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Although metal-on-metal (MoM) bearing surfaces provide low rates of volumetric wear and increased stability, evidence suggests that certain MoM hip arthroplasties have high rates of complication and failure. Some evidence indicates that women have higher rates of failure compared with men; however, the orthopaedic literature as a whole has poorly reported such complications stratified by gender.This systematic review aimed to: (1) compare the rate of adverse local tissue reaction (ALTR); (2) dislocation; (3) aseptic loosening; and (4) revision between men and women undergoing primary MoM hip resurfacing arthroplasty (HRA).Systematic MEDLINE and EMBASE searches identified all level I to III articles published in peer-reviewed journals, reporting on the outcomes of interest, for MoM HRA. Articles were limited to those with 2-year followup that reported outcomes by gender. Ten articles met inclusion criteria. Study quality was evaluated using the Modified Coleman Methodology Score; the overall quality was poor. Heterogeneity and bias were analyzed using a Mantel-Haenszel statistical method.Women demonstrated an increased odds of developing ALTR (odds ratio [OR], 5.70 [2.71-11.98]; p0.001), dislocation (OR, 3.04 [1.2-7.5], p=0.02), aseptic loosening (OR, 3.18 [2.21-4.58], p0.001), and revision (OR, 2.50 [2.25-2.78], p0.001) after primary MoM HRA.A systematic review of the currently available literature reveals a higher rate of complications (ALTR, dislocation, aseptic loosening, and revision) after MoM HRA in women compared with men. Although femoral head size has been frequently implicated as a prime factor in the higher rate of complication in women, further research is necessary to specifically probe this relationship. Retrospective studies of data available (eg, registry data) should be undertaken, and moving forward studies should report outcomes by gender (particularly complications).Level III, therapeutic study.

W e thank Dr. Wyland and appreciate his interest in our study. We would like to respond to the concerns raised in his letter to the editor [2]. We agree with Dr. Wyland that reporting the outcome in five separate subscales (symptoms; pain; function, daily living; function, sports and recreational activities; quality of life), enhances interpretation. However, as stated by Roos and colleagues [7], even though it makes it impossible to closely monitor the stages of rehabilitation, the calculation of a total KOOS score can show an improvement. Due to the fact that our objective was to report the general patient-relevant outcome at a minimum of 6 months postoperatively (and not to optimize rehabilitation), we decided to report a single score in this initial retrospective case series. Dr. Wyland noted that ‘‘the grading system described by Mitsou et al. and previously by Tegner actually evaluated the success of ACL reconstruction, not knee osteoarthritis treatments.’’ Due to lack of a specific patient-reported outcome score for treatment evaluation of subchondral bone marrow edema lesions, we decided to use the Tegner-Lysholm Score which, as correctly stated by Dr. Wyland, was initially developed and validated for ACL injuries. The rationale behind our decision lies in the fact that in up to 80% of ACL-ruptured knees, bone marrow edema lesions are present [3, 4]. We also feel that the critique by Bengsston and colleagues [1] on the sensitivity of the Tegner Lysholm Score regarding ACL injuries and other lower extremity conditions corroborates as opposed to discredits our choice. The grading of the score allows a more critical analysis of the outcome [1]. Dr. Wyland also correctly noted that ‘‘... there was no discussion of surgical revisions in evaluating clinical failure or surgeon learning curve, which one would expect to influence failure rates.’’ Within the confines of manuscript length, we reported the followup data that was available for this retrospective study; none of the patients had revisions. However, three patients were lost to followup. Also, the minimum followup to be included in this (RE: Chatterjee D, McGee A, Strauss E, Youm T, Jazrawi L. Subchondral calcium phosphate is ineffective for bone marrow edema lesions in adults with advanced osteoarthritis. Clin Orthop Relat Res. 2015;473:2334–2342). Each author certifies that he or she, or a member of his or her immediate family, has no funding or commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request. The opinions expressed are those of the writers, and do not reflect the opinion or policy of CORR or The Association of Bone and Joint Surgeons. D. Chatterjee MD (&), A. McGee MD, E. Strauss MD, T. Youm MD, L. Jazrawi MD Orthopaedic Surgery, NYU Langone Medical Center, 333 East 38th Street 4th Floor, New York, NY 10016, USA e-mail: Dipal.Chatterjee@nyumc.org; dipal.chatterjee@gmail.com Reply to Letter to the Editor Published online: 24 September 2015 The Association of Bone and Joint Surgeons1 2015

