Minimally Invasive Total Hip Replacement:

 An Overview of the Results

 

Instructional Course Lectures

 

Volume # 57

 

 

Paul J. Duwelius, M.D.*

Lawrence D. Dorr, M.D. **

 

 

 

 

 

 

 

 

 

 

 

 

* Adjunct Associate Professor of Orthopedics Oregon Health Sciences University

Clinical Attending St Vincent Hospital and Medical Center

Portland, Or.

 

**Arthritis Institute

501 E. Hardy Street, 3rd Floor

Inglewood, CA  90301

Phone:  310-695-4800

FAX: 310-695-4802

EMAIL:  Patriciajpaul@yahoo.com

 

 

CORRESPONDENCE TO:

 

Paul J. Duwelius, M.D.

Orthopedic & Fracture Clinic

11782 SW Barnes Rd. #300

Portland, Or. 97225

Fax: 503-906-6613

EMAIL: Beverly.haynes@providence.org

http://www.ofc-oregon.com

 

ABSTACT

Small incision total hip arthroplasty is shown to be safe and achieves its goals of early postoperative improvement in pain and function.  The comparative published reports of the two-incision, anterior, and mini posterior techniques have defined indications for small incision total hip arthroplasty.   The mini posterior approach appears to be better than the traditional posterior total hip arthroplasty for early patient function and acceptance.  Between the small incision operations there may be little difference when the preoperative patient education and postoperative recovery are identical.  

The safety of small incisions has been established because correct component positioning has been achieved consistently with these procedures and short-term results of small incision surgery are the same as that of long incisions.  The mini posterior approach has been shown to have psychological advantages by allowing some patients to have more confidence in their outcome.   New anesthesia and pain management techniques have led to improved early functional results.   With time, and technical advances such as computer navigation, minimally invasive total hip replacement will become more prevalent.  

 

 

 

 

 

Key words:     arthroplasty, hip replacement, minimally invasive, new process of THR, MIS results

INTRODUCTION:

The focus of minimally invasive surgery (MIS) is to improve early pain which helps to improve immediate function.   The benefit of less invasive surgery is experienced by the patient in the early postoperative period.  The goals of MIS do not anticipate that this is a change in total hip replacement that will affect long term durability.  Although the media and internet have been criticized for promoting minimally invasive total joint surgery, in reality, it has been driven by patients because it creates a positive psychological experience for the patient1.  Multiple recent studies suggest that patient satisfaction with MIS is very high2,3,4,5,6,7.

            The benefits of minimally invasive surgery compared to traditional surgical approaches in total hip arthroplasty have been questioned by surgeons because there has not been any conclusive scientific data that physical benefits exist for the patient as measured by traditional scoring instruments 2,8,9.   Total hip surgery using long incisions has proven results and it is understandable why some surgeons are reluctant to perform small incision surgery 10.   Much of the skepticism is secondary to misunderstanding of the goals and benefits.  This is simply a new surgical approach and not a new operation. There was skepticism by Charnley advocates when the posterior approach replaced the trochanteric osteotomy approach, yet today, trochanteric osteotomy is not used for primary operations. 

Small incision surgery gives patients more hope that the outcome they envision will be achieved 7.   Patients want pain relief and they want their functional goals, but true satisfaction in any orthopedic operation is not achieved without the patient gaining their psychosocial goals11,12,13,14,15.   Patients want their independence and to regain control of their lifestyle (15,16).  Minimally invasive surgery gives patients more confidence in regaining control of their independence, and the confidence that they can achieve their goals and expectations.  However, patients will not get any psychological benefit if their complications are greater, or their pain relief and functional recovery are not achieved. Therefore, the operation must be as safe as with a traditional length incision. The purpose of this instructional course chapter of small incision total hip arthroplasty surgery is to establish , by evidence-based data, that it is safe, that it achieves the goal of short term improvement, and that it does give patients more confidence in their outcome.

 TECHNIQUE GUIDELINES

Minimally invasive surgery is more complex than surgery done through a larger incision because at any given moment not all the surgical field is exposed17 . Minimally invasive surgery therefore requires a commitment to learning the special techniques associated with the greater degree of difficulty. Achieving correct exposure must occur for the safety of MIS surgery. The second factor involved in small incision surgery is the specialized instrumentation that allows the surgeon to operate through the soft tissue windows of these particular approaches. Difficulties can be minimized if specialized instruments developed for each technique are used 2,5,10,17,18. These instruments include lighted retractors, curved acetabular insertion guides, beveled (half-size) acetabular reamers to facilitate insertion and removal to avoid skin and muscle injury, and femoral stem insertion handles to avoid varus stem position and protection of muscles.

