Does the Rule of Thirds Adequately Detect Deficient and Excessive Acetabular Coverage?

BACKGROUND: Assessment of AP acetabular coverage is crucial for choosing the right surgery indication and for obtaining a good outcome after hip-preserving surgery. The quantification of anterior and posterior coverage is challenging and requires either other conventional projections, CT, MRI, or special measurement software, which is cumbersome, not widely available and implies additional radiation. We introduce the "rule of thirds" as a promising alternative to provide a more applicable and easy method to detect an excessive or deficient AP coverage. This method attributes the intersection point of the anterior (posterior) wall to thirds of the femoral head radius (diameter), the medial third suggesting deficient and the lateral third excessive coverage. QUESTION/PURPOSE: What is the validity (area under the curve [AUC], sensitivity, specificity, positive/negative likelihood ratios [LR(+)/LR(-)], positive/negative predictive values [PPV, NPV]) for the rule of thirds to detect (1) excessive and (2) deficient anterior and posterior coverages compared with previously established radiographic values of under-/overcoverage using Hip2Norm as the gold standard? METHODS: We retrospectively evaluated all consecutive patients between 2003 and 2015 from our institutional database who were referred to our hospital for hip pain and were potentially eligible for joint-preserving hip surgery. We divided the study group into six specific subgroups based on the respective acetabular pathomorphology to cover the entire range of anterior and posterior femoral coverage (dysplasia, overcoverage, severe overcoverage, excessive acetabular anteversion, acetabular retroversion, total acetabular retroversion). From this patient cohort, 161 hips were randomly selected for analysis. Anterior and posterior coverage was determined with Hip2Norm, a validated computer software program for evaluating acetabular morphology. The anterior and posterior wall indices were measured on standardized AP pelvis radiographs, and the rule of thirds was applied by one observer. RESULTS: The detection of excessive anterior and posterior acetabular wall using the rule of thirds revealed an AUC of 0.945 and 0.933, respectively. Also the detection of a deficient anterior and posterior acetabular wall by applying the rule of thirds revealed an AUC of 0.962 and 0.876, respectively. For both excessive and deficient anterior and posterior acetabular coverage, we found high specificities and PPVs but low sensitivities and NPVs. CONCLUSION: We found a high probability for an excessive (deficient) acetabular wall when this intersection point lies in the lateral (medial) third, which would qualify for surgical correction. On the other hand, if this point is not in the lateral (medial) third, an excessive (deficient) acetabular wall cannot be categorically excluded. Thus, the rule of thirds is very specific but not as sensitive as we had expected. LEVEL OF EVIDENCE: Level II, diagnostic study.

Proximal Femoral Rotational Osteotomy for Symptomatic Femoral Retroversion†:†A Case Report.

The Rotational osteotomy for femoral retroversion has been extremely rare despite the known association between femoral neck retroversion, hip pain, and osteoarthritis. Here, we describe a case of femoral neck retroversion for which proximal femoral rotation osteotomy. A 16-year-old boy with a past history of developmental dysplasia of the both hip treated conservatively presented with a complaint of pain in left hips. On physical examination, flexion of the left hip was limited to 90° with terminal pain. Internal rotation was also limited to 10°. Computed tomography (CT) showed -7.1° anteversion of the left femur. We performed rotational osteotomy to increase femoral anteversion because conservative treatment was not effective. The postoperative course was uneventful. At 12 postoperative months, his left hip pain was completely disappeared and femoral anteversion was 34° on CT scans. Retroversion of the femur is a distinct dynamic factor that should be considered in the evaluation of mechanical causes of hip pain. Restoring the normal rotational alignment of the hip resulted in cure of the impingement due to femoral retroversion. J. Med. Invest. 67 : 214-216, February, 2020.

Medial closing wedge high tibial osteotomy for valgus tibial deformities: good clinical results and survival with a mean 4.5 years of follow-up in 113 patients.

