The Authors performed a matched paired study between 2 groups UKR or CA-TKR implanted with a mini-incision (MICA group) in the treatment of isolated medial compartment knee arthritis. The Authors hypothesized that UKR offers a real less invasive surgery with lower economical costs despite a worse limb/implant alignment. Furthermore at a minimum 40 months follow-up they hypothesized that this small implant guarantees still both better clinical score and patient satisfaction than in the MICA group.

Thirty two patients with isolated medial compartment knee arthritis who underwent to a medial UKR from February 2001 to September 2002 were included in the study (UKR group). In all 32 knees the arthritic change was graded according to the classification of Älback ¹. Arthritic change did not exceed grade IV in the medial compartment and grade II in the patello-femoral compartment. All patients had an asymptomatic patello-femoral joint. All patients had a varus deformity lower than 8° and a body mass index lower than 30. No patient had any clinical evidence of ACL laxity or flexion deformity and all had a preoperative range of motion of a least 110°. At a minimum follow-up of 48 months, every single patients in group A was matched with a patient who had undergone a computer assisted TKR performed with a less invasive approach (shorter than 12 cm) for an isolated medial compartment knee arthritis between August 1999 and September 2002 (MICA group) in our hospital. At latest follow-up the clinical outcome was evaluated using both the Knee Society Score and a dedicated UKR score developed by the Italian Orthopaedic UKR Users Group (GIUM). The HKA angle and the Frontal Tibial Component angle (FTC) were measured at latest follow up on long leg standing anterior-posterior radiographs and the mean values between the 2 surgeons assessments were used as final values. Furthermore during the hospital staying we registered in both the groups when each patient was standing comfortably in full weight-bearing according to a self- answered questionnaire and the data were compared. Statistical analysis of the results was performed using parametric test (Student’s t-test). A statistical comparison of the percentage of results for the GIUM score was performed using the Chi-square test. A statistically significant result was given a p≤ 0.05.

Both hospital stay and operative time were statistically longer obviously in MICA group. In the UKR group the mean surgical time was 51.5 minutes (range: 36–75) (p< 0.001) while in the MICA group was 108.8 minutes (range: 80–132) (p< 0.001). In the UKR group the patients remained in the hospital for a mean of 5.1 days (range: 3–7) and in the MICA group 8.2 days (range: 4–16). At the latest follow-up the mean Knee Society Score was 80.5 (range: 70–100) and 78.4 (range: 70–87) for group A and B respectively. No statistically significant difference was seen for the Knee Society score between the 2 groups (p=0.08). The mean Functional score was 83.5 (range: 73–100) for group A and 78.8 (range: 59–90) for group B. A statistically significant difference was seen for the Functional score with superior results for group A (p=0.02). A statistically significant difference was seen for the GIUM score with better results for group A (p=0.01). The mean GIUM score was 76 (range: 67–90) and 73.02 (mean: 65–85) for group A and B respectively. At latest follow up the mean HKA angle was 176.8° for group A (range: 174°–182°) and 179.3° for group B (range 177–182) (p< 0.001). The mean FTC angle was 86.9° (range: 84°–90°) and 89.4° (range: 87°–92°) for group A and B respectively (p< 0.001). All TKR implants were positioned within 4 degrees of a HKA angle of 180° and FTC angle of 90°.

At the latest follow-up (minimum 48 months) no statistically significant difference was seen in the postoperative Knee Society score for either group. However, significant differences were seen between the 2 groups in the functional results and in the GIUM score with better results in the UKR group. All the patients achieved a range of motion greater than 120° and could walk for longer distances. During the hospital staying in this group the patients reported a statistically significant earlier full weight-bearing. This was despite a significant less accurate limb alignment. In addition to inferior results for the computer assisted mini-invasive TKR group the costs of the procedure were obviously greater because of the expensive implants and technology along with statistically significant longer surgical times and hospital stay

Nowadays unicompartimental knee replacement (UKR) is a valuable solution for the treatment of knee osteoarthritis. Likewise in selected cases bicompartimental arthritis of the knee in patient younger than sixty still remains a challenge for the orthopaedic surgeon. In this selected cases, the Authors present their experience in performing a mini-invasive bi-unicompartimental knee replacement assisted by a computer navigation system trying to obtain both a correct alignment and a soft tissue balancing.