The common characteristics of all the MIS approaches are the need for adequate training and the use of specialized instruments specific to each surgical technique.  All minimally invasive surgical techniques cause some soft tissue injury, but the goal of these operations is to reduce soft tissue trauma below the level of the skin.   The use of specific instrumentation is critical in mobilizing the surgical window without unnecessary tissue damage to see the appropriate landmarks and anatomy.   Trained assistants facilitate the procedure enormously because they know how to use the wound as a mobile window 17,19,23,37.   If visualization is not sufficient, single incision techniques facilitate extension of the incision for improved visualization.  

Intraoperative landmarks for some incisions are different from standard surgery as less bone is visualized and different references are necessary.   The changes from the normal surgical references is most obvious with the two-incision operation which is performed in the supine position and requires fluoroscopy for component

positioning2,3,5,20,21,22,23.  The two-incision technique is done between muscle planes as is the anterior incision.   The posterior incision and the anterolateral incision incise muscle during the exposure.  There has been no postoperative clinical benefit observed in those patients in whom there is no muscle cut.   In all the incisions there is the vision of the capsule, removal of the femoral head, and retraction of the femur for exposure of the acetabulum.   Each of the minimally invasive approaches is specifically described in this Instructional Course lecture volumes.

The importance of minimally invasive hip surgery is not just a shorter skin incision, but performing the operation with less incision of the deep hip tissues. For this reason, minimally invasive techniques are described as tissue sparing procedures.  Cadaver studies have shown that retractor damage in the “no muscle cut incisions” is equivalent to damage in the posterior mini-incision 24,25.    Some muscle damage is present with all small incision approaches. 

An example of less tissue trauma occurs in the posterior mini incision where there are four differences in muscle damage between the mini and the long incision operations:

 1) no incision is made into the tensor fascia for the mini-incision group; 2) the gluteus maximus muscle is split for only 6 cm in the mini-incision group versus 10-12 cm with a long incision; 3) the gluteus maximus tendon is not released in the mini-incision group, but it is released in the long incision group and repaired at the completion of the arthroplasty; and 4) the quadratus femoris muscle is not released with the mini-incision group, but is released with the long incision group10,26,27.

Computer navigation can be of great benefit for correct component positioning with the decreased visualization of minimally invasive surgery28. Correct numerical inclination and anteversion are displayed by the software with adjustments made for the tilt of the pelvis. This has been seen to increase the accuracy of component placement in many studies 28,29,30,31,32,33.

IMPACT OF MINIMALLY INVASIVE TOTAL HIP ARTHROPLASTY ON THE PATIENT

Multiple factors play a role in the success of minimally invasive total hip surgery.  Patients have anxiety preoperatively that they will not achieve their goals and expectations and will be more crippled postoperatively.  Patients’ disability may cause loss of control of their independent life which results in anxiety and depression 7,13,14,15,34.    Preoperative patient education is required to alleviate this anxiety and give them confidence in the success of the operation 7,17,34,35,36,37.   Patients must be educated that there are three goals for success:  pain relief, return of function, and satisfaction.   Hudak et al11,12 have defined satisfaction with an orthopedic operation to mean the patient feels unselfconscious with their result and have incorporated the defective limb back into their whole body image.

Minimally invasive total hip replacement surgery means to the patient less trauma, which translates to more confidence in achieving the outcome they envision 7,37.    The cosmesis of the wound symbolizes less violation of their body and all the psychological benefits that accrue from that.   Preoperatively, it is important for the physician to determine the patient’s most important reason for undergoing the operation (usually mobility and pain relief), and then find out their goals (expectations).   If one of the goals is small incision and rapid recovery, and this goal is not realistic for that patient, the surgeon must educate that patient on the limitation of their expectation and establish new goals that the patient can achieve.  Realistic goals are critical for satisfaction, and the most satisfied patients are those who exceed their expectations12. 

Patients identify a small incision with helping them achieve all three components of success (pain, function, satisfaction) as evidenced in the study of Dorr et al 7 which reported a psychological survey of 165 patients with 56 having a traditional long posterior incision and 109 a small posterior mini-incision.  Both preoperatively, and even more so at six weeks postoperatively, all patients (even those with long incisions) believed that a small incision would enhance all three areas of recovery.   At six weeks the patients with a small incision had exceeded their expectations, which promoted ultimate satisfaction with their operation.  By six months to one year all patients had achieved their primary goals of the operation of pain relief and return of function and the length of the incision was less important.   In spite of this, 4 out of 10 patients with a long incision still wished that they had a small incision, so that they had not achieved satisfaction.  The reasons given by these patients suggested that they were still self conscious about their hip and had not reincorporated their hip into their whole body image.  