PURPOSE: A varus-producing medial closing wedge high tibial osteotomy (MCWHTO) is an uncommon procedure. The aim of this retrospective study was to assess the survivorship and prevalence of post-operative subjective knee laxity and satisfaction in a large cohort of patients with a MCWHTO performed without a MCL-reefing procedure. METHODS: All patients (n = 176) who underwent a MCWHTO in our clinic between 2008 and 2016 were approached to participate. After review of patient charts, questionnaires were sent to willingly patients. Primary outcome was the survivorship of the MCWHTO; secondary outcome was patient-reported instability and satisfaction. RESULTS: One-hundred and thirteen patients participated in the study. The 5-year survival rate of the MCWHTO was almost 80%. A total of 77% of the patients was satisfied with the treatment. With regard to post-operative subjective knee laxity, 26% of the patients experienced instability of the knee post-operation. Instability was significantly correlated with the KOOS domains, the Lysholm score, the IKDC knee function score and the Physical and Mental Health Domains of the SF-36. CONCLUSION: Medial closing wedge high tibial osteotomy provides good results regarding survivorship and patient satisfaction for patients with a valgus deformity which is located in the proximal tibia. Clinically relevant is that in the surgical technique without MCL-reefplasty instability is significantly correlated with worse patient-reported outcome measures. The addition of a MCL reefing procedure will improve outcome in selected patients. LEVEL OF EVIDENCE: III.

Medial femoral epicondyle upsliding osteotomy with posterior stabilized arthroplasty provided good clinical outcomes such as constrained arthroplasty in primary total knee arthroplasty with severe valgus deformity.

PURPOSE: A modified technique referred to as a medial femoral epicondyle upsliding osteotomy was proposed to address severe valgus deformity with unconstrained posterior stabilized (PS) arthroplasty. The study compared the effectiveness of the technique and PS arthroplasty with constrained arthroplasty during primary total knee arthroplasty (TKA). METHODS: Fifty-three patients presenting with valgus knees with a mean valgus angle (VA) greater than 30° were prospectively randomized and divided into two groups, and both groups received primary TKA. Upsliding osteotomy with PS arthroplasty was performed on the knees of 27 patients (group A), while the remaining 26 patients (group B) received a constrained arthroplasty. The Knee Society function score (KSF), Hospital for Special Surgery knee score (HSS), range of motion (ROM), mediolateral stability and hospitalization expenses were recorded. The hip-knee-ankle angle (HKA), femorotibial angle (FTA) and VA were analysed. Complications were also recorded. RESULTS: The patients received follow-up care for more than 50 months. The postoperative KSF, HSS and ROM showed marked improvement in both groups (p < 0.05). Radiological assessments showed that HKA, FTA and VA for group A were restored to (179.9 ± 3.0)°, (173.0 ± 2.4)° and (7.0 ± 2.4)°, respectively. For group B, the HKA, FTA and VA were restored to (181.5 ± 2.3)°, (172.5 ± 2.3)° and (7.5 ± 2.3)°, respectively. Only two patients from group A demonstrated mild medial laxity in their knees, and the remaining patients from both groups were stable medially and laterally. However, the total hospitalization expenses and material expenses of group A were less than those of group B because of the more expensive constrained prosthesis and stems. No late-onset loosening or recurrent valgus deformity was displayed. CONCLUSIONS: Both medial femoral epicondyle upsliding osteotomy with PS arthroplasty and constrained arthroplasty showed good outcomes for the restoration of neutral limb alignment and soft tissue balance, which are demonstrated to be safe and effective techniques for correcting severely valgus knees. Therefore, the clinically important finding of this study is that medial femoral epicondyle upsliding osteotomy with PS arthroplasty can be an alternative method for correcting severe valgus knees. LEVEL OF EVIDENCE: II.

Under-corrected knees do not fail more than aligned knees at 8 years in fixed severe valgus total knee replacement.

PURPOSES: A fixed severe valgus knee is a surgical challenge. A safe post-operative Hip-Knee-Ankle angle (HKA) range of 180° ± 4 was recommended, but recent studies mentioned equal results from outliers of this range. Nevertheless, no distinction was made between varus and valgus knees, as well as over-corrected or under-corrected knees. Did post-operative nonaligned total knee replacements (TKR) from fixed severe valgus knees behave differently from the properly aligned population? Did over-corrected knees behave differently from under-corrected knees? METHODS: Through a multi-center retrospective cohort study, we provided 557 knees of at least 10° of minimal pre-operative valgus; in this population 75 presented a post-operative Hip-Knee-Ankle angle (HKA) outside of the 180° ± 4 range; 23 of them had at least 5° of varus; 52 of them had at least 5° of valgus. Median pre-operative HKA of the entire cohort was 194° (range 190-198). Median follow-up was 8 years (range 5-11); Knee Society Score (KSS) results, HKA, Femoral and Tibial Mechanical Angles (FMA, TMA) and complication rates were obtained. The outlier group (HKA ≤ 175 or ≥ 185) was compared to the control group (HKA 180 ± 4); over-corrected (HKA ≤ 175) and under-corrected (HKA ≥ 185) sub-groups were individually tested against the control group. RESULTS: The outlier group had a lower Final Knee Score than the aligned group (p = 0.023). In the over-corrected sub-group, median post-operative FMA was 88° (SD 4°) and median TMA was 87° (SD 4°). The complication rate was higher (p = 0.019). Knee (p = 0.018), Function (p = 0.034) and Final Knee Scores (p = 0.03) were statistically lower than in the control group. In the under-corrected sub-group, mean post-operative FMA was 93° (SD 2°) and mean TMA was 91° (SD 2°). The complication rate was lower (p = 0.019) and there was no difference with the control group concerning KSS. CONCLUSIONS: In case of pre-operative fixed severe valgus knee, one should avoid over-correcting HKA angle and especially the TMA. Over-correction of a severe preoperative valgus in a post-operative varus was prejudicial for TKA survival. Keeping a severe valgus knee in low valgus to avoid using a more constrained implant and/or ligament releases will not decrease the 5-10 year implant survival and functional scores. LEVEL OF EVIDENCE: Level IV-Case series.