To the editor, We read the Level I study by Tarwala and colleagues [11] with great interest. The study compared the operative tourniquet group to cementation tourniquet group in patients undergoing TKA. The authors found no difference in surgical time, postoperative pain, motion of the knee, blood loss, and complications between the two groups. The authors also indicated in their conclusion that they prefer to use the tourniquet only during cementing in TKA. Although the authors mentioned that there were no previous studies comparing the effects of tourniquet used only during cementing, we found two studies on the same topic published before the current study [4, 7]. Kvederas and colleagues [4] compared three groups undergoing TKA in a Level II study. In the first group, the tourniquet was inflated before incision and deflated after hardening of the cement. In the second group, the tourniquet was inflated just prior to cementing and was released after its hardening. In the third group, it was inflated before incision and deflated after closure of the incision. In contrast to Tarwala et al., these authors found higher estimated blood loss with the second group (the group that used the tourniquet only during cementation). The second study by Mittal and colleagues [7] noted higher transfusion rates with the short tourniquet group (cementation tourniquet). The authors had to abandon the study due to unacceptably high transfusion rates in the cementation-only tourniquet group. As both of these studies were not cited by the authors, their findings, which are in contrast to the present study, were not compared in the Discussion section. The authors failed to perform a power analysis at the initiation of the study because similar studies were not available in literature. The timing of deflation of the tourniquet remains unclear in the current study. In the Methods section, it is stated that the tourniquet was released in all patients at the completion of cementation of the patella and the knee held in extension with compression of the patella for the subsequent 10 minutes it took for the cement polymerize. If the tourniquet was released after complete polymerization of the cement, the mean tourniquet time in the cementation tourniquet group of 9 minutes (range = 7 minutes to 14 minutes) is less than the time it took for the cement to polymerize completely. If the tourniquet was released just after implantation, but before complete curing of the cement, blood that would flow after the tourniquet’s deflation would be mixed with cement at the crucial phase of cement polymerization and weaken the interface for cementation. It has been shown that hyperemia following tourniquet deflation peaks at 5 minutes after deflation [5]. Therefore, it would not provide a bloodless bone for cementation, defeating the purpose of using tourniquet only during cementation. Additionally, certain discrepancies were found in the references cited in the text and their actual contribution. In the Introduction, the authors compared randomized controlled trials featuring patients undergoing TKA with or without tourniquet that show no statistical difference in blood loss or less blood loss when no tourniquet is used. The authors provided three additional studies [2, 6, 13] in their References section. However, none of these three papers have studied blood loss with or without tourniquet in TKA. Yang and colleagues [13] investigated the effectiveness and safety of tranexamic acid in reducing postoperative blood loss in TKA, but not of the tourniquet alone. A study by Vandenbussche and colleagues [12] has been quoted as showing no difference or less blood loss without tourniquet. However, the study reports higher blood loss without the use of a tourniquet. Similarly, a study by Kato et al. [3] has been cited as a reference for wound complications following tourniquet use. However, the original study purpose was to detect emboli during the tourniquet inflation phase and to identify the composition of the echogenic material. In the Discussion section, the authors cited two meta-analyses [1, 10] as references for the absence of differences in pain with or without the use of tourniquet. However, both of these articles failed to assess pain as a part of their meta-analysis. Also, no difference in swelling of the knee has been shown as a finding of both these meta-analysis when they have not assessed the same. In fact, both of these studies discussed increased swelling of the extremity with tourniquet use in their Introduction. Alcelik and colleagues used a reference by Silver et al. [8] to cite the increased swelling post-tourniquet use. A study by Tai and colleagues [9] has been mentioned as reference for a study showing that increased drainage has been correlated to tourniquet pressure more than 225-mm of Mercury. However, this study compared the tourniquet and non-tourniquet group with respect to blood loss, soft tissue damage, pain, swelling rehabilitation, and hospital stay. It does not address the correlation between tourniquet pressure and drainage. In fact, Tai et al. [9] did not use a drain in their study in order to avoid excessive blood loss.

We read the letter from Tao et al. with great interest. We very much appreciate their comments. In our study [4], we highlighted the fact that surgical technique is the key to achieve ideal nail positioning, ensure stable fixation, and prevent major complications. We agree with the importance of keeping the instrument insertion line (guide wire, reamer, and the nail) coaxial to the femoral canal line. Following the surgical technique guidance is the safest way to achieve that. In our practice, we always try to use the recommended entry point for the PFNA II according to the manufacturer’s suggested surgical technique; the entry point recommended by Synthes is at the tip of the greater trochanter or slightly lateral to it [6]. The decreased mediolateral angle of the PFNA II (5° compared with 6° for the PFNA) and its flattened lateral surface allow for that slightly more lateral entry point. To date, in our department, the PFNA-II has been used in more than 300 cases of unstable intertrochanteric fractures and no varus reduction of the proximal head-neck fragment or a wedge opening effect between the head-neck fragment and the shaft fragment has occurred. It is true that there are numerous cases where defining the exact position of the awl at the tip of the greater trochanter is not reliable [1, 2]. We agree that potential problems such as a stiff spine, soft tissue mass about the hip, operative drapes, or laterally oriented operating trajectory of the side-standing surgeon could arise, as Tao et al. noted. We still consider the greater trochanter entry point to be adequate for those cases. There also are cases with extension of the fracture line around the tip of the greater trochanter or with substantial comminution at the suggested entry point. In the latter cases we suggest a deeper awl insertion bypassing the fracture line and introduction of the guide wire under careful fluoroscopy in the AP and lateral views. Tao et al., in their letter, are in accordance with Streubel et al. [5] who suggested that the trochanteric tip represents the ideal starting point in only the minority of cases and an entry point 3 mm medial to the tip is the most suitable for the majority of the trochanteric nails. Nevertheless, the above suggestions are contrary not only to the manufacturer’s surgical technique, but also to the pioneering studies that introduced the PFNA II for Asian patients [3, 7]. We do not argue with the experience of Tao et al., as we do not have a medial entry point experience. However, we do stress the fact that the suggested entry point is at the tip of the greater trochanter and this specific approach was used in our published series. We thank Tao et al. for adding their experience. Adherence to the suggested surgical techniques should not discourage surgeons from trying to improve on or question some of details.