The explanation for this positive effect of the incision on the patient, in spite of a lack of physical evidence of improvement in scientific studies, may be the concept of implicit cognition which means that patients have an unconscious prejudice towards something because of a prior experience38.  A second reason may be the halo effect which means that patients transfer an expectation to some event based on prior experience even though the current event (hip replacement for these patients) is not relevant to the prior experience39.   An example would be that patients have the expectation that a large vs. small incision for total hip replacement would be equivalent to the difference in an injury that resulted from a large gash vs. a small scratch.

SAFETY OF MINIMALLY INVASIVE TOTAL HIP ARTHROPLASTY:

With any new incisional approach, complications and long term outcomes should not be compromised8,10,40.  One frequently quoted study reported complications of wounds and component positions with a posterior mini incision and suggested that these incisions should not be performed 41 .  On the other hand, studies from multiple centers have demonstrated that minimally invasive surgery does not compromise component position or increase postoperative complications 4,19,20,30,35,42,43,44,45,46,47,48,49.    Randomized prospective studies, such as that of Oganda et al 44, have compared a traditional posterior approach to a mini-posterior approach and concluded that both were safe and reproducible because the component positions were the same, complications were the same, and there was no difference in walking ability or length of hospital stay.  Sculco et al 48 initially undertook a pilot study to evaluate the benefits of small incision surgery and concluded that the procedure was safe.   They subsequently undertook a randomized prospective study confirming their preliminary results4.    Eslam et al 49, in a prospective randomized study, reported safe and reproducible results with the anterior mini-incision approach compared to the standard anterior approach.  Several retrospective studies have confirmed the safety of minimally invasive total hip arthroplasty 2,5,19,20,30,35,43,47,48,50,51,52.    A five year followup of Sculco’s patients concluded this technique did not influence the clinical and radiographic results for as long as five years 48.  Floren and Lester42 reported 10 year results of patients operated with a posterior mini-incision and found no compromise to the durability of the operations. 

            In several studies, the two incision MIS has had the most reported complications.  Several authors report a steep learning curve for the two-incision technique which was more than 10 surgeries with complications inherent to the technique still occurring beyond 25 surgeries45,53,54,55.    The most prevalent complication was periprosthetic fractures with a range of occurrence of 1 to 6%.  Likewise, Pagnano et al.55 in a randomized comparison of posterior mini to two incision operations, found an increased occurrence of periprosthetic fractures (4%) with the two-incision technique.   However, the incidence of fractures reported with the two incision technique is not greater than that reported by Berend et al56,57 with long incisions.  They had 26 of 1959 (1.3%) fractures with posterior incisions and 32 of 476 (6.3%) with anterior operations.  This data suggests that the two-incision operation is not fraught with a clinically significantly increased rate of fractures.  

            Berger and Duwelius20 did not observe an increased fracture rate (2%) with the two-incision operation.   A comparison of the results reported by Pagnano et al 6, and those of Berger and Duwelius 20 shows two distinct differences in technique that may have contributed to their disparate results.   First, there were two different femoral stems used which may have contributed to the difference in fractures; secondly, Pagnano operated more obese women than did Berger.   Other than periprosthetic fractures, injury to the lateral femoral cutaneous nerve in 10-20% of patients was common to both series with resolution of the nerve deficit in most patients.  

MIS AND FUNCTION RECOVERY

            The goal of MIS is to reduce pain and thereby increase the immediate function after total hip replacement.   Almost all the same studies that showed equivalent safety between long and short incisions also showed equivalent functional recovery4,30,43,44,47.   These studies all used the same physical therapy program for the patients postoperatively.   When all patients are treated with an identical program and goals, this is termed a passive therapy program.   To differentiate whether or not small incision surgery can allow patients to function better and faster, it is necessary to employ an active physical therapy program.  An active physical therapy program is one that is adapted to each individual patient and allows that patient to improve according to their capability.   In the randomized prospective study of Dorr et al 58, an active rehabilitation program was used.  Patients were encouraged to be discharged within 48 hours on a single assistive device.   Twenty-nine of 30 patients (97%) with a posterior mini-incision operation were discharged by the second postoperative day compared to 20 of 30 (67%) patients with a long incision (p = 0.003).   Twenty-six of 30 patients (86.7%) with the mini-incision were discharged on a single assistive device (single cane or crutch) as compared to 16 patients (63.3%) with a long incision (p = 0.005).   Kahn et al 43 did not randomize their patients, but did confirm that patients with a mini-posterior incision were discharged earlier. 