Should Acetabular Retroversion Be Treated Arthroscopically? A Systematic Review of Open Versus Arthroscopic Techniques.

PURPOSE: To compare patient-reported outcomes, progression of radiographic arthritis, revision rates, and complications for hips with acetabular retroversion treated by open versus arthroscopic methods. METHODS: The PubMed and EMBASE databases were searched in August 2016 for literature on the open and arthroscopic techniques using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) method. All studies published in the English language that focused on the surgical treatment of femoroacetabular impingement caused by retroversion were included. All arthroscopic procedures, such as acetabuloplasty and labral repair, and open procedures, including anteverting periacetabular osteotomy and surgical dislocation with osteoplasty, were included. Articles that did not describe how retroversion was defined were excluded, as were studies with less than 6 months' follow-up and fewer than 5 patients. Two authors screened the results and selected articles for this review based on the inclusion and exclusion criteria. All results were scored using the Methodological Index for Non-randomized Studies (MINORS) criteria. RESULTS: There were 386 results returned and 15 articles that met the inclusion criteria of this study. Among the studies, 11 reviewed arthroscopic techniques and 4 reviewed open surgical procedures. Both techniques yield good results based on patient-reported outcomes with minimal progression of osteoarthritis and low complication rates. CONCLUSIONS: This review showed statistically and clinically significant improvements for the treatment of acetabular retroversion based on patient-reported outcomes, with low progression of radiographic arthritis, revision rates, and complications using both open and arthroscopic methods. LEVEL OF EVIDENCE: Level IV, systematic review of Level I to IV studies.

Posterior glenoid bone grafting in total shoulder arthroplasty for osteoarthritis with severe posterior glenoid wear.

BACKGROUND: Total shoulder arthroplasty (TSA) in cases with posterior wear can be addressed by eccentric reaming of the anterior glenoid or by augmenting the posterior glenoid with bone grafting or augmented glenoid implants. We report the results of TSA with posterior glenoid bone grafting (PGBG) with humeral head autograft in patients with shoulder osteoarthritis and severe posterior glenoid wear. METHODS: A retrospective review of cases from 2004 to 2014 revealed 34 patients. Preoperative and postoperative radiographs were evaluated for glenoid version and humeral head subluxation as well as component loosening. Patient-reported outcomes were compared preoperatively and postoperatively. Complications and reoperations were also evaluated. RESULTS: Of the 34 patients, 28 (82.4%) were available at a minimum of 2 years' follow-up. PGBG corrected glenoid retroversion from -28° ± 4° preoperatively to -4° ± 2° (P < .001). Humeral head subluxation also improved after PGBG with respect to the scapular axis and to the midglenoid face (P < .001). Radiographic analysis revealed all PGBGs had incorporated. Radiographically, 3 patients (10.7%) had a total of 5 broken or displaced screws. In addition, 3 patients (10.7%) had a broken metal marker in the center peg of the glenoid component. No patients required component revision surgery by final follow-up. Only 1 reoperation occurred for capsular release. Patients showed significant improvements in all patient-reported outcomes. CONCLUSION: Patients undergoing primary TSA with humeral head autograft PGBG showed significant improvements in glenoid version, humeral head subluxation, patient-reported outcomes, and range of motion at an average of 4 years' follow-up. There was a low revision rate and a high rate of graft incorporation.

Periacetabular Osteotomy Provides Higher Survivorship Than Rim Trimming for Acetabular Retroversion.