The posterior tension band complex, as articulated so clearly by Dr. Yoshihara, in my opinion makes an important contribution to the etiology of proximal junctional kyphosis (PJK). However, my hesitation in attributing the posterior tension band as the most important risk factor is largely owing to the lack of supportive data in the current literature. This lack of data lies partially in the difficulty of measuring the preservation of the posterior structures and lack of consistency with which the data often are presented. For example, if the dissection of the posterior muscular attachments to transverse processes of the upper thoracic vertebrae plays a pivotal role in the development of PJK, studies should consistently show upper instrumented vertebrae of T1–T6 having a higher incidence of PJK [1]. More recent literature comparing PJK rates in those with upper thoracic (T1–T3) versus lower thoracic (T10–T12) instrumented vertebrae [4, 8] have determined that upper instrumented vertebrae in the lower thoracic spine had a higher PJK rate. In addition, some studies [4–8] have failed to show a difference in PJK rates between different upper instrumented vertebrae. The etiology of PJK is clearly multifactorial and therefore, studies should focus on conducting multivariate analyses when identifying risk factors associated with the development of PJK. We did not investigate the posterior soft tissue integrity. As mentioned by Dr. Yoshihara, the difficulty in including this as a risk factor lies in the inability to reliably quantify the extent of soft tissue dissection and facet capsule disruption at the time of the index operation. One point mentioned by Dr. Yoshihara is that pedicle screw instrumentation damages the supraadjacent facet capsule owing to the footprint of the screw head. Although I agree this is theoretically possible, this has not been supported consistently in the literature [2, 4, 7, 10]. If this were true, one would expect constructs using hooks at the upper instrumented vertebrae to have lower rates of PJK. In fact, reports are inconsistent when it comes to instrumentation type at the upper instrumented vertebrae and PJK, with one report [2] showing a difference and others [4, 7, 10] showing no difference whether a pedicle screw or a hook is used at the upper instrumented vertebrae. As our understanding of the etiology of PJK improves, the spectrum of pathologic features encompassing PJK is becoming more transparent. Earlier studies have described PJK to be a pure radiographic finding [1, 6] while more recent studies [4, 5] suggest differences in Scoliosis Research Society outcomes scores between those with and without PJK. In studies such as those referenced by Dr. Yoshihara [2, 3, 9], no differences in health-related quality of life questionnaires were noted between patients with and without PJK and therefore, the amount of increase in PJK angle noted may be of questionable clinical importance (if it is attributed solely to the posterior approach). This shows the necessity in distinguishing purely radiographic PJK versus progressive PJK causing pain versus catastrophic PJK which often can present with myelopathy and spinal cord impingement. Studies that focus on differences between these subsets of patients with PJK will be useful in determining clinically important risk factors since it is entirely plausible that the inclusion of less severe cases of PJK with more severe cases in a study cohort can have an umbrella effect and dilute otherwise important findings. At the recent Hibbs Society Meeting held during the 2012 Annual Scoliosis Research Society Meeting in Chicago, Illinois, USA, a group of surgeons met with interest on the topic of PJK. It is clear that our understanding of PJK has improved since it was first described [1] but much work remains in understanding the cause and optimal method for treating severe cases. I believe these questions will be answered in future studies and will help us tailor methods for the prevention of PJK.

We thank Dr. Moyad for his constructive criticism and service to the Haitian people. His positive experience providing care in the wake of this natural disaster is testament to the power of volunteerism in resource-poor countries. After the earthquake, many medical and surgical volunteers sacrificed to provide the highest quality care to disaster casualties. These stories and tremendous worldwide response should give all of us hope regarding our international capacity for relief. Nevertheless, the intention of the publication was to provide our readership with a perspective that has remained largely elusive. Although many publications regarding the orthopaedic response to the Haiti earthquake document the quantity of procedures performed and the personal stories of the volunteers, there are few systematic documentations of the failures. Our systematic method of data collection and analysis has many weaknesses highlighted in the publication, but it provides an important window into potential ways in which we can improve and devise measures of disaster care. Many of the anecdotes associated with poor-quality care, we believe, were preventable with training. From our interviews, for example, we discovered that ill-prepared physicians such as ophthalmologists and pediatricians were performing orthopaedic surgeries without adequate training. In addition, to address Dr. Moyad’s specific point regarding fasciotomies, there is documentation to suggest that this procedure should be reconsidered in the acute muscle-crush compartment syndromes commonly found in earthquake zones. The muscle in these limbs usually is already dead and in these resource-poor settings, when damage-control orthopaedics is necessary, there is limited time for repeated operations that risk limb-threatening infection [2]. Although we will never know the specific nature of every injury treated, there clearly is room for debate and greater need for better documentation and further study of disaster response. A substantial report from the Pan American Health Organization (PAHO) discusses the overall lack of organization and chaotic pattern of the relief effort [1]. The foreword of the report states that the response, “included a number of wholly unprepared or even incompetent health actors who bypassed the overburdened coordination mechanisms”. For these reasons, the PAHO report highlights the need for accreditation and training in disaster response, a matter about which we disagree with Dr. Moyad. Regardless of the outcome, training courses provide volunteers with the opportunity to share stories, exchange knowledge, build expert opinion, and prepare for a variety of patient-care possibilities. We hope that formal training courses are cultivated to continue to improve the care provided to patients most in need.