From January to December 2003, the Authors treated 5 patients (5 knees) with bicompartimental arthritis of the knee. The mean age was 66 and in all the cases there was a arthritis deformity with intact both ACL and PCL without any pain at the femur-patella joint. All the patients had previously undergone to multiple surgical procedures. Orhophilot (4.0 version) navigation system (Aesculap, Tuttlingen, Germany) was used during the surgery to assist prosthesis placement. In all the cases a minimal surgical approach was used (7 to 9 cm skin cut). The patients were assessed using a UKR dedicated outcome score, Italian UKR User’s Group (G.I.U.M.) score, pre-operatively and at the latest follow-up. Pre-operatively the mean GIUM score was 49.1 (range 26–63) At the lastest follow-up the mean GIUM score was 80.2 (range :75–94). The average femoral-tibial angle was 179° (range 177° −181°). All the patients had a good ligament balancing with computer assisted spreader device. All the patients were satisfied and had returned to their previous occupation soon.

According to their previous experience performing bi-unicompartimental prosthesis, the Authors underline how the computer navigation system support ligaments balancing and a correct prostheses alignment. They emphasize this real mini-invasive surgical approach to the cure of the knee arthritis, above all in young patients with post traumatic deformities.

Introduction: Drainage of the surgical wound following major surgical procedures is advocated to avoid haematoma formation. Recently the need for of wound drainage in joint arthroplasty has been questioned. The aim of this prospective randomised study is to determine the benefits of a postoperative closed-suction drain after UKR.

Material and Methods: In a prospective randomised trial we evaluated the use of a postoperative closed-suction drain in unicompartmental knee replacement. Seventy-eight patients were divided into two groups: one without a postoperative closed-suction drain (Group A) and one with a drain (Group B). Both groups were matched for age, sex, and pre-operative haemoglobin.

Results: In group A we observed a lower day one postoperative analgesic requirement, smaller knee circumference 3 days postoperatively and less local wound complications. No deep infections occurred in either group during the follow-up period. Drain usage in UKR resulted in no significant advantage in postoperative pain, range of motion, and hospital stay. Post-operative drainage does however increase the cost of the procedure both in labour and equipment expenditure.

Conclusions: We conclude that avoiding postoperative closed-suction drainage in UKR does not influence the final outcome.

Introduction: Nowadays bicompartimental arthritis of the knee in patients younger than sixty still remains a challenge for the orthopaedic surgeon. In these selected cases, the authors present their experience in performing a mini-invasive bi-unicompartimental knee replacement assisted by computer navigation.

Materials and Methods: From January to December 2003, the authors treated 7 patients (7 knees) with bicompartimental arthritis of the knee. The mean age was 66 and in all the cases there was a arthritis deformity with no ligament deficiency and a pain-free femoro-patellar joint. The Orhopilot (4.0 version) navigation system was used during the surgery to assist prosthesis placement. In all the cases a minimal surgical approach was used (7 to 9 cm skin cut). The patients were assessed using a UKR dedicated outcome score (G.I.U.M. Score), pre-operatively and at the latest follow-up. Pre-operatively the mean GIUM score was 49.1 (range 26–63)

Results: At the lastest follow-up the mean GIUM score was 80.2 (range:75–94). The average femorotibial angle was 179° (range 177° −181°). A good ligament balance was achieved In all cases using a computer assisted spreader device. All the patients were satisfied and had returned to their previous occupation soon.

Conclusions: The authors underline how the computer navigation system supports ligament balancing and a correct prosthesis alignment. They registred no fracture of the tibial intercondylar eminence cause of wrong balancing and cuts. They emphasize this real mini-invasive surgical approach to the cure of the knee arthritis, above all in young patients with post traumatic deformities.

Malalignment in total knee replacement (TKR) is frequently associated with early failure and poor functional results. It has been suggested that errors in tibial and femoral alignment of > 3° occurs in at least 10% of TKR. Since 1999 we have been using a computer-based alignment system (Orthopilot;Aesculap,Tuttlingen,Germany) for TKR in more than 300 implants. The aim of this retrospective study is to present our experience in comparison with traditional alignment systems for TKR.

Patients receiving TKR with different alignment systems were enrolled in the study and assigned to three different groups. In group A (38 cases) TKR was performed using a computer-assisted alignment system, in group B (40 cases) TKR was performed using a totally intramedullary alignment system and in group C (37 cases) TKR was performed using a totally extramedullary alignment system. The criteria for inclusion were a diagnosis of primary osteoarthritis, a pre-operative mechanical frontal axis (MFA) ranging from 165° to 195°, and a pre-operative knee flexion deformity not exceeding 10° calculated according to pre-operative radiographs. The radiographs were assessed for the alignment of the femoral and tibial component and the lower limb alignment, considering the lateral femoral component angle (FCA), the medial tibial component angle (TCA), respectively.

