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Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_3 | Pages 18 - 18
23 Feb 2023
Grant M Zeng N Lin M Farrington W Walker M Bayan A Elliot R Van Rooyen R Sharp R Young S
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Joint registries suggest a downward trend in the use of uncemented Total Knee Replacements (TKR) since 2003, largely related to reports of early failures of uncemented tibial and patella components. Advancements in uncemented design such as trabecular metal may improve outcomes, but there is a scarcity of high-quality data from randomised trials.

319 patients <75 years of age were randomised to either cemented or uncemented TKR implanted using computer navigation. Patellae were resurfaced in all patients. Patient outcome scores, re-operations and radiographic analysis of radiolucent lines were compared.

Two year follow up was available for 287 patients (144 cemented vs 143 uncemented). There was no difference in operative time between groups, 73.7 v 71.1 mins (p= 0.08). There were no statistical differences in outcome scores at 2 years, Oxford knee score 42.5 vs 41.8 (p=0.35), International Knee Society 84.6 vs 84.0 (p=0.76), Forgotten Joint Score 66.7 vs 66.4 (p=0.91). There were two revisions, both for infection one in each group (0.33%). 13 cemented and 8 uncemented knees underwent re-operation, the majority of these being manipulation under anaesthetic (85.7%), with no difference (8.3% vs 5.3%, 95% CI -2.81% to 8.89%, p = 0.31). No difference was found in radiographic analysis at 2 years, 1 lucent line was seen in the cemented group and 3 in the uncemented group (0.67% v 2.09%, 95%CI -4.1% to 1.24%, p = 0.29).

We found no difference in clinical or radiographic outcomes between cemented and uncemented TKR including routine patella resurfacing at two years.

Early results suggest there is no difference between cemented and uncemented TKR at 2 years with reference to survivorship, patient outcomes and radiological parameters.


Orthopaedic Proceedings
Vol. 88-B, Issue SUPP_III | Pages 442 - 442
1 Oct 2006
Phillips A Bayan A
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Introduction: Several studies have shown that malalignment of primary knee replacement of more that three degrees result in rapid failure and less than optimal functional outcome. We investigated whether inaccuracies in registration resulted in malalignment and also what degree of registration error would result in an unacceptable result. The Stryker image free navigation system was used.

Method: Using a dry bone leg with restrained joints, we varied the points where registration was set and measured the resulting errors in alignment. Registration points used were 1: centre of the knee, 2: AP axis, 3: centre of the ankle and 4: medial malleolus. The true registration point was translated medially or laterally up to 10 mm or inclined up to ten degrees to simulate inaccurate placement.

Results: 1: less than 1° varus for 10mm of medial translation, 1.5° valgus for 10mm lateral translation on distal femoral cut. 2a: 0.5° valgus for 10mm medial translation and 0.5° valgus for 10° medial angulation on distal femoral cut. 2b: 0.5° varus for 10mm medial translation and no effect for 10° angulation on tibial cut. 3a: Software error with 10mm translation laterally and 1.5° varus for 10mm of lateral translation. 3b: 1.5° posterior slope and valgus angle for 30 degrees of lateral angulation. 4: 1° valgus for 10mm lateral translation and no effect on tibial slope.

Conclusion: There is not only no significant intra-observer error, but also that even combining registration errors may result in a cut error of only 1.5 degrees. The software itself also protected against any significant errors.


Orthopaedic Proceedings
Vol. 88-B, Issue SUPP_I | Pages 28 - 28
1 Mar 2006
Theis J Pennington J Bayan A Doyle T Hill R
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Purpose: There are numerous papers from specialist arthroplasty centres outlining results of total knee arthroplasties but little information from outside these major centres. We carried out a review of a fixed bearing total condylar knee replacement used in Dunedin by a variety of surgeons for over 10 years.

Method: All patients who received a Duracon/PCA fixed bearing total knee replacement between 1992 and 1996 were assessed clinically, fluoroscopically and completed an SF12, WOMAC and IKSS questionnaire.