BACKGROUND: Acetabular retroversion can cause impaction-type femoroacetabular impingement leading to hip pain and osteoarthritis. It can be treated by anteverting periacetabular osteotomy (PAO) or acetabular rim trimming with refixation of the labrum. There is increasing evidence that acetabular retroversion is a rotational abnormality of the entire hemipelvis and not a focal overgrowth of the anterior acetabular wall, which favors an anteverting PAO. However, it is unknown if this larger procedure would be beneficial in terms of survivorship and Merle d'Aubigné scores in a midterm followup compared with rim trimming. QUESTIONS/PURPOSES: We asked if anteverting PAO results in increased survivorship of the hip compared with rim trimming through a surgical hip dislocation in patients with symptomatic acetabular retroversion. METHODS: We performed a retrospective, comparative study evaluating the midterm survivorship of two matched patient groups with symptomatic acetabular retroversion undergoing either anteverting PAO or acetabular rim trimming through a surgical hip dislocation. Acetabular retroversion was defined by a concomitantly present positive crossover, posterior wall, and ischial spine sign. A total of 279 hips underwent a surgical intervention for acetabular retroversion at our center between 1997 and 2012 (166 periacetabular osteotomies, 113 rim trimmings through surgical hip dislocation). A total of 99 patients (60%) were excluded from the PAO group and 56 patients (50%) from the rim trimming group because they had any of several prespecified conditions (eg, dysplasia or pediatric conditions 61 [37%] for the PAO group and two [2%] for the rim trimming group), matching (10 [6%]/10 [9%] hips), deficient records (10 [6%]/13 [12%] hips), or the patient declined or was lost to followup (18 [11%]/31 [27%] hips). This left 67 hips (57 patients) that underwent anteverting PAO and 57 hips (52 patients) that had acetabular rim trimming. The two groups did not differ in terms of age, sex, body mass index, preoperative ROM, preoperative Merle d'Aubigné-Postel score, radiographic morphology of the acetabulum (except total and anterior acetabular coverage), alpha angle, Tönnis grade of osteoarthritis, and labral and chondral lesions on the preoperative MRI. During the period in question, we generally performed PAO from 1997 to 2003. With the availability of surgical hip dislocation and labral refixation, we generally performed rim trimming from 2004 to 2010. With growing knowledge of the underlying pathomorphology, anteverting PAOs became more common again around 2007 to 2008. A minimum followup of 2 years was required for this study. Failures were included at any time. The median followup for the anteverting PAO group was 9.5 years (range, 2-17.4 years) and 6.8 years (range, 2.2-10.5 years) for the rim trimming group (p < 0.001). Kaplan-Meier survivorship analysis was performed using the following endpoints at 5 and 10 years: THA, radiographic progression of osteoarthritis by one Tönnis grade, and/or Merle d'Aubigné-Postel score < 15 points. RESULTS: Although the 5-year survivorship of the two groups was not different with the numbers available (86% [95% confidence interval {CI}, 76%-94%] for anteverting PAO versus 86% [95% CI, 76%-96%] for acetabular rim trimming), we found increased survivorship at 10 years in hips undergoing anteverting PAO for acetabular retroversion (79% [95% CI, 68%-90%]) compared with acetabular rim trimming (23% [95% CI, 6%-40%]) at 10 years (p < 0.001). The drop in the survivorship curve for the acetabular rim trimming through surgical hip dislocation group started at Year 6. The main reason for failure was a decreased Merle d'Aubigné score. CONCLUSIONS: Anteverting PAO may be the more appropriate treatment for hips with substantial acetabular retroversion. This may be the result of reduction of an already smaller lunate surface of hips with acetabular retroversion through rim trimming. However, rim trimming may still benefit hips with acetabular retroversion in which only one or two of the three signs are positive. Future randomized studies should compare these treatments. LEVEL OF EVIDENCE: Level III, therapeutic study.

Humeral Retroversion in Children with Shoulder Internal Rotation Contractures Secondary to Upper-Trunk Neonatal Brachial Plexus Palsy.