The surgical time was statistically longer in the computer-assisted group. The results did not show statistically significant differences in FCA, TCA and MFA among the three groups. However, in the extramedullary aligned group there was a statistically higher percentage of TKRs with both an abnormal FCA and MFA compared to the computer-based alignment group. Furthermore, in the computer-based alignment group all the implants were aligned within 4° of an ideal MFA.

Our results demonstrate the significant improvement in the accuracy of implant alignment using a computer-assisted system compared to an extramedullary one. Furthermore, we underline how stressing the knee during all the phases of the registration process for the navigated implant can demonstrate how much of the deformity can be corrected and thus guide the soft-tissue release.

Unicompartmental knee arthroplasty (UKA) surgery has had a troubled history. In the late 1970s high failure rates and the success of bicondylar knee replacement made UKA less popular. Failures were mainly caused by improper implant design, incorrect patient selection and inadequate instrumentation. In the last few years the advent of guiding systems for more accurate alignment, new implant design and better patient selection have improved results and renewed interest in UKA.

We present a retrospective study of two consecutive series of 60 cases of UC-PLUS SOLUTION UKA and 60 cases of SEARCH AESCULAP computer-assisted total knee arthroplasty (TKA) using ORTHOPILOT software navigation, performed between September 1999 and September 2001. The patients, 45 men and 75 women, had a mean age of 69.5 years (47–85) and the two groups were comparable in terms of age, sex, size, weight (60–85 kg), aetiology, pre-operative range of motion (mean flexion: 100°; range: 90°–140°), pre-operative IKS score, mechanical axis and Alhlback radiographic degrees. The mean femoral-tibial angle was 175° (range:167°–195°). All the operations were performed by the same surgeon. Aim of the surgical procedure was to obtain an ideal femoral-tibial angle of 180°, relieve the pain and restore a better range of motion.

The results showed an excellent alignment of the limbs with the computer-assisted system, but a better IKS score in the UKA group as regards range of motion, pain and walking.

Nowdays bicompartmental arthritis of the knee in patients younger than 60 still remains a challenge for the orthopaedic surgeon. In these selected cases, the authors present their experience in performing a minimally invasive bi-unicompartmental knee replacement assisted by computer navigation.

From January to December 2003, the authors treated seven patients (seven knees) with bicompartmental arthritis of the knee. The mean age was 66 and in all the cases an arthritis deformity was present but with no ligament deficiency and a pain-free femur-patella joint. The Orhophilot (4.0 version) navigation system was used during the surgery to assist prosthesis placement. In all the cases a minimally invasive surgical approach was used (7- to 9-cm skin incision). The patients were assessed using a UKR dedicated outcome score (GIUM Score), pre-operatively and at the latest follow-up. Pre-operatively the mean GIUM score was 49.1 (range 26–63)

At the lastest follow-up the mean GIUM score was 80.2 (range :75–94). The average femoral-tibial angle was 179° (range 177°–181°). In all the cases a good ligament balancing was achieved using a computer-assisted spreader device. All the patients were satisfied and had returned to their previous occupation soon.

The authors underline how the computer navigation system supports ligament balancing and correct prosthesis alignment. They did not register any fracture of the tibial intercondylar eminence because of wrong balancing and incisions. They emphasise this truly minimally invasive surgical approach to the cure of knee arthritis, above all in young patients with post-traumatic deformities.

Tibial opening wedge osteotomy is still a worthwhile surgical procedure in the treatment of tibial varus deformity to prevent knee arthritis. However, it requires a long period without weight-bearing because of the need of bone harvesting substitution at the osteotomy site. The authors present their experience with endoscopic injection of Norian SRS calcium phosphate cement to speed patient recovery and to avoid any potential in soft tissue complications.

From January 2001 the authors performed 13 tibial opening wedge osteotomy in 12 patients. All the patients previously underwent to a knee arthroscopy. The average age was 51 years (range 35–56). In all cases the injection of Norian SRS calcium phosphate cement was controlled arthroscopically and the fixation was maintained with a Puddu’s plate. The patients were assessed using the GIUM Score, pre-operatively and at the latest follow-up.

The authors did not register any problems due to the Norian SRS calcium phosphate cement. Total weight-bearing was allowed after an average of 26 days. Radiographically the bone substitute appeared well integrated at the latest follow-up. Pre-operatively the mean GIUM score was 56.1 (range 36–68). At the latest follow-up the mean GIUM score was 94.2 (range 84–98). All the patients were satisfied and had returned to their previous occupation.

The authors suggest Norian SRS calcium phosphate cement to speed patientrecovery after tibial opening wedge osteotomy