We greatly appreciate the letter from Drs. Unglaub, Leclere, Hahn, and Wolfe regarding our article, Peripheral triangular fibrocartilage complex tears cause ulnocarpal instability: a biomechanical pilot study [1]. Regarding the surgically created lesion of the peripheral triangular fibrocartilage, we transected the insertion of the articular disc from the ulnar styloid with a Number 11 scalpel blade. This was done using arthroscopic observation from the 6R portal. Transection of the disc was confirmed during the same arthroscopy by inserting a probe at the base of the styloid. Arthroscopic images showing creation of the tear and confirmation of the tear are shown below (Fig. 1). A video showing the latter is available with the online version of CORR®. Fig. 1A–D Arthroscopic images show (A–B) creation and (C–D) confirmation of tear of the peripheral triangular fibrocartilage.

Drs Wettstein and Mouhsine are correct to point out the benefits of advanced axial imaging for total hip replacement planning. It is especially helpful in assessing the rotational anatomy of the femur and acetabulum which may help individualize the best component alignment. They also are correct to point out that determination of the actual rotational version of the femur requires scanning the distal femur. The purpose of my study [1] was not to determine anteversion of the arthritic hip or postoperative version of the surgically treated hip since such studies have been reported. Rather, the purpose of my study was to compare preoperative version with the final postoperative version in the same patient. The methodology used was a fluoroscopic technique at the time of surgery, the interpretations of which are subjective and therefore the data were checked with a different methodology. Given similar findings, I presumed the study methods were valid. Two MRI series were used, one with a group of patients with no arthritis (scanned for other medical reasons) and another with patients who underwent MRI as part of the planning for hip replacement, which did include the knee, as Wettstein and Mouhsine suggested. Unfortunately, they missed the main point of the study which showed that version of the anatomic femoral head did not predict version of the prosthetic femoral head using a canal filling broach-only bone ingrowth stem. In fact, on average, the total hip femoral head is more anteverted than the native femoral head, 18.9° (femoral head) versus 27.0° (prosthesis). The range of postoperative version was wide, 0° to 42°, so there were outliers with extremes of retroversion and anteversion. This has implications for polyethylene wear and joint stability. Briefly, as the technique is presented in detail in the paper, a neutral femoral position is determined and marked, and the preoperative proximal femur version is compared with the postreplacement proximal femur. The end points for both of these determinations are subjective, based on change in shape of the image, leaving the conclusions open to criticism regarding the validity of the observation. As the shape of the femoral canal determines the position of a canal-filling stem, a comparison of the canal shape (and therefore version) of the neck can be compared with the head, using axial imaging, either CT or MRI, and the neck version should differ from the head version in the same direction if the study methods are valid. Both scan series showed the same findings, namely that the neck version was more than the head version, which would lead to the canal-filling stem having more anteversion on average compared with the femoral head. The magnitude of the differences was interesting: the average difference for the fluoro-surgical series between preoperative and postoperative images was 6.1°, whereas the MRI series differences of 15.4° for the nonarthritic group and 11.2° for the arthritic group were in the same ballpark as that of the surgical group. Therefore, the conclusions of my study were valid, namely that the postoperative femoral stem is, on average, more anteverted than the preoperative femoral head when using a canal-filling broach-only stem, and the surgeon needs to be aware of this fact to keep the appropriate relationship between the acetabulum and femur to avoid impingement and excessive polyethylene wear. The increased use of axial imaging for total hip planning is a good idea because it would indicate when a specialized implant is needed or when a change from routine component placement is warranted.

We thank Dr Fang for his careful review and consideration of our manuscript [1]. For the benefit of patients every debate is welcome in the development of surgical techniques. Dr Fang questioned whether the technique addresses the hindfoot. The technique we describe reduces from the subtalar joint to the medial cuneiform first metatarsal joint. Therefore, the hindfoot also is corrected. As described in the article, the hindfoot of these patients was in valgus preoperatively and was corrected by the technique. We showed the AP and lateral views of the cases so the reader could view the correction we obtained. We have data for the measurements of all patients (data were not shown). Lateral measurements are much more a reflection of the correction with this technique than the AP angles. If the subtalar joint appears corrected on the lateral view, it will be corrected on the AP view and we reported the subtalar joint was adequately corrected. The second concern regarding degeneration of the adjacent joints also deserves our attention. Wunschel [2] suggested degenerative disease would occur in adjacent joints whenever there is a limitation of movement produced by an arthrodesis (although he did not report on such occurrence in his full article) and we agree. Our patients are being followed every 6 months and none has had complaints of pain or any sign of arthritis up to the last followup (ranging from 2.5 to 7.5 years). The transference of pain to the forefoot also was not observed. A study on the followup of our patients in which the issue of arthritic lesions will be addressed is underway. The third observation regarding hardware points out a “too long screw” observed on the lateral radiograph. As described in our paper, no local complications occurred including skin problems. The long screw observed on the image was observed by our team, but we believed it unnecessary to remove as the patient had no complaints. A second intervention to correct the length of a screw can be a bigger problem in an aligned and pain-free foot. One patient had pain in the plantar surface of the foot, in that case bilaterally, and had the plates removed with resolution of the pain (and a corrected deformity). However, we cannot attribute this pain solely to presumed impingement with soft tissues. Regarding the insertions of the tendons, the description of the technique shows that the periosteum was retracted together with the tendon insertions. Clearly, the insertions of the plantar tendons are contiguous with the periosteum and they are replaced after the plates are fixed and the wound is closed. Therefore, tendon function is not impaired by the procedure. In this deformity the posterior tibial tendon usually is not working properly. The details regarding function, such as balance, will be discussed in a followup report of these patients. We are pleased to have the opportunity to further describe details regarding the surgical technique we proposed.

