Dedication to quality has a longstanding tradition within the Schulthess Clinic. Pioneering documentation Maurice E. Müller initiated an International Documentation & Evaluation System (IDES) in the era of hip replacement becoming an increasingly wide spread and standardized procedure. Starting in 1984, IDES was used to document each and every hip replacement and as of 1995 also for every knee arthroplasty performed. Norbert Gschwend became the driving authority in the clinic for standardizing documentation and regular long term follow-up intervals for all patients.

With increasing interest in patient reported outcomes (PROMs) a shift took place in the basic conception and electronic means (iPads) were introduced in 2012 to let patients complete their part of questionnaires, i.e. EQ-5D, OHS, OKS, UCLA & WOMAC while the clinical part was addressed in the same manner using HHS & KSS.

Optimizing user experience while answering routine questions and allowing for the physician to quickly enter required data without the numbing experience of ever same paper forms largely increased the return on information. This approach also guarantees for complete data sets, often a problem when using pen and paper.

Using these modern tools in combination with a refined recall procedure, we today show follow-up rates of well over 90% in the first post-operative years vs rates of 80% or less prior to introduction.

As of late 2012 the Swiss implant registry for knees & hips was introduced and here again we today use iPads with an app specifically designed to quickly document and register all operations on a daily base, reducing the chore of using paper or web based on line options from 3 to 10 minutes per operation to a mere 20 seconds, fully plausibilized and in this way never returned for corrections.

Pooling this data allows not only for generalized and stringent quality control but also facilitates spotting aberrant trends in the sense of an early warning system within our clinic with regard to procedures and implants.

Pioneering this approach to facilitate & perfect all documentation related procedures we aspire towards an elevated quality level in reporting to help sustain & guarantee patient satisfaction despite the high day-by-day volume.

INTRODUCTION

There is ongoing debate about the possible advantages of unicompartmental (UNI) knee replacement versus total knee replacement (TKR), such as for young, active patients. The purpose of this study was to investigate functional, radiographic, and device survivorship outcomes of UNI knee replacement with a newer generation UNI through 2-years post-op.

Introduction

Patellofemoral complications remain a very common post-operative problem in association with total knee arthoplasty (TKA). As malrotation of the femoral component is often considered crucial for the outcome, we analyzed absolute rotational femoral alignment in relation to patellar tracking pre- and postoperatively and matched the results with the two year functional outcome.

Concerns recently arose regarding hip resurfacing arthroplasty (HRA), mainly referring to the metal-on-metal articulation that results in increased metal ion concentrations and that may be associated with weird soft tissue reactions. Although a number of short-term reports highlighted excellent and encouraging outcomes after HRA, mid- to long-term follow-up studies are sparse in the current literature. This study aimed to determine the five-year results of HRA using the Durom^® prosthesis in the first consecutive 50 cases. We prospectively assessed clinical and radiographic data for all patients undergoing HRA with this implant. Follow-ups were scheduled at six weeks, one year, two years and five years after surgery. All complications, revisions and failures were noted. Harris Hip Scores (HHS) and the range of motion (ROM) were determined preoperatively and at each follow-up. Oxford Hip Scores (OHS) and University of California at Los Angeles (UCLA) activity levels were determined at the last control. Comparisons were performed using paired t-tests after testing for normal distribution. The cohort comprised 13 women and 36 men (50 hips) with a mean age of 53.3 ± 10.7 years and a mean BMI of 25.9 ± 3.7 kg/m2. After a mean follow-up of 60.5 ± 2.3 months five hips had to be revised, corresponding to a resvision rate of 10%. There occurred two femoral neck fractures (after two and eleven months) and one aseptic loosening of the femoral component (after 68 months). One implant was exchanged to a conventional stem-type design due to persistent hip pain (after eight months), and one hip underwent a femoral offset correction due to a symptomatic impingement between the neck and the cup (after 29 months). There occurred no intra- or other postoperative complications. Clinically, ROM significantly improved after surgery. Hip flexion increased from 91.1 ± 15.8° to 98.9 ± 6.5° (p=0.0007), internal rotation from 5.5 ± 6.9° to 11.1 ± 8.1° (p=0.0005), external rotation from 19.2 ± 12.5° to 28.8 ± 9.1° (p=0.0001), and abduction from 27.3 ± 10.5° to 40.2 ± 11.0° (p< 0.0001). The HHS significantly increased from 55.9 ± 12.3 points to 96.5 ± 8.5 points. The OHS averaged 14.3 ± 3.0 points, and UCLA activity levels averaged 7.7 ± 1.7. The present results demonstrate that despite satisfactory clinical outcomes in terms of patient scores and ROM, the high revision rate of 10% after a mid-term follow-up is disappointing.