            The randomized study of Chimento et al4 (Sculco) did find that patients with the posterior mini-incision had less limp for as long as six weeks postoperatively.  

DiGioia et al.30, using the posterior mini-incision, reported their patients had less limp (p < 0.05) and better ability to climb stairs (p < 0.01) which was maintained through 6 months postoperatively.   Finally, Pagnano et al 55 in a randomized comparison of posterior mini-incision to the two-incision operations found recovery from the posterior incision to be easier and faster than with the two-incision approach.  

            The greatest advancement in functional recovery for total hip replacement has been the advent of same day discharge for these patients.   Berger et al 34 pioneered this rapid return to function allowing same day discharge with patients that had a two-incision operation.    In their series, there were no readmissions, complications, or patient dissatisfaction with going home the same day as surgery.   A matched-pairs study of posterior mini-incision and two-incision patients by Duwelius et al5 also suggested that patients with the two-incision operation returned to function most quickly.  

Clearly though, the studies discussed in this section show that more rapid hospital discharge and a very rapid return to function has occurred in patients with all MIS incisions.   

NEW PROCESS OF THR WITH MIS:

            Anesthetic techniques, pain management protocols, and rapid recovery therapy have been developed in parallel with the use of small incision surgery.   These techniques are as important as the incision for implementation of reduced hospitalization and more rapid functional recovery5,34,35,58,59.    Regional anesthesia is favored over general anesthesia for patient satisfaction postoperatively by avoiding nausea and vomiting and a malaise associated with general anesthesia.    If narcotics are not used in the epidural or spinal, and intravenous narcotics are avoided, there is little postoperative emesis59.   Regional anesthesia should allow the patient to rapidly move their feet and legs in the recovery room which gives comfort to the surgeon and the patient, and allows the patient to be mobilized out of bed within 2 hours of their operation.    The anesthetic technique was of less importance in previous years when parenteral narcotics were used for pain control, and patients were not mobilized out of bed for the first one or two days. Propofol (Novaplus, Wilmington, De.) used as an intraoperative sedative allows the patient to be fully awake immediately after the cessation of this intravenous drug. 

The use of regional anesthesia and sedation, the effects of which can be rapidly dissipated, has profoundly changed the postoperative attitude of the patient toward their recovery.   The anxiety and dissatisfaction that accompanies nausea and vomiting7,34,58 as well as the lethargy present with parenteral narcotics, creates a bad memory of the operative experience for the patient.   The experience of the patient with their operation will influence their desire to have another joint operated when necessary. Furthermore, a satisfied patient will influence other friends and family members to have the procedure done based on the referring patients’ positive experience.   This is one of the reasons why there are such a high number of patients in the United States who are underserved in the treatment of their arthritic joints60.

            The second important change of treatment of patients has been the pain management protocols.   Pain is now prevented with a multimodal analgesic protocol that provides protection against pain at the peripheral wound site, the spinal cord transmission, and the brain.   Wound injections give a high level of pain relief as shown in studies by Lombardi et al. 61  and Busch et al. 62.   Pain transmission through the spinal cord (dorsal horn neurons and spinothalamic tract) to the brain is blocked intraoperatively with regional anesthesia.   

            The pain management protocol includes administration of cox -2 inhibitors, pain medication, and an antiemetic one hour preoperatively.   No intravenous narcotics, spinal or epidural narcotics, are used by anesthesia.  In the recovery room oral pain medications

(Oxy-R, 5 mg) and intravenous Keterolac are used for pain, with intravenous narcotics administered as needed for breakthrough pain.   For the remainder of the hospitalization, oral pain medications are used which must be adapted to the patient’s age and pain tolerance59.  

Pain can be modified by using cox-2 inhibitors which block the cyclooxygenase enzymes which are transmitters of the pain through the spinal cord to the thalamus.  In the brain, the patient can be modified in the thalamus by using a cox-2 inhibitor and a cox-3 inhibitors (Tylenol, acetaminophen Amneal Pharmaceuticals, Patterson, NJ).    The response in the brain can also be modified by the preoperative education class which can condition the patient that their pain can be controlled postoperatively and that they should not anticipate having significant pain, which helps sensitization of the central response.