We thank Dr. Koh and colleagues for their well-taken comments to our article, “The Effect of Long-term Alendronate Treatment on Cortical Thickness of the Proximal Femur” [7]. Our results interestingly showed that the majority of patients treated with alendronate at a minimum of 5 years had stable or decreased cortical thickness. This finding is contradictory to the results from Lenart et al. [3]. Although the method used to calculate a cortical thickness ratio from dual energy x-ray absorptiometry images in our study is similar to that of the plain radiographs used by Lenart et al., a so-called normalized cortical thickness, some differences must be underscored between their study and ours regarding the methodology and patient population. First, Lenart et al. [3] reported the normalized cortical thickness in only patients with subtrochanteric fractures, whereas we included only patients without a history of fractures around the lower extremities. Thus, our findings may not be applicable to those with atypical femoral insufficiency fractures. As we discussed in the original article [7], our study strongly supports the concept that patients with atypical femoral insufficiency fractures had thickened femoral cortices at the onset of bisphosphonate therapy. Second, we determined the cortical thickness ratio only at the subtrochanteric region, whereas Lenart et al. [3] measured femoral cortices just distal to the fracture site, which may not always be synonymous with the subtrochanteric area. Thus, the average value of the normalized cortical thickness from their study may differ from ours. Third, the mean ages of patients in their study were much older (70 and 83 years in patients with and without x-ray pattern for atypical femoral insufficiency fracture, respectively) than our patients (62 and 63 years in patients with and without history of long-term bisphosphonate therapy, respectively). It is possible that patients of different ages may respond to alendronate treatment differently. In addition, we do not have rigorous detail available regarding the adherence and compliance of patients with long-term bisphosphonate treatment in our study. However, the bone mineral density responses in our patients with long-term alendronate therapy were consistent with a compliant population based on previous reports [1, 5]. The majority of patients with atypical femoral insufficiency fractures have enlarged femoral cortices. In addition, they also have localized femoral thickening that may represent a true stress fracture [1–3]. We speculate that a stress fracture occurs at an area of abnormal stress concentration, such as at the lateral aspect of the femur attributable to anterolateral femoral bowing. As prolonged bisphosphonate therapy may lead to inhibition of the fracture healing process and deposition of poor-quality bony tissue [4], these stress fractures can propagate to simple transverse or short oblique fractures with beaking. Nevertheless, we agree with Koh and colleagues that the American Society for Bone and Mineral Research criteria [6] to define atypical femoral insufficiency fractures needs further refinement. As we gain a greater understanding of the pathophysiology, we will be able to better define the critical elements of this unique disorder.

We thank Drs. Van Tongel and De Wilde for their interest in and comments regarding our article [1]. In the Methods section, they questioned the following statements: “it is unclear what they mean when they say it is already more lateralized. If they mean the center of rotation, then this is not correct. The center of rotation does not change by enlarging the diameter of the glenosphere.” We wrote: “The disc of cancellous bone graft thickness was adjusted according to the size of the sphere. A 10-mm graft was used for a 36-mm sphere and a 7-mm graft for a 42-mm sphere since it is already more lateralized than the 36 mm.” We refer to the humerus and not the center of rotation. As mentioned by Drs. Van Tongel and De Wilde, using a 10-mm autograft and a 36-mm glenosphere [10 + 18 = 28 mm] or a 7-mm autograft and a 42-mm glenosphere [7 + 21 = 28 mm] leads to the same humeral lateralization. This choice in the surgical technique is based on our experience: using a 42-mm glenosphere and a too-thick autograft (10 or 12 mm, for instance), in a patient without glenoid bone loss might cause difficulty at the time of reducing the humerus, which is dislocated posteriorly for glenoid exposure. Our goal with the BIO-RSA technique is to obtain the same humeral lateralization (28 mm), regardless of the size of the sphere. Drs. Van Tongel and De Wilde also stated that we “did not describe if there was a difference between the prevalence of scapular notching between the group with a 36-mm glenosphere and the group with a 42-mm glenosphere. This would be interesting to know because using a larger hemisphere on the same position of the baseplate means that there is more prosthetic overhang.” In our series, one of the 10 patients (10%) with a 42-mm glenosphere had scapular notching, whereas scapular notching occurred in eight of the 29 patients (28%) with a 36-mm glenosphere. Using Fisher’s Exact Test, we did not find a significant difference in the proportion of patients with notching in the two groups (p = 0.39). This probably is attributable to the small number of patients in our series. Almost three times more notching occurred in our patients with the 36-mm glenosphere. Thus, our observations seem to confirm that when a large glenosphere (42 mm) is used with the same diameter autograft (29 mm), the incidence of inferior scapular notching is less. As mentioned, this construct increases prosthetic overhang and could explain these findings. We agree that prosthetic overhang probably reduces inferior scapular impingement and presumably notching [3, 5]. However, with the numbers available in our series, we were unable to confirm these findings. We hope to confirm your results in a larger series of BIO-RSA in the future. We believe decreasing the risk of inferior scapular notching is not the only benefit of the BIO-RSA [1, 6]. Other problems encountered with the Grammont (medialized) reverse prosthesis are limited shoulder rotation (specifically in internal rotation, with few patients being able to pass their hand in the back), prosthetic instability (more frequent when the prosthesis is implanted through the deltopectoral approach), and loss of shoulder contour [2]. By effectively creating a scapula with a long neck, the BIO-RSA also decreases the rate of anterior, posterior, and superior scapular notching (allowing greater clearance for the humeral cup around the glenoid sphere), and therefore, improving shoulder mobility in elevation, abduction, and external and internal rotation. In addition, by lateralizing the humerus, the BIO-RSA improves shoulder stability (because of improved tension of the deltoid and the remaining cuff) and shoulder contour. Finally, in contrast to metallic increased offset, BIO-RSA offers the advantage of maintaining the joint center of rotation at the prosthesis-glenoid interface, thereby minimizing torque on the glenoid component [4].