Introduction: Cementless press-fit cups are the most widely used acetabular implants in total hip arthroplasty today. Their primary and secondary stability is largely determined by the design and choice of surface coating. Porous titanium coatings are used for the majority of cementless acetabular implants. However, an additional hydroxyapatite (HA) layer has been advocated for superior bone ongrowth. We studied the effect of additional HA coating on early micromotion of a porous titanium plasmasprayed cup with a flattened pole. A secondary objective was to compare the extent of micromotion of this well established cementless cup to data of other press-fit cups.

Methods: A total of 44 female patients (45 hips) undergoing total hip arthroplasty for osteoarthritis consented to participate in this prospective, IRB approved study. They were randomized for either a press-fit cup (EP-FIT PLUS^®, Plus Orthopedics AG, Switzerland) with a titanium plasma sprayed surface (Ti-group) or with additional HA coating (HA -group). All cups were used with the same combination of stem, PE liner and ceramic head. Model-based radiostereometry (MBRSA) was used to measure translation and rotation immediately postoperative, at 6 weeks, 3, 6, and 12 months. Statistical analysis of migration was performed utilizing one-sided Mann-Whitney tests and ANOVA.

Results: At one year, mean translation in the HA-group (Ti-group) along the medial-lateral (x), proximal-distal (y) and anterior-posterior (z) axes was −0.01 (0.07), 0.08 (0.09), and 0.03 (−0.06) mm, respectively. Mean rotation around the x-axis (anterior-posterior tilt) was −0.19 (−0.16), the y-axis (anteversion-retroversion) was −0.10 (−0.19), and the zaxis (adduction-abduction) was 0.23 (−0.05) degrees. Our hypothesis that translation and rotation would be different in the two groups was rejected (p< 0.00) for all dimensions except for rotation about the z-axis (p=0.10). The was no evidence for different migration patterns throughout the examined time points. All patients had excellent clinical outcome with a mean Harris Hip Score of 95.4 (HA-group) and 95.3 (Ti-group) (p=0.10). Plain radiographs of the cups showed good osseointegration.

Discussion: With excellent primary stability in both the Ti-group and the HA-group, we conclude, that HA-coating does not significantly increase stability of this flattened pole press-fit cup during the first postoperative year. We were able to show that the early stability of this cup is well comparable to that of the more frequently used hemispherical cups with initial stability being one prerequisite for long-term success. RSA measurements after 2 years will be conducted to confirm the current findings and the cup is also being studied in a long-term observation.

Introduction: Rotational alignment of the femoral component is widely believed to be crucial for the ultimate success of total knee arthroplasty (TKA). However there is a paucity of normative data on femoral component rotation in ‘perfect’ TKA.

Methods: Femoral component rotation in well-functioning TKA was assessed by means of axial radiography as described by Kanekasu et al. Well-functioning TKA were defined by three criteria at 5-year follow-up:

Knee Society objective and functional score of 190 or above

Thirty TKA of 29 patients (9 male, 20 female) with a median age of 70 years (range, 31–87) at time of surgery fulfilled the study criteria. All TKA were implanted at a single high-volume joint replacement center in 2002. In all cases both the condylar twist angle (CTA) using the clinical epicondylar axis (CEA) and the posterior condylar angle (PCA) using the surgical epicondylar axis (SEA) were used to assess rotational alignment of the femoral component.

