplasty. The Journal of Arthroplasty. 2004;19(8):992-97.         [ Links ]

23. Lewinnek G, Lewis J, Tarr R. Dislocations after total hip- replacement arthroplasties. The Journal of Bone and Joint Surgery American volume. 1978;60((2)):217-20.         [ Links ]

24. Barrett WP, Turner SE, Leopold JP. Prospective randomized study of direct anterior vs postero-lateral approach for total hip arthroplasty. The Journal of arthroplasty. 2013 Oct;28(9):1634-38. PubMed PMID: 23523485.         [ Links ]

25. Alexandrov T AE, Menendez LR. Early clinical and radiographic results of minimally invasive anterior approach hip arthroplasty. Advances in Orthopedics. 2014.         [ Links ]

26. Hallert O, Li Y, Brismar H, Lindgren U. The direct anterior approach: initial experience of a minimally invasive technique for total hip arthroplasty. Journal of Orthopaedics and Related Research. 2012;7:17. PubMed PMID: 22533964. Pubmed Central PMCID: 3419665.         [ Links ]

27. Todkar M. Obesity does not necessarily affect the accuracy of acetabular cup implantation in total hip replacment. Acta Orthop Belg. 2008;74(2):206-209.         [ Links ]

28. Callanan MC, Jarrett B, Bragdon CR, Zurakowski D, Rubash HE, Freiberg AA, et al. The John Charnley Award: risk factors for cup malpositioning: quality improvement through a joint registry at a tertiary hospital. Clinical Orthopaedics and Related Research. 2011 Feb;469(2):319-29. PubMed PMID: 20717858. Pubmed Central PMCID: 3018230.         [ Links ]

29. McCollum DE Gray WJ. Dislocation after total hip arthroplasty. Causes and prevention. Clinical Orthopaedics and Related Research. 1990;261:159-70.         [ Links ]

30. Tower SS CJ, Currier BH, et al. Rim cracking of the cross linked longevity polyethylene acetabular liner after total hip arthroplasty. The Journal of Bone and Joint Surgery American volume. 2007;89(10):2212-17.         [ Links ]

31. Hart AJ, Ilo K, Underwood R, Cann P, Henckel J, Lewis A, et al. The relationship between the angle of version and rate of wear of retrieved metal-on-metal resurfacings: a prospective, CT-based study. J Bone Joint Surg Br. 2011 Mar;93(3):315-20. PubMed PMID: 21357951.         [ Links ]

32. De Haan R, Pattyn C, Gill HS, Murray DW, Campbell PA, De Smet K. Correlation between inclination of the acetabular component and metal ion levels in metal-on-metal hip resurfacing replacement. J Bone Joint Surg Br. 2008 Oct;90(10):1291-97. PubMed PMID: 18827237.         [ Links ]

33. Moussallem CD HF, Lahoud JC. Incidence of piriformis tendon preservation on the dislocation rate of total hip replacement following the posterior approach: a series of 226 cases. J Med Liban. 2012 Jan-Mar;60(1):19-23. Pubmed Central PMCID: 22645897.         [ Links ]

34. Shon WY, Baldini T, Peterson MG, Wright TM, Salvati EA. Impingement in total hip arthroplasty a study of retrieved acetabular components. The Journal of Arthroplasty. 2005 Jun;20(4):427-35. PubMed PMID: 16124957.         [ Links ]

35. Yamaguchi M AT, Bauer TW, et al. The spatial location of impingement in total hip arthroplasty. The Journal of Arthroplasty. 2000;15(305).         [ Links ]

36. Siguier T SM, Brumpt B. Mini-incision anterior approach does not increase dislocation rate: a study of 1037 total hip replacement. Clinical Orthopaedics and Related Research. 2004;426:164-73.         [ Links ]

37. Keggi Jk, Hou. HM, Zatorski. LE. Anterior approach to total hip replacement: surgical technique and clinical results of our first one thousand cases using non- cemented prostheses. Yale Journal of Biology and Medicine. 1993;66:243-56.         [ Links ]



Dr Mark Deacon
Prince Mysheni Memorial Hospital
Griffiths Mxenge Highway
4060 Umlazi

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