BACKGROUND: The most common sequela of neonatal brachial plexus palsy is an internal rotation contracture of the shoulder that impairs function and leads to skeletal deformation of the glenohumeral joint. Treatment options include release, transfers, and humeral osteotomy, all ultimately striving for better function through increased external rotation. Prior studies have shown that neonatal brachial plexus palsy alters humeral retroversion but with conflicting findings. We studied retroversion in children with internal rotation contractures from neonatal brachial plexus palsy to clarify its effect on version and surgical planning. METHODS: Bilateral shoulder and elbow magnetic resonance imaging scans of 21 children with neonatal brachial plexus palsy were retrospectively analyzed. Retroversion referenced to the transepicondylar line at the elbow was measured with respect to 2 different proximal reference axes, the longest diameter of an axial cut of the proximal part of the humerus (the skew axis) and the line perpendicular to the articular surface (the humeral center line). Glenoid version and glenohumeral morphology type (concentric glenoid, posterior-concentric glenoid, biconcave, or pseudoglenoid) were also determined. All geometric variables were assessed for correlation with patient age and the severity of the internal rotation contracture. RESULTS: Retroversion on the involved side was decreased at 6° compared with 19° (p = 0.003), as measured between the skew axis and transepicondylar line. Retroversion referenced to the humeral center line was also decreased at -2° (anteversion) compared with 20° (p < 0.001). Patient age was inversely correlated with retroversion, but was only significant for the skew axis (r = -0.497, p = 0.022), decreasing in linear regression by 2.4° per year (p = 0.038). Humeral retroversion did not correlate with the severity of the internal rotation contracture, glenoid version, or glenoid morphology type. CONCLUSIONS: Humeral retroversion is likely to be less on the affected side in children with internal rotation contractures from upper trunk neonatal brachial plexus palsy and merits consideration in surgical planning. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Total shoulder arthroplasty using trabecular metal augments to address glenoid retroversion: the preliminary result of 10 patients with minimum 2-year follow-up.

BACKGROUND: Options to address glenoid retroversion include eccentric reaming, bone grafting, modifications to component shape, and reverse shoulder arthroplasty. Trabecular metal (TM) augments have been used extensively in the hip and knee to address bone deficiency in arthroplasty as part of a hybrid combination of high-density polyethylene, polymethyl methacrylate, and TM. This study presents the initial results of the use of specifically designed augments in the shoulder to address glenoid retroversion as part of total shoulder arthroplasty (TSA). MATERIALS: Ten patients (4 women and 6 men; aged 60 to 79 years) with Walch grade B2 or C glenoids have undergone TM glenoid augment insertion as part of a TSA, with a longer than 24-month follow-up. Patients received a 15° or 30° TM wedge to correct excessive glenoid retroversion before the glenoid component was cemented. Outcome analysis was performed preoperatively, at 3, 6, and 12 months, and yearly thereafter. RESULTS: All patients have been satisfied, and all scores have improved. There have been no complications and no hardware failures or displacement. All glenoid components were implanted to within 10° of neutral glenoid version. Radiographs at 24 months show good incorporation of the TM augment and the glenoid component. CONCLUSIONS: The TM augments have the advantage of immediate secure fixation, no tendency to collapse, and the ability to correct retroversion of 25° or more. This study confirms the successful short-term outcome of wedge-shaped TM augments to correct glenoid retroversion as part of TSA.

Posterior augmented glenoid implants require less bone removal and generate lower stresses: a finite element analysis.

HYPOTHESIS: Glenoid retroversion can be corrected with standard glenoid implants after anterior-side asymmetric reaming or by using posterior augmented glenoid implants with built-in corrections. The purpose of this study was to compare 2 augmented glenoid designs with a standard glenoid design, measure the amount of bone removed, and compute the stresses generated in the cement and bone. METHODS: Finite element models of 3 arthritic scapulae with varying severities of posterior glenoid wear were each implanted with 4 different implant configurations: standard glenoid implant in neutral alignment with asymmetric reaming, standard glenoid implant in retroversion, glenoid implant augmented with a posterior wedge in neutral alignment, and glenoid implant augmented with a posterior step in neutral alignment. The volume of cortical and cancellous bone removed and the percentage of implant back surface supported by cortical bone were measured. Stresses and strains in the implant, cement, and glenoid bone were computed. RESULTS: Asymmetric reaming for the standard implant in neutral version required the most bone removal, resulted in the lowest percentage of back surface supported by cortical bone, and generated strain levels that risked damage to the most bone volume. The wedged implant removed less bone, had a significantly greater percentage of the back surface supported by cortical bone, and generated strain levels that risked damage to significantly less bone volume. CONCLUSIONS: The wedged glenoid implants appear to have various advantages over the standard implant for the correction of retroversion. LEVEL OF EVIDENCE: Basic Science Study; Computer Modeling.

Effect of femoral anteversion on clinical outcomes after hip arthroscopy.