Results: Overall, the mean CTA was 3.6+−3.5° of internal rotation (IR) (range, 4.1° of external rotation (ER) to 8.6° of IR) for the femoral component. For females, the CTA had a mean value of 4 +/−3.7° of IR (range, 7.6° of IR to 4.1° of ER) compared to 2.3 +/−3° of IR (range, 5.3° of IR to 2.5° of ER) in males. Overall, the mean PCA was 1.5 +/−3.5° of ER (range, 8.4° of ER to 5.1° of IR). In females, the mean PCA was 1 +/−3.9° ER (range, 2.3° of IR to 5.8° of ER) compared to 2.8 +/−2° ER (range, 0.4° of ER to 5.7° of ER) in males. The mean angle between CEA and SEA was overall 5.1 +/−1.8° (range, 3.3° to 9.1°), in females 5.1 +/−1.6° (range, 3.5° to 9.0°) compared to 5.0 +/−2.4° (range, 3.2° to 9.1°) in males.

Conclusion: Well-functioning TKA demonstrated a highly variable rotational alignment of the femoral component ranging from excessive external rotation to excessive internal rotation. These findings challenge current reference values for optimal femoral component rotation.

Introduction: Since the introduction of the Zimmer Innex UCOR (Ultra COgruent Rotating) mobile bearing total knee arthroplasty (TKA) system in 1999, there were close to 3000 primary TKAs performed at our institution utilizing this implant. We report on the first 396 5-year follow-up results and overall revisions in our total collective.

Methods: Between 1999 and 2006 there were 2734 primary Innex UCOR TKA performed (1748 female/987 male) at the Schulthess Clinic, Zurich. Primary diagnosis leading to TKA were OA (2462 – 90%), RA (144 – 5.3%), posttraumatic arthritis (65, 2.4%), necrosis (50, 1.8%) and misc causes (13 – 0.5%). The mean age of the females patients was 69y (33y – 92y), and 68y (31y – 93y) in the male population. To date 396 knees underwent clinical and radiological follow-up at 5 years (mean 5y 0m, range 4y 1m – 7y 2m), with 5% of the patients being lost to follow-up. Scoring was done, using the Knee Society Score (KSS). All patients had a full leg radiograph pre-operatively as well as at follow-up.

Results: Total KSS improved from 106.5 (6 – 184) pre-operatively to 179.5 (80 – 200) at follow-up, the knee score from 42.2 (2–93) to 92.1 (37 – 100), the function score from 64.3 (0–100) to 87.4 (10–100) respectively. The pain score increased from 17.7 (0–50) to 47.5 (20–50, 50 points maximum). ROM pre-operatively was 104.6° (0–145) and reached 117.2° at follow-up (55–145). Subjective evaluation by the patient at 5 years was excellent and good in 91%, fair in 8% and taxed poor by 1% of the patients. 95% of full leg radiographs showed a femorotibial angle of 182°–188°, 3% were < 182° (varus), 2% > 188° (valgus). Overall revision rate (95 of 2735) was 3.5%, 1.1% for infections and 1% for anterior knee pain and/or patella pathology. 0.6% were revised for instability, 0.3% for arthrofibrosis, and the remaining 0.5% for various problems.

Conclusion: These promising 5 year observations with the Innex UCOR mobile bearing TKA system suggest favorable overall midterm results. Further longer term follow-up evaluations are scheduled while 5 year follow-ups are ongoing, allowing for continuing reports on long-term performance.

Purpose

Overall outcome of bilateral hip and knee arthroplasty in the same patient with special regard to scheduling, postoperative complications and follow-up under consideration of the underlying disease.

Method

More than 6000 primary THA and 5500 primary TKA were implanted at Schulthess Clinic since 1985, 8% of which in rheumatoid patients. Quadruple THA and TKA was performed in a total of 51 rheumatoid patients. Mean follow-up for knees was 8. 5 years (1–17), and 9. 5 years (1–18) for hips. 67% of implants were uncemented. In 21% of patients, all four prostheses were implanted within one year and in over 50% within a five year period.

Results

Taking revision of components as failure there were three infections (CLS hip, GSB and LCS knee), two aseptic loosenings (Endler cup, GSB knee), two recurrent hip dislocations, three knee bearing exchanges (LCS, INNEX), and four patella component removals (GSB, PCA).

Conclusion

Quadruple arthroplasty in the lower extremity showed no increase of failure rate compared to single or dual arthroplasty patients. The results of this study support the indication for quadruple procedure with early postoperative rehabilitation and full weight bearing. Data suggest a procedure with hips before knees and at least two weeks between arthroplasty operations.