The intermix between obstetrics and orthopaedic trauma has been an interest of mine dating back several years. My father is an obstetrician-gynecologist and I spent years working with him. Thus it is natural that I continue research involving pregnancy and orthopaedic trauma. I was thrilled I had the opportunity to work with Dr. Carol Copeland, an expert in this area, during my Trauma Fellowship at the R.A. Cowley Shock Trauma Center. The concept of my collaboration with Dr. Carol Copeland, which began in 2001, focused on pelvic fractures in women of childbearing age and was a direct continuation of her research [2–4]. She developed an extensive questionnaire in 1993 which served as a basis for her articles and our subsequent study. Together, we developed a full research protocol on “Childbirth After Pelvic Fractures”, but I was not able to complete the study during or immediately after my fellowship. I first submitted the “Childbirth After Pelvic Fractures” grant to the Ruth Jackson Orthopaedic Society in 2005. In December 2005, I was notified I did not receive the grant, but they stated there was similar grant by Dr. Vallier and perhaps we should talk. I approached Dr. Vallier, sending her my research protocol, grant proposal, and forms. She agreed to collaborate. I submitted the grant in 2006 successfully to the Foundation for Orthopaedic Trauma ($15,000 received) and the Ruth Jackson Orthopaedic Society/Zimmer Research Grant ($29,948 received). Being the Grant Principle Investigator, I communicated with the other sites’ PIs (Dr. Vallier was the site PI for MetroHealth Medical Center) on numerous occasions, providing extensive details regarding how to complete the study and all spreadsheets and forms to be used. A subcontract was signed with each participating center. As indicated in the article by my coauthor and me published in CORR [1], all patients involved in that study were to be sent the study invitation letter, consent form, HIPAA form, patient information form, SF12, and release form for the obstetrician (as shown in Appendix 1 of the article published in CORR [1]). The study centers then were to send the forms to the obstetrician for completion. In addition, there was an xray and injury form to be completed by the investigators for each patient. I requested the data be sent to me in early January 2009 for submission to the Orthopaedic Trauma Association (OTA). The other two involved centers had extensive data sheets with more than 70 points, as they followed the study protocol. I received a spreadsheet with only 17 data parameters from Dr. Vallier. (Editor’s Note: This spreadsheet was sent to me.) I found it difficult to write an abstract, but did so with the limiting factor being the Metro Health Medical Center data. The abstract was accepted for podium presentation for the 2009 annual meeting of the OTA. More data from Metro Health Medical Center were needed to complete a scholarly paper. On numerous occasions, I asked, through multiple avenues of communication, to obtain the additional data with the intent of including Dr. Vallier as an author for the article published in CORR [1]. Dr. Vallier stated she was not informed the article had been submitted for publication, but I have e-mails confirming otherwise. As I did not receive the complete data from Dr. Vallier, we could not include her patients in the CORR article. In March 2010, I was reviewing a blinded article for the Journal of Orthopaedic Trauma on pelvic injury and its association with sexual dysfunction in women. I was surprised to find a 10-item questionnaire, of which all 10 items were part of my 18-item questionnaire published as Appendix 2 in our article in CORR [1]. The questionnaire Dr. Vallier provided in her article contained the same context and descriptive choices for the 10 items. Dr. Vallier signed a subcontract with the University of Texas Southwestern (where I was completing the research project) indicating in the statement of work that she agreed to complete the study, following our protocol and using the specified forms. In addition, the submission of articles regarding any patients in this study requires permission from the study PI (me) and also acknowledgment of the monies received. Because a grant cannot be submitted without the patient forms and without the collaborating PIs viewing the grant application, the forms in question were received by Dr. Vallier in 2006. That would be more than enough time for Dr. Vallier to let me know that she had the same questions. I questioned her, but she did not provide a direct answer to my question, “How could you have my data sheets since 2006 and not know the questions were the same/quite similar?” I want to thank the editor for the opportunity to provide information regarding this research. These situations can be regretful when completing research to seek the best possible care and information for our patients.