PURPOSE: To compare the clinical outcomes after hip arthroscopy of patients with femoral retroversion, normal femoral version, and excessive femoral anteversion. METHODS: Patients who underwent primary hip arthroscopy from August 2008 to April 2011 and underwent femoral anteversion measurement by magnetic resonance imaging/magnetic resonance arthrogram were included. The patients were divided into 3 groups: retroversion, normal version, and excessive anteversion. The normal-version group was considered to have a value within 1 SD of the mean femoral version value. Four patient-reported outcome scores and the visual analog pain score were prospectively collected with analysis performed retrospectively. RESULTS: Two hundred seventy-eight patients met the inclusion criteria. Among these patients, mean anteversion was 8.2° ± 9.3°, creating a retroversion group defined as -2° or less and an anteversion group defined as 18° or greater. There were 25 patients in the retroversion group, 219 in the normal-version group, and 34 in the excessive-anteversion group. Most labral tears were noted in the 12- to 2-o'clock range, with the main difference at the anterior 3-o'clock position, where the excessive-anteversion group showed a lower incidence of tearing (30%) than the retroversion group (73%) and normal-anteversion group (78%). Postoperatively, there was a statistically significant improvement from preoperative scores in all 3 groups and for all scores (P < .001). When the postoperative scores were compared for the 3 groups, although all scores were higher in the retroversion group than in the other 2 groups, this was not statistically significant and there were no significant differences in scores among the 3 groups (modified Harris Hip Score, P = .104; Non-Arthritic Hip Score, P = .177; Hip Outcome Score-Activities of Daily Living, P = .152; Hip Outcome Score-Sport-Specific Subscale, P = .276; visual analog scale score, P = .508). CONCLUSIONS: On the basis of patient-reported outcome scores without accounting for diagnoses and treatments, the amount of femoral anteversion does not appear to affect the clinical outcomes after hip arthroscopy. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Correction of acquired glenoid bone loss in osteoarthritis with a standard versus an augmented glenoid component.

BACKGROUND: The magnitude and anatomic consequences of pathologic acquired glenoid retroversion and posterior bone loss that can be surgically corrected with a standard versus an augmented glenoid component have not been studied extensively in a surgical patient population. MATERIALS AND METHODS: Twenty-nine patients with glenohumeral osteoarthritis, acquired posterior bone loss, and increased retroversion were studied by use of a three-dimensional computer surgical simulation. For each case, amount of medialization was measured as the linear distance from the lateral aspect of the glenoid vault model to the center of the articular implant surface. Simulation of implant placement at 0° or 6° was performed with use of a standard glenoid having a uniform thickness and an asymmetric thickness augmented component. RESULTS: An increased amount of medialization was seen with the standard glenoid, 8.3 ± 4.1 mm, compared with 3.8 ± 3.3 mm with use of the augmented glenoid implant (P < .001). When glenoid retroversion was corrected to 0°, pathologic version was shown to have strong and significant relationship to the amount of medialization for both the standard (R(2) = 0.825) and augmented (R(2) = -0.68) glenoid implant. There was an increased ability to correct greater amounts of pathologic version with less medialization by use of an augmented step glenoid compared with a standard anchor peg glenoid. DISCUSSION: Correction of moderate to severe glenoid retroversion by asymmetric reaming cannot always be done with use of a standard component, and if it is done, it will result in greater medialization of the joint line. Use of an augmented component can allow complete correction of retroversion and minimize the effect of medialization.

Guidelines for the selection of optimal glenoid augment size for moderate to severe glenohumeral osteoarthritis.

BACKGROUND: Total shoulder arthroplasty is technically demanding in regard to implantation of the glenoid component, especially in the setting of increased glenoid deformity and posterior glenoid wear. Augmented glenoid implants are an important and innovative option; however, there is little evidence accessible to surgeons to guide in the selection of the appropriate size augmented glenoid. METHODS: Solid computer models of commercially available augmented glenoid components (+3, +5, +7) contained within the software allowed placement of the best fit glenoid component within the three-dimensional reconstruct of each patient's scapula. Peg perforation, amount of bone reamed, and amount of medialization were recorded for each augment size. RESULTS: There was strong correlation between the medialization of the joint line and the glenoid retroversion for each augmented component at neutral correction and correction to 6° of retroversion. At neutral, the range of retroversion that restored the anatomic joint line was -3° to -17° with use of the +3 augmented glenoid, -5° to -24° with the +5 augmented glenoid, and -9° to -31° with the +7 augmented glenoid. At 6° of retroversion, the range of retroversion that restored the anatomic joint line was -4° to -21° with use of the +3 augmented glenoid, -7° to -27° with the +5 augmented glenoid, and -9° to -34° with the +7 augmented glenoid. CONCLUSIONS: There was a strong correlation between glenoid retroversion and medialization for all augment sizes, supporting the recommendation for glenoid retroversion as the primary guide in selecting the amount of augmentation.