Results: At a mean 9.7 (8–12) years follow up, 126 (69.6%) patients were available for review and 46 (25%) were deceased. The average age was 72 years (52–88) and the primary diagnosis was osteoarthritis in 95% of the cases. There were 34% Charnley Grade A, 37% Grade B and 29% Grade C respectively.

The average IKS Knee score was 72 (23–97) and the functional score was 68 (0–100) with 74% experiencing none or only mild pain. The SF12 assessment revealed a mean physical score of 55 (14–99). Ninety per cent of patients were satisfied with their knee and 89% would have the operation again if required.

There was one operative death (PE), one deep infection, 3 PE’s, 3 DVT’s and 5 superficial infections. An MUA was required in 9 cases.

Eight knees were revised. Using ‘all revisions’ as an end point. The survival rate was 95.3% at 10 years.

Conclusion: These results suggest that knee replacements carried out outside specialist arthroplasty centres perform very well with a survival rate of the implant of 95% at 10 years.


Orthopaedic Proceedings
Vol. 87-B, Issue SUPP_I | Pages 28 - 28
1 Mar 2005
Bayan A Orec R Pitto R
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In severe hip dysplasia the fixation of the cup becomes a technical hazard, and the augmentation of the acetabulum with an autologous bone graft is helpful when the bone stock is deficient.

Twenty-four patients (25 hips) were operated on between 1993 and 1994; the mean age at operation was 49 years (range, 28 to 71 years). The mean Sharp acetabular angle was 55degrees (range, 45 to 63degrees). The dislocation of the femoral head was graded Crowe 1 in 4 hips, grade II in 5 hips, Grade III in 10 hips, and grade IV in 6 hips. Autologus bone was harvested from the femoral head and from the proximal metaphysis of the femur. The fixation of the graft to the anterior wall and to the roof of the acetabulum was achieved using impaction using the reinforcement ring with hook of Ganz. A separate cohort of 25 patients (25 hips) operated on between 1998 and 1999 was investigated using radiostereometry (RSA).

The clinical outcome of the hips was prospectively reviewed using the Harris hip score at an average of 8.3 years (range 8 to 9 years) postoperatively. Twenty-four hips were pain-free, and had a range of motion of 210 degrees or more except 3. A positive Trendelenburg sign disappeared in 88% of the hips. One cup (4%) showed radiological loosening with migration and required revision surgery. No signs of migration or progressive radiolucent lines were present in the remaining hips. The graft appeared united without resorption in 24 hips. The results of micromotion analysis using RSA confirm the stable fixation of the reinforcement ring in dysplasia.

Satisfactory middle term results of total hip replacement for severe dysplasia can be achieved using appropriate surgery and specific components. The use of reinforcement ring is important to obtain adequate primary stability, and to protect the graft during healing.


Orthopaedic Proceedings
Vol. 85-B, Issue SUPP_III | Pages 203 - 203
1 Mar 2003
Pennington J Hill R Bayan A Doyle T Theis J
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There are numerous papers from specialist arthroplasty centres outlining results of total knee replacement. This review was performed as there is little information on results in general orthopaedic centres. All patients received a Duracon/PCA replacement between 1992 and 1996. Patients were assessed clinically, fluoroscopically and completed SF12, WOMAC and IKSS questionnaires. At a mean of 6.7 (5–9) years follow up 93 (78%) were available for review. The average age was 70 years (52–88) with 58% being male. The primary diagnosis was osteoarthritis in 94.3%, with 41 %, 38% and 21 % being Charnley grades A, B and C respectively.