To the Editor We read with great interest the article, ‘‘The Withdrawn ASR™ THA and Hip Resurfacing Systems: How Have Our Patients Fared Over 1 to 6 Years?”, by Hug et al. [5]. We thank them for sharing their results and for their contribution to the knowledge related to the performance of The ASR™. However, in two instances in the Discussion section, Hug et al. state that metal-on-metal devices are flawed or poorly performing as a class. The scope of their study was limited to the ASR™ system and such statements cannot be derived from their results. If they were referring to other publications, references should have been inserted, but none was present. Such statements can be made only after demonstration that all devices from a class are outperformed by all devices from another and such a result is unlikely. In addition, there are at least five recent publications showing Kaplan-Meier survival estimates of metal-on-metal hip resurfacing devices ranging from 94.6% to 99% at 10 years in male patients [2, 4, 6, 7] or patients with large femoral components sizes [1]. If progress is going to be made in the field of hip arthroplasty, is it not time surgeons begin to treat patients as individual cases rather than with a “one device fits all” policy? The revision rates of metal-on-metal devices are design-dependent [3]. The high failure rate, elevated blood metal ion levels, and high prevalence of adverse local tissue reactions observed with the ASR™ prosthesis are unfortunate but do not allow inference to the performance of the bearing technology itself.

To the Editor With great interest we read the article by Johnson et al. regarding the presence of the ACL in patients with arthritic knees [1]. Limitations in function after TKA are common. Because of the increasing need for TKA, it is important to determine the cause of patients’ dissatisfaction. Johnson et al. concentrated on the kinematics of the knee, and more specifically the presence of the ACL preoperatively. They concluded the best way to determine if the ACL is present is to combine MRI with the Lachman test. However, we had some difficulties interpreting the results because Johnson et al. did not mention whether the researchers who performed the observation during the operation were blinded for the results of the Lachman test. If this is not the case, the results possibly are biased and the observed relationships may be overestimated. Furthermore, we question why the Lachman test was performed after induction of anesthesia. It seems more logical and clinically relevant to perform this test at the outpatient clinic before surgery so that the surgeon can choose the right implants and instruments in advance. Johnson et al. assessed preoperative MRIs from 100 of the 200 included patients. It is unclear why and on what basis the authors’ selection of 100 of the total of 200 included patients was made. Was this a representative selection? In the Results section, part of the answer to the 5th question (did ACL status depend on age or sex?) is missing. Does the ACL status depend on sex? Unfortunately it is only reported that patients with an intact ACL at the time of surgery were older. Finally, there are inconsistencies and missing data in Table 1. The number of patients with absent intraoperative ACL integrity is missing. In the same table we found that the 194 negative Lachman tests should be 184 to make a total of 100%. We would appreciate the authors’ responses to our questions.

I thank Dr. Mehin for his comments regarding our paper [2] describing the use of a morphometric grid to quantify osteolysis seen on radiographs. I agree with him regarding the importance of the location and size of retroacetabular osteolytic lesions in the assessment of a THA. The availability of a simple and reliable tool to quantify these lesions is important for long-term THA surveillance and also can be useful to explain to asymptomatic patients the significance of radiographic changes. Further research with the morphometric grid may help to describe the extent of osteolysis, which predicts instability of an acetabular component. This, along with other work including that of Dr. Mehin and his colleagues [1], will contribute to the decision-making process for revision hip surgery.

I read with interest the letter from Mr. McClure and Dr. Heeckt in reference to our recent article [1], and acknowledge the limitations of joint registry data when evaluating the value to be gained from newer (and inevitably) more expensive designs. Indeed, some of the concerns raised by Mr. McClure and Dr. Heeckt are inherent in any implant/explant registry such as the HEJR and may serve as either limitations or strengths, depending on one’s point of view. Selection bias was not controlled, and certainly activity level or rehabilitation potential is not captured in most implant/explant registry databases. However, age as a crude proxy for activity level was adjusted for as a confounder in the Cox regression analysis, as noted in the article. The fact that different surgeons select different implants for different patients for different reasons is exactly what makes analysis of these types of data so valuable; it mirrors the practice of orthopaedic surgery in a community setting. Similarly, the critique of surgeon volume as another potential contributor to device longevity, although accurate, may not reflect the current reality of arthroplasty practice in North America. Mr. McClure and Dr. Heeckt point out that a “full economic cost analysis” would be more appropriate to assess the value of newer devices, and we fully agree. However, as we pointed out in the limitations section of the Discussion, an implant/explant registry database cannot provide that information. We disagree that the “premium implants” discussed in our article are implanted with instruments or techniques that are substantially different from the standard implants referenced, or that the former is somehow “fast, safe, simple, and flexible” compared with the latter. All innovation is not progress in the right direction, as the field of arthroplasty surgery has shown time and again. If Mr. McClure and Dr. Heeckt actually believe that “innovation inexorably adds to cost”, then I fear for innovation in our present global healthcare setting. Finally, we previously reported (and referenced in our article) our 94% capture rate for followup, similar to the Scandinavian registries. Although this is a limitation for all such registries, this presumably would affect the premium and standard device recipients in a similar distribution, as we noted in the Discussion. We thank Mr. McClure and Dr. Heeckt for their thoughtful review of our paper, agree with their conclusion that “assessment of value in healthcare is a very complex task”, and hope that the article has added to the debate in some small way.