The effect of this multimodal program which avoids parenteral narcotics, and uses only oral medications, is shown in the study of Dorr et al59.   When this program was combined with a posterior MIS incision, the average pain scores after administration of the oral medications was 1 on an analog scale of 10.   The pain scores prior to medication were only slightly above 2.   The incidence of emesis was 3.7%.  A multimodal program directed toward the elimination of parenteral narcotics and the use of oral pain medications combined with wound injections is highly effective in controlling the pain of total hip replacement patients with minimally invasive surgery 5,34,59,61,62.  

            The third factor in the new process of total hip replacement is an active physical therapy program.  An active physical therapy program promotes progress of the patient being determined by the capability of that individual patient rather than a physical therapy pathway used in common for all patients.   An active physical therapy program allows patients to go home on the same day of the operation if they can do so.  It allows patients to do their own physical therapy at home without supervision from a therapist, when the patient will take that responsibility.   Patients can initiate a walking program immediately following discharge and combine that with stretching exercises for flexibility and can achieve results at their own pace according to their own motivation.   This program has also allowed patients to return to work within days after their operation rather than at three months as was the traditional time frame5,34,58.   The impact of an active physical therapy program on functional recovery after MIS was discussed in the “MIS and Functional Recovery” section of this chapter.  

SUMMARY:

            MIS is a disruptive technology.   As such, its technology creates an environment of change and stress among practioners of standard incisions.  The advantages of small incisions are common-sense for all – small injuries are preferable to large ones.   The conflict arises because the surgeon has to learn to work in a smaller operative field and has more stress during the operation.  Justification for avoidance by surgeons of the change and stress has been the absence of positive evidence-based scientific benefits by traditional measurement methods.   Equivalence of safety and function in randomized studies4,44,55,58 has not been enough to support change.  

            MIS is simply a change in surgical incisions and exposure.  Previous changes in incision and exposure created some disruption, but were quickly assimilated into the techniques used by surgeons.  The posterior approach avoided trochanteric osteotomy and the complication of non-union, as well as allowing patients to be full weight bearing immediately after the operation.  Charnley did not embrace this change and recommended against using it because it affected his biomechanical theory of leveling moment arms by lateralizing the trochanter.   The simplicity of the technique, however, quickly won the day.  Hardinge et al.63 altered the anterior approach by cutting part of the gluteus medius muscle which increased exposure.   This approach was adopted by the advocates of the PCA hip prosthesis (porous coated anatomic, Howmedica, Rutherford, NJ) which helped popularize it.   It did not convert posterior hip surgeons who did not like cutting the gluteus medius muscle, but anterior hip surgeons changed to it because it simplified the exposure.   These previous changes simplified the exposure and the stress for the surgeon while MIS reduces the exposure and increases the stress.   Therefore, like all disruptive technologies, the change will gradually be accepted.     

            In this chapter we have shown that the scientific evidence overwhelmingly confirms the safety of total hip replacement by small incisions.   If component positions do not differ, the durability of the operation will not be different.   In all randomized studies, the complications between small and long incisions do not differ,4,44,55,58.  Small incision operations, either posterior or anterior, are safe.  

            Small incision operations were developed to reduce pain and improve function.   The changes in the process of total hip replacement, which were initiated to support MIS, have promoted less pain and earlier function.  When these changes in anesthesia, pain management, and recovery were compared in posterior MIS and long incisions by Dorr et al 58, patients with small incisions performed superiorly.   Active physical therapy programs, which allow the patient to progress at his/her own capability and motivation, will replace passive programs which treat all patients the same.  With active physical therapy programs, MIS operations will be beneficial for the patients 58.

A final complaint against MIS is that high volume surgeons can effect this change, but low volume surgeons will have higher complications.  We do not accept this caveat because low volume joint replacement surgeons often operate in high volume in other areas of orthopedics.   These surgeons have good psychomotor skills and can adapt their incisional approaches when given appropriate education, good instrumentation, and combine these with their cognitive skills, forward planning, and error detection, which are the characteristics of any good surgeon. 


Bibliography

 

 

 1.        Klein GR, Parvizi J, Sharkey PF, Rothman RH, Hozack WJ. Minimally invasive total hip arthroplasty: internet claims made by members of the Hip Society. Clin Orthop Relat Res. Dec 2005;441:68-70.

 

 2.        Berry,D.J., Berger,R.J., Callaghan,J.J., Dorr,L.A., Duwelius,P.J., Hartzband, M.A., Lieberman,J,R., Mears, D.A.: Minimally Invasive Total Hip Arthroplasty: Development, Early Results, and a Critical Analysis. J Bone & Joint Surgery 85-A: 2235-2255, 2003

 

 3.        Berger, RA; The technique of minimally invasive hip surgery using the two incision approach. Instr Course Lect 2004; 53, pp.149-55.