Unconstrained arthroplasty in type II valgus knees: posterior stabilized or cruciate retaining?

PURPOSE: Type II valgus knees are defined by medial collateral ligament laxity. This paper studies the results of posterior stabilized (PS) and cruciate retaining (CR) knee implants in type II valgus knees. METHODS: From 1999 to 2009, there were 100 type II valgus knees in 95 patients eligible for study (63 PS, 37 CR). Patients had prospectively collected clinical data up to 2 years after surgery. RESULTS: At 24 months after surgery, the CR group had reduced range of motion (PS: median 126.0°, CR: median 114°; n.s.) and a marginally but statistically significant increased valgus alignment (PS: median 5°, CR: median 6°; p = 0.011). Despite this, both groups produced equal and marked improvements in SF-36, function score and knee score of the Knee Society score, and Oxford knee score. CONCLUSIONS: Overall, both PS and CR implants performed equally well in type II valgus knees at 24 months post-operatively. Further longer-term studies would be warranted to assess for late instability. LEVEL OF EVIDENCE: Retrospective, Level III.

Weber osteotomy for large Hill-Sachs Defects: clinical and CT assessments.

BACKGROUND: The Weber derotation osteotomy is an uncommon procedure that typically is reserved for patients with engaging Hill-Sachs defects who have had other surgical treatments for shoulder instability fail. It is unknown whether the desired humeral derotation actually is achieved with the Weber osteotomy. QUESTIONS/PURPOSES: The purposes of this study were to answer the following questions: (1) What are the complication (including redislocation) and reoperation rates of the Weber osteotomy? (2) What are the American Shoulder and Elbow Surgeons (ASES) and functional (ROM in internal rotation, self care) results? (3) What fraction of the patients had humeral derotation within 10° of the desired rotation? METHODS: A chart review of 19 Weber osteotomies and clinical assessment of 10 Weber osteotomies were performed by independent clinicians. The chart review, at a mean followup of 51 months (range, 13-148 months), focused on the complication rate and the frequency of redislocation. The clinical and CT assessments, at a mean followup of 54 months (range, 26-151 months), focused on ASES scores, ability of patients to perform self care with the affected arm, and CT scans to measure change in humeral retroversion. RESULTS: There were 25 complications and nine reoperations in 17 patients (19 shoulders), including pain (six patients, of whom one had complex regional pain syndrome), hematoma, infection, nonunion, delayed union, reoperations related to hardware and other noninstability-related causes (five patients), and internal rotation deficit. Redislocation occurred in one patient, who underwent repeat surgery, and subjective instability developed in two others. The mean ASES score was 78 points (of 100 points); six of the 10 patients (11 procedures) evaluated in person found it difficult or were unable to wash their backs with the affected arm. Humeral derotation varied from 7° to 77°; only three of the nine patients for whom CT scans were available had derotation within 10° of the desired rotation. CONCLUSIONS: Complication rates with the Weber osteotomy were much higher than previously reported. Because seven of 17 patients were lost to followup, the redislocation rate may be higher than we observed here. Given the unpredictable variability in humeral derotation achieved with a Weber osteotomy, an improved surgical technique is critical to avoid osteoarthritis and loss of internal rotation associated with overrotation.

Joint line changes and outcomes in constrained versus unconstrained total knee arthroplasty for the type II valgus knee.

PURPOSE: The objective of this study was to compare the outcome of constrained and unconstrained primary total knee arthroplasty (TKA) in the management of the valgus deformity. METHODS: This is a retrospective review of patients with type II valgus knee who underwent primary TKA from 1999 to 2011. There were fifty patients in Group 1 who underwent varus-valgus constrained TKA. They were matched with another fifty patients in Group 2 who underwent unconstrained TKA. RESULTS: The mean joint line shift was significantly higher in Group 1 (+8 mm, SD 6 mm) than in Group 2 (+2 mm, SD 3 mm) (p = 0.03). At 2 years, there was no difference in anterior-posterior stability and mediolateral stability according to the Knee Society Score, and patients in Group 2 reported significantly better mean function score of 66.2 (SD 9.3) (mean 48, SD 7.1 in Group 1) (p = 0.002). Two patients (6 %) in Group 1 underwent revision surgery--one for a broken central peg and the other for aseptic loosening. Three patients (2 %) in Group 2 underwent revision surgery--two for global instability and one for poly wear. The estimated survivorship time was 8.3 years for constrained TKA and 12.0 for unconstrained TKA. CONCLUSION: Constrained TKA was associated with more significant joint line changes for the management of valgus arthritic knee, when compared with unconstrained TKA. LEVEL OF EVIDENCE: Retrospective study, Level III.