Reply: I thank Dr. Bauer and appreciate his interest in our case report, “Fibroxanthoma: A Complication of a Biodegradable Screw”, published in a recent issue of the journal [7]. Most of his concerns were raised by the referees during the editorial process. I disagree with his statement that the term, fibroxanthoma, is misleading. Various synonyms have been used in the literature for fibroxanthoma such as fibrous histiocytoma [3], xanthofibroma [1, 2], nonossifying fibroma, fibrous cortical defect [8], and benign fibrous histiocytoma [6]. Use of these various terms stem from authors’ disagreements regarding the histiogenesis. Although considered by some as nonneoplastic, others believe it is a neoplastic process, and yet others think of it as a reactive process [1–3]. Second, Dr. Bauer states that we described a soft tissue swelling at the site of the tibial tunnel but that is not what we described. Rather, we observed and described a slowly progressive, painful, bony swelling (1 × 1.5 cm) at the site of the tibial tunnel. Our initial clinical impression was an ectopic bone formation, delayed allergic reaction to a screw, or disengagement and backing out of a screw. Surgery was performed with the intent to curettage the new bone and/or debride the backed-out screw. At surgery, the macroscopic appearance was that of obliteration of the tibial entry portal, and irregular thickening of the cortex around it gave the impression of a periosteal reaction to the screw. Excision and thorough curettage of the abnormal bone and debridement of the tibial tunnel with a rongeur were done. I agree with Dr. Bauer that correct diagnosis requires a correlation between clinical and histologic findings. A biopsy report of a progressively painful bony mass localized at the entry site and obliterating the tibial tunnel initially was surprising. However, the histopathologic finding of large areas of foam cells interspersed with fibrovascular septations, which were negative for S-100 and positive for anti-human macrophage marker HAM-56, was consistent with the diagnosis of a fibroxanthoma [4, 5]. Finally, I thank Dr. Bauer for providing details regarding the mechanism of degradable orthopaedic devices.

Reply: We appreciate the interest by Huang et al. in our article [1] and the opportunity to reply. The first concern of Dr. Huang and his colleagues regarded the patients we examined in our study population. They correctly note that supination-external rotation injuries do not always have syndesmotic involvement. In our case population, as noted in the article [1], all patients had a positive radiographic stress examination and preoperative MRI that confirmed syndesmotic involvement necessitating fixation. Their second point was whether our posterior malleolar fixation would provide sufficient stabilization for fractures with “greater instability.” We did not address this directly, but as we did mention, the posterior malleolus alone accounts for 42% of the strength of the syndesmosis [2]. We believe that if the medial side is reconstructed, either by fixation of a medial malleolar fracture or by repair of a torn deltoid ligament, additional syndesmotic fixation is unnecessary, even in more unstable injury patterns. Since reviewing the patients in our article [1], the senior author (DGL) has completely stopped augmenting posterior malleolar fixation with syndesmotic screws, even in fracture-dislocations. Each of these patients has stress testing after fixation and they no longer have any sign of instability. Thus, they have anatomic fixation without screws across the syndesmosis. The third question also addresses this topic, asking why a combination of posterior malleolar fixation and transsyndesmotic screw fixation was used in the more unstable fracture-dislocations. During the time we were accumulating this series of patients, we were unsure if the construct would be stable enough for these more severe injuries, but after this study and its predecessors were published and after review of our subsequent patient series (as yet unpublished), we do not believe more severe injuries need supplemental syndesmotic fixation. We thank Dr. Huang and his colleagues for their interest in our article.

We agree with the comments made by Dr. Gallo. The literature relating to this prosthesis is contradictory, with significant variation in the rates of implant survival, periacetabular osteolysis, and polyethylene wear. Numerous reports mirror Dr. Gallo’s experience of poor outcomes with this implant. Unfortunately we cannot offer additional insight regarding reasons why our results are better than those previously published. There is increasing evidence in relation to hard bearing surfaces that surgical technique and correct cup placement are more important than previously thought [1, 3]. It seems likely that these factors plus cup diameter/polyethylene thickness and polyethylene quality also will influence outcomes in other prostheses using conventional bearings. Recently Gallo et al. [2] suggested the position of the cup relative to Kohler’s line, increasing abduction angle of the cup, traumatic and inflammatory arthritis as a primary diagnosis, and patient weight all influence the rate of wear of the ABG I cup. Unlike that study, we did not see any relationship between cup abduction angle and polyethylene wear and unfortunately were unable to record these other determinants for our patient population. We also were unable to determine either the polyethylene thicknesses or the self lives and manufacturing batches of the polyethylene used in our series that may have been a marker of polyethylene quality. There is wide variation in reported details for surgical technique, surgeon numbers, bearing materials, and cup position for the ABG I. Missing information and the heterogeneity for the reports make it difficult to draw any direct comparison between series. What remains clear, however, is that the patients in whom an ABG I prosthesis has been implanted should continue to be closely monitored.