 

 4.        Chimento GF, Pavone V, Sharrock N, Kahn B, Cahill J, Sculco TP. Minimally invasive total hip arthroplasty: a prospective randomized study. J Arthroplasty. Feb 2005;20(2):139-144

 

 5.        Duwelius, PJ, Burkhart, RL, Hayhurst, JO, et al: Comparision of the 2-incision and mini-posterior total hip arthroplasty technique. J.of Arthroplasty. Jan 2007;22 (1):pp. 48-56.

 

6.        Pagnano MW, Leone J, Lewallen DG, Hanssen AD. Two-incision THA had modest outcomes and some substantial complications. Clin Orthop Relat Res. Dec 2005;441:86-90.

 

 7.        Dorr, LD, Sirianni, LE, Thomas,D, et al: Psychological reasons for patients preferring minimally invasive total hip arthroplasty. Clinical Orthopedics and Related Research May, 2007 (In Press)

 

 8.        Ranawat CS, Ranawat AS. Minimally invasive total joint arthroplasty: where are we going? J Bone Joint Surg Am. Nov 2003;85-A(11):2070-2071.

 

 9.        Woolson, ST, In the absence of evidence-why bother? A literature review of minimally invasive total hip replacement surgery: Instr Course Lectr 2006, 55 p 189-93

 

10.       Keener JD, Callaghan JJ, Goetz DD, Pederson D, Sullivan P, Johnston RC. Long-term function after Charnley total hip arthroplasty. Clin Orthop Relat Res. Dec 2003(417):148-156

 

11.       Hudak PL, Hogg-Johnson S, Bombardier C, Mckeever PD, Wright  JG. Testing a new theory of patient satisfaction with treatment outcome. Med Care. Aug 2004;42(8):726-739.

 

12.       Hudak PL, McKeever PD, Wright JG. Understanding the meaning of satisfaction with treatment outcome. Med Care. Aug 2004;42(8):718-725.

 

13.       Iverson MD, Daltroy LH, Fossel AH, Katz JN. The prognostic importance of patient preoperative expectations of surgery for lumbar spinal stenosis. Patient Edu Couns. 1998;34:169-178.

 

14.       Mancuso CA, Salvati EA, Johanson NA, Peterson MGE, Charlson ME. Patients’ expectations and satisfaction with total hip arthroplasty. J Arthroplasty.  1997;12:387-396

 

15.       Chamberlain K, Petrie, K, Azarih R: The role of optimism and sense of coherence in predicting recovery following surgery.   Psychology and Health, 7:301-310, 1992

 

16.       Orbell S, Johnston M, Rowley D, Espley A, and Davey P: Cognitive representations of illness and functional and affective adjustment following surgery for osteoarthritis.  Soc. Sci. Med. 47:93-102, 1998.

 

17.       Howell JR, Garbuz DS, Duncan CP. Minimally invasive hip replacement: rationale, applied anatomy, and instrumentation. Orthop Clin North Am. Apr 2004;35(2):107-118.

 

18.       Yerasimides JG, Matta JM. Primary Total Hip Arthroplasty With a Minimally Invasive Anterior Approach. Vol 16 Seminars in Arthroplasty. Philadelphia, PA: Elsevier; 2005.

 

19.       Hartzband, MA; Posterolateral minimal incision for total hip replacement: technique and early results. Orthop Clin North Am 2004 Apr; 35 (2), pp. 131-6

 

20.          Berger, R.A., Duwelius, P.J.:  The Two-Incision Minimally Invasive Total Hip Arthroplasty: Technique and Results, Orthopedic Clinics of North America; Vol. 35 p 163-171, April 2004

 

21.       Berger, RA; The technique of minimally invasive hip surgery using the two incision approach. Instr Course Lect 2004; 53, pp.149-55.

 

22.       Berger, RA: Total hip arthroplasty using the minimally invasive two incision approach. Clin Orthop 2003 Dec (417), pp.232-41.

 

23.       Duwelius, PJ, Two- Incision minimally invasive total hip arthroplasty: Techniques and results to date. Instr Course Lectr 2006, 55 p 215-222

 

24.       Mardones R, Pagnano MW, Nemanich JP, Trousdale RT. The Frank Stinchfield Award: muscle damage after total hip arthroplasty done with the two-incision and mini-posterior techniques. Clin Orthop Relat Res. Dec 2005;441:63-67.

