The “correct” rotational alignment and “normal” rotational alignment may not be the same position. Because of natural tibial plateau has average 3° varus but classical TKA method make tibial cut perpendicularly to tibial mechanical axis. Consequently femoral rotational compensation to 3° becomes necessary. While anatomical TKA method performed tibial cut in 3° varus. Then posterior femoral cut will be parallel to posterior condylar axis and component rotation theoretically should be aligned in natural anatomy. This study compares the rotational alignment between two methods. Study conducted on 80 navigated TKAs with modified gap technique. Intraoperative femoral rotation retrieved from navigation. Rotational alignment was calculated using the Berger protocol with postoperative computerised tomography scanning. The alignment parameters measured were tibial and femoral component rotations and the combined component rotations. 57 knees with PS design can be classified into 35 knees as anatomical group and 22 knees as classical group. 23 knees with CR design had 12 knees as anatomical group and 11 knees as classical group. The intraoperative femoral rotation in anatomical group had less external rotation than classical group significantly in PS design (0.77°±1.03° vs 2.86°±1.49°, p = 0.00) and also had the same results in CR design (1.33°±1.37°vs 2.64°±0.81°, p = 0.012). However, the postoperative excessive femoral and tibial component rotation compared with native value and combined rotation had no significant differences between classical and anatomical method in both implant design. Using CAS TKA with gap technique showed no difference in postoperative rotational alignment between classical and anatomical method.
One of four normal people had mechanical alignment of 3 degrees varus and more than so-called “constitutional varus”. Parallel joint line to the floor found in both neutral and varus alignment. Therefore, joint line orientation may play an important role in clinical outcomes after TKA. For reconstituting joint line parallel to the floor advocated by 30 varus tibial cut that was introduced by Hungerford The prospective study conducted on 94 primary varus osteoarthritis knees undergone CAS TKA using either classical method (51 knees) or anatomical method (43 knees). Clinical outcomes including WOMAC scores, Oxford knee scores and ROM were evaluated preoperatively and 6 months postoperatively. Full leg standing hip-knee-ankle were measured mechanical axis, tibial cut angle and tibial joint line angle at 6 months after surgery. The results revealed that postoperative neutral alignment (mechanical axis 0± 3°), 4–5°varus and ≥6°varus showed no significant difference in term of WOMAC scores, Oxford scores and ROM. Including comparison between classical tibial cut and anatomical tibial cut, postoperative joint line parallel to the floor and oblique joint line had no significant in clinical outcomes. Nevertheless, anatomical tibial cut and joint line parallel to the floor had significant WOMAC scores improvement than the others. In conclusion, the joint line parallel to the floor may be one of key successes after TKA more than postoperative limb alignment.
The problem associated with ceramic on ceramic total hip replacement (THR) is audible noise. Squeaking is the most frequently documented sound. The incidence of squeaking has been reported to wide range from 0.7 to 20.9%. Nevertheless there is no study to investigate on incidence of noise in computer assisted THR with ceramic on ceramic bearing. The purpose of this study was to determine the incidence and risks factors associated with noise. We retrospectively reviewed 200 patients (202 hips) whom performed computer assisted THR (Orthopilot, B. Braun, Tuttlingen, Germany) with ceramic on ceramic bearing between March 2009 and August 2012. All procedures underwent uncemented THR with posterior approach by single surgeon. All hips implanted with PLASMACUP and EXIA femoral stem (B. Braun, Tuttlingen, Germany). All cases used BIOLOX DELTA (Ceramtec, AG, Plochingen, Germany) ceramic liner and head. The incidence and type of noise were interviewed by telephone using set of questionnaire. Patient's age, weight, height, body mass index, acetabular cup size, femoral offset size determined from medical record for comparing between silent hips and noisy hips. The acetabular inclination angle, acetabular anteversion angle, femoral offset, hip offset were reviewed to compare difference between silent hips and noisy hips. The audible noise was reported for 13 hips (6.44%). 5 patients (5 hips) reported click (2.47%) and 8 patients (8 hips) squeaked (3.97%). The mean time to first occurrence of click was 13.4 months and squeak was 7.4 months after surgery. Most common frequency of click was less than weekly (60%) and squeak was 1–4 times per week (50%). Most common activity associated with noise was bending; 40% in click and 75% in squeaking. No patients complained for pain or social problem. Moreover, no patient underwent any intervention for the noise. The noise had not self-resolved in any of the patients at last follow up. Age, weight, height and BMI showed no statistically significant difference between silent hips and click hips. In addition, there was also same result between silent hips and squeaking hips. Acetabular cup insert size and femoral offset stem size the results showed that there was no statistically significant difference between silent hips and click hips, also with squeaking hips. Acetabular inclination, angle acetabular anteversion angle, femoral offset, hip offset the results shown that only acetabular anteversion angle differed significantly between silent hips (19.94±7.78 degree) and squeaking hips (13.46±5.54 degree). The results can conclude that incidence of noise after ceramic on ceramic THR with navigation was 6.44 %. Squeaking incidence was 3.97% and click incidence was 2.47%. The only associated squeaking risk factor was cup anteversion angle. In this study, squeaking hip had cup anteversion angle significant less than silent hip.
Gap planning in total knee arthroplasty (TKA) navigation is critically concerned. Osteophyte is one of the contributing factors for gap balancing in TKA. The osteophyte is normally removed before gap planning step. However, the posterior condylar osteophyte of femur is sometimes removed during the flexion gap preparation or may not be removed at all depends on individual case. This study attempts to investigate on how posterior condylar osteophyte affects on gap balancing and limb alignment during operation. The study was conducted on 35 varus osteoarthritis knees with posterior condylar osteophyte and undergone on TKA navigation. All knees were measured by CT scan for the size of posterior condylar osteophyte according to its width. Extension gap, flexion gap width, and limb alignment were measured by using the tension device with distraction force of 98 N on both medial and lateral sides under computer assisted surgery. The measuring of extension gap, flexion gap width, and limb alignment was undertaken before and after the posterior condylar osteophyte removal. This study reveals that the mean of the size of posterior condylar osteophyte after removal is 8.96 mm. The posterior condylar osteophyte has an effect on the increasing of medial extension gap and lateral extension in average 0.74 ± 0.72 mm. and 0.42 ± 0.67 mm. respectively. It also increases 0.71 ± 1.00 mm. in medial flexion gap and 0.97 ± 1.47 mm. in lateral flexion gap. After the posterior condylar osteophyte removal the mean of varus deformity is decreased 0.90° ± 1.14 ° while the mean of extension angle of sagittal limb alignment is increased 1.61°±1.69°. There is also a significant relationship between the size of posterior condylar osteophyte and the increasing of lateral flexion gap and also with the varus deformity decreasing. If the size of posterior condylar osteophyte is increased 10 mm. the lateral flexion gap will be increased 1.15 mm. and varus deformity will be decreased 0.75 degree.