A new navigation-based technique for lateral distalizing condylar osteotomy in patients undergoing total knee arthroplasty with fixed valgus deformity.

PURPOSE: In a prospective, consecutive study, a navigation-based technique for calculating the sliding distance of the lateral epicondyle prior to osteotomy in TKA surgery of fixed valgus deformity has been developed, and early results have been evaluated. MATERIALS AND METHODS: Twenty-seven knees with a fixed valgus deformity undergoing TKA received this new treatment. Clinical scores and radiograph evaluation were performed preoperatively and 1-year postoperatively. Static and dynamic kinematic data were obtained from navigation at the beginning and at the end of surgery. RESULTS: The calculated amount of sliding distance varied between 5 and 16 mm. No complications regarding this technique occurred. All clinical scores showed a significant improvement, and radiological evaluation showed a correction of all parameters in 100 % of patients. CONCLUSION: With this navigation-based technique, it is possible to calculate the amount of sliding distance prior to osteotomy and obtain excellent early results. All axes have been corrected completely, and flexion and extension gaps were balanced. No specific complications of this technique have occurred so far. LEVEL OF EVIDENCE: II.

Rotational limb alignment changes following total knee arthroplasty.

PURPOSE: The aim of the present study was to assess the changes in rotational alignment introduced by total knee arthroplasty (TKA) and the reproducibility of pre- and postoperative CT measurements of rotational limb alignment. METHODS: For this purpose we analyzed data from 196 consecutive cruciate-retaining, fixed bearing Columbus TKA procedures. Both pre- and postoperative scans torsion difference CT scans were available for measurements in 89 cases. Using these CT scans the neck-malleolar angle (NMA), the femoral posterior condylar angle (fPCA), the tibial posterior condylar axis (tPCA) and the tibial torsion angle (TTA) were independently assessed by three raters. CT scans were re-evaluated 8 weeks later by the most experienced rater for assessment of intraobserver agreement. RESULTS: Measurements of all angles were prone to high standard deviations reflecting interindividual variability. Mean fPCA changed from 1.3° to 2.7° internal rotation preoperatively to 0.1°-1.9° internal rotation postoperatively. Based on a relative external rotation of the tibial base plate as compared to the preoperative situation, we found a relative internal rotation of the postoperative NMA and tibial torsion of 3°-5.4° and 6°-7.5°, respectively. Intra- and interobserver agreement was strong for all angles assessed (ICCs 0.7-1.0) except for fPCA (ICC 0.2-0.6). However, mean absolute measurement differences for fPCA were clinically acceptable (1.2°-2.6°). CONCLUSIONS: Reproducibility of CT rotational limb alignment measurements was found to be clinically acceptable. Rotational alignment of the femoral and even more so of the tibial component will ultimately affect the rotational alignment of the entire limb-at least when fixed bearings are used. LEVEL OF EVIDENCE: Diagnostic study, Level III.

Coronal alignment is a predictor of the rotational geometry of the distal femur in the osteo-arthritic knee.

PURPOSE: There is a lot of inter-individual variation in the rotational anatomy of the distal femur. This study was set up to define the rotational anatomy of the distal femur in the osteo-arthritic knee and to investigate its relationship with the overall coronal alignment and gender. METHODS: CT-scans of 231 patients with end-stage knee osteo-arthritis prior to TKA surgery were obtained. This represents the biggest series published on rational geometry of the distal femur in literature so far. RESULTS: The posterior condylar line (PCL) was on average 1.6° (SD 1.9) internally rotated relative to the surgical transepicondylar axis (sTEA). The perpendicular to trochlear anteroposterior axis (⊥TRAx) was on average 4.8° (SD 3.3°) externally rotated relative to the sTEA. The relationship between the PCL and the sTEA was statistically different in the different coronal alignment groups (p < 0.001): 1.0° (SD 1.8°) in varus knees, 2.1° (SD 1.8°) in neutral knees and 2.6° (SD 1.8°) in valgus knees. The same was true for the ⊥TRAx in these 3 groups (p < 0.02).There was a clear linear relationship between the overall coronal alignment and the rotational geometry of the distal femur. For every 1° in coronal alignment increment from varus to valgus, there is a 0.1° increment in posterior condylar angle (PCL vs sTEA). CONCLUSION: The PCL was on average 1.6° internally rotated relative to the sTEA in the osteo-arthritic knee. The relationship between the PCL and the sTEA was statistically different in the different coronal alignment groups. LEVEL OF EVIDENCE: III.