 

25.       Meneghini RM, Pagnano MW, Trousdale RT, Hozack WJ. Muscle Damage During MIS Total Hip Arthroplasty: Smith-Peterson versus Posterior Approach. Clin Orthop Relat Res. Sep 21 2006.

 

26.       Inaba Y, Dorr LD, Wan Z, Sirianni L, Boutary M. Operative and patient care techniques for posterior mini-incision total hip arthroplasty. Clin Orthop Relat Res. Dec 2005;441:104-114.

 

27.       Teet JS, Skinner HB, Khoury L. The effect of the "mini" incision in total hip arthroplasty on component position. J Arthroplasty. Jun 2006;21(4):503-507.

 

28.       Murphy SB, Ecker TM, Tannast M. THA Performed using Conventional and Navigated Tissue-preserving Techniques. Clin Orthop Relat Res. December 2006;453:160-167.

 

29.       DiGioia AM, 3rd, Blendea S, Jaramaz B. Computer-assisted orthopaedic surgery: minimally invasive hip and knee reconstruction. Orthop Clin North Am. Apr 2004;35(2):183-189.

 

30.       DiGioia AM, 3rd, Plakseychuk AY, Levison TJ, Jaramaz B. Mini-incision technique for total hip arthroplasty with navigation. J Arthroplasty. Feb 2003;18(2):123-128.

 

31.       Wixson RL, MacDonald MA. Total hip arthroplasty through a minimal posterior approach using imageless computer-assisted hip navigation. J Arthroplasty. Oct 2005;20(7 Suppl 3):51-56.

 

32.       Kalteis T, Handel M, Bathis H, Perlick L, Tingart M, Grifka J. Imageless navigation for insertion of the acetabular component in total hip arthroplasty: is it as accurate as CT-based navigation? J Bone Joint Surg Br. Feb 2006;88(2):163-167

 

33.       Nogler M, Kessler O, Prassl A, et al. Reduced variability of acetabular cup positioning with use of an imageless navigation system. Clin Orthop Relat Res. Sep 2004(426):159-163.

 

34.       Berger RA, Jacobs JJ, Meneghini RM, Della Valle C, Paprosky W, Rosenberg AG. Rapid rehabilitation and recovery with minimally invasive total hip arthroplasty. Clin Orthop Relat Res. Dec 2004(429):239-247

 

35.       Ranawat C.S, Ranawat, RA. The effect of Modifying the Acute Postoperative Pain Response after Total Hip and Knee Replacement using Reduced Tissue Trauma Surgery. Paper presented at: AAOS ANNUAL MEETING, 2006; Chicago.

36.       Howell JR, Masri BA, Duncan CP. Minimally invasive versus standard incision anterolateral hip replacement: a comparative study. Orthop Clin North Am. Apr 2004;35(2):153-162

37.       Szendroi M, Sztrinkai G, Vass R, Kiss J. The impact of minimally invasive total hip arthroplasty on the standard procedure. Int Orthop. Jun 2006;30(3):167-171.

 

38.       Greenwald AG, Mahzarin BR. Implicit social cognition: attitudes, self esteem and sterotypes. Psychological Review. 1995;102:4-27

 

39.       Thorndike EL.  A constant error in psychological ratings. Journal of Applied Psychology. 1920;4:12-2945.

 

40.       Teet JS, Skinner HB, Khoury L. The effect of the "mini" incision in total hip arthroplasty on component position. J Arthroplasty. Jun 2006;21(4):503-507.

 

41.       Woolson, ST, Mow. CS, Syquia JF, Lannin, JV, Schurman, DJ: Comparison of primary total hip replacements performed with a standard incision or a mini incision. JBJS; July 2004; Vol 86-A, pp. 2235-224

 

42.              Floren M, Lester DK. Durability of implant fixation after less-invasive total hip arthroplasty. J of Arthroplasty. Sep 2006;21(6):783-790.

 

43.              Khan RJ, Fick D, Khoo P, Yao F, Nivbrant, B, Wood, D. Less invasive total hip arthroplasty: description of a new technique. J Arthroplasty. Oct 2006;21(7):1038-1046.

 

44.              Oganda, L, Wilson, R, Archbald, P, Lawlor, M, Humphreys, P O’Brien, S, A minimal incision technique does not improve early postoperative outcomes. A prospective randomized controlled trial. JBJS Am. 2005 Apr; 87(4): 699-700.