The average IKS knee score was 71.4 (23–96) and functional score 70 (0–100), with 72.7% experiencing none or only mild pain. The SF12 assessment revealed a mean physical score of 38 (14–63) and mental score of 53 (25–67). There were 88.6% of patients satisfied with their knee and 92% would have the operation again if required. There were no deep infections or PE’s but there were 7 superficial infections and 2 DVT’s. A MUA was required in 8 patients. One patient retains a radiologically loose prosthesis at 8 years but had mild pain with stairs only, a WOMAC functional score of 85 and was happy. There was a best-case survival of 94.4% at 5 years. There were 5 knees revised in 5 patients and no revisions of the deceased patients, all surviving greater than 5 years from surgery. These results suggest that those in general orthopaedic centres are a little less reliable than those in specialist centres. However they are acceptable and patient satisfaction remains high.


Orthopaedic Proceedings
Vol. 84-B, Issue SUPP_III | Pages 286 - 286
1 Nov 2002
Bayan A Danesh-Clough T Theis J Veale G
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Aim: To demonstrate the pattern and mechanism of injury of alpine skiing and snowboarding, and to evaluate the potential risk factors.

Methods: We analysed prospectively all cases of orthopaedic injuries requiring hospital admission that were the result of snowboarding or skiing accidents in the winter of 2000. This included four popular skiing facilities in the South Island of New Zealand.

Results: Seventy-six patients were reviewed. Of those, 30 cases were the results of accidents from snowboarding and 44 cases were from skiing. In addition to appropriate medical evaluations and medical care, a detailed examination was performed on every patient to determine various factors, including demographics, their level of experience and the cause and mechanism of the accident. There were 47 males and 29 females, with an average age of 28 (range: seven to 62)years. Snowboarders tended to be younger men with an average age of 23 years compared with 31 years in skiers. Males constituted 77% of snowboarders and 54% of skiers.

There were 14 patients in the beginners’ group, 32 intermediate, 20 advanced and nine at an extreme-skill level. Thirty-eight patients sustained injuries of the lower extremities, 24 of the upper extremities, 13 of the spine, and one of the pelvis. Lower extremity injuries were more common in skiers (59% of lower limbs, versus 25% of upper limbs), while in snow boarding upper extremity injuries were more common (43% upper limbs versus 36% lower limbs). Ulnar collateral ligament injuries of the metacarpophalangeal joint of the thumb, were far more common in skiers (six in skiers versus one on snowboard). Sixteen patients (nine skiers and six snow-boarders) sustained diaphyseal fractures of their tibiae. In all nine patients in the skiing group, the mechanism of injury was failure of the binding to release resulting in a twisting force to the leg, while in the snowboarding group, three patients (50%) fractured their tibiae on landing badly from a jump and in the other three on colliding with another person or a fixed object.

Conclusions: Lower extremity, equipment-related injuries are common in alpine skiing. The data suggested that currently used bindings are insufficient. Research, technical developments and optimal adjustment of binding are required.


Orthopaedic Proceedings
Vol. 84-B, Issue SUPP_II | Pages 132 - 132
1 Jul 2002
Bayan A Matheson J
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Eighty-one patients treated surgically for non-insertional Achilles’ tendinopathy between 1987 and 1999 by one surgeon were reviewed by a comprehensive postal questionnaire. Fifty-six patients (73 tendons) returned a questionnaire at an average of 58.7 months after surgery. The duration of preoperative symptoms averaged 24.6 months. In all cases, conservative treatment was first attempted but failed to alleviate symptoms. Twenty (35.7%) of these patients were involved in competitive or serious recreational sport. There were 34 men and 22 women with a mean age of 42.5 years (range: 23 to 66). All patients who had insertional tendinopathy or retrocalcaneal bursitis were excluded from this study. The surgical procedure consisted of excision of the paratenon circumferentially and early mobilisation. All patients had the same post operative treatment. There were 77.5% excellent, 6.4% good, 6.4% fair and 6.4% poor results. Eleven percent developed complications post operatively. We concluded that surgical decompression of the Achilles’ tendon is a very effective treatment for patients with non-insertional Achilles’ tendinopathy who have failed conservative treatment.