 

45.       Pagnano MW, Trousdale RT, Meneghini RM, Hanssen AD. Patients Preferred a Mini-Posterior THA to a Contralateral Two-Incision THA. Clin Orthop Relat Res. Sep 21 2006

 

46.       Sculco TP. Minimally invasive total hip arthroplasty: in the affirmative. J Arthroplasty. Jun 2004;19(4 Suppl 1):78-80.

 

47.       Wright JM, Crockett HC, Delgado S, Lyman S, Madsen M, Sculco TP. Mini-incision for total hip arthroplasty: a prospective, controlled investigation with 5-year follow-up evaluation. J Arthroplasty. Aug 2004;19(5):538-545.

 

48.       Sculco TP, Jordan LC, Walter WL. Minimally invasive total hip arthroplasty: the Hospital for Special Surgery experience. Orthop Clin North Am. Apr 2004;35(2):137-142.

 

49.       Eslam PA, Parvizi J, Sharkey PF: Minimally Invasive Hip Arthroplasty: What Role Does Patient Preconditioning Play? JBJS Am. Aug. 2007(In Press).

 

50.       Swanson, TV, Early results of 1000 consecutive, posterior, single incision minimally invasive surgery total hip arthroplasties. J Arthroplasty, Oct 2005, 20(7 Suppl 3) p 26-32.

 

51.              Waldman, B.J.: Minimally invasive total hip replacement and perioperative management: early experience. J. South Orthopaedic Assoc. 2002; 25: 1031-1043.

 

52.              Wenz, J.F., Gurkan, L., Jibodh, S.R., Mini-incision total hip arthroplasty: a comparative assessment of perioperative outcomes. Orthopaedics, 2002; 25: 1031-43

 

53.              Archibeck MJ, White RE, Jr. Learning curve for the two-incision total hip replacement. Clin Orthop Relat Res. Dec 2004(429):232-238

 

54.       Bal, BS, Haltom, D, Aleto, T, Barrett, M, Early complications of primary total hip replacement performed with the two incision technique. JBJS Am. 2005 Nov; (11): 2432-8

 

55.       Pagnano M, Trousdale R, Leone J, Meneghini R, Hanssen AD. A Prospective Randomized Clinical Trial Shows That Two-Incision Total Hips Recover More Slowly Than Mini-Posterior Total Hips. J Bone Joint Surg Am. 2006;In Review.

 

56.       Berend KR, Lombardi AV, Jr., Mallory TH, Chonko DJ, Dodds KL, Adams JB. Cerclage wires or cables for the management of intraoperative fracture associated with a cementless, tapered femoral prosthesis: results at 2 to 16 years. J Arthroplasty. Oct 2004;19(7 Suppl 2):17-21.

 

57.       Berend ME, Smith A, Meding JB, Ritter MA, Lynch T, Davis K. Long-term outcome and risk factors of proximal femoral fracture in uncemented and cemented total hip arthroplasty in 2551 hips. J Arthroplasty. Sep 2006;21(6 Suppl 2):53-59.

 

58.              Dorr, LD, Maheswari, Long, WT, et al: Early pain and functional results comparing minimally invasive to conventional total hip arthroplasty: A prospective, randomized blinded study. JBJS Am. June, 2007(In press)

 

59.              Maheshwari AV, Boutary M, Yun AG, Sirianni LE, Dorr LD. Multimodal Analgesia without Routine Parenteral Narcotics for Total Hip Arthroplasty. Clin Orthop Relat Res. Oct 5 20069.

 

60.       Hawker GA, Wright JG, Coyte PC, Williams JI, Harvey B, Glazer R, and Badley EM: Differences between men and          women in the rate of use of hip and knee arthroplasty. New Eng Journal of Medicine, 342:1016-1022, 2000.

 

61.       Lombardi AV, Jr., Berend KR, Mallory TH, Dodds KL, Adams JB. Soft tissue and intra-articular injection of bupivacaine, epinephrine, and morphine has a beneficial effect after total knee arthroplasty. Clin Orthop Relat Res.        Nov 2004(428):125-130.

 

 

62.       Busch CA, Shore BJ, Vhandri FR, Ganapathy S, MacDonald SJ, Bourne RB, Rorabeck CH, and McCalden RW:     Efficacy of periarticular multimodal drug injection in total knee arthroplasty. A randomized trial. J Bone Joint Surg 88A:959-963, 2006

 

 

63.       Hardinge, K: The direct lateral approach to the hip. J Bone Joint Surgery (Br) 64(1): 17-9, 1982.

 

 

 

 

 

 

 

 

 

 

 